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From: Gil Fine <gil.fine@linux.intel.com>
Date: Fri, 3 Mar 2023 00:17:24 +0200
Subject: [PATCH] thunderbolt: Add missing UNSET_INBOUND_SBTX for retimer
 access
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References: bsc#1012628
Patch-mainline: 6.2.9
Git-commit: cd0c1e582b055dea615001b8bd8eccaf6f69f7ce

commit cd0c1e582b055dea615001b8bd8eccaf6f69f7ce upstream.

According to USB4 retimer specification, the process of firmware update
sequence requires issuing a SET_INBOUND_SBTX port operation that later
shall be followed by UNSET_INBOUND_SBTX port operation. This last step
is not currently issued by the driver but it is necessary to make sure
the retimers are put back to passthrough mode even during enumeration.

If this step is missing the link may not come up properly after
soft-reboot for example.

For this reason issue UNSET_INBOUND_SBTX after SET_INBOUND_SBTX for
enumeration and also when the NVM upgrade is run.

Reported-by: Christian Schaubschläger <christian.schaubschlaeger@gmx.at>
Link: https://lore.kernel.org/linux-usb/b556f5ed-5ee8-9990-9910-afd60db93310@gmx.at/
Cc: stable@vger.kernel.org
Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/thunderbolt/retimer.c | 23 +++++++++++++++++++++--
 drivers/thunderbolt/sb_regs.h |  1 +
 drivers/thunderbolt/tb.h      |  1 +
 drivers/thunderbolt/usb4.c    | 14 ++++++++++++++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/retimer.c b/drivers/thunderbolt/retimer.c
index 56008eb9..9cc28197 100644
--- a/drivers/thunderbolt/retimer.c
+++ b/drivers/thunderbolt/retimer.c
@@ -187,6 +187,22 @@ static ssize_t nvm_authenticate_show(struct device *dev,
 	return ret;
 }
 
+static void tb_retimer_set_inbound_sbtx(struct tb_port *port)
+{
+	int i;
+
+	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
+		usb4_port_retimer_set_inbound_sbtx(port, i);
+}
+
+static void tb_retimer_unset_inbound_sbtx(struct tb_port *port)
+{
+	int i;
+
+	for (i = TB_MAX_RETIMER_INDEX; i >= 1; i--)
+		usb4_port_retimer_unset_inbound_sbtx(port, i);
+}
+
 static ssize_t nvm_authenticate_store(struct device *dev,
 	struct device_attribute *attr, const char *buf, size_t count)
 {
@@ -213,6 +229,7 @@ static ssize_t nvm_authenticate_store(struct device *dev,
 	rt->auth_status = 0;
 
 	if (val) {
+		tb_retimer_set_inbound_sbtx(rt->port);
 		if (val == AUTHENTICATE_ONLY) {
 			ret = tb_retimer_nvm_authenticate(rt, true);
 		} else {
@@ -232,6 +249,7 @@ static ssize_t nvm_authenticate_store(struct device *dev,
 	}
 
 exit_unlock:
+	tb_retimer_unset_inbound_sbtx(rt->port);
 	mutex_unlock(&rt->tb->lock);
 exit_rpm:
 	pm_runtime_mark_last_busy(&rt->dev);
@@ -440,8 +458,7 @@ int tb_retimer_scan(struct tb_port *port, bool add)
 	 * Enable sideband channel for each retimer. We can do this
 	 * regardless whether there is device connected or not.
 	 */
-	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
-		usb4_port_retimer_set_inbound_sbtx(port, i);
+	tb_retimer_set_inbound_sbtx(port);
 
 	/*
 	 * Before doing anything else, read the authentication status.
@@ -464,6 +481,8 @@ int tb_retimer_scan(struct tb_port *port, bool add)
 			break;
 	}
 
+	tb_retimer_unset_inbound_sbtx(port);
+
 	if (!last_idx)
 		return 0;
 
diff --git a/drivers/thunderbolt/sb_regs.h b/drivers/thunderbolt/sb_regs.h
index 5185cf3e..f37a4320 100644
--- a/drivers/thunderbolt/sb_regs.h
+++ b/drivers/thunderbolt/sb_regs.h
@@ -20,6 +20,7 @@ enum usb4_sb_opcode {
 	USB4_SB_OPCODE_ROUTER_OFFLINE = 0x4e45534c,		/* "LSEN" */
 	USB4_SB_OPCODE_ENUMERATE_RETIMERS = 0x4d554e45,		/* "ENUM" */
 	USB4_SB_OPCODE_SET_INBOUND_SBTX = 0x5055534c,		/* "LSUP" */
+	USB4_SB_OPCODE_UNSET_INBOUND_SBTX = 0x50555355,		/* "USUP" */
 	USB4_SB_OPCODE_QUERY_LAST_RETIMER = 0x5453414c,		/* "LAST" */
 	USB4_SB_OPCODE_GET_NVM_SECTOR_SIZE = 0x53534e47,	/* "GNSS" */
 	USB4_SB_OPCODE_NVM_SET_OFFSET = 0x53504f42,		/* "BOPS" */
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 206759ad..e11d973a 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1220,6 +1220,7 @@ int usb4_port_sw_margin(struct tb_port *port, unsigned int lanes, bool timing,
 int usb4_port_sw_margin_errors(struct tb_port *port, u32 *errors);
 
 int usb4_port_retimer_set_inbound_sbtx(struct tb_port *port, u8 index);
+int usb4_port_retimer_unset_inbound_sbtx(struct tb_port *port, u8 index);
 int usb4_port_retimer_read(struct tb_port *port, u8 index, u8 reg, void *buf,
 			   u8 size);
 int usb4_port_retimer_write(struct tb_port *port, u8 index, u8 reg,
diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index ed1622ec..d5cd219e 100644
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -1578,6 +1578,20 @@ int usb4_port_retimer_set_inbound_sbtx(struct tb_port *port, u8 index)
 				    500);
 }
 
+/**
+ * usb4_port_retimer_unset_inbound_sbtx() - Disable sideband channel transactions
+ * @port: USB4 port
+ * @index: Retimer index
+ *
+ * Disables sideband channel transations on SBTX. The reverse of
+ * usb4_port_retimer_set_inbound_sbtx().
+ */
+int usb4_port_retimer_unset_inbound_sbtx(struct tb_port *port, u8 index)
+{
+	return usb4_port_retimer_op(port, index,
+				    USB4_SB_OPCODE_UNSET_INBOUND_SBTX, 500);
+}
+
 /**
  * usb4_port_retimer_read() - Read from retimer sideband registers
  * @port: USB4 port
-- 
2.35.3