thunderbolt: Add receiver lane margining support for retimers

Retimers support lane margining as well so make this available through
debugfs in the same way as we do for the USB4 ports. When this is
enabled we also expose retimers on the other side of the cable because
typically margining is implemented only on direction towards the cable.
However, for the retimers on the other side of the cable we do not allow
NVM upgrade to avoid confusing the existing userspace (the same retimer
may now appear twice with different name) and is probably not a good
idea anyway.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 66 insertions, 26 deletions

diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
index 87b2c91a4656..c2a735421609 100644
--- a/drivers/thunderbolt/debugfs.c
+++ b/drivers/thunderbolt/debugfs.c
@@ -380,6 +380,9 @@ out_rpm_put:
 /**
  * struct tb_margining - Lane margining support
  * @port: USB4 port through which the margining operations are run
+ * @target: Sideband target
+ * @index: Retimer index if taget is %USB4_SB_TARGET_RETIMER
+ * @dev: Pointer to the device that is the target (USB4 port or retimer)
  * @caps: Port lane margining capabilities
  * @results: Last lane margining results
  * @lanes: %0, %1 or %7 (all)
@@ -397,6 +400,9 @@ out_rpm_put:
  */
 struct tb_margining {
 	struct tb_port *port;
+	enum usb4_sb_target target;
+	u8 index;
+	struct device *dev;
 	u32 caps[2];
 	u32 results[2];
 	unsigned int lanes;
@@ -736,6 +742,7 @@ static int margining_run_write(void *data, u64 val)
 {
 	struct tb_margining *margining = data;
 	struct tb_port *port = margining->port;
+	struct device *dev = margining->dev;
 	struct tb_switch *sw = port->sw;
 	struct tb_switch *down_sw;
 	struct tb *tb = sw->tb;
@@ -744,7 +751,7 @@ static int margining_run_write(void *data, u64 val)
 	if (val != 1)
 		return -EINVAL;
 
-	pm_runtime_get_sync(&sw->dev);
+	pm_runtime_get_sync(dev);
 
 	if (mutex_lock_interruptible(&tb->lock)) {
 		ret = -ERESTARTSYS;
@@ -772,24 +779,29 @@ static int margining_run_write(void *data, u64 val)
 	}
 
 	if (margining->software) {
-		tb_port_dbg(port, "running software %s lane margining for lanes %u\n",
-			    margining->time ? "time" : "voltage", margining->lanes);
-		ret = usb4_port_sw_margin(port, USB4_SB_TARGET_ROUTER, 0,
+		tb_port_dbg(port,
+			    "running software %s lane margining for %s lanes %u\n",
+			    margining->time ? "time" : "voltage", dev_name(dev),
+			    margining->lanes);
+		ret = usb4_port_sw_margin(port, margining->target, margining->index,
 					  margining->lanes, margining->time,
 					  margining->right_high,
 					  USB4_MARGIN_SW_COUNTER_CLEAR);
 		if (ret)
 			goto out_clx;
 
-		ret = usb4_port_sw_margin_errors(port, USB4_SB_TARGET_ROUTER, 0,
+		ret = usb4_port_sw_margin_errors(port, margining->target,
+						 margining->index,
 						 &margining->results[0]);
 	} else {
-		tb_port_dbg(port, "running hardware %s lane margining for lanes %u\n",
-			    margining->time ? "time" : "voltage", margining->lanes);
+		tb_port_dbg(port,
+			    "running hardware %s lane margining for %s lanes %u\n",
+			    margining->time ? "time" : "voltage", dev_name(dev),
+			    margining->lanes);
 		/* Clear the results */
 		margining->results[0] = 0;
 		margining->results[1] = 0;
-		ret = usb4_port_hw_margin(port, USB4_SB_TARGET_ROUTER, 0,
+		ret = usb4_port_hw_margin(port, margining->target, margining->index,
 					  margining->lanes, margining->ber_level,
 					  margining->time, margining->right_high,
 					  margining->results);
@@ -801,8 +813,8 @@ out_clx:
 out_unlock:
 	mutex_unlock(&tb->lock);
 out_rpm_put:
-	pm_runtime_mark_last_busy(&sw->dev);
-	pm_runtime_put_autosuspend(&sw->dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 
 	return ret;
 }
@@ -1044,33 +1056,29 @@ static int margining_margin_show(struct seq_file *s, void *not_used)
 }
 DEBUGFS_ATTR_RW(margining_margin);
 
