[PATCH 0/2] DWC3 link tunneling state reporting

[PATCH 0/2] DWC3 link tunneling state reporting

[Konrad Dybcio]

Currently, retrieving the tunneled/native state of a running port is
only possible on Intel XHCI hosts. This series extends that to CIO-
capable DWC31 controllers (see [1]).

Note that this patchset only results in the correct udev->tunnel_mode
value being assigned. Creating the device links (which requires this
information) between the USB4 router and the USB3 controller does not
currently take place on DT-based platforms, but that will be amended
in a follow-up patchset.

Tested on a Qualcomm X1E80100 CRD board, with a (currently) out-of-tree
set of drivers.

[1] I'm not entirely sure about the DWC version range (particularly
    wrt DWC32 and newer), so I limited it to a reasonable subset. I'll
    happily amend that.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
Konrad Dybcio (2):
      usb: host: xhci: Allow non-Intel usb_link_tunnel_mode reporting
      usb: dwc3: Notify XHCI core of tunneled status

 drivers/usb/dwc3/core.c      | 12 ++++++++++++
 drivers/usb/dwc3/core.h      | 18 ++++++++++++++++++
 drivers/usb/dwc3/host.c      | 12 ++++++++++++
 drivers/usb/host/xhci-hub.c  |  4 ++--
 drivers/usb/host/xhci-plat.c |  2 ++
 drivers/usb/host/xhci-plat.h |  1 +
 drivers/usb/host/xhci.c      |  6 +++++-
 drivers/usb/host/xhci.h      |  5 ++++-
 8 files changed, 56 insertions(+), 4 deletions(-)
---
base-commit: b9303e6bff706758c167af686b5315ad00233bf8
change-id: 20260504-topic-dwc3_tunneling_state-50588c0e1ae3

Best regards,
--  
Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

[PATCH 1/2] usb: host: xhci: Allow non-Intel usb_link_tunnel_mode reporting

[Konrad Dybcio]

From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

The Thunderbolt framework relies on the USB core to create device links
for tunneled ports, so that the USB3 controller is only kept
runtime-resumed for the duration of the tunneling.

Currently, retrieving that information is only possibe on Intel XHCI
hosts, through a vendor-specific capability. Extend xhci-plat to allow
plumbing a custom one.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
 drivers/usb/host/xhci-hub.c  | 4 ++--
 drivers/usb/host/xhci-plat.c | 2 ++
 drivers/usb/host/xhci-plat.h | 1 +
 drivers/usb/host/xhci.c      | 6 +++++-
 drivers/usb/host/xhci.h      | 5 ++++-
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index bacd0ddd0d09..09e5da912066 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -750,7 +750,7 @@ static int xhci_exit_test_mode(struct xhci_hcd *xhci)
 }
 
 /**
- * xhci_port_is_tunneled() - Check if USB3 connection is tunneled over USB4
+ * xhci_port_tunnel_mode() - Check if USB3 connection is tunneled over USB4
  * @xhci: xhci host controller
  * @port: USB3 port to be checked.
  *
@@ -764,7 +764,7 @@ static int xhci_exit_test_mode(struct xhci_hcd *xhci)
  * detecting USB3 over USB4 tunnels. USB_LINK_NATIVE or USB_LINK_TUNNELED
  * otherwise.
  */
-enum usb_link_tunnel_mode xhci_port_is_tunneled(struct xhci_hcd *xhci,
+enum usb_link_tunnel_mode xhci_port_tunnel_mode(struct xhci_hcd *xhci,
 						struct xhci_port *port)
 {
 	struct usb_hcd *hcd;
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 074d9c731639..dbaca694baa2 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -244,6 +244,8 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev, const s
 		priv = hcd_to_xhci_priv(hcd);
 		/* Just copy data for now */
 		*priv = *priv_match;
+
+		xhci->tunnel_mode = priv->tunnel_mode;
 	}
 
 	device_set_wakeup_capable(&pdev->dev, true);
diff --git a/drivers/usb/host/xhci-plat.h b/drivers/usb/host/xhci-plat.h
index 00751d851831..c5042766a486 100644
--- a/drivers/usb/host/xhci-plat.h
+++ b/drivers/usb/host/xhci-plat.h
@@ -22,6 +22,7 @@ struct xhci_plat_priv {
 	int (*suspend_quirk)(struct usb_hcd *);
 	int (*resume_quirk)(struct usb_hcd *);
 	int (*post_resume_quirk)(struct usb_hcd *);
+	enum usb_link_tunnel_mode (*tunnel_mode)(struct usb_hcd *hcd, int portnum);
 };
 
