~hc/RK356X_SDK_RELEASE.git

..	..	@@ -20,20 +20,33 @@
20	20	* OF THIS SOFTWARE.
21	21	*/
22	22
23		-#include <linux/kernel.h>
	23	+#include <linux/bitfield.h>
24	24	#include <linux/delay.h>
25		-#include <linux/init.h>
26	25	#include <linux/errno.h>
	26	+#include <linux/i2c.h>
	27	+#include <linux/init.h>
	28	+#include <linux/kernel.h>
	29	+#include <linux/random.h>
27	30	#include <linux/sched.h>
28	31	#include <linux/seq_file.h>
29		-#include <linux/i2c.h>
30		-#include <drm/drm_dp_mst_helper.h>
31		-#include <drm/drmP.h>
32	32	#include <linux/iopoll.h>
33	33
34		-#include <drm/drm_fixed.h>
	34	+#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	35	+#include <linux/stacktrace.h>
	36	+#include <linux/sort.h>
	37	+#include <linux/timekeeping.h>
	38	+#include <linux/math64.h>
	39	+#endif
	40	+
35	41	#include <drm/drm_atomic.h>
36	42	#include <drm/drm_atomic_helper.h>
	43	+#include <drm/drm_dp_mst_helper.h>
	44	+#include <drm/drm_drv.h>
	45	+#include <drm/drm_print.h>
	46	+#include <drm/drm_probe_helper.h>
	47	+
	48	+#include "drm_crtc_helper_internal.h"
	49	+#include "drm_dp_mst_topology_internal.h"
37	50
38	51	/**
39	52	* DOC: dp mst helper
..	..	@@ -42,27 +55,144 @@
42	55	* protocol. The helpers contain a topology manager and bandwidth manager.
43	56	* The helpers encapsulate the sending and received of sideband msgs.
44	57	*/
	58	+struct drm_dp_pending_up_req {
	59	+ struct drm_dp_sideband_msg_hdr hdr;
	60	+ struct drm_dp_sideband_msg_req_body msg;
	61	+ struct list_head next;
	62	+};
	63	+
45	64	static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
46	65	char *buf);
47		-static int test_calc_pbn_mode(void);
48	66
49		-static void drm_dp_put_port(struct drm_dp_mst_port *port);
	67	+static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
50	68
51	69	static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
52	70	int id,
53	71	struct drm_dp_payload *payload);
54	72
55		-static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
56		- struct drm_dp_mst_branch *mstb);
	73	+static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
	74	+ struct drm_dp_mst_port *port,
	75	+ int offset, int size, u8 *bytes);
	76	+static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
	77	+ struct drm_dp_mst_port *port,
	78	+ int offset, int size, u8 *bytes);
	79	+
	80	+static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
	81	+ struct drm_dp_mst_branch *mstb);
	82	+
	83	+static void
	84	+drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
	85	+ struct drm_dp_mst_branch *mstb);
	86	+
57	87	static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
58	88	struct drm_dp_mst_branch *mstb,
59	89	struct drm_dp_mst_port *port);
60	90	static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
61	91	u8 *guid);
62	92
63		-static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
64		-static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
	93	+static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
	94	+static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
65	95	static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
	96	+
	97	+static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
	98	+ struct drm_dp_mst_branch *branch);
	99	+
	100	+#define DBG_PREFIX "[dp_mst]"
	101	+
	102	+#define DP_STR(x) [DP_ ## x] = #x
	103	+
	104	+static const char *drm_dp_mst_req_type_str(u8 req_type)
	105	+{
	106	+ static const char * const req_type_str[] = {
	107	+ DP_STR(GET_MSG_TRANSACTION_VERSION),
	108	+ DP_STR(LINK_ADDRESS),
	109	+ DP_STR(CONNECTION_STATUS_NOTIFY),
	110	+ DP_STR(ENUM_PATH_RESOURCES),
	111	+ DP_STR(ALLOCATE_PAYLOAD),
	112	+ DP_STR(QUERY_PAYLOAD),
	113	+ DP_STR(RESOURCE_STATUS_NOTIFY),
	114	+ DP_STR(CLEAR_PAYLOAD_ID_TABLE),
	115	+ DP_STR(REMOTE_DPCD_READ),
	116	+ DP_STR(REMOTE_DPCD_WRITE),
	117	+ DP_STR(REMOTE_I2C_READ),
	118	+ DP_STR(REMOTE_I2C_WRITE),
	119	+ DP_STR(POWER_UP_PHY),
	120	+ DP_STR(POWER_DOWN_PHY),
	121	+ DP_STR(SINK_EVENT_NOTIFY),
	122	+ DP_STR(QUERY_STREAM_ENC_STATUS),
	123	+ };
	124	+
	125	+ if (req_type >= ARRAY_SIZE(req_type_str) \|\|
	126	+ !req_type_str[req_type])
	127	+ return "unknown";
	128	+
	129	+ return req_type_str[req_type];
	130	+}
	131	+
	132	+#undef DP_STR
	133	+#define DP_STR(x) [DP_NAK_ ## x] = #x
	134	+
	135	+static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
	136	+{
	137	+ static const char * const nak_reason_str[] = {
	138	+ DP_STR(WRITE_FAILURE),
	139	+ DP_STR(INVALID_READ),
	140	+ DP_STR(CRC_FAILURE),
	141	+ DP_STR(BAD_PARAM),
	142	+ DP_STR(DEFER),
	143	+ DP_STR(LINK_FAILURE),
	144	+ DP_STR(NO_RESOURCES),
	145	+ DP_STR(DPCD_FAIL),
	146	+ DP_STR(I2C_NAK),
	147	+ DP_STR(ALLOCATE_FAIL),
	148	+ };
	149	+
	150	+ if (nak_reason >= ARRAY_SIZE(nak_reason_str) \|\|
	151	+ !nak_reason_str[nak_reason])
	152	+ return "unknown";
	153	+
	154	+ return nak_reason_str[nak_reason];
	155	+}
	156	+
	157	+#undef DP_STR
	158	+#define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
	159	+
	160	+static const char *drm_dp_mst_sideband_tx_state_str(int state)
	161	+{
	162	+ static const char * const sideband_reason_str[] = {
	163	+ DP_STR(QUEUED),
	164	+ DP_STR(START_SEND),
	165	+ DP_STR(SENT),
	166	+ DP_STR(RX),
	167	+ DP_STR(TIMEOUT),
	168	+ };
	169	+
	170	+ if (state >= ARRAY_SIZE(sideband_reason_str) \|\|
	171	+ !sideband_reason_str[state])
	172	+ return "unknown";
	173	+
	174	+ return sideband_reason_str[state];
	175	+}
	176	+
	177	+static int
	178	+drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
	179	+{
	180	+ int i;
	181	+ u8 unpacked_rad[16];
	182	+
	183	+ for (i = 0; i < lct; i++) {
	184	+ if (i % 2)
	185	+ unpacked_rad[i] = rad[i / 2] >> 4;
	186	+ else
	187	+ unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
	188	+ }
	189	+
	190	+ /* TODO: Eventually add something to printk so we can format the rad
	191	+ * like this: 1.2.3
	192	+ */
	193	+ return snprintf(out, len, "%*phC", lct, unpacked_rad);
	194	+}
	195	+
66	196	/* sideband msg handling */
67	197	static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
68	198	{
..	..	@@ -134,6 +264,7 @@
134	264	static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
135	265	{
136	266	u8 size = 3;
	267	+
137	268	size += (hdr->lct / 2);
138	269	return size;
139	270	}
..	..	@@ -144,6 +275,7 @@
144	275	int idx = 0;
145	276	int i;
146	277	u8 crc4;
	278	+
147	279	buf[idx++] = ((hdr->lct & 0xf) << 4) \| (hdr->lcr & 0xf);
148	280	for (i = 0; i < (hdr->lct / 2); i++)
149	281	buf[idx++] = hdr->rad[i];
..	..	@@ -164,6 +296,7 @@
164	296	u8 len;
165	297	int i;
166	298	u8 idx;
	299	+
167	300	if (buf[0] == 0)
168	301	return false;
169	302	len = 3;
..	..	@@ -194,16 +327,20 @@
194	327	return true;
195	328	}
196	329
197		-static void drm_dp_encode_sideband_req(struct drm_dp_sideband_msg_req_body *req,
198		- struct drm_dp_sideband_msg_tx *raw)
	330	+void
	331	+drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
	332	+ struct drm_dp_sideband_msg_tx *raw)
199	333	{
200	334	int idx = 0;
201	335	int i;
202	336	u8 *buf = raw->msg;
	337	+
203	338	buf[idx++] = req->req_type & 0x7f;
204	339
205	340	switch (req->req_type) {
206	341	case DP_ENUM_PATH_RESOURCES:
	342	+ case DP_POWER_DOWN_PHY:
	343	+ case DP_POWER_UP_PHY:
207	344	buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
208	345	idx++;
209	346	break;
..	..	@@ -291,19 +428,301 @@
291	428	memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
292	429	idx += req->u.i2c_write.num_bytes;
293	430	break;
	431	+ case DP_QUERY_STREAM_ENC_STATUS: {
	432	+ const struct drm_dp_query_stream_enc_status *msg;
294	433
295		- case DP_POWER_DOWN_PHY:
296		- case DP_POWER_UP_PHY:
297		- buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
	434	+ msg = &req->u.enc_status;
	435	+ buf[idx] = msg->stream_id;
298	436	idx++;
	437	+ memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
	438	+ idx += sizeof(msg->client_id);
	439	+ buf[idx] = 0;
	440	+ buf[idx] \|= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
	441	+ buf[idx] \|= msg->valid_stream_event ? BIT(2) : 0;
	442	+ buf[idx] \|= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
	443	+ buf[idx] \|= msg->valid_stream_behavior ? BIT(5) : 0;
	444	+ idx++;
	445	+ }
299	446	break;
300	447	}
301	448	raw->cur_len = idx;
	449	+}
	450	+EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
	451	+
	452	+/* Decode a sideband request we've encoded, mainly used for debugging */
	453	+int
	454	+drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
	455	+ struct drm_dp_sideband_msg_req_body *req)
	456	+{
	457	+ const u8 *buf = raw->msg;
	458	+ int i, idx = 0;
	459	+
	460	+ req->req_type = buf[idx++] & 0x7f;
	461	+ switch (req->req_type) {
	462	+ case DP_ENUM_PATH_RESOURCES:
	463	+ case DP_POWER_DOWN_PHY:
	464	+ case DP_POWER_UP_PHY:
	465	+ req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
	466	+ break;
	467	+ case DP_ALLOCATE_PAYLOAD:
	468	+ {
	469	+ struct drm_dp_allocate_payload *a =
	470	+ &req->u.allocate_payload;
	471	+
	472	+ a->number_sdp_streams = buf[idx] & 0xf;
	473	+ a->port_number = (buf[idx] >> 4) & 0xf;
	474	+
	475	+ WARN_ON(buf[++idx] & 0x80);
	476	+ a->vcpi = buf[idx] & 0x7f;
	477	+
	478	+ a->pbn = buf[++idx] << 8;
	479	+ a->pbn \|= buf[++idx];
	480	+
	481	+ idx++;
	482	+ for (i = 0; i < a->number_sdp_streams; i++) {
	483	+ a->sdp_stream_sink[i] =
	484	+ (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
	485	+ }
	486	+ }
	487	+ break;
	488	+ case DP_QUERY_PAYLOAD:
	489	+ req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
	490	+ WARN_ON(buf[++idx] & 0x80);
	491	+ req->u.query_payload.vcpi = buf[idx] & 0x7f;
	492	+ break;
	493	+ case DP_REMOTE_DPCD_READ:
	494	+ {
	495	+ struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
	496	+
	497	+ r->port_number = (buf[idx] >> 4) & 0xf;
	498	+
	499	+ r->dpcd_address = (buf[idx] << 16) & 0xf0000;
	500	+ r->dpcd_address \|= (buf[++idx] << 8) & 0xff00;
	501	+ r->dpcd_address \|= buf[++idx] & 0xff;
	502	+
	503	+ r->num_bytes = buf[++idx];
	504	+ }
	505	+ break;
	506	+ case DP_REMOTE_DPCD_WRITE:
	507	+ {
	508	+ struct drm_dp_remote_dpcd_write *w =
	509	+ &req->u.dpcd_write;
	510	+
	511	+ w->port_number = (buf[idx] >> 4) & 0xf;
	512	+
	513	+ w->dpcd_address = (buf[idx] << 16) & 0xf0000;
	514	+ w->dpcd_address \|= (buf[++idx] << 8) & 0xff00;
	515	+ w->dpcd_address \|= buf[++idx] & 0xff;
	516	+
	517	+ w->num_bytes = buf[++idx];
	518	+
	519	+ w->bytes = kmemdup(&buf[++idx], w->num_bytes,
	520	+ GFP_KERNEL);
	521	+ if (!w->bytes)
	522	+ return -ENOMEM;
	523	+ }
	524	+ break;
	525	+ case DP_REMOTE_I2C_READ:
	526	+ {
	527	+ struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
	528	+ struct drm_dp_remote_i2c_read_tx *tx;
	529	+ bool failed = false;
	530	+
	531	+ r->num_transactions = buf[idx] & 0x3;
	532	+ r->port_number = (buf[idx] >> 4) & 0xf;
	533	+ for (i = 0; i < r->num_transactions; i++) {
	534	+ tx = &r->transactions[i];
	535	+
	536	+ tx->i2c_dev_id = buf[++idx] & 0x7f;
	537	+ tx->num_bytes = buf[++idx];
	538	+ tx->bytes = kmemdup(&buf[++idx],
	539	+ tx->num_bytes,
	540	+ GFP_KERNEL);
	541	+ if (!tx->bytes) {
	542	+ failed = true;
	543	+ break;
	544	+ }
	545	+ idx += tx->num_bytes;
	546	+ tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
	547	+ tx->i2c_transaction_delay = buf[idx] & 0xf;
	548	+ }
	549	+
	550	+ if (failed) {
	551	+ for (i = 0; i < r->num_transactions; i++) {
	552	+ tx = &r->transactions[i];
	553	+ kfree(tx->bytes);
	554	+ }
	555	+ return -ENOMEM;
	556	+ }
	557	+
	558	+ r->read_i2c_device_id = buf[++idx] & 0x7f;
	559	+ r->num_bytes_read = buf[++idx];
	560	+ }
	561	+ break;
	562	+ case DP_REMOTE_I2C_WRITE:
	563	+ {
	564	+ struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
	565	+
	566	+ w->port_number = (buf[idx] >> 4) & 0xf;
	567	+ w->write_i2c_device_id = buf[++idx] & 0x7f;
	568	+ w->num_bytes = buf[++idx];
	569	+ w->bytes = kmemdup(&buf[++idx], w->num_bytes,
	570	+ GFP_KERNEL);
	571	+ if (!w->bytes)
	572	+ return -ENOMEM;
	573	+ }
	574	+ break;
	575	+ case DP_QUERY_STREAM_ENC_STATUS:
	576	+ req->u.enc_status.stream_id = buf[idx++];
	577	+ for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
	578	+ req->u.enc_status.client_id[i] = buf[idx++];
	579	+
	580	+ req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
	581	+ buf[idx]);
	582	+ req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
	583	+ buf[idx]);
	584	+ req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
	585	+ buf[idx]);
	586	+ req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
	587	+ buf[idx]);
	588	+ break;
	589	+ }
	590	+
	591	+ return 0;
	592	+}
	593	+EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
	594	+
	595	+void
	596	+drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
	597	+ int indent, struct drm_printer *printer)
	598	+{
	599	+ int i;
	600	+
	601	+#define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
	602	+ if (req->req_type == DP_LINK_ADDRESS) {
	603	+ /* No contents to print */
	604	+ P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
	605	+ return;
	606	+ }
	607	+
	608	+ P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
	609	+ indent++;
	610	+
	611	+ switch (req->req_type) {
	612	+ case DP_ENUM_PATH_RESOURCES:
	613	+ case DP_POWER_DOWN_PHY:
	614	+ case DP_POWER_UP_PHY:
	615	+ P("port=%d\n", req->u.port_num.port_number);
	616	+ break;
	617	+ case DP_ALLOCATE_PAYLOAD:
	618	+ P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
	619	+ req->u.allocate_payload.port_number,
	620	+ req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
	621	+ req->u.allocate_payload.number_sdp_streams,
	622	+ req->u.allocate_payload.number_sdp_streams,
	623	+ req->u.allocate_payload.sdp_stream_sink);
	624	+ break;
	625	+ case DP_QUERY_PAYLOAD:
	626	+ P("port=%d vcpi=%d\n",
	627	+ req->u.query_payload.port_number,
	628	+ req->u.query_payload.vcpi);
	629	+ break;
	630	+ case DP_REMOTE_DPCD_READ:
	631	+ P("port=%d dpcd_addr=%05x len=%d\n",
	632	+ req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
	633	+ req->u.dpcd_read.num_bytes);
	634	+ break;
	635	+ case DP_REMOTE_DPCD_WRITE:
	636	+ P("port=%d addr=%05x len=%d: %*ph\n",
	637	+ req->u.dpcd_write.port_number,
	638	+ req->u.dpcd_write.dpcd_address,
	639	+ req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
	640	+ req->u.dpcd_write.bytes);
	641	+ break;
	642	+ case DP_REMOTE_I2C_READ:
	643	+ P("port=%d num_tx=%d id=%d size=%d:\n",
	644	+ req->u.i2c_read.port_number,
	645	+ req->u.i2c_read.num_transactions,
	646	+ req->u.i2c_read.read_i2c_device_id,
	647	+ req->u.i2c_read.num_bytes_read);
	648	+
	649	+ indent++;
	650	+ for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
	651	+ const struct drm_dp_remote_i2c_read_tx *rtx =
	652	+ &req->u.i2c_read.transactions[i];
	653	+
	654	+ P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
	655	+ i, rtx->i2c_dev_id, rtx->num_bytes,
	656	+ rtx->no_stop_bit, rtx->i2c_transaction_delay,
	657	+ rtx->num_bytes, rtx->bytes);
	658	+ }
	659	+ break;
	660	+ case DP_REMOTE_I2C_WRITE:
	661	+ P("port=%d id=%d size=%d: %*ph\n",
	662	+ req->u.i2c_write.port_number,
	663	+ req->u.i2c_write.write_i2c_device_id,
	664	+ req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
	665	+ req->u.i2c_write.bytes);
	666	+ break;
	667	+ case DP_QUERY_STREAM_ENC_STATUS:
	668	+ P("stream_id=%u client_id=%*ph stream_event=%x "
	669	+ "valid_event=%d stream_behavior=%x valid_behavior=%d",
	670	+ req->u.enc_status.stream_id,
	671	+ (int)ARRAY_SIZE(req->u.enc_status.client_id),
	672	+ req->u.enc_status.client_id, req->u.enc_status.stream_event,
	673	+ req->u.enc_status.valid_stream_event,
	674	+ req->u.enc_status.stream_behavior,
	675	+ req->u.enc_status.valid_stream_behavior);
	676	+ break;
	677	+ default:
	678	+ P("???\n");
	679	+ break;
	680	+ }
	681	+#undef P
	682	+}
	683	+EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
	684	+
	685	+static inline void
	686	+drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
	687	+ const struct drm_dp_sideband_msg_tx *txmsg)
	688	+{
	689	+ struct drm_dp_sideband_msg_req_body req;
	690	+ char buf[64];
	691	+ int ret;
	692	+ int i;
	693	+
	694	+ drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
	695	+ sizeof(buf));
	696	+ drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
	697	+ txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
	698	+ drm_dp_mst_sideband_tx_state_str(txmsg->state),
	699	+ txmsg->path_msg, buf);
	700	+
	701	+ ret = drm_dp_decode_sideband_req(txmsg, &req);
	702	+ if (ret) {
	703	+ drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
	704	+ return;
	705	+ }
	706	+ drm_dp_dump_sideband_msg_req_body(&req, 1, p);
	707	+
	708	+ switch (req.req_type) {
	709	+ case DP_REMOTE_DPCD_WRITE:
	710	+ kfree(req.u.dpcd_write.bytes);
	711	+ break;
	712	+ case DP_REMOTE_I2C_READ:
	713	+ for (i = 0; i < req.u.i2c_read.num_transactions; i++)
	714	+ kfree(req.u.i2c_read.transactions[i].bytes);
	715	+ break;
	716	+ case DP_REMOTE_I2C_WRITE:
	717	+ kfree(req.u.i2c_write.bytes);
	718	+ break;
	719	+ }
302	720	}
303	721
304	722	static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
305	723	{
306	724	u8 crc4;
	725	+
307	726	crc4 = drm_dp_msg_data_crc4(msg, len);
308	727	msg[len] = crc4;
309	728	}
..	..	@@ -319,55 +738,53 @@
319	738	raw->cur_len = idx;
320	739	}
321	740
322		-/* this adds a chunk of msg to the builder to get the final msg */
323		-static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
324		- u8 *replybuf, u8 replybuflen, bool hdr)
	741	+static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
	742	+ struct drm_dp_sideband_msg_hdr *hdr,
	743	+ u8 hdrlen)
325	744	{
326		- int ret;
	745	+ /*
	746	+ * ignore out-of-order messages or messages that are part of a
	747	+ * failed transaction
	748	+ */
	749	+ if (!hdr->somt && !msg->have_somt)
	750	+ return false;
	751	+
	752	+ /* get length contained in this portion */
	753	+ msg->curchunk_idx = 0;
	754	+ msg->curchunk_len = hdr->msg_len;
	755	+ msg->curchunk_hdrlen = hdrlen;
	756	+
	757	+ /* we have already gotten an somt - don't bother parsing */
	758	+ if (hdr->somt && msg->have_somt)
	759	+ return false;
	760	+
	761	+ if (hdr->somt) {
	762	+ memcpy(&msg->initial_hdr, hdr,
	763	+ sizeof(struct drm_dp_sideband_msg_hdr));
	764	+ msg->have_somt = true;
	765	+ }
	766	+ if (hdr->eomt)
	767	+ msg->have_eomt = true;
	768	+
	769	+ return true;
	770	+}
	771	+
	772	+/* this adds a chunk of msg to the builder to get the final msg */
	773	+static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
	774	+ u8 *replybuf, u8 replybuflen)
	775	+{
327	776	u8 crc4;
328	777
329		- if (hdr) {
330		- u8 hdrlen;
331		- struct drm_dp_sideband_msg_hdr recv_hdr;
332		- ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, replybuflen, &hdrlen);
333		- if (ret == false) {
334		- print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, replybuf, replybuflen, false);
335		- return false;
336		- }
337		-
338		- /*
339		- * ignore out-of-order messages or messages that are part of a
340		- * failed transaction
341		- */
342		- if (!recv_hdr.somt && !msg->have_somt)
343		- return false;
344		-
345		- /* get length contained in this portion */
346		- msg->curchunk_len = recv_hdr.msg_len;
347		- msg->curchunk_hdrlen = hdrlen;
348		-
349		- /* we have already gotten an somt - don't bother parsing */
350		- if (recv_hdr.somt && msg->have_somt)
351		- return false;
352		-
353		- if (recv_hdr.somt) {
354		- memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct drm_dp_sideband_msg_hdr));
355		- msg->have_somt = true;
356		- }
357		- if (recv_hdr.eomt)
358		- msg->have_eomt = true;
359		-
360		- /* copy the bytes for the remainder of this header chunk */
361		- msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
362		- memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
363		- } else {
364		- memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
365		- msg->curchunk_idx += replybuflen;
366		- }
	778	+ memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
	779	+ msg->curchunk_idx += replybuflen;
367	780
368	781	if (msg->curchunk_idx >= msg->curchunk_len) {
369	782	/* do CRC */
370	783	crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
	784	+ if (crc4 != msg->chunk[msg->curchunk_len - 1])
	785	+ print_hex_dump(KERN_DEBUG, "wrong crc",
	786	+ DUMP_PREFIX_NONE, 16, 1,
	787	+ msg->chunk, msg->curchunk_len, false);
371	788	/* copy chunk into bigger msg */
372	789	memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
373	790	msg->curlen += msg->curchunk_len - 1;
..	..	@@ -380,6 +797,7 @@
380	797	{
381	798	int idx = 1;
382	799	int i;
	800	+
383	801	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
384	802	idx += 16;
385	803	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
..	..	@@ -431,6 +849,7 @@
431	849	struct drm_dp_sideband_msg_reply_body *repmsg)
432	850	{
433	851	int idx = 1;
	852	+
434	853	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
435	854	idx++;
436	855	if (idx > raw->curlen)
..	..	@@ -451,6 +870,7 @@
451	870	struct drm_dp_sideband_msg_reply_body *repmsg)
452	871	{
453	872	int idx = 1;
	873	+
454	874	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
455	875	idx++;
456	876	if (idx > raw->curlen)
..	..	@@ -484,6 +904,7 @@
484	904	struct drm_dp_sideband_msg_reply_body *repmsg)
485	905	{
486	906	int idx = 1;
	907	+
487	908	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
488	909	repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
489	910	idx++;
..	..	@@ -507,6 +928,7 @@
507	928	struct drm_dp_sideband_msg_reply_body *repmsg)
508	929	{
509	930	int idx = 1;
	931	+
510	932	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
511	933	idx++;
512	934	if (idx > raw->curlen)
..	..	@@ -529,6 +951,7 @@
529	951	struct drm_dp_sideband_msg_reply_body *repmsg)
530	952	{
531	953	int idx = 1;
	954	+
532	955	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
533	956	idx++;
534	957	if (idx > raw->curlen)
..	..	@@ -558,6 +981,42 @@
558	981	return true;
559	982	}
560	983
	984	+static bool
	985	+drm_dp_sideband_parse_query_stream_enc_status(
	986	+ struct drm_dp_sideband_msg_rx *raw,
	987	+ struct drm_dp_sideband_msg_reply_body *repmsg)
	988	+{
	989	+ struct drm_dp_query_stream_enc_status_ack_reply *reply;
	990	+
	991	+ reply = &repmsg->u.enc_status;
	992	+
	993	+ reply->stream_id = raw->msg[3];
	994	+
	995	+ reply->reply_signed = raw->msg[2] & BIT(0);
	996	+
	997	+ /*
	998	+ * NOTE: It's my impression from reading the spec that the below parsing
	999	+ * is correct. However I noticed while testing with an HDCP 1.4 display
	1000	+ * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
	1001	+ * would expect both bits to be set. So keep the parsing following the
	1002	+ * spec, but beware reality might not match the spec (at least for some
	1003	+ * configurations).
