From 5cda4a11b4906ddd037b216845e7f9c96ac93772 Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello@amd.com>
Date: Mon, 26 Sep 2022 09:33:50 -0500
Subject: [PATCH] thunderbolt: Explicitly enable lane adapter hotplug events at
 startup

commit 5d2569cb4a65c373896ec0217febdf88739ed295 upstream.

Software that has run before the USB4 CM in Linux runs may have disabled
hotplug events for a given lane adapter.

Other CMs such as that one distributed with Windows 11 will enable hotplug
events. Do the same thing in the Linux CM which fixes hotplug events on
"AMD Pink Sardine".

Cc: stable@vger.kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/thunderbolt/switch.c  | 24 ++++++++++++++++++++++++
 drivers/thunderbolt/tb.h      |  1 +
 drivers/thunderbolt/tb_regs.h |  1 +
 drivers/thunderbolt/usb4.c    | 20 ++++++++++++++++++++
 4 files changed, 46 insertions(+)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 50a5b160ccde..ef647477ab38 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -2690,6 +2690,26 @@ static void tb_switch_credits_init(struct tb_switch *sw)
 		tb_sw_info(sw, "failed to determine preferred buffer allocation, using defaults\n");
 }
 
+static int tb_switch_port_hotplug_enable(struct tb_switch *sw)
+{
+	struct tb_port *port;
+
+	if (tb_switch_is_icm(sw))
+		return 0;
+
+	tb_switch_for_each_port(sw, port) {
+		int res;
+
+		if (!port->cap_usb4)
+			continue;
+
+		res = usb4_port_hotplug_enable(port);
+		if (res)
+			return res;
+	}
+	return 0;
+}
+
 /**
  * tb_switch_add() - Add a switch to the domain
  * @sw: Switch to add
@@ -2761,6 +2781,10 @@ int tb_switch_add(struct tb_switch *sw)
 			return ret;
 	}
 
+	ret = tb_switch_port_hotplug_enable(sw);
+	if (ret)
+		return ret;
+
 	ret = device_add(&sw->dev);
 	if (ret) {
 		dev_err(&sw->dev, "failed to add device: %d\n", ret);
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 725104c83e3d..b535d296d37e 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1067,6 +1067,7 @@ int usb4_switch_add_ports(struct tb_switch *sw);
 void usb4_switch_remove_ports(struct tb_switch *sw);
 
 int usb4_port_unlock(struct tb_port *port);
+int usb4_port_hotplug_enable(struct tb_port *port);
 int usb4_port_configure(struct tb_port *port);
 void usb4_port_unconfigure(struct tb_port *port);
 int usb4_port_configure_xdomain(struct tb_port *port);
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 484f25be2849..67f21e6c1813 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -301,6 +301,7 @@ struct tb_regs_port_header {
 #define ADP_CS_5				0x05
 #define ADP_CS_5_LCA_MASK			GENMASK(28, 22)
 #define ADP_CS_5_LCA_SHIFT			22
+#define ADP_CS_5_DHP				BIT(31)
 
 /* TMU adapter registers */
 #define TMU_ADP_CS_3				0x03
diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index ceddbe7e9f93..90986567f1f9 100644
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -1068,6 +1068,26 @@ int usb4_port_unlock(struct tb_port *port)
 	return tb_port_write(port, &val, TB_CFG_PORT, ADP_CS_4, 1);
 }
 
+/**
+ * usb4_port_hotplug_enable() - Enables hotplug for a port
+ * @port: USB4 port to operate on
+ *
+ * Enables hot plug events on a given port. This is only intended
+ * to be used on lane, DP-IN, and DP-OUT adapters.
+ */
+int usb4_port_hotplug_enable(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT, ADP_CS_5, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_CS_5_DHP;
+	return tb_port_write(port, &val, TB_CFG_PORT, ADP_CS_5, 1);
+}
+
 static int usb4_port_set_configured(struct tb_port *port, bool configured)
 {
 	int ret;