 #define hcd_to_xhci_priv(h) ((struct xhci_plat_priv *)hcd_to_xhci(h)->priv)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index a54f5b57f205..90a6751b5c69 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4754,7 +4754,11 @@ static int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
 	if (hcd->speed >= HCD_USB3 && !udev->parent->parent) {
 		port = xhci->usb3_rhub.ports[udev->portnum - 1];
 
-		udev->tunnel_mode = xhci_port_is_tunneled(xhci, port);
+		if (xhci->tunnel_mode)
+			udev->tunnel_mode = xhci->tunnel_mode(hcd, port->hcd_portnum);
+		else
+			udev->tunnel_mode = xhci_port_tunnel_mode(xhci, port);
+
 		if (udev->tunnel_mode == USB_LINK_UNKNOWN)
 			dev_dbg(&udev->dev, "link tunnel state unknown\n");
 		else if (udev->tunnel_mode == USB_LINK_TUNNELED)
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index aeecd301f207..59cc5797d5d2 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1672,6 +1672,9 @@ struct xhci_hcd {
 	struct list_head	regset_list;
 
 	void			*dbc;
+
+	enum usb_link_tunnel_mode (*tunnel_mode)(struct usb_hcd *hcd, int portnum);
+
 	/* platform-specific data -- must come last */
 	unsigned long		priv[] __aligned(sizeof(s64));
 };
@@ -1977,7 +1980,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
 int xhci_hub_status_data(struct usb_hcd *hcd, char *buf);
 int xhci_find_raw_port_number(struct usb_hcd *hcd, int port1);
 struct xhci_hub *xhci_get_rhub(struct usb_hcd *hcd);
-enum usb_link_tunnel_mode xhci_port_is_tunneled(struct xhci_hcd *xhci,
+enum usb_link_tunnel_mode xhci_port_tunnel_mode(struct xhci_hcd *xhci,
 						struct xhci_port *port);
 void xhci_hc_died(struct xhci_hcd *xhci);
 

-- 
2.54.0

[PATCH 2/2] usb: dwc3: Notify XHCI core of tunneled status

[Konrad Dybcio]

From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

The Thunderbolt framework relies on the USB core to create device links
for tunneled ports, so that the USB3 controller is only kept
runtime-resumed for the duration of the tunneling. This depends on
first knowing whether a connection is tunneled or native.

Add the logic to handle that for DWC3 controllers.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
 drivers/usb/dwc3/core.c | 12 ++++++++++++
 drivers/usb/dwc3/core.h | 18 ++++++++++++++++++
 drivers/usb/dwc3/host.c | 12 ++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 65213896de99..7cec4911e278 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -162,6 +162,18 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode, bool ignore_susphy)
 }
 EXPORT_SYMBOL_GPL(dwc3_set_prtcap);
 
+enum usb_link_tunnel_mode dwc3_link_tunnel_mode(struct dwc3 *dwc, u8 port)
+{
+	/* Prior versions had no CIO support */
+	if (!DWC3_VER_IS_WITHIN(DWC31, 191A, ANY))
+		return USB_LINK_NATIVE;
+
+	if (dwc3_readl(dwc, DWC3_CIOCTRL(port)) & DWC3_CIOCTRL_CIO_EN)
+		return USB_LINK_TUNNELED;
+
+	return USB_LINK_NATIVE;
+}
+
 static void __dwc3_set_mode(struct work_struct *work)
 {
 	struct dwc3 *dwc = work_to_dwc(work);
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index e0dee9d28740..9594829de6c7 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -179,6 +179,11 @@
 #define DWC3_OEVTEN		0xcc0C
 #define DWC3_OSTS		0xcc10
 
+/* CIO regs */
+#define DWC3_CIO_BASE(n)	(0xcd20 + ((n) * 0x30))
+#define DWC3_CIOCTRL(n)		(DWC3_CIO_BASE(n) + 0x00)
+#define DWC3_CIOCTRL_CIO_EN	BIT(0)
+
 #define DWC3_LLUCTL(n)		(0xd024 + ((n) * 0x80))
 
 /* Bit fields */
@@ -1309,6 +1314,7 @@ struct dwc3 {
 #define DWC31_REVISION_170A	0x3137302a
 #define DWC31_REVISION_180A	0x3138302a
 #define DWC31_REVISION_190A	0x3139302a
+#define DWC31_REVISION_191A	0x3139312a
 #define DWC31_REVISION_200A	0x3230302a
 