	1004	+ */
	1005	+ reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
	1006	+ reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
	1007	+
	1008	+ reply->query_capable_device_present = raw->msg[2] & BIT(5);
	1009	+ reply->legacy_device_present = raw->msg[2] & BIT(6);
	1010	+ reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
	1011	+
	1012	+ reply->auth_completed = !!(raw->msg[1] & BIT(3));
	1013	+ reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
	1014	+ reply->repeater_present = !!(raw->msg[1] & BIT(5));
	1015	+ reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
	1016	+
	1017	+ return true;
	1018	+}
	1019	+
561	1020	static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
562	1021	struct drm_dp_sideband_msg_reply_body *msg)
563	1022	{
..	..	@@ -565,7 +1024,7 @@
565	1024	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
566	1025	msg->req_type = (raw->msg[0] & 0x7f);
567	1026
568		- if (msg->reply_type) {
	1027	+ if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
569	1028	memcpy(msg->u.nak.guid, &raw->msg[1], 16);
570	1029	msg->u.nak.reason = raw->msg[17];
571	1030	msg->u.nak.nak_data = raw->msg[18];
..	..	@@ -583,6 +1042,8 @@
583	1042	return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
584	1043	case DP_REMOTE_I2C_READ:
585	1044	return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
	1045	+ case DP_REMOTE_I2C_WRITE:
	1046	+ return true; /* since there's nothing to parse */
586	1047	case DP_ENUM_PATH_RESOURCES:
587	1048	return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
588	1049	case DP_ALLOCATE_PAYLOAD:
..	..	@@ -590,8 +1051,13 @@
590	1051	case DP_POWER_DOWN_PHY:
591	1052	case DP_POWER_UP_PHY:
592	1053	return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
	1054	+ case DP_CLEAR_PAYLOAD_ID_TABLE:
	1055	+ return true; /* since there's nothing to parse */
	1056	+ case DP_QUERY_STREAM_ENC_STATUS:
	1057	+ return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
593	1058	default:
594		- DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);
	1059	+ DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
	1060	+ drm_dp_mst_req_type_str(msg->req_type));
595	1061	return false;
596	1062	}
597	1063	}
..	..	@@ -658,12 +1124,14 @@
658	1124	case DP_RESOURCE_STATUS_NOTIFY:
659	1125	return drm_dp_sideband_parse_resource_status_notify(raw, msg);
660	1126	default:
661		- DRM_ERROR("Got unknown request 0x%02x\n", msg->req_type);
	1127	+ DRM_ERROR("Got unknown request 0x%02x (%s)\n", msg->req_type,
	1128	+ drm_dp_mst_req_type_str(msg->req_type));
662	1129	return false;
663	1130	}
664	1131	}
665	1132
666		-static int build_dpcd_write(struct drm_dp_sideband_msg_tx msg, u8 port_num, u32 offset, u8 num_bytes, u8 bytes)
	1133	+static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
	1134	+ u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
667	1135	{
668	1136	struct drm_dp_sideband_msg_req_body req;
669	1137
..	..	@@ -673,20 +1141,27 @@
673	1141	req.u.dpcd_write.num_bytes = num_bytes;
674	1142	req.u.dpcd_write.bytes = bytes;
675	1143	drm_dp_encode_sideband_req(&req, msg);
676		-
677		- return 0;
678	1144	}
679	1145
680		-static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
	1146	+static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
681	1147	{
682	1148	struct drm_dp_sideband_msg_req_body req;
683	1149
684	1150	req.req_type = DP_LINK_ADDRESS;
685	1151	drm_dp_encode_sideband_req(&req, msg);
686		- return 0;
687	1152	}
688	1153
689		-static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
	1154	+static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
	1155	+{
	1156	+ struct drm_dp_sideband_msg_req_body req;
	1157	+
	1158	+ req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
	1159	+ drm_dp_encode_sideband_req(&req, msg);
	1160	+ msg->path_msg = true;
	1161	+}
	1162	+
	1163	+static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
	1164	+ int port_num)
690	1165	{
691	1166	struct drm_dp_sideband_msg_req_body req;
692	1167
..	..	@@ -697,12 +1172,14 @@
697	1172	return 0;
698	1173	}
699	1174
700		-static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
701		- u8 vcpi, uint16_t pbn,
702		- u8 number_sdp_streams,
703		- u8 *sdp_stream_sink)
	1175	+static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
	1176	+ int port_num,
	1177	+ u8 vcpi, uint16_t pbn,
	1178	+ u8 number_sdp_streams,
	1179	+ u8 *sdp_stream_sink)
704	1180	{
705	1181	struct drm_dp_sideband_msg_req_body req;
	1182	+
706	1183	memset(&req, 0, sizeof(req));
707	1184	req.req_type = DP_ALLOCATE_PAYLOAD;
708	1185	req.u.allocate_payload.port_number = port_num;
..	..	@@ -713,11 +1190,10 @@
713	1190	number_sdp_streams);
714	1191	drm_dp_encode_sideband_req(&req, msg);
715	1192	msg->path_msg = true;
716		- return 0;
717	1193	}
718	1194
719		-static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
720		- int port_num, bool power_up)
	1195	+static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
	1196	+ int port_num, bool power_up)
721	1197	{
722	1198	struct drm_dp_sideband_msg_req_body req;
723	1199
..	..	@@ -729,6 +1205,24 @@
729	1205	req.u.port_num.port_number = port_num;
730	1206	drm_dp_encode_sideband_req(&req, msg);
731	1207	msg->path_msg = true;
	1208	+}
	1209	+
	1210	+static int
	1211	+build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
	1212	+ u8 *q_id)
	1213	+{
	1214	+ struct drm_dp_sideband_msg_req_body req;
	1215	+
	1216	+ req.req_type = DP_QUERY_STREAM_ENC_STATUS;
	1217	+ req.u.enc_status.stream_id = stream_id;
	1218	+ memcpy(req.u.enc_status.client_id, q_id,
	1219	+ sizeof(req.u.enc_status.client_id));
	1220	+ req.u.enc_status.stream_event = 0;
	1221	+ req.u.enc_status.valid_stream_event = false;
	1222	+ req.u.enc_status.stream_behavior = 0;
	1223	+ req.u.enc_status.valid_stream_behavior = false;
	1224	+
	1225	+ drm_dp_encode_sideband_req(&req, msg);
732	1226	return 0;
733	1227	}
734	1228
..	..	@@ -765,6 +1259,7 @@
765	1259	int vcpi)
766	1260	{
767	1261	int i;
	1262	+
768	1263	if (vcpi == 0)
769	1264	return;
770	1265
..	..	@@ -773,11 +1268,11 @@
773	1268	clear_bit(vcpi - 1, &mgr->vcpi_mask);
774	1269
775	1270	for (i = 0; i < mgr->max_payloads; i++) {
776		- if (mgr->proposed_vcpis[i])
777		- if (mgr->proposed_vcpis[i]->vcpi == vcpi) {
778		- mgr->proposed_vcpis[i] = NULL;
779		- clear_bit(i + 1, &mgr->payload_mask);
780		- }
	1271	+ if (mgr->proposed_vcpis[i] &&
	1272	+ mgr->proposed_vcpis[i]->vcpi == vcpi) {
	1273	+ mgr->proposed_vcpis[i] = NULL;
	1274	+ clear_bit(i + 1, &mgr->payload_mask);
	1275	+ }
781	1276	}
782	1277	mutex_unlock(&mgr->payload_lock);
783	1278	}
..	..	@@ -801,12 +1296,38 @@
801	1296	struct drm_dp_sideband_msg_tx *txmsg)
802	1297	{
803	1298	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
	1299	+ unsigned long wait_timeout = msecs_to_jiffies(4000);
	1300	+ unsigned long wait_expires = jiffies + wait_timeout;
804	1301	int ret;
805	1302
806		- ret = wait_event_timeout(mgr->tx_waitq,
807		- check_txmsg_state(mgr, txmsg),
808		- (4 * HZ));
809		- mutex_lock(&mstb->mgr->qlock);
	1303	+ for (;;) {
	1304	+ /*
	1305	+ * If the driver provides a way for this, change to
	1306	+ * poll-waiting for the MST reply interrupt if we didn't receive
	1307	+ * it for 50 msec. This would cater for cases where the HPD
	1308	+ * pulse signal got lost somewhere, even though the sink raised
	1309	+ * the corresponding MST interrupt correctly. One example is the
	1310	+ * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
	1311	+ * filters out short pulses with a duration less than ~540 usec.
	1312	+ *
	1313	+ * The poll period is 50 msec to avoid missing an interrupt
	1314	+ * after the sink has cleared it (after a 110msec timeout
	1315	+ * since it raised the interrupt).
	1316	+ */
	1317	+ ret = wait_event_timeout(mgr->tx_waitq,
	1318	+ check_txmsg_state(mgr, txmsg),
	1319	+ mgr->cbs->poll_hpd_irq ?
	1320	+ msecs_to_jiffies(50) :
	1321	+ wait_timeout);
	1322	+
	1323	+ if (ret \|\| !mgr->cbs->poll_hpd_irq \|\|
	1324	+ time_after(jiffies, wait_expires))
	1325	+ break;
	1326	+
	1327	+ mgr->cbs->poll_hpd_irq(mgr);
	1328	+ }
	1329	+
	1330	+ mutex_lock(&mgr->qlock);
810	1331	if (ret > 0) {
811	1332	if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
812	1333	ret = -EIO;
..	..	@@ -820,18 +1341,19 @@
820	1341
821	1342	/* remove from q */
822	1343	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED \|\|
823		- txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
	1344	+ txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND \|\|
	1345	+ txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
824	1346	list_del(&txmsg->next);
825		- }
826		-
827		- if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND \|\|
828		- txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
829		- mstb->tx_slots[txmsg->seqno] = NULL;
830		- }
831	1347	}
832	1348	out:
	1349	+ if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
	1350	+ struct drm_printer p = drm_debug_printer(DBG_PREFIX);
	1351	+
	1352	+ drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
	1353	+ }
833	1354	mutex_unlock(&mgr->qlock);
834	1355
	1356	+ drm_dp_mst_kick_tx(mgr);
835	1357	return ret;
836	1358	}
837	1359
..	..	@@ -847,142 +1369,606 @@
847	1369	if (lct > 1)
848	1370	memcpy(mstb->rad, rad, lct / 2);
849	1371	INIT_LIST_HEAD(&mstb->ports);
850		- kref_init(&mstb->kref);
	1372	+ kref_init(&mstb->topology_kref);
	1373	+ kref_init(&mstb->malloc_kref);
851	1374	return mstb;
852	1375	}
853	1376
854		-static void drm_dp_free_mst_port(struct kref *kref);
855		-
856	1377	static void drm_dp_free_mst_branch_device(struct kref *kref)
857	1378	{
858		- struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
859		- if (mstb->port_parent) {
860		- if (list_empty(&mstb->port_parent->next))
861		- kref_put(&mstb->port_parent->kref, drm_dp_free_mst_port);
862		- }
	1379	+ struct drm_dp_mst_branch *mstb =
	1380	+ container_of(kref, struct drm_dp_mst_branch, malloc_kref);
	1381	+
	1382	+ if (mstb->port_parent)
	1383	+ drm_dp_mst_put_port_malloc(mstb->port_parent);
	1384	+
863	1385	kfree(mstb);
864	1386	}
865	1387
	1388	+/**
	1389	+ * DOC: Branch device and port refcounting
	1390	+ *
	1391	+ * Topology refcount overview
	1392	+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~
	1393	+ *
	1394	+ * The refcounting schemes for &struct drm_dp_mst_branch and &struct
	1395	+ * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
	1396	+ * two different kinds of refcounts: topology refcounts, and malloc refcounts.
	1397	+ *
	1398	+ * Topology refcounts are not exposed to drivers, and are handled internally
	1399	+ * by the DP MST helpers. The helpers use them in order to prevent the
	1400	+ * in-memory topology state from being changed in the middle of critical
	1401	+ * operations like changing the internal state of payload allocations. This
	1402	+ * means each branch and port will be considered to be connected to the rest
	1403	+ * of the topology until its topology refcount reaches zero. Additionally,
	1404	+ * for ports this means that their associated &struct drm_connector will stay
	1405	+ * registered with userspace until the port's refcount reaches 0.
	1406	+ *
	1407	+ * Malloc refcount overview
	1408	+ * ~~~~~~~~~~~~~~~~~~~~~~~~
	1409	+ *
	1410	+ * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
	1411	+ * drm_dp_mst_branch allocated even after all of its topology references have
	1412	+ * been dropped, so that the driver or MST helpers can safely access each
	1413	+ * branch's last known state before it was disconnected from the topology.
	1414	+ * When the malloc refcount of a port or branch reaches 0, the memory
	1415	+ * allocation containing the &struct drm_dp_mst_branch or &struct
	1416	+ * drm_dp_mst_port respectively will be freed.
	1417	+ *
	1418	+ * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
	1419	+ * to drivers. As of writing this documentation, there are no drivers that
	1420	+ * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
	1421	+ * helpers. Exposing this API to drivers in a race-free manner would take more
	1422	+ * tweaking of the refcounting scheme, however patches are welcome provided
	1423	+ * there is a legitimate driver usecase for this.
	1424	+ *
	1425	+ * Refcount relationships in a topology
	1426	+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	1427	+ *
	1428	+ * Let's take a look at why the relationship between topology and malloc
	1429	+ * refcounts is designed the way it is.
	1430	+ *
	1431	+ * .. kernel-figure:: dp-mst/topology-figure-1.dot
	1432	+ *
	1433	+ * An example of topology and malloc refs in a DP MST topology with two
	1434	+ * active payloads. Topology refcount increments are indicated by solid
	1435	+ * lines, and malloc refcount increments are indicated by dashed lines.
	1436	+ * Each starts from the branch which incremented the refcount, and ends at
	1437	+ * the branch to which the refcount belongs to, i.e. the arrow points the
	1438	+ * same way as the C pointers used to reference a structure.
	1439	+ *
	1440	+ * As you can see in the above figure, every branch increments the topology
	1441	+ * refcount of its children, and increments the malloc refcount of its
	1442	+ * parent. Additionally, every payload increments the malloc refcount of its
	1443	+ * assigned port by 1.
	1444	+ *
	1445	+ * So, what would happen if MSTB #3 from the above figure was unplugged from
	1446	+ * the system, but the driver hadn't yet removed payload #2 from port #3? The
	1447	+ * topology would start to look like the figure below.
	1448	+ *
	1449	+ * .. kernel-figure:: dp-mst/topology-figure-2.dot
	1450	+ *
	1451	+ * Ports and branch devices which have been released from memory are
	1452	+ * colored grey, and references which have been removed are colored red.
	1453	+ *
	1454	+ * Whenever a port or branch device's topology refcount reaches zero, it will
	1455	+ * decrement the topology refcounts of all its children, the malloc refcount
	1456	+ * of its parent, and finally its own malloc refcount. For MSTB #4 and port
	1457	+ * #4, this means they both have been disconnected from the topology and freed
	1458	+ * from memory. But, because payload #2 is still holding a reference to port
	1459	+ * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
	1460	+ * is still accessible from memory. This also means port #3 has not yet
	1461	+ * decremented the malloc refcount of MSTB #3, so its &struct
	1462	+ * drm_dp_mst_branch will also stay allocated in memory until port #3's
	1463	+ * malloc refcount reaches 0.
	1464	+ *
	1465	+ * This relationship is necessary because in order to release payload #2, we
	1466	+ * need to be able to figure out the last relative of port #3 that's still
	1467	+ * connected to the topology. In this case, we would travel up the topology as
	1468	+ * shown below.
	1469	+ *
	1470	+ * .. kernel-figure:: dp-mst/topology-figure-3.dot
	1471	+ *
	1472	+ * And finally, remove payload #2 by communicating with port #2 through
	1473	+ * sideband transactions.
	1474	+ */
	1475	+
	1476	+/**
	1477	+ * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
	1478	+ * device
	1479	+ * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
	1480	+ *
	1481	+ * Increments &drm_dp_mst_branch.malloc_kref. When
	1482	+ * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
	1483	+ * will be released and @mstb may no longer be used.
	1484	+ *
	1485	+ * See also: drm_dp_mst_put_mstb_malloc()
	1486	+ */
	1487	+static void
	1488	+drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
	1489	+{
	1490	+ kref_get(&mstb->malloc_kref);
	1491	+ DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
	1492	+}
	1493	+
	1494	+/**
	1495	+ * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
	1496	+ * device
	1497	+ * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
	1498	+ *
	1499	+ * Decrements &drm_dp_mst_branch.malloc_kref. When
	1500	+ * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
	1501	+ * will be released and @mstb may no longer be used.
	1502	+ *
	1503	+ * See also: drm_dp_mst_get_mstb_malloc()
	1504	+ */
	1505	+static void
	1506	+drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
	1507	+{
	1508	+ DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
	1509	+ kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
	1510	+}
	1511	+
	1512	+static void drm_dp_free_mst_port(struct kref *kref)
	1513	+{
	1514	+ struct drm_dp_mst_port *port =
	1515	+ container_of(kref, struct drm_dp_mst_port, malloc_kref);
	1516	+
	1517	+ drm_dp_mst_put_mstb_malloc(port->parent);
	1518	+ kfree(port);
	1519	+}
	1520	+
	1521	+/**
	1522	+ * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
	1523	+ * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
	1524	+ *
	1525	+ * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
	1526	+ * reaches 0, the memory allocation for @port will be released and @port may
	1527	+ * no longer be used.
	1528	+ *
	1529	+ * Because @port could potentially be freed at any time by the DP MST helpers
	1530	+ * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
	1531	+ * function, drivers that which to make use of &struct drm_dp_mst_port should
	1532	+ * ensure that they grab at least one main malloc reference to their MST ports
	1533	+ * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
	1534	+ * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
	1535	+ *
	1536	+ * See also: drm_dp_mst_put_port_malloc()
	1537	+ */
	1538	+void
	1539	+drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
	1540	+{
	1541	+ kref_get(&port->malloc_kref);
	1542	+ DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref));
	1543	+}
	1544	+EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
	1545	+
	1546	+/**
	1547	+ * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
	1548	+ * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
	1549	+ *
	1550	+ * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
	1551	+ * reaches 0, the memory allocation for @port will be released and @port may
	1552	+ * no longer be used.
	1553	+ *
	1554	+ * See also: drm_dp_mst_get_port_malloc()
	1555	+ */
	1556	+void
	1557	+drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
	1558	+{
	1559	+ DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
	1560	+ kref_put(&port->malloc_kref, drm_dp_free_mst_port);
	1561	+}
	1562	+EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
	1563	+
	1564	+#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	1565	+
	1566	+#define STACK_DEPTH 8
	1567	+
	1568	+static noinline void
	1569	+__topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
	1570	+ struct drm_dp_mst_topology_ref_history *history,
	1571	+ enum drm_dp_mst_topology_ref_type type)
	1572	+{
	1573	+ struct drm_dp_mst_topology_ref_entry *entry = NULL;
	1574	+ depot_stack_handle_t backtrace;
	1575	+ ulong stack_entries[STACK_DEPTH];
	1576	+ uint n;
	1577	+ int i;
	1578	+
	1579	+ n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
	1580	+ backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
	1581	+ if (!backtrace)
	1582	+ return;
	1583	+
	1584	+ /* Try to find an existing entry for this backtrace */
	1585	+ for (i = 0; i < history->len; i++) {
	1586	+ if (history->entries[i].backtrace == backtrace) {
	1587	+ entry = &history->entries[i];
	1588	+ break;
	1589	+ }
	1590	+ }
	1591	+
	1592	+ /* Otherwise add one */
	1593	+ if (!entry) {
	1594	+ struct drm_dp_mst_topology_ref_entry *new;
	1595	+ int new_len = history->len + 1;
	1596	+
	1597	+ new = krealloc(history->entries, sizeof(new) new_len,
	1598	+ GFP_KERNEL);
	1599	+ if (!new)
	1600	+ return;
	1601	+
	1602	+ entry = &new[history->len];
	1603	+ history->len = new_len;
	1604	+ history->entries = new;
	1605	+
	1606	+ entry->backtrace = backtrace;
	1607	+ entry->type = type;
	1608	+ entry->count = 0;
	1609	+ }
	1610	+ entry->count++;
	1611	+ entry->ts_nsec = ktime_get_ns();
	1612	+}
	1613	+
	1614	+static int
	1615	+topology_ref_history_cmp(const void a, const void b)
	1616	+{
	1617	+ const struct drm_dp_mst_topology_ref_entry entry_a = a, entry_b = b;
	1618	+
	1619	+ if (entry_a->ts_nsec > entry_b->ts_nsec)
	1620	+ return 1;
	1621	+ else if (entry_a->ts_nsec < entry_b->ts_nsec)
	1622	+ return -1;
	1623	+ else
	1624	+ return 0;
	1625	+}
	1626	+
	1627	+static inline const char *
	1628	+topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
	1629	+{
	1630	+ if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
	1631	+ return "get";
	1632	+ else
	1633	+ return "put";
	1634	+}
	1635	+
	1636	+static void
	1637	+__dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
	1638	+ void ptr, const char type_str)
	1639	+{
	1640	+ struct drm_printer p = drm_debug_printer(DBG_PREFIX);
	1641	+ char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	1642	+ int i;
	1643	+
	1644	+ if (!buf)
	1645	+ return;
	1646	+
	1647	+ if (!history->len)
	1648	+ goto out;
	1649	+
	1650	+ /* First, sort the list so that it goes from oldest to newest
	1651	+ * reference entry
	1652	+ */
	1653	+ sort(history->entries, history->len, sizeof(*history->entries),
	1654	+ topology_ref_history_cmp, NULL);
	1655	+
	1656	+ drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
	1657	+ type_str, ptr);
	1658	+
	1659	+ for (i = 0; i < history->len; i++) {
	1660	+ const struct drm_dp_mst_topology_ref_entry *entry =
	1661	+ &history->entries[i];
	1662	+ ulong *entries;
	1663	+ uint nr_entries;
	1664	+ u64 ts_nsec = entry->ts_nsec;
	1665	+ u32 rem_nsec = do_div(ts_nsec, 1000000000);
	1666	+
	1667	+ nr_entries = stack_depot_fetch(entry->backtrace, &entries);
	1668	+ stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
	1669	+
	1670	+ drm_printf(&p, " %d %ss (last at %5llu.%06u):\n%s",
	1671	+ entry->count,
	1672	+ topology_ref_type_to_str(entry->type),
	1673	+ ts_nsec, rem_nsec / 1000, buf);
	1674	+ }
	1675	+
	1676	+ /* Now free the history, since this is the only time we expose it */
	1677	+ kfree(history->entries);
	1678	+out:
	1679	+ kfree(buf);
	1680	+}
	1681	+
	1682	+static __always_inline void
	1683	+drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
	1684	+{
	1685	+ __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
	1686	+ "MSTB");
	1687	+}
	1688	+
	1689	+static __always_inline void
	1690	+drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
	1691	+{
	1692	+ __dump_topology_ref_history(&port->topology_ref_history, port,
	1693	+ "Port");
	1694	+}
	1695	+
	1696	+static __always_inline void
	1697	+save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
	1698	+ enum drm_dp_mst_topology_ref_type type)
	1699	+{
	1700	+ __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
	1701	+}
	1702	+
	1703	+static __always_inline void
	1704	+save_port_topology_ref(struct drm_dp_mst_port *port,
	1705	+ enum drm_dp_mst_topology_ref_type type)
	1706	+{
	1707	+ __topology_ref_save(port->mgr, &port->topology_ref_history, type);
	1708	+}
	1709	+
	1710	+static inline void
	1711	+topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
	1712	+{
	1713	+ mutex_lock(&mgr->topology_ref_history_lock);
	1714	+}
	1715	+
	1716	+static inline void
	1717	+topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
	1718	+{
	1719	+ mutex_unlock(&mgr->topology_ref_history_lock);
	1720	+}
	1721	+#else
	1722	+static inline void
	1723	+topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
	1724	+static inline void
	1725	+topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
	1726	+static inline void
	1727	+drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
	1728	+static inline void
	1729	+drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
	1730	+#define save_mstb_topology_ref(mstb, type)
	1731	+#define save_port_topology_ref(port, type)
	1732	+#endif
	1733	+
866	1734	static void drm_dp_destroy_mst_branch_device(struct kref *kref)
867	1735	{
868		- struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
869		- struct drm_dp_mst_port port, tmp;
870		- bool wake_tx = false;
	1736	+ struct drm_dp_mst_branch *mstb =
	1737	+ container_of(kref, struct drm_dp_mst_branch, topology_kref);
	1738	+ struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
	1739	+
	1740	+ drm_dp_mst_dump_mstb_topology_history(mstb);
	1741	+
	1742	+ INIT_LIST_HEAD(&mstb->destroy_next);
871	1743
872	1744	/*
873		- * init kref again to be used by ports to remove mst branch when it is
874		- * not needed anymore
	1745	+ * This can get called under mgr->mutex, so we need to perform the
	1746	+ * actual destruction of the mstb in another worker
875	1747	*/
876		- kref_init(kref);
877		-
878		- if (mstb->port_parent && list_empty(&mstb->port_parent->next))
879		- kref_get(&mstb->port_parent->kref);
880		-
881		- /*
882		- * destroy all ports - don't need lock
883		- * as there are no more references to the mst branch
884		- * device at this point.
885		- */
886		- list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
887		- list_del(&port->next);
888		- drm_dp_put_port(port);
889		- }
890		-
891		- /* drop any tx slots msg */
892		- mutex_lock(&mstb->mgr->qlock);
893		- if (mstb->tx_slots[0]) {
894		- mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
895		- mstb->tx_slots[0] = NULL;
896		- wake_tx = true;
897		- }
898		- if (mstb->tx_slots[1]) {
899		- mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
900		- mstb->tx_slots[1] = NULL;
901		- wake_tx = true;
902		- }
903		- mutex_unlock(&mstb->mgr->qlock);
904		-
905		- if (wake_tx)
906		- wake_up_all(&mstb->mgr->tx_waitq);
907		-
908		- kref_put(kref, drm_dp_free_mst_branch_device);
	1748	+ mutex_lock(&mgr->delayed_destroy_lock);
	1749	+ list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
	1750	+ mutex_unlock(&mgr->delayed_destroy_lock);
	1751	+ queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
909	1752	}
910	1753
911		-static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
	1754	+/**
	1755	+ * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
	1756	+ * branch device unless it's zero
	1757	+ * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
	1758	+ *
	1759	+ * Attempts to grab a topology reference to @mstb, if it hasn't yet been
	1760	+ * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
	1761	+ * reached 0). Holding a topology reference implies that a malloc reference
	1762	+ * will be held to @mstb as long as the user holds the topology reference.
	1763	+ *
	1764	+ * Care should be taken to ensure that the user has at least one malloc
	1765	+ * reference to @mstb. If you already have a topology reference to @mstb, you
	1766	+ * should use drm_dp_mst_topology_get_mstb() instead.
	1767	+ *
	1768	+ * See also:
	1769	+ * drm_dp_mst_topology_get_mstb()
	1770	+ * drm_dp_mst_topology_put_mstb()
	1771	+ *
	1772	+ * Returns:
	1773	+ * * 1: A topology reference was grabbed successfully
	1774	+ * * 0: @port is no longer in the topology, no reference was grabbed
	1775	+ */
	1776	+static int __must_check
	1777	+drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
912	1778	{
913		- kref_put(&mstb->kref, drm_dp_destroy_mst_branch_device);
	1779	+ int ret;
	1780	+
	1781	+ topology_ref_history_lock(mstb->mgr);
	1782	+ ret = kref_get_unless_zero(&mstb->topology_kref);
	1783	+ if (ret) {
	1784	+ DRM_DEBUG("mstb %p (%d)\n",
	1785	+ mstb, kref_read(&mstb->topology_kref));
	1786	+ save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
	1787	+ }
	1788	+
	1789	+ topology_ref_history_unlock(mstb->mgr);
	1790	+
	1791	+ return ret;
914	1792	}
915	1793
916		-
917		-static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, int old_pdt)
	1794	+/**
	1795	+ * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
	1796	+ * branch device
	1797	+ * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
	1798	+ *
	1799	+ * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
	1800	+ * not it's already reached 0. This is only valid to use in scenarios where
	1801	+ * you are already guaranteed to have at least one active topology reference
	1802	+ * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
	1803	+ *
	1804	+ * See also:
	1805	+ * drm_dp_mst_topology_try_get_mstb()
	1806	+ * drm_dp_mst_topology_put_mstb()
	1807	+ */
	1808	+static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
918	1809	{
919		- struct drm_dp_mst_branch *mstb;
	1810	+ topology_ref_history_lock(mstb->mgr);
920	1811
921		- switch (old_pdt) {
922		- case DP_PEER_DEVICE_DP_LEGACY_CONV:
923		- case DP_PEER_DEVICE_SST_SINK:
924		- /* remove i2c over sideband */
925		- drm_dp_mst_unregister_i2c_bus(&port->aux);
926		- break;
927		- case DP_PEER_DEVICE_MST_BRANCHING:
928		- mstb = port->mstb;
929		- port->mstb = NULL;
930		- drm_dp_put_mst_branch_device(mstb);
931		- break;
932		- }
	1812	+ save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
	1813	+ WARN_ON(kref_read(&mstb->topology_kref) == 0);
	1814	+ kref_get(&mstb->topology_kref);
	1815	+ DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
	1816	+
	1817	+ topology_ref_history_unlock(mstb->mgr);
	1818	+}
	1819	+
	1820	+/**
	1821	+ * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
	1822	+ * device
	1823	+ * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
	1824	+ *
	1825	+ * Releases a topology reference from @mstb by decrementing
	1826	+ * &drm_dp_mst_branch.topology_kref.
