From 95099d4622f8cb224d94e314c7a8e0df60b13f87 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 08:38:01 +0000
Subject: [PATCH] enable docker ppp

---
 kernel/drivers/firmware/arm_scmi/driver.c | 1080 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 954 insertions(+), 126 deletions(-)

diff --git a/kernel/drivers/firmware/arm_scmi/driver.c b/kernel/drivers/firmware/arm_scmi/driver.c
index 34ad477..babadc7 100644
--- a/kernel/drivers/firmware/arm_scmi/driver.c
+++ b/kernel/drivers/firmware/arm_scmi/driver.c
@@ -11,24 +11,31 @@
  * various power domain DVFS including the core/cluster, certain system
  * clocks configuration, thermal sensors and many others.
  *
- * Copyright (C) 2018 ARM Ltd.
+ * Copyright (C) 2018-2020 ARM Ltd.
  */
 
 #include <linux/bitmap.h>
+#include <linux/device.h>
 #include <linux/export.h>
+#include <linux/idr.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/ktime.h>
+#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/processor.h>
+#include <linux/refcount.h>
 #include <linux/slab.h>
 
 #include "common.h"
+#include "notify.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/scmi.h>
+#undef CREATE_TRACE_POINTS
+#include <trace/hooks/scmi.h>
 
 enum scmi_error_codes {
 	SCMI_SUCCESS = 0,	/* Success */
@@ -51,6 +58,14 @@
 /* Track the unique id for the transfers for debug & profiling purpose */
 static atomic_t transfer_last_id;
 
+static DEFINE_IDR(scmi_requested_devices);
+static DEFINE_MUTEX(scmi_requested_devices_mtx);
+
+struct scmi_requested_dev {
+	const struct scmi_device_id *id_table;
+	struct list_head node;
+};
+
 /**
  * struct scmi_xfers_info - Structure to manage transfer information
  *
@@ -67,6 +82,30 @@
 };
 
 /**
+ * struct scmi_protocol_instance  - Describe an initialized protocol instance.
+ * @handle: Reference to the SCMI handle associated to this protocol instance.
+ * @proto: A reference to the protocol descriptor.
+ * @gid: A reference for per-protocol devres management.
+ * @users: A refcount to track effective users of this protocol.
+ * @priv: Reference for optional protocol private data.
+ * @ph: An embedded protocol handle that will be passed down to protocol
+ *	initialization code to identify this instance.
+ *
+ * Each protocol is initialized independently once for each SCMI platform in
+ * which is defined by DT and implemented by the SCMI server fw.
+ */
+struct scmi_protocol_instance {
+	const struct scmi_handle	*handle;
+	const struct scmi_protocol	*proto;
+	void				*gid;
+	refcount_t			users;
+	void				*priv;
+	struct scmi_protocol_handle	ph;
+};
+
+#define ph_to_pi(h)	container_of(h, struct scmi_protocol_instance, ph)
+
+/**
  * struct scmi_info - Structure representing a SCMI instance
  *
  * @dev: Device pointer
@@ -75,10 +114,18 @@
  *	implementation version and (sub-)vendor identification.
  * @handle: Instance of SCMI handle to send to clients
  * @tx_minfo: Universal Transmit Message management info
+ * @rx_minfo: Universal Receive Message management info
  * @tx_idr: IDR object to map protocol id to Tx channel info pointer
  * @rx_idr: IDR object to map protocol id to Rx channel info pointer
+ * @protocols: IDR for protocols' instance descriptors initialized for
+ *	       this SCMI instance: populated on protocol's first attempted
+ *	       usage.
+ * @protocols_mtx: A mutex to protect protocols instances initialization.
  * @protocols_imp: List of protocols implemented, currently maximum of
  *	MAX_PROTOCOLS_IMP elements allocated by the base protocol
+ * @active_protocols: IDR storing device_nodes for protocols actually defined
+ *		      in the DT and confirmed as implemented by fw.
+ * @notify_priv: Pointer to private data structure specific to notifications.
  * @node: List head
  * @users: Number of users of this instance
  */
@@ -88,9 +135,15 @@
 	struct scmi_revision_info version;
 	struct scmi_handle handle;
 	struct scmi_xfers_info tx_minfo;
+	struct scmi_xfers_info rx_minfo;
 	struct idr tx_idr;
 	struct idr rx_idr;
+	struct idr protocols;
+	/* Ensure mutual exclusive access to protocols instance array */
+	struct mutex protocols_mtx;
 	u8 *protocols_imp;
+	struct idr active_protocols;
+	void *notify_priv;
 	struct list_head node;
 	int users;
 };
@@ -132,6 +185,25 @@
 {
 	dev_dbg(dev, "Message ID: %x Sequence ID: %x Protocol: %x\n",
 		hdr->id, hdr->seq, hdr->protocol_id);
+}
+
+void scmi_set_notification_instance_data(const struct scmi_handle *handle,
+					 void *priv)
+{
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	info->notify_priv = priv;
+	/* Ensure updated protocol private date are visible */
+	smp_wmb();
+}
+
+void *scmi_get_notification_instance_data(const struct scmi_handle *handle)
+{
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	/* Ensure protocols_private_data has been updated */
+	smp_rmb();
+	return info->notify_priv;
 }
 
