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

From: Felipe Balbi
Date: Thu Dec 08 2016 - 04:41:28 EST


Hi,

Baolin Wang <baolin.wang@xxxxxxxxxx> writes:
> Hi Felipe,
>
> On 28 November 2016 at 14:43, Baolin Wang <baolin.wang@xxxxxxxxxx> 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@xxxxxxxxxx>
>> ---
>> 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

why do you need another Kconfig for this? Just enable it already :-p

>> 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);

why do you need this?

>> @@ -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 pm_runtime_put_sync() is probably enough here.

>> +
>> + 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);

likewise.

>> + 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
> --
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--
balbi

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