	1827	+ *
	1828	+ * See also:
	1829	+ * drm_dp_mst_topology_try_get_mstb()
	1830	+ * drm_dp_mst_topology_get_mstb()
	1831	+ */
	1832	+static void
	1833	+drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
	1834	+{
	1835	+ topology_ref_history_lock(mstb->mgr);
	1836	+
	1837	+ DRM_DEBUG("mstb %p (%d)\n",
	1838	+ mstb, kref_read(&mstb->topology_kref) - 1);
	1839	+ save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
	1840	+
	1841	+ topology_ref_history_unlock(mstb->mgr);
	1842	+ kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
933	1843	}
934	1844
935	1845	static void drm_dp_destroy_port(struct kref *kref)
936	1846	{
937		- struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
	1847	+ struct drm_dp_mst_port *port =
	1848	+ container_of(kref, struct drm_dp_mst_port, topology_kref);
938	1849	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
939	1850
940		- if (!port->input) {
941		- port->vcpi.num_slots = 0;
	1851	+ drm_dp_mst_dump_port_topology_history(port);
942	1852
943		- kfree(port->cached_edid);
944		-
945		- /*
946		- * The only time we don't have a connector
947		- * on an output port is if the connector init
948		- * fails.
949		- */
950		- if (port->connector) {
951		- /* we can't destroy the connector here, as
952		- * we might be holding the mode_config.mutex
953		- * from an EDID retrieval */
954		-
955		- mutex_lock(&mgr->destroy_connector_lock);
956		- kref_get(&port->parent->kref);
957		- list_add(&port->next, &mgr->destroy_connector_list);
958		- mutex_unlock(&mgr->destroy_connector_lock);
959		- schedule_work(&mgr->destroy_connector_work);
960		- return;
961		- }
962		- /* no need to clean up vcpi
963		- * as if we have no connector we never setup a vcpi */
964		- drm_dp_port_teardown_pdt(port, port->pdt);
965		- port->pdt = DP_PEER_DEVICE_NONE;
	1853	+ /* There's nothing that needs locking to destroy an input port yet */
	1854	+ if (port->input) {
	1855	+ drm_dp_mst_put_port_malloc(port);
	1856	+ return;
966	1857	}
967		- kfree(port);
	1858	+
	1859	+ kfree(port->cached_edid);
	1860	+
	1861	+ /*
	1862	+ * we can't destroy the connector here, as we might be holding the
	1863	+ * mode_config.mutex from an EDID retrieval
	1864	+ */
	1865	+ mutex_lock(&mgr->delayed_destroy_lock);
	1866	+ list_add(&port->next, &mgr->destroy_port_list);
	1867	+ mutex_unlock(&mgr->delayed_destroy_lock);
	1868	+ queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
968	1869	}
969	1870
970		-static void drm_dp_put_port(struct drm_dp_mst_port *port)
	1871	+/**
	1872	+ * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
	1873	+ * port unless it's zero
	1874	+ * @port: &struct drm_dp_mst_port to increment the topology refcount of
	1875	+ *
	1876	+ * Attempts to grab a topology reference to @port, if it hasn't yet been
	1877	+ * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
	1878	+ * 0). Holding a topology reference implies that a malloc reference will be
	1879	+ * held to @port as long as the user holds the topology reference.
	1880	+ *
	1881	+ * Care should be taken to ensure that the user has at least one malloc
	1882	+ * reference to @port. If you already have a topology reference to @port, you
	1883	+ * should use drm_dp_mst_topology_get_port() instead.
	1884	+ *
	1885	+ * See also:
	1886	+ * drm_dp_mst_topology_get_port()
	1887	+ * drm_dp_mst_topology_put_port()
	1888	+ *
	1889	+ * Returns:
	1890	+ * * 1: A topology reference was grabbed successfully
	1891	+ * * 0: @port is no longer in the topology, no reference was grabbed
	1892	+ */
	1893	+static int __must_check
	1894	+drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
971	1895	{
972		- kref_put(&port->kref, drm_dp_destroy_port);
	1896	+ int ret;
	1897	+
	1898	+ topology_ref_history_lock(port->mgr);
	1899	+ ret = kref_get_unless_zero(&port->topology_kref);
	1900	+ if (ret) {
	1901	+ DRM_DEBUG("port %p (%d)\n",
	1902	+ port, kref_read(&port->topology_kref));
	1903	+ save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
	1904	+ }
	1905	+
	1906	+ topology_ref_history_unlock(port->mgr);
	1907	+ return ret;
973	1908	}
974	1909
975		-static struct drm_dp_mst_branch drm_dp_mst_get_validated_mstb_ref_locked(struct drm_dp_mst_branch mstb, struct drm_dp_mst_branch *to_find)
	1910	+/**
	1911	+ * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
	1912	+ * @port: The &struct drm_dp_mst_port to increment the topology refcount of
	1913	+ *
	1914	+ * Increments &drm_dp_mst_port.topology_refcount without checking whether or
	1915	+ * not it's already reached 0. This is only valid to use in scenarios where
	1916	+ * you are already guaranteed to have at least one active topology reference
	1917	+ * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
	1918	+ *
	1919	+ * See also:
	1920	+ * drm_dp_mst_topology_try_get_port()
	1921	+ * drm_dp_mst_topology_put_port()
	1922	+ */
	1923	+static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
	1924	+{
	1925	+ topology_ref_history_lock(port->mgr);
	1926	+
	1927	+ WARN_ON(kref_read(&port->topology_kref) == 0);
	1928	+ kref_get(&port->topology_kref);
	1929	+ DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->topology_kref));
	1930	+ save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
	1931	+
	1932	+ topology_ref_history_unlock(port->mgr);
	1933	+}
	1934	+
	1935	+/**
	1936	+ * drm_dp_mst_topology_put_port() - release a topology reference to a port
	1937	+ * @port: The &struct drm_dp_mst_port to release the topology reference from
	1938	+ *
	1939	+ * Releases a topology reference from @port by decrementing
	1940	+ * &drm_dp_mst_port.topology_kref.
	1941	+ *
	1942	+ * See also:
	1943	+ * drm_dp_mst_topology_try_get_port()
	1944	+ * drm_dp_mst_topology_get_port()
	1945	+ */
	1946	+static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
	1947	+{
	1948	+ topology_ref_history_lock(port->mgr);
	1949	+
	1950	+ DRM_DEBUG("port %p (%d)\n",
	1951	+ port, kref_read(&port->topology_kref) - 1);
	1952	+ save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
	1953	+
	1954	+ topology_ref_history_unlock(port->mgr);
	1955	+ kref_put(&port->topology_kref, drm_dp_destroy_port);
	1956	+}
	1957	+
	1958	+static struct drm_dp_mst_branch *
	1959	+drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
	1960	+ struct drm_dp_mst_branch *to_find)
976	1961	{
977	1962	struct drm_dp_mst_port *port;
978	1963	struct drm_dp_mst_branch *rmstb;
979		- if (to_find == mstb) {
980		- kref_get(&mstb->kref);
	1964	+
	1965	+ if (to_find == mstb)
981	1966	return mstb;
982		- }
	1967	+
983	1968	list_for_each_entry(port, &mstb->ports, next) {
984	1969	if (port->mstb) {
985		- rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
	1970	+ rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
	1971	+ port->mstb, to_find);
986	1972	if (rmstb)
987	1973	return rmstb;
988	1974	}
..	..	@@ -990,27 +1976,37 @@
990	1976	return NULL;
991	1977	}
992	1978
993		-static struct drm_dp_mst_branch drm_dp_get_validated_mstb_ref(struct drm_dp_mst_topology_mgr mgr, struct drm_dp_mst_branch *mstb)
	1979	+static struct drm_dp_mst_branch *
	1980	+drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
	1981	+ struct drm_dp_mst_branch *mstb)
994	1982	{
995	1983	struct drm_dp_mst_branch *rmstb = NULL;
	1984	+
996	1985	mutex_lock(&mgr->lock);
997		- if (mgr->mst_primary)
998		- rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, mstb);
	1986	+ if (mgr->mst_primary) {
	1987	+ rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
	1988	+ mgr->mst_primary, mstb);
	1989	+
	1990	+ if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
	1991	+ rmstb = NULL;
	1992	+ }
999	1993	mutex_unlock(&mgr->lock);
1000	1994	return rmstb;
1001	1995	}
1002	1996
1003		-static struct drm_dp_mst_port drm_dp_mst_get_port_ref_locked(struct drm_dp_mst_branch mstb, struct drm_dp_mst_port *to_find)
	1997	+static struct drm_dp_mst_port *
	1998	+drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
	1999	+ struct drm_dp_mst_port *to_find)
1004	2000	{
1005	2001	struct drm_dp_mst_port port, mport;
1006	2002
1007	2003	list_for_each_entry(port, &mstb->ports, next) {
1008		- if (port == to_find) {
1009		- kref_get(&port->kref);
	2004	+ if (port == to_find)
1010	2005	return port;
1011		- }
	2006	+
1012	2007	if (port->mstb) {
1013		- mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
	2008	+ mport = drm_dp_mst_topology_get_port_validated_locked(
	2009	+ port->mstb, to_find);
1014	2010	if (mport)
1015	2011	return mport;
1016	2012	}
..	..	@@ -1018,12 +2014,20 @@
1018	2014	return NULL;
1019	2015	}
1020	2016
1021		-static struct drm_dp_mst_port drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr mgr, struct drm_dp_mst_port *port)
	2017	+static struct drm_dp_mst_port *
	2018	+drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
	2019	+ struct drm_dp_mst_port *port)
1022	2020	{
1023	2021	struct drm_dp_mst_port *rport = NULL;
	2022	+
1024	2023	mutex_lock(&mgr->lock);
1025		- if (mgr->mst_primary)
1026		- rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
	2024	+ if (mgr->mst_primary) {
	2025	+ rport = drm_dp_mst_topology_get_port_validated_locked(
	2026	+ mgr->mst_primary, port);
	2027	+
	2028	+ if (rport && !drm_dp_mst_topology_try_get_port(rport))
	2029	+ rport = NULL;
	2030	+ }
1027	2031	mutex_unlock(&mgr->lock);
1028	2032	return rport;
1029	2033	}
..	..	@@ -1031,11 +2035,12 @@
1031	2035	static struct drm_dp_mst_port drm_dp_get_port(struct drm_dp_mst_branch mstb, u8 port_num)
1032	2036	{
1033	2037	struct drm_dp_mst_port *port;
	2038	+ int ret;
1034	2039
1035	2040	list_for_each_entry(port, &mstb->ports, next) {
1036	2041	if (port->port_num == port_num) {
1037		- kref_get(&port->kref);
1038		- return port;
	2042	+ ret = drm_dp_mst_topology_try_get_port(port);
	2043	+ return ret ? port : NULL;
1039	2044	}
1040	2045	}
1041	2046
..	..	@@ -1053,6 +2058,7 @@
1053	2058	int parent_lct = port->parent->lct;
1054	2059	int shift = 4;
1055	2060	int idx = (parent_lct - 1) / 2;
	2061	+
1056	2062	if (parent_lct > 1) {
1057	2063	memcpy(rad, port->parent->rad, idx + 1);
1058	2064	shift = (parent_lct % 2) ? 4 : 0;
..	..	@@ -1063,58 +2069,165 @@
1063	2069	return parent_lct + 1;
1064	2070	}
1065	2071
1066		-/*
1067		- * return sends link address for new mstb
1068		- */
1069		-static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
	2072	+static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
1070	2073	{
1071		- int ret;
1072		- u8 rad[6], lct;
1073		- bool send_link = false;
1074		- switch (port->pdt) {
	2074	+ switch (pdt) {
1075	2075	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1076	2076	case DP_PEER_DEVICE_SST_SINK:
1077		- /* add i2c over sideband */
1078		- ret = drm_dp_mst_register_i2c_bus(&port->aux);
1079		- break;
	2077	+ return true;
1080	2078	case DP_PEER_DEVICE_MST_BRANCHING:
1081		- lct = drm_dp_calculate_rad(port, rad);
	2079	+ /* For sst branch device */
	2080	+ if (!mcs)
	2081	+ return true;
1082	2082
1083		- port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1084		- if (port->mstb) {
1085		- port->mstb->mgr = port->mgr;
1086		- port->mstb->port_parent = port;
1087		-
1088		- send_link = true;
1089		- }
1090		- break;
	2083	+ return false;
1091	2084	}
1092		- return send_link;
	2085	+ return true;
1093	2086	}
1094	2087
1095		-static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch mstb, u8 guid)
	2088	+static int
	2089	+drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
	2090	+ bool new_mcs)
1096	2091	{
1097		- int ret;
	2092	+ struct drm_dp_mst_topology_mgr *mgr = port->mgr;
	2093	+ struct drm_dp_mst_branch *mstb;
	2094	+ u8 rad[8], lct;
	2095	+ int ret = 0;
	2096	+
	2097	+ if (port->pdt == new_pdt && port->mcs == new_mcs)
	2098	+ return 0;
	2099	+
	2100	+ /* Teardown the old pdt, if there is one */
	2101	+ if (port->pdt != DP_PEER_DEVICE_NONE) {
	2102	+ if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
	2103	+ /*
	2104	+ * If the new PDT would also have an i2c bus,
	2105	+ * don't bother with reregistering it
	2106	+ */
	2107	+ if (new_pdt != DP_PEER_DEVICE_NONE &&
	2108	+ drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
	2109	+ port->pdt = new_pdt;
	2110	+ port->mcs = new_mcs;
	2111	+ return 0;
	2112	+ }
	2113	+
	2114	+ /* remove i2c over sideband */
	2115	+ drm_dp_mst_unregister_i2c_bus(port);
	2116	+ } else {
	2117	+ mutex_lock(&mgr->lock);
	2118	+ drm_dp_mst_topology_put_mstb(port->mstb);
	2119	+ port->mstb = NULL;
	2120	+ mutex_unlock(&mgr->lock);
	2121	+ }
	2122	+ }
	2123	+
	2124	+ port->pdt = new_pdt;
	2125	+ port->mcs = new_mcs;
	2126	+
	2127	+ if (port->pdt != DP_PEER_DEVICE_NONE) {
	2128	+ if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
	2129	+ /* add i2c over sideband */
	2130	+ ret = drm_dp_mst_register_i2c_bus(port);
	2131	+ } else {
	2132	+ lct = drm_dp_calculate_rad(port, rad);
	2133	+ mstb = drm_dp_add_mst_branch_device(lct, rad);
	2134	+ if (!mstb) {
	2135	+ ret = -ENOMEM;
	2136	+ DRM_ERROR("Failed to create MSTB for port %p",
	2137	+ port);
	2138	+ goto out;
	2139	+ }
	2140	+
	2141	+ mutex_lock(&mgr->lock);
	2142	+ port->mstb = mstb;
	2143	+ mstb->mgr = port->mgr;
	2144	+ mstb->port_parent = port;
	2145	+
	2146	+ /*
	2147	+ * Make sure this port's memory allocation stays
	2148	+ * around until its child MSTB releases it
	2149	+ */
	2150	+ drm_dp_mst_get_port_malloc(port);
	2151	+ mutex_unlock(&mgr->lock);
	2152	+
	2153	+ /* And make sure we send a link address for this */
	2154	+ ret = 1;
	2155	+ }
	2156	+ }
	2157	+
	2158	+out:
	2159	+ if (ret < 0)
	2160	+ port->pdt = DP_PEER_DEVICE_NONE;
	2161	+ return ret;
	2162	+}
	2163	+
	2164	+/**
	2165	+ * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
	2166	+ * @aux: Fake sideband AUX CH
	2167	+ * @offset: address of the (first) register to read
	2168	+ * @buffer: buffer to store the register values
	2169	+ * @size: number of bytes in @buffer
	2170	+ *
	2171	+ * Performs the same functionality for remote devices via
	2172	+ * sideband messaging as drm_dp_dpcd_read() does for local
	2173	+ * devices via actual AUX CH.
	2174	+ *
	2175	+ * Return: Number of bytes read, or negative error code on failure.
	2176	+ */
	2177	+ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
	2178	+ unsigned int offset, void *buffer, size_t size)
	2179	+{
	2180	+ struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
	2181	+ aux);
	2182	+
	2183	+ return drm_dp_send_dpcd_read(port->mgr, port,
	2184	+ offset, size, buffer);
	2185	+}
	2186	+
	2187	+/**
	2188	+ * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
	2189	+ * @aux: Fake sideband AUX CH
	2190	+ * @offset: address of the (first) register to write
	2191	+ * @buffer: buffer containing the values to write
	2192	+ * @size: number of bytes in @buffer
	2193	+ *
	2194	+ * Performs the same functionality for remote devices via
	2195	+ * sideband messaging as drm_dp_dpcd_write() does for local
	2196	+ * devices via actual AUX CH.
	2197	+ *
	2198	+ * Return: number of bytes written on success, negative error code on failure.
	2199	+ */
	2200	+ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
	2201	+ unsigned int offset, void *buffer, size_t size)
	2202	+{
	2203	+ struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
	2204	+ aux);
	2205	+
	2206	+ return drm_dp_send_dpcd_write(port->mgr, port,
	2207	+ offset, size, buffer);
	2208	+}
	2209	+
	2210	+static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch mstb, u8 guid)
	2211	+{
	2212	+ int ret = 0;
1098	2213
1099	2214	memcpy(mstb->guid, guid, 16);
1100	2215
1101	2216	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
1102	2217	if (mstb->port_parent) {
1103		- ret = drm_dp_send_dpcd_write(
1104		- mstb->mgr,
1105		- mstb->port_parent,
1106		- DP_GUID,
1107		- 16,
1108		- mstb->guid);
	2218	+ ret = drm_dp_send_dpcd_write(mstb->mgr,
	2219	+ mstb->port_parent,
	2220	+ DP_GUID, 16, mstb->guid);
1109	2221	} else {
1110		-
1111		- ret = drm_dp_dpcd_write(
1112		- mstb->mgr->aux,
1113		- DP_GUID,
1114		- mstb->guid,
1115		- 16);
	2222	+ ret = drm_dp_dpcd_write(mstb->mgr->aux,
	2223	+ DP_GUID, mstb->guid, 16);
1116	2224	}
1117	2225	}
	2226	+
	2227	+ if (ret < 16 && ret > 0)
	2228	+ return -EPROTO;
	2229	+
	2230	+ return ret == 16 ? 0 : ret;
1118	2231	}
1119	2232
1120	2233	static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
..	..	@@ -1124,10 +2237,12 @@
1124	2237	{
1125	2238	int i;
1126	2239	char temp[8];
	2240	+
1127	2241	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1128	2242	for (i = 0; i < (mstb->lct - 1); i++) {
1129	2243	int shift = (i % 2) ? 0 : 4;
1130	2244	int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
	2245	+
1131	2246	snprintf(temp, sizeof(temp), "-%d", port_num);
1132	2247	strlcat(proppath, temp, proppath_size);
1133	2248	}
..	..	@@ -1135,35 +2250,177 @@
1135	2250	strlcat(proppath, temp, proppath_size);
1136	2251	}
1137	2252
1138		-static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1139		- struct drm_device *dev,
1140		- struct drm_dp_link_addr_reply_port *port_msg)
	2253	+/**
	2254	+ * drm_dp_mst_connector_late_register() - Late MST connector registration
	2255	+ * @connector: The MST connector
	2256	+ * @port: The MST port for this connector
	2257	+ *
	2258	+ * Helper to register the remote aux device for this MST port. Drivers should
	2259	+ * call this from their mst connector's late_register hook to enable MST aux
	2260	+ * devices.
	2261	+ *
	2262	+ * Return: 0 on success, negative error code on failure.
	2263	+ */
	2264	+int drm_dp_mst_connector_late_register(struct drm_connector *connector,
	2265	+ struct drm_dp_mst_port *port)
1141	2266	{
1142		- struct drm_dp_mst_port *port;
1143		- bool ret;
1144		- bool created = false;
1145		- int old_pdt = 0;
1146		- int old_ddps = 0;
1147		- port = drm_dp_get_port(mstb, port_msg->port_number);
1148		- if (!port) {
1149		- port = kzalloc(sizeof(*port), GFP_KERNEL);
1150		- if (!port)
1151		- return;
1152		- kref_init(&port->kref);
1153		- port->parent = mstb;
1154		- port->port_num = port_msg->port_number;
1155		- port->mgr = mstb->mgr;
1156		- port->aux.name = "DPMST";
1157		- port->aux.dev = dev->dev;
1158		- created = true;
1159		- } else {
1160		- old_pdt = port->pdt;
1161		- old_ddps = port->ddps;
	2267	+ DRM_DEBUG_KMS("registering %s remote bus for %s\n",
	2268	+ port->aux.name, connector->kdev->kobj.name);
	2269	+
	2270	+ port->aux.dev = connector->kdev;
	2271	+ return drm_dp_aux_register_devnode(&port->aux);
	2272	+}
	2273	+EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
	2274	+
	2275	+/**
	2276	+ * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
	2277	+ * @connector: The MST connector
	2278	+ * @port: The MST port for this connector
	2279	+ *
	2280	+ * Helper to unregister the remote aux device for this MST port, registered by
	2281	+ * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
	2282	+ * connector's early_unregister hook.
