From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
Restart devices (e.g., watchdog) may be part of a software-controlled power
domain. In the case of watchdog devices, if they implement the
struct watchdog::restart() API, this is called though:
kernel_restart() ->
machine_restart() ->
do_kernel_restart() ->
atomic_notifier_call_chain() ->
watchdog_restart_notifier()
The watchdog_restart_notifier() is called with local interrupts disabled
and SMP disabled (machine_restart() calls local_irq_disable() and
smp_send_stop() before calling do_kernel_restart()).
If the restart device (e.g., watchdog) is part of a software-controlled
power domain and this domain is off at the moment of restart, we need to
power it on before configuring the watchdog device.
Add the dev_pm_genpd_resume_restart_dev() function to power on a restart
device in these scenarios.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
---
drivers/pmdomain/core.c | 18 ++++++++++++++++++
include/linux/pm_domain.h | 2 ++
2 files changed, 20 insertions(+)
diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 83d978743659..d05bd72f6cfe 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -1540,6 +1540,24 @@ void dev_pm_genpd_resume(struct device *dev)
}
EXPORT_SYMBOL_GPL(dev_pm_genpd_resume);
+/**
+ * dev_pm_genpd_resume_restart_dev - Try to synchronously resume the genpd for
+ * a reset device
+ * @dev: The reset device that is attached to the genpd, which needs to be
+ * resumed.
+ *
+ * This routine should tipicaly be called for a restart device (e.g. watchdog)
+ * that needs to be resumed during system restart phase.
+ */
+void dev_pm_genpd_resume_restart_dev(struct device *dev)
+{
+ if (system_state != SYSTEM_RESTART)
+ return;
+
+ dev_pm_genpd_resume(dev);
+}
+EXPORT_SYMBOL_GPL(dev_pm_genpd_resume_restart_dev);
+
#else /* !CONFIG_PM_SLEEP */
#define genpd_prepare NULL
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 71e4f0fb8867..9f8ecfa0bf3c 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -347,9 +347,11 @@ static inline void dev_pm_genpd_synced_poweroff(struct device *dev)
#ifdef CONFIG_PM_GENERIC_DOMAINS_SLEEP
void dev_pm_genpd_suspend(struct device *dev);
void dev_pm_genpd_resume(struct device *dev);
+void dev_pm_genpd_resume_restart_dev(struct device *dev);
#else
static inline void dev_pm_genpd_suspend(struct device *dev) {}
static inline void dev_pm_genpd_resume(struct device *dev) {}
+static inline void dev_pm_genpd_resume_restart_dev(struct device *dev) {}
#endif
/* OF PM domain providers */
--
2.39.2
