[PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Alan Borzeszkowski]

Hello everyone,

This patch series introduces the creation of symlinks between
Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
primary goal is to provide users with clear visibility into which USB4
port is connected via a specific Type-C port. This provides the same
functionality that is already present in Chromebooks.

Alan Borzeszkowski (3):
  thunderbolt: Expose usb4_port_index() to other modules
  thunderbolt: Add Thunderbolt/USB4 <-> USB3 match function
  usb: typec: Connect Type-C port with associated USB4 port

 drivers/thunderbolt/tb.h        |  1 +
 drivers/thunderbolt/usb4.c      | 14 +++++++--
 drivers/thunderbolt/usb4_port.c | 56 ++++++++++++++++++++++++++++-----
 drivers/usb/typec/port-mapper.c | 23 ++++++++++++--
 include/linux/thunderbolt.h     | 18 +++++++++++
 5 files changed, 99 insertions(+), 13 deletions(-)


base-commit: 306a14d03f47fa152c7e47be544d8d582d387a20
-- 
2.43.0

[PATCH 1/3] thunderbolt: Expose usb4_port_index() to other modules

[Alan Borzeszkowski]

Make usb4_port_index() available to other files in the driver, rename
and add function documentation.

Signed-off-by: Alan Borzeszkowski <alan.borzeszkowski@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/thunderbolt/tb.h   |  1 +
 drivers/thunderbolt/usb4.c | 14 +++++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index da2d7c1f165b..82d39eb68cd0 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1481,6 +1481,7 @@ static inline struct usb4_port *tb_to_usb4_port_device(struct device *dev)
 struct usb4_port *usb4_port_device_add(struct tb_port *port);
 void usb4_port_device_remove(struct usb4_port *usb4);
 int usb4_port_device_resume(struct usb4_port *usb4);
+int usb4_port_index(const struct tb_switch *sw, const struct tb_port *port);
 
 static inline bool usb4_port_device_is_offline(const struct usb4_port *usb4)
 {
diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index 1b740d7fc7da..901ff57ad596 100644
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -935,7 +935,15 @@ int usb4_switch_dealloc_dp_resource(struct tb_switch *sw, struct tb_port *in)
 	return status ? -EIO : 0;
 }
 
-static int usb4_port_idx(const struct tb_switch *sw, const struct tb_port *port)
+/**
+ * usb4_port_index() - Finds matching USB4 port index
+ * @sw: USB4 router
+ * @port: USB4 protocol or lane adapter
+ *
+ * Finds matching USB4 port index (starting from %0) that given @port goes
+ * through.
+ */
+int usb4_port_index(const struct tb_switch *sw, const struct tb_port *port)
 {
 	struct tb_port *p;
 	int usb4_idx = 0;
@@ -969,7 +977,7 @@ static int usb4_port_idx(const struct tb_switch *sw, const struct tb_port *port)
 struct tb_port *usb4_switch_map_pcie_down(struct tb_switch *sw,
 					  const struct tb_port *port)
 {
-	int usb4_idx = usb4_port_idx(sw, port);
+	int usb4_idx = usb4_port_index(sw, port);
 	struct tb_port *p;
 	int pcie_idx = 0;
 
@@ -1000,7 +1008,7 @@ struct tb_port *usb4_switch_map_pcie_down(struct tb_switch *sw,
 struct tb_port *usb4_switch_map_usb3_down(struct tb_switch *sw,
 					  const struct tb_port *port)
 {
-	int usb4_idx = usb4_port_idx(sw, port);
+	int usb4_idx = usb4_port_index(sw, port);
 	struct tb_port *p;
 	int usb_idx = 0;
 
-- 
2.43.0

[PATCH 2/3] thunderbolt: Add Thunderbolt/USB4 <-> USB3 match function

[Alan Borzeszkowski]

This function checks whether given USB4 port device matches with USB3.x
port device, using ACPI _DSD property.

It is designed to be used by component framework to match
USB4 ports with Type-C ports they are connected to.

Also, added USB4 config stub in case mapping function is not reachable.

