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PM / Domains: Add "wait for parent" status for generic PM domains

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The next patch will make it possible for a generic PM domain to have
multiple parents (i.e. multiple PM domains it depends on).  To
prepare for that change it is necessary to change pm_genpd_poweron()
so that it doesn't jump to the start label after running itself
recursively for the parent domain.  For this purpose, introduce a new
PM domain status value GPD_STATE_WAIT_PARENT that will be set by
pm_genpd_poweron() before calling itself recursively for the parent
domain and modify the code in drivers/base/power/domain.c so that
the GPD_STATE_WAIT_PARENT status is guaranteed to be preserved during
the execution of pm_genpd_poweron() for the parent.

This change also causes pm_genpd_add_subdomain() and
pm_genpd_remove_subdomain() to wait for started pm_genpd_poweron() to
complete and allows pm_genpd_runtime_resume() to avoid dropping the
lock after powering on the PM domain.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2011-08-08 23:43:29 +02:00
parent 9e08cf4296
commit 3f241775c3
2 changed files with 61 additions and 30 deletions
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90
drivers/base/power/domain.c
View File

@ -81,45 +81,59 @@ static void genpd_set_active(struct generic_pm_domain *genpd)
}
/**
* pm_genpd_poweron - Restore power to a given PM domain and its parents.
* __pm_genpd_poweron - Restore power to a given PM domain and its parents.
* @genpd: PM domain to power up.
*
* Restore power to @genpd and all of its parents so that it is possible to
* resume a device belonging to it.
*/
int pm_genpd_poweron(struct generic_pm_domain *genpd)
int __pm_genpd_poweron(struct generic_pm_domain *genpd)
__releases(&genpd->lock) __acquires(&genpd->lock)
{
struct generic_pm_domain *parent;
DEFINE_WAIT(wait);
int ret = 0;
mutex_lock(&genpd->lock);
/* If the domain's parent is being waited for, we have to wait too. */
for (;;) {
prepare_to_wait(&genpd->status_wait_queue, &wait,
TASK_UNINTERRUPTIBLE);
if (genpd->status != GPD_STATE_WAIT_PARENT)
break;
mutex_unlock(&genpd->lock);
parent = genpd->parent;
schedule();
mutex_lock(&genpd->lock);
}
finish_wait(&genpd->status_wait_queue, &wait);
start:
if (genpd->status == GPD_STATE_ACTIVE
|| (genpd->prepared_count > 0 && genpd->suspend_power_off))
goto out;
return 0;
if (genpd->status != GPD_STATE_POWER_OFF) {
genpd_set_active(genpd);
goto out;
return 0;
}
if (parent) {
genpd_sd_counter_inc(parent);
if (genpd->parent) {
genpd_sd_counter_inc(genpd->parent);
genpd->status = GPD_STATE_WAIT_PARENT;
mutex_unlock(&genpd->lock);
ret = pm_genpd_poweron(parent);
ret = pm_genpd_poweron(genpd->parent);
mutex_lock(&genpd->lock);
/*
* The "wait for parent" status is guaranteed not to change
* while the parent is powering on.
*/
genpd->status = GPD_STATE_POWER_OFF;
wake_up_all(&genpd->status_wait_queue);
if (ret)
goto err;
parent = NULL;
goto start;
}
if (genpd->power_on) {
@ -130,16 +144,27 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd)
genpd_set_active(genpd);
out:
mutex_unlock(&genpd->lock);
return ret;
return 0;
err:
if (genpd->parent)
genpd_sd_counter_dec(genpd->parent);
goto out;
return ret;
}
/**
* pm_genpd_poweron - Restore power to a given PM domain and its parents.
* @genpd: PM domain to power up.
*/
int pm_genpd_poweron(struct generic_pm_domain *genpd)
{
int ret;
mutex_lock(&genpd->lock);
ret = __pm_genpd_poweron(genpd);
mutex_unlock(&genpd->lock);
return ret;
}
#endif /* CONFIG_PM */
@ -225,7 +250,8 @@ static void __pm_genpd_restore_device(struct dev_list_entry *dle,
*/
static bool genpd_abort_poweroff(struct generic_pm_domain *genpd)
{
return genpd->status == GPD_STATE_ACTIVE || genpd->resume_count > 0;
return genpd->status == GPD_STATE_WAIT_PARENT
|| genpd->status == GPD_STATE_ACTIVE || genpd->resume_count > 0;
}
/**
@ -261,11 +287,13 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
/*
* Do not try to power off the domain in the following situations:
* (1) The domain is already in the "power off" state.
* (2) System suspend is in progress.
* (2) The domain is waiting for its parent to power up.
* (3) One of the domain's devices is being resumed right now.
* (4) System suspend is in progress.
*/
if (genpd->status == GPD_STATE_POWER_OFF || genpd->prepared_count > 0
|| genpd->resume_count > 0)
if (genpd->status == GPD_STATE_POWER_OFF
|| genpd->status == GPD_STATE_WAIT_PARENT
|| genpd->resume_count > 0 || genpd->prepared_count > 0)
return 0;
if (atomic_read(&genpd->sd_count) > 0)
@ -299,14 +327,15 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
list_for_each_entry_reverse(dle, &genpd->dev_list, node) {
ret = atomic_read(&genpd->sd_count) == 0 ?
__pm_genpd_save_device(dle, genpd) : -EBUSY;
if (genpd_abort_poweroff(genpd))
goto out;
if (ret) {
genpd_set_active(genpd);
goto out;
}
if (genpd_abort_poweroff(genpd))
goto out;
if (genpd->status == GPD_STATE_REPEAT) {
genpd->poweroff_task = NULL;
goto start;
@ -432,11 +461,12 @@ static int pm_genpd_runtime_resume(struct device *dev)
if (IS_ERR(genpd))
return -EINVAL;
ret = pm_genpd_poweron(genpd);
if (ret)
return ret;
mutex_lock(&genpd->lock);
ret = __pm_genpd_poweron(genpd);
if (ret) {
mutex_unlock(&genpd->lock);
return ret;
}
genpd->status = GPD_STATE_BUSY;
genpd->resume_count++;
for (;;) {

1
include/linux/pm_domain.h
View File

@ -13,6 +13,7 @@
enum gpd_status {
GPD_STATE_ACTIVE = 0, /* PM domain is active */
GPD_STATE_WAIT_PARENT, /* PM domain's parent is being waited for */
GPD_STATE_BUSY, /* Something is happening to the PM domain */
GPD_STATE_REPEAT, /* Power off in progress, to be repeated */
GPD_STATE_POWER_OFF, /* PM domain is off */