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-rw-r--r--drivers/base/power/domain.c144
-rw-r--r--include/linux/pm_domain.h3
2 files changed, 102 insertions, 45 deletions
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index d06f3bb..7e6cc8a 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -44,7 +44,8 @@ static void genpd_acquire_lock(struct generic_pm_domain *genpd)
for (;;) {
prepare_to_wait(&genpd->status_wait_queue, &wait,
TASK_UNINTERRUPTIBLE);
- if (genpd->status != GPD_STATE_BUSY)
+ if (genpd->status == GPD_STATE_ACTIVE
+ || genpd->status == GPD_STATE_POWER_OFF)
break;
mutex_unlock(&genpd->lock);
@@ -60,6 +61,12 @@ static void genpd_release_lock(struct generic_pm_domain *genpd)
mutex_unlock(&genpd->lock);
}
+static void genpd_set_active(struct generic_pm_domain *genpd)
+{
+ if (genpd->resume_count == 0)
+ genpd->status = GPD_STATE_ACTIVE;
+}
+
/**
* pm_genpd_poweron - Restore power to a given PM domain and its parents.
* @genpd: PM domain to power up.
@@ -75,42 +82,24 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd)
start:
if (parent) {
- mutex_lock(&parent->lock);
+ genpd_acquire_lock(parent);
mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
} else {
mutex_lock(&genpd->lock);
}
- /*
- * Wait for the domain to transition into either the active,
- * or the power off state.
- */
- for (;;) {
- prepare_to_wait(&genpd->status_wait_queue, &wait,
- TASK_UNINTERRUPTIBLE);
- if (genpd->status != GPD_STATE_BUSY)
- break;
- mutex_unlock(&genpd->lock);
- if (parent)
- mutex_unlock(&parent->lock);
-
- schedule();
-
- if (parent) {
- mutex_lock(&parent->lock);
- mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
- } else {
- mutex_lock(&genpd->lock);
- }
- }
- finish_wait(&genpd->status_wait_queue, &wait);
if (genpd->status == GPD_STATE_ACTIVE
|| (genpd->prepared_count > 0 && genpd->suspend_power_off))
goto out;
+ if (genpd->status != GPD_STATE_POWER_OFF) {
+ genpd_set_active(genpd);
+ goto out;
+ }
+
if (parent && parent->status != GPD_STATE_ACTIVE) {
mutex_unlock(&genpd->lock);
- mutex_unlock(&parent->lock);
+ genpd_release_lock(parent);
ret = pm_genpd_poweron(parent);
if (ret)
@@ -125,14 +114,14 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd)
goto out;
}
- genpd->status = GPD_STATE_ACTIVE;
+ genpd_set_active(genpd);
if (parent)
parent->sd_count++;
out:
mutex_unlock(&genpd->lock);
if (parent)
- mutex_unlock(&parent->lock);
+ genpd_release_lock(parent);
return ret;
}
@@ -210,6 +199,20 @@ static void __pm_genpd_restore_device(struct dev_list_entry *dle,
}
/**
+ * genpd_abort_poweroff - Check if a PM domain power off should be aborted.
+ * @genpd: PM domain to check.
+ *
+ * Return true if a PM domain's status changed to GPD_STATE_ACTIVE during
+ * a "power off" operation, which means that a "power on" has occured in the
+ * meantime, or if its resume_count field is different from zero, which means
+ * that one of its devices has been resumed in the meantime.
+ */
+static bool genpd_abort_poweroff(struct generic_pm_domain *genpd)
+{
+ return genpd->status == GPD_STATE_ACTIVE || genpd->resume_count > 0;
+}
+
+/**
* pm_genpd_poweroff - Remove power from a given PM domain.
* @genpd: PM domain to power down.
*
@@ -223,9 +226,17 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
struct generic_pm_domain *parent;
struct dev_list_entry *dle;
unsigned int not_suspended;
- int ret;
+ int ret = 0;
- if (genpd->status == GPD_STATE_POWER_OFF || genpd->prepared_count > 0)
+ start:
+ /*
+ * 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.
+ * (3) One of the domain's devices is being resumed right now.
+ */
+ if (genpd->status == GPD_STATE_POWER_OFF || genpd->prepared_count > 0
+ || genpd->resume_count > 0)
return 0;
if (genpd->sd_count > 0)
@@ -239,34 +250,54 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
if (not_suspended > genpd->in_progress)
return -EBUSY;
+ if (genpd->poweroff_task) {
+ /*
+ * Another instance of pm_genpd_poweroff() is executing
+ * callbacks, so tell it to start over and return.