 /**
@@ -201,6 +273,91 @@
 	spin_unlock_irqrestore(&minfo->xfer_lock, flags);
 }
 
+static void scmi_handle_notification(struct scmi_chan_info *cinfo, u32 msg_hdr)
+{
+	struct scmi_xfer *xfer;
+	struct device *dev = cinfo->dev;
+	struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+	struct scmi_xfers_info *minfo = &info->rx_minfo;
+	ktime_t ts;
+
+	ts = ktime_get_boottime();
+	xfer = scmi_xfer_get(cinfo->handle, minfo);
+	if (IS_ERR(xfer)) {
+		dev_err(dev, "failed to get free message slot (%ld)\n",
+			PTR_ERR(xfer));
+		info->desc->ops->clear_channel(cinfo);
+		return;
+	}
+
+	unpack_scmi_header(msg_hdr, &xfer->hdr);
+	scmi_dump_header_dbg(dev, &xfer->hdr);
+	info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size,
+					    xfer);
+	scmi_notify(cinfo->handle, xfer->hdr.protocol_id,
+		    xfer->hdr.id, xfer->rx.buf, xfer->rx.len, ts);
+
+	trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
+			   xfer->hdr.protocol_id, xfer->hdr.seq,
+			   MSG_TYPE_NOTIFICATION);
+
+	__scmi_xfer_put(minfo, xfer);
+
+	info->desc->ops->clear_channel(cinfo);
+}
+
+static void scmi_handle_response(struct scmi_chan_info *cinfo,
+				 u16 xfer_id, u8 msg_type)
+{
+	struct scmi_xfer *xfer;
+	struct device *dev = cinfo->dev;
+	struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+	struct scmi_xfers_info *minfo = &info->tx_minfo;
+
+	/* Are we even expecting this? */
+	if (!test_bit(xfer_id, minfo->xfer_alloc_table)) {
+		dev_err(dev, "message for %d is not expected!\n", xfer_id);
+		info->desc->ops->clear_channel(cinfo);
+		return;
+	}
+
+	xfer = &minfo->xfer_block[xfer_id];
+	/*
+	 * Even if a response was indeed expected on this slot at this point,
+	 * a buggy platform could wrongly reply feeding us an unexpected
+	 * delayed response we're not prepared to handle: bail-out safely
+	 * blaming firmware.
+	 */
+	if (unlikely(msg_type == MSG_TYPE_DELAYED_RESP && !xfer->async_done)) {
+		dev_err(dev,
+			"Delayed Response for %d not expected! Buggy F/W ?\n",
+			xfer_id);
+		info->desc->ops->clear_channel(cinfo);
+		/* It was unexpected, so nobody will clear the xfer if not us */
+		__scmi_xfer_put(minfo, xfer);
+		return;
+	}
+
+	/* rx.len could be shrunk in the sync do_xfer, so reset to maxsz */
+	if (msg_type == MSG_TYPE_DELAYED_RESP)
+		xfer->rx.len = info->desc->max_msg_size;
+
+	scmi_dump_header_dbg(dev, &xfer->hdr);
+
+	info->desc->ops->fetch_response(cinfo, xfer);
+
+	trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
+			   xfer->hdr.protocol_id, xfer->hdr.seq,
+			   msg_type);
+
+	if (msg_type == MSG_TYPE_DELAYED_RESP) {
+		info->desc->ops->clear_channel(cinfo);
+		complete(xfer->async_done);
+	} else {
+		complete(&xfer->done);
+	}
+}
+
 /**
  * scmi_rx_callback() - callback for receiving messages
  *
@@ -215,47 +372,34 @@
  */
 void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr)
 {
-	struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
-	struct scmi_xfers_info *minfo = &info->tx_minfo;
 	u16 xfer_id = MSG_XTRACT_TOKEN(msg_hdr);
 	u8 msg_type = MSG_XTRACT_TYPE(msg_hdr);
-	struct device *dev = cinfo->dev;
-	struct scmi_xfer *xfer;
 
-	if (msg_type == MSG_TYPE_NOTIFICATION)
-		return; /* Notifications not yet supported */
-
-	/* Are we even expecting this? */
-	if (!test_bit(xfer_id, minfo->xfer_alloc_table)) {
-		dev_err(dev, "message for %d is not expected!\n", xfer_id);
-		return;
+	switch (msg_type) {
+	case MSG_TYPE_NOTIFICATION:
+		scmi_handle_notification(cinfo, msg_hdr);
+		break;
+	case MSG_TYPE_COMMAND:
+	case MSG_TYPE_DELAYED_RESP:
+		scmi_handle_response(cinfo, xfer_id, msg_type);
+		break;
+	default:
+		WARN_ONCE(1, "received unknown msg_type:%d\n", msg_type);
+		break;
 	}
-
-	xfer = &minfo->xfer_block[xfer_id];
-
-	scmi_dump_header_dbg(dev, &xfer->hdr);
-
-	info->desc->ops->fetch_response(cinfo, xfer);
-
-	trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
-			   xfer->hdr.protocol_id, xfer->hdr.seq,
-			   msg_type);
-
-	if (msg_type == MSG_TYPE_DELAYED_RESP)
-		complete(xfer->async_done);
-	else
-		complete(&xfer->done);
 }
 
 /**
- * scmi_xfer_put() - Release a transmit message
+ * xfer_put() - Release a transmit message
  *
- * @handle: Pointer to SCMI entity handle
+ * @ph: Pointer to SCMI protocol handle
  * @xfer: message that was reserved by scmi_xfer_get
  */
-void scmi_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
+static void xfer_put(const struct scmi_protocol_handle *ph,
+		     struct scmi_xfer *xfer)
 {
-	struct scmi_info *info = handle_to_scmi_info(handle);
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+	struct scmi_info *info = handle_to_scmi_info(pi->handle);
 
 	__scmi_xfer_put(&info->tx_minfo, xfer);
 }
@@ -272,22 +416,31 @@
 }
 
 /**
- * scmi_do_xfer() - Do one transfer
+ * do_xfer() - Do one transfer
  *
- * @handle: Pointer to SCMI entity handle
+ * @ph: Pointer to SCMI protocol handle
  * @xfer: Transfer to initiate and wait for response
  *
  * Return: -ETIMEDOUT in case of no response, if transmit error,
  *	return corresponding error, else if all goes well,
  *	return 0.
  */
-int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer)
+static int do_xfer(const struct scmi_protocol_handle *ph,
+		   struct scmi_xfer *xfer)
 {
 	int ret;
 	int timeout;
-	struct scmi_info *info = handle_to_scmi_info(handle);
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+	struct scmi_info *info = handle_to_scmi_info(pi->handle);
 	struct device *dev = info->dev;
 	struct scmi_chan_info *cinfo;
+
+	/*
+	 * Re-instate protocol id here from protocol handle so that cannot be
+	 * overridden by mistake (or malice) by the protocol code mangling with
+	 * the scmi_xfer structure.
+	 */
+	xfer->hdr.protocol_id = pi->proto->id;
 
