[PATCH 0/9] thunderbolt: Add debugfs support

[PATCH 0/9] thunderbolt: Add debugfs support

[Mika Westerberg]

Hi all,

This series adds debugfs support to the driver. This is useful when
debugging different hardware/software issues as the developer can dump
different config spaces of the router including adapter, path and counters
config spaces. Each connected router is exposed in debugfs under
thunderbolt directory, and the naming follows what we have in sysfs.

This also adds a capability to write certain registers but that needs to be
enabled through Kconfig option, not supposed to be enabled by distros (or
regular users).

The series is based on top of my "Power Management improvements" patches
which can be viewed in the below link:

  https://lore.kernel.org/linux-usb/20200819115905.59834-1-mika.westerberg@linux.intel.com/

Gil Fine (2):
  thunderbolt: Introduce tb_switch_is_tiger_lake()
  thunderbolt: Add debugfs interface

Mika Westerberg (7):
  thunderbolt: Move struct tb_cap_any to tb_regs.h
  thunderbolt: Introduce tb_port_next_cap()
  thunderbolt: Introduce tb_switch_next_cap()
  thunderbolt: Introduce tb_port_is_nhi()
  thunderbolt: Check for Intel vendor ID when identifying controller
  thunderbolt: Introduce tb_switch_is_ice_lake()
  thunderbolt: No need to warn in TB_CFG_ERROR_INVALID_CONFIG_SPACE

 drivers/thunderbolt/Kconfig   |  10 +
 drivers/thunderbolt/Makefile  |   1 +
 drivers/thunderbolt/cap.c     | 126 ++++--
 drivers/thunderbolt/ctl.c     |   5 +-
 drivers/thunderbolt/debugfs.c | 700 ++++++++++++++++++++++++++++++++++
 drivers/thunderbolt/domain.c  |  13 +-
 drivers/thunderbolt/switch.c  |   5 +-
 drivers/thunderbolt/tb.h      | 109 ++++--
 drivers/thunderbolt/tb_regs.h |  18 +-
 9 files changed, 909 insertions(+), 78 deletions(-)
 create mode 100644 drivers/thunderbolt/debugfs.c

-- 
2.28.0

[PATCH 1/9] thunderbolt: Move struct tb_cap_any to tb_regs.h

[Mika Westerberg]

This structure will be needed by the debugfs implementation so make it
available outside of cap.c.

While there add kernel-doc comments to the structure.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/cap.c     |  8 --------
 drivers/thunderbolt/tb_regs.h | 14 ++++++++++++++
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c
index 19db6cdc5b70..1582e4ebac56 100644
--- a/drivers/thunderbolt/cap.c
+++ b/drivers/thunderbolt/cap.c
@@ -15,14 +15,6 @@
 #define VSE_CAP_OFFSET_MAX	0xffff
 #define TMU_ACCESS_EN		BIT(20)
 
-struct tb_cap_any {
-	union {
-		struct tb_cap_basic basic;
-		struct tb_cap_extended_short extended_short;
-		struct tb_cap_extended_long extended_long;
-	};
-} __packed;
-
 static int tb_port_enable_tmu(struct tb_port *port, bool enable)
 {
 	struct tb_switch *sw = port->sw;
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 0431e415e3bc..c33751be0f56 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -93,6 +93,20 @@ struct tb_cap_extended_long {
 	u16 length;
 } __packed;
 
+/**
+ * struct tb_cap_any - Structure capable of hold every capability
+ * @basic: Basic capability
+ * @extended_short: Vendor specific capability
+ * @extended_long: Vendor specific extended capability
+ */
+struct tb_cap_any {
+	union {
+		struct tb_cap_basic basic;
+		struct tb_cap_extended_short extended_short;
+		struct tb_cap_extended_long extended_long;
+	};
+} __packed;
+
 /* capabilities */
 
 struct tb_cap_link_controller {
-- 
2.28.0

[PATCH 2/9] thunderbolt: Introduce tb_port_next_cap()

[Mika Westerberg]

This function is useful for walking port config space (adapter)
capability lists. Convert the tb_port_find_cap() to use this as well.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/cap.c | 35 +++++++++++++++++++++++++++++++----
 drivers/thunderbolt/tb.h  |  1 +
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c
index 1582e4ebac56..c45b3a488412 100644
--- a/drivers/thunderbolt/cap.c
+++ b/drivers/thunderbolt/cap.c
@@ -59,23 +59,50 @@ static void tb_port_dummy_read(struct tb_port *port)
 	}
 }
 
+/**
+ * tb_port_next_cap() - Return next capability in the linked list
+ * @port: Port to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Returns dword offset of the next capability in port config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_port_next_cap(struct tb_port *port, unsigned int offset)
+{
+	struct tb_cap_any header;
+	int ret;
+
+	if (!offset)
+		return port->config.first_cap_offset;
+
+	ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
+	if (ret)
+		return ret;
+
+	return header.basic.next;
+}
+
 static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
 {
-	u32 offset = 1;
+	int offset = 0;
 
 	do {
 		struct tb_cap_any header;
 		int ret;
 
+		offset = tb_port_next_cap(port, offset);
+		if (offset < 0)
+			return offset;
+
 		ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
 		if (ret)
 			return ret;
 
 		if (header.basic.cap == cap)
 			return offset;
-
-		offset = header.basic.next;
-	} while (offset);
+	} while (offset > 0);
 
 	return -ENOENT;
 }
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 7754c690addc..54e8fad78bee 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -823,6 +823,7 @@ int tb_port_get_link_speed(struct tb_port *port);
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec);
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap);
 int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap);
+int tb_port_next_cap(struct tb_port *port, unsigned int offset);
 bool tb_port_is_enabled(struct tb_port *port);
 
 bool tb_usb3_port_is_enabled(struct tb_port *port);
-- 
2.28.0

[PATCH 3/9] thunderbolt: Introduce tb_switch_next_cap()

[Mika Westerberg]

This is similar to tb_port_next_cap() but instead allows walking
capability list of a switch (router). Convert tb_switch_find_cap() and
tb_switch_find_vse_cap() to use this as well.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/cap.c | 83 +++++++++++++++++++++++++--------------
 drivers/thunderbolt/tb.h  |  1 +
 2 files changed, 54 insertions(+), 30 deletions(-)

diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c
index c45b3a488412..9af1b855e43b 100644
--- a/drivers/thunderbolt/cap.c
+++ b/drivers/thunderbolt/cap.c
@@ -132,6 +132,40 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
 	return ret;
 }
 
+/**
+ * tb_switch_next_cap() - Return next capability in the linked list
+ * @sw: Switch to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Finds dword offset of the next capability in router config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset)
+{
+	struct tb_cap_any header;
+	int ret;
+
+	if (!offset)
+		return sw->config.first_cap_offset;
+
+	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+	if (ret)
+		return ret;
+
+	if (header.basic.cap == TB_SWITCH_CAP_VSE) {
+		if (!header.extended_short.length)
+			ret = header.extended_long.next;
+		else
+			ret = header.extended_short.next;
+	} else {
+		ret = header.basic.next;
+	}
+
+	return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret;
+}
+
 /**
  * tb_switch_find_cap() - Find switch capability
  * @sw Switch to find the capability for
@@ -143,21 +177,23 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
  */
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
 {
-	int offset = sw->config.first_cap_offset;
+	int offset = 0;
 