+ */
+ genpd->status = GPD_STATE_REPEAT;
+ return 0;
+ }
+
if (genpd->gov && genpd->gov->power_down_ok) {
if (!genpd->gov->power_down_ok(&genpd->domain))
return -EAGAIN;
}
genpd->status = GPD_STATE_BUSY;
+ genpd->poweroff_task = current;
list_for_each_entry_reverse(dle, &genpd->dev_list, node) {
ret = __pm_genpd_save_device(dle, genpd);
if (ret)
goto err_dev;
- }
- mutex_unlock(&genpd->lock);
+ if (genpd_abort_poweroff(genpd))
+ goto out;
+
+ if (genpd->status == GPD_STATE_REPEAT) {
+ genpd->poweroff_task = NULL;
+ goto start;
+ }
+ }
parent = genpd->parent;
if (parent) {
+ mutex_unlock(&genpd->lock);
+
genpd_acquire_lock(parent);
mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
- } else {
- mutex_lock(&genpd->lock);
+
+ if (genpd_abort_poweroff(genpd)) {
+ genpd_release_lock(parent);
+ goto out;
+ }
}
if (genpd->power_off)
genpd->power_off(genpd);
genpd->status = GPD_STATE_POWER_OFF;
- wake_up_all(&genpd->status_wait_queue);
if (parent) {
genpd_sd_counter_dec(parent);
@@ -276,16 +307,17 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
genpd_release_lock(parent);
}
- return 0;
+ out:
+ genpd->poweroff_task = NULL;
+ wake_up_all(&genpd->status_wait_queue);
+ return ret;
err_dev:
list_for_each_entry_continue(dle, &genpd->dev_list, node)
__pm_genpd_restore_device(dle, genpd);
- genpd->status = GPD_STATE_ACTIVE;
- wake_up_all(&genpd->status_wait_queue);
-
- return ret;
+ genpd_set_active(genpd);
+ goto out;
}
/**
@@ -327,11 +359,11 @@ static int pm_genpd_runtime_suspend(struct device *dev)
return ret;
}
- genpd_acquire_lock(genpd);
+ mutex_lock(&genpd->lock);
genpd->in_progress++;
pm_genpd_poweroff(genpd);
genpd->in_progress--;
- genpd_release_lock(genpd);
+ mutex_unlock(&genpd->lock);
return 0;
}
@@ -365,6 +397,7 @@ static void __pm_genpd_runtime_resume(struct device *dev,
static int pm_genpd_runtime_resume(struct device *dev)
{
struct generic_pm_domain *genpd;
+ DEFINE_WAIT(wait);
int ret;
dev_dbg(dev, "%s()\n", __func__);
@@ -377,12 +410,31 @@ static int pm_genpd_runtime_resume(struct device *dev)
if (ret)
return ret;
- genpd_acquire_lock(genpd);
+ mutex_lock(&genpd->lock);
genpd->status = GPD_STATE_BUSY;
+ genpd->resume_count++;
+ for (;;) {
+ prepare_to_wait(&genpd->status_wait_queue, &wait,
+ TASK_UNINTERRUPTIBLE);
+ /*
+ * If current is the powering off task, we have been called
+ * reentrantly from one of the device callbacks, so we should
+ * not wait.
+ */
+ if (!genpd->poweroff_task || genpd->poweroff_task == current)
+ break;
+ mutex_unlock(&genpd->lock);
+
+ schedule();
+
+ mutex_lock(&genpd->lock);
+ }
+ finish_wait(&genpd->status_wait_queue, &wait);
__pm_genpd_runtime_resume(dev, genpd);
- genpd->status = GPD_STATE_ACTIVE;
+ genpd->resume_count--;
+ genpd_set_active(genpd);
wake_up_all(&genpd->status_wait_queue);
- genpd_release_lock(genpd);
+ mutex_unlock(&genpd->lock);
if (genpd->start_device)
genpd->start_device(dev);
@@ -1130,6 +1182,8 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
genpd->sd_count = 0;
genpd->status = is_off ? GPD_STATE_POWER_OFF : GPD_STATE_ACTIVE;
init_waitqueue_head(&genpd->status_wait_queue);
+ genpd->poweroff_task = NULL;
+ genpd->resume_count = 0;
genpd->device_count = 0;
genpd->suspended_count = 0;
genpd->domain.ops.runtime_suspend = pm_genpd_runtime_suspend;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index c71457c..feb80af 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -14,6 +14,7 @@
enum gpd_status {
GPD_STATE_ACTIVE = 0, /* PM domain is active */
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 */
};
@@ -34,6 +35,8 @@ struct generic_pm_domain {
unsigned int sd_count; /* Number of subdomains with power "on" */
enum gpd_status status; /* Current state of the domain */
wait_queue_head_t status_wait_queue;
+ struct task_struct *poweroff_task; /* Powering off task */
+ unsigned int resume_count; /* Number of devices being resumed */
unsigned int device_count; /* Number of devices */
unsigned int suspended_count; /* System suspend device counter */
unsigned int prepared_count; /* Suspend counter of prepared devices */
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