Signed-off-by: Alan Borzeszkowski <alan.borzeszkowski@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/thunderbolt/usb4_port.c | 56 ++++++++++++++++++++++++++++-----
 include/linux/thunderbolt.h     | 18 +++++++++++
 2 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/drivers/thunderbolt/usb4_port.c b/drivers/thunderbolt/usb4_port.c
index 5150879888ca..852a45fcd19d 100644
--- a/drivers/thunderbolt/usb4_port.c
+++ b/drivers/thunderbolt/usb4_port.c
@@ -105,6 +105,49 @@ static void usb4_port_online(struct usb4_port *usb4)
 	tb_acpi_power_off_retimers(port);
 }
 
+/**
+ * usb4_usb3_port_match() - Matches USB4 port device with USB 3.x port device
+ * @usb4_port_dev: USB4 port device
+ * @usb3_port_fwnode: USB 3.x port firmware node
+ *
+ * Checks if USB 3.x port @usb3_port_fwnode is tunneled through USB4 port @usb4_port_dev.
+ * Returns true if match is found, false otherwise.
+ *
+ * Function is designed to be used with component framework (component_match_add).
+ */
+bool usb4_usb3_port_match(struct device *usb4_port_dev,
+			  const struct fwnode_handle *usb3_port_fwnode)
+{
+	struct fwnode_handle *nhi_fwnode __free(fwnode_handle) = NULL;
+	struct usb4_port *usb4;
+	struct tb_switch *sw;
+	struct tb_nhi *nhi;
+	u8 usb4_port_num;
+	struct tb *tb;
+
+	usb4 = tb_to_usb4_port_device(usb4_port_dev);
+	if (!usb4)
+		return false;
+
+	sw = usb4->port->sw;
+	tb = sw->tb;
+	nhi = tb->nhi;
+
+	nhi_fwnode = fwnode_find_reference(usb3_port_fwnode, "usb4-host-interface", 0);
+	if (IS_ERR(nhi_fwnode))
+		return false;
+
+	/* Check if USB3 fwnode references same NHI where USB4 port resides */
+	if (!device_match_fwnode(&nhi->pdev->dev, nhi_fwnode))
+		return false;
+
+	if (fwnode_property_read_u8(usb3_port_fwnode, "usb4-port-number", &usb4_port_num))
+		return false;
+
+	return usb4_port_index(sw, usb4->port) == usb4_port_num;
+}
+EXPORT_SYMBOL_GPL(usb4_usb3_port_match);
+
 static ssize_t offline_show(struct device *dev,
 	struct device_attribute *attr, char *buf)
 {
@@ -276,12 +319,10 @@ struct usb4_port *usb4_port_device_add(struct tb_port *port)
 		return ERR_PTR(ret);
 	}
 
-	if (dev_fwnode(&usb4->dev)) {
-		ret = component_add(&usb4->dev, &connector_ops);
-		if (ret) {
-			dev_err(&usb4->dev, "failed to add component\n");
-			device_unregister(&usb4->dev);
-		}
+	ret = component_add(&usb4->dev, &connector_ops);
+	if (ret) {
+		dev_err(&usb4->dev, "failed to add component\n");
+		device_unregister(&usb4->dev);
 	}
 
 	if (!tb_is_upstream_port(port))
@@ -306,8 +347,7 @@ struct usb4_port *usb4_port_device_add(struct tb_port *port)
  */
 void usb4_port_device_remove(struct usb4_port *usb4)
 {
-	if (dev_fwnode(&usb4->dev))
-		component_del(&usb4->dev, &connector_ops);
+	component_del(&usb4->dev, &connector_ops);
 	device_unregister(&usb4->dev);
 }
 
diff --git a/include/linux/thunderbolt.h b/include/linux/thunderbolt.h
index 7d902d8c054b..75247486616b 100644
--- a/include/linux/thunderbolt.h
+++ b/include/linux/thunderbolt.h
@@ -11,6 +11,13 @@
 #ifndef THUNDERBOLT_H_
 #define THUNDERBOLT_H_
 
+#include <linux/types.h>
+
+struct fwnode_handle;
+struct device;
+
+#if IS_REACHABLE(CONFIG_USB4)
+
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/list.h>
@@ -674,4 +681,15 @@ static inline struct device *tb_ring_dma_device(struct tb_ring *ring)
 	return &ring->nhi->pdev->dev;
 }
 
+bool usb4_usb3_port_match(struct device *usb4_port_dev,
+			  const struct fwnode_handle *usb3_port_fwnode);
+
+#else /* CONFIG_USB4 */
+static inline bool usb4_usb3_port_match(struct device *usb4_port_dev,
+					const struct fwnode_handle *usb3_port_fwnode)
+{
+	return false;
+}
+#endif /* CONFIG_USB4 */
+
 #endif /* THUNDERBOLT_H_ */
-- 
2.43.0

[PATCH 3/3] usb: typec: Connect Type-C port with associated USB4 port

[Alan Borzeszkowski]

If USB3.x device references USB4 host interface, USB4 port can be
connected with appropriate Type-C port. By using component framework,
and in turn by creating symlinks, userspace can benefit from having
Thunderbolt/USB4 connection to Type-C ports.