-	while (offset > 0 && offset < CAP_OFFSET_MAX) {
+	do {
 		struct tb_cap_any header;
 		int ret;
 
+		offset = tb_switch_next_cap(sw, offset);
+		if (offset < 0)
+			return offset;
+
 		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
 		if (ret)
 			return ret;
 
 		if (header.basic.cap == cap)
 			return offset;
-
-		offset = header.basic.next;
-	}
+	} while (offset);
 
 	return -ENOENT;
 }
@@ -174,37 +210,24 @@ int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
  */
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
 {
-	struct tb_cap_any header;
-	int offset;
-
-	offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
-	if (offset < 0)
-		return offset;
+	int offset = 0;
 
-	while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
+	do {
+		struct tb_cap_any header;
 		int ret;
 
-		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+		offset = tb_switch_next_cap(sw, offset);
+		if (offset < 0)
+			return offset;
+
+		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
 		if (ret)
 			return ret;
 
-		/*
-		 * Extended vendor specific capabilities come in two
-		 * flavors: short and long. The latter is used when
-		 * offset is over 0xff.
-		 */
-		if (offset >= CAP_OFFSET_MAX) {
-			if (header.extended_long.vsec_id == vsec)
-				return offset;
-			offset = header.extended_long.next;
-		} else {
-			if (header.extended_short.vsec_id == vsec)
-				return offset;
-			if (!header.extended_short.length)
-				return -ENOENT;
-			offset = header.extended_short.next;
-		}
-	}
+		if (header.extended_short.cap == TB_SWITCH_CAP_VSE &&
+		    header.extended_short.vsec_id == vsec)
+			return offset;
+	} while (offset);
 
 	return -ENOENT;
 }
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 54e8fad78bee..a1d5de53a349 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -822,6 +822,7 @@ int tb_port_get_link_speed(struct tb_port *port);
 
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec);
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap);
+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset);
 int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap);
 int tb_port_next_cap(struct tb_port *port, unsigned int offset);
 bool tb_port_is_enabled(struct tb_port *port);
-- 
2.28.0

[PATCH 4/9] thunderbolt: Introduce tb_port_is_nhi()

[Mika Westerberg]

This is useful if one needs to check if adapter (port) is the host
interface (NHI). Make tb_port_alloc_hopid() take advantage of this.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/switch.c | 2 +-
 drivers/thunderbolt/tb.h     | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index f646bad88309..d7164843cf8b 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -789,7 +789,7 @@ static int tb_port_alloc_hopid(struct tb_port *port, bool in, int min_hopid,
 	 * NHI can use HopIDs 1-max for other adapters HopIDs 0-7 are
 	 * reserved.
 	 */
-	if (port->config.type != TB_TYPE_NHI && min_hopid < TB_PATH_MIN_HOPID)
+	if (!tb_port_is_nhi(port) && min_hopid < TB_PATH_MIN_HOPID)
 		min_hopid = TB_PATH_MIN_HOPID;
 
 	if (max_hopid < 0 || max_hopid > port_max_hopid)
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index a1d5de53a349..6aee18b4f53d 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -464,6 +464,11 @@ static inline bool tb_port_is_null(const struct tb_port *port)
 	return port && port->port && port->config.type == TB_TYPE_PORT;
 }
 
+static inline bool tb_port_is_nhi(const struct tb_port *port)
+{
+	return port && port->config.type == TB_TYPE_NHI;
+}
+
 static inline bool tb_port_is_pcie_down(const struct tb_port *port)
 {
 	return port && port->config.type == TB_TYPE_PCIE_DOWN;
-- 
2.28.0

[PATCH 5/9] thunderbolt: Check for Intel vendor ID when identifying controller

[Mika Westerberg]

With USB4 there will be other vendors so make sure the current checks
for different Intel controllers will not accidentally match those.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb.h | 64 ++++++++++++++++++++++------------------
 1 file changed, 35 insertions(+), 29 deletions(-)

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 6aee18b4f53d..664a861e8e9f 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -697,59 +697,65 @@ static inline struct tb_switch *tb_switch_parent(struct tb_switch *sw)
 
 static inline bool tb_switch_is_light_ridge(const struct tb_switch *sw)
 {
-	return sw->config.device_id == PCI_DEVICE_ID_INTEL_LIGHT_RIDGE;
+	return sw->config.vendor_id == PCI_VENDOR_ID_INTEL &&
+	       sw->config.device_id == PCI_DEVICE_ID_INTEL_LIGHT_RIDGE;
 }
 
 static inline bool tb_switch_is_eagle_ridge(const struct tb_switch *sw)
 {
-	return sw->config.device_id == PCI_DEVICE_ID_INTEL_EAGLE_RIDGE;
+	return sw->config.vendor_id == PCI_VENDOR_ID_INTEL &&
+	       sw->config.device_id == PCI_DEVICE_ID_INTEL_EAGLE_RIDGE;
 }
 
 static inline bool tb_switch_is_cactus_ridge(const struct tb_switch *sw)
 {
-	switch (sw->config.device_id) {
-	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_2C:
-	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C:
-		return true;
-	default:
-		return false;
+	if (sw->config.vendor_id == PCI_VENDOR_ID_INTEL) {
+		switch (sw->config.device_id) {
+		case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_2C:
+		case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C:
+			return true;
+		}
 	}
+	return false;
 }
 
 static inline bool tb_switch_is_falcon_ridge(const struct tb_switch *sw)
 {
-	switch (sw->config.device_id) {
-	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_BRIDGE:
-	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_BRIDGE:
-		return true;
-	default:
-		return false;
+	if (sw->config.vendor_id == PCI_VENDOR_ID_INTEL) {
+		switch (sw->config.device_id) {
+		case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_BRIDGE:
+		case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_BRIDGE:
+			return true;
+		}
 	}
+	return false;
 }
 
 static inline bool tb_switch_is_alpine_ridge(const struct tb_switch *sw)
 {
-	switch (sw->config.device_id) {
-	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_BRIDGE:
-	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_BRIDGE:
-	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_BRIDGE:
-	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_BRIDGE:
-		return true;
-	default:
-		return false;
+	if (sw->config.vendor_id == PCI_VENDOR_ID_INTEL) {
+		switch (sw->config.device_id) {
+		case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_BRIDGE:
+		case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_BRIDGE:
+		case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_BRIDGE:
+		case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_BRIDGE:
+			return true;
+		}
 	}
+	return false;
 }
 
 static inline bool tb_switch_is_titan_ridge(const struct tb_switch *sw)
 {
-	switch (sw->config.device_id) {
-	case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_2C_BRIDGE:
-	case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_4C_BRIDGE:
-	case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_DD_BRIDGE:
-		return true;
-	default:
-		return false;
+	if (sw->config.vendor_id == PCI_VENDOR_ID_INTEL) {
+		switch (sw->config.device_id) {
+		case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_2C_BRIDGE:
+		case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_4C_BRIDGE:
+		case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_DD_BRIDGE:
+			return true;
+		}
 	}
+	return false;
 }
 