	2283	+ */
	2284	+void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
	2285	+ struct drm_dp_mst_port *port)
	2286	+{
	2287	+ DRM_DEBUG_KMS("unregistering %s remote bus for %s\n",
	2288	+ port->aux.name, connector->kdev->kobj.name);
	2289	+ drm_dp_aux_unregister_devnode(&port->aux);
	2290	+}
	2291	+EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
	2292	+
	2293	+static void
	2294	+drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
	2295	+ struct drm_dp_mst_port *port)
	2296	+{
	2297	+ struct drm_dp_mst_topology_mgr *mgr = port->mgr;
	2298	+ char proppath[255];
	2299	+ int ret;
	2300	+
	2301	+ build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
	2302	+ port->connector = mgr->cbs->add_connector(mgr, port, proppath);
	2303	+ if (!port->connector) {
	2304	+ ret = -ENOMEM;
	2305	+ goto error;
1162	2306	}
1163	2307
1164		- port->pdt = port_msg->peer_device_type;
	2308	+ if (port->pdt != DP_PEER_DEVICE_NONE &&
	2309	+ drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
	2310	+ port->port_num >= DP_MST_LOGICAL_PORT_0) {
	2311	+ port->cached_edid = drm_get_edid(port->connector,
	2312	+ &port->aux.ddc);
	2313	+ drm_connector_set_tile_property(port->connector);
	2314	+ }
	2315	+
	2316	+ drm_connector_register(port->connector);
	2317	+ return;
	2318	+
	2319	+error:
	2320	+ DRM_ERROR("Failed to create connector for port %p: %d\n", port, ret);
	2321	+}
	2322	+
	2323	+/*
	2324	+ * Drop a topology reference, and unlink the port from the in-memory topology
	2325	+ * layout
	2326	+ */
	2327	+static void
	2328	+drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
	2329	+ struct drm_dp_mst_port *port)
	2330	+{
	2331	+ mutex_lock(&mgr->lock);
	2332	+ port->parent->num_ports--;
	2333	+ list_del(&port->next);
	2334	+ mutex_unlock(&mgr->lock);
	2335	+ drm_dp_mst_topology_put_port(port);
	2336	+}
	2337	+
	2338	+static struct drm_dp_mst_port *
	2339	+drm_dp_mst_add_port(struct drm_device *dev,
	2340	+ struct drm_dp_mst_topology_mgr *mgr,
	2341	+ struct drm_dp_mst_branch *mstb, u8 port_number)
	2342	+{
	2343	+ struct drm_dp_mst_port port = kzalloc(sizeof(port), GFP_KERNEL);
	2344	+
	2345	+ if (!port)
	2346	+ return NULL;
	2347	+
	2348	+ kref_init(&port->topology_kref);
	2349	+ kref_init(&port->malloc_kref);
	2350	+ port->parent = mstb;
	2351	+ port->port_num = port_number;
	2352	+ port->mgr = mgr;
	2353	+ port->aux.name = "DPMST";
	2354	+ port->aux.dev = dev->dev;
	2355	+ port->aux.is_remote = true;
	2356	+
	2357	+ /* initialize the MST downstream port's AUX crc work queue */
	2358	+ drm_dp_remote_aux_init(&port->aux);
	2359	+
	2360	+ /*
	2361	+ * Make sure the memory allocation for our parent branch stays
	2362	+ * around until our own memory allocation is released
	2363	+ */
	2364	+ drm_dp_mst_get_mstb_malloc(mstb);
	2365	+
	2366	+ return port;
	2367	+}
	2368	+
	2369	+static int
	2370	+drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
	2371	+ struct drm_device *dev,
	2372	+ struct drm_dp_link_addr_reply_port *port_msg)
	2373	+{
	2374	+ struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
	2375	+ struct drm_dp_mst_port *port;
	2376	+ int old_ddps = 0, ret;
	2377	+ u8 new_pdt = DP_PEER_DEVICE_NONE;
	2378	+ bool new_mcs = 0;
	2379	+ bool created = false, send_link_addr = false, changed = false;
	2380	+
	2381	+ port = drm_dp_get_port(mstb, port_msg->port_number);
	2382	+ if (!port) {
	2383	+ port = drm_dp_mst_add_port(dev, mgr, mstb,
	2384	+ port_msg->port_number);
	2385	+ if (!port)
	2386	+ return -ENOMEM;
	2387	+ created = true;
	2388	+ changed = true;
	2389	+ } else if (!port->input && port_msg->input_port && port->connector) {
	2390	+ /* Since port->connector can't be changed here, we create a
	2391	+ * new port if input_port changes from 0 to 1
	2392	+ */
	2393	+ drm_dp_mst_topology_unlink_port(mgr, port);
	2394	+ drm_dp_mst_topology_put_port(port);
	2395	+ port = drm_dp_mst_add_port(dev, mgr, mstb,
	2396	+ port_msg->port_number);
	2397	+ if (!port)
	2398	+ return -ENOMEM;
	2399	+ changed = true;
	2400	+ created = true;
	2401	+ } else if (port->input && !port_msg->input_port) {
	2402	+ changed = true;
	2403	+ } else if (port->connector) {
	2404	+ /* We're updating a port that's exposed to userspace, so do it
	2405	+ * under lock
	2406	+ */
	2407	+ drm_modeset_lock(&mgr->base.lock, NULL);
	2408	+
	2409	+ old_ddps = port->ddps;
	2410	+ changed = port->ddps != port_msg->ddps \|\|
	2411	+ (port->ddps &&
	2412	+ (port->ldps != port_msg->legacy_device_plug_status \|\|
	2413	+ port->dpcd_rev != port_msg->dpcd_revision \|\|
	2414	+ port->mcs != port_msg->mcs \|\|
	2415	+ port->pdt != port_msg->peer_device_type \|\|
	2416	+ port->num_sdp_stream_sinks !=
	2417	+ port_msg->num_sdp_stream_sinks));
	2418	+ }
	2419	+
1165	2420	port->input = port_msg->input_port;
1166		- port->mcs = port_msg->mcs;
	2421	+ if (!port->input)
	2422	+ new_pdt = port_msg->peer_device_type;
	2423	+ new_mcs = port_msg->mcs;
1167	2424	port->ddps = port_msg->ddps;
1168	2425	port->ldps = port_msg->legacy_device_plug_status;
1169	2426	port->dpcd_rev = port_msg->dpcd_revision;
..	..	@@ -1173,93 +2430,141 @@
1173	2430	/* manage mstb port lists with mgr lock - take a reference
1174	2431	for this list */
1175	2432	if (created) {
1176		- mutex_lock(&mstb->mgr->lock);
1177		- kref_get(&port->kref);
	2433	+ mutex_lock(&mgr->lock);
	2434	+ drm_dp_mst_topology_get_port(port);
1178	2435	list_add(&port->next, &mstb->ports);
1179		- mutex_unlock(&mstb->mgr->lock);
	2436	+ mstb->num_ports++;
	2437	+ mutex_unlock(&mgr->lock);
1180	2438	}
1181	2439
1182		- if (old_ddps != port->ddps) {
1183		- if (port->ddps) {
1184		- if (!port->input)
1185		- drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
	2440	+ /*
	2441	+ * Reprobe PBN caps on both hotplug, and when re-probing the link
	2442	+ * for our parent mstb
	2443	+ */
	2444	+ if (old_ddps != port->ddps \|\| !created) {
	2445	+ if (port->ddps && !port->input) {
	2446	+ ret = drm_dp_send_enum_path_resources(mgr, mstb,
	2447	+ port);
	2448	+ if (ret == 1)
	2449	+ changed = true;
1186	2450	} else {
1187		- port->available_pbn = 0;
1188		- }
1189		- }
1190		-
1191		- if (old_pdt != port->pdt && !port->input) {
1192		- drm_dp_port_teardown_pdt(port, old_pdt);
1193		-
1194		- ret = drm_dp_port_setup_pdt(port);
1195		- if (ret == true)
1196		- drm_dp_send_link_address(mstb->mgr, port->mstb);
1197		- }
1198		-
1199		- if (created && !port->input) {
1200		- char proppath[255];
1201		-
1202		- build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
1203		- port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
1204		- if (!port->connector) {
1205		- /* remove it from the port list */
1206		- mutex_lock(&mstb->mgr->lock);
1207		- list_del(&port->next);
1208		- mutex_unlock(&mstb->mgr->lock);
1209		- /* drop port list reference */
1210		- drm_dp_put_port(port);
1211		- goto out;
	2451	+ port->full_pbn = 0;
1212	2452	}
1213		- if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV \|\|
1214		- port->pdt == DP_PEER_DEVICE_SST_SINK) &&
1215		- port->port_num >= DP_MST_LOGICAL_PORT_0) {
1216		- port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
1217		- drm_connector_set_tile_property(port->connector);
1218		- }
1219		- (*mstb->mgr->cbs->register_connector)(port->connector);
1220	2453	}
1221	2454
1222		-out:
	2455	+ ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
	2456	+ if (ret == 1) {
	2457	+ send_link_addr = true;
	2458	+ } else if (ret < 0) {
	2459	+ DRM_ERROR("Failed to change PDT on port %p: %d\n",
	2460	+ port, ret);
	2461	+ goto fail;
	2462	+ }
	2463	+
	2464	+ /*
	2465	+ * If this port wasn't just created, then we're reprobing because
	2466	+ * we're coming out of suspend. In this case, always resend the link
	2467	+ * address if there's an MSTB on this port
	2468	+ */
	2469	+ if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
	2470	+ port->mcs)
	2471	+ send_link_addr = true;
	2472	+
	2473	+ if (port->connector)
	2474	+ drm_modeset_unlock(&mgr->base.lock);
	2475	+ else if (!port->input)
	2476	+ drm_dp_mst_port_add_connector(mstb, port);
	2477	+
	2478	+ if (send_link_addr && port->mstb) {
	2479	+ ret = drm_dp_send_link_address(mgr, port->mstb);
	2480	+ if (ret == 1) /* MSTB below us changed */
	2481	+ changed = true;
	2482	+ else if (ret < 0)
	2483	+ goto fail_put;
	2484	+ }
	2485	+
1223	2486	/* put reference to this port */
1224		- drm_dp_put_port(port);
	2487	+ drm_dp_mst_topology_put_port(port);
	2488	+ return changed;
	2489	+
	2490	+fail:
	2491	+ drm_dp_mst_topology_unlink_port(mgr, port);
	2492	+ if (port->connector)
	2493	+ drm_modeset_unlock(&mgr->base.lock);
	2494	+fail_put:
	2495	+ drm_dp_mst_topology_put_port(port);
	2496	+ return ret;
1225	2497	}
1226	2498
1227		-static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1228		- struct drm_dp_connection_status_notify *conn_stat)
	2499	+static void
	2500	+drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
	2501	+ struct drm_dp_connection_status_notify *conn_stat)
1229	2502	{
	2503	+ struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1230	2504	struct drm_dp_mst_port *port;
1231		- int old_pdt;
1232		- int old_ddps;
1233		- bool dowork = false;
	2505	+ int old_ddps, ret;
	2506	+ u8 new_pdt;
	2507	+ bool new_mcs;
	2508	+ bool dowork = false, create_connector = false;
	2509	+
1234	2510	port = drm_dp_get_port(mstb, conn_stat->port_number);
1235	2511	if (!port)
1236	2512	return;
1237	2513
	2514	+ if (port->connector) {
	2515	+ if (!port->input && conn_stat->input_port) {
	2516	+ /*
	2517	+ * We can't remove a connector from an already exposed
	2518	+ * port, so just throw the port out and make sure we
	2519	+ * reprobe the link address of it's parent MSTB
	2520	+ */
	2521	+ drm_dp_mst_topology_unlink_port(mgr, port);
	2522	+ mstb->link_address_sent = false;
	2523	+ dowork = true;
	2524	+ goto out;
	2525	+ }
	2526	+
	2527	+ /* Locking is only needed if the port's exposed to userspace */
	2528	+ drm_modeset_lock(&mgr->base.lock, NULL);
	2529	+ } else if (port->input && !conn_stat->input_port) {
	2530	+ create_connector = true;
	2531	+ /* Reprobe link address so we get num_sdp_streams */
	2532	+ mstb->link_address_sent = false;
	2533	+ dowork = true;
	2534	+ }
	2535	+
1238	2536	old_ddps = port->ddps;
1239		- old_pdt = port->pdt;
1240		- port->pdt = conn_stat->peer_device_type;
1241		- port->mcs = conn_stat->message_capability_status;
	2537	+ port->input = conn_stat->input_port;
1242	2538	port->ldps = conn_stat->legacy_device_plug_status;
1243	2539	port->ddps = conn_stat->displayport_device_plug_status;
1244	2540
1245	2541	if (old_ddps != port->ddps) {
1246		- if (port->ddps) {
1247		- dowork = true;
1248		- } else {
1249		- port->available_pbn = 0;
1250		- }
1251		- }
1252		- if (old_pdt != port->pdt && !port->input) {
1253		- drm_dp_port_teardown_pdt(port, old_pdt);
1254		-
1255		- if (drm_dp_port_setup_pdt(port))
1256		- dowork = true;
	2542	+ if (port->ddps && !port->input)
	2543	+ drm_dp_send_enum_path_resources(mgr, mstb, port);
	2544	+ else
	2545	+ port->full_pbn = 0;
1257	2546	}
1258	2547
1259		- drm_dp_put_port(port);
	2548	+ new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
	2549	+ new_mcs = conn_stat->message_capability_status;
	2550	+ ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
	2551	+ if (ret == 1) {
	2552	+ dowork = true;
	2553	+ } else if (ret < 0) {
	2554	+ DRM_ERROR("Failed to change PDT for port %p: %d\n",
	2555	+ port, ret);
	2556	+ dowork = false;
	2557	+ }
	2558	+
	2559	+ if (port->connector)
	2560	+ drm_modeset_unlock(&mgr->base.lock);
	2561	+ else if (create_connector)
	2562	+ drm_dp_mst_port_add_connector(mstb, port);
	2563	+
	2564	+out:
	2565	+ drm_dp_mst_topology_put_port(port);
1260	2566	if (dowork)
1261	2567	queue_work(system_long_wq, &mstb->mgr->work);
1262		-
1263	2568	}
1264	2569
1265	2570	static struct drm_dp_mst_branch drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr mgr,
..	..	@@ -1267,7 +2572,7 @@
1267	2572	{
1268	2573	struct drm_dp_mst_branch *mstb;
1269	2574	struct drm_dp_mst_port *port;
1270		- int i;
	2575	+ int i, ret;
1271	2576	/* find the port by iterating down */
1272	2577
1273	2578	mutex_lock(&mgr->lock);
..	..	@@ -1292,7 +2597,9 @@
1292	2597	}
1293	2598	}
1294	2599	}
1295		- kref_get(&mstb->kref);
	2600	+ ret = drm_dp_mst_topology_try_get_mstb(mstb);
	2601	+ if (!ret)
	2602	+ mstb = NULL;
1296	2603	out:
1297	2604	mutex_unlock(&mgr->lock);
1298	2605	return mstb;
..	..	@@ -1300,7 +2607,7 @@
1300	2607
1301	2608	static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
1302	2609	struct drm_dp_mst_branch *mstb,
1303		- uint8_t *guid)
	2610	+ const uint8_t *guid)
1304	2611	{
1305	2612	struct drm_dp_mst_branch *found_mstb;
1306	2613	struct drm_dp_mst_port *port;
..	..	@@ -1322,67 +2629,112 @@
1322	2629	return NULL;
1323	2630	}
1324	2631
1325		-static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid(
1326		- struct drm_dp_mst_topology_mgr *mgr,
1327		- uint8_t *guid)
	2632	+static struct drm_dp_mst_branch *
	2633	+drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
	2634	+ const uint8_t *guid)
1328	2635	{
1329	2636	struct drm_dp_mst_branch *mstb;
	2637	+ int ret;
1330	2638
1331	2639	/* find the port by iterating down */
1332	2640	mutex_lock(&mgr->lock);
1333	2641
1334	2642	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
1335		-
1336		- if (mstb)
1337		- kref_get(&mstb->kref);
	2643	+ if (mstb) {
	2644	+ ret = drm_dp_mst_topology_try_get_mstb(mstb);
	2645	+ if (!ret)
	2646	+ mstb = NULL;
	2647	+ }
1338	2648
1339	2649	mutex_unlock(&mgr->lock);
1340	2650	return mstb;
1341	2651	}
1342	2652
1343		-static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
	2653	+static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1344	2654	struct drm_dp_mst_branch *mstb)
1345	2655	{
1346	2656	struct drm_dp_mst_port *port;
1347		- struct drm_dp_mst_branch *mstb_child;
1348		- if (!mstb->link_address_sent)
1349		- drm_dp_send_link_address(mgr, mstb);
	2657	+ int ret;
	2658	+ bool changed = false;
	2659	+
	2660	+ if (!mstb->link_address_sent) {
	2661	+ ret = drm_dp_send_link_address(mgr, mstb);
	2662	+ if (ret == 1)
	2663	+ changed = true;
	2664	+ else if (ret < 0)
	2665	+ return ret;
	2666	+ }
1350	2667
1351	2668	list_for_each_entry(port, &mstb->ports, next) {
1352		- if (port->input)
	2669	+ struct drm_dp_mst_branch *mstb_child = NULL;
	2670	+
	2671	+ if (port->input \|\| !port->ddps)
1353	2672	continue;
1354	2673
1355		- if (!port->ddps)
1356		- continue;
	2674	+ if (port->mstb)
	2675	+ mstb_child = drm_dp_mst_topology_get_mstb_validated(
	2676	+ mgr, port->mstb);
1357	2677
1358		- if (!port->available_pbn)
1359		- drm_dp_send_enum_path_resources(mgr, mstb, port);
1360		-
1361		- if (port->mstb) {
1362		- mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
1363		- if (mstb_child) {
1364		- drm_dp_check_and_send_link_address(mgr, mstb_child);
1365		- drm_dp_put_mst_branch_device(mstb_child);
1366		- }
	2678	+ if (mstb_child) {
	2679	+ ret = drm_dp_check_and_send_link_address(mgr,
	2680	+ mstb_child);
	2681	+ drm_dp_mst_topology_put_mstb(mstb_child);
	2682	+ if (ret == 1)
	2683	+ changed = true;
	2684	+ else if (ret < 0)
	2685	+ return ret;
1367	2686	}
1368	2687	}
	2688	+
	2689	+ return changed;
1369	2690	}
1370	2691
1371	2692	static void drm_dp_mst_link_probe_work(struct work_struct *work)
1372	2693	{
1373		- struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
	2694	+ struct drm_dp_mst_topology_mgr *mgr =
	2695	+ container_of(work, struct drm_dp_mst_topology_mgr, work);
	2696	+ struct drm_device *dev = mgr->dev;
1374	2697	struct drm_dp_mst_branch *mstb;
	2698	+ int ret;
	2699	+ bool clear_payload_id_table;
	2700	+
	2701	+ mutex_lock(&mgr->probe_lock);
1375	2702
1376	2703	mutex_lock(&mgr->lock);
	2704	+ clear_payload_id_table = !mgr->payload_id_table_cleared;
	2705	+ mgr->payload_id_table_cleared = true;
	2706	+
1377	2707	mstb = mgr->mst_primary;
1378	2708	if (mstb) {
1379		- kref_get(&mstb->kref);
	2709	+ ret = drm_dp_mst_topology_try_get_mstb(mstb);
	2710	+ if (!ret)
	2711	+ mstb = NULL;
1380	2712	}
1381	2713	mutex_unlock(&mgr->lock);
1382		- if (mstb) {
1383		- drm_dp_check_and_send_link_address(mgr, mstb);
1384		- drm_dp_put_mst_branch_device(mstb);
	2714	+ if (!mstb) {
	2715	+ mutex_unlock(&mgr->probe_lock);
	2716	+ return;
1385	2717	}
	2718	+
	2719	+ /*
	2720	+ * Certain branch devices seem to incorrectly report an available_pbn
	2721	+ * of 0 on downstream sinks, even after clearing the
	2722	+ * DP_PAYLOAD_ALLOCATE_* registers in
	2723	+ * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
	2724	+ * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
	2725	+ * things work again.
	2726	+ */
	2727	+ if (clear_payload_id_table) {
	2728	+ DRM_DEBUG_KMS("Clearing payload ID table\n");
	2729	+ drm_dp_send_clear_payload_id_table(mgr, mstb);
	2730	+ }
	2731	+
	2732	+ ret = drm_dp_check_and_send_link_address(mgr, mstb);
	2733	+ drm_dp_mst_topology_put_mstb(mstb);
	2734	+
	2735	+ mutex_unlock(&mgr->probe_lock);
	2736	+ if (ret)
	2737	+ drm_kms_helper_hotplug_event(dev);
1386	2738	}
1387	2739
1388	2740	static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
..	..	@@ -1401,7 +2753,8 @@
1401	2753	return false;
1402	2754	}
1403	2755
1404		-static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
	2756	+static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
	2757	+ u8 port_num, u32 offset, u8 num_bytes)
1405	2758	{
1406	2759	struct drm_dp_sideband_msg_req_body req;
1407	2760
..	..	@@ -1410,8 +2763,6 @@
1410	2763	req.u.dpcd_read.dpcd_address = offset;
1411	2764	req.u.dpcd_read.num_bytes = num_bytes;
1412	2765	drm_dp_encode_sideband_req(&req, msg);
1413		-
1414		- return 0;
1415	2766	}
1416	2767
1417	2768	static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
..	..	@@ -1452,34 +2803,24 @@
1452	2803	struct drm_dp_mst_branch *mstb = txmsg->dst;
1453	2804	u8 req_type;
1454	2805
1455		- /* both msg slots are full */
1456		- if (txmsg->seqno == -1) {
1457		- if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1458		- DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1459		- return -EAGAIN;
1460		- }
1461		- if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1462		- txmsg->seqno = mstb->last_seqno;
1463		- mstb->last_seqno ^= 1;
1464		- } else if (mstb->tx_slots[0] == NULL)
1465		- txmsg->seqno = 0;
1466		- else
1467		- txmsg->seqno = 1;
1468		- mstb->tx_slots[txmsg->seqno] = txmsg;
1469		- }
1470		-
1471	2806	req_type = txmsg->msg[0] & 0x7f;
1472	2807	if (req_type == DP_CONNECTION_STATUS_NOTIFY \|\|
1473		- req_type == DP_RESOURCE_STATUS_NOTIFY)
	2808	+ req_type == DP_RESOURCE_STATUS_NOTIFY \|\|
	2809	+ req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
1474	2810	hdr->broadcast = 1;
1475	2811	else
1476	2812	hdr->broadcast = 0;
1477	2813	hdr->path_msg = txmsg->path_msg;
1478		- hdr->lct = mstb->lct;
1479		- hdr->lcr = mstb->lct - 1;
1480		- if (mstb->lct > 1)
1481		- memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1482		- hdr->seqno = txmsg->seqno;
	2814	+ if (hdr->broadcast) {
	2815	+ hdr->lct = 1;
	2816	+ hdr->lcr = 6;
	2817	+ } else {
	2818	+ hdr->lct = mstb->lct;
	2819	+ hdr->lcr = mstb->lct - 1;
	2820	+ }
	2821	+
	2822	+ memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
	2823	+
1483	2824	return 0;
1484	2825	}
1485	2826	/*
..	..	@@ -1494,15 +2835,15 @@
1494	2835	int len, space, idx, tosend;
1495	2836	int ret;
1496	2837
	2838	+ if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
	2839	+ return 0;
	2840	+
1497	2841	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
1498	2842
1499		- if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
1500		- txmsg->seqno = -1;
	2843	+ if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
1501	2844	txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
1502		- }
1503	2845
1504		- /* make hdr from dst mst - for replies use seqno
1505		- otherwise assign one */
	2846	+ /* make hdr from dst mst */
1506	2847	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
1507	2848	if (ret < 0)
1508	2849	return ret;
..	..	@@ -1529,7 +2870,12 @@
1529	2870
1530	2871	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
1531	2872	if (ret) {
1532		- DRM_DEBUG_KMS("sideband msg failed to send\n");
	2873	+ if (drm_debug_enabled(DRM_UT_DP)) {
	2874	+ struct drm_printer p = drm_debug_printer(DBG_PREFIX);
	2875	+
	2876	+ drm_printf(&p, "sideband msg failed to send\n");
	2877	+ drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
	2878	+ }
1533	2879	return ret;
1534	2880	}
1535	2881
..	..	@@ -1552,37 +2898,14 @@
1552	2898	if (list_empty(&mgr->tx_msg_downq))
1553	2899	return;
1554	2900
1555		- txmsg = list_first_entry(&mgr->tx_msg_downq, struct drm_dp_sideband_msg_tx, next);
	2901	+ txmsg = list_first_entry(&mgr->tx_msg_downq,
	2902	+ struct drm_dp_sideband_msg_tx, next);
1556	2903	ret = process_single_tx_qlock(mgr, txmsg, false);
1557		- if (ret == 1) {
1558		- /* txmsg is sent it should be in the slots now */
1559		- list_del(&txmsg->next);
1560		- } else if (ret) {
	2904	+ if (ret < 0) {
1561	2905	DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1562	2906	list_del(&txmsg->next);
1563		- if (txmsg->seqno != -1)
1564		- txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1565	2907	txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1566	2908	wake_up_all(&mgr->tx_waitq);
1567		- }
1568		-}
1569		-
1570		-/* called holding qlock */
1571		-static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1572		- struct drm_dp_sideband_msg_tx *txmsg)
1573		-{
1574		- int ret;
1575		-
1576		- /* construct a chunk from the first msg in the tx_msg queue */
1577		- ret = process_single_tx_qlock(mgr, txmsg, true);
1578		-
1579		- if (ret != 1)
1580		- DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1581		-
1582		- if (txmsg->seqno != -1) {
1583		- WARN_ON((unsigned int)txmsg->seqno >
1584		- ARRAY_SIZE(txmsg->dst->tx_slots));
1585		- txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1586	2909	}
1587	2910	}
1588	2911
..	..	@@ -1591,15 +2914,124 @@
1591	2914	{
1592	2915	mutex_lock(&mgr->qlock);
1593	2916	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
	2917	+
	2918	+ if (drm_debug_enabled(DRM_UT_DP)) {
	2919	+ struct drm_printer p = drm_debug_printer(DBG_PREFIX);
	2920	+
	2921	+ drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
	2922	+ }
	2923	+
1594	2924	if (list_is_singular(&mgr->tx_msg_downq))
1595	2925	process_single_down_tx_qlock(mgr);
1596	2926	mutex_unlock(&mgr->qlock);
1597	2927	}
1598	2928
1599		-static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
	2929	+static void
	2930	+drm_dp_dump_link_address(struct drm_dp_link_address_ack_reply *reply)
	2931	+{
	2932	+ struct drm_dp_link_addr_reply_port *port_reply;
	2933	+ int i;
	2934	+
	2935	+ for (i = 0; i < reply->nports; i++) {
	2936	+ port_reply = &reply->ports[i];
	2937	+ DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
	2938	+ i,
	2939	+ port_reply->input_port,
	2940	+ port_reply->peer_device_type,
	2941	+ port_reply->port_number,
	2942	+ port_reply->dpcd_revision,
	2943	+ port_reply->mcs,
	2944	+ port_reply->ddps,
	2945	+ port_reply->legacy_device_plug_status,
	2946	+ port_reply->num_sdp_streams,
	2947	+ port_reply->num_sdp_stream_sinks);
	2948	+ }
	2949	+}
	2950	+
	2951	+static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1600	2952	struct drm_dp_mst_branch *mstb)
1601	2953	{
1602		- int len;
	2954	+ struct drm_dp_sideband_msg_tx *txmsg;
	2955	+ struct drm_dp_link_address_ack_reply *reply;
	2956	+ struct drm_dp_mst_port port, tmp;
	2957	+ int i, ret, port_mask = 0;
	2958	+ bool changed = false;
	2959	+
	2960	+ txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
	2961	+ if (!txmsg)
	2962	+ return -ENOMEM;
	2963	+
	2964	+ txmsg->dst = mstb;
	2965	+ build_link_address(txmsg);
	2966	+
	2967	+ mstb->link_address_sent = true;
	2968	+ drm_dp_queue_down_tx(mgr, txmsg);
	2969	+
	2970	+ /* FIXME: Actually do some real error handling here */
	2971	+ ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
	2972	+ if (ret <= 0) {
	2973	+ DRM_ERROR("Sending link address failed with %d\n", ret);
	2974	+ goto out;
	2975	+ }
	2976	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
	2977	+ DRM_ERROR("link address NAK received\n");
	2978	+ ret = -EIO;
	2979	+ goto out;
	2980	+ }
	2981	+
	2982	+ reply = &txmsg->reply.u.link_addr;
	2983	+ DRM_DEBUG_KMS("link address reply: %d\n", reply->nports);
	2984	+ drm_dp_dump_link_address(reply);
	2985	+
	2986	+ ret = drm_dp_check_mstb_guid(mstb, reply->guid);
	2987	+ if (ret) {
	2988	+ char buf[64];
	2989	+
	2990	+ drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
	2991	+ DRM_ERROR("GUID check on %s failed: %d\n",
	2992	+ buf, ret);
	2993	+ goto out;
	2994	+ }
	2995	+
	2996	+ for (i = 0; i < reply->nports; i++) {
	2997	+ port_mask \|= BIT(reply->ports[i].port_number);
	2998	+ ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
	2999	+ &reply->ports[i]);
	3000	+ if (ret == 1)
	3001	+ changed = true;
	3002	+ else if (ret < 0)
	3003	+ goto out;
	3004	+ }
	3005	+
	3006	+ /* Prune any ports that are currently a part of mstb in our in-memory
	3007	+ * topology, but were not seen in this link address. Usually this
	3008	+ * means that they were removed while the topology was out of sync,
	3009	+ * e.g. during suspend/resume
	3010	+ */
	3011	+ mutex_lock(&mgr->lock);
	3012	+ list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
	3013	+ if (port_mask & BIT(port->port_num))
	3014	+ continue;
	3015	+
	3016	+ DRM_DEBUG_KMS("port %d was not in link address, removing\n",
	3017	+ port->port_num);
	3018	+ list_del(&port->next);
	3019	+ drm_dp_mst_topology_put_port(port);
	3020	+ changed = true;
	3021	+ }
	3022	+ mutex_unlock(&mgr->lock);
	3023	+
	3024	+out:
	3025	+ if (ret <= 0)
	3026	+ mstb->link_address_sent = false;
	3027	+ kfree(txmsg);
	3028	+ return ret < 0 ? ret : changed;
	3029	+}
	3030	+
	3031	+static void
	3032	+drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
	3033	+ struct drm_dp_mst_branch *mstb)
	3034	+{
1603	3035	struct drm_dp_sideband_msg_tx *txmsg;
1604	3036	int ret;
1605	3037
..	..	@@ -1608,52 +3040,23 @@
1608	3040	return;
1609	3041
1610	3042	txmsg->dst = mstb;
1611		- len = build_link_address(txmsg);
	3043	+ build_clear_payload_id_table(txmsg);
1612	3044
1613		- mstb->link_address_sent = true;
1614	3045	drm_dp_queue_down_tx(mgr, txmsg);
1615	3046
1616	3047	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1617		- if (ret > 0) {
1618		- int i;
1619		-
1620		- if (txmsg->reply.reply_type == 1)
1621		- DRM_DEBUG_KMS("link address nak received\n");
1622		- else {
1623		- DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
1624		- for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1625		- DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n", i,
1626		- txmsg->reply.u.link_addr.ports[i].input_port,
1627		- txmsg->reply.u.link_addr.ports[i].peer_device_type,
1628		- txmsg->reply.u.link_addr.ports[i].port_number,
1629		- txmsg->reply.u.link_addr.ports[i].dpcd_revision,
1630		- txmsg->reply.u.link_addr.ports[i].mcs,
1631		- txmsg->reply.u.link_addr.ports[i].ddps,
1632		- txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
1633		- txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
1634		- txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
1635		- }
1636		-
1637		- drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid);
1638		-
1639		- for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1640		- drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
1641		- }
1642		- (*mgr->cbs->hotplug)(mgr);
1643		- }
1644		- } else {
1645		- mstb->link_address_sent = false;
1646		- DRM_DEBUG_KMS("link address failed %d\n", ret);
1647		- }
	3048	+ if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
	3049	+ DRM_DEBUG_KMS("clear payload table id nak received\n");
1648	3050
1649	3051	kfree(txmsg);
1650	3052	}
1651	3053
1652		-static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
1653		- struct drm_dp_mst_branch *mstb,
1654		- struct drm_dp_mst_port *port)
	3054	+static int
	3055	+drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
	3056	+ struct drm_dp_mst_branch *mstb,
	3057	+ struct drm_dp_mst_port *port)
1655	3058	{
1656		- int len;
	3059	+ struct drm_dp_enum_path_resources_ack_reply *path_res;
1657	3060	struct drm_dp_sideband_msg_tx *txmsg;
1658	3061	int ret;
1659	3062
..	..	@@ -1662,26 +3065,41 @@
1662	3065	return -ENOMEM;
1663	3066
1664	3067	txmsg->dst = mstb;
1665		- len = build_enum_path_resources(txmsg, port->port_num);
	3068	+ build_enum_path_resources(txmsg, port->port_num);
1666	3069
1667	3070	drm_dp_queue_down_tx(mgr, txmsg);
1668	3071
1669	3072	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1670	3073	if (ret > 0) {
1671		- if (txmsg->reply.reply_type == 1)
	3074	+ ret = 0;
	3075	+ path_res = &txmsg->reply.u.path_resources;
	3076	+
	3077	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
1672	3078	DRM_DEBUG_KMS("enum path resources nak received\n");
1673		- else {
1674		- if (port->port_num != txmsg->reply.u.path_resources.port_number)
	3079	+ } else {
	3080	+ if (port->port_num != path_res->port_number)
1675	3081	DRM_ERROR("got incorrect port in response\n");
1676		- DRM_DEBUG_KMS("enum path resources %d: %d %d\n", txmsg->reply.u.path_resources.port_number, txmsg->reply.u.path_resources.full_payload_bw_number,
1677		- txmsg->reply.u.path_resources.avail_payload_bw_number);
1678		- port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
1679		- port->fec_capable = txmsg->reply.u.path_resources.fec_capable;
	3082	+
	3083	+ DRM_DEBUG_KMS("enum path resources %d: %d %d\n",
	3084	+ path_res->port_number,
	3085	+ path_res->full_payload_bw_number,
	3086	+ path_res->avail_payload_bw_number);
	3087	+
	3088	+ /*
	3089	+ * If something changed, make sure we send a
	3090	+ * hotplug
	3091	+ */
	3092	+ if (port->full_pbn != path_res->full_payload_bw_number \|\|
	3093	+ port->fec_capable != path_res->fec_capable)
	3094	+ ret = 1;
	3095	+
	3096	+ port->full_pbn = path_res->full_payload_bw_number;
	3097	+ port->fec_capable = path_res->fec_capable;
1680	3098	}
1681	3099	}
1682	3100
1683	3101	kfree(txmsg);
1684		- return 0;
	3102	+ return ret;
1685	3103	}
1686	3104
1687	3105	static struct drm_dp_mst_port drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch mstb)
..	..	@@ -1695,22 +3113,40 @@
1695	3113	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
1696	3114	}
1697	3115
1698		-static struct drm_dp_mst_branch drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr mgr,
1699		- struct drm_dp_mst_branch *mstb,
1700		- int *port_num)
	3116	+/*
	3117	+ * Searches upwards in the topology starting from mstb to try to find the
	3118	+ * closest available parent of mstb that's still connected to the rest of the
	3119	+ * topology. This can be used in order to perform operations like releasing
	3120	+ * payloads, where the branch device which owned the payload may no longer be
	3121	+ * around and thus would require that the payload on the last living relative
	3122	+ * be freed instead.