Note: This change introduces dependency on Thunderbolt driver as it's
required to properly map USB4 port to Type-C port.

Signed-off-by: Alan Borzeszkowski <alan.borzeszkowski@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/port-mapper.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/port-mapper.c b/drivers/usb/typec/port-mapper.c
index d42da5720a25..cdbb7c11d714 100644
--- a/drivers/usb/typec/port-mapper.c
+++ b/drivers/usb/typec/port-mapper.c
@@ -8,6 +8,7 @@
 
 #include <linux/acpi.h>
 #include <linux/component.h>
+#include <linux/thunderbolt.h>
 #include <linux/usb.h>
 
 #include "class.h"
@@ -36,6 +37,11 @@ struct each_port_arg {
 	struct component_match *match;
 };
 
+static int usb4_port_compare(struct device *dev, void *fwnode)
+{
+	return usb4_usb3_port_match(dev, fwnode);
+}
+
 static int typec_port_compare(struct device *dev, void *fwnode)
 {
 	return device_match_fwnode(dev, fwnode);
@@ -51,9 +57,22 @@ static int typec_port_match(struct device *dev, void *data)
 	if (con_adev == adev)
 		return 0;
 
-	if (con_adev->pld_crc == adev->pld_crc)
+	if (con_adev->pld_crc == adev->pld_crc)	{
+		struct fwnode_handle *adev_fwnode = acpi_fwnode_handle(adev);
+
 		component_match_add(&arg->port->dev, &arg->match, typec_port_compare,
-				    acpi_fwnode_handle(adev));
+				    adev_fwnode);
+
+		/*
+		 * If dev is USB 3.x port, it may have reference to the
+		 * USB4 host interface in which case we can also link the
+		 * Type-C port with the USB4 port.
+		 */
+		if (fwnode_property_present(adev_fwnode, "usb4-host-interface"))
+			component_match_add(&arg->port->dev, &arg->match,
+					    usb4_port_compare, adev_fwnode);
+	}
+
 	return 0;
 }
 
-- 
2.43.0

Re: [PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Greg KH]

On Mon, Apr 14, 2025 at 07:55:51PM +0200, Alan Borzeszkowski wrote:
> Hello everyone,
> 
> This patch series introduces the creation of symlinks between
> Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
> primary goal is to provide users with clear visibility into which USB4
> port is connected via a specific Type-C port. This provides the same
> functionality that is already present in Chromebooks.

"mapping" in what way?  sysfs links?  If so, care to add
Documentation/ABI/ updates?

thanks,

greg k-h

Re: [PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Heikki Krogerus]

Hi Greg,

On Mon, Apr 14, 2025 at 09:03:42PM +0200, Greg KH wrote:
> On Mon, Apr 14, 2025 at 07:55:51PM +0200, Alan Borzeszkowski wrote:
> > Hello everyone,
> > 
> > This patch series introduces the creation of symlinks between
> > Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
> > primary goal is to provide users with clear visibility into which USB4
> > port is connected via a specific Type-C port. This provides the same
> > functionality that is already present in Chromebooks.
> 
> "mapping" in what way?  sysfs links?  If so, care to add
> Documentation/ABI/ updates?

It is already there:
https://docs.kernel.org/admin-guide/abi-testing.html#abi-sys-bus-thunderbolt-devices-usb4-portx-connector

The link is already created on Cromebooks like Alan explained, because
there each USB4/TBT port has a device node in the ACPI tables with the
appropriate _PLD (Physical Location of Device), but on systems
targeted primarily for Windows, that is not the case. There ports do
not have device nodes, so we can't make the link based on _PLD.

This series makes that same link by taking advantage of the
"usb4-host-interface" _DSD device property [1] that we always have on
those Windows platforms. That same device property that we also use in
drivers/usb/code/usb-acpi.c, and probable some other places too.

[1] https://www.usb.org/sites/default/files/D1T2-2%20-%20USB4%20on%20Windows.pdf

thanks,

-- 
heikki

Re: [PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Greg KH]

