mbox series

[00/11] pmdomain: Add generic ->sync_state() support to genpd

Message ID 20250417142513.312939-1-ulf.hansson@linaro.org (mailing list archive)
Headers show
Series pmdomain: Add generic ->sync_state() support to genpd | expand

Message

Ulf Hansson April 17, 2025, 2:24 p.m. UTC
If a PM domain (genpd) is powered-on during boot, there is probably a good
reason for it. Therefore it's known to be a bad idea to allow such genpd to be
powered-off before all of its consumer devices have been probed. This series
intends to fix this problem.

We have been discussing these issues at LKML and at various Linux-conferences
in the past. I have therefore tried to include the people I can recall being
involved, but I may have forgotten some (my apologies), feel free to loop them
in.

A few notes:
*)
Even if this looks good, the last patch can't go in without some additional
changes to a couple of existing genpd provider drivers. Typically genpd provider
drivers that implements ->sync_state() need to call of_genpd_sync_state(), but I
will fix this asap, if we think the series makes sense.

*)
Patch 1 -> 3 are just preparatory cleanups. 

*)
I have tested this with QEMU with a bunch of local test-drivers and DT nodes.
Let me know if you want me to share this code too.


Please help review and test!
Finally, a big thanks to Saravana for all the support!

Kind regards
Ulf Hansson


Saravana Kannan (1):
  driver core: Add dev_set_drv_sync_state()

Ulf Hansson (10):
  pmdomain: core: Convert genpd_power_off() to void
  pmdomain: core: Simplify return statement in genpd_power_off()
  pmdomain: core: Use genpd->opp_table to simplify error/remove path
  pmdomain: core: Add a bus and a driver for genpd providers
  pmdomain: core: Use device_set_node() to assign the fwnode too
  pmdomain: core: Add the genpd->dev to the genpd provider bus
  pmdomain: core: Export a common ->sync_state() helper for genpd
    providers
  pmdomain: core: Add internal ->sync_state() support for genpd
    providers
  pmdomain: core: Default to use of_genpd_sync_state() for genpd
    providers
  pmdomain: core: Leave powered-on genpds on until ->sync_state()

 drivers/pmdomain/core.c   | 273 +++++++++++++++++++++++++++++++-------
 include/linux/device.h    |  12 ++
 include/linux/pm_domain.h |  11 ++
 3 files changed, 249 insertions(+), 47 deletions(-)

Comments

Saravana Kannan April 18, 2025, 12:53 a.m. UTC | #1
On Thu, Apr 17, 2025 at 7:25 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> If a PM domain (genpd) is powered-on during boot, there is probably a good
> reason for it. Therefore it's known to be a bad idea to allow such genpd to be
> powered-off before all of its consumer devices have been probed. This series
> intends to fix this problem.
>
> We have been discussing these issues at LKML and at various Linux-conferences
> in the past. I have therefore tried to include the people I can recall being
> involved, but I may have forgotten some (my apologies), feel free to loop them
> in.
>
> A few notes:
> *)
> Even if this looks good, the last patch can't go in without some additional
> changes to a couple of existing genpd provider drivers. Typically genpd provider
> drivers that implements ->sync_state() need to call of_genpd_sync_state(), but I
> will fix this asap, if we think the series makes sense.
>
> *)
> Patch 1 -> 3 are just preparatory cleanups.
>
> *)
> I have tested this with QEMU with a bunch of local test-drivers and DT nodes.
> Let me know if you want me to share this code too.
>
>
> Please help review and test!
> Finally, a big thanks to Saravana for all the support!

You are welcome! Thank you for getting this series done! Happy to see
sync_state() support being added to another framework.

I skimmed the series and at a high level it looks right. Not too
familiar with power domain code, so I didn't go deep. Just reviewed
the fw_devlink and driver core parts of it.

-Saravana

>
> Kind regards
> Ulf Hansson
>
>
> Saravana Kannan (1):
>   driver core: Add dev_set_drv_sync_state()
>
> Ulf Hansson (10):
>   pmdomain: core: Convert genpd_power_off() to void
>   pmdomain: core: Simplify return statement in genpd_power_off()
>   pmdomain: core: Use genpd->opp_table to simplify error/remove path
>   pmdomain: core: Add a bus and a driver for genpd providers
>   pmdomain: core: Use device_set_node() to assign the fwnode too
>   pmdomain: core: Add the genpd->dev to the genpd provider bus
>   pmdomain: core: Export a common ->sync_state() helper for genpd
>     providers
>   pmdomain: core: Add internal ->sync_state() support for genpd
>     providers
>   pmdomain: core: Default to use of_genpd_sync_state() for genpd
>     providers
>   pmdomain: core: Leave powered-on genpds on until ->sync_state()
>
>  drivers/pmdomain/core.c   | 273 +++++++++++++++++++++++++++++++-------
>  include/linux/device.h    |  12 ++
>  include/linux/pm_domain.h |  11 ++
>  3 files changed, 249 insertions(+), 47 deletions(-)
>
> --
> 2.43.0
>