	3123	+ */
	3124	+static struct drm_dp_mst_branch *
	3125	+drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
	3126	+ struct drm_dp_mst_branch *mstb,
	3127	+ int *port_num)
1701	3128	{
1702	3129	struct drm_dp_mst_branch *rmstb = NULL;
1703	3130	struct drm_dp_mst_port *found_port;
1704		- mutex_lock(&mgr->lock);
1705		- if (mgr->mst_primary) {
1706		- found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
1707	3131
1708		- if (found_port) {
	3132	+ mutex_lock(&mgr->lock);
	3133	+ if (!mgr->mst_primary)
	3134	+ goto out;
	3135	+
	3136	+ do {
	3137	+ found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
	3138	+ if (!found_port)
	3139	+ break;
	3140	+
	3141	+ if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
1709	3142	rmstb = found_port->parent;
1710		- kref_get(&rmstb->kref);
1711	3143	*port_num = found_port->port_num;
	3144	+ } else {
	3145	+ /* Search again, starting from this parent */
	3146	+ mstb = found_port->parent;
1712	3147	}
1713		- }
	3148	+ } while (!rmstb);
	3149	+out:
1714	3150	mutex_unlock(&mgr->lock);
1715	3151	return rmstb;
1716	3152	}
..	..	@@ -1722,23 +3158,19 @@
1722	3158	{
1723	3159	struct drm_dp_sideband_msg_tx *txmsg;
1724	3160	struct drm_dp_mst_branch *mstb;
1725		- int len, ret, port_num;
	3161	+ int ret, port_num;
1726	3162	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
1727	3163	int i;
1728	3164
1729		- port = drm_dp_get_validated_port_ref(mgr, port);
1730		- if (!port)
1731		- return -EINVAL;
1732		-
1733	3165	port_num = port->port_num;
1734		- mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
	3166	+ mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
1735	3167	if (!mstb) {
1736		- mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num);
	3168	+ mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
	3169	+ port->parent,
	3170	+ &port_num);
1737	3171
1738		- if (!mstb) {
1739		- drm_dp_put_port(port);
	3172	+ if (!mstb)
1740	3173	return -EINVAL;
1741		- }
1742	3174	}
1743	3175
1744	3176	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
..	..	@@ -1751,23 +3183,30 @@
1751	3183	sinks[i] = i;
1752	3184
1753	3185	txmsg->dst = mstb;
1754		- len = build_allocate_payload(txmsg, port_num,
1755		- id,
1756		- pbn, port->num_sdp_streams, sinks);
	3186	+ build_allocate_payload(txmsg, port_num,
	3187	+ id,
	3188	+ pbn, port->num_sdp_streams, sinks);
1757	3189
1758	3190	drm_dp_queue_down_tx(mgr, txmsg);
1759	3191
	3192	+ /*
	3193	+ * FIXME: there is a small chance that between getting the last
	3194	+ * connected mstb and sending the payload message, the last connected
	3195	+ * mstb could also be removed from the topology. In the future, this
	3196	+ * needs to be fixed by restarting the
	3197	+ * drm_dp_get_last_connected_port_and_mstb() search in the event of a
	3198	+ * timeout if the topology is still connected to the system.
	3199	+ */
1760	3200	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1761	3201	if (ret > 0) {
1762		- if (txmsg->reply.reply_type == 1) {
	3202	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
1763	3203	ret = -EINVAL;
1764		- } else
	3204	+ else
1765	3205	ret = 0;
1766	3206	}
1767	3207	kfree(txmsg);
1768	3208	fail_put:
1769		- drm_dp_put_mst_branch_device(mstb);
1770		- drm_dp_put_port(port);
	3209	+ drm_dp_mst_topology_put_mstb(mstb);
1771	3210	return ret;
1772	3211	}
1773	3212
..	..	@@ -1775,71 +3214,86 @@
1775	3214	struct drm_dp_mst_port *port, bool power_up)
1776	3215	{
1777	3216	struct drm_dp_sideband_msg_tx *txmsg;
1778		- int len, ret;
	3217	+ int ret;
1779	3218
1780		- port = drm_dp_get_validated_port_ref(mgr, port);
	3219	+ port = drm_dp_mst_topology_get_port_validated(mgr, port);
1781	3220	if (!port)
1782	3221	return -EINVAL;
1783	3222
1784	3223	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1785	3224	if (!txmsg) {
1786		- drm_dp_put_port(port);
	3225	+ drm_dp_mst_topology_put_port(port);
1787	3226	return -ENOMEM;
1788	3227	}
1789	3228
1790	3229	txmsg->dst = port->parent;
1791		- len = build_power_updown_phy(txmsg, port->port_num, power_up);
	3230	+ build_power_updown_phy(txmsg, port->port_num, power_up);
1792	3231	drm_dp_queue_down_tx(mgr, txmsg);
1793	3232
1794	3233	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
1795	3234	if (ret > 0) {
1796		- if (txmsg->reply.reply_type == 1)
	3235	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
1797	3236	ret = -EINVAL;
1798	3237	else
1799	3238	ret = 0;
1800	3239	}
1801	3240	kfree(txmsg);
1802		- drm_dp_put_port(port);
	3241	+ drm_dp_mst_topology_put_port(port);
1803	3242
1804	3243	return ret;
1805	3244	}
1806	3245	EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
1807	3246
1808		-int drm_dp_mst_get_dsc_info(struct drm_dp_mst_topology_mgr *mgr,
	3247	+int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
1809	3248	struct drm_dp_mst_port *port,
1810		- struct drm_dp_mst_dsc_info *dsc_info)
	3249	+ struct drm_dp_query_stream_enc_status_ack_reply *status)
1811	3250	{
1812		- if (!dsc_info)
1813		- return -EINVAL;
	3251	+ struct drm_dp_sideband_msg_tx *txmsg;
	3252	+ u8 nonce[7];
	3253	+ int len, ret;
1814	3254
1815		- port = drm_dp_get_validated_port_ref(mgr, port);
1816		- if (!port)
1817		- return -EINVAL;
	3255	+ txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
	3256	+ if (!txmsg)
	3257	+ return -ENOMEM;
1818	3258
1819		- memcpy(dsc_info, &port->dsc_info, sizeof(struct drm_dp_mst_dsc_info));
1820		- drm_dp_put_port(port);
	3259	+ port = drm_dp_mst_topology_get_port_validated(mgr, port);
	3260	+ if (!port) {
	3261	+ ret = -EINVAL;
	3262	+ goto out_get_port;
	3263	+ }
1821	3264
1822		- return 0;
	3265	+ get_random_bytes(nonce, sizeof(nonce));
	3266	+
	3267	+ /*
	3268	+ * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
	3269	+ * transaction at the MST Branch device directly connected to the
	3270	+ * Source"
	3271	+ */
	3272	+ txmsg->dst = mgr->mst_primary;
	3273	+
	3274	+ len = build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
	3275	+
	3276	+ drm_dp_queue_down_tx(mgr, txmsg);
	3277	+
	3278	+ ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
	3279	+ if (ret < 0) {
	3280	+ goto out;
	3281	+ } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
	3282	+ drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
	3283	+ ret = -ENXIO;
	3284	+ goto out;
	3285	+ }
	3286	+
	3287	+ ret = 0;
	3288	+ memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
	3289	+
	3290	+out:
	3291	+ drm_dp_mst_topology_put_port(port);
	3292	+out_get_port:
	3293	+ kfree(txmsg);
	3294	+ return ret;
1823	3295	}
1824		-EXPORT_SYMBOL_GPL(drm_dp_mst_get_dsc_info);
1825		-
1826		-int drm_dp_mst_update_dsc_info(struct drm_dp_mst_topology_mgr *mgr,
1827		- struct drm_dp_mst_port *port,
1828		- struct drm_dp_mst_dsc_info *dsc_info)
1829		-{
1830		- if (!dsc_info)
1831		- return -EINVAL;
1832		-
1833		- port = drm_dp_get_validated_port_ref(mgr, port);
1834		- if (!port)
1835		- return -EINVAL;
1836		-
1837		- memcpy(&port->dsc_info, dsc_info, sizeof(struct drm_dp_mst_dsc_info));
1838		- drm_dp_put_port(port);
1839		-
1840		- return 0;
1841		-}
1842		-EXPORT_SYMBOL_GPL(drm_dp_mst_update_dsc_info);
	3296	+EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
1843	3297
1844	3298	static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1845	3299	int id,
..	..	@@ -1862,6 +3316,7 @@
1862	3316	struct drm_dp_payload *payload)
1863	3317	{
1864	3318	int ret;
	3319	+
1865	3320	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
1866	3321	if (ret < 0)
1867	3322	return ret;
..	..	@@ -1875,7 +3330,7 @@
1875	3330	struct drm_dp_payload *payload)
1876	3331	{
1877	3332	DRM_DEBUG_KMS("\n");
1878		- /* its okay for these to fail */
	3333	+ /* it's okay for these to fail */
1879	3334	if (port) {
1880	3335	drm_dp_payload_send_msg(mgr, port, id, 0);
1881	3336	}
..	..	@@ -1908,72 +3363,114 @@
1908	3363	*/
1909	3364	int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
1910	3365	{
1911		- int i, j;
1912		- int cur_slots = 1;
1913	3366	struct drm_dp_payload req_payload;
1914	3367	struct drm_dp_mst_port *port;
	3368	+ int i, j;
	3369	+ int cur_slots = 1;
	3370	+ bool skip;
1915	3371
1916	3372	mutex_lock(&mgr->payload_lock);
1917	3373	for (i = 0; i < mgr->max_payloads; i++) {
	3374	+ struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
	3375	+ struct drm_dp_payload *payload = &mgr->payloads[i];
	3376	+ bool put_port = false;
	3377	+
1918	3378	/* solve the current payloads - compare to the hw ones
1919	3379	- update the hw view */
1920	3380	req_payload.start_slot = cur_slots;
1921		- if (mgr->proposed_vcpis[i]) {
1922		- port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1923		- port = drm_dp_get_validated_port_ref(mgr, port);
1924		- if (!port) {
1925		- mutex_unlock(&mgr->payload_lock);
1926		- return -EINVAL;
	3381	+ if (vcpi) {
	3382	+ port = container_of(vcpi, struct drm_dp_mst_port,
	3383	+ vcpi);
	3384	+
	3385	+ mutex_lock(&mgr->lock);
	3386	+ skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
	3387	+ mutex_unlock(&mgr->lock);
	3388	+
	3389	+ if (skip) {
	3390	+ drm_dbg_kms(mgr->dev,
	3391	+ "Virtual channel %d is not in current topology\n",
	3392	+ i);
	3393	+ continue;
1927	3394	}
1928		- req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
1929		- req_payload.vcpi = mgr->proposed_vcpis[i]->vcpi;
	3395	+ /* Validated ports don't matter if we're releasing
	3396	+ * VCPI
	3397	+ */
	3398	+ if (vcpi->num_slots) {
	3399	+ port = drm_dp_mst_topology_get_port_validated(
	3400	+ mgr, port);
	3401	+ if (!port) {
	3402	+ if (vcpi->num_slots == payload->num_slots) {
	3403	+ cur_slots += vcpi->num_slots;
	3404	+ payload->start_slot = req_payload.start_slot;
	3405	+ continue;
	3406	+ } else {
	3407	+ drm_dbg_kms(mgr->dev,
	3408	+ "Fail:set payload to invalid sink");
	3409	+ mutex_unlock(&mgr->payload_lock);
	3410	+ return -EINVAL;
	3411	+ }
	3412	+ }
	3413	+ put_port = true;
	3414	+ }
	3415	+
	3416	+ req_payload.num_slots = vcpi->num_slots;
	3417	+ req_payload.vcpi = vcpi->vcpi;
1930	3418	} else {
1931	3419	port = NULL;
1932	3420	req_payload.num_slots = 0;
1933	3421	}
1934	3422
1935		- if (mgr->payloads[i].start_slot != req_payload.start_slot) {
1936		- mgr->payloads[i].start_slot = req_payload.start_slot;
1937		- }
	3423	+ payload->start_slot = req_payload.start_slot;
1938	3424	/* work out what is required to happen with this payload */
1939		- if (mgr->payloads[i].num_slots != req_payload.num_slots) {
	3425	+ if (payload->num_slots != req_payload.num_slots) {
1940	3426
1941	3427	/* need to push an update for this payload */
1942	3428	if (req_payload.num_slots) {
1943		- drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
1944		- mgr->payloads[i].num_slots = req_payload.num_slots;
1945		- mgr->payloads[i].vcpi = req_payload.vcpi;
1946		- } else if (mgr->payloads[i].num_slots) {
1947		- mgr->payloads[i].num_slots = 0;
1948		- drm_dp_destroy_payload_step1(mgr, port, mgr->payloads[i].vcpi, &mgr->payloads[i]);
1949		- req_payload.payload_state = mgr->payloads[i].payload_state;
1950		- mgr->payloads[i].start_slot = 0;
	3429	+ drm_dp_create_payload_step1(mgr, vcpi->vcpi,
	3430	+ &req_payload);
	3431	+ payload->num_slots = req_payload.num_slots;
	3432	+ payload->vcpi = req_payload.vcpi;
	3433	+
	3434	+ } else if (payload->num_slots) {
	3435	+ payload->num_slots = 0;
	3436	+ drm_dp_destroy_payload_step1(mgr, port,
	3437	+ payload->vcpi,
	3438	+ payload);
	3439	+ req_payload.payload_state =
	3440	+ payload->payload_state;
	3441	+ payload->start_slot = 0;
1951	3442	}
1952		- mgr->payloads[i].payload_state = req_payload.payload_state;
	3443	+ payload->payload_state = req_payload.payload_state;
1953	3444	}
1954	3445	cur_slots += req_payload.num_slots;
1955	3446
1956		- if (port)
1957		- drm_dp_put_port(port);
	3447	+ if (put_port)
	3448	+ drm_dp_mst_topology_put_port(port);
1958	3449	}
1959	3450
1960		- for (i = 0; i < mgr->max_payloads; i++) {
1961		- if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1962		- DRM_DEBUG_KMS("removing payload %d\n", i);
1963		- for (j = i; j < mgr->max_payloads - 1; j++) {
1964		- memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
1965		- mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
1966		- if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
1967		- set_bit(j + 1, &mgr->payload_mask);
1968		- } else {
1969		- clear_bit(j + 1, &mgr->payload_mask);
1970		- }
1971		- }
1972		- memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
1973		- mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
1974		- clear_bit(mgr->max_payloads, &mgr->payload_mask);
1975		-
	3451	+ for (i = 0; i < mgr->max_payloads; /* do nothing */) {
	3452	+ if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
	3453	+ i++;
	3454	+ continue;
1976	3455	}
	3456	+
	3457	+ DRM_DEBUG_KMS("removing payload %d\n", i);
	3458	+ for (j = i; j < mgr->max_payloads - 1; j++) {
	3459	+ mgr->payloads[j] = mgr->payloads[j + 1];
	3460	+ mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
	3461	+
	3462	+ if (mgr->proposed_vcpis[j] &&
	3463	+ mgr->proposed_vcpis[j]->num_slots) {
	3464	+ set_bit(j + 1, &mgr->payload_mask);
	3465	+ } else {
	3466	+ clear_bit(j + 1, &mgr->payload_mask);
	3467	+ }
	3468	+ }
	3469	+
	3470	+ memset(&mgr->payloads[mgr->max_payloads - 1], 0,
	3471	+ sizeof(struct drm_dp_payload));
	3472	+ mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
	3473	+ clear_bit(mgr->max_payloads, &mgr->payload_mask);
1977	3474	}
1978	3475	mutex_unlock(&mgr->payload_lock);
1979	3476
..	..	@@ -1995,6 +3492,8 @@
1995	3492	struct drm_dp_mst_port *port;
1996	3493	int i;
1997	3494	int ret = 0;
	3495	+ bool skip;
	3496	+
1998	3497	mutex_lock(&mgr->payload_lock);
1999	3498	for (i = 0; i < mgr->max_payloads; i++) {
2000	3499
..	..	@@ -2002,6 +3501,13 @@
2002	3501	continue;
2003	3502
2004	3503	port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
	3504	+
	3505	+ mutex_lock(&mgr->lock);
	3506	+ skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
	3507	+ mutex_unlock(&mgr->lock);
	3508	+
	3509	+ if (skip)
	3510	+ continue;
2005	3511
2006	3512	DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
2007	3513	if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
..	..	@@ -2019,36 +3525,15 @@
2019	3525	}
2020	3526	EXPORT_SYMBOL(drm_dp_update_payload_part2);
2021	3527
2022		-int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
2023		- struct drm_dp_mst_port *port,
2024		- int offset, int size, u8 *bytes)
	3528	+static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
	3529	+ struct drm_dp_mst_port *port,
	3530	+ int offset, int size, u8 *bytes)
2025	3531	{
2026		- int len;
2027		- struct drm_dp_sideband_msg_tx *txmsg;
2028		-
2029		- txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2030		- if (!txmsg)
2031		- return -ENOMEM;
2032		-
2033		- len = build_dpcd_read(txmsg, port->port_num, offset, size);
2034		- txmsg->dst = port->parent;
2035		-
2036		- drm_dp_queue_down_tx(mgr, txmsg);
2037		-
2038		- return 0;
2039		-}
2040		-EXPORT_SYMBOL_GPL(drm_dp_send_dpcd_read);
2041		-
2042		-int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
2043		- struct drm_dp_mst_port *port,
2044		- int offset, int size, u8 *bytes)
2045		-{
2046		- int len;
2047		- int ret;
	3532	+ int ret = 0;
2048	3533	struct drm_dp_sideband_msg_tx *txmsg;
2049	3534	struct drm_dp_mst_branch *mstb;
2050	3535
2051		- mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
	3536	+ mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
2052	3537	if (!mstb)
2053	3538	return -EINVAL;
2054	3539
..	..	@@ -2058,45 +3543,82 @@
2058	3543	goto fail_put;
2059	3544	}
2060	3545
2061		- len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
	3546	+ build_dpcd_read(txmsg, port->port_num, offset, size);
	3547	+ txmsg->dst = port->parent;
	3548	+
	3549	+ drm_dp_queue_down_tx(mgr, txmsg);
	3550	+
	3551	+ ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
	3552	+ if (ret < 0)
	3553	+ goto fail_free;
	3554	+
	3555	+ /* DPCD read should never be NACKed */
	3556	+ if (txmsg->reply.reply_type == 1) {
	3557	+ DRM_ERROR("mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
	3558	+ mstb, port->port_num, offset, size);
	3559	+ ret = -EIO;
	3560	+ goto fail_free;
	3561	+ }
	3562	+
	3563	+ if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
	3564	+ ret = -EPROTO;
	3565	+ goto fail_free;
	3566	+ }
	3567	+
	3568	+ ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
	3569	+ size);
	3570	+ memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
	3571	+
	3572	+fail_free:
	3573	+ kfree(txmsg);
	3574	+fail_put:
	3575	+ drm_dp_mst_topology_put_mstb(mstb);
	3576	+
	3577	+ return ret;
	3578	+}
	3579	+
	3580	+static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
	3581	+ struct drm_dp_mst_port *port,
	3582	+ int offset, int size, u8 *bytes)
	3583	+{
	3584	+ int ret;
	3585	+ struct drm_dp_sideband_msg_tx *txmsg;
	3586	+ struct drm_dp_mst_branch *mstb;
	3587	+
	3588	+ mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
	3589	+ if (!mstb)
	3590	+ return -EINVAL;
	3591	+
	3592	+ txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
	3593	+ if (!txmsg) {
	3594	+ ret = -ENOMEM;
	3595	+ goto fail_put;
	3596	+ }
	3597	+
	3598	+ build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
2062	3599	txmsg->dst = mstb;
2063	3600
2064	3601	drm_dp_queue_down_tx(mgr, txmsg);
2065	3602
2066	3603	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2067	3604	if (ret > 0) {
2068		- if (txmsg->reply.reply_type == 1) {
2069		- ret = -EINVAL;
2070		- } else
2071		- ret = 0;
	3605	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
	3606	+ ret = -EIO;
	3607	+ else
	3608	+ ret = size;
2072	3609	}
	3610	+
2073	3611	kfree(txmsg);
2074	3612	fail_put:
2075		- drm_dp_put_mst_branch_device(mstb);
	3613	+ drm_dp_mst_topology_put_mstb(mstb);
2076	3614	return ret;
2077	3615	}
2078		-EXPORT_SYMBOL_GPL(drm_dp_send_dpcd_write);
2079		-
2080		-int drm_dp_mst_get_max_sdp_streams_supported(
2081		- struct drm_dp_mst_topology_mgr *mgr,
2082		- struct drm_dp_mst_port *port)
2083		-{
2084		- int ret = -1;
2085		-
2086		- port = drm_dp_get_validated_port_ref(mgr, port);
2087		- if (!port)
2088		- return ret;
2089		- ret = port->num_sdp_streams;
2090		- drm_dp_put_port(port);
2091		- return ret;
2092		-}
2093		-EXPORT_SYMBOL_GPL(drm_dp_mst_get_max_sdp_streams_supported);
2094	3616
2095	3617	static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
2096	3618	{
2097	3619	struct drm_dp_sideband_msg_reply_body reply;
2098	3620
2099		- reply.reply_type = 0;
	3621	+ reply.reply_type = DP_SIDEBAND_REPLY_ACK;
2100	3622	reply.req_type = req_type;
2101	3623	drm_dp_encode_sideband_reply(&reply, msg);
2102	3624	return 0;
..	..	@@ -2104,7 +3626,7 @@
2104	3626
2105	3627	static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
2106	3628	struct drm_dp_mst_branch *mstb,
2107		- int req_type, int seqno, bool broadcast)
	3629	+ int req_type, bool broadcast)
2108	3630	{
2109	3631	struct drm_dp_sideband_msg_tx *txmsg;
2110	3632
..	..	@@ -2113,44 +3635,59 @@
2113	3635	return -ENOMEM;
2114	3636
2115	3637	txmsg->dst = mstb;
2116		- txmsg->seqno = seqno;
2117	3638	drm_dp_encode_up_ack_reply(txmsg, req_type);
2118	3639
2119	3640	mutex_lock(&mgr->qlock);
2120		-
2121		- process_single_up_tx_qlock(mgr, txmsg);
2122		-
	3641	+ /* construct a chunk from the first msg in the tx_msg queue */
	3642	+ process_single_tx_qlock(mgr, txmsg, true);
2123	3643	mutex_unlock(&mgr->qlock);
2124	3644
2125	3645	kfree(txmsg);
2126	3646	return 0;
2127	3647	}
2128	3648
2129		-static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
2130		- int dp_link_count,
2131		- int *out)
	3649	+/**
	3650	+ * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
	3651	+ * @link_rate: link rate in 10kbits/s units
	3652	+ * @link_lane_count: lane count
	3653	+ *
	3654	+ * Calculate the total bandwidth of a MultiStream Transport link. The returned
	3655	+ * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
	3656	+ * convert the number of PBNs required for a given stream to the number of
	3657	+ * timeslots this stream requires in each MTP.