 	cinfo = idr_find(&info->tx_idr, xfer->hdr.protocol_id);
 	if (unlikely(!cinfo))
@@ -315,6 +468,7 @@
 	} else {
 		/* And we wait for the response. */
 		timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms);
+		trace_android_vh_scmi_timeout_sync(&timeout);
 		if (!wait_for_completion_timeout(&xfer->done, timeout)) {
 			dev_err(dev, "timed out in resp(caller: %pS)\n",
 				(void *)_RET_IP_);
@@ -329,46 +483,60 @@
 		info->desc->ops->mark_txdone(cinfo, ret);
 
 	trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id,
-			    xfer->hdr.protocol_id, xfer->hdr.seq,
-			    xfer->hdr.status);
+			    xfer->hdr.protocol_id, xfer->hdr.seq, ret);
 
 	return ret;
+}
+
+static void reset_rx_to_maxsz(const struct scmi_protocol_handle *ph,
+			      struct scmi_xfer *xfer)
+{
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+	struct scmi_info *info = handle_to_scmi_info(pi->handle);
+
+	xfer->rx.len = info->desc->max_msg_size;
 }
 
 #define SCMI_MAX_RESPONSE_TIMEOUT	(2 * MSEC_PER_SEC)
 
 /**
- * scmi_do_xfer_with_response() - Do one transfer and wait until the delayed
+ * do_xfer_with_response() - Do one transfer and wait until the delayed
  *	response is received
  *
- * @handle: Pointer to SCMI entity handle
+ * @ph: Pointer to SCMI protocol handle
  * @xfer: Transfer to initiate and wait for response
  *
  * Return: -ETIMEDOUT in case of no delayed response, if transmit error,
  *	return corresponding error, else if all goes well, return 0.
  */
-int scmi_do_xfer_with_response(const struct scmi_handle *handle,
-			       struct scmi_xfer *xfer)
+static int do_xfer_with_response(const struct scmi_protocol_handle *ph,
+				 struct scmi_xfer *xfer)
 {
 	int ret, timeout = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT);
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
 	DECLARE_COMPLETION_ONSTACK(async_response);
+
+	xfer->hdr.protocol_id = pi->proto->id;
 
 	xfer->async_done = &async_response;
 
-	ret = scmi_do_xfer(handle, xfer);
-	if (!ret && !wait_for_completion_timeout(xfer->async_done, timeout))
-		ret = -ETIMEDOUT;
+	ret = do_xfer(ph, xfer);
+	if (!ret) {
+		if (!wait_for_completion_timeout(xfer->async_done, timeout))
+			ret = -ETIMEDOUT;
+		else if (xfer->hdr.status)
+			ret = scmi_to_linux_errno(xfer->hdr.status);
+	}
 
 	xfer->async_done = NULL;
 	return ret;
 }
 
 /**
- * scmi_xfer_get_init() - Allocate and initialise one message for transmit
+ * xfer_get_init() - Allocate and initialise one message for transmit
  *
- * @handle: Pointer to SCMI entity handle
+ * @ph: Pointer to SCMI protocol handle
  * @msg_id: Message identifier
- * @prot_id: Protocol identifier for the message
  * @tx_size: transmit message size
  * @rx_size: receive message size
  * @p: pointer to the allocated and initialised message
@@ -379,12 +547,14 @@
  * Return: 0 if all went fine with @p pointing to message, else
  *	corresponding error.
  */
-int scmi_xfer_get_init(const struct scmi_handle *handle, u8 msg_id, u8 prot_id,
-		       size_t tx_size, size_t rx_size, struct scmi_xfer **p)
+static int xfer_get_init(const struct scmi_protocol_handle *ph,
+			 u8 msg_id, size_t tx_size, size_t rx_size,
+			 struct scmi_xfer **p)
 {
 	int ret;
 	struct scmi_xfer *xfer;
-	struct scmi_info *info = handle_to_scmi_info(handle);
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+	struct scmi_info *info = handle_to_scmi_info(pi->handle);
 	struct scmi_xfers_info *minfo = &info->tx_minfo;
 	struct device *dev = info->dev;
 
@@ -393,7 +563,7 @@
 	    tx_size > info->desc->max_msg_size)
 		return -ERANGE;
 
-	xfer = scmi_xfer_get(handle, minfo);
+	xfer = scmi_xfer_get(pi->handle, minfo);
 	if (IS_ERR(xfer)) {
 		ret = PTR_ERR(xfer);
 		dev_err(dev, "failed to get free message slot(%d)\n", ret);
@@ -403,7 +573,7 @@
 	xfer->tx.len = tx_size;
 	xfer->rx.len = rx_size ? : info->desc->max_msg_size;
 	xfer->hdr.id = msg_id;
-	xfer->hdr.protocol_id = prot_id;
+	xfer->hdr.protocol_id = pi->proto->id;
 	xfer->hdr.poll_completion = false;
 
 	*p = xfer;
@@ -412,42 +582,237 @@
 }
 
 /**
- * scmi_version_get() - command to get the revision of the SCMI entity
+ * version_get() - command to get the revision of the SCMI entity
  *
- * @handle: Pointer to SCMI entity handle
- * @protocol: Protocol identifier for the message
+ * @ph: Pointer to SCMI protocol handle
  * @version: Holds returned version of protocol.
  *
  * Updates the SCMI information in the internal data structure.
  *
  * Return: 0 if all went fine, else return appropriate error.
  */
-int scmi_version_get(const struct scmi_handle *handle, u8 protocol,
-		     u32 *version)
+static int version_get(const struct scmi_protocol_handle *ph, u32 *version)
 {
 	int ret;
 	__le32 *rev_info;
 	struct scmi_xfer *t;
 
-	ret = scmi_xfer_get_init(handle, PROTOCOL_VERSION, protocol, 0,
-				 sizeof(*version), &t);
+	ret = xfer_get_init(ph, PROTOCOL_VERSION, 0, sizeof(*version), &t);
 	if (ret)
 		return ret;
 
-	ret = scmi_do_xfer(handle, t);
+	ret = do_xfer(ph, t);
 	if (!ret) {
 		rev_info = t->rx.buf;
 		*version = le32_to_cpu(*rev_info);
 	}
 
