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PM / Domains: Introduce simplified power on routine for system resume

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Introduce function pm_genpd_sync_poweron() for restoring domain power
during resume from system suspend and hibernation.  It can be much
simpler than pm_genpd_poweron(), because it doesn't have to care
about locking and it can skip many checks done by the latter.

Modify pm_genpd_resume_noirq() and pm_genpd_restore_noirq() to use
the new function.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki
2012-08-06 01:39:16 +02:00
parent 4cbe5a555f
commit 802d8b49a7
1 changed files with 30 additions and 4 deletions
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34
drivers/base/power/domain.c
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@ -776,6 +776,32 @@ static void pm_genpd_sync_poweroff(struct generic_pm_domain *genpd)
}
}
/**
* pm_genpd_sync_poweron - Synchronously power on a PM domain and its masters.
* @genpd: PM domain to power on.
*
* This function is only called in "noirq" stage of system power transitions, so
* it need not acquire locks (all of the "noirq" callbacks are executed
* sequentially, so it is guaranteed that it will never run twice in parallel).
*/
static void pm_genpd_sync_poweron(struct generic_pm_domain *genpd)
{
struct gpd_link *link;
if (genpd->status != GPD_STATE_POWER_OFF)
return;
list_for_each_entry(link, &genpd->slave_links, slave_node) {
pm_genpd_sync_poweron(link->master);
genpd_sd_counter_inc(link->master);
}
if (genpd->power_on)
genpd->power_on(genpd);
genpd->status = GPD_STATE_ACTIVE;
}
/**
* resume_needed - Check whether to resume a device before system suspend.
* @dev: Device to check.
@ -979,7 +1005,7 @@ static int pm_genpd_resume_noirq(struct device *dev)
* guaranteed that this function will never run twice in parallel for
* the same PM domain, so it is not necessary to use locking here.
*/
pm_genpd_poweron(genpd);
pm_genpd_sync_poweron(genpd);
genpd->suspended_count--;
return genpd_start_dev(genpd, dev);
@ -1186,8 +1212,8 @@ static int pm_genpd_restore_noirq(struct device *dev)
if (genpd->suspended_count++ == 0) {
/*
* The boot kernel might put the domain into arbitrary state,
* so make it appear as powered off to pm_genpd_poweron(), so
* that it tries to power it on in case it was really off.
* so make it appear as powered off to pm_genpd_sync_poweron(),
* so that it tries to power it on in case it was really off.
*/
genpd->status = GPD_STATE_POWER_OFF;
if (genpd->suspend_power_off) {
@ -1205,7 +1231,7 @@ static int pm_genpd_restore_noirq(struct device *dev)
if (genpd->suspend_power_off)
return 0;
pm_genpd_poweron(genpd);
pm_genpd_sync_poweron(genpd);
return dev_gpd_data(dev)->always_on ? 0 : genpd_start_dev(genpd, dev);
}