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2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/thunderbolt/cap.c
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@@ -1,8 +1,9 @@
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 // SPDX-License-Identifier: GPL-2.0
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 /*
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- * Thunderbolt Cactus Ridge driver - capabilities lookup
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+ * Thunderbolt driver - capabilities lookup
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  *
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  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
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+ * Copyright (C) 2018, Intel Corporation
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  */
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 #include <linux/slab.h>
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@@ -12,14 +13,99 @@
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 #define CAP_OFFSET_MAX		0xff
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 #define VSE_CAP_OFFSET_MAX	0xffff
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+#define TMU_ACCESS_EN		BIT(20)
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-struct tb_cap_any {
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-	union {
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-		struct tb_cap_basic basic;
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-		struct tb_cap_extended_short extended_short;
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-		struct tb_cap_extended_long extended_long;
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-	};
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-} __packed;
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+static int tb_port_enable_tmu(struct tb_port *port, bool enable)
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+{
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+	struct tb_switch *sw = port->sw;
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+	u32 value, offset;
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+	int ret;
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+
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+	/*
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+	 * Legacy devices need to have TMU access enabled before port
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+	 * space can be fully accessed.
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+	 */
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+	if (tb_switch_is_light_ridge(sw))
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+		offset = 0x26;
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+	else if (tb_switch_is_eagle_ridge(sw))
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+		offset = 0x2a;
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+	else
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+		return 0;
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+
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+	ret = tb_sw_read(sw, &value, TB_CFG_SWITCH, offset, 1);
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+	if (ret)
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+		return ret;
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+
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+	if (enable)
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+		value |= TMU_ACCESS_EN;
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+	else
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+		value &= ~TMU_ACCESS_EN;
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+
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+	return tb_sw_write(sw, &value, TB_CFG_SWITCH, offset, 1);
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+}
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+
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+static void tb_port_dummy_read(struct tb_port *port)
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+{
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+	/*
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+	 * When reading from next capability pointer location in port
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+	 * config space the read data is not cleared on LR. To avoid
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+	 * reading stale data on next read perform one dummy read after
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+	 * port capabilities are walked.
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+	 */
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+	if (tb_switch_is_light_ridge(port->sw)) {
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+		u32 dummy;
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+
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+		tb_port_read(port, &dummy, TB_CFG_PORT, 0, 1);
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+	}
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+}
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+
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+/**
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+ * tb_port_next_cap() - Return next capability in the linked list
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+ * @port: Port to find the capability for
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+ * @offset: Previous capability offset (%0 for start)
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+ *
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+ * Returns dword offset of the next capability in port config space
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+ * capability list and returns it. Passing %0 returns the first entry in
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+ * the capability list. If no next capability is found returns %0. In case
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+ * of failure returns negative errno.
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+ */
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+int tb_port_next_cap(struct tb_port *port, unsigned int offset)
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+{
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+	struct tb_cap_any header;
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+	int ret;
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+
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+	if (!offset)
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+		return port->config.first_cap_offset;
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+
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+	ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
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+	if (ret)
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+		return ret;
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+
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+	return header.basic.next;
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+}
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+
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+static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
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+{
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+	int offset = 0;
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+
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+	do {
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+		struct tb_cap_any header;
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+		int ret;
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+
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+		offset = tb_port_next_cap(port, offset);
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+		if (offset < 0)
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+			return offset;
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+
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+		ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
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+		if (ret)
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+			return ret;
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+
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+		if (header.basic.cap == cap)
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+			return offset;
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+	} while (offset > 0);
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+
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+	return -ENOENT;
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+}
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 /**
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  * tb_port_find_cap() - Find port capability
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@@ -32,42 +118,84 @@
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  */
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 int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
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 {
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-	u32 offset;
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+	int ret;
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-	/*
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-	 * DP out adapters claim to implement TMU capability but in
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-	 * reality they do not so we hard code the adapter specific
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-	 * capability offset here.