-	scmi_xfer_put(handle, t);
+	xfer_put(ph, t);
 	return ret;
 }
 
-void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
-				     u8 *prot_imp)
+/**
+ * scmi_set_protocol_priv  - Set protocol specific data at init time
+ *
+ * @ph: A reference to the protocol handle.
+ * @priv: The private data to set.
+ *
+ * Return: 0 on Success
+ */
+static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph,
+				  void *priv)
+{
+	struct scmi_protocol_instance *pi = ph_to_pi(ph);
+
+	pi->priv = priv;
+
+	return 0;
+}
+
+/**
+ * scmi_get_protocol_priv  - Set protocol specific data at init time
+ *
+ * @ph: A reference to the protocol handle.
+ *
+ * Return: Protocol private data if any was set.
+ */
+static void *scmi_get_protocol_priv(const struct scmi_protocol_handle *ph)
+{
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+
+	return pi->priv;
+}
+
+static const struct scmi_xfer_ops xfer_ops = {
+	.version_get = version_get,
+	.xfer_get_init = xfer_get_init,
+	.reset_rx_to_maxsz = reset_rx_to_maxsz,
+	.do_xfer = do_xfer,
+	.do_xfer_with_response = do_xfer_with_response,
+	.xfer_put = xfer_put,
+};
+
+/**
+ * scmi_get_revision_area  - Retrieve version memory area.
+ *
+ * @ph: A reference to the protocol handle.
+ *
+ * A helper to grab the version memory area reference during SCMI Base protocol
+ * initialization.
+ *
+ * Return: A reference to the version memory area associated to the SCMI
+ *	   instance underlying this protocol handle.
+ */
+struct scmi_revision_info *
+scmi_get_revision_area(const struct scmi_protocol_handle *ph)
+{
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+
+	return pi->handle->version;
+}
+
+/**
+ * scmi_get_protocol_instance  - Protocol initialization helper.
+ * @handle: A reference to the SCMI platform instance.
+ * @protocol_id: The protocol being requested.
+ *
+ * In case the required protocol has never been requested before for this
+ * instance, allocate and initialize all the needed structures while handling
+ * resource allocation with a dedicated per-protocol devres subgroup.
+ *
+ * Return: A reference to an initialized protocol instance or error on failure.
+ */
+static struct scmi_protocol_instance * __must_check
+scmi_get_protocol_instance(const struct scmi_handle *handle, u8 protocol_id)
+{
+	int ret = -ENOMEM;
+	void *gid;
+	struct scmi_protocol_instance *pi;
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	mutex_lock(&info->protocols_mtx);
+	pi = idr_find(&info->protocols, protocol_id);
+
+	if (pi) {
+		refcount_inc(&pi->users);
+	} else {
+		const struct scmi_protocol *proto;
+
+		/* Fail if protocol not registered on bus */
+		proto = scmi_get_protocol(protocol_id);
+		if (!proto) {
+			ret = -EPROBE_DEFER;
+			goto out;
+		}
+
+		/* Protocol specific devres group */
+		gid = devres_open_group(handle->dev, NULL, GFP_KERNEL);
+		if (!gid)
+			goto out;
+
+		pi = devm_kzalloc(handle->dev, sizeof(*pi), GFP_KERNEL);
+		if (!pi)
+			goto clean;
+
+		pi->gid = gid;
+		pi->proto = proto;
+		pi->handle = handle;
+		pi->ph.dev = handle->dev;
+		pi->ph.xops = &xfer_ops;
+		pi->ph.set_priv = scmi_set_protocol_priv;
+		pi->ph.get_priv = scmi_get_protocol_priv;
+		refcount_set(&pi->users, 1);
+		/* proto->init is assured NON NULL by scmi_protocol_register */
+		ret = pi->proto->init_instance(&pi->ph);
+		if (ret)
+			goto clean;
+
+		ret = idr_alloc(&info->protocols, pi,
+				protocol_id, protocol_id + 1, GFP_KERNEL);
+		if (ret != protocol_id)
+			goto clean;
+
+		if (pi->proto->events)
+			scmi_register_protocol_events(handle, pi->proto->id,
+						      &pi->ph,
+						      pi->proto->events);
+
+		devres_close_group(handle->dev, pi->gid);
+		dev_dbg(handle->dev, "Initialized protocol: 0x%X\n",
+			protocol_id);
+	}
+	mutex_unlock(&info->protocols_mtx);
+
+	return pi;
+
+clean:
+	scmi_put_protocol(protocol_id);
+	devres_release_group(handle->dev, gid);
+out:
+	mutex_unlock(&info->protocols_mtx);
+	return ERR_PTR(ret);
+}
+
+/**
+ * scmi_acquire_protocol  - Protocol acquire
+ * @handle: A reference to the SCMI platform instance.
+ * @protocol_id: The protocol being requested.
+ *
+ * Register a new user for the requested protocol on the specified SCMI
+ * platform instance, possibly triggering its initialization on first user.
+ *
+ * Return: 0 if protocol was acquired successfully.
+ */
+int scmi_acquire_protocol(const struct scmi_handle *handle, u8 protocol_id)
+{
+	return PTR_ERR_OR_ZERO(scmi_get_protocol_instance(handle, protocol_id));
+}
+
+/**
+ * scmi_release_protocol  - Protocol de-initialization helper.
+ * @handle: A reference to the SCMI platform instance.
+ * @protocol_id: The protocol being requested.
+ *
+ * Remove one user for the specified protocol and triggers de-initialization
+ * and resources de-allocation once the last user has gone.
+ */
+void scmi_release_protocol(const struct scmi_handle *handle, u8 protocol_id)
 {
 	struct scmi_info *info = handle_to_scmi_info(handle);
+	struct scmi_protocol_instance *pi;
+
+	mutex_lock(&info->protocols_mtx);
+	pi = idr_find(&info->protocols, protocol_id);
+	if (WARN_ON(!pi))
+		goto out;
+
+	if (refcount_dec_and_test(&pi->users)) {
+		void *gid = pi->gid;
+
+		if (pi->proto->events)
+			scmi_deregister_protocol_events(handle, protocol_id);
+
+		if (pi->proto->deinit_instance)
+			pi->proto->deinit_instance(&pi->ph);
+
+		idr_remove(&info->protocols, protocol_id);
+
+		scmi_put_protocol(protocol_id);
+
+		devres_release_group(handle->dev, gid);
+		dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n",
+			protocol_id);
+	}
+
+out:
+	mutex_unlock(&info->protocols_mtx);
+}
+
+void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
+				     u8 *prot_imp)
+{
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+	struct scmi_info *info = handle_to_scmi_info(pi->handle);
 
