Re: [PATCH resend] arm64: dts: mediatek: mt8192: Mark scp_adsp clock as broken

[AngeloGioacchino Del Regno]

Il 01/12/22 09:56, Chen-Yu Tsai ha scritto:
> On Wed, Nov 30, 2022 at 7:10 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
> > Il 30/11/22 04:17, Chen-Yu Tsai ha scritto:
> > > The scp_adsp clock controller is under the SCP_ADSP power domain. This
> > > power domain is currently not supported nor defined.
> > >
> > > Mark the clock controller as broken for now, to avoid the system from
> > > trying to access it, and causing the CPU or bus to stall.
> > >
> > > Fixes: 5d2b897bc6f5 ("arm64: dts: mediatek: Add mt8192 clock controllers")
> > > Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> >
> > ....or we can add the ADSP power domain to actually fix this properly, which looks
> > like being a generally good idea :-)
>
> Sure, but that and any driver changes have to be backported, or anything
> touching the clocks will still break the system.

I agree.

> There's no reason we can't have both. I think having this one merged and
> backported to stable first, then adding the SCP_ADSP power domain, and tying
> it to the clock controller as a follow up addition works best.
>
> What do you think?

I think that one reason to not have both is that we'd have to revert this commit
after the SCP_ADSP power domain is added (with the appropriate Fixes tags and/or
Cc stable)...

I'd expect that entire addition to be no more than 3 commits, including the dtsi
one... and if it comes out as I expect, we'd be solving that issue on all of the
affected older versions of the kernel - the right way.

Can we wait for... let's say, a day or two to check how that works, before taking
a final decision on this commit?

Cheers,
Angelo

> ChenYu
>
> > Allen, can you please take care of that?
> >
> > Thank you,
> > Angelo
> >
> > > ---
> > >    arch/arm64/boot/dts/mediatek/mt8192.dtsi | 2 ++
> > >    1 file changed, 2 insertions(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/mediatek/mt8192.dtsi b/arch/arm64/boot/dts/mediatek/mt8192.dtsi
> > > index 6b20376191a7..ef91941848ae 100644
> > > --- a/arch/arm64/boot/dts/mediatek/mt8192.dtsi
> > > +++ b/arch/arm64/boot/dts/mediatek/mt8192.dtsi
> > > @@ -575,6 +575,8 @@ scp_adsp: clock-controller@10720000 {
> > >                        compatible = "mediatek,mt8192-scp_adsp";
> > >                        reg = <0 0x10720000 0 0x1000>;
> > >                        #clock-cells = <1>;
> > > +                     /* power domain dependency not upstreamed */
> > > +                     status = "broken";
> > >                };
> > >
> > >                uart0: serial@11002000 {