[PATCH 1/2] xhci: Introduce "disable-usb3" DT property/quirk

Sam Edwards
2023-12-08T21:05:22Z

Some systems may have xHCI controllers that enumerate USB 3.0 ports, but
these ports nevertheless cannot be used. Perhaps enabling them triggers a
hardware bug, or perhaps they simply aren't connected and it would be
confusing to the user to see an unusable USB 3.0 rhub show up -- whatever
the case may be, it's reasonable to want to disable these ports.

Add a DT property (and associated quirk) to the xHCI driver that skips
over (i.e. ignores and doesn't initialize) any USB 3.0 ports discovered
during driver initialization.

Signed-off-by: Sam Edwards <CFSworks@gmail.com>
---
Documentation/devicetree/bindings/usb/usb-xhci.yaml | 4 ++++
drivers/usb/host/xhci-mem.c | 4 ++++
drivers/usb/host/xhci-plat.c | 3 +++
drivers/usb/host/xhci.h | 1 +
4 files changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.yaml b/Documentation/devicetree/bindings/usb/usb-xhci.yaml
index 180a261c3e8f..8a64e747260a 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.yaml
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.yaml
@@ -25,6 +25,10 @@ properties:
description: Set if the controller has broken port disable mechanism
type: boolean

+ disable-usb3:
+ description: Ignore (don't initialize, don't use) USB3 ports
+ type: boolean
+
imod-interval-ns:
description: Interrupt moderation interval
default: 5000
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 0a37f0d511cf..bf8fcab626e4 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1968,6 +1968,10 @@ static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
minor_revision = XHCI_EXT_PORT_MINOR(temp);

if (major_revision == 0x03) {
+ /* Ignore USB3 ports entirely if USB3 support is disabled. */
+ if (xhci->quirks & XHCI_DISABLE_USB3)
+ return;
+
rhub = &xhci->usb3_rhub;
/*
* Some hosts incorrectly use sub-minor version for minor
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index b93161374293..75285fb5bbbc 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -249,6 +249,9 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev, const s
if (device_property_read_bool(tmpdev, "quirk-broken-port-ped"))
xhci->quirks |= XHCI_BROKEN_PORT_PED;

+ if (device_property_read_bool(tmpdev, "disable-usb3"))
+ xhci->quirks |= XHCI_DISABLE_USB3;
+
device_property_read_u32(tmpdev, "imod-interval-ns",
&xhci->imod_interval);
}
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 5df370482521..c53fbeea478f 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1906,6 +1906,7 @@ struct xhci_hcd {
#define XHCI_RESET_TO_DEFAULT BIT_ULL(44)
#define XHCI_ZHAOXIN_TRB_FETCH BIT_ULL(45)
#define XHCI_ZHAOXIN_HOST BIT_ULL(46)
+#define XHCI_DISABLE_USB3 BIT_ULL(47)

unsigned int num_active_eps;
unsigned int limit_active_eps;
--
2.41.0