 	info->protocols_imp = prot_imp;
 }
@@ -465,6 +830,141 @@
 		if (info->protocols_imp[i] == prot_id)
 			return true;
 	return false;
+}
+
+struct scmi_protocol_devres {
+	const struct scmi_handle *handle;
+	u8 protocol_id;
+};
+
+static void scmi_devm_release_protocol(struct device *dev, void *res)
+{
+	struct scmi_protocol_devres *dres = res;
+
+	scmi_release_protocol(dres->handle, dres->protocol_id);
+}
+
+static struct scmi_protocol_instance __must_check *
+__scmi_devres_get_protocol_instance(struct scmi_device *sdev, u8 protocol_id)
+{
+	struct scmi_protocol_devres *dres;
+	struct scmi_protocol_instance *pi;
+
+	dres = devres_alloc(scmi_devm_release_protocol,
+			    sizeof(*dres), GFP_KERNEL);
+	if (!dres)
+		return ERR_PTR(-ENOMEM);
+
+	pi = scmi_get_protocol_instance(sdev->handle, protocol_id);
+	if (IS_ERR(pi)) {
+		devres_free(dres);
+		return pi;
+	}
+
+	dres->handle = sdev->handle;
+	dres->protocol_id = protocol_id;
+	devres_add(&sdev->dev, dres);
+
+	return pi;
+}
+
+/**
+ * scmi_devm_get_protocol  - Devres managed get protocol operations and handle
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ *	  be used for devres accounting.
+ * @protocol_id: The protocol being requested.
+ * @ph: A pointer reference used to pass back the associated protocol handle.
+ *
+ * Get hold of a protocol accounting for its usage, eventually triggering its
+ * initialization, and returning the protocol specific operations and related
+ * protocol handle which will be used as first argument in most of the
+ * protocols operations methods.
+ * Being a devres based managed method, protocol hold will be automatically
+ * released, and possibly de-initialized on last user, once the SCMI driver
+ * owning the scmi_device is unbound from it.
+ *
+ * Return: A reference to the requested protocol operations or error.
+ *	   Must be checked for errors by caller.
+ */
+static const void __must_check *
+scmi_devm_get_protocol(struct scmi_device *sdev, u8 protocol_id,
+		       struct scmi_protocol_handle **ph)
+{
+	struct scmi_protocol_instance *pi;
+
+	if (!ph)
+		return ERR_PTR(-EINVAL);
+
+	pi = __scmi_devres_get_protocol_instance(sdev, protocol_id);
+	if (IS_ERR(pi))
+		return pi;
+
+	*ph = &pi->ph;
+
+	return pi->proto->ops;
+}
+
+/**
+ * scmi_devm_acquire_protocol  - Devres managed helper to get hold of a protocol
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ *	  be used for devres accounting.
+ * @protocol_id: The protocol being requested.
+ *
+ * Get hold of a protocol accounting for its usage, possibly triggering its
+ * initialization but without getting access to its protocol specific operations
+ * and handle.
+ *
+ * Being a devres based managed method, protocol hold will be automatically
+ * released, and possibly de-initialized on last user, once the SCMI driver
+ * owning the scmi_device is unbound from it.
+ *
+ * Return: 0 on SUCCESS
+ */
+static int __must_check scmi_devm_acquire_protocol(struct scmi_device *sdev,
+						   u8 protocol_id)
+{
+	struct scmi_protocol_instance *pi;
+
+	pi = __scmi_devres_get_protocol_instance(sdev, protocol_id);
+	if (IS_ERR(pi))
+		return PTR_ERR(pi);
+
+	return 0;
+}
+
+static int scmi_devm_protocol_match(struct device *dev, void *res, void *data)
+{
+	struct scmi_protocol_devres *dres = res;
+
+	if (WARN_ON(!dres || !data))
+		return 0;
+
+	return dres->protocol_id == *((u8 *)data);
+}
+
+/**
+ * scmi_devm_put_protocol  - Devres managed put protocol operations and handle
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ *	  be used for devres accounting.
+ * @protocol_id: The protocol being requested.
+ *
+ * Explicitly release a protocol hold previously obtained calling the above
+ * @scmi_devm_get_protocol_ops.
+ */
+static void scmi_devm_put_protocol(struct scmi_device *sdev, u8 protocol_id)
+{
+	int ret;
+
+	ret = devres_release(&sdev->dev, scmi_devm_release_protocol,
+			     scmi_devm_protocol_match, &protocol_id);
+	WARN_ON(ret);
+}
+
+static inline
+struct scmi_handle *scmi_handle_get_from_info(struct scmi_info *info)
+{
+	info->users++;
+	return &info->handle;
 }
 
 /**
@@ -488,8 +988,7 @@
 	list_for_each(p, &scmi_list) {
 		info = list_entry(p, struct scmi_info, node);
 		if (dev->parent == info->dev) {
-			handle = &info->handle;
-			info->users++;
+			handle = scmi_handle_get_from_info(info);
 			break;
 		}
 	}
@@ -526,13 +1025,13 @@
 	return 0;
 }
 
-static int scmi_xfer_info_init(struct scmi_info *sinfo)
+static int __scmi_xfer_info_init(struct scmi_info *sinfo,
+				 struct scmi_xfers_info *info)
 {
 	int i;
 	struct scmi_xfer *xfer;
 	struct device *dev = sinfo->dev;
 	const struct scmi_desc *desc = sinfo->desc;
-	struct scmi_xfers_info *info = &sinfo->tx_minfo;
 
 	/* Pre-allocated messages, no more than what hdr.seq can support */
 	if (WARN_ON(!desc->max_msg || desc->max_msg > MSG_TOKEN_MAX)) {
@@ -566,6 +1065,16 @@
 	spin_lock_init(&info->xfer_lock);
 
 	return 0;
+}
+
+static int scmi_xfer_info_init(struct scmi_info *sinfo)
+{
+	int ret = __scmi_xfer_info_init(sinfo, &sinfo->tx_minfo);
+
+	if (!ret && idr_find(&sinfo->rx_idr, SCMI_PROTOCOL_BASE))
+		ret = __scmi_xfer_info_init(sinfo, &sinfo->rx_minfo);
+
+	return ret;
 }
 
 static int scmi_chan_setup(struct scmi_info *info, struct device *dev,
@@ -617,10 +1126,59 @@
 {
 	int ret = scmi_chan_setup(info, dev, prot_id, true);
 
