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SubjectRe: [PATCH 1/2] PM / Domains: Add GENPD_FLAG_SUSPEND_ON flag
Uffe,
Thanks for taking time to review the
series!

On 2020-08-12 15:15, Ulf Hansson wrote:
> On Tue, 11 Aug 2020 at 21:03, Sibi Sankar <sibis@codeaurora.org> wrote:
>>
>> This is for power domains which needs to stay powered on for suspend
>> but can be powered on/off as part of runtime PM. This flag is aimed at
>> power domains coupled to remote processors which enter suspend states
>> independent to that of the application processor. Such power domains
>> are turned off only on remote processor crash/shutdown.
>
> As Kevin also requested, please elaborate more on the use case.
>
> Why exactly must the PM domain stay powered on during system suspend?
> Is there a wakeup configured that needs to be managed - or is there a
> co-processor/FW behaviour that needs to be obeyed to?

Yes this is a co-processor behavior that
needs to be obeyed. Specifically application
processor notifies the Always on Subsystem
(AOSS) that a particular co-processor is up
using the power domains exposed by AOSS QMP
driver. AOSS uses this information to wait
for the co-processors to suspend before
starting its sleep sequence. The application
processor powers off these power domains only
if the co-processor has crashed or powered
off.

>
> Kind regards
> Uffe
>
>>
>> Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
>> ---
>> drivers/base/power/domain.c | 3 ++-
>> include/linux/pm_domain.h | 5 +++++
>> 2 files changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index 2cb5e04cf86cd..ba78ac4a450d4 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -129,6 +129,7 @@ static const struct genpd_lock_ops genpd_spin_ops
>> = {
>> #define genpd_is_active_wakeup(genpd) (genpd->flags &
>> GENPD_FLAG_ACTIVE_WAKEUP)
>> #define genpd_is_cpu_domain(genpd) (genpd->flags &
>> GENPD_FLAG_CPU_DOMAIN)
>> #define genpd_is_rpm_always_on(genpd) (genpd->flags &
>> GENPD_FLAG_RPM_ALWAYS_ON)
>> +#define genpd_is_suspend_on(genpd) (genpd->flags &
>> GENPD_FLAG_SUSPEND_ON)
>>
>> static inline bool irq_safe_dev_in_no_sleep_domain(struct device
>> *dev,
>> const struct generic_pm_domain *genpd)
>> @@ -949,7 +950,7 @@ static void genpd_sync_power_off(struct
>> generic_pm_domain *genpd, bool use_lock,
>> {
>> struct gpd_link *link;
>>
>> - if (!genpd_status_on(genpd) || genpd_is_always_on(genpd))
>> + if (!genpd_status_on(genpd) || genpd_is_always_on(genpd) ||
>> genpd_is_suspend_on(genpd))
>> return;
>>
>> if (genpd->suspended_count != genpd->device_count
>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>> index ee11502a575b0..3002a2d68936a 100644
>> --- a/include/linux/pm_domain.h
>> +++ b/include/linux/pm_domain.h
>> @@ -55,6 +55,10 @@
>> *
>> * GENPD_FLAG_RPM_ALWAYS_ON: Instructs genpd to always keep the PM
>> domain
>> * powered on except for system suspend.
>> + *
>> + * GENPD_FLAG_SUSPEND_ON: Instructs genpd to keep the PM domain
>> powered
>> + * on during suspend and runtime PM
>> controlled
>> + * otherwise.
>> */
>> #define GENPD_FLAG_PM_CLK (1U << 0)
>> #define GENPD_FLAG_IRQ_SAFE (1U << 1)
>> @@ -62,6 +66,7 @@
>> #define GENPD_FLAG_ACTIVE_WAKEUP (1U << 3)
>> #define GENPD_FLAG_CPU_DOMAIN (1U << 4)
>> #define GENPD_FLAG_RPM_ALWAYS_ON (1U << 5)
>> +#define GENPD_FLAG_SUSPEND_ON (1U << 6)
>>
>> enum gpd_status {
>> GPD_STATE_ACTIVE = 0, /* PM domain is active */
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum,
>> a Linux Foundation Collaborative Project
>>

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.

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