-static void margining_port_init(struct tb_port *port)
+static struct tb_margining *margining_alloc(struct tb_port *port,
+					    struct device *dev,
+					    enum usb4_sb_target target,
+					    u8 index, struct dentry *parent)
 {
 	struct tb_margining *margining;
-	struct dentry *dir, *parent;
-	struct usb4_port *usb4;
-	char dir_name[10];
+	struct dentry *dir;
 	unsigned int val;
 	int ret;
 
-	usb4 = port->usb4;
-	if (!usb4)
-		return;
-
-	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
-	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
-
 	margining = kzalloc(sizeof(*margining), GFP_KERNEL);
 	if (!margining)
-		return;
+		return NULL;
 
 	margining->port = port;
+	margining->target = target;
+	margining->index = index;
+	margining->dev = dev;
 
-	ret = usb4_port_margining_caps(port, USB4_SB_TARGET_ROUTER, 0,
-				       margining->caps);
+	ret = usb4_port_margining_caps(port, target, index, margining->caps);
 	if (ret) {
 		kfree(margining);
-		return;
+		return NULL;
 	}
 
 	/* Set the initial mode */
@@ -1124,8 +1132,22 @@ static void margining_port_init(struct tb_port *port)
 	     independent_time_margins(margining) == USB4_MARGIN_CAP_1_TIME_LR))
 		debugfs_create_file("margin", 0600, dir, margining,
 				    &margining_margin_fops);
+	return margining;
+}
 
-	usb4->margining = margining;
+static void margining_port_init(struct tb_port *port)
+{
+	struct dentry *parent;
+	char dir_name[10];
+
+	if (!port->usb4)
+		return;
+
+	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
+	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
+	port->usb4->margining = margining_alloc(port, &port->usb4->dev,
+						USB4_SB_TARGET_ROUTER, 0,
+						parent);
 }
 
 static void margining_port_remove(struct tb_port *port)
@@ -1199,11 +1221,27 @@ static void margining_xdomain_remove(struct tb_xdomain *xd)
 	downstream = tb_port_at(xd->route, parent_sw);
 	margining_port_remove(downstream);
 }
+
+static void margining_retimer_init(struct tb_retimer *rt, struct dentry *debugfs_dir)
+{
+	rt->margining = margining_alloc(rt->port, &rt->dev,
+					USB4_SB_TARGET_RETIMER, rt->index,
+					debugfs_dir);
+}
+
+static void margining_retimer_remove(struct tb_retimer *rt)
+{
+	kfree(rt->margining);
+	rt->margining = NULL;
+}
 #else
 static inline void margining_switch_init(struct tb_switch *sw) { }
 static inline void margining_switch_remove(struct tb_switch *sw) { }
 static inline void margining_xdomain_init(struct tb_xdomain *xd) { }
 static inline void margining_xdomain_remove(struct tb_xdomain *xd) { }
+static inline void margining_retimer_init(struct tb_retimer *rt,
+					  struct dentry *debugfs_dir) { }
+static inline void margining_retimer_remove(struct tb_retimer *rt) { }
 #endif
 
 static int port_clear_all_counters(struct tb_port *port)
@@ -1864,6 +1902,7 @@ void tb_retimer_debugfs_init(struct tb_retimer *rt)
 	debugfs_dir = debugfs_create_dir(dev_name(&rt->dev), tb_debugfs_root);
 	debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir, rt,
 			    &retimer_sb_regs_fops);
+	margining_retimer_init(rt, debugfs_dir);
 }
 
 /**
@@ -1875,6 +1914,7 @@ void tb_retimer_debugfs_init(struct tb_retimer *rt)
 void tb_retimer_debugfs_remove(struct tb_retimer *rt)
 {
 	debugfs_lookup_and_remove(dev_name(&rt->dev), tb_debugfs_root);
+	margining_retimer_remove(rt);
 }
 
 void tb_debugfs_init(void)