-	if (!ret) /* Rx is optional, hence no error check */
-		scmi_chan_setup(info, dev, prot_id, false);
+	if (!ret) {
+		/* Rx is optional, report only memory errors */
+		ret = scmi_chan_setup(info, dev, prot_id, false);
+		if (ret && ret != -ENOMEM)
+			ret = 0;
+	}
 
 	return ret;
+}
+
+/**
+ * scmi_get_protocol_device  - Helper to get/create an SCMI device.
+ *
+ * @np: A device node representing a valid active protocols for the referred
+ * SCMI instance.
+ * @info: The referred SCMI instance for which we are getting/creating this
+ * device.
+ * @prot_id: The protocol ID.
+ * @name: The device name.
+ *
+ * Referring to the specific SCMI instance identified by @info, this helper
+ * takes care to return a properly initialized device matching the requested
+ * @proto_id and @name: if device was still not existent it is created as a
+ * child of the specified SCMI instance @info and its transport properly
+ * initialized as usual.
+ */
+static inline struct scmi_device *
+scmi_get_protocol_device(struct device_node *np, struct scmi_info *info,
+			 int prot_id, const char *name)
+{
+	struct scmi_device *sdev;
+
+	/* Already created for this parent SCMI instance ? */
+	sdev = scmi_find_child_dev(info->dev, prot_id, name);
+	if (sdev)
+		return sdev;
+
+	pr_debug("Creating SCMI device (%s) for protocol %x\n", name, prot_id);
+
+	sdev = scmi_device_create(np, info->dev, prot_id, name);
+	if (!sdev) {
+		dev_err(info->dev, "failed to create %d protocol device\n",
+			prot_id);
+		return NULL;
+	}
+
+	if (scmi_txrx_setup(info, &sdev->dev, prot_id)) {
+		dev_err(&sdev->dev, "failed to setup transport\n");
+		scmi_device_destroy(sdev);
+		return NULL;
+	}
+
+	return sdev;
 }
 
 static inline void
@@ -629,55 +1187,231 @@
 {
 	struct scmi_device *sdev;
 
-	sdev = scmi_device_create(np, info->dev, prot_id, name);
-	if (!sdev) {
-		dev_err(info->dev, "failed to create %d protocol device\n",
-			prot_id);
+	sdev = scmi_get_protocol_device(np, info, prot_id, name);
+	if (!sdev)
 		return;
-	}
-
-	if (scmi_txrx_setup(info, &sdev->dev, prot_id)) {
-		dev_err(&sdev->dev, "failed to setup transport\n");
-		scmi_device_destroy(sdev);
-		return;
-	}
 
 	/* setup handle now as the transport is ready */
 	scmi_set_handle(sdev);
 }
 
-#define MAX_SCMI_DEV_PER_PROTOCOL	2
-struct scmi_prot_devnames {
-	int protocol_id;
-	char *names[MAX_SCMI_DEV_PER_PROTOCOL];
-};
-
-static struct scmi_prot_devnames devnames[] = {
-	{ SCMI_PROTOCOL_POWER,  { "genpd" },},
-	{ SCMI_PROTOCOL_PERF,   { "cpufreq" },},
-	{ SCMI_PROTOCOL_CLOCK,  { "clocks" },},
-	{ SCMI_PROTOCOL_SENSOR, { "hwmon" },},
-	{ SCMI_PROTOCOL_RESET,  { "reset" },},
-};
-
-static inline void
-scmi_create_protocol_devices(struct device_node *np, struct scmi_info *info,
-			     int prot_id)
+/**
+ * scmi_create_protocol_devices  - Create devices for all pending requests for
+ * this SCMI instance.
+ *
+ * @np: The device node describing the protocol
+ * @info: The SCMI instance descriptor
+ * @prot_id: The protocol ID
+ *
+ * All devices previously requested for this instance (if any) are found and
+ * created by scanning the proper @&scmi_requested_devices entry.
+ */
+static void scmi_create_protocol_devices(struct device_node *np,
+					 struct scmi_info *info, int prot_id)
 {
-	int loop, cnt;
+	struct list_head *phead;
 
-	for (loop = 0; loop < ARRAY_SIZE(devnames); loop++) {
-		if (devnames[loop].protocol_id != prot_id)
-			continue;
+	mutex_lock(&scmi_requested_devices_mtx);
+	phead = idr_find(&scmi_requested_devices, prot_id);
+	if (phead) {
+		struct scmi_requested_dev *rdev;
 
-		for (cnt = 0; cnt < ARRAY_SIZE(devnames[loop].names); cnt++) {
-			const char *name = devnames[loop].names[cnt];
+		list_for_each_entry(rdev, phead, node)
+			scmi_create_protocol_device(np, info, prot_id,
+						    rdev->id_table->name);
+	}
+	mutex_unlock(&scmi_requested_devices_mtx);
+}
 
