Re: [PATCH] arm64: dts: qcom: sc7280: Set modem FW path for Chrome OS boards

[Matthias Kaehlcke <mka@chromium.org>]

On Tue, May 10, 2022 at 12:49:30PM -0700, Doug Anderson wrote:
> Hi,
> 
> On Tue, May 10, 2022 at 10:47 AM Matthias Kaehlcke <mka@chromium.org> wrote:
> >
> > Specify the path of the modem FW for SC7280 Chrome OS boards in
> > the 'remoteproc_mpss' node.
> >
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> >
> >  arch/arm64/boot/dts/qcom/sc7280-chrome-common.dtsi | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/sc7280-chrome-common.dtsi b/arch/arm64/boot/dts/qcom/sc7280-chrome-common.dtsi
> > index 9f4a9c263c35..995c5bd12549 100644
> > --- a/arch/arm64/boot/dts/qcom/sc7280-chrome-common.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sc7280-chrome-common.dtsi
> > @@ -89,6 +89,8 @@ &remoteproc_mpss {
> >         compatible = "qcom,sc7280-mss-pil";
> >         iommus = <&apps_smmu 0x124 0x0>, <&apps_smmu 0x488 0x7>;
> >         memory-region = <&mba_mem>, <&mpss_mem>;
> > +       firmware-name = "qcom/sc7280-herobrine/modem/mba.mbn",
> > +                       "qcom/sc7280-herobrine/modem/qdsp6sw.mbn";
> 
> We don't necessarily need to change anything, but a few thoughts:
> 
> 1. I guess technically we don't actually need the "modem" subdirectory
> for herobrine, right? WiFi works differently on sc7280 so we won't
> have a "no modem" modem firmware. ...but I guess it doesn't hurt to
> have it and it's nice to keep it symmetric.

Yeah, it seems nice to keep it symmetric and also indicate for what
kind of device the firmware is for. 'sc7280-herobrine' (or
'sc7280-chrome') doesn't reveal that.

> 2. Whenever we're ready to support WiFi only SKUs then I guess it'll
> still be OK to specify the firmware name. We'll just set the status of
> "&mdss_dp" to "disabled".

Yes, specifying the FW name is not a problem. Either we'll set the
status of 'remoteproc_mpss' to 'disabled' or have a DT snippet for
the modem that is only included for SKUs with a modem.

> 3. It's slightly weird that we're using the name "herobrine" but
> putting the change in the "chrome-common.dtsi" file. Should it be
> "sc7280-chrome" instead?

Currently OS images have the FW in 'qcom/sc7280-herobrine', but we
could change that if desired. If we change the path we could also
consider to change it to 'qcom/sc7280-q6v5' or 'qcom/sc7280-mpss'
instead of 'qcom/sc7280-chrome/modem'.