From: Rafael J. Wysocki Date: Mon, 8 Aug 2011 21:43:29 +0000 (+0200) Subject: PM / Domains: Add "wait for parent" status for generic PM domains X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3f241775c30365c33a0d2f6d40f4cf12470f48c6;p=linux-beck.git 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: Rafael J. Wysocki --- diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index dc423a99c67c..1f4b1326c6a9 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -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 (;;) { diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 81c5782d90a3..97e3f8eb4978 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -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 */