	3658	+ */
	3659	+int drm_dp_get_vc_payload_bw(int link_rate, int link_lane_count)
2132	3660	{
2133		- switch (dp_link_bw) {
2134		- default:
2135		- DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
2136		- dp_link_bw, dp_link_count);
	3661	+ if (link_rate == 0 \|\| link_lane_count == 0)
	3662	+ DRM_DEBUG_KMS("invalid link rate/lane count: (%d / %d)\n",
	3663	+ link_rate, link_lane_count);
	3664	+
	3665	+ /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
	3666	+ return link_rate * link_lane_count / 54000;
	3667	+}
	3668	+EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
	3669	+
	3670	+/**
	3671	+ * drm_dp_read_mst_cap() - check whether or not a sink supports MST
	3672	+ * @aux: The DP AUX channel to use
	3673	+ * @dpcd: A cached copy of the DPCD capabilities for this sink
	3674	+ *
	3675	+ * Returns: %True if the sink supports MST, %false otherwise
	3676	+ */
	3677	+bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
	3678	+ const u8 dpcd[DP_RECEIVER_CAP_SIZE])
	3679	+{
	3680	+ u8 mstm_cap;
	3681	+
	3682	+ if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
2137	3683	return false;
2138	3684
2139		- case DP_LINK_BW_1_62:
2140		- out = 3 dp_link_count;
2141		- break;
2142		- case DP_LINK_BW_2_7:
2143		- out = 5 dp_link_count;
2144		- break;
2145		- case DP_LINK_BW_5_4:
2146		- out = 10 dp_link_count;
2147		- break;
2148		- case DP_LINK_BW_8_1:
2149		- out = 15 dp_link_count;
2150		- break;
2151		- }
2152		- return true;
	3685	+ if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
	3686	+ return false;
	3687	+
	3688	+ return mstm_cap & DP_MST_CAP;
2153	3689	}
	3690	+EXPORT_SYMBOL(drm_dp_read_mst_cap);
2154	3691
2155	3692	/**
2156	3693	* drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
..	..	@@ -2173,6 +3710,8 @@
2173	3710	mgr->mst_state = mst_state;
2174	3711	/* set the device into MST mode */
2175	3712	if (mst_state) {
	3713	+ struct drm_dp_payload reset_pay;
	3714	+
2176	3715	WARN_ON(mgr->mst_primary);
2177	3716
2178	3717	/* get dpcd info */
..	..	@@ -2182,9 +3721,9 @@
2182	3721	goto out_unlock;
2183	3722	}
2184	3723
2185		- if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
2186		- mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
2187		- &mgr->pbn_div)) {
	3724	+ mgr->pbn_div = drm_dp_get_vc_payload_bw(drm_dp_bw_code_to_link_rate(mgr->dpcd[1]),
	3725	+ mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
	3726	+ if (mgr->pbn_div == 0) {
2188	3727	ret = -EINVAL;
2189	3728	goto out_unlock;
2190	3729	}
..	..	@@ -2199,20 +3738,18 @@
2199	3738
2200	3739	/* give this the main reference */
2201	3740	mgr->mst_primary = mstb;
2202		- kref_get(&mgr->mst_primary->kref);
	3741	+ drm_dp_mst_topology_get_mstb(mgr->mst_primary);
2203	3742
2204	3743	ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2205		- DP_MST_EN \| DP_UP_REQ_EN \| DP_UPSTREAM_IS_SRC);
2206		- if (ret < 0) {
	3744	+ DP_MST_EN \|
	3745	+ DP_UP_REQ_EN \|
	3746	+ DP_UPSTREAM_IS_SRC);
	3747	+ if (ret < 0)
2207	3748	goto out_unlock;
2208		- }
2209	3749
2210		- {
2211		- struct drm_dp_payload reset_pay;
2212		- reset_pay.start_slot = 0;
2213		- reset_pay.num_slots = 0x3f;
2214		- drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2215		- }
	3750	+ reset_pay.start_slot = 0;
	3751	+ reset_pay.num_slots = 0x3f;
	3752	+ drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2216	3753
2217	3754	queue_work(system_long_wq, &mgr->work);
2218	3755
..	..	@@ -2231,17 +3768,34 @@
2231	3768	mgr->payload_mask = 0;
2232	3769	set_bit(0, &mgr->payload_mask);
2233	3770	mgr->vcpi_mask = 0;
	3771	+ mgr->payload_id_table_cleared = false;
	3772	+
	3773	+ memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
	3774	+ memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
2234	3775	}
2235	3776
2236	3777	out_unlock:
2237	3778	mutex_unlock(&mgr->lock);
2238	3779	mutex_unlock(&mgr->payload_lock);
2239	3780	if (mstb)
2240		- drm_dp_put_mst_branch_device(mstb);
	3781	+ drm_dp_mst_topology_put_mstb(mstb);
2241	3782	return ret;
2242	3783
2243	3784	}
2244	3785	EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
	3786	+
	3787	+static void
	3788	+drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
	3789	+{
	3790	+ struct drm_dp_mst_port *port;
	3791	+
	3792	+ /* The link address will need to be re-sent on resume */
	3793	+ mstb->link_address_sent = false;
	3794	+
	3795	+ list_for_each_entry(port, &mstb->ports, next)
	3796	+ if (port->mstb)
	3797	+ drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
	3798	+}
2245	3799
2246	3800	/**
2247	3801	* drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
..	..	@@ -2256,91 +3810,154 @@
2256	3810	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2257	3811	DP_MST_EN \| DP_UPSTREAM_IS_SRC);
2258	3812	mutex_unlock(&mgr->lock);
	3813	+ flush_work(&mgr->up_req_work);
2259	3814	flush_work(&mgr->work);
2260		- flush_work(&mgr->destroy_connector_work);
	3815	+ flush_work(&mgr->delayed_destroy_work);
	3816	+
	3817	+ mutex_lock(&mgr->lock);
	3818	+ if (mgr->mst_state && mgr->mst_primary)
	3819	+ drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
	3820	+ mutex_unlock(&mgr->lock);
2261	3821	}
2262	3822	EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
2263	3823
2264	3824	/**
2265	3825	* drm_dp_mst_topology_mgr_resume() - resume the MST manager
2266	3826	* @mgr: manager to resume
	3827	+ * @sync: whether or not to perform topology reprobing synchronously
2267	3828	*
2268	3829	* This will fetch DPCD and see if the device is still there,
2269	3830	* if it is, it will rewrite the MSTM control bits, and return.
2270	3831	*
2271		- * if the device fails this returns -1, and the driver should do
	3832	+ * If the device fails this returns -1, and the driver should do
2272	3833	* a full MST reprobe, in case we were undocked.
	3834	+ *
	3835	+ * During system resume (where it is assumed that the driver will be calling
	3836	+ * drm_atomic_helper_resume()) this function should be called beforehand with
	3837	+ * @sync set to true. In contexts like runtime resume where the driver is not
	3838	+ * expected to be calling drm_atomic_helper_resume(), this function should be
	3839	+ * called with @sync set to false in order to avoid deadlocking.
	3840	+ *
	3841	+ * Returns: -1 if the MST topology was removed while we were suspended, 0
	3842	+ * otherwise.
2273	3843	*/
2274		-int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
	3844	+int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
	3845	+ bool sync)
2275	3846	{
2276		- int ret = 0;
	3847	+ int ret;
	3848	+ u8 guid[16];
2277	3849
2278	3850	mutex_lock(&mgr->lock);
	3851	+ if (!mgr->mst_primary)
	3852	+ goto out_fail;
2279	3853
2280		- if (mgr->mst_primary) {
2281		- int sret;
2282		- u8 guid[16];
	3854	+ ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
	3855	+ DP_RECEIVER_CAP_SIZE);
	3856	+ if (ret != DP_RECEIVER_CAP_SIZE) {
	3857	+ DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
	3858	+ goto out_fail;
	3859	+ }
2283	3860
2284		- sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2285		- if (sret != DP_RECEIVER_CAP_SIZE) {
2286		- DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2287		- ret = -1;
2288		- goto out_unlock;
2289		- }
	3861	+ ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
	3862	+ DP_MST_EN \|
	3863	+ DP_UP_REQ_EN \|
	3864	+ DP_UPSTREAM_IS_SRC);
	3865	+ if (ret < 0) {
	3866	+ DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
	3867	+ goto out_fail;
	3868	+ }
2290	3869
2291		- ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2292		- DP_MST_EN \| DP_UP_REQ_EN \| DP_UPSTREAM_IS_SRC);
2293		- if (ret < 0) {
2294		- DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2295		- ret = -1;
2296		- goto out_unlock;
2297		- }
	3870	+ /* Some hubs forget their guids after they resume */
	3871	+ ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
	3872	+ if (ret != 16) {
	3873	+ DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
	3874	+ goto out_fail;
	3875	+ }
2298	3876
2299		- /* Some hubs forget their guids after they resume */
2300		- sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
2301		- if (sret != 16) {
2302		- DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2303		- ret = -1;
2304		- goto out_unlock;
2305		- }
2306		- drm_dp_check_mstb_guid(mgr->mst_primary, guid);
	3877	+ ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
	3878	+ if (ret) {
	3879	+ DRM_DEBUG_KMS("check mstb failed - undocked during suspend?\n");
	3880	+ goto out_fail;
	3881	+ }
2307	3882
2308		- ret = 0;
2309		- } else
2310		- ret = -1;
2311		-
2312		-out_unlock:
	3883	+ /*
	3884	+ * For the final step of resuming the topology, we need to bring the
	3885	+ * state of our in-memory topology back into sync with reality. So,
	3886	+ * restart the probing process as if we're probing a new hub
	3887	+ */
	3888	+ queue_work(system_long_wq, &mgr->work);
2313	3889	mutex_unlock(&mgr->lock);
2314		- return ret;
	3890	+
	3891	+ if (sync) {
	3892	+ DRM_DEBUG_KMS("Waiting for link probe work to finish re-syncing topology...\n");
	3893	+ flush_work(&mgr->work);
	3894	+ }
	3895	+
	3896	+ return 0;
	3897	+
	3898	+out_fail:
	3899	+ mutex_unlock(&mgr->lock);
	3900	+ return -1;
2315	3901	}
2316	3902	EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2317	3903
2318		-static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
	3904	+static bool
	3905	+drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
	3906	+ struct drm_dp_mst_branch **mstb)
2319	3907	{
2320	3908	int len;
2321	3909	u8 replyblock[32];
2322		- int replylen, origlen, curreply;
	3910	+ int replylen, curreply;
2323	3911	int ret;
2324		- struct drm_dp_sideband_msg_rx *msg;
2325		- int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2326		- msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
	3912	+ u8 hdrlen;
	3913	+ struct drm_dp_sideband_msg_hdr hdr;
	3914	+ struct drm_dp_sideband_msg_rx *msg =
	3915	+ up ? &mgr->up_req_recv : &mgr->down_rep_recv;
	3916	+ int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
	3917	+ DP_SIDEBAND_MSG_DOWN_REP_BASE;
	3918	+
	3919	+ if (!up)
	3920	+ *mstb = NULL;
2327	3921
2328	3922	len = min(mgr->max_dpcd_transaction_bytes, 16);
2329		- ret = drm_dp_dpcd_read(mgr->aux, basereg,
2330		- replyblock, len);
	3923	+ ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
2331	3924	if (ret != len) {
2332	3925	DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2333	3926	return false;
2334	3927	}
2335		- ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
	3928	+
	3929	+ ret = drm_dp_decode_sideband_msg_hdr(&hdr, replyblock, len, &hdrlen);
	3930	+ if (ret == false) {
	3931	+ print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
	3932	+ 1, replyblock, len, false);
	3933	+ DRM_DEBUG_KMS("ERROR: failed header\n");
	3934	+ return false;
	3935	+ }
	3936	+
	3937	+ if (!up) {
	3938	+ /* Caller is responsible for giving back this reference */
	3939	+ *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
	3940	+ if (!*mstb) {
	3941	+ DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
	3942	+ hdr.lct);
	3943	+ return false;
	3944	+ }
	3945	+ }
	3946	+
	3947	+ if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
	3948	+ DRM_DEBUG_KMS("sideband msg set header failed %d\n",
	3949	+ replyblock[0]);
	3950	+ return false;
	3951	+ }
	3952	+
	3953	+ replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
	3954	+ ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
2336	3955	if (!ret) {
2337	3956	DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2338	3957	return false;
2339	3958	}
2340		- replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2341	3959
2342		- origlen = replylen;
2343		- replylen -= len;
	3960	+ replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
2344	3961	curreply = len;
2345	3962	while (replylen > 0) {
2346	3963	len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
..	..	@@ -2352,7 +3969,7 @@
2352	3969	return false;
2353	3970	}
2354	3971
2355		- ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
	3972	+ ret = drm_dp_sideband_append_payload(msg, replyblock, len);
2356	3973	if (!ret) {
2357	3974	DRM_DEBUG_KMS("failed to build sideband msg\n");
2358	3975	return false;
..	..	@@ -2366,131 +3983,194 @@
2366	3983
2367	3984	static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2368	3985	{
2369		- int ret = 0;
	3986	+ struct drm_dp_sideband_msg_tx *txmsg;
	3987	+ struct drm_dp_mst_branch *mstb = NULL;
	3988	+ struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
2370	3989
2371		- if (!drm_dp_get_one_sb_msg(mgr, false)) {
2372		- memset(&mgr->down_rep_recv, 0,
2373		- sizeof(struct drm_dp_sideband_msg_rx));
2374		- return 0;
	3990	+ if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
	3991	+ goto out_clear_reply;
	3992	+
	3993	+ /* Multi-packet message transmission, don't clear the reply */
	3994	+ if (!msg->have_eomt)
	3995	+ goto out;
	3996	+
	3997	+ /* find the message */
	3998	+ mutex_lock(&mgr->qlock);
	3999	+ txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
	4000	+ struct drm_dp_sideband_msg_tx, next);
	4001	+ mutex_unlock(&mgr->qlock);
	4002	+
	4003	+ /* Were we actually expecting a response, and from this mstb? */
	4004	+ if (!txmsg \|\| txmsg->dst != mstb) {
	4005	+ struct drm_dp_sideband_msg_hdr *hdr;
	4006	+
	4007	+ hdr = &msg->initial_hdr;
	4008	+ DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
	4009	+ mstb, hdr->seqno, hdr->lct, hdr->rad[0],
	4010	+ msg->msg[0]);
	4011	+ goto out_clear_reply;
2375	4012	}
2376	4013
2377		- if (mgr->down_rep_recv.have_eomt) {
2378		- struct drm_dp_sideband_msg_tx *txmsg;
2379		- struct drm_dp_mst_branch *mstb;
2380		- int slot = -1;
2381		- mstb = drm_dp_get_mst_branch_device(mgr,
2382		- mgr->down_rep_recv.initial_hdr.lct,
2383		- mgr->down_rep_recv.initial_hdr.rad);
	4014	+ drm_dp_sideband_parse_reply(msg, &txmsg->reply);
2384	4015
2385		- if (!mstb) {
2386		- DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2387		- memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2388		- return 0;
2389		- }
2390		-
2391		- /* find the message */
2392		- slot = mgr->down_rep_recv.initial_hdr.seqno;
2393		- mutex_lock(&mgr->qlock);
2394		- txmsg = mstb->tx_slots[slot];
2395		- /* remove from slots */
2396		- mutex_unlock(&mgr->qlock);
2397		-
2398		- if (!txmsg) {
2399		- DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2400		- mstb,
2401		- mgr->down_rep_recv.initial_hdr.seqno,
2402		- mgr->down_rep_recv.initial_hdr.lct,
2403		- mgr->down_rep_recv.initial_hdr.rad[0],
2404		- mgr->down_rep_recv.msg[0]);
2405		- drm_dp_put_mst_branch_device(mstb);
2406		- memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2407		- return 0;
2408		- }
2409		-
2410		- drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2411		- if (txmsg->reply.reply_type == 1) {
2412		- DRM_DEBUG_KMS("Got NAK reply: req 0x%02x, reason 0x%02x, nak data 0x%02x\n", txmsg->reply.req_type, txmsg->reply.u.nak.reason, txmsg->reply.u.nak.nak_data);
2413		- }
2414		-
2415		- memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2416		- drm_dp_put_mst_branch_device(mstb);
2417		-
2418		- mutex_lock(&mgr->qlock);
2419		- txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2420		- mstb->tx_slots[slot] = NULL;
2421		- mutex_unlock(&mgr->qlock);
2422		-
2423		- wake_up_all(&mgr->tx_waitq);
	4016	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
	4017	+ DRM_DEBUG_KMS("Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
	4018	+ txmsg->reply.req_type,
	4019	+ drm_dp_mst_req_type_str(txmsg->reply.req_type),
	4020	+ txmsg->reply.u.nak.reason,
	4021	+ drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
	4022	+ txmsg->reply.u.nak.nak_data);
2424	4023	}
2425		- return ret;
	4024	+
	4025	+ memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
	4026	+ drm_dp_mst_topology_put_mstb(mstb);
	4027	+
	4028	+ mutex_lock(&mgr->qlock);
	4029	+ txmsg->state = DRM_DP_SIDEBAND_TX_RX;
	4030	+ list_del(&txmsg->next);
	4031	+ mutex_unlock(&mgr->qlock);
	4032	+
	4033	+ wake_up_all(&mgr->tx_waitq);
	4034	+
	4035	+ return 0;
	4036	+
	4037	+out_clear_reply:
	4038	+ memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
	4039	+out:
	4040	+ if (mstb)
	4041	+ drm_dp_mst_topology_put_mstb(mstb);
	4042	+
	4043	+ return 0;
	4044	+}
	4045	+
	4046	+static inline bool
	4047	+drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
	4048	+ struct drm_dp_pending_up_req *up_req)
	4049	+{
	4050	+ struct drm_dp_mst_branch *mstb = NULL;
	4051	+ struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
	4052	+ struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
	4053	+ bool hotplug = false;
	4054	+
	4055	+ if (hdr->broadcast) {
	4056	+ const u8 *guid = NULL;
	4057	+
	4058	+ if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
	4059	+ guid = msg->u.conn_stat.guid;
	4060	+ else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
	4061	+ guid = msg->u.resource_stat.guid;
	4062	+
	4063	+ if (guid)
	4064	+ mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
	4065	+ } else {
	4066	+ mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
	4067	+ }
	4068	+
	4069	+ if (!mstb) {
	4070	+ DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
	4071	+ hdr->lct);
	4072	+ return false;
	4073	+ }
	4074	+
	4075	+ /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
	4076	+ if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
	4077	+ drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
	4078	+ hotplug = true;
	4079	+ }
	4080	+
	4081	+ drm_dp_mst_topology_put_mstb(mstb);
	4082	+ return hotplug;
	4083	+}
	4084	+
	4085	+static void drm_dp_mst_up_req_work(struct work_struct *work)
	4086	+{
	4087	+ struct drm_dp_mst_topology_mgr *mgr =
	4088	+ container_of(work, struct drm_dp_mst_topology_mgr,
	4089	+ up_req_work);
	4090	+ struct drm_dp_pending_up_req *up_req;
	4091	+ bool send_hotplug = false;
	4092	+
	4093	+ mutex_lock(&mgr->probe_lock);
	4094	+ while (true) {
	4095	+ mutex_lock(&mgr->up_req_lock);
	4096	+ up_req = list_first_entry_or_null(&mgr->up_req_list,
	4097	+ struct drm_dp_pending_up_req,
	4098	+ next);
	4099	+ if (up_req)
	4100	+ list_del(&up_req->next);
	4101	+ mutex_unlock(&mgr->up_req_lock);
	4102	+
	4103	+ if (!up_req)
	4104	+ break;
	4105	+
	4106	+ send_hotplug \|= drm_dp_mst_process_up_req(mgr, up_req);
	4107	+ kfree(up_req);
	4108	+ }
	4109	+ mutex_unlock(&mgr->probe_lock);
	4110	+
	4111	+ if (send_hotplug)
	4112	+ drm_kms_helper_hotplug_event(mgr->dev);
2426	4113	}
2427	4114
2428	4115	static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2429	4116	{
2430		- int ret = 0;
	4117	+ struct drm_dp_pending_up_req *up_req;
2431	4118
2432		- if (!drm_dp_get_one_sb_msg(mgr, true)) {
2433		- memset(&mgr->up_req_recv, 0,
2434		- sizeof(struct drm_dp_sideband_msg_rx));
	4119	+ if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
	4120	+ goto out;
	4121	+
	4122	+ if (!mgr->up_req_recv.have_eomt)
2435	4123	return 0;
	4124	+
	4125	+ up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
	4126	+ if (!up_req) {
	4127	+ DRM_ERROR("Not enough memory to process MST up req\n");
	4128	+ return -ENOMEM;
	4129	+ }
	4130	+ INIT_LIST_HEAD(&up_req->next);
	4131	+
	4132	+ drm_dp_sideband_parse_req(&mgr->up_req_recv, &up_req->msg);
	4133	+
	4134	+ if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
	4135	+ up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
	4136	+ DRM_DEBUG_KMS("Received unknown up req type, ignoring: %x\n",
	4137	+ up_req->msg.req_type);
	4138	+ kfree(up_req);
	4139	+ goto out;
2436	4140	}
2437	4141
2438		- if (mgr->up_req_recv.have_eomt) {
2439		- struct drm_dp_sideband_msg_req_body msg;
2440		- struct drm_dp_mst_branch *mstb = NULL;
2441		- bool seqno;
	4142	+ drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
	4143	+ false);
2442	4144
2443		- if (!mgr->up_req_recv.initial_hdr.broadcast) {
2444		- mstb = drm_dp_get_mst_branch_device(mgr,
2445		- mgr->up_req_recv.initial_hdr.lct,
2446		- mgr->up_req_recv.initial_hdr.rad);
2447		- if (!mstb) {
2448		- DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2449		- memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2450		- return 0;
2451		- }
2452		- }
	4145	+ if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
	4146	+ const struct drm_dp_connection_status_notify *conn_stat =
	4147	+ &up_req->msg.u.conn_stat;
2453	4148
2454		- seqno = mgr->up_req_recv.initial_hdr.seqno;
2455		- drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
	4149	+ DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
	4150	+ conn_stat->port_number,
	4151	+ conn_stat->legacy_device_plug_status,
	4152	+ conn_stat->displayport_device_plug_status,
	4153	+ conn_stat->message_capability_status,
	4154	+ conn_stat->input_port,
	4155	+ conn_stat->peer_device_type);
	4156	+ } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
	4157	+ const struct drm_dp_resource_status_notify *res_stat =
	4158	+ &up_req->msg.u.resource_stat;
2456	4159
2457		- if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2458		- drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2459		-
2460		- if (!mstb)
2461		- mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
2462		-
2463		- if (!mstb) {
2464		- DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2465		- memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2466		- return 0;
2467		- }
2468		-
2469		- drm_dp_update_port(mstb, &msg.u.conn_stat);
2470		-
2471		- DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);
2472		- (*mgr->cbs->hotplug)(mgr);
2473		-
2474		- } else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
2475		- drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2476		- if (!mstb)
2477		- mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
2478		-
2479		- if (!mstb) {
2480		- DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2481		- memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2482		- return 0;
2483		- }
2484		-
2485		- DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
2486		- }
2487		-
2488		- if (mstb)
2489		- drm_dp_put_mst_branch_device(mstb);
2490		-
2491		- memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
	4160	+ DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n",
	4161	+ res_stat->port_number,
	4162	+ res_stat->available_pbn);
2492	4163	}
2493		- return ret;
	4164	+
	4165	+ up_req->hdr = mgr->up_req_recv.initial_hdr;
	4166	+ mutex_lock(&mgr->up_req_lock);
	4167	+ list_add_tail(&up_req->next, &mgr->up_req_list);
	4168	+ mutex_unlock(&mgr->up_req_lock);
	4169	+ queue_work(system_long_wq, &mgr->up_req_work);
	4170	+
	4171	+out:
	4172	+ memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
	4173	+ return 0;
2494	4174	}
2495	4175
2496	4176	/**
..	..	@@ -2534,32 +4214,44 @@
2534	4214	/**
2535	4215	* drm_dp_mst_detect_port() - get connection status for an MST port
2536	4216	* @connector: DRM connector for this port
	4217	+ * @ctx: The acquisition context to use for grabbing locks
2537	4218	* @mgr: manager for this port
2538		- * @port: unverified pointer to a port
	4219	+ * @port: pointer to a port
2539	4220	*
2540		- * This returns the current connection state for a port. It validates the
2541		- * port pointer still exists so the caller doesn't require a reference
	4221	+ * This returns the current connection state for a port.
2542	4222	*/
2543		-enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
2544		- struct drm_dp_mst_topology_mgr mgr, struct drm_dp_mst_port port)
	4223	+int
	4224	+drm_dp_mst_detect_port(struct drm_connector *connector,
	4225	+ struct drm_modeset_acquire_ctx *ctx,
	4226	+ struct drm_dp_mst_topology_mgr *mgr,
	4227	+ struct drm_dp_mst_port *port)
2545	4228	{
2546		- enum drm_connector_status status = connector_status_disconnected;
	4229	+ int ret;
2547	4230
2548		- /* we need to search for the port in the mgr in case its gone */
2549		- port = drm_dp_get_validated_port_ref(mgr, port);
	4231	+ /* we need to search for the port in the mgr in case it's gone */
	4232	+ port = drm_dp_mst_topology_get_port_validated(mgr, port);
2550	4233	if (!port)
2551	4234	return connector_status_disconnected;
	4235	+
	4236	+ ret = drm_modeset_lock(&mgr->base.lock, ctx);
	4237	+ if (ret)
	4238	+ goto out;
	4239	+
	4240	+ ret = connector_status_disconnected;
2552	4241
2553	4242	if (!port->ddps)
2554	4243	goto out;
2555	4244
2556	4245	switch (port->pdt) {
2557	4246	case DP_PEER_DEVICE_NONE:
	4247	+ break;
2558	4248	case DP_PEER_DEVICE_MST_BRANCHING:
	4249	+ if (!port->mcs)
	4250	+ ret = connector_status_connected;
2559	4251	break;
2560	4252
2561	4253	case DP_PEER_DEVICE_SST_SINK:
2562		- status = connector_status_connected;
	4254	+ ret = connector_status_connected;
2563	4255	/* for logical ports - cache the EDID */
2564	4256	if (port->port_num >= 8 && !port->cached_edid) {
2565	4257	port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
..	..	@@ -2567,49 +4259,14 @@
2567	4259	break;
2568	4260	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2569	4261	if (port->ldps)
2570		- status = connector_status_connected;
	4262	+ ret = connector_status_connected;
2571	4263	break;
2572	4264	}
2573	4265	out:
2574		- drm_dp_put_port(port);
2575		- return status;
	4266	+ drm_dp_mst_topology_put_port(port);
	4267	+ return ret;
2576	4268	}
2577	4269	EXPORT_SYMBOL(drm_dp_mst_detect_port);
2578		-
2579		-/**
2580		- * drm_dp_mst_port_has_audio() - Check whether port has audio capability or not
2581		- * @mgr: manager for this port
2582		- * @port: unverified pointer to a port.
2583		- *
2584		- * This returns whether the port supports audio or not.
2585		- */
2586		-bool drm_dp_mst_port_has_audio(struct drm_dp_mst_topology_mgr *mgr,
2587		- struct drm_dp_mst_port *port)
2588		-{
2589		- bool ret = false;
2590		-
2591		- port = drm_dp_get_validated_port_ref(mgr, port);
2592		- if (!port)
2593		- return ret;
2594		- ret = port->has_audio;
2595		- drm_dp_put_port(port);
2596		- return ret;
2597		-}
2598		-EXPORT_SYMBOL(drm_dp_mst_port_has_audio);
2599		-
2600		-bool drm_dp_mst_has_fec(struct drm_dp_mst_topology_mgr *mgr,
2601		- struct drm_dp_mst_port *port)
2602		-{
2603		- bool ret = false;
2604		-
2605		- port = drm_dp_get_validated_port_ref(mgr, port);
2606		- if (!port)
2607		- return ret;
2608		- ret = port->fec_capable;
2609		- drm_dp_put_port(port);
2610		- return ret;
2611		-}
2612		-EXPORT_SYMBOL_GPL(drm_dp_mst_has_fec);
2613	4270
2614	4271	/**
2615	4272	* drm_dp_mst_get_edid() - get EDID for an MST port
..	..	@@ -2625,8 +4282,8 @@
2625	4282	{
2626	4283	struct edid *edid = NULL;
2627	4284
2628		- /* we need to search for the port in the mgr in case its gone */
2629		- port = drm_dp_get_validated_port_ref(mgr, port);
	4285	+ /* we need to search for the port in the mgr in case it's gone */
	4286	+ port = drm_dp_mst_topology_get_port_validated(mgr, port);
2630	4287	if (!port)
2631	4288	return NULL;
2632	4289
..	..	@@ -2634,18 +4291,24 @@
2634	4291	edid = drm_edid_duplicate(port->cached_edid);
2635	4292	else {
2636	4293	edid = drm_get_edid(connector, &port->aux.ddc);
2637		- drm_connector_set_tile_property(connector);
2638	4294	}
2639	4295	port->has_audio = drm_detect_monitor_audio(edid);
2640		- drm_dp_put_port(port);
	4296	+ drm_dp_mst_topology_put_port(port);
2641	4297	return edid;
2642	4298	}
2643	4299	EXPORT_SYMBOL(drm_dp_mst_get_edid);
2644	4300
2645	4301	/**
2646		- * drm_dp_find_vcpi_slots() - find slots for this PBN value
	4302	+ * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
2647	4303	* @mgr: manager to use
2648	4304	* @pbn: payload bandwidth to convert into slots.
	4305	+ *
	4306	+ * Calculate the number of VCPI slots that will be required for the given PBN
	4307	+ * value. This function is deprecated, and should not be used in atomic
	4308	+ * drivers.
	4309	+ *
	4310	+ * RETURNS:
	4311	+ * The total slots required for this port, or error.
2649	4312	*/
2650	4313	int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
2651	4314	int pbn)
..	..	@@ -2681,42 +4344,100 @@
2681	4344	}
2682	4345
2683	4346	/**
2684		- * drm_dp_atomic_find_vcpi_slots() - Find and add vcpi slots to the state
	4347	+ * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
2685	4348	* @state: global atomic state
2686	4349	* @mgr: MST topology manager for the port
2687	4350	* @port: port to find vcpi slots for
2688	4351	* @pbn: bandwidth required for the mode in PBN
	4352	+ * @pbn_div: divider for DSC mode that takes FEC into account
2689	4353	*
2690		- * RETURNS:
2691		- * Total slots in the atomic state assigned for this port or error
	4354	+ * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
	4355	+ * may have had. Any atomic drivers which support MST must call this function
	4356	+ * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
	4357	+ * current VCPI allocation for the new state, but only when
	4358	+ * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
	4359	+ * to ensure compatibility with userspace applications that still use the
	4360	+ * legacy modesetting UAPI.
