Re: [PATCH v4 2/2] usb: dwc3: core: Support the dwc3 host suspend/resume

[Baolin Wang <baolin.wang@linaro.org>]

Hi Felipe,

On 28 November 2016 at 14:43, Baolin Wang <baolin.wang@linaro.org> wrote:
> For some mobile devices with strict power management, we also want to suspend
> the host when the slave is detached for power saving. Thus we add the host
> suspend/resume functions to support this requirement.
>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
> Changes since v3:
>  - No updates.
>
> Changes since v2:
>  - Remove pm_children_suspended() and other unused macros.
>
>  Changes since v1:
>    - Add pm_runtime.h head file to avoid kbuild error.
> ---
>  drivers/usb/dwc3/Kconfig |    7 +++++++
>  drivers/usb/dwc3/core.c  |   26 +++++++++++++++++++++++++-
>  drivers/usb/dwc3/core.h  |   15 +++++++++++++++
>  drivers/usb/dwc3/host.c  |   37 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 84 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
> index a45b4f1..47bb2f3 100644
> --- a/drivers/usb/dwc3/Kconfig
> +++ b/drivers/usb/dwc3/Kconfig
> @@ -47,6 +47,13 @@ config USB_DWC3_DUAL_ROLE
>
>  endchoice
>
> +config USB_DWC3_HOST_SUSPEND
> +       bool "Choose if the DWC3 host (xhci) can be suspend/resume"
> +       depends on USB_DWC3_HOST=y || USB_DWC3_DUAL_ROLE=y
> +       help
> +         We can suspend the host when the slave is detached for power saving,
> +         and resume the host when one slave is attached.
> +
>  comment "Platform Glue Driver Support"
>
>  config USB_DWC3_OMAP
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 9a4a5e4..7ad4bc3 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1091,6 +1091,7 @@ static int dwc3_probe(struct platform_device *pdev)
>         pm_runtime_use_autosuspend(dev);
>         pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);
>         pm_runtime_enable(dev);
> +       pm_suspend_ignore_children(dev, true);
>         ret = pm_runtime_get_sync(dev);
>         if (ret < 0)
>                 goto err1;
> @@ -1215,15 +1216,27 @@ static int dwc3_remove(struct platform_device *pdev)
>  static int dwc3_suspend_common(struct dwc3 *dwc)
>  {
>         unsigned long   flags;
> +       int             ret;
>
>         switch (dwc->dr_mode) {
>         case USB_DR_MODE_PERIPHERAL:
> +               spin_lock_irqsave(&dwc->lock, flags);
> +               dwc3_gadget_suspend(dwc);
> +               spin_unlock_irqrestore(&dwc->lock, flags);
> +               break;
>         case USB_DR_MODE_OTG:
> +               ret = dwc3_host_suspend(dwc);
> +               if (ret)
> +                       return ret;
> +
>                 spin_lock_irqsave(&dwc->lock, flags);
>                 dwc3_gadget_suspend(dwc);
>                 spin_unlock_irqrestore(&dwc->lock, flags);
>                 break;
>         case USB_DR_MODE_HOST:
> +               ret = dwc3_host_suspend(dwc);
> +               if (ret)
> +                       return ret;
>         default:
>                 /* do nothing */
>                 break;
> @@ -1245,12 +1258,23 @@ static int dwc3_resume_common(struct dwc3 *dwc)
>
>         switch (dwc->dr_mode) {
>         case USB_DR_MODE_PERIPHERAL:
> +               spin_lock_irqsave(&dwc->lock, flags);
> +               dwc3_gadget_resume(dwc);
> +               spin_unlock_irqrestore(&dwc->lock, flags);
> +               break;
>         case USB_DR_MODE_OTG:
> +               ret = dwc3_host_resume(dwc);
> +               if (ret)
> +                       return ret;
> +
>                 spin_lock_irqsave(&dwc->lock, flags);
>                 dwc3_gadget_resume(dwc);
>                 spin_unlock_irqrestore(&dwc->lock, flags);
> -               /* FALLTHROUGH */
> +               break;
>         case USB_DR_MODE_HOST:
> +               ret = dwc3_host_resume(dwc);
> +               if (ret)
> +                       return ret;
>         default:
>                 /* do nothing */
>                 break;
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index b585a30..db41908 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1226,4 +1226,19 @@ static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
>  { }
>  #endif
>
> +#if IS_ENABLED(CONFIG_USB_DWC3_HOST_SUSPEND)
> +int dwc3_host_suspend(struct dwc3 *dwc);
> +int dwc3_host_resume(struct dwc3 *dwc);
> +#else
> +static inline int dwc3_host_suspend(struct dwc3 *dwc)
> +{
> +       return 0;
> +}
> +
> +static inline int dwc3_host_resume(struct dwc3 *dwc)
> +{
> +       return 0;
> +}
> +#endif
> +
>  #endif /* __DRIVERS_USB_DWC3_CORE_H */
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index ed82464..8e5309d6 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -16,6 +16,7 @@
>   */
>
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>
>  #include "core.h"
>
> @@ -130,3 +131,39 @@ void dwc3_host_exit(struct dwc3 *dwc)
>                           dev_name(&dwc->xhci->dev));
>         platform_device_unregister(dwc->xhci);
>  }
> +
> +#ifdef CONFIG_USB_DWC3_HOST_SUSPEND
> +int dwc3_host_suspend(struct dwc3 *dwc)
> +{
> +       struct device *xhci = &dwc->xhci->dev;
> +       int ret;
> +
> +       /*
> +        * Note: if we get the -EBUSY, which means the xHCI children devices are
> +        * not in suspend state yet, the glue layer need to wait for a while and
> +        * try to suspend xHCI device again.
> +        */
> +       ret = pm_runtime_put_sync(xhci);
> +       if (ret) {
> +               dev_err(xhci, "failed to suspend xHCI device\n");
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +int dwc3_host_resume(struct dwc3 *dwc)
> +{
> +       struct device *xhci = &dwc->xhci->dev;
> +       int ret;
> +
> +       /* Resume the xHCI device synchronously. */
> +       ret = pm_runtime_get_sync(xhci);
> +       if (ret) {
> +               dev_err(xhci, "failed to resume xHCI device\n");
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +#endif
> --
> 1.7.9.5
>

How do you think this patch and do you have any suggestion? Thanks.

-- 
Baolin.wang
Best Regards