Commit 3f241775 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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



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: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 9e08cf42

drivers/base/power/domain.c

+60 −30
Original line number Diff line number Diff line
@@ -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 (;;) {

include/linux/pm_domain.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

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