Re: [PATCH] firmware: psci: Set pm_set_resume/suspend_via_firmware() for SYSTEM_SUSPEND

[Manivannan Sadhasivam]

On Tue, Mar 24, 2026 at 09:44:41AM +0100, Lorenzo Pieralisi wrote:
> [+Arnd, arm-soc - to pick this up please]
> 

Arnd, could you please pick this up?

- Mani

> On Wed, Dec 31, 2025 at 09:51:26PM +0530, Manivannan Sadhasivam wrote:
> > From: Konrad Dybcio <konradybcio@xxxxxxxxxx>
> > 
> > PSCI specification defines the SYSTEM_SUSPEND feature which enables the
> > firmware to implement the suspend to RAM (S2RAM) functionality by
> > transitioning the system to a deeper low power state. When the system
> > enters such state, the power to the peripheral devices might be removed. So
> > the respective device drivers must prepare for the possible removal of the
> > power by performing actions such as shutting down or resetting the device
> > in their system suspend callbacks.
> > 
> > The Linux PM framework allows the platform drivers to convey this info to
> > device drivers by calling the pm_set_suspend_via_firmware() and
> > pm_set_resume_via_firmware() APIs.
> > 
> > Hence, if the PSCI firmware supports SYSTEM_SUSPEND feature, call the above
> > mentioned APIs in the psci_system_suspend_begin() and
> > psci_system_suspend_enter() callbacks.
> > 
> > Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> > Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > [mani: reworded the description to be more elaborative]
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
> > ---
> > 
> > This patch was part of an old series that didn't make it to mainline due to
> > objections in the binding and exposing CPU_SUSPEND as S2RAM patches:
> > https://lore.kernel.org/all/20241028-topic-cpu_suspend_s2ram-v1-0-9fdd9a04b75c@xxxxxxxxxxxxxxxx/
> > 
> > But this patch on its own is useful for platforms implementing the S2RAM
> > feature in PSCI firmware. So I picked it up, tested on Qcom X1E T14s and
> > resending it.
> > 
> >  drivers/firmware/psci/psci.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> 
> Acked-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
> 
> > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> > index 38ca190d4a22..e73bae6cb23a 100644
> > --- a/drivers/firmware/psci/psci.c
> > +++ b/drivers/firmware/psci/psci.c
> > @@ -539,12 +539,22 @@ static int psci_system_suspend(unsigned long unused)
> >  
> >  static int psci_system_suspend_enter(suspend_state_t state)
> >  {
> > +	pm_set_resume_via_firmware();
> > +
> >  	return cpu_suspend(0, psci_system_suspend);
> >  }
> >  
> > +static int psci_system_suspend_begin(suspend_state_t state)
> > +{
> > +	pm_set_suspend_via_firmware();
> > +
> > +	return 0;
> > +}
> > +
> >  static const struct platform_suspend_ops psci_suspend_ops = {
> >  	.valid          = suspend_valid_only_mem,
> >  	.enter          = psci_system_suspend_enter,
> > +	.begin          = psci_system_suspend_begin,
> >  };
> >  
> >  static void __init psci_init_system_reset2(void)
> > -- 
> > 2.48.1
> > 

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