On Tue, Apr 15, 2025 at 12:32:11PM +0300, Heikki Krogerus wrote:
> Hi Greg,
> 
> On Mon, Apr 14, 2025 at 09:03:42PM +0200, Greg KH wrote:
> > On Mon, Apr 14, 2025 at 07:55:51PM +0200, Alan Borzeszkowski wrote:
> > > Hello everyone,
> > > 
> > > This patch series introduces the creation of symlinks between
> > > Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
> > > primary goal is to provide users with clear visibility into which USB4
> > > port is connected via a specific Type-C port. This provides the same
> > > functionality that is already present in Chromebooks.
> > 
> > "mapping" in what way?  sysfs links?  If so, care to add
> > Documentation/ABI/ updates?
> 
> It is already there:
> https://docs.kernel.org/admin-guide/abi-testing.html#abi-sys-bus-thunderbolt-devices-usb4-portx-connector
> 
> The link is already created on Cromebooks like Alan explained, because
> there each USB4/TBT port has a device node in the ACPI tables with the
> appropriate _PLD (Physical Location of Device), but on systems
> targeted primarily for Windows, that is not the case. There ports do
> not have device nodes, so we can't make the link based on _PLD.
> 
> This series makes that same link by taking advantage of the
> "usb4-host-interface" _DSD device property [1] that we always have on
> those Windows platforms. That same device property that we also use in
> drivers/usb/code/usb-acpi.c, and probable some other places too.
> 
> [1] https://www.usb.org/sites/default/files/D1T2-2%20-%20USB4%20on%20Windows.pdf

Thanks for the information, sorry I had missed that it was already
there.

greg k-h

Re: [PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Greg KH]

On Mon, Apr 14, 2025 at 07:55:51PM +0200, Alan Borzeszkowski wrote:
> Hello everyone,
> 
> This patch series introduces the creation of symlinks between
> Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
> primary goal is to provide users with clear visibility into which USB4
> port is connected via a specific Type-C port. This provides the same
> functionality that is already present in Chromebooks.
> 
> Alan Borzeszkowski (3):
>   thunderbolt: Expose usb4_port_index() to other modules
>   thunderbolt: Add Thunderbolt/USB4 <-> USB3 match function
>   usb: typec: Connect Type-C port with associated USB4 port
> 
>  drivers/thunderbolt/tb.h        |  1 +
>  drivers/thunderbolt/usb4.c      | 14 +++++++--
>  drivers/thunderbolt/usb4_port.c | 56 ++++++++++++++++++++++++++++-----
>  drivers/usb/typec/port-mapper.c | 23 ++++++++++++--
>  include/linux/thunderbolt.h     | 18 +++++++++++
>  5 files changed, 99 insertions(+), 13 deletions(-)
> 
> 
> base-commit: 306a14d03f47fa152c7e47be544d8d582d387a20
> -- 
> 2.43.0
> 
> 

I'm guessing that these will come through the thunderbolt tree to me?

Re: [PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Mika Westerberg]

On Tue, Apr 15, 2025 at 02:22:35PM +0200, Greg KH wrote:
> On Mon, Apr 14, 2025 at 07:55:51PM +0200, Alan Borzeszkowski wrote:
> > Hello everyone,
> > 
> > This patch series introduces the creation of symlinks between
> > Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
> > primary goal is to provide users with clear visibility into which USB4
> > port is connected via a specific Type-C port. This provides the same
> > functionality that is already present in Chromebooks.
> > 
> > Alan Borzeszkowski (3):
> >   thunderbolt: Expose usb4_port_index() to other modules
> >   thunderbolt: Add Thunderbolt/USB4 <-> USB3 match function
> >   usb: typec: Connect Type-C port with associated USB4 port
> > 
> >  drivers/thunderbolt/tb.h        |  1 +
> >  drivers/thunderbolt/usb4.c      | 14 +++++++--
> >  drivers/thunderbolt/usb4_port.c | 56 ++++++++++++++++++++++++++++-----
> >  drivers/usb/typec/port-mapper.c | 23 ++++++++++++--
> >  include/linux/thunderbolt.h     | 18 +++++++++++
> >  5 files changed, 99 insertions(+), 13 deletions(-)
> > 
> > 
> > base-commit: 306a14d03f47fa152c7e47be544d8d582d387a20
> > -- 
> > 2.43.0
> > 
> > 
> 
> I'm guessing that these will come through the thunderbolt tree to me?

Yes, I will pick them up and send to you with the rest of the v6.16 stuff.

Re: [PATCH 0/3] Introduce Thunderbolt/USB4 <-> USB Type-C port mapping

[Mika Westerberg]

On Mon, Apr 14, 2025 at 07:55:51PM +0200, Alan Borzeszkowski wrote:
> Hello everyone,
> 
> This patch series introduces the creation of symlinks between
> Thunderbolt/USB4 ports and their corresponding USB Type-C ports. The
> primary goal is to provide users with clear visibility into which USB4
> port is connected via a specific Type-C port. This provides the same
> functionality that is already present in Chromebooks.
> 
> Alan Borzeszkowski (3):
>   thunderbolt: Expose usb4_port_index() to other modules
>   thunderbolt: Add Thunderbolt/USB4 <-> USB3 match function
>   usb: typec: Connect Type-C port with associated USB4 port

All applied to thunderbolt.git/next, thanks!