[PATCH v4 05/12] power-domain: Add refcounting

[Simon Glass]

Hi Miquel,

On Mon, 3 Mar 2025 at 01:43, Miquel Raynal <miquel.raynal at bootlin.com> wrote:
>
> Hello Simon,
>
> On 08/02/2025 at 08:09:30 -03, Fabio Estevam <festevam at gmail.com> wrote:
>
> > Hi Simon,
> >
> > On Wed, Jan 29, 2025 at 7:22 AM Miquel Raynal <miquel.raynal at bootlin.com> wrote:
> >>
> >> It is very surprising that such an uclass, specifically designed to
> >> handle resources that may be shared by different devices, is not keeping
> >> the count of the number of times a power domain has been
> >> enabled/disabled to avoid shutting it down unexpectedly or disabling it
> >> several times.
> >>
> >> Doing this causes troubles on eg. i.MX8MP because disabling power
> >> domains can be done in recursive loops were the same power domain
> >> disabled up to 4 times in a row. PGCs seem to have tight FSM internal
> >> timings to respect and it is easy to produce a race condition that puts
> >> the power domains in an unstable state, leading to ADB400 errors and
> >> later crashes in Linux.
> >>
> >> CI tests using power domains are slightly updated to make sure the count
> >> of on/off calls is even and the results match what we *now* expect.
> >>
> >> As we do not want to break existing users while stile getting
> >> interesting error codes, the implementation is split between:
> >> - a low-level helper reporting error codes if the requested transition
> >>   could not be operated,
> >> - a higher-level helper ignoring the "non error" codes, like EALREADY and
> >>   EBUSY.
> >>
> >> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> >
> > Are you happy with this version?
>
> Would you have any feedback on this? I believe we agreed on the
> implementation but it's been a month and I didn't heard back from you
> since then, and I believe Fabio was waiting for your feedback.
>
> Thanks a lot,
> Miquèl

Yes it looks fine to me, thanks.

Reviewed-by: Simon Glass <sjg at chromium.org>

Regards,
Simon