	4361	+ *
	4362	+ * Allocations set by this function are not checked against the bandwidth
	4363	+ * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
	4364	+ *
	4365	+ * Additionally, it is OK to call this function multiple times on the same
	4366	+ * @port as needed. It is not OK however, to call this function and
	4367	+ * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
	4368	+ *
	4369	+ * See also:
	4370	+ * drm_dp_atomic_release_vcpi_slots()
	4371	+ * drm_dp_mst_atomic_check()
	4372	+ *
	4373	+ * Returns:
	4374	+ * Total slots in the atomic state assigned for this port, or a negative error
	4375	+ * code if the port no longer exists
2692	4376	*/
2693	4377	int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
2694	4378	struct drm_dp_mst_topology_mgr *mgr,
2695		- struct drm_dp_mst_port *port, int pbn)
	4379	+ struct drm_dp_mst_port *port, int pbn,
	4380	+ int pbn_div)
2696	4381	{
2697	4382	struct drm_dp_mst_topology_state *topology_state;
2698		- int req_slots;
	4383	+ struct drm_dp_vcpi_allocation pos, vcpi = NULL;
	4384	+ int prev_slots, prev_bw, req_slots;
2699	4385
2700	4386	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
2701	4387	if (IS_ERR(topology_state))
2702	4388	return PTR_ERR(topology_state);
2703	4389
2704		- port = drm_dp_get_validated_port_ref(mgr, port);
2705		- if (port == NULL)
2706		- return -EINVAL;
2707		- req_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2708		- DRM_DEBUG_KMS("vcpi slots req=%d, avail=%d\n",
2709		- req_slots, topology_state->avail_slots);
	4390	+ /* Find the current allocation for this port, if any */
	4391	+ list_for_each_entry(pos, &topology_state->vcpis, next) {
	4392	+ if (pos->port == port) {
	4393	+ vcpi = pos;
	4394	+ prev_slots = vcpi->vcpi;
	4395	+ prev_bw = vcpi->pbn;
2710	4396
2711		- if (req_slots > topology_state->avail_slots) {
2712		- drm_dp_put_port(port);
2713		- return -ENOSPC;
	4397	+ /*
	4398	+ * This should never happen, unless the driver tries
	4399	+ * releasing and allocating the same VCPI allocation,
	4400	+ * which is an error
	4401	+ */
	4402	+ if (WARN_ON(!prev_slots)) {
	4403	+ DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
	4404	+ port);
	4405	+ return -EINVAL;
	4406	+ }
	4407	+
	4408	+ break;
	4409	+ }
	4410	+ }
	4411	+ if (!vcpi) {
	4412	+ prev_slots = 0;
	4413	+ prev_bw = 0;
2714	4414	}
2715	4415
2716		- topology_state->avail_slots -= req_slots;
2717		- DRM_DEBUG_KMS("vcpi slots avail=%d", topology_state->avail_slots);
	4416	+ if (pbn_div <= 0)
	4417	+ pbn_div = mgr->pbn_div;
2718	4418
2719		- drm_dp_put_port(port);
	4419	+ req_slots = DIV_ROUND_UP(pbn, pbn_div);
	4420	+
	4421	+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
	4422	+ port->connector->base.id, port->connector->name,
	4423	+ port, prev_slots, req_slots);
	4424	+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
	4425	+ port->connector->base.id, port->connector->name,
	4426	+ port, prev_bw, pbn);
	4427	+
	4428	+ /* Add the new allocation to the state */
	4429	+ if (!vcpi) {
	4430	+ vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
	4431	+ if (!vcpi)
	4432	+ return -ENOMEM;
	4433	+
	4434	+ drm_dp_mst_get_port_malloc(port);
	4435	+ vcpi->port = port;
	4436	+ list_add(&vcpi->next, &topology_state->vcpis);
	4437	+ }
	4438	+ vcpi->vcpi = req_slots;
	4439	+ vcpi->pbn = pbn;
	4440	+
2720	4441	return req_slots;
2721	4442	}
2722	4443	EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
..	..	@@ -2725,31 +4446,58 @@
2725	4446	* drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
2726	4447	* @state: global atomic state
2727	4448	* @mgr: MST topology manager for the port
2728		- * @slots: number of vcpi slots to release
	4449	+ * @port: The port to release the VCPI slots from
2729	4450	*
2730		- * RETURNS:
2731		- * 0 if @slots were added back to &drm_dp_mst_topology_state->avail_slots or
2732		- * negative error code
	4451	+ * Releases any VCPI slots that have been allocated to a port in the atomic
	4452	+ * state. Any atomic drivers which support MST must call this function in
	4453	+ * their &drm_connector_helper_funcs.atomic_check() callback when the
	4454	+ * connector will no longer have VCPI allocated (e.g. because its CRTC was
	4455	+ * removed) when it had VCPI allocated in the previous atomic state.
	4456	+ *
	4457	+ * It is OK to call this even if @port has been removed from the system.
	4458	+ * Additionally, it is OK to call this function multiple times on the same
	4459	+ * @port as needed. It is not OK however, to call this function and
	4460	+ * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
	4461	+ * phase.
	4462	+ *
	4463	+ * See also:
	4464	+ * drm_dp_atomic_find_vcpi_slots()
	4465	+ * drm_dp_mst_atomic_check()
	4466	+ *
	4467	+ * Returns:
	4468	+ * 0 if all slots for this port were added back to
	4469	+ * &drm_dp_mst_topology_state.avail_slots or negative error code
2733	4470	*/
2734	4471	int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
2735	4472	struct drm_dp_mst_topology_mgr *mgr,
2736		- int slots)
	4473	+ struct drm_dp_mst_port *port)
2737	4474	{
2738	4475	struct drm_dp_mst_topology_state *topology_state;
	4476	+ struct drm_dp_vcpi_allocation *pos;
	4477	+ bool found = false;
2739	4478
2740	4479	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
2741	4480	if (IS_ERR(topology_state))
2742	4481	return PTR_ERR(topology_state);
2743	4482
2744		- /* We cannot rely on port->vcpi.num_slots to update
2745		- * topology_state->avail_slots as the port may not exist if the parent
2746		- * branch device was unplugged. This should be fixed by tracking
2747		- * per-port slot allocation in drm_dp_mst_topology_state instead of
2748		- * depending on the caller to tell us how many slots to release.
2749		- */
2750		- topology_state->avail_slots += slots;
2751		- DRM_DEBUG_KMS("vcpi slots released=%d, avail=%d\n",
2752		- slots, topology_state->avail_slots);
	4483	+ list_for_each_entry(pos, &topology_state->vcpis, next) {
	4484	+ if (pos->port == port) {
	4485	+ found = true;
	4486	+ break;
	4487	+ }
	4488	+ }
	4489	+ if (WARN_ON(!found)) {
	4490	+ DRM_ERROR("no VCPI for [MST PORT:%p] found in mst state %p\n",
	4491	+ port, &topology_state->base);
	4492	+ return -EINVAL;
	4493	+ }
	4494	+
	4495	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
	4496	+ if (pos->vcpi) {
	4497	+ drm_dp_mst_put_port_malloc(port);
	4498	+ pos->vcpi = 0;
	4499	+ pos->pbn = 0;
	4500	+ }
2753	4501
2754	4502	return 0;
2755	4503	}
..	..	@@ -2770,14 +4518,15 @@
2770	4518	if (slots < 0)
2771	4519	return false;
2772	4520
2773		- port = drm_dp_get_validated_port_ref(mgr, port);
	4521	+ port = drm_dp_mst_topology_get_port_validated(mgr, port);
2774	4522	if (!port)
2775	4523	return false;
2776	4524
2777	4525	if (port->vcpi.vcpi > 0) {
2778		- DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
	4526	+ DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
	4527	+ port->vcpi.vcpi, port->vcpi.pbn, pbn);
2779	4528	if (pbn == port->vcpi.pbn) {
2780		- drm_dp_put_port(port);
	4529	+ drm_dp_mst_topology_put_port(port);
2781	4530	return true;
2782	4531	}
2783	4532	}
..	..	@@ -2785,14 +4534,16 @@
2785	4534	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
2786	4535	if (ret) {
2787	4536	DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
2788		- DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
2789		- drm_dp_put_port(port);
	4537	+ DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
	4538	+ drm_dp_mst_topology_put_port(port);
2790	4539	goto out;
2791	4540	}
2792	4541	DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
2793		- pbn, port->vcpi.num_slots);
	4542	+ pbn, port->vcpi.num_slots);
2794	4543
2795		- drm_dp_put_port(port);
	4544	+ /* Keep port allocated until its payload has been removed */
	4545	+ drm_dp_mst_get_port_malloc(port);
	4546	+ drm_dp_mst_topology_put_port(port);
2796	4547	return true;
2797	4548	out:
2798	4549	return false;
..	..	@@ -2802,12 +4553,13 @@
2802	4553	int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr mgr, struct drm_dp_mst_port port)
2803	4554	{
2804	4555	int slots = 0;
2805		- port = drm_dp_get_validated_port_ref(mgr, port);
	4556	+
	4557	+ port = drm_dp_mst_topology_get_port_validated(mgr, port);
2806	4558	if (!port)
2807	4559	return slots;
2808	4560
2809	4561	slots = port->vcpi.num_slots;
2810		- drm_dp_put_port(port);
	4562	+ drm_dp_mst_topology_put_port(port);
2811	4563	return slots;
2812	4564	}
2813	4565	EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
..	..	@@ -2821,23 +4573,36 @@
2821	4573	*/
2822	4574	void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr mgr, struct drm_dp_mst_port port)
2823	4575	{
2824		- port = drm_dp_get_validated_port_ref(mgr, port);
2825		- if (!port)
2826		- return;
	4576	+ /*
	4577	+ * A port with VCPI will remain allocated until its VCPI is
	4578	+ * released, no verified ref needed
	4579	+ */
	4580	+
2827	4581	port->vcpi.num_slots = 0;
2828		- drm_dp_put_port(port);
2829	4582	}
2830	4583	EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
2831	4584
2832	4585	/**
2833	4586	* drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
2834	4587	* @mgr: manager for this port
2835		- * @port: unverified port to deallocate vcpi for
	4588	+ * @port: port to deallocate vcpi for
	4589	+ *
	4590	+ * This can be called unconditionally, regardless of whether
	4591	+ * drm_dp_mst_allocate_vcpi() succeeded or not.
2836	4592	*/
2837		-void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr mgr, struct drm_dp_mst_port port)
	4593	+void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
	4594	+ struct drm_dp_mst_port *port)
2838	4595	{
2839		- port = drm_dp_get_validated_port_ref(mgr, port);
2840		- if (!port)
	4596	+ bool skip;
	4597	+
	4598	+ if (!port->vcpi.vcpi)
	4599	+ return;
	4600	+
	4601	+ mutex_lock(&mgr->lock);
	4602	+ skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
	4603	+ mutex_unlock(&mgr->lock);
	4604	+
	4605	+ if (skip)
2841	4606	return;
2842	4607
2843	4608	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
..	..	@@ -2845,7 +4610,7 @@
2845	4610	port->vcpi.pbn = 0;
2846	4611	port->vcpi.aligned_pbn = 0;
2847	4612	port->vcpi.vcpi = 0;
2848		- drm_dp_put_port(port);
	4613	+ drm_dp_mst_put_port_malloc(port);
2849	4614	}
2850	4615	EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
2851	4616
..	..	@@ -2904,10 +4669,15 @@
2904	4669	}
2905	4670
2906	4671	/**
2907		- * drm_dp_check_act_status() - Check ACT handled status.
	4672	+ * drm_dp_check_act_status() - Polls for ACT handled status.
2908	4673	* @mgr: manager to use
2909	4674	*
2910		- * Check the payload status bits in the DPCD for ACT handled completion.
	4675	+ * Tries waiting for the MST hub to finish updating it's payload table by
	4676	+ * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
	4677	+ * take that long).
	4678	+ *
	4679	+ * Returns:
	4680	+ * 0 if the ACT was handled in time, negative error code on failure.
2911	4681	*/
2912	4682	int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
2913	4683	{
..	..	@@ -2924,10 +4694,14 @@
2924	4694	status & DP_PAYLOAD_ACT_HANDLED \|\| status < 0,
2925	4695	200, timeout_ms * USEC_PER_MSEC);
2926	4696	if (ret < 0 && status >= 0) {
2927		- DRM_DEBUG_KMS("Failed to get ACT after %dms, last status: %02x\n",
2928		- timeout_ms, status);
	4697	+ DRM_ERROR("Failed to get ACT after %dms, last status: %02x\n",
	4698	+ timeout_ms, status);
2929	4699	return -EINVAL;
2930	4700	} else if (status < 0) {
	4701	+ /*
	4702	+ * Failure here isn't unexpected - the hub may have
	4703	+ * just been unplugged
	4704	+ */
2931	4705	DRM_DEBUG_KMS("Failed to read payload table status: %d\n",
2932	4706	status);
2933	4707	return status;
..	..	@@ -2941,18 +4715,12 @@
2941	4715	* drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
2942	4716	* @clock: dot clock for the mode
2943	4717	* @bpp: bpp for the mode.
	4718	+ * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
2944	4719	*
2945	4720	* This uses the formula in the spec to calculate the PBN value for a mode.
2946	4721	*/
2947		-int drm_dp_calc_pbn_mode(int clock, int bpp)
	4722	+int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
2948	4723	{
2949		- u64 kbps;
2950		- s64 peak_kbps;
2951		- u32 numerator;
2952		- u32 denominator;
2953		-
2954		- kbps = clock * bpp;
2955		-
2956	4724	/*
2957	4725	* margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
2958	4726	* The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
..	..	@@ -2962,41 +4730,20 @@
2962	4730	* peak_kbps *= (1006/1000)
2963	4731	* peak_kbps *= (64/54)
2964	4732	* peak_kbps *= 8 convert to bytes
	4733	+ *
	4734	+ * If the bpp is in units of 1/16, further divide by 16. Put this
	4735	+ * factor in the numerator rather than the denominator to avoid
	4736	+ * integer overflow
2965	4737	*/
2966	4738
2967		- numerator = 64 * 1006;
2968		- denominator = 54 * 8 * 1000 * 1000;
	4739	+ if (dsc)
	4740	+ return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
	4741	+ 8 * 54 * 1000 * 1000);
2969	4742
2970		- kbps *= numerator;
2971		- peak_kbps = drm_fixp_from_fraction(kbps, denominator);
2972		-
2973		- return drm_fixp2int_ceil(peak_kbps);
	4743	+ return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
	4744	+ 8 * 54 * 1000 * 1000);
2974	4745	}
2975	4746	EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
2976		-
2977		-static int test_calc_pbn_mode(void)
2978		-{
2979		- int ret;
2980		- ret = drm_dp_calc_pbn_mode(154000, 30);
2981		- if (ret != 689) {
2982		- DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2983		- 154000, 30, 689, ret);
2984		- return -EINVAL;
2985		- }
2986		- ret = drm_dp_calc_pbn_mode(234000, 30);
2987		- if (ret != 1047) {
2988		- DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2989		- 234000, 30, 1047, ret);
2990		- return -EINVAL;
2991		- }
2992		- ret = drm_dp_calc_pbn_mode(297000, 24);
2993		- if (ret != 1063) {
2994		- DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2995		- 297000, 24, 1063, ret);
2996		- return -EINVAL;
2997		- }
2998		- return 0;
2999		-}
3000	4747
3001	4748	/* we want to kick the TX after we've ack the up/down IRQs. */
3002	4749	static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
..	..	@@ -3048,6 +4795,7 @@
3048	4795
3049	4796	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
3050	4797	drm_edid_get_monitor_name(mst_edid, name, namelen);
	4798	+ kfree(mst_edid);
3051	4799	}
3052	4800
3053	4801	/**
..	..	@@ -3104,15 +4852,34 @@
3104	4852	int ret;
3105	4853
3106	4854	ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
	4855	+ if (ret) {
	4856	+ seq_printf(m, "dpcd read failed\n");
	4857	+ goto out;
	4858	+ }
3107	4859	seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
	4860	+
3108	4861	ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
	4862	+ if (ret != 2) {
	4863	+ seq_printf(m, "faux/mst read failed\n");
	4864	+ goto out;
	4865	+ }
3109	4866	seq_printf(m, "faux/mst: %*ph\n", 2, buf);
	4867	+
3110	4868	ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
	4869	+ if (ret != 1) {
	4870	+ seq_printf(m, "mst ctrl read failed\n");
	4871	+ goto out;
	4872	+ }
3111	4873	seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
3112	4874
3113	4875	/* dump the standard OUI branch header */
3114	4876	ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
	4877	+ if (ret != DP_BRANCH_OUI_HEADER_SIZE) {
	4878	+ seq_printf(m, "branch oui read failed\n");
	4879	+ goto out;
	4880	+ }
3115	4881	seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
	4882	+
3116	4883	for (i = 0x3; i < 0x8 && buf[i]; i++)
3117	4884	seq_printf(m, "%c", buf[i]);
3118	4885	seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
..	..	@@ -3121,6 +4888,7 @@
3121	4888	seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
3122	4889	}
3123	4890
	4891	+out:
3124	4892	mutex_unlock(&mgr->lock);
3125	4893
3126	4894	}
..	..	@@ -3136,66 +4904,147 @@
3136	4904	mutex_unlock(&mgr->qlock);
3137	4905	}
3138	4906
3139		-static void drm_dp_free_mst_port(struct kref *kref)
	4907	+static inline void
	4908	+drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
3140	4909	{
3141		- struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
3142		- kref_put(&port->parent->kref, drm_dp_free_mst_branch_device);
3143		- kfree(port);
	4910	+ drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
	4911	+
	4912	+ if (port->connector) {
	4913	+ drm_connector_unregister(port->connector);
	4914	+ drm_connector_put(port->connector);
	4915	+ }
	4916	+
	4917	+ drm_dp_mst_put_port_malloc(port);
3144	4918	}
3145	4919
3146		-static void drm_dp_destroy_connector_work(struct work_struct *work)
	4920	+static inline void
	4921	+drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
3147	4922	{
3148		- struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
3149		- struct drm_dp_mst_port *port;
3150		- bool send_hotplug = false;
	4923	+ struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
	4924	+ struct drm_dp_mst_port port, port_tmp;
	4925	+ struct drm_dp_sideband_msg_tx txmsg, txmsg_tmp;
	4926	+ bool wake_tx = false;
	4927	+
	4928	+ mutex_lock(&mgr->lock);
	4929	+ list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
	4930	+ list_del(&port->next);
	4931	+ drm_dp_mst_topology_put_port(port);
	4932	+ }
	4933	+ mutex_unlock(&mgr->lock);
	4934	+
	4935	+ /* drop any tx slot msg */
	4936	+ mutex_lock(&mstb->mgr->qlock);
	4937	+ list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
	4938	+ if (txmsg->dst != mstb)
	4939	+ continue;
	4940	+
	4941	+ txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
	4942	+ list_del(&txmsg->next);
	4943	+ wake_tx = true;
	4944	+ }
	4945	+ mutex_unlock(&mstb->mgr->qlock);
	4946	+
	4947	+ if (wake_tx)
	4948	+ wake_up_all(&mstb->mgr->tx_waitq);
	4949	+
	4950	+ drm_dp_mst_put_mstb_malloc(mstb);
	4951	+}
	4952	+
	4953	+static void drm_dp_delayed_destroy_work(struct work_struct *work)
	4954	+{
	4955	+ struct drm_dp_mst_topology_mgr *mgr =
	4956	+ container_of(work, struct drm_dp_mst_topology_mgr,
	4957	+ delayed_destroy_work);
	4958	+ bool send_hotplug = false, go_again;
	4959	+
3151	4960	/*
3152	4961	* Not a regular list traverse as we have to drop the destroy
3153		- * connector lock before destroying the connector, to avoid AB->BA
	4962	+ * connector lock before destroying the mstb/port, to avoid AB->BA
3154	4963	* ordering between this lock and the config mutex.
3155	4964	*/
3156		- for (;;) {
3157		- mutex_lock(&mgr->destroy_connector_lock);
3158		- port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
3159		- if (!port) {
3160		- mutex_unlock(&mgr->destroy_connector_lock);
3161		- break;
3162		- }
3163		- list_del(&port->next);
3164		- mutex_unlock(&mgr->destroy_connector_lock);
	4965	+ do {
	4966	+ go_again = false;
3165	4967
3166		- kref_init(&port->kref);
3167		- INIT_LIST_HEAD(&port->next);
	4968	+ for (;;) {
	4969	+ struct drm_dp_mst_branch *mstb;
3168	4970
3169		- mgr->cbs->destroy_connector(mgr, port->connector);
	4971	+ mutex_lock(&mgr->delayed_destroy_lock);
	4972	+ mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
	4973	+ struct drm_dp_mst_branch,
	4974	+ destroy_next);
	4975	+ if (mstb)
	4976	+ list_del(&mstb->destroy_next);
	4977	+ mutex_unlock(&mgr->delayed_destroy_lock);
3170	4978
3171		- drm_dp_port_teardown_pdt(port, port->pdt);
3172		- port->pdt = DP_PEER_DEVICE_NONE;
	4979	+ if (!mstb)
	4980	+ break;
3173	4981
3174		- if (!port->input && port->vcpi.vcpi > 0) {
3175		- drm_dp_mst_reset_vcpi_slots(mgr, port);
3176		- drm_dp_update_payload_part1(mgr);
3177		- drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
	4982	+ drm_dp_delayed_destroy_mstb(mstb);
	4983	+ go_again = true;
3178	4984	}
3179	4985
3180		- kref_put(&port->kref, drm_dp_free_mst_port);
3181		- send_hotplug = true;
3182		- }
	4986	+ for (;;) {
	4987	+ struct drm_dp_mst_port *port;
	4988	+
	4989	+ mutex_lock(&mgr->delayed_destroy_lock);
	4990	+ port = list_first_entry_or_null(&mgr->destroy_port_list,
	4991	+ struct drm_dp_mst_port,
	4992	+ next);
	4993	+ if (port)
	4994	+ list_del(&port->next);
	4995	+ mutex_unlock(&mgr->delayed_destroy_lock);
	4996	+
	4997	+ if (!port)
	4998	+ break;
	4999	+
	5000	+ drm_dp_delayed_destroy_port(port);
	5001	+ send_hotplug = true;
	5002	+ go_again = true;
	5003	+ }
	5004	+ } while (go_again);
	5005	+
3183	5006	if (send_hotplug)
3184		- (*mgr->cbs->hotplug)(mgr);
	5007	+ drm_kms_helper_hotplug_event(mgr->dev);
3185	5008	}
3186	5009
3187	5010	static struct drm_private_state *
3188	5011	drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
3189	5012	{
3190		- struct drm_dp_mst_topology_state *state;
	5013	+ struct drm_dp_mst_topology_state state, old_state =
	5014	+ to_dp_mst_topology_state(obj->state);
	5015	+ struct drm_dp_vcpi_allocation pos, vcpi;
3191	5016
3192		- state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
	5017	+ state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
3193	5018	if (!state)
3194	5019	return NULL;
3195	5020
3196	5021	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
3197	5022
	5023	+ INIT_LIST_HEAD(&state->vcpis);
	5024	+
	5025	+ list_for_each_entry(pos, &old_state->vcpis, next) {
	5026	+ /* Prune leftover freed VCPI allocations */
	5027	+ if (!pos->vcpi)
	5028	+ continue;
	5029	+
	5030	+ vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
	5031	+ if (!vcpi)
	5032	+ goto fail;
	5033	+
	5034	+ drm_dp_mst_get_port_malloc(vcpi->port);
	5035	+ list_add(&vcpi->next, &state->vcpis);
	5036	+ }
	5037	+
3198	5038	return &state->base;
	5039	+
	5040	+fail:
	5041	+ list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
	5042	+ drm_dp_mst_put_port_malloc(pos->port);
	5043	+ kfree(pos);
	5044	+ }
	5045	+ kfree(state);
	5046	+
	5047	+ return NULL;
3199	5048	}
3200	5049
3201	5050	static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
..	..	@@ -3203,14 +5052,346 @@
3203	5052	{
3204	5053	struct drm_dp_mst_topology_state *mst_state =
3205	5054	to_dp_mst_topology_state(state);
	5055	+ struct drm_dp_vcpi_allocation pos, tmp;
	5056	+
	5057	+ list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
	5058	+ /* We only keep references to ports with non-zero VCPIs */
	5059	+ if (pos->vcpi)
	5060	+ drm_dp_mst_put_port_malloc(pos->port);
	5061	+ kfree(pos);
	5062	+ }
3206	5063
3207	5064	kfree(mst_state);
3208	5065	}
3209	5066
3210		-static const struct drm_private_state_funcs mst_state_funcs = {
	5067	+static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
	5068	+ struct drm_dp_mst_branch *branch)
	5069	+{
	5070	+ while (port->parent) {
	5071	+ if (port->parent == branch)
	5072	+ return true;
	5073	+
	5074	+ if (port->parent->port_parent)
	5075	+ port = port->parent->port_parent;
	5076	+ else
	5077	+ break;
	5078	+ }
	5079	+ return false;
	5080	+}
	5081	+
	5082	+static int
	5083	+drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
	5084	+ struct drm_dp_mst_topology_state *state);
	5085	+
	5086	+static int
	5087	+drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
	5088	+ struct drm_dp_mst_topology_state *state)
	5089	+{
	5090	+ struct drm_dp_vcpi_allocation *vcpi;
	5091	+ struct drm_dp_mst_port *port;
	5092	+ int pbn_used = 0, ret;
	5093	+ bool found = false;
	5094	+
	5095	+ /* Check that we have at least one port in our state that's downstream
	5096	+ * of this branch, otherwise we can skip this branch
	5097	+ */
	5098	+ list_for_each_entry(vcpi, &state->vcpis, next) {
	5099	+ if (!vcpi->pbn \|\|
	5100	+ !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
	5101	+ continue;
	5102	+
	5103	+ found = true;
	5104	+ break;
	5105	+ }
	5106	+ if (!found)
	5107	+ return 0;
	5108	+
	5109	+ if (mstb->port_parent)
	5110	+ DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
	5111	+ mstb->port_parent->parent, mstb->port_parent,
	5112	+ mstb);
	5113	+ else
	5114	+ DRM_DEBUG_ATOMIC("[MSTB:%p] Checking bandwidth limits\n",
	5115	+ mstb);
	5116	+
	5117	+ list_for_each_entry(port, &mstb->ports, next) {
	5118	+ ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
	5119	+ if (ret < 0)
	5120	+ return ret;
	5121	+
	5122	+ pbn_used += ret;
	5123	+ }
	5124	+
	5125	+ return pbn_used;
	5126	+}
	5127	+
	5128	+static int
	5129	+drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
	5130	+ struct drm_dp_mst_topology_state *state)
	5131	+{
	5132	+ struct drm_dp_vcpi_allocation *vcpi;
	5133	+ int pbn_used = 0;
	5134	+
	5135	+ if (port->pdt == DP_PEER_DEVICE_NONE)
	5136	+ return 0;
	5137	+
	5138	+ if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
	5139	+ bool found = false;
	5140	+
	5141	+ list_for_each_entry(vcpi, &state->vcpis, next) {
	5142	+ if (vcpi->port != port)
	5143	+ continue;
	5144	+ if (!vcpi->pbn)
	5145	+ return 0;
	5146	+
	5147	+ found = true;
	5148	+ break;
	5149	+ }
	5150	+ if (!found)
	5151	+ return 0;
	5152	+
	5153	+ /* This should never happen, as it means we tried to
	5154	+ * set a mode before querying the full_pbn
	5155	+ */
	5156	+ if (WARN_ON(!port->full_pbn))
	5157	+ return -EINVAL;
	5158	+
	5159	+ pbn_used = vcpi->pbn;
	5160	+ } else {
	5161	+ pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
	5162	+ state);
	5163	+ if (pbn_used <= 0)
	5164	+ return pbn_used;
	5165	+ }
	5166	+
	5167	+ if (pbn_used > port->full_pbn) {
	5168	+ DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
	5169	+ port->parent, port, pbn_used,
	5170	+ port->full_pbn);
	5171	+ return -ENOSPC;
	5172	+ }
	5173	+
	5174	+ DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
	5175	+ port->parent, port, pbn_used, port->full_pbn);
	5176	+
	5177	+ return pbn_used;
	5178	+}
	5179	+
	5180	+static inline int
	5181	+drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
	5182	+ struct drm_dp_mst_topology_state *mst_state)
	5183	+{
	5184	+ struct drm_dp_vcpi_allocation *vcpi;
	5185	+ int avail_slots = 63, payload_count = 0;
	5186	+
	5187	+ list_for_each_entry(vcpi, &mst_state->vcpis, next) {
	5188	+ /* Releasing VCPI is always OK-even if the port is gone */
	5189	+ if (!vcpi->vcpi) {
	5190	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] releases all VCPI slots\n",
	5191	+ vcpi->port);
	5192	+ continue;
	5193	+ }
	5194	+
	5195	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] requires %d vcpi slots\n",
	5196	+ vcpi->port, vcpi->vcpi);
	5197	+
	5198	+ avail_slots -= vcpi->vcpi;
	5199	+ if (avail_slots < 0) {
	5200	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
	5201	+ vcpi->port, mst_state,
	5202	+ avail_slots + vcpi->vcpi);
	5203	+ return -ENOSPC;
	5204	+ }
	5205	+
	5206	+ if (++payload_count > mgr->max_payloads) {
	5207	+ DRM_DEBUG_ATOMIC("[MST MGR:%p] state %p has too many payloads (max=%d)\n",
	5208	+ mgr, mst_state, mgr->max_payloads);
	5209	+ return -EINVAL;
	5210	+ }
	5211	+ }
	5212	+ DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
	5213	+ mgr, mst_state, avail_slots,
	5214	+ 63 - avail_slots);
	5215	+
	5216	+ return 0;
	5217	+}
	5218	+
	5219	+/**
	5220	+ * drm_dp_mst_add_affected_dsc_crtcs
	5221	+ * @state: Pointer to the new struct drm_dp_mst_topology_state
	5222	+ * @mgr: MST topology manager
	5223	+ *
	5224	+ * Whenever there is a change in mst topology
	5225	+ * DSC configuration would have to be recalculated
	5226	+ * therefore we need to trigger modeset on all affected
	5227	+ * CRTCs in that topology
	5228	+ *
	5229	+ * See also:
	5230	+ * drm_dp_mst_atomic_enable_dsc()
	5231	+ */
	5232	+int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state state, struct drm_dp_mst_topology_mgr mgr)
	5233	+{
	5234	+ struct drm_dp_mst_topology_state *mst_state;
	5235	+ struct drm_dp_vcpi_allocation *pos;
	5236	+ struct drm_connector *connector;
	5237	+ struct drm_connector_state *conn_state;
	5238	+ struct drm_crtc *crtc;
	5239	+ struct drm_crtc_state *crtc_state;
	5240	+
	5241	+ mst_state = drm_atomic_get_mst_topology_state(state, mgr);
	5242	+
	5243	+ if (IS_ERR(mst_state))
	5244	+ return PTR_ERR(mst_state);
	5245	+
	5246	+ list_for_each_entry(pos, &mst_state->vcpis, next) {
	5247	+
	5248	+ connector = pos->port->connector;
	5249	+
	5250	+ if (!connector)
	5251	+ return -EINVAL;
	5252	+
	5253	+ conn_state = drm_atomic_get_connector_state(state, connector);
	5254	+
	5255	+ if (IS_ERR(conn_state))
	5256	+ return PTR_ERR(conn_state);
	5257	+
	5258	+ crtc = conn_state->crtc;
	5259	+
	5260	+ if (!crtc)
	5261	+ continue;
	5262	+
	5263	+ if (!drm_dp_mst_dsc_aux_for_port(pos->port))
	5264	+ continue;
	5265	+
	5266	+ crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
	5267	+
	5268	+ if (IS_ERR(crtc_state))
	5269	+ return PTR_ERR(crtc_state);
	5270	+
	5271	+ DRM_DEBUG_ATOMIC("[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
	5272	+ mgr, crtc);
	5273	+
	5274	+ crtc_state->mode_changed = true;
	5275	+ }
	5276	+ return 0;
	5277	+}
	5278	+EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
	5279	+
	5280	+/**
	5281	+ * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
	5282	+ * @state: Pointer to the new drm_atomic_state
	5283	+ * @port: Pointer to the affected MST Port
	5284	+ * @pbn: Newly recalculated bw required for link with DSC enabled
	5285	+ * @pbn_div: Divider to calculate correct number of pbn per slot
	5286	+ * @enable: Boolean flag to enable or disable DSC on the port
	5287	+ *
	5288	+ * This function enables DSC on the given Port
	5289	+ * by recalculating its vcpi from pbn provided
	5290	+ * and sets dsc_enable flag to keep track of which
	5291	+ * ports have DSC enabled
	5292	+ *
	5293	+ */
	5294	+int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
	5295	+ struct drm_dp_mst_port *port,
	5296	+ int pbn, int pbn_div,
	5297	+ bool enable)
	5298	+{
	5299	+ struct drm_dp_mst_topology_state *mst_state;
	5300	+ struct drm_dp_vcpi_allocation *pos;
	5301	+ bool found = false;
	5302	+ int vcpi = 0;
	5303	+
	5304	+ mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
	5305	+
	5306	+ if (IS_ERR(mst_state))
	5307	+ return PTR_ERR(mst_state);
	5308	+
	5309	+ list_for_each_entry(pos, &mst_state->vcpis, next) {
	5310	+ if (pos->port == port) {
	5311	+ found = true;
	5312	+ break;
	5313	+ }
	5314	+ }
	5315	+
	5316	+ if (!found) {
	5317	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
	5318	+ port, mst_state);
	5319	+ return -EINVAL;
	5320	+ }
	5321	+
	5322	+ if (pos->dsc_enabled == enable) {
	5323	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
	5324	+ port, enable, pos->vcpi);
	5325	+ vcpi = pos->vcpi;
	5326	+ }
	5327	+
	5328	+ if (enable) {
	5329	+ vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
	5330	+ DRM_DEBUG_ATOMIC("[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
	5331	+ port, vcpi);
	5332	+ if (vcpi < 0)
	5333	+ return -EINVAL;
	5334	+ }
	5335	+
	5336	+ pos->dsc_enabled = enable;
	5337	+
	5338	+ return vcpi;
	5339	+}
	5340	+EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
	5341	+/**
	5342	+ * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
	5343	+ * atomic update is valid
	5344	+ * @state: Pointer to the new &struct drm_dp_mst_topology_state
	5345	+ *
	5346	+ * Checks the given topology state for an atomic update to ensure that it's
	5347	+ * valid. This includes checking whether there's enough bandwidth to support
	5348	+ * the new VCPI allocations in the atomic update.
