Re: [PATCH 1/2] PM / Domains: Add GENPD_FLAG_SUSPEND_ON flag

From: Sibi Sankar
Date: Wed Aug 12 2020 - 13:14:26 EST

Thanks for taking time to review the

On 2020-08-12 15:15, Ulf Hansson wrote:
On Tue, 11 Aug 2020 at 21:03, Sibi Sankar <sibis@xxxxxxxxxxxxxx> 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

Kind regards

Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
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))

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_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.