Hi,
On 7/21/2017 12:28 PM, Baolin Wang wrote:
For some mobile devices with strict power management, we also want to suspend the host when the slave was detached for power saving. Thus adding the host suspend/resume functions to support this requirement.
USB/PM core already takes care of suspending root-HUB/XHCI when no device connected.
We will issue the pm_suspend_ignore_children() for the dwc3 device, since we will resume the child device (xHCI device) in runtime resume callback (dwc3_host_resume()) of dwc3 device, now the dwc3 device's runtime state is not RPM_ACTIVE, which will block to resume its child device (xHCI device). Add ignore children flag can avoid this situation.
This defeats the basic purpose of runtime PM. Without ignore_children once USB bus is suspended, dwc3 gets suspended and then dwc3 glue device. Only requirement I see from the patch is to resume XHCI/root-hub on dwc3 resume. I am sure there must be other way to deal with that e.g. doing same from glue driver by using a wq or use pm_request_resume()
Signed-off-by: Baolin Wang baolin.wang@linaro.org
drivers/usb/dwc3/core.c | 26 +++++++++++++++++++++++++- drivers/usb/dwc3/core.h | 7 +++++++ drivers/usb/dwc3/host.c | 15 +++++++++++++++ 3 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 326b302..2be7ddc 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1193,6 +1193,7 @@ 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;
@@ -1292,15 +1293,27 @@ static int dwc3_remove(struct platform_device *pdev) static int dwc3_suspend_common(struct dwc3 *dwc)
What is the trigger for runtime suspend now that you have ignore_children set.
{ 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;ret = dwc3_host_suspend(dwc);
With DRD/OTG, if current mode is device and dwc3->xhci won't be valid. You can refer to the patch that I pushed to address this.
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;@@ -1322,12 +1335,23 @@ 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;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;ret = dwc3_host_resume(dwc);if (ret)return ret;diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index ea910ac..9b5a4eb 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -1193,11 +1193,18 @@ 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 76f0b0d..3fa4414 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" @@ -151,3 +152,17 @@ void dwc3_host_exit(struct dwc3 *dwc) dev_name(dwc->dev)); platform_device_unregister(dwc->xhci); }
+int dwc3_host_suspend(struct dwc3 *dwc) +{
- struct device *xhci = &dwc->xhci->dev;
- return pm_runtime_suspend(xhci);
If ignore_children is not marked then xhci would indeed be suspended.
+}
+int dwc3_host_resume(struct dwc3 *dwc) +{
- struct device *xhci = &dwc->xhci->dev;
- return pm_runtime_resume(xhci);
Other than what I pushed in my patch - ("usb: dwc3: Don't reinitialize core during host bus-suspend/resume") Just performing pm_request_resume or handling same in dwc3 glue driver should be sufficient. Also, what is trigger for runtime_resume for your platform?