-			if (name)
-				scmi_create_protocol_device(np, info, prot_id,
-							    name);
+/**
+ * scmi_request_protocol_device  - Helper to request a device
+ *
+ * @id_table: A protocol/name pair descriptor for the device to be created.
+ *
+ * This helper let an SCMI driver request specific devices identified by the
+ * @id_table to be created for each active SCMI instance.
+ *
+ * The requested device name MUST NOT be already existent for any protocol;
+ * at first the freshly requested @id_table is annotated in the IDR table
+ * @scmi_requested_devices, then a matching device is created for each already
+ * active SCMI instance. (if any)
+ *
+ * This way the requested device is created straight-away for all the already
+ * initialized(probed) SCMI instances (handles) and it remains also annotated
+ * as pending creation if the requesting SCMI driver was loaded before some
+ * SCMI instance and related transports were available: when such late instance
+ * is probed, its probe will take care to scan the list of pending requested
+ * devices and create those on its own (see @scmi_create_protocol_devices and
+ * its enclosing loop)
+ *
+ * Return: 0 on Success
+ */
+int scmi_request_protocol_device(const struct scmi_device_id *id_table)
+{
+	int ret = 0;
+	unsigned int id = 0;
+	struct list_head *head, *phead = NULL;
+	struct scmi_requested_dev *rdev;
+	struct scmi_info *info;
+
+	pr_debug("Requesting SCMI device (%s) for protocol %x\n",
+		 id_table->name, id_table->protocol_id);
+
+	/*
+	 * Search for the matching protocol rdev list and then search
+	 * of any existent equally named device...fails if any duplicate found.
+	 */
+	mutex_lock(&scmi_requested_devices_mtx);
+	idr_for_each_entry(&scmi_requested_devices, head, id) {
+		if (!phead) {
+			/* A list found registered in the IDR is never empty */
+			rdev = list_first_entry(head, struct scmi_requested_dev,
+						node);
+			if (rdev->id_table->protocol_id ==
+			    id_table->protocol_id)
+				phead = head;
+		}
+		list_for_each_entry(rdev, head, node) {
+			if (!strcmp(rdev->id_table->name, id_table->name)) {
+				pr_err("Ignoring duplicate request [%d] %s\n",
+				       rdev->id_table->protocol_id,
+				       rdev->id_table->name);
+				ret = -EINVAL;
+				goto out;
+			}
 		}
 	}
+
+	/*
+	 * No duplicate found for requested id_table, so let's create a new
+	 * requested device entry for this new valid request.
+	 */
+	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+	if (!rdev) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	rdev->id_table = id_table;
+
+	/*
+	 * Append the new requested device table descriptor to the head of the
+	 * related protocol list, eventually creating such head if not already
+	 * there.
+	 */
+	if (!phead) {
+		phead = kzalloc(sizeof(*phead), GFP_KERNEL);
+		if (!phead) {
+			kfree(rdev);
+			ret = -ENOMEM;
+			goto out;
+		}
+		INIT_LIST_HEAD(phead);
+
+		ret = idr_alloc(&scmi_requested_devices, (void *)phead,
+				id_table->protocol_id,
+				id_table->protocol_id + 1, GFP_KERNEL);
+		if (ret != id_table->protocol_id) {
+			pr_err("Failed to save SCMI device - ret:%d\n", ret);
+			kfree(rdev);
+			kfree(phead);
+			ret = -EINVAL;
+			goto out;
+		}
+		ret = 0;
+	}
+	list_add(&rdev->node, phead);
+
+	/*
+	 * Now effectively create and initialize the requested device for every
+	 * already initialized SCMI instance which has registered the requested
+	 * protocol as a valid active one: i.e. defined in DT and supported by
+	 * current platform FW.
+	 */
+	mutex_lock(&scmi_list_mutex);
+	list_for_each_entry(info, &scmi_list, node) {
+		struct device_node *child;
+
+		child = idr_find(&info->active_protocols,
+				 id_table->protocol_id);
+		if (child) {
+			struct scmi_device *sdev;
+
+			sdev = scmi_get_protocol_device(child, info,
+							id_table->protocol_id,
+							id_table->name);
+			/* Set handle if not already set: device existed */
+			if (sdev && !sdev->handle)
+				sdev->handle = scmi_handle_get_from_info(info);
+		} else {
+			dev_err(info->dev,
+				"Failed. SCMI protocol %d not active.\n",
+				id_table->protocol_id);
+		}
+	}
+	mutex_unlock(&scmi_list_mutex);
+
+out:
+	mutex_unlock(&scmi_requested_devices_mtx);
+
+	return ret;
+}
+
+/**
+ * scmi_unrequest_protocol_device  - Helper to unrequest a device
+ *
+ * @id_table: A protocol/name pair descriptor for the device to be unrequested.
+ *
+ * An helper to let an SCMI driver release its request about devices; note that
+ * devices are created and initialized once the first SCMI driver request them
+ * but they destroyed only on SCMI core unloading/unbinding.
+ *
+ * The current SCMI transport layer uses such devices as internal references and
+ * as such they could be shared as same transport between multiple drivers so
+ * that cannot be safely destroyed till the whole SCMI stack is removed.
+ * (unless adding further burden of refcounting.)
+ */
+void scmi_unrequest_protocol_device(const struct scmi_device_id *id_table)
+{
+	struct list_head *phead;
+
+	pr_debug("Unrequesting SCMI device (%s) for protocol %x\n",
+		 id_table->name, id_table->protocol_id);
+
+	mutex_lock(&scmi_requested_devices_mtx);
+	phead = idr_find(&scmi_requested_devices, id_table->protocol_id);
+	if (phead) {
+		struct scmi_requested_dev *victim, *tmp;
+
+		list_for_each_entry_safe(victim, tmp, phead, node) {
+			if (!strcmp(victim->id_table->name, id_table->name)) {
+				list_del(&victim->node);
+				kfree(victim);
+				break;
+			}
+		}
+
+		if (list_empty(phead)) {
+			idr_remove(&scmi_requested_devices,
+				   id_table->protocol_id);
+			kfree(phead);
+		}
+	}
+	mutex_unlock(&scmi_requested_devices_mtx);
+}
+
+static int scmi_cleanup_txrx_channels(struct scmi_info *info)
+{
+	int ret;
+	struct idr *idr = &info->tx_idr;
+
+	ret = idr_for_each(idr, info->desc->ops->chan_free, idr);
+	idr_destroy(&info->tx_idr);
+
+	idr = &info->rx_idr;
+	ret = idr_for_each(idr, info->desc->ops->chan_free, idr);
+	idr_destroy(&info->rx_idr);
+
+	return ret;
 }
 
 static int scmi_probe(struct platform_device *pdev)
@@ -700,10 +1434,9 @@
 	info->dev = dev;
 	info->desc = desc;
 	INIT_LIST_HEAD(&info->node);
-
-	ret = scmi_xfer_info_init(info);
-	if (ret)
-		return ret;
+	idr_init(&info->protocols);
+	mutex_init(&info->protocols_mtx);
+	idr_init(&info->active_protocols);
 
 	platform_set_drvdata(pdev, info);
 	idr_init(&info->tx_idr);
@@ -712,15 +1445,30 @@
 	handle = &info->handle;
 	handle->dev = info->dev;
 	handle->version = &info->version;
+	handle->devm_acquire_protocol = scmi_devm_acquire_protocol;
+	handle->devm_get_protocol = scmi_devm_get_protocol;
+	handle->devm_put_protocol = scmi_devm_put_protocol;
 
 	ret = scmi_txrx_setup(info, dev, SCMI_PROTOCOL_BASE);
 	if (ret)
 		return ret;
 