 /**
-- 
2.28.0

[PATCH 6/9] thunderbolt: Introduce tb_switch_is_ice_lake()

[Mika Westerberg]

This is needed to differentiate Ice Lake from other controllers.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 664a861e8e9f..1d5ee4c0de1c 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -758,6 +758,18 @@ static inline bool tb_switch_is_titan_ridge(const struct tb_switch *sw)
 	return false;
 }
 
+static inline bool tb_switch_is_ice_lake(const struct tb_switch *sw)
+{
+	if (sw->config.vendor_id == PCI_VENDOR_ID_INTEL) {
+		switch (sw->config.device_id) {
+		case PCI_DEVICE_ID_INTEL_ICL_NHI0:
+		case PCI_DEVICE_ID_INTEL_ICL_NHI1:
+			return true;
+		}
+	}
+	return false;
+}
+
 /**
  * tb_switch_is_usb4() - Is the switch USB4 compliant
  * @sw: Switch to check
-- 
2.28.0

[PATCH 7/9] thunderbolt: Introduce tb_switch_is_tiger_lake()

[Mika Westerberg]

From: Gil Fine <gil.fine@intel.com>

This is needed to differentiate Tiger Lake from other controllers.

Signed-off-by: Gil Fine <gil.fine@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 1d5ee4c0de1c..3035258b3afa 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -770,6 +770,18 @@ static inline bool tb_switch_is_ice_lake(const struct tb_switch *sw)
 	return false;
 }
 
+static inline bool tb_switch_is_tiger_lake(const struct tb_switch *sw)
+{
+	if (sw->config.vendor_id == PCI_VENDOR_ID_INTEL) {
+		switch (sw->config.device_id) {
+		case PCI_DEVICE_ID_INTEL_TGL_NHI0:
+		case PCI_DEVICE_ID_INTEL_TGL_NHI1:
+			return true;
+		}
+	}
+	return false;
+}
+
 /**
  * tb_switch_is_usb4() - Is the switch USB4 compliant
  * @sw: Switch to check
-- 
2.28.0

[PATCH 8/9] thunderbolt: No need to warn in TB_CFG_ERROR_INVALID_CONFIG_SPACE

[Mika Westerberg]

This may be returned for example when accessing some of the vendor
specific capabilities. It is not fatal by any means so instead of WARN()
just log it as debug level. The caller gets error back anyway and is
expected to handle it accordingly.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/ctl.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c
index f77ceae5c7d7..38e5e296fe3f 100644
--- a/drivers/thunderbolt/ctl.c
+++ b/drivers/thunderbolt/ctl.c
@@ -266,9 +266,8 @@ static void tb_cfg_print_error(struct tb_ctl *ctl,
 		 * Invalid cfg_space/offset/length combination in
 		 * cfg_read/cfg_write.
 		 */
-		tb_ctl_WARN(ctl,
-			"CFG_ERROR(%llx:%x): Invalid config space or offset\n",
-			res->response_route, res->response_port);
+		tb_ctl_dbg(ctl, "%llx:%x: invalid config space or offset\n",
+			   res->response_route, res->response_port);
 		return;
 	case TB_CFG_ERROR_NO_SUCH_PORT:
 		/*
-- 
2.28.0

[PATCH 9/9] thunderbolt: Add debugfs interface

[Mika Westerberg]

From: Gil Fine <gil.fine@intel.com>

This adds debugfs interface that can be used for debugging possible
issues in hardware/software. It exposes router and adapter config spaces
through files like this:

  /sys/kernel/debug/thunderbolt/<DEVICE>/regs
  /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT1>/regs
  /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT1>/path
  /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT1>/counters
  /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT2>/regs
  /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT2>/path
  /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT2>/counters
  ...

The "regs" is either the router or port configuration space register
dump. The "path" is the port path configuration space and "counters" is
the optional counters configuration space.

These files contains one register per line so it should be easy to use
normal filtering tools to find the registers of interest if needed.

The router and adapter regs file becomes writable when
CONFIG_USB4_DEBUGFS_WRITE is enabled (which is not supposed to be done
in production systems) and in this case the developer can write "offset
value" lines there to modify the hardware directly. For convenience this
also supports the long format the read side produces (but ignores the
additional fields). The counters file can be written even when
CONFIG_USB4_DEBUGFS_WRITE is not enabled and it is only used to clear
the counter values.

Signed-off-by: Gil Fine <gil.fine@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/Kconfig   |  10 +
 drivers/thunderbolt/Makefile  |   1 +
 drivers/thunderbolt/debugfs.c | 700 ++++++++++++++++++++++++++++++++++
 drivers/thunderbolt/domain.c  |  13 +-
 drivers/thunderbolt/switch.c  |   3 +
 drivers/thunderbolt/tb.h      |  14 +
 drivers/thunderbolt/tb_regs.h |   4 +-
 7 files changed, 742 insertions(+), 3 deletions(-)
 create mode 100644 drivers/thunderbolt/debugfs.c

diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
index 354e61c0f2e5..2257c22f8ab3 100644
--- a/drivers/thunderbolt/Kconfig
+++ b/drivers/thunderbolt/Kconfig
@@ -16,6 +16,16 @@ menuconfig USB4
 	  To compile this driver a module, choose M here. The module will be
 	  called thunderbolt.
 
+config USB4_DEBUGFS_WRITE
+	bool "Enable write by debugfs to configuration spaces (DANGEROUS)"
+	depends on USB4
+	help
+	  Enables writing to device configuration registers through
+	  debugfs interface.
+
+	  Only enable this if you know what you are doing! Never enable
+	  this for production systems or distro kernels.
+
 config USB4_KUNIT_TEST
 	bool "KUnit tests"
 	depends on KUNIT=y
diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index 754a529aa132..61d5dff445b6 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -5,5 +5,6 @@ thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o us
 thunderbolt-objs += nvm.o retimer.o quirks.o
 
 thunderbolt-${CONFIG_ACPI} += acpi.o
+thunderbolt-$(CONFIG_DEBUG_FS) += debugfs.o
 