 #define DWC32_REVISION_ANY	0x0
@@ -1653,11 +1659,23 @@ static inline void dwc3_pre_run_stop(struct dwc3 *dwc, bool is_on)
 #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
 int dwc3_host_init(struct dwc3 *dwc);
 void dwc3_host_exit(struct dwc3 *dwc);
+
+/**
+ * dwc3_link_tunnel_mode - Check whether the link is tunneled over TBT/USB4
+ * @dwc: Pointer to DWC3 controller context
+ * @port: 0-based port index
+ *
+ * Returns: USB_LINK_TUNNELED if tunneled, USB_LINK_NATIVE if not, or
+ *          when the controller does not have USB4 capabilities.
+ */
+enum usb_link_tunnel_mode dwc3_link_tunnel_mode(struct dwc3 *dwc, u8 port);
 #else
 static inline int dwc3_host_init(struct dwc3 *dwc)
 { return 0; }
 static inline void dwc3_host_exit(struct dwc3 *dwc)
 { }
+static inline enum usb_link_tunnel_mode dwc3_link_tunnel_mode(struct dwc3 *dwc, u8 port)
+{ return USB_LINK_UNKNOWN; }
 #endif
 
 #if IS_ENABLED(CONFIG_USB_DWC3_GADGET) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index 96b588bd08cd..eb03b079696e 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -77,8 +77,20 @@ static void dwc3_xhci_plat_start(struct usb_hcd *hcd)
 	dwc3_enable_susphy(dwc, true);
 }
 
+static enum usb_link_tunnel_mode dwc3_xhci_tunnel_mode(struct usb_hcd *hcd, int portnum)
+{
+	struct platform_device *pdev;
+	struct dwc3 *dwc;
+
+	pdev = to_platform_device(hcd->self.controller);
+	dwc = dev_get_drvdata(pdev->dev.parent);
+
+	return dwc3_link_tunnel_mode(dwc, portnum);
+}
+
 static const struct xhci_plat_priv dwc3_xhci_plat_quirk = {
 	.plat_start = dwc3_xhci_plat_start,
+	.tunnel_mode = dwc3_xhci_tunnel_mode,
 };
 
 static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,

-- 
2.54.0

Re: [PATCH 1/2] usb: host: xhci: Allow non-Intel usb_link_tunnel_mode reporting

[Mika Westerberg]

Hi,

On Tue, May 05, 2026 at 10:55:04AM +0200, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 
> The Thunderbolt framework relies on the USB core to create device links
> for tunneled ports, so that the USB3 controller is only kept
> runtime-resumed for the duration of the tunneling.
> 
> Currently, retrieving that information is only possibe on Intel XHCI
> hosts, through a vendor-specific capability. Extend xhci-plat to allow
> plumbing a custom one.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> ---
>  drivers/usb/host/xhci-hub.c  | 4 ++--
>  drivers/usb/host/xhci-plat.c | 2 ++
>  drivers/usb/host/xhci-plat.h | 1 +
>  drivers/usb/host/xhci.c      | 6 +++++-
>  drivers/usb/host/xhci.h      | 5 ++++-
>  5 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
> index bacd0ddd0d09..09e5da912066 100644
> --- a/drivers/usb/host/xhci-hub.c
> +++ b/drivers/usb/host/xhci-hub.c
> @@ -750,7 +750,7 @@ static int xhci_exit_test_mode(struct xhci_hcd *xhci)
>  }
>  
>  /**
> - * xhci_port_is_tunneled() - Check if USB3 connection is tunneled over USB4
> + * xhci_port_tunnel_mode() - Check if USB3 connection is tunneled over USB4
>   * @xhci: xhci host controller
>   * @port: USB3 port to be checked.
>   *
> @@ -764,7 +764,7 @@ static int xhci_exit_test_mode(struct xhci_hcd *xhci)
>   * detecting USB3 over USB4 tunnels. USB_LINK_NATIVE or USB_LINK_TUNNELED
>   * otherwise.
>   */
> -enum usb_link_tunnel_mode xhci_port_is_tunneled(struct xhci_hcd *xhci,
> +enum usb_link_tunnel_mode xhci_port_tunnel_mode(struct xhci_hcd *xhci,
>  						struct xhci_port *port)

I'm wondering if this could be:

bool xhci_port_is_tunneled()

becase if I understand correctly that's the only information we need e.g is
it going over tunnel or not.