-	ret = scmi_base_protocol_init(handle);
+	ret = scmi_xfer_info_init(info);
+	if (ret)
+		goto clear_txrx_setup;
+
+	if (scmi_notification_init(handle))
+		dev_err(dev, "SCMI Notifications NOT available.\n");
+
+	/*
+	 * Trigger SCMI Base protocol initialization.
+	 * It's mandatory and won't be ever released/deinit until the
+	 * SCMI stack is shutdown/unloaded as a whole.
+	 */
+	ret = scmi_acquire_protocol(handle, SCMI_PROTOCOL_BASE);
 	if (ret) {
-		dev_err(dev, "unable to communicate with SCMI(%d)\n", ret);
-		return ret;
+		dev_err(dev, "unable to communicate with SCMI\n");
+		goto notification_exit;
 	}
 
 	mutex_lock(&scmi_list_mutex);
@@ -742,10 +1490,29 @@
 			continue;
 		}
 
+		/*
+		 * Save this valid DT protocol descriptor amongst
+		 * @active_protocols for this SCMI instance/
+		 */
+		ret = idr_alloc(&info->active_protocols, child,
+				prot_id, prot_id + 1, GFP_KERNEL);
+		if (ret != prot_id) {
+			dev_err(dev, "SCMI protocol %d already activated. Skip\n",
+				prot_id);
+			continue;
+		}
+
+		of_node_get(child);
 		scmi_create_protocol_devices(child, info, prot_id);
 	}
 
 	return 0;
+
+notification_exit:
+	scmi_notification_exit(&info->handle);
+clear_txrx_setup:
+	scmi_cleanup_txrx_channels(info);
+	return ret;
 }
 
 void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id)
@@ -755,9 +1522,9 @@
 
 static int scmi_remove(struct platform_device *pdev)
 {
-	int ret = 0;
+	int ret = 0, id;
 	struct scmi_info *info = platform_get_drvdata(pdev);
-	struct idr *idr = &info->tx_idr;
+	struct device_node *child;
 
 	mutex_lock(&scmi_list_mutex);
 	if (info->users)
@@ -769,21 +1536,72 @@
 	if (ret)
 		return ret;
 
+	scmi_notification_exit(&info->handle);
+
+	mutex_lock(&info->protocols_mtx);
+	idr_destroy(&info->protocols);
+	mutex_unlock(&info->protocols_mtx);
+
+	idr_for_each_entry(&info->active_protocols, child, id)
+		of_node_put(child);
+	idr_destroy(&info->active_protocols);
+
 	/* Safe to free channels since no more users */
-	ret = idr_for_each(idr, info->desc->ops->chan_free, idr);
-	idr_destroy(&info->tx_idr);
-
-	idr = &info->rx_idr;
-	ret = idr_for_each(idr, info->desc->ops->chan_free, idr);
-	idr_destroy(&info->rx_idr);
-
-	return ret;
+	return scmi_cleanup_txrx_channels(info);
 }
+
+static ssize_t protocol_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct scmi_info *info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u.%u\n", info->version.major_ver,
+		       info->version.minor_ver);
+}
+static DEVICE_ATTR_RO(protocol_version);
+
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct scmi_info *info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "0x%x\n", info->version.impl_ver);
+}
+static DEVICE_ATTR_RO(firmware_version);
+
+static ssize_t vendor_id_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct scmi_info *info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", info->version.vendor_id);
+}
+static DEVICE_ATTR_RO(vendor_id);
+
+static ssize_t sub_vendor_id_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct scmi_info *info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", info->version.sub_vendor_id);
+}
+static DEVICE_ATTR_RO(sub_vendor_id);
+
+static struct attribute *versions_attrs[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_protocol_version.attr,
+	&dev_attr_vendor_id.attr,
+	&dev_attr_sub_vendor_id.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(versions);
 
 /* Each compatible listed below must have descriptor associated with it */
 static const struct of_device_id scmi_of_match[] = {
+#ifdef CONFIG_MAILBOX
 	{ .compatible = "arm,scmi", .data = &scmi_mailbox_desc },
-#ifdef CONFIG_HAVE_ARM_SMCCC
+#endif
+#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
 	{ .compatible = "arm,scmi-smc", .data = &scmi_smc_desc},
 #endif
 	{ /* Sentinel */ },
@@ -794,7 +1612,9 @@
 static struct platform_driver scmi_driver = {
 	.driver = {
 		   .name = "arm-scmi",
+		   .suppress_bind_attrs = true,
 		   .of_match_table = scmi_of_match,
+		   .dev_groups = versions_groups,
 		   },
 	.probe = scmi_probe,
 	.remove = scmi_remove,
@@ -804,11 +1624,15 @@
 {
 	scmi_bus_init();
 
+	scmi_base_register();
+
 	scmi_clock_register();
 	scmi_perf_register();
 	scmi_power_register();
 	scmi_reset_register();
 	scmi_sensors_register();
+	scmi_voltage_register();
+	scmi_system_register();
 
 	return platform_driver_register(&scmi_driver);
 }
@@ -816,19 +1640,23 @@
 
 static void __exit scmi_driver_exit(void)
 {
-	scmi_bus_exit();
+	scmi_base_unregister();
 
 	scmi_clock_unregister();
 	scmi_perf_unregister();
 	scmi_power_unregister();
 	scmi_reset_unregister();
 	scmi_sensors_unregister();
+	scmi_voltage_unregister();
+	scmi_system_unregister();
+
+	scmi_bus_exit();
 
 	platform_driver_unregister(&scmi_driver);
 }
 module_exit(scmi_driver_exit);
 
-MODULE_ALIAS("platform: arm-scmi");
+MODULE_ALIAS("platform:arm-scmi");
 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 MODULE_DESCRIPTION("ARM SCMI protocol driver");
 MODULE_LICENSE("GPL v2");

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