RE: [PATCH v2 1/2] dt-bindings: usb: dwc3-xilinx: Add documentation for Versal DWC3 Controller

Manish Narani
2020-09-25T06:07:09Z

Hi Rob/Felipe,

Thanks for the review.

> -----Original Message-----
> From: Felipe Balbi <balbi@kernel.org>
> Sent: Thursday, September 24, 2020 12:47 PM
> To: Rob Herring <robh@kernel.org>; Manish Narani <MNARANI@xilinx.com>
> Cc: gregkh@linuxfoundation.org; Michal Simek <michals@xilinx.com>;
> p.zabel@pengutronix.de; linux-usb@vger.kernel.org;
> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> kernel@vger.kernel.org; git <git@xilinx.com>
> Subject: Re: [PATCH v2 1/2] dt-bindings: usb: dwc3-xilinx: Add
> documentation for Versal DWC3 Controller
>
> Rob Herring <robh@kernel.org> writes:
>
> > On Thu, Sep 10, 2020 at 12:33:04AM +0530, Manish Narani wrote:
> >> Add documentation for Versal DWC3 controller. Add required property
> >> 'reg' for the same. Also add optional properties for snps,dwc3.
> >>
> >> Signed-off-by: Manish Narani <manish.narani@xilinx.com>
> >> ---
> >> .../devicetree/bindings/usb/dwc3-xilinx.txt | 20 +++++++++++++++++--
> >> 1 file changed, 18 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/dwc3-xilinx.txt
> b/Documentation/devicetree/bindings/usb/dwc3-xilinx.txt
> >> index 4aae5b2cef56..219b5780dbee 100644
> >> --- a/Documentation/devicetree/bindings/usb/dwc3-xilinx.txt
> >> +++ b/Documentation/devicetree/bindings/usb/dwc3-xilinx.txt
> >> @@ -1,7 +1,8 @@
> >> Xilinx SuperSpeed DWC3 USB SoC controller
> >>
> >> Required properties:
> >> -- compatible: Should contain "xlnx,zynqmp-dwc3"
> >> +- compatible: May contain "xlnx,zynqmp-dwc3" or "xlnx,versal-
> dwc3"
> >> +- reg: Base address and length of the register control block
> >> - clocks: A list of phandles for the clocks listed in clock-names
> >> - clock-names: Should contain the following:
> >> "bus_clk" Master/Core clock, have to be >= 125 MHz for SS
> >> @@ -13,12 +14,24 @@ Required child node:
> >> A child node must exist to represent the core DWC3 IP block. The name of
> >> the node is not important. The content of the node is defined in dwc3.txt.
> >>
> >> +Optional properties for snps,dwc3:
> >> +- dma-coherent: Enable this flag if CCI is enabled in design. Adding this
> >> + flag configures Global SoC bus Configuration Register and
> >> + Xilinx USB 3.0 IP - USB coherency register to enable CCI.
> >> +- snps,enable-hibernation: Add this flag to enable hibernation support
> for
> >> + peripheral mode.
> >
> > This belongs in the DWC3 binding. It also implies that hibernation is
> > not supported by any other DWC3 based platform. Can't this be implied by
> > the compatible string (in the parent)?

Rob, We can move this to dwc3 bindings. If Felipe is okay with below response.

>
> hibernation support is detectable in runtime, and we've been using that.

Felipe, Yes, this flag is to control the enable/disable hibernation.
I did not see has_hibernation flag being set anywhere in the driver.
Can we control the hibernation enable/disable through DT entry? See below:
-----
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 2eb34c8b4065..1baf44d8d566 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -769,8 +769,15 @@ static void dwc3_core_setup_global_control(struct dwc3 *dwc)
reg &= ~DWC3_GCTL_DSBLCLKGTNG;
break;
case DWC3_GHWPARAMS1_EN_PWROPT_HIB:
- /* enable hibernation here */
- dwc->nr_scratch = DWC3_GHWPARAMS4_HIBER_SCRATCHBUFS(hwparams4);
+ if (!device_property_read_bool(dwc->dev,
+ "snps,enable-hibernation")) {
+ dev_dbg(dwc->dev, "Hibernation not enabled\n");
+ } else {
+ /* enable hibernation here */
+ dwc->nr_scratch =
+ DWC3_GHWPARAMS4_HIBER_SCRATCHBUFS(hwparams4);
+ dwc->has_hibernation = 1;
+ }

/*
* REVISIT Enabling this bit so that host-mode hibernation
-----

Please provide your inputs.

Thanks,
Manish