On Tue, Jul 11, 2023, Elson Roy Serrao wrote: > Changes in v3 > - Added a dt property 'snps,allow-rtsusp-on-u3' to make this feature platform > dependent as per the feedback from Thinh N. > - Changed the RT idle/suspend/resume handling to device mode specific and dt > property dependent. > - Modified the cover letter to document how resume is handled on qcom platforms. > > Changes in v2 > - Used pm_runtime_resume_and_get() API instead of pm_runtime_get_sync() > as suggested by Dan. > - Handled the return value in ether_wakeup_host to print error message. > > When a USB link is idle, the host sends a bus suspend event to the device > so that the device can save power. But true power savings during bus > suspend can be seen only if we let the USB controller enter low power > mode and turn off the clocks. Vendor drivers may have their own runtime > power management framework to power up/down the controller. But since > vendor drivers' runtime suspend/resume routines depend on the dwc3 child > node we would need a framework to trigger dwc3 runtime pm ops whenever a > bus suspend is received. If the device wants to exit from bus suspend > state it can send a wakeup signal to the host by first bringing out the > controller from low power mode. This series implements the needed > framework to achieve this functionality when a bus suspend interupt is > received. The assumption here is that the dwc3 hibernation feature is not > enabled and the platform is responsible in detecting the resume events to > bring the controller out of suspend. > > On Qualcomm platforms the bus resume is handled through Phy and informed to > software through wakeup capable phy interrupts. > usb2 PHY is configured to detect the Resume K event and sends an interrupt > when this event is detected. This would trigger the runtime resume of the > glue driver which would intrinsically wakeup the dwc3 child. In case of usb3 PHY, > it is configured to detect the LFPS wake signal during bus resume and the > corresponding interrupt triggers the runtime resume of the glue driver. Thanks for the info confirming that it's capable for both usb3 and usb2. BR, Thinh > > The series is organized in below fashion: > Patch 1: This includes the modification needed from function drivers to let > UDC enter low power mode with u_ether as an example. > Patch 2: New dt property to allow dwc3 runtime suspedn during bus suspend scenario. > Patch 3: This has the modification needed in the UDC driver to trigger runtime > suspend whene a bus suspend interrupt is received. Since this is a platform > dependent change it is made applicable through a dt property. This also handles > resume and remote wakeup modifications from power management perspective. > > Elson Roy Serrao (3): > usb: function: u_ether: Handle rx requests during suspend/resume > dt-bindings: usb: snps,dwc3: Add allow-rtsusp-on-u3 property > usb: dwc3: Modify runtime pm ops to handle bus suspend > > .../devicetree/bindings/usb/snps,dwc3.yaml | 5 ++ > drivers/usb/dwc3/core.c | 26 ++++++++-- > drivers/usb/dwc3/core.h | 3 ++ > drivers/usb/dwc3/gadget.c | 40 +++++++++++++--- > drivers/usb/gadget/function/u_ether.c | 47 +++++++++++++++---- > 5 files changed, 102 insertions(+), 19 deletions(-) > > -- > 2.17.1 >