	5349	+ *
	5350	+ * Any atomic drivers supporting DP MST must make sure to call this after
	5351	+ * checking the rest of their state in their
	5352	+ * &drm_mode_config_funcs.atomic_check() callback.
	5353	+ *
	5354	+ * See also:
	5355	+ * drm_dp_atomic_find_vcpi_slots()
	5356	+ * drm_dp_atomic_release_vcpi_slots()
	5357	+ *
	5358	+ * Returns:
	5359	+ *
	5360	+ * 0 if the new state is valid, negative error code otherwise.
	5361	+ */
	5362	+int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
	5363	+{
	5364	+ struct drm_dp_mst_topology_mgr *mgr;
	5365	+ struct drm_dp_mst_topology_state *mst_state;
	5366	+ int i, ret = 0;
	5367	+
	5368	+ for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
	5369	+ if (!mgr->mst_state)
	5370	+ continue;
	5371	+
	5372	+ ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
	5373	+ if (ret)
	5374	+ break;
	5375	+
	5376	+ mutex_lock(&mgr->lock);
	5377	+ ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
	5378	+ mst_state);
	5379	+ mutex_unlock(&mgr->lock);
	5380	+ if (ret < 0)
	5381	+ break;
	5382	+ else
	5383	+ ret = 0;
	5384	+ }
	5385	+
	5386	+ return ret;
	5387	+}
	5388	+EXPORT_SYMBOL(drm_dp_mst_atomic_check);
	5389	+
	5390	+const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
3211	5391	.atomic_duplicate_state = drm_dp_mst_duplicate_state,
3212	5392	.atomic_destroy_state = drm_dp_mst_destroy_state,
3213	5393	};
	5394	+EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
3214	5395
3215	5396	/**
3216	5397	* drm_atomic_get_mst_topology_state: get MST topology state
..	..	@@ -3230,9 +5411,6 @@
3230	5411	struct drm_dp_mst_topology_state drm_atomic_get_mst_topology_state(struct drm_atomic_state state,
3231	5412	struct drm_dp_mst_topology_mgr *mgr)
3232	5413	{
3233		- struct drm_device *dev = mgr->dev;
3234		-
3235		- WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
3236	5414	return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
3237	5415	}
3238	5416	EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
..	..	@@ -3258,12 +5436,29 @@
3258	5436	mutex_init(&mgr->lock);
3259	5437	mutex_init(&mgr->qlock);
3260	5438	mutex_init(&mgr->payload_lock);
3261		- mutex_init(&mgr->destroy_connector_lock);
	5439	+ mutex_init(&mgr->delayed_destroy_lock);
	5440	+ mutex_init(&mgr->up_req_lock);
	5441	+ mutex_init(&mgr->probe_lock);
	5442	+#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	5443	+ mutex_init(&mgr->topology_ref_history_lock);
	5444	+#endif
3262	5445	INIT_LIST_HEAD(&mgr->tx_msg_downq);
3263		- INIT_LIST_HEAD(&mgr->destroy_connector_list);
	5446	+ INIT_LIST_HEAD(&mgr->destroy_port_list);
	5447	+ INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
	5448	+ INIT_LIST_HEAD(&mgr->up_req_list);
	5449	+
	5450	+ /*
	5451	+ * delayed_destroy_work will be queued on a dedicated WQ, so that any
	5452	+ * requeuing will be also flushed when deiniting the topology manager.
	5453	+ */
	5454	+ mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
	5455	+ if (mgr->delayed_destroy_wq == NULL)
	5456	+ return -ENOMEM;
	5457	+
3264	5458	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
3265	5459	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
3266		- INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
	5460	+ INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
	5461	+ INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
3267	5462	init_waitqueue_head(&mgr->tx_waitq);
3268	5463	mgr->dev = dev;
3269	5464	mgr->aux = aux;
..	..	@@ -3280,21 +5475,17 @@
3280	5475	if (!mgr->proposed_vcpis)
3281	5476	return -ENOMEM;
3282	5477	set_bit(0, &mgr->payload_mask);
3283		- if (test_calc_pbn_mode() < 0)
3284		- DRM_ERROR("MST PBN self-test failed\n");
3285	5478
3286	5479	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
3287	5480	if (mst_state == NULL)
3288	5481	return -ENOMEM;
3289	5482
3290	5483	mst_state->mgr = mgr;
	5484	+ INIT_LIST_HEAD(&mst_state->vcpis);
3291	5485
3292		- /* max. time slots - one slot for MTP header */
3293		- mst_state->avail_slots = 63;
3294		-
3295		- drm_atomic_private_obj_init(&mgr->base,
	5486	+ drm_atomic_private_obj_init(dev, &mgr->base,
3296	5487	&mst_state->base,
3297		- &mst_state_funcs);
	5488	+ &drm_dp_mst_topology_state_funcs);
3298	5489
3299	5490	return 0;
3300	5491	}
..	..	@@ -3306,8 +5497,13 @@
3306	5497	*/
3307	5498	void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
3308	5499	{
	5500	+ drm_dp_mst_topology_mgr_set_mst(mgr, false);
3309	5501	flush_work(&mgr->work);
3310		- flush_work(&mgr->destroy_connector_work);
	5502	+ /* The following will also drain any requeued work on the WQ. */
	5503	+ if (mgr->delayed_destroy_wq) {
	5504	+ destroy_workqueue(mgr->delayed_destroy_wq);
	5505	+ mgr->delayed_destroy_wq = NULL;
	5506	+ }
3311	5507	mutex_lock(&mgr->payload_lock);
3312	5508	kfree(mgr->payloads);
3313	5509	mgr->payloads = NULL;
..	..	@@ -3318,37 +5514,58 @@
3318	5514	mgr->aux = NULL;
3319	5515	drm_atomic_private_obj_fini(&mgr->base);
3320	5516	mgr->funcs = NULL;
	5517	+
	5518	+ mutex_destroy(&mgr->delayed_destroy_lock);
	5519	+ mutex_destroy(&mgr->payload_lock);
	5520	+ mutex_destroy(&mgr->qlock);
	5521	+ mutex_destroy(&mgr->lock);
	5522	+ mutex_destroy(&mgr->up_req_lock);
	5523	+ mutex_destroy(&mgr->probe_lock);
	5524	+#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	5525	+ mutex_destroy(&mgr->topology_ref_history_lock);
	5526	+#endif
3321	5527	}
3322	5528	EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
3323	5529
3324		-/* I2C device */
3325		-static int drm_dp_mst_i2c_xfer(struct i2c_adapter adapter, struct i2c_msg msgs,
3326		- int num)
	5530	+static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
3327	5531	{
3328		- struct drm_dp_aux *aux = adapter->algo_data;
3329		- struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
3330		- struct drm_dp_mst_branch *mstb;
	5532	+ int i;
	5533	+
	5534	+ if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
	5535	+ return false;
	5536	+
	5537	+ for (i = 0; i < num - 1; i++) {
	5538	+ if (msgs[i].flags & I2C_M_RD \|\|
	5539	+ msgs[i].len > 0xff)
	5540	+ return false;
	5541	+ }
	5542	+
	5543	+ return msgs[num - 1].flags & I2C_M_RD &&
	5544	+ msgs[num - 1].len <= 0xff;
	5545	+}
	5546	+
	5547	+static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
	5548	+{
	5549	+ int i;
	5550	+
	5551	+ for (i = 0; i < num - 1; i++) {
	5552	+ if (msgs[i].flags & I2C_M_RD \|\| !(msgs[i].flags & I2C_M_STOP) \|\|
	5553	+ msgs[i].len > 0xff)
	5554	+ return false;
	5555	+ }
	5556	+
	5557	+ return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
	5558	+}
	5559	+
	5560	+static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
	5561	+ struct drm_dp_mst_port *port,
	5562	+ struct i2c_msg *msgs, int num)
	5563	+{
3331	5564	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
3332	5565	unsigned int i;
3333		- bool reading = false;
3334	5566	struct drm_dp_sideband_msg_req_body msg;
3335	5567	struct drm_dp_sideband_msg_tx *txmsg = NULL;
3336	5568	int ret;
3337		-
3338		- mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
3339		- if (!mstb)
3340		- return -EREMOTEIO;
3341		-
3342		- /* construct i2c msg */
3343		- /* see if last msg is a read */
3344		- if (msgs[num - 1].flags & I2C_M_RD)
3345		- reading = true;
3346		-
3347		- if (!reading \|\| (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) {
3348		- DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
3349		- ret = -EIO;
3350		- goto out;
3351		- }
3352	5569
3353	5570	memset(&msg, 0, sizeof(msg));
3354	5571	msg.req_type = DP_REMOTE_I2C_READ;
..	..	@@ -3377,7 +5594,7 @@
3377	5594	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3378	5595	if (ret > 0) {
3379	5596
3380		- if (txmsg->reply.reply_type == 1) { /* got a NAK back */
	5597	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3381	5598	ret = -EREMOTEIO;
3382	5599	goto out;
3383	5600	}
..	..	@@ -3390,7 +5607,79 @@
3390	5607	}
3391	5608	out:
3392	5609	kfree(txmsg);
3393		- drm_dp_put_mst_branch_device(mstb);
	5610	+ return ret;
	5611	+}
	5612	+
	5613	+static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
	5614	+ struct drm_dp_mst_port *port,
	5615	+ struct i2c_msg *msgs, int num)
	5616	+{
	5617	+ struct drm_dp_mst_topology_mgr *mgr = port->mgr;
	5618	+ unsigned int i;
	5619	+ struct drm_dp_sideband_msg_req_body msg;
	5620	+ struct drm_dp_sideband_msg_tx *txmsg = NULL;
	5621	+ int ret;
	5622	+
	5623	+ txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
	5624	+ if (!txmsg) {
	5625	+ ret = -ENOMEM;
	5626	+ goto out;
	5627	+ }
	5628	+ for (i = 0; i < num; i++) {
	5629	+ memset(&msg, 0, sizeof(msg));
	5630	+ msg.req_type = DP_REMOTE_I2C_WRITE;
	5631	+ msg.u.i2c_write.port_number = port->port_num;
	5632	+ msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
	5633	+ msg.u.i2c_write.num_bytes = msgs[i].len;
	5634	+ msg.u.i2c_write.bytes = msgs[i].buf;
	5635	+
	5636	+ memset(txmsg, 0, sizeof(*txmsg));
	5637	+ txmsg->dst = mstb;
	5638	+
	5639	+ drm_dp_encode_sideband_req(&msg, txmsg);
	5640	+ drm_dp_queue_down_tx(mgr, txmsg);
	5641	+
	5642	+ ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
	5643	+ if (ret > 0) {
	5644	+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
	5645	+ ret = -EREMOTEIO;
	5646	+ goto out;
	5647	+ }
	5648	+ } else {
	5649	+ goto out;
	5650	+ }
	5651	+ }
	5652	+ ret = num;
	5653	+out:
	5654	+ kfree(txmsg);
	5655	+ return ret;
	5656	+}
	5657	+
	5658	+/* I2C device */
	5659	+static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
	5660	+ struct i2c_msg *msgs, int num)
	5661	+{
	5662	+ struct drm_dp_aux *aux = adapter->algo_data;
	5663	+ struct drm_dp_mst_port *port =
	5664	+ container_of(aux, struct drm_dp_mst_port, aux);
	5665	+ struct drm_dp_mst_branch *mstb;
	5666	+ struct drm_dp_mst_topology_mgr *mgr = port->mgr;
	5667	+ int ret;
	5668	+
	5669	+ mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
	5670	+ if (!mstb)
	5671	+ return -EREMOTEIO;
	5672	+
	5673	+ if (remote_i2c_read_ok(msgs, num)) {
	5674	+ ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
	5675	+ } else if (remote_i2c_write_ok(msgs, num)) {
	5676	+ ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
	5677	+ } else {
	5678	+ DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
	5679	+ ret = -EIO;
	5680	+ }
	5681	+
	5682	+ drm_dp_mst_topology_put_mstb(mstb);
3394	5683	return ret;
3395	5684	}
3396	5685
..	..	@@ -3409,22 +5698,26 @@
3409	5698
3410	5699	/**
3411	5700	* drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
3412		- * @aux: DisplayPort AUX channel
	5701	+ * @port: The port to add the I2C bus on
3413	5702	*
3414	5703	* Returns 0 on success or a negative error code on failure.
3415	5704	*/
3416		-static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
	5705	+static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
3417	5706	{
	5707	+ struct drm_dp_aux *aux = &port->aux;
	5708	+ struct device *parent_dev = port->mgr->dev->dev;
	5709	+
3418	5710	aux->ddc.algo = &drm_dp_mst_i2c_algo;
3419	5711	aux->ddc.algo_data = aux;
3420	5712	aux->ddc.retries = 3;
3421	5713
3422	5714	aux->ddc.class = I2C_CLASS_DDC;
3423	5715	aux->ddc.owner = THIS_MODULE;
3424		- aux->ddc.dev.parent = aux->dev;
3425		- aux->ddc.dev.of_node = aux->dev->of_node;
	5716	+ /* FIXME: set the kdev of the port's connector as parent */
	5717	+ aux->ddc.dev.parent = parent_dev;
	5718	+ aux->ddc.dev.of_node = parent_dev->of_node;
3426	5719
3427		- strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
	5720	+ strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
3428	5721	sizeof(aux->ddc.name));
3429	5722
3430	5723	return i2c_add_adapter(&aux->ddc);
..	..	@@ -3432,9 +5725,180 @@
3432	5725
3433	5726	/**
3434	5727	* drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
3435		- * @aux: DisplayPort AUX channel
	5728	+ * @port: The port to remove the I2C bus from
3436	5729	*/
3437		-static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
	5730	+static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
3438	5731	{
3439		- i2c_del_adapter(&aux->ddc);
	5732	+ i2c_del_adapter(&port->aux.ddc);
3440	5733	}
	5734	+
	5735	+/**
	5736	+ * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
	5737	+ * @port: The port to check
	5738	+ *
	5739	+ * A single physical MST hub object can be represented in the topology
	5740	+ * by multiple branches, with virtual ports between those branches.
	5741	+ *
	5742	+ * As of DP1.4, An MST hub with internal (virtual) ports must expose
	5743	+ * certain DPCD registers over those ports. See sections 2.6.1.1.1
	5744	+ * and 2.6.1.1.2 of Display Port specification v1.4 for details.
	5745	+ *
	5746	+ * May acquire mgr->lock
	5747	+ *
	5748	+ * Returns:
	5749	+ * true if the port is a virtual DP peer device, false otherwise
	5750	+ */
	5751	+static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
	5752	+{
	5753	+ struct drm_dp_mst_port *downstream_port;
	5754	+
	5755	+ if (!port \|\| port->dpcd_rev < DP_DPCD_REV_14)
	5756	+ return false;
	5757	+
	5758	+ /* Virtual DP Sink (Internal Display Panel) */
	5759	+ if (port->port_num >= 8)
	5760	+ return true;
	5761	+
	5762	+ /* DP-to-HDMI Protocol Converter */
	5763	+ if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
	5764	+ !port->mcs &&
	5765	+ port->ldps)
	5766	+ return true;
	5767	+
	5768	+ /* DP-to-DP */
	5769	+ mutex_lock(&port->mgr->lock);
	5770	+ if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
	5771	+ port->mstb &&
	5772	+ port->mstb->num_ports == 2) {
	5773	+ list_for_each_entry(downstream_port, &port->mstb->ports, next) {
	5774	+ if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
	5775	+ !downstream_port->input) {
	5776	+ mutex_unlock(&port->mgr->lock);
	5777	+ return true;
	5778	+ }
	5779	+ }
	5780	+ }
	5781	+ mutex_unlock(&port->mgr->lock);
	5782	+
	5783	+ return false;
	5784	+}
	5785	+
	5786	+/**
	5787	+ * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
	5788	+ * @port: The port to check. A leaf of the MST tree with an attached display.
	5789	+ *
	5790	+ * Depending on the situation, DSC may be enabled via the endpoint aux,
	5791	+ * the immediately upstream aux, or the connector's physical aux.
	5792	+ *
	5793	+ * This is both the correct aux to read DSC_CAPABILITY and the
	5794	+ * correct aux to write DSC_ENABLED.
	5795	+ *
	5796	+ * This operation can be expensive (up to four aux reads), so
	5797	+ * the caller should cache the return.
	5798	+ *
	5799	+ * Returns:
	5800	+ * NULL if DSC cannot be enabled on this port, otherwise the aux device
	5801	+ */
	5802	+struct drm_dp_aux drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port port)
	5803	+{
	5804	+ struct drm_dp_mst_port *immediate_upstream_port;
	5805	+ struct drm_dp_mst_port *fec_port;
	5806	+ struct drm_dp_desc desc = {};
	5807	+ u8 endpoint_fec;
	5808	+ u8 endpoint_dsc;
	5809	+
	5810	+ if (!port)
	5811	+ return NULL;
	5812	+
	5813	+ if (port->parent->port_parent)
	5814	+ immediate_upstream_port = port->parent->port_parent;
	5815	+ else
	5816	+ immediate_upstream_port = NULL;
	5817	+
	5818	+ fec_port = immediate_upstream_port;
	5819	+ while (fec_port) {
	5820	+ /*
	5821	+ * Each physical link (i.e. not a virtual port) between the
	5822	+ * output and the primary device must support FEC
	5823	+ */
	5824	+ if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
	5825	+ !fec_port->fec_capable)
	5826	+ return NULL;
	5827	+
	5828	+ fec_port = fec_port->parent->port_parent;
	5829	+ }
	5830	+
	5831	+ /* DP-to-DP peer device */
	5832	+ if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
	5833	+ u8 upstream_dsc;
	5834	+
	5835	+ if (drm_dp_dpcd_read(&port->aux,
	5836	+ DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
	5837	+ return NULL;
	5838	+ if (drm_dp_dpcd_read(&port->aux,
	5839	+ DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
	5840	+ return NULL;
	5841	+ if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
	5842	+ DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
	5843	+ return NULL;
	5844	+
	5845	+ /* Enpoint decompression with DP-to-DP peer device */
	5846	+ if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
	5847	+ (endpoint_fec & DP_FEC_CAPABLE) &&
	5848	+ (upstream_dsc & 0x2) /* DSC passthrough */)
	5849	+ return &port->aux;
	5850	+
	5851	+ /* Virtual DPCD decompression with DP-to-DP peer device */
	5852	+ return &immediate_upstream_port->aux;
	5853	+ }
	5854	+
	5855	+ /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
	5856	+ if (drm_dp_mst_is_virtual_dpcd(port))
	5857	+ return &port->aux;
	5858	+
	5859	+ /*
	5860	+ * Synaptics quirk
	5861	+ * Applies to ports for which:
	5862	+ * - Physical aux has Synaptics OUI
	5863	+ * - DPv1.4 or higher
	5864	+ * - Port is on primary branch device
	5865	+ * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
	5866	+ */
	5867	+ if (drm_dp_read_desc(port->mgr->aux, &desc, true))
	5868	+ return NULL;
	5869	+
	5870	+ if (drm_dp_has_quirk(&desc, 0,
	5871	+ DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
	5872	+ port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
	5873	+ port->parent == port->mgr->mst_primary) {
	5874	+ u8 downstreamport;
	5875	+
	5876	+ if (drm_dp_dpcd_read(&port->aux, DP_DOWNSTREAMPORT_PRESENT,
	5877	+ &downstreamport, 1) < 0)
	5878	+ return NULL;
	5879	+
	5880	+ if ((downstreamport & DP_DWN_STRM_PORT_PRESENT) &&
	5881	+ ((downstreamport & DP_DWN_STRM_PORT_TYPE_MASK)
	5882	+ != DP_DWN_STRM_PORT_TYPE_ANALOG))
	5883	+ return port->mgr->aux;
	5884	+ }
	5885	+
	5886	+ /*
	5887	+ * The check below verifies if the MST sink
	5888	+ * connected to the GPU is capable of DSC -
	5889	+ * therefore the endpoint needs to be
	5890	+ * both DSC and FEC capable.
	5891	+ */
	5892	+ if (drm_dp_dpcd_read(&port->aux,
	5893	+ DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
	5894	+ return NULL;
	5895	+ if (drm_dp_dpcd_read(&port->aux,
	5896	+ DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
	5897	+ return NULL;
	5898	+ if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
	5899	+ (endpoint_fec & DP_FEC_CAPABLE))
	5900	+ return &port->aux;
	5901	+
	5902	+ return NULL;
	5903	+}
	5904	+EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);