Re: [PATCH 4/4] usb: dwc3: core: Support the dwc3 host suspend/resume

From: Baolin Wang
Date: Thu Aug 18 2016 - 04:59:59 EST

Hi Felipe,

On 18 August 2016 at 15:33, Felipe Balbi <balbi@xxxxxxxxxx> wrote:
>
> Hi,
>
> Baolin Wang <baolin.wang@xxxxxxxxxx> 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, and
>> we also should enable the 'XHCI_SLOW_SUSPEND' quirk for extraordinary delay when
>> suspending the xhci.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
>> ---
>> drivers/usb/dwc3/Kconfig | 7 +++++++
>> drivers/usb/dwc3/core.c | 25 ++++++++++++++++++++++++-
>> drivers/usb/dwc3/core.h | 15 +++++++++++++++
>> drivers/usb/dwc3/host.c | 32 ++++++++++++++++++++++++++++++++
>> 4 files changed, 78 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
>> index a64ce1c..725d2bd 100644
>> --- a/drivers/usb/dwc3/Kconfig
>> +++ b/drivers/usb/dwc3/Kconfig
>> @@ -45,6 +45,13 @@ config USB_DWC3_DUAL_ROLE
>> This is the default mode of working of DWC3 controller where
>> both host and gadget features are enabled.
>>
>> +config USB_DWC3_HOST_SUSPEND
>> + bool "Choose if the 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.
>> +
>> endchoice
>>
>> comment "Platform Glue Driver Support"
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 1485480..5140b4d 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -1103,15 +1103,27 @@ 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;
>> @@ -1133,12 +1145,23 @@ 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 45d6de5..0ba203e 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -1177,4 +1177,19 @@ static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
>> { }
>> #endif
>>
>> +#if IS_ENABLED(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 2e960ed..2ec3eff 100644
>> --- a/drivers/usb/dwc3/host.c
>> +++ b/drivers/usb/dwc3/host.c
>> @@ -17,8 +17,11 @@
>>
>> #include <linux/platform_device.h>
>> #include <linux/usb/xhci_pdriver.h>
>> +#include <linux/usb.h>
>> +#include <linux/usb/hcd.h>
>>
>> #include "core.h"
>> +#include "../host/xhci.h"
>>
>> int dwc3_host_init(struct dwc3 *dwc)
>> {
>> @@ -91,6 +94,8 @@ int dwc3_host_init(struct dwc3 *dwc)
>> memset(&pdata, 0, sizeof(pdata));
>>
>> pdata.usb3_lpm_capable = dwc->usb3_lpm_capable;
>> + /* dwc3 controller need an extraordinary delay when suspending xhci. */
>> + pdata.usb3_slow_suspend = 1;
>>
>> ret = platform_device_add_data(xhci, &pdata, sizeof(pdata));
>> if (ret) {
>> @@ -128,3 +133,30 @@ 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 usb_hcd *hcd = dev_get_drvdata(&dwc->xhci->dev);
>> + struct xhci_hcd *xhci = hcd_to_xhci(hcd);
>> + int ret, cnt = 20;
>> +
>> +try_again:
>> + /* We should wait for xhci bus has been into suspend mode firstly. */
>> + ret = xhci_suspend(xhci, device_may_wakeup(&dwc->xhci->dev));
>> + if (ret && --cnt > 0) {
>> + dev_warn(dwc->dev, "xhci suspend failed %d, try again...\n",
>> + ret);
>> + msleep(200);
>> + goto try_again;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +int dwc3_host_resume(struct dwc3 *dwc)
>> +{
>> + struct usb_hcd *hcd = dev_get_drvdata(&dwc->xhci->dev);
>> + struct xhci_hcd *xhci = hcd_to_xhci(hcd);
>> +
>> + return xhci_resume(xhci, 0);
>> +}
>
> This is wrong. XHCI is a child of dwc3, when dwc3 suspends,
> xhci_supend() has already been called. Why isn't it called for you?

xhci-plat.c did not set the runtime PM callbacks, how can we issued
xhci_supend() by runtime PM from dwc3?

--
Baolin.wang
Best Regards