[PATCH v3 1/1] usb:host:xhci support option to disable the xHCI USB2 HW LPM

[PATCH v3 1/1] usb:host:xhci support option to disable the xHCI USB2 HW LPM

[Thang Q. Nguyen]

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@apm.com>
Signed-off-by: Thang Q. Nguyen <tqnguyen@apm.com>
---
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                            |    3 +++
 drivers/usb/host/xhci.h                            |    1 +
 4 files changed, 8 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 30f47d9..49d05c7 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4061,6 +4061,9 @@ 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;
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 73a28a9..03d50e8 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1819,6 +1819,7 @@ struct xhci_hcd {
 /* For controller with a broken Port Disable implementation */
 #define XHCI_BROKEN_PORT_PED	(1 << 25)
 #define XHCI_LIMIT_ENDPOINT_INTERVAL_7	(1 << 26)
+#define XHCI_HW_LPM_DISABLE	(1 << 27)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
-- 
1.7.1

Re: [PATCH v3 1/1] usb:host:xhci support option to disable the xHCI USB2 HW LPM

[Rob Herring]

On Fri, Jun 23, 2017 at 10:02:12AM +0700, Thang Q. Nguyen wrote:
> 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@apm.com>
> Signed-off-by: Thang Q. Nguyen <tqnguyen@apm.com>
> ---
> 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                            |    3 +++
>  drivers/usb/host/xhci.h                            |    1 +
>  4 files changed, 8 insertions(+), 0 deletions(-)

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v3 1/1] usb:host:xhci support option to disable the xHCI USB2 HW LPM

[Thang Q. Nguyen]

On Fri, Jun 23, 2017 at 10:02 AM, Thang Q. Nguyen <tqnguyen@apm.com> wrote:
> 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@apm.com>
> Signed-off-by: Thang Q. Nguyen <tqnguyen@apm.com>
> ---
> 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                            |    3 +++
>  drivers/usb/host/xhci.h                            |    1 +
>  4 files changed, 8 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 30f47d9..49d05c7 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -4061,6 +4061,9 @@ 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;
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index 73a28a9..03d50e8 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1819,6 +1819,7 @@ struct xhci_hcd {
>  /* For controller with a broken Port Disable implementation */
>  #define XHCI_BROKEN_PORT_PED   (1 << 25)
>  #define XHCI_LIMIT_ENDPOINT_INTERVAL_7 (1 << 26)
> +#define XHCI_HW_LPM_DISABLE    (1 << 27)
>
>         unsigned int            num_active_eps;
>         unsigned int            limit_active_eps;
> --
> 1.7.1
>
Hi,
Is there any other comment on the patch?

Regards,
Thang Q. Nguyen

Re: [PATCH v3 1/1] usb:host:xhci support option to disable the xHCI USB2 HW LPM

[Greg Kroah-Hartman]

On Sun, Jul 09, 2017 at 12:38:19PM +0700, Thang Q. Nguyen wrote:
> On Fri, Jun 23, 2017 at 10:02 AM, Thang Q. Nguyen <tqnguyen@apm.com> wrote:
> > 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@apm.com>
> > Signed-off-by: Thang Q. Nguyen <tqnguyen@apm.com>
> > ---
> > 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                            |    3 +++
> >  drivers/usb/host/xhci.h                            |    1 +
> >  4 files changed, 8 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 30f47d9..49d05c7 100644
> > --- a/drivers/usb/host/xhci.c
> > +++ b/drivers/usb/host/xhci.c
> > @@ -4061,6 +4061,9 @@ 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;
> > diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> > index 73a28a9..03d50e8 100644
> > --- a/drivers/usb/host/xhci.h
> > +++ b/drivers/usb/host/xhci.h
> > @@ -1819,6 +1819,7 @@ struct xhci_hcd {
> >  /* For controller with a broken Port Disable implementation */
> >  #define XHCI_BROKEN_PORT_PED   (1 << 25)
> >  #define XHCI_LIMIT_ENDPOINT_INTERVAL_7 (1 << 26)
> > +#define XHCI_HW_LPM_DISABLE    (1 << 27)
> >
> >         unsigned int            num_active_eps;
> >         unsigned int            limit_active_eps;
> > --
> > 1.7.1
> >
> Hi,
> Is there any other comment on the patch?

Relax, it's the middle of the merge window, we can't do anything with
patches until after 4.13-rc1 comes out a the earliest...

greg k-h