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

Felipe Balbi
2020-09-25T07:12:10Z

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Hi,

Manish Narani <MNARANI@xilinx.com> writes:
> 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;
> + }

I left it off because I didn't have HW to validate. Don't add a new
binding for this. Set has_hibernation to true and make sure it
works. Then send me a patch that sets has_hibernation to true whenever
DWC3_GHWPARAMS1_EN_PWROPT_HIB is valid.

--
balbi

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