xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

PM / Runtime: Add synchronous runtime interface for interrupt handlers (v3)

Browse Source 
This patch (as1431c) makes the synchronous runtime-PM interface
suitable for use in interrupt handlers.  Subsystems can call the new
pm_runtime_irq_safe() function to tell the PM core that a device's
runtime_suspend and runtime_resume callbacks should be invoked with
interrupts disabled and the spinlock held.  This permits the
pm_runtime_get_sync() and the new pm_runtime_put_sync_suspend()
routines to be called from within interrupt handlers.

When a device is declared irq-safe in this way, the PM core increments
the parent's usage count, so the parent will never be runtime
suspended.  This prevents difficult situations in which an irq-safe
device can't resume because it is forced to wait for its non-irq-safe
parent.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Alan Stern
2010-12-01 00:14:42 +01:00
committed by Rafael J. Wysocki
parent 5262a47502
commit c7b61de5b7
4 changed files with 77 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/base/power/runtime.c
View File

@@ -250,13 +250,16 @@ static int rpm_callback(int (*cb)(struct device *), struct device *dev)
if (!cb)
return -ENOSYS;
spin_unlock_irq(&dev->power.lock);
if (dev->power.irq_safe) {
retval = cb(dev);
} else {
spin_unlock_irq(&dev->power.lock);
retval = cb(dev);
retval = cb(dev);
spin_lock_irq(&dev->power.lock);
spin_lock_irq(&dev->power.lock);
}
dev->power.runtime_error = retval;
return retval;
}
@@ -404,7 +407,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
goto out;
}
if (parent && !parent->power.ignore_children) {
if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
spin_unlock_irq(&dev->power.lock);
pm_request_idle(parent);
@@ -527,10 +530,13 @@ static int rpm_resume(struct device *dev, int rpmflags)
if (!parent && dev->parent) {
/*
* Increment the parent's resume counter and resume it if
* necessary.
* Increment the parent's usage counter and resume it if
* necessary. Not needed if dev is irq-safe; then the
* parent is permanently resumed.
*/
parent = dev->parent;
if (dev->power.irq_safe)
goto skip_parent;
spin_unlock(&dev->power.lock);
pm_runtime_get_noresume(parent);
@@ -553,6 +559,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
goto out;
goto repeat;
}
skip_parent:
if (dev->power.no_callbacks)
goto no_callback; /* Assume success. */
@@ -584,7 +591,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
rpm_idle(dev, RPM_ASYNC);
out:
if (parent) {
if (parent && !dev->power.irq_safe) {
spin_unlock_irq(&dev->power.lock);
pm_runtime_put(parent);
@@ -1065,7 +1072,6 @@ EXPORT_SYMBOL_GPL(pm_runtime_allow);
* Set the power.no_callbacks flag, which tells the PM core that this
* device is power-managed through its parent and has no run-time PM
* callbacks of its own. The run-time sysfs attributes will be removed.
*
*/
void pm_runtime_no_callbacks(struct device *dev)
{
@@ -1077,6 +1083,27 @@ void pm_runtime_no_callbacks(struct device *dev)
}
EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
/**
* pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
* @dev: Device to handle
*
* Set the power.irq_safe flag, which tells the PM core that the
* ->runtime_suspend() and ->runtime_resume() callbacks for this device should
* always be invoked with the spinlock held and interrupts disabled. It also
* causes the parent's usage counter to be permanently incremented, preventing
* the parent from runtime suspending -- otherwise an irq-safe child might have
* to wait for a non-irq-safe parent.
*/
void pm_runtime_irq_safe(struct device *dev)
{
if (dev->parent)
pm_runtime_get_sync(dev->parent);
spin_lock_irq(&dev->power.lock);
dev->power.irq_safe = 1;
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
/**
* update_autosuspend - Handle a change to a device's autosuspend settings.
* @dev: Device to handle.
@@ -1199,4 +1226,6 @@ void pm_runtime_remove(struct device *dev)
/* Change the status back to 'suspended' to match the initial status. */
if (dev->power.runtime_status == RPM_ACTIVE)
pm_runtime_set_suspended(dev);
if (dev->power.irq_safe && dev->parent)
pm_runtime_put_sync(dev->parent);
}