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PM / sleep: Make async suspend/resume of devices use device links 

Make the device suspend/resume part of the core system
suspend/resume code use device links to ensure that supplier
and consumer devices will be suspended and resumed in the right
order in case of async suspend/resume.

The idea, roughly, is to use dpm_wait() to wait for all consumers
before a supplier device suspend and to wait for all suppliers
before a consumer device resume.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rafael J. Wysocki 2016-10-30 17:28:49 +01:00 committed by Greg Kroah-Hartman
parent 9ed9895370
commit 8c73b42884
1 changed files with 79 additions and 6 deletions
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85
drivers/base/power/main.c
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@ -246,6 +246,62 @@ static void dpm_wait_for_children(struct device *dev, bool async)
device_for_each_child(dev, &async, dpm_wait_fn);
}
static void dpm_wait_for_suppliers(struct device *dev, bool async)
{
struct device_link *link;
int idx;
idx = device_links_read_lock();
/*
* If the supplier goes away right after we've checked the link to it,
* we'll wait for its completion to change the state, but that's fine,
* because the only things that will block as a result are the SRCU
* callbacks freeing the link objects for the links in the list we're
* walking.
*/
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->supplier, async);
device_links_read_unlock(idx);
}
static void dpm_wait_for_superior(struct device *dev, bool async)
{
dpm_wait(dev->parent, async);
dpm_wait_for_suppliers(dev, async);
}
static void dpm_wait_for_consumers(struct device *dev, bool async)
{
struct device_link *link;
int idx;
idx = device_links_read_lock();
/*
* The status of a device link can only be changed from "dormant" by a
* probe, but that cannot happen during system suspend/resume. In
* theory it can change to "dormant" at that time, but then it is
* reasonable to wait for the target device anyway (eg. if it goes
* away, it's better to wait for it to go away completely and then
* continue instead of trying to continue in parallel with its
* unregistration).
*/
list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->consumer, async);
device_links_read_unlock(idx);
}
static void dpm_wait_for_subordinate(struct device *dev, bool async)
{
dpm_wait_for_children(dev, async);
dpm_wait_for_consumers(dev, async);
}
/**
* pm_op - Return the PM operation appropriate for given PM event.
* @ops: PM operations to choose from.
@ -490,7 +546,7 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
if (!dev->power.is_noirq_suspended)
goto Out;
dpm_wait(dev->parent, async);
dpm_wait_for_superior(dev, async);
if (dev->pm_domain) {
info = "noirq power domain ";
@ -620,7 +676,7 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
if (!dev->power.is_late_suspended)
goto Out;
dpm_wait(dev->parent, async);
dpm_wait_for_superior(dev, async);
if (dev->pm_domain) {
info = "early power domain ";
@ -752,7 +808,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
goto Complete;
}
dpm_wait(dev->parent, async);
dpm_wait_for_superior(dev, async);
dpm_watchdog_set(&wd, dev);
device_lock(dev);
@ -1040,7 +1096,7 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
if (dev->power.syscore || dev->power.direct_complete)
goto Complete;
dpm_wait_for_children(dev, async);
dpm_wait_for_subordinate(dev, async);
if (dev->pm_domain) {
info = "noirq power domain ";
@ -1187,7 +1243,7 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
if (dev->power.syscore || dev->power.direct_complete)
goto Complete;
dpm_wait_for_children(dev, async);
dpm_wait_for_subordinate(dev, async);
if (dev->pm_domain) {
info = "late power domain ";
@ -1344,6 +1400,22 @@ static int legacy_suspend(struct device *dev, pm_message_t state,
return error;
}
static void dpm_clear_suppliers_direct_complete(struct device *dev)
{
struct device_link *link;
int idx;
idx = device_links_read_lock();
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
spin_lock_irq(&link->supplier->power.lock);
link->supplier->power.direct_complete = false;
spin_unlock_irq(&link->supplier->power.lock);
}
device_links_read_unlock(idx);
}
/**
* device_suspend - Execute "suspend" callbacks for given device.
* @dev: Device to handle.
@ -1360,7 +1432,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
TRACE_DEVICE(dev);
TRACE_SUSPEND(0);
dpm_wait_for_children(dev, async);
dpm_wait_for_subordinate(dev, async);
if (async_error)
goto Complete;
@ -1456,6 +1528,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
spin_unlock_irq(&parent->power.lock);
}
dpm_clear_suppliers_direct_complete(dev);
}
device_unlock(dev);