 obj-${CONFIG_USB4_KUNIT_TEST} += test.o
diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
new file mode 100644
index 000000000000..fdfe6e4afbfe
--- /dev/null
+++ b/drivers/thunderbolt/debugfs.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Debugfs interface
+ *
+ * Copyright (C) 2020, Intel Corporation
+ * Authors: Gil Fine <gil.fine@intel.com>
+ *	    Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/pm_runtime.h>
+
+#include "tb.h"
+
+#define PORT_CAP_PCIE_LEN	1
+#define PORT_CAP_POWER_LEN	2
+#define PORT_CAP_LANE_LEN	3
+#define PORT_CAP_USB3_LEN	5
+#define PORT_CAP_DP_LEN		8
+#define PORT_CAP_TMU_LEN	8
+#define PORT_CAP_BASIC_LEN	9
+#define PORT_CAP_USB4_LEN	20
+
+#define SWITCH_CAP_TMU_LEN	26
+#define SWITCH_CAP_BASIC_LEN	27
+
+#define PATH_LEN		2
+
+#define COUNTER_SET_LEN		3
+
+#define DEBUGFS_ATTR(__space, __write)					\
+static int __space ## _open(struct inode *inode, struct file *file)	\
+{									\
+	return single_open(file, __space ## _show, inode->i_private);	\
+}									\
+									\
+static const struct file_operations __space ## _fops = {		\
+	.owner = THIS_MODULE,						\
+	.open = __space ## _open,					\
+	.release = single_release,					\
+	.read  = seq_read,						\
+	.write = __write,						\
+	.llseek = seq_lseek,						\
+}
+
+#define DEBUGFS_ATTR_RO(__space)					\
+	DEBUGFS_ATTR(__space, NULL)
+
+#define DEBUGFS_ATTR_RW(__space)					\
+	DEBUGFS_ATTR(__space, __space ## _write)
+
+static struct dentry *tb_debugfs_root;
+
+static void *validate_and_copy_from_user(const void __user *user_buf,
+					 size_t *count)
+{
+	size_t nbytes;
+	void *buf;
+
+	if (!*count)
+		return ERR_PTR(-EINVAL);
+
+	if (!access_ok(user_buf, *count))
+		return ERR_PTR(-EFAULT);
+
+	buf = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	nbytes = min_t(size_t, *count, PAGE_SIZE);
+	if (copy_from_user(buf, user_buf, nbytes)) {
+		free_page((unsigned long)buf);
+		return ERR_PTR(-EFAULT);
+	}
+
+	*count = nbytes;
+	return buf;
+}
+
+static bool parse_line(char **line, u32 *offs, u32 *val, int short_fmt_len,
+		       int long_fmt_len)
+{
+	char *token;
+	u32 v[5];
+	int ret;
+
+	token = strsep(line, "\n");
+	if (!token)
+		return false;
+
+	/*
+	 * For Adapter/Router configuration space:
+	 * Short format is: offset value\n
+	 *		    v[0]   v[1]
+	 * Long format as produced from the read side:
+	 * offset relative_offset cap_id vs_cap_id value\n
+	 * v[0]   v[1]            v[2]   v[3]      v[4]
+	 *
+	 * For Counter configuration space:
+	 * Short format is: offset\n
+	 *		    v[0]
+	 * Long format as produced from the read side:
+	 * offset relative_offset counter_id value\n
+	 * v[0]   v[1]            v[2]       v[3]
+	 */
+	ret = sscanf(token, "%i %i %i %i %i", &v[0], &v[1], &v[2], &v[3], &v[4]);
+	/* In case of Counters, clear counter, "val" content is NA */
+	if (ret == short_fmt_len) {
+		*offs = v[0];
+		*val = v[short_fmt_len - 1];
+		return true;
+	} else if (ret == long_fmt_len) {
+		*offs = v[0];
+		*val = v[long_fmt_len - 1];
+		return true;
+	}
+
+	return false;
+}
+
+#if IS_ENABLED(CONFIG_USB4_DEBUGFS_WRITE)
+static ssize_t regs_write(struct tb_switch *sw, struct tb_port *port,
+			  const char __user *user_buf, size_t count,
+			  loff_t *ppos)
+{
+	struct tb *tb = sw->tb;
+	char *line, *buf;
+	u32 val, offset;
+	int ret = 0;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	/* User did hardware changes behind the driver's back */
+	add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+
+	line = buf;
+	while (parse_line(&line, &offset, &val, 2, 5)) {
+		if (port)
+			ret = tb_port_write(port, &val, TB_CFG_PORT, offset, 1);
+		else
+			ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, offset, 1);
+		if (ret)
+			break;
+	}
+
+	mutex_unlock(&tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+	free_page((unsigned long)buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t port_regs_write(struct file *file, const char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_port *port = s->private;
+
+	return regs_write(port->sw, port, user_buf, count, ppos);
+}
+
+static ssize_t switch_regs_write(struct file *file, const char __user *user_buf,
+				 size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_switch *sw = s->private;
+
+	return regs_write(sw, NULL, user_buf, count, ppos);
+}
+#define DEBUGFS_MODE		0600
+#else
+#define port_regs_write		NULL
+#define switch_regs_write	NULL
+#define DEBUGFS_MODE		0400
+#endif
+
+static int port_clear_all_counters(struct tb_port *port)
+{
+	u32 *buf;
+	int ret;
+
+	buf = kcalloc(COUNTER_SET_LEN * port->config.max_counters, sizeof(u32),
+		      GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = tb_port_write(port, buf, TB_CFG_COUNTERS, 0,
+			    COUNTER_SET_LEN * port->config.max_counters);
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t counters_write(struct file *file, const char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_port *port = s->private;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = port->sw->tb;
+	char *buf;
+	int ret;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	/* If written delimiter only, clear all counters in one shot */
+	if (buf[0] == '\n') {
+		ret = port_clear_all_counters(port);
+	} else  {
+		char *line = buf;
+		u32 val, offset;
+
+		while (parse_line(&line, &offset, &val, 1, 4)) {
+			ret = tb_port_write(port, &val, TB_CFG_COUNTERS,
+					    offset, 1);
+			if (ret)
+				break;
+		}
+	}
+
+	mutex_unlock(&tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+	free_page((unsigned long)buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static void cap_show(struct seq_file *s, struct tb_switch *sw,
+		     struct tb_port *port, unsigned int cap, u8 cap_id,
+		     u8 vsec_id, int length)
+{
+	int ret, offset = 0;
+
+	while (length > 0) {
+		int i, dwords = min(length, TB_MAX_CONFIG_RW_LENGTH);
+		u32 data[TB_MAX_CONFIG_RW_LENGTH];
+
+		if (port)
+			ret = tb_port_read(port, data, TB_CFG_PORT, cap + offset,
+					   dwords);
+		else
+			ret = tb_sw_read(sw, data, TB_CFG_SWITCH, cap + offset, dwords);
+		if (ret) {
+			seq_printf(s, "0x%04x <not accessible>\n",
+				   cap + offset);
+			if (dwords > 1)
+				seq_printf(s, "0x%04x ...\n", cap + offset + 1);
+			return;
+		}
+
+		for (i = 0; i < dwords; i++) {
+			seq_printf(s, "0x%04x %4d 0x%02x 0x%02x 0x%08x\n",
+				   cap + offset + i, offset + i,
+				   cap_id, vsec_id, data[i]);
+		}
+
+		length -= dwords;
+		offset += dwords;
+	}
+}
+
+static void port_cap_show(struct tb_port *port, struct seq_file *s,
+			  unsigned int cap)
+{
+	struct tb_cap_any header;
+	u8 vsec_id = 0;
+	size_t length;
+	int ret;
+
+	ret = tb_port_read(port, &header, TB_CFG_PORT, cap, 1);
+	if (ret) {
+		seq_printf(s, "0x%04x <capability read failed>\n", cap);
+		return;
+	}
+
+	switch (header.basic.cap) {
+	case TB_PORT_CAP_PHY:
+		length = PORT_CAP_LANE_LEN;
+		break;
+
+	case TB_PORT_CAP_TIME1:
+		length = PORT_CAP_TMU_LEN;
+		break;
+
+	case TB_PORT_CAP_POWER:
+		length = PORT_CAP_POWER_LEN;
+		break;
+
+	case TB_PORT_CAP_ADAP:
+		if (tb_port_is_pcie_down(port) || tb_port_is_pcie_up(port)) {
+			length = PORT_CAP_PCIE_LEN;
+		} else if (tb_port_is_dpin(port) || tb_port_is_dpout(port)) {
+			length = PORT_CAP_DP_LEN;
+		} else if (tb_port_is_usb3_down(port) ||
+			   tb_port_is_usb3_up(port)) {
+			length = PORT_CAP_USB3_LEN;
+		} else {
+			seq_printf(s, "0x%04x <unsupported capability 0x%02x>\n",
+				   cap, header.basic.cap);
+			return;
+		}
+		break;
+
+	case TB_PORT_CAP_VSE:
+		if (!header.extended_short.length) {
+			ret = tb_port_read(port, (u32 *)&header + 1, TB_CFG_PORT,
+					   cap + 1, 1);
+			if (ret) {
+				seq_printf(s, "0x%04x <capability read failed>\n",
+					   cap + 1);
+				return;
+			}
+			length = header.extended_long.length;
+			vsec_id = header.extended_short.vsec_id;
+		} else {
+			length = header.extended_short.length;
