From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754564AbdGUJBG (ORCPT ); Fri, 21 Jul 2017 05:01:06 -0400 Received: from mail-oi0-f45.google.com ([209.85.218.45]:35645 "EHLO mail-oi0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754537AbdGUJBE (ORCPT ); Fri, 21 Jul 2017 05:01:04 -0400 MIME-Version: 1.0 In-Reply-To: <0f1345b4-292c-1881-8bba-d81293b9ace8@codeaurora.org> References: <2086ce508be1c1d75d47c892a5be9593b12fa6f3.1500619870.git.baolin.wang@linaro.org> <0f1345b4-292c-1881-8bba-d81293b9ace8@codeaurora.org> From: Baolin Wang Date: Fri, 21 Jul 2017 17:01:02 +0800 Message-ID: Subject: Re: [PATCH] usb: dwc3: Support the dwc3 host suspend/resume To: Manu Gautam Cc: Felipe Balbi , Greg KH , USB , LKML , Linaro Kernel Mailman List , Mark Brown Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21 July 2017 at 16:45, Manu Gautam wrote: > 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. Correct, but what I mean is we can power off the dwc3 controller when there are 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() Ah, I will try pm_request_resume(). > >> >> Signed-off-by: Baolin Wang >> --- >> 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; >> case USB_DR_MODE_OTG: >> + ret = dwc3_host_suspend(dwc); > With DRD/OTG, if current mode is device and dwc3->xhci won't be valid. If current mode is device, then xHCI device is always in suspend state. > 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; >> default: >> /* do nothing */ >> break; >> @@ -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; >> 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 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 >> +#include >> >> #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. Yes. > Also, what is trigger for runtime_resume for your platform? In our platform glue layer, we have extcon events to notify there are devices connected, then gule layer will resume dwc3 device. -- Baolin.wang Best Regards