Re: [PATCH v5 2/2] usb: dwc3: core: Support the dwc3 host suspend/resume

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

Hi,

On 16 January 2017 at 18:28, Felipe Balbi <balbi@kernel.org> wrote:
>
> Hi,
>
> Baolin Wang <baolin.wang@linaro.org> writes:
>> 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 v4:
>>  - Remove Kconfig and just enable host suspend/resume.
>>  - Simplify the dwc3_host_suspend/resume() function.
>>
>> 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/core.c |   26 +++++++++++++++++++++++++-
>>  drivers/usb/dwc3/core.h |    7 +++++++
>>  drivers/usb/dwc3/host.c |   21 +++++++++++++++++++++
>>  3 files changed, 53 insertions(+), 1 deletion(-)
>>
>> 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..1099168 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -1158,11 +1158,18 @@ static inline bool dwc3_is_usb31(struct dwc3 *dwc)
>>  #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);
>> +int dwc3_host_suspend(struct dwc3 *dwc);
>> +int dwc3_host_resume(struct dwc3 *dwc);
>>  #else
>>  static inline int dwc3_host_init(struct dwc3 *dwc)
>>  { return 0; }
>>  static inline void dwc3_host_exit(struct dwc3 *dwc)
>>  { }
>> +
>> +static inline int dwc3_host_suspend(struct dwc3 *dwc)
>> +{ return 0; }
>> +static inline int dwc3_host_resume(struct dwc3 *dwc)
>> +{ return 0; }
>>  #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 ed82464..7959ef0 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 +131,23 @@ void dwc3_host_exit(struct dwc3 *dwc)
>>                         dev_name(&dwc->xhci->dev));
>>       platform_device_unregister(dwc->xhci);
>>  }
>> +
>> +int dwc3_host_suspend(struct dwc3 *dwc)
>> +{
>> +     struct device *xhci = &dwc->xhci->dev;
>> +
>> +     /*
>> +      * 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.
>> +      */
>> +     return pm_runtime_put_sync(xhci);
>> +}
>> +
>> +int dwc3_host_resume(struct dwc3 *dwc)
>> +{
>> +     struct device *xhci = &dwc->xhci->dev;
>> +
>> +     /* Resume the xHCI device synchronously. */
>> +     return pm_runtime_get_sync(xhci);
>> +}
>> --
>> 1.7.9.5
>
> I can't take this without Mathias taking xhci side of things.

Okay, I will wait for Mathias' comments. Thanks.

-- 
Baolin.wang
Best Regards