+			vsec_id = header.extended_short.vsec_id;
+			/*
+			 * Ice Lake and Tiger Lake do not implement the
+			 * full length of the capability, only first 32
+			 * dwords so hard-code it here.
+			 */
+			if (!vsec_id &&
+			    (tb_switch_is_ice_lake(port->sw) ||
+			     tb_switch_is_tiger_lake(port->sw)))
+				length = 32;
+		}
+		break;
+
+	case TB_PORT_CAP_USB4:
+		length = PORT_CAP_USB4_LEN;
+		break;
+
+	default:
+		seq_printf(s, "0x%04x <unsupported capability 0x%02x>\n",
+			   cap, header.basic.cap);
+		return;
+	}
+
+	cap_show(s, NULL, port, cap, header.basic.cap, vsec_id, length);
+}
+
+static void port_caps_show(struct tb_port *port, struct seq_file *s)
+{
+	int cap;
+
+	cap = tb_port_next_cap(port, 0);
+	while (cap > 0) {
+		port_cap_show(port, s, cap);
+		cap = tb_port_next_cap(port, cap);
+	}
+}
+
+static int port_basic_regs_show(struct tb_port *port, struct seq_file *s)
+{
+	u32 data[PORT_CAP_BASIC_LEN];
+	int ret, i;
+
+	ret = tb_port_read(port, data, TB_CFG_PORT, 0, ARRAY_SIZE(data));
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(data); i++)
+		seq_printf(s, "0x%04x %4d 0x00 0x00 0x%08x\n", i, i, data[i]);
+
+	return 0;
+}
+
+static int port_regs_show(struct seq_file *s, void *not_used)
+{
+	struct tb_port *port = s->private;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = sw->tb;
+	int ret;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	seq_puts(s, "# offset relative_offset cap_id vs_cap_id value\n");
+
+	ret = port_basic_regs_show(port, s);
+	if (ret)
+		goto out_unlock;
+
+	port_caps_show(port, s);
+
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(port_regs);
+
+static void switch_cap_show(struct tb_switch *sw, struct seq_file *s,
+			    unsigned int cap)
+{
+	struct tb_cap_any header;
+	int ret, length;
+	u8 vsec_id = 0;
+
+	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, cap, 1);
+	if (ret) {
+		seq_printf(s, "0x%04x <capability read failed>\n", cap);
+		return;
+	}
+
+	if (header.basic.cap == TB_SWITCH_CAP_VSE) {
+		if (!header.extended_short.length) {
+			ret = tb_sw_read(sw, (u32 *)&header + 1, TB_CFG_SWITCH,
+					 cap + 1, 1);
+			if (ret) {
+				seq_printf(s, "0x%04x <capability read failed>\n",
+					   cap + 1);
+				return;
+			}
+			length = header.extended_long.length;
+		} else {
+			length = header.extended_short.length;
+		}
+		vsec_id = header.extended_short.vsec_id;
+	} else {
+		if (header.basic.cap == TB_SWITCH_CAP_TMU) {
+			length = SWITCH_CAP_TMU_LEN;
+		} else  {
+			seq_printf(s, "0x%04x <unknown capability 0x%02x>\n",
+				   cap, header.basic.cap);
+			return;
+		}
+	}
+
+	cap_show(s, sw, NULL, cap, header.basic.cap, vsec_id, length);
+}
+
+static void switch_caps_show(struct tb_switch *sw, struct seq_file *s)
+{
+	int cap;
+
+	cap = tb_switch_next_cap(sw, 0);
+	while (cap > 0) {
+		switch_cap_show(sw, s, cap);
+		cap = tb_switch_next_cap(sw, cap);
+	}
+}
+
+static int switch_basic_regs_show(struct tb_switch *sw, struct seq_file *s)
+{
+	u32 data[SWITCH_CAP_BASIC_LEN];
+	size_t dwords;
+	int ret, i;
+
+	/* Only USB4 has the additional registers */
+	if (tb_switch_is_usb4(sw))
+		dwords = ARRAY_SIZE(data);
+	else
+		dwords = 7;
+
+	ret = tb_sw_read(sw, data, TB_CFG_SWITCH, 0, dwords);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < dwords; i++)
+		seq_printf(s, "0x%04x %4d 0x00 0x00 0x%08x\n", i, i, data[i]);
+
+	return 0;
+}
+
+static int switch_regs_show(struct seq_file *s, void *not_used)
+{
+	struct tb_switch *sw = s->private;
+	struct tb *tb = sw->tb;
+	int ret;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	seq_puts(s, "# offset relative_offset cap_id vs_cap_id value\n");
+
+	ret = switch_basic_regs_show(sw, s);
+	if (ret)
+		goto out_unlock;
+
+	switch_caps_show(sw, s);
+
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(switch_regs);
+
+static int path_show_one(struct tb_port *port, struct seq_file *s, int hopid)
+{
+	u32 data[PATH_LEN];
+	int ret, i;
+
+	ret = tb_port_read(port, data, TB_CFG_HOPS, hopid * PATH_LEN,
+			   ARRAY_SIZE(data));
+	if (ret) {
+		seq_printf(s, "0x%04x <not accessible>\n", hopid * PATH_LEN);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(data); i++) {
+		seq_printf(s, "0x%04x %4d 0x%02x 0x%08x\n",
+			   hopid * PATH_LEN + i, i, hopid, data[i]);
+	}
+
+	return 0;
+}
+
+static int path_show(struct seq_file *s, void *not_used)
+{
+	struct tb_port *port = s->private;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = sw->tb;
+	int start, i, ret = 0;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	seq_puts(s, "# offset relative_offset in_hop_id value\n");
+
+	/* NHI and lane adapters have entry for path 0 */
+	if (tb_port_is_null(port) || tb_port_is_nhi(port)) {
+		ret = path_show_one(port, s, 0);
+		if (ret)
+			goto out_unlock;
+	}
+
+	start = tb_port_is_nhi(port) ? 1 : TB_PATH_MIN_HOPID;
+
+	for (i = start; i <= port->config.max_in_hop_id; i++) {
+		ret = path_show_one(port, s, i);
+		if (ret)
+			break;
+	}
+
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RO(path);
+
+static int counter_set_regs_show(struct tb_port *port, struct seq_file *s,
+				 int counter)
+{
+	u32 data[COUNTER_SET_LEN];
+	int ret, i;
+
+	ret = tb_port_read(port, data, TB_CFG_COUNTERS,
+			   counter * COUNTER_SET_LEN, ARRAY_SIZE(data));
+	if (ret) {
+		seq_printf(s, "0x%04x <not accessible>\n",
+			   counter * COUNTER_SET_LEN);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(data); i++) {
+		seq_printf(s, "0x%04x %4d 0x%02x 0x%08x\n",
+			   counter * COUNTER_SET_LEN + i, i, counter, data[i]);
+	}
+
+	return 0;
+}
+
+static int counters_show(struct seq_file *s, void *not_used)
+{
+	struct tb_port *port = s->private;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = sw->tb;
+	int i, ret = 0;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	seq_puts(s, "# offset relative_offset counter_id value\n");
+
+	for (i = 0; i < port->config.max_counters; i++) {
+		ret = counter_set_regs_show(port, s, i);
+		if (ret)
+			break;
+	}
+
+	mutex_unlock(&tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(counters);
+
+/**
+ * tb_switch_debugfs_init() - Add debugfs entries for router
+ * @sw: Pointer to the router
+ *
+ * Adds debugfs directories and files for given router.
+ */
+void tb_switch_debugfs_init(struct tb_switch *sw)
+{
+	struct dentry *debugfs_dir;
+	struct tb_port *port;
+
+	debugfs_dir = debugfs_create_dir(dev_name(&sw->dev), tb_debugfs_root);
+	sw->debugfs_dir = debugfs_dir;
+	debugfs_create_file("regs", DEBUGFS_MODE, debugfs_dir, sw,
+			    &switch_regs_fops);
+
+	tb_switch_for_each_port(sw, port) {
+		struct dentry *debugfs_dir;
+		char dir_name[10];
+
+		if (port->disabled)
+			continue;
+		if (port->config.type == TB_TYPE_INACTIVE)
+			continue;
+
+		snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
+		debugfs_dir = debugfs_create_dir(dir_name, sw->debugfs_dir);
+		debugfs_create_file("regs", DEBUGFS_MODE, debugfs_dir,
+				    port, &port_regs_fops);
+		debugfs_create_file("path", 0400, debugfs_dir, port,
+				    &path_fops);
+		if (port->config.counters_support)
+			debugfs_create_file("counters", 0600, debugfs_dir, port,
+					    &counters_fops);
+	}
+}
+
+/**
+ * tb_switch_debugfs_remove() - Remove all router debugfs entries
+ * @sw: Pointer to the router
+ *
+ * Removes all previously added debugfs entries under this router.
+ */
+void tb_switch_debugfs_remove(struct tb_switch *sw)
+{
+	debugfs_remove_recursive(sw->debugfs_dir);
+}
+
+void tb_debugfs_init(void)
+{
+	tb_debugfs_root = debugfs_create_dir("thunderbolt", NULL);
+}
+
+void tb_debugfs_exit(void)
+{
+	debugfs_remove_recursive(tb_debugfs_root);
+}
diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c
index 7ca6a2b34ddc..753f98c25a3b 100644
--- a/drivers/thunderbolt/domain.c
+++ b/drivers/thunderbolt/domain.c
@@ -800,12 +800,20 @@ int tb_domain_init(void)
 {
 	int ret;
 
