XHCI specification 1.1 does not require xHCI-compliant controllers
to always enable hardware USB2 LPM. However, the current xHCI
driver always enable it when seeing HLC=1.
This patch supports an option for users to control disabling
USB2 Hardware LPM via DT/ACPI attribute.
This option is needed in case user would like to disable this
feature. For example, their xHCI controller has its USB2 HW LPM
broken.
Signed-off-by: Tung Nguyen <tunguyen@xxxxxxx>
Signed-off-by: Thang Q. Nguyen <tqnguyen@xxxxxxx>
---
Changes since v3:
- Bypass updating LPM parameters when HW LPM is optionally disabled.
Changes since v2:
- Change code to disable HW LPM as an option for user which
is set via ACPI/DT.
Changes since v1:
- Update DT/ACPI attribute and corresponding codes from HLE to LPM to
be consistent with other attribute names.
---
Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 +
drivers/usb/host/xhci-plat.c | 3 +++
drivers/usb/host/xhci.c | 6 ++++++
drivers/usb/host/xhci.h | 1 +
4 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index 2d80b60..ae6e484 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -26,6 +26,7 @@ Required properties:
Optional properties:
- clocks: reference to a clock
+ - usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
- usb3-lpm-capable: determines if platform is USB3 LPM capable
- quirk-broken-port-ped: set if the controller has broken port disable mechanism
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index c04144b..9028fb5 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -267,6 +267,9 @@ static int xhci_plat_probe(struct platform_device *pdev)
goto disable_clk;
}
+ if (device_property_read_bool(sysdev, "usb2-lpm-disable"))
+ xhci->quirks |= XHCI_HW_LPM_DISABLE;
+
if (device_property_read_bool(sysdev, "usb3-lpm-capable"))
xhci->quirks |= XHCI_LPM_SUPPORT;
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 56f85df..73b24bc 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4060,6 +4060,9 @@ static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
!udev->lpm_capable)
return -EPERM;
+ if (xhci->quirks & XHCI_HW_LPM_DISABLE)
+ return -EPERM;
+
if (!udev->parent || udev->parent->parent ||
udev->descriptor.bDeviceClass == USB_CLASS_HUB)
return -EPERM;
@@ -4177,6 +4180,9 @@ static int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
!udev->lpm_capable)
return 0;
+ if (xhci->quirks & XHCI_HW_LPM_DISABLE)
+ return 0;
+
/* we only support lpm for non-hub device connected to root hub yet */
if (!udev->parent || udev->parent->parent ||
udev->descriptor.bDeviceClass == USB_CLASS_HUB)
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 3c6da1f..3cbf4a9 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1820,6 +1820,7 @@ struct xhci_hcd {
#define XHCI_BROKEN_PORT_PED (1 << 25)
#define XHCI_LIMIT_ENDPOINT_INTERVAL_7 (1 << 26)
#define XHCI_U2_DISABLE_WAKE (1 << 27)
+#define XHCI_HW_LPM_DISABLE (1 << 28)
unsigned int num_active_eps;
unsigned int limit_active_eps;
--
1.7.1
--
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