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-	 */
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-	if (port->config.type == TB_TYPE_DP_HDMI_OUT)
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-		offset = 0x39;
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-	else
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-		offset = 0x1;
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+	ret = tb_port_enable_tmu(port, true);
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+	if (ret)
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+		return ret;
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+
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+	ret = __tb_port_find_cap(port, cap);
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+
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+	tb_port_dummy_read(port);
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+	tb_port_enable_tmu(port, false);
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+
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+	return ret;
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+}
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+
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+/**
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+ * tb_switch_next_cap() - Return next capability in the linked list
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+ * @sw: Switch to find the capability for
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+ * @offset: Previous capability offset (%0 for start)
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+ *
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+ * Finds dword offset of the next capability in router config space
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+ * capability list and returns it. Passing %0 returns the first entry in
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+ * the capability list. If no next capability is found returns %0. In case
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+ * of failure returns negative errno.
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+ */
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+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset)
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+{
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+	struct tb_cap_any header;
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+	int ret;
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+
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+	if (!offset)
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+		return sw->config.first_cap_offset;
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+
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+	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
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+	if (ret)
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+		return ret;
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+
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+	switch (header.basic.cap) {
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+	case TB_SWITCH_CAP_TMU:
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+		ret = header.basic.next;
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+		break;
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+
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+	case TB_SWITCH_CAP_VSE:
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+		if (!header.extended_short.length)
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+			ret = header.extended_long.next;
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+		else
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+			ret = header.extended_short.next;
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+		break;
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+
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+	default:
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+		tb_sw_dbg(sw, "unknown capability %#x at %#x\n",
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+			  header.basic.cap, offset);
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+		ret = -EINVAL;
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+		break;
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+	}
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+
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+	return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret;
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+}
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+
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+/**
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+ * tb_switch_find_cap() - Find switch capability
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+ * @sw Switch to find the capability for
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+ * @cap: Capability to look
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+ *
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+ * Returns offset to start of capability or %-ENOENT if no such
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+ * capability was found. Negative errno is returned if there was an
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+ * error.
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+ */
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+int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
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+{
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+	int offset = 0;
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 	do {
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 		struct tb_cap_any header;
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 		int ret;
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-		ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
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-		if (ret)
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-			return ret;
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-
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-		if (header.basic.cap == cap)
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+		offset = tb_switch_next_cap(sw, offset);
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+		if (offset < 0)
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 			return offset;
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-
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-		offset = header.basic.next;
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-	} while (offset);
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-
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-	return -ENOENT;
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-}
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-
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-static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
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-{
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-	int offset = sw->config.first_cap_offset;
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-
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-	while (offset > 0 && offset < CAP_OFFSET_MAX) {
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-		struct tb_cap_any header;
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-		int ret;
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 		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
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 		if (ret)
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@@ -75,9 +203,7 @@
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 		if (header.basic.cap == cap)
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 			return offset;
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-
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-		offset = header.basic.next;
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-	}
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+	} while (offset);
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 	return -ENOENT;
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 }
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@@ -94,37 +220,24 @@
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  */
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 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
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 {
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-	struct tb_cap_any header;
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-	int offset;
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+	int offset = 0;
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-	offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
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-	if (offset < 0)
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-		return offset;
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-
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-	while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
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+	do {
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+		struct tb_cap_any header;
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 		int ret;
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-		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
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+		offset = tb_switch_next_cap(sw, offset);
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+		if (offset < 0)
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+			return offset;
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+
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+		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
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 		if (ret)
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 			return ret;
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-		/*
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-		 * Extended vendor specific capabilities come in two
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-		 * flavors: short and long. The latter is used when
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-		 * offset is over 0xff.
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-		 */
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-		if (offset >= CAP_OFFSET_MAX) {
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-			if (header.extended_long.vsec_id == vsec)
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-				return offset;
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-			offset = header.extended_long.next;
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-		} else {
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-			if (header.extended_short.vsec_id == vsec)
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-				return offset;
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-			if (!header.extended_short.length)
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-				return -ENOENT;
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-			offset = header.extended_short.next;
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-		}
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-	}
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+		if (header.extended_short.cap == TB_SWITCH_CAP_VSE &&
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+		    header.extended_short.vsec_id == vsec)
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+			return offset;
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+	} while (offset);
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 	return -ENOENT;
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 }