+	tb_debugfs_init();
 	ret = tb_xdomain_init();
 	if (ret)
-		return ret;
+		goto err_debugfs;
 	ret = bus_register(&tb_bus_type);
 	if (ret)
-		tb_xdomain_exit();
+		goto err_xdomain;
+
+	return 0;
+
+err_xdomain:
+	tb_xdomain_exit();
+err_debugfs:
+	tb_debugfs_exit();
 
 	return ret;
 }
@@ -816,4 +824,5 @@ void tb_domain_exit(void)
 	ida_destroy(&tb_domain_ida);
 	tb_nvm_exit();
 	tb_xdomain_exit();
+	tb_debugfs_exit();
 }
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index d7164843cf8b..6b246945429f 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -2517,6 +2517,7 @@ int tb_switch_add(struct tb_switch *sw)
 		pm_request_autosuspend(&sw->dev);
 	}
 
+	tb_switch_debugfs_init(sw);
 	return 0;
 }
 
@@ -2532,6 +2533,8 @@ void tb_switch_remove(struct tb_switch *sw)
 {
 	struct tb_port *port;
 
+	tb_switch_debugfs_remove(sw);
+
 	if (sw->rpm) {
 		pm_runtime_get_sync(&sw->dev);
 		pm_runtime_disable(&sw->dev);
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 3035258b3afa..450f9cf16005 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -125,6 +125,7 @@ struct tb_switch_tmu {
  * @rpm: The switch supports runtime PM
  * @authorized: Whether the switch is authorized by user or policy
  * @security_level: Switch supported security level
+ * @debugfs_dir: Pointer to the debugfs structure
  * @key: Contains the key used to challenge the device or %NULL if not
  *	 supported. Size of the key is %TB_SWITCH_KEY_SIZE.
  * @connection_id: Connection ID used with ICM messaging
@@ -166,6 +167,7 @@ struct tb_switch {
 	bool rpm;
 	unsigned int authorized;
 	enum tb_security_level security_level;
+	struct dentry *debugfs_dir;
 	u8 *key;
 	u8 connection_id;
 	u8 connection_key;
@@ -1010,4 +1012,16 @@ void tb_acpi_add_links(struct tb_nhi *nhi);
 static inline void tb_acpi_add_links(struct tb_nhi *nhi) { }
 #endif
 
