On Thu, Aug 7, 2025 at 2:43 AM Geert Uytterhoeven [off-list ref] wrote:

Hi Ulf,

On Wed, 30 Jul 2025 at 12:29, Ulf Hansson [off-list ref] wrote:

quoted

On Wed, 30 Jul 2025 at 11:56, Geert Uytterhoeven [off-list ref] wrote:

quoted

On Wed, 9 Jul 2025 at 13:31, Ulf Hansson [off-list ref] wrote:

quoted

On Tue, 1 Jul 2025 at 13:47, Ulf Hansson [off-list ref] wrote:

quoted

Changes in v3:
        - Added a couple of patches to adress problems on some Renesas
        platforms. Thanks Geert and Tomi for helping out!
        - Adressed a few comments from Saravanna and Konrad.
        - Added some tested-by tags.

I decided it was time to give this a try, so I have queued this up for
v6.17 via the next branch at my pmdomain tree.

If you encounter any issues, please let me know so I can help to fix them.

Thanks for your series!  Due to holidays, I only managed to test
this very recently.

Unfortunately I have an issue with unused PM Domains no longer being
disabled on R-Car:
  - On R-Car Gen1/2/3, using rcar-sysc.c, unused PM Domains are never
    disabled.
  - On R-Car Gen4, using rcar-gen4-sysc.c, unused PM Domains are
    sometimes not disabled.
    At first, I noticed the IOMMU driver was not enabled in my config,
    and enabling it did fix the issue.  However, after that I still
    encountered the issue in a different config that does have the
    IOMMU driver enabled...

FTR, unused PM Domains are still disabled correctly on R/SH-Mobile
(using rmobile-sysc.c) and on BeagleBone Black. Note that these use
of_genpd_add_provider_simple(), while all R-Car drivers use
of_genpd_add_provider_onecell().  Perhaps there is an issue with
the latter?  If you don't have a clue, I plan to do some more
investigation later...

of_genpd_add_provider_onecell() has:

    if (!dev)
            sync_state = true;
    else
            dev_set_drv_sync_state(dev, genpd_sync_state);

    for (i = 0; i < data->num_domains; i++) {
            ...
            if (sync_state && !genpd_is_no_sync_state(genpd)) {
                    genpd->sync_state = GENPD_SYNC_STATE_ONECELL;
                    device_set_node(&genpd->dev, fwnode);
                    sync_state = false;
                    ^^^^^^^^^^^^^^^^^^^
            }
            ...
    }

As the R-Car SYSC drivers are not platform drivers, dev is NULL, and
genpd->sync_state is set to GENPD_SYNC_STATE_ONECELL for the first PM
Domain only.  All other domains have the default value of sync_state
(0 = GENPD_SYNC_STATE_OFF).  Hence when genpd_provider_sync_state()
is called later, it ignores all but the first domain.
Apparently this is intentional, as of_genpd_sync_state() tries to
power off all domains handled by the same controller anyway (see below)?

quoted

quoted

BTW, the "pending due to"-messages look weird to me.
On R-Car M2-W (r8a7791.dtsi) I see e.g.:

    genpd_provider ca15-cpu0: sync_state() pending due to e6020000.watchdog
    renesas-cpg-mssr e6150000.clock-controller: sync_state() pending
due to e6020000.watchdog

ca15-cpu0 is the PM Domain holding the first CPU core, while
the watchdog resides in the always-on Clock Domain, and uses the
clock-controller for PM_CLK handling.

Unfortunately the first PM Domain is "ca15-cpu0", which is blocked on
these bogus pending states, and no PM Domain is powered off.

Hi Geert,

Thanks for all the reports as ever!

Can you explain why you call these as bogus? Sorry if you already
explained it. But the reason I'm asking is to see if you can set a
flag for the watchdog device so fw_devlink will completely ignore it.

It looks like there's a driver for this watchdog node? Why is it not
probing then?

If I remove the "sync_state = false" above, genpd_provider_sync_state()
considers all domains, and does power down all unused domains (even
multiple times, as expected).

Upon closer look, all "pending due to" messages I see claim that the
first (index 0) PM Domain is pending on some devices, while all of
these devices are part of a different domain (usually the always-on
domain, which is always the last (32 or 64) on R-Car).

So I think there are two issues:
  1. Devices are not attributed to the correct PM Domain using
     fw_devlink sync_state,

Is it a fw_devlink issue? Or is this a multi-domain controller?

  2. One PM Domain of a multi-domain controller being blocked should
     not block all other domains handled by the same controller.

This is going to take a while to sort out. But the current behavior is
the safest. How grumpy will you be if we don't fix this :)

Thanks,
Saravana