+#ifdef CONFIG_DEBUG_FS
+void tb_debugfs_init(void);
+void tb_debugfs_exit(void);
+void tb_switch_debugfs_init(struct tb_switch *sw);
+void tb_switch_debugfs_remove(struct tb_switch *sw);
+#else
+static inline void tb_debugfs_init(void) { }
+static inline void tb_debugfs_exit(void) { }
+static inline void tb_switch_debugfs_init(struct tb_switch *sw) { }
+static inline void tb_switch_debugfs_remove(struct tb_switch *sw) { }
+#endif
+
 #endif
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index c33751be0f56..e7d9529822fa 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -39,6 +39,7 @@ enum tb_switch_vse_cap {
 
 enum tb_port_cap {
 	TB_PORT_CAP_PHY			= 0x01,
+	TB_PORT_CAP_POWER		= 0x02,
 	TB_PORT_CAP_TIME1		= 0x03,
 	TB_PORT_CAP_ADAP		= 0x04,
 	TB_PORT_CAP_VSE			= 0x05,
@@ -252,7 +253,8 @@ struct tb_regs_port_header {
 	/* DWORD 1 */
 	u32 first_cap_offset:8;
 	u32 max_counters:11;
-	u32 __unknown1:5;
+	u32 counters_support:1;
+	u32 __unknown1:4;
 	u32 revision:8;
 	/* DWORD 2 */
 	enum tb_port_type type:24;
-- 
2.28.0

Re: [PATCH 9/9] thunderbolt: Add debugfs interface

[Greg Kroah-Hartman]

On Wed, Aug 26, 2020 at 02:07:36PM +0300, Mika Westerberg wrote:
> From: Gil Fine <gil.fine@intel.com>
> 
> This adds debugfs interface that can be used for debugging possible
> issues in hardware/software. It exposes router and adapter config spaces
> through files like this:
> 
>   /sys/kernel/debug/thunderbolt/<DEVICE>/regs
>   /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT1>/regs
>   /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT1>/path
>   /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT1>/counters
>   /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT2>/regs
>   /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT2>/path
>   /sys/kernel/debug/thunderbolt/<DEVICE>/<PORT2>/counters
>   ...
> 
> The "regs" is either the router or port configuration space register
> dump. The "path" is the port path configuration space and "counters" is
> the optional counters configuration space.
> 
> These files contains one register per line so it should be easy to use
> normal filtering tools to find the registers of interest if needed.
> 
> The router and adapter regs file becomes writable when
> CONFIG_USB4_DEBUGFS_WRITE is enabled (which is not supposed to be done
> in production systems) and in this case the developer can write "offset
> value" lines there to modify the hardware directly. For convenience this
> also supports the long format the read side produces (but ignores the
> additional fields). The counters file can be written even when
> CONFIG_USB4_DEBUGFS_WRITE is not enabled and it is only used to clear
> the counter values.
> 
> Signed-off-by: Gil Fine <gil.fine@intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
>  drivers/thunderbolt/Kconfig   |  10 +
>  drivers/thunderbolt/Makefile  |   1 +
>  drivers/thunderbolt/debugfs.c | 700 ++++++++++++++++++++++++++++++++++
>  drivers/thunderbolt/domain.c  |  13 +-
>  drivers/thunderbolt/switch.c  |   3 +
>  drivers/thunderbolt/tb.h      |  14 +
>  drivers/thunderbolt/tb_regs.h |   4 +-
>  7 files changed, 742 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/thunderbolt/debugfs.c
> 
> diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
> index 354e61c0f2e5..2257c22f8ab3 100644
> --- a/drivers/thunderbolt/Kconfig
> +++ b/drivers/thunderbolt/Kconfig
> @@ -16,6 +16,16 @@ menuconfig USB4
>  	  To compile this driver a module, choose M here. The module will be
>  	  called thunderbolt.
>  
> +config USB4_DEBUGFS_WRITE
> +	bool "Enable write by debugfs to configuration spaces (DANGEROUS)"
> +	depends on USB4
> +	help
> +	  Enables writing to device configuration registers through
> +	  debugfs interface.
> +
> +	  Only enable this if you know what you are doing! Never enable
> +	  this for production systems or distro kernels.
> +
>  config USB4_KUNIT_TEST
>  	bool "KUnit tests"
>  	depends on KUNIT=y
> diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
> index 754a529aa132..61d5dff445b6 100644
> --- a/drivers/thunderbolt/Makefile
> +++ b/drivers/thunderbolt/Makefile
> @@ -5,5 +5,6 @@ thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o us
>  thunderbolt-objs += nvm.o retimer.o quirks.o
>  
>  thunderbolt-${CONFIG_ACPI} += acpi.o
> +thunderbolt-$(CONFIG_DEBUG_FS) += debugfs.o
>  
>  obj-${CONFIG_USB4_KUNIT_TEST} += test.o
> diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
> new file mode 100644
> index 000000000000..fdfe6e4afbfe
> --- /dev/null
> +++ b/drivers/thunderbolt/debugfs.c
> @@ -0,0 +1,700 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Debugfs interface
> + *
> + * Copyright (C) 2020, Intel Corporation
> + * Authors: Gil Fine <gil.fine@intel.com>
> + *	    Mika Westerberg <mika.westerberg@linux.intel.com>
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "tb.h"
> +
> +#define PORT_CAP_PCIE_LEN	1
> +#define PORT_CAP_POWER_LEN	2
> +#define PORT_CAP_LANE_LEN	3
> +#define PORT_CAP_USB3_LEN	5
> +#define PORT_CAP_DP_LEN		8
> +#define PORT_CAP_TMU_LEN	8
> +#define PORT_CAP_BASIC_LEN	9
> +#define PORT_CAP_USB4_LEN	20
> +
> +#define SWITCH_CAP_TMU_LEN	26
> +#define SWITCH_CAP_BASIC_LEN	27
> +
> +#define PATH_LEN		2
> +
> +#define COUNTER_SET_LEN		3
> +
> +#define DEBUGFS_ATTR(__space, __write)					\
> +static int __space ## _open(struct inode *inode, struct file *file)	\
> +{									\
> +	return single_open(file, __space ## _show, inode->i_private);	\
> +}									\
> +									\
> +static const struct file_operations __space ## _fops = {		\
> +	.owner = THIS_MODULE,						\
> +	.open = __space ## _open,					\
> +	.release = single_release,					\
> +	.read  = seq_read,						\
> +	.write = __write,						\
> +	.llseek = seq_lseek,						\
> +}
> +
> +#define DEBUGFS_ATTR_RO(__space)					\
> +	DEBUGFS_ATTR(__space, NULL)
> +
> +#define DEBUGFS_ATTR_RW(__space)					\
> +	DEBUGFS_ATTR(__space, __space ## _write)

We do have DEFINE_SIMPLE_ATTRIBUTE() and DEFINE_DEBUGFS_ATTRIBUTE, do
those work here instead of your custom macro?

Other than that, this series looks fine to me:

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH 9/9] thunderbolt: Add debugfs interface

[Mika Westerberg]

Hi Greg,

On Wed, Aug 26, 2020 at 01:22:46PM +0200, Greg Kroah-Hartman wrote:
> > +#define DEBUGFS_ATTR(__space, __write)					\
> > +static int __space ## _open(struct inode *inode, struct file *file)	\
> > +{									\
> > +	return single_open(file, __space ## _show, inode->i_private);	\
> > +}									\
> > +									\
> > +static const struct file_operations __space ## _fops = {		\
> > +	.owner = THIS_MODULE,						\
> > +	.open = __space ## _open,					\
> > +	.release = single_release,					\
> > +	.read  = seq_read,						\
> > +	.write = __write,						\
> > +	.llseek = seq_lseek,						\
> > +}
> > +
> > +#define DEBUGFS_ATTR_RO(__space)					\
> > +	DEBUGFS_ATTR(__space, NULL)
> > +
> > +#define DEBUGFS_ATTR_RW(__space)					\
> > +	DEBUGFS_ATTR(__space, __space ## _write)
> 
> We do have DEFINE_SIMPLE_ATTRIBUTE() and DEFINE_DEBUGFS_ATTRIBUTE, do
> those work here instead of your custom macro?

Unfortunately they do not work as they want u64 for the write side but
we actually need to parse (offset, value) pairs here when write is
enabled.

> Other than that, this series looks fine to me:
> 
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Thanks!

[PATCH v2 3/9] thunderbolt: Introduce tb_switch_next_cap()

[Mika Westerberg]

This is similar to tb_port_next_cap() but instead allows walking
capability list of a switch (router). Convert tb_switch_find_cap() and
tb_switch_find_vse_cap() to use this as well.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Hi all,

Just sending this one as the rest of the series is unchanged. I noticed
when testing with older devices, the Port Ridge controller (found on Apple
Thunderbolt ethernet/firewire dongles) does not terminate the router
capability list correctly so this version checks for the two supported
capability IDs and terminates the walk if an unknown ID is found.

Also added Greg's tag.

 drivers/thunderbolt/cap.c | 93 ++++++++++++++++++++++++++-------------
 drivers/thunderbolt/tb.h  |  1 +
 2 files changed, 64 insertions(+), 30 deletions(-)

diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c
index c45b3a488412..6f571e912cf2 100644
--- a/drivers/thunderbolt/cap.c
+++ b/drivers/thunderbolt/cap.c
@@ -132,6 +132,50 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
 	return ret;
 }
 
+/**
+ * tb_switch_next_cap() - Return next capability in the linked list
+ * @sw: Switch to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Finds dword offset of the next capability in router config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset)
+{
+	struct tb_cap_any header;
+	int ret;
+
+	if (!offset)
+		return sw->config.first_cap_offset;
+
+	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+	if (ret)
+		return ret;
+
+	switch (header.basic.cap) {
+	case TB_SWITCH_CAP_TMU:
+		ret = header.basic.next;
+		break;
+
+	case TB_SWITCH_CAP_VSE:
+		if (!header.extended_short.length)
+			ret = header.extended_long.next;
+		else
+			ret = header.extended_short.next;
+		break;
+
+	default:
+		tb_sw_dbg(sw, "unknown capability %#x at %#x\n",
+			  header.basic.cap, offset);
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret;
+}
+
 /**
  * tb_switch_find_cap() - Find switch capability
  * @sw Switch to find the capability for
@@ -143,21 +187,23 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
  */
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
 {
-	int offset = sw->config.first_cap_offset;
+	int offset = 0;
 
-	while (offset > 0 && offset < CAP_OFFSET_MAX) {
+	do {
 		struct tb_cap_any header;
 		int ret;
 
+		offset = tb_switch_next_cap(sw, offset);
+		if (offset < 0)
+			return offset;
+
 		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
 		if (ret)
 			return ret;
 
 		if (header.basic.cap == cap)
 			return offset;
-
-		offset = header.basic.next;
-	}
+	} while (offset);
 
 	return -ENOENT;
 }
@@ -174,37 +220,24 @@ int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
  */
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
 {
-	struct tb_cap_any header;
-	int offset;
-
-	offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
-	if (offset < 0)
-		return offset;
+	int offset = 0;
 
-	while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
+	do {
+		struct tb_cap_any header;
 		int ret;
 
-		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+		offset = tb_switch_next_cap(sw, offset);
+		if (offset < 0)
+			return offset;
+
+		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
 		if (ret)
 			return ret;
 
-		/*
-		 * Extended vendor specific capabilities come in two
-		 * flavors: short and long. The latter is used when
-		 * offset is over 0xff.
-		 */
-		if (offset >= CAP_OFFSET_MAX) {
-			if (header.extended_long.vsec_id == vsec)
-				return offset;
-			offset = header.extended_long.next;
-		} else {
-			if (header.extended_short.vsec_id == vsec)
-				return offset;
-			if (!header.extended_short.length)
-				return -ENOENT;
-			offset = header.extended_short.next;
-		}
-	}
+		if (header.extended_short.cap == TB_SWITCH_CAP_VSE &&
+		    header.extended_short.vsec_id == vsec)
+			return offset;
+	} while (offset);
 
 	return -ENOENT;
 }
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 786c313ce97c..cbd18cad9bcd 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -828,6 +828,7 @@ int tb_port_get_link_speed(struct tb_port *port);
 
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec);
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap);
+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset);
 int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap);
 int tb_port_next_cap(struct tb_port *port, unsigned int offset);
 bool tb_port_is_enabled(struct tb_port *port);
-- 
2.28.0

Re: [PATCH 0/9] thunderbolt: Add debugfs support

[Mika Westerberg]

On Wed, Aug 26, 2020 at 02:07:27PM +0300, Mika Westerberg wrote:
> Hi all,
> 
> This series adds debugfs support to the driver. This is useful when
> debugging different hardware/software issues as the developer can dump
> different config spaces of the router including adapter, path and counters
> config spaces. Each connected router is exposed in debugfs under
> thunderbolt directory, and the naming follows what we have in sysfs.
> 
> This also adds a capability to write certain registers but that needs to be
> enabled through Kconfig option, not supposed to be enabled by distros (or
> regular users).
> 
> The series is based on top of my "Power Management improvements" patches
> which can be viewed in the below link:
> 
>   https://lore.kernel.org/linux-usb/20200819115905.59834-1-mika.westerberg@linux.intel.com/
> 
> Gil Fine (2):
>   thunderbolt: Introduce tb_switch_is_tiger_lake()
>   thunderbolt: Add debugfs interface
> 
> Mika Westerberg (7):
>   thunderbolt: Move struct tb_cap_any to tb_regs.h
>   thunderbolt: Introduce tb_port_next_cap()
>   thunderbolt: Introduce tb_switch_next_cap()
>   thunderbolt: Introduce tb_port_is_nhi()
>   thunderbolt: Check for Intel vendor ID when identifying controller
>   thunderbolt: Introduce tb_switch_is_ice_lake()
>   thunderbolt: No need to warn in TB_CFG_ERROR_INVALID_CONFIG_SPACE

All applied to thunderbolt.git/next.