diff options
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/core.c | 27 | ||||
| -rw-r--r-- | drivers/base/dd.c | 3 | ||||
| -rw-r--r-- | drivers/base/power/runtime.c | 157 |
3 files changed, 181 insertions, 6 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 3c5ff17f578f..876c62b12462 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -152,6 +152,14 @@ static int device_reorder_to_tail(struct device *dev, void *not_used) * @supplier: Supplier end of the link. * @flags: Link flags. * + * The caller is responsible for the proper synchronization of the link creation + * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the + * runtime PM framework to take the link into account. Second, if the + * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will + * be forced into the active metastate and reference-counted upon the creation + * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be + * ignored. + * * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically * when the consumer device driver unbinds from it. The combination of both * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL @@ -193,10 +201,19 @@ struct device_link *device_link_add(struct device *consumer, if (link->consumer == consumer) goto out; - link = kmalloc(sizeof(*link), GFP_KERNEL); + link = kzalloc(sizeof(*link), GFP_KERNEL); if (!link) goto out; + if ((flags & DL_FLAG_PM_RUNTIME) && (flags & DL_FLAG_RPM_ACTIVE)) { + if (pm_runtime_get_sync(supplier) < 0) { + pm_runtime_put_noidle(supplier); + kfree(link); + link = NULL; + goto out; + } + link->rpm_active = true; + } get_device(supplier); link->supplier = supplier; INIT_LIST_HEAD(&link->s_node); @@ -213,6 +230,14 @@ struct device_link *device_link_add(struct device *consumer, case DL_DEV_DRIVER_BOUND: switch (consumer->links.status) { case DL_DEV_PROBING: + /* + * Balance the decrementation of the supplier's + * runtime PM usage counter after consumer probe + * in driver_probe_device(). + */ + if (flags & DL_FLAG_PM_RUNTIME) + pm_runtime_get_sync(supplier); + link->status = DL_STATE_CONSUMER_PROBE; break; case DL_DEV_DRIVER_BOUND: diff --git a/drivers/base/dd.c b/drivers/base/dd.c index b2bca3cf0dd2..43be1cc751a4 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -513,6 +513,7 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); + pm_runtime_get_suppliers(dev); if (dev->parent) pm_runtime_get_sync(dev->parent); @@ -523,6 +524,7 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) if (dev->parent) pm_runtime_put(dev->parent); + pm_runtime_put_suppliers(dev); return ret; } @@ -806,6 +808,7 @@ static void __device_release_driver(struct device *dev, struct device *parent) } pm_runtime_get_sync(dev); + pm_runtime_clean_up_links(dev); driver_sysfs_remove(dev); diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 82a081ea4317..462f90e952f8 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -12,6 +12,8 @@ #include <linux/pm_runtime.h> #include <linux/pm_wakeirq.h> #include <trace/events/rpm.h> + +#include "../base.h" #include "power.h" typedef int (*pm_callback_t)(struct device *); @@ -258,6 +260,42 @@ static int rpm_check_suspend_allowed(struct device *dev) return retval; } +static int rpm_get_suppliers(struct device *dev) +{ + struct device_link *link; + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) { + int retval; + + if (!(link->flags & DL_FLAG_PM_RUNTIME)) + continue; + + if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND || + link->rpm_active) + continue; + + retval = pm_runtime_get_sync(link->supplier); + if (retval < 0) { + pm_runtime_put_noidle(link->supplier); + return retval; + } + link->rpm_active = true; + } + return 0; +} + +static void rpm_put_suppliers(struct device *dev) +{ + struct device_link *link; + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) + if (link->rpm_active && + READ_ONCE(link->status) != DL_STATE_SUPPLIER_UNBIND) { + pm_runtime_put(link->supplier); + link->rpm_active = false; + } +} + /** * __rpm_callback - Run a given runtime PM callback for a given device. * @cb: Runtime PM callback to run. @@ -266,19 +304,55 @@ static int rpm_check_suspend_allowed(struct device *dev) static int __rpm_callback(int (*cb)(struct device *), struct device *dev) __releases(&dev->power.lock) __acquires(&dev->power.lock) { - int retval; + int retval, idx; - if (dev->power.irq_safe) + if (dev->power.irq_safe) { spin_unlock(&dev->power.lock); - else + } else { spin_unlock_irq(&dev->power.lock); + /* + * Resume suppliers if necessary. + * + * The device's runtime PM status cannot change until this + * routine returns, so it is safe to read the status outside of + * the lock. + */ + if (dev->power.runtime_status == RPM_RESUMING) { + idx = device_links_read_lock(); + + retval = rpm_get_suppliers(dev); + if (retval) + goto fail; + + device_links_read_unlock(idx); + } + } + retval = cb(dev); - if (dev->power.irq_safe) + if (dev->power.irq_safe) { spin_lock(&dev->power.lock); - else + } else { + /* + * If the device is suspending and the callback has returned + * success, drop the usage counters of the suppliers that have + * been reference counted on its resume. + * + * Do that if resume fails too. + */ + if ((dev->power.runtime_status == RPM_SUSPENDING && !retval) + || (dev->power.runtime_status == RPM_RESUMING && retval)) { + idx = device_links_read_lock(); + + fail: + rpm_put_suppliers(dev); + + device_links_read_unlock(idx); + } + spin_lock_irq(&dev->power.lock); + } return retval; } @@ -1447,6 +1521,79 @@ void pm_runtime_remove(struct device *dev) } /** + * pm_runtime_clean_up_links - Prepare links to consumers for driver removal. + * @dev: Device whose driver is going to be removed. + * + * Check links from this device to any consumers and if any of them have active + * runtime PM references to the device, drop the usage counter of the device + * (once per link). + * + * Links with the DL_FLAG_STATELESS flag set are ignored. + * + * Since the device is guaranteed to be runtime-active at the point this is + * called, nothing else needs to be done here. + * + * Moreover, this is called after device_links_busy() has returned 'false', so + * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and + * therefore rpm_active can't be manipulated concurrently. + */ +void pm_runtime_clean_up_links(struct device *dev) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.consumers, s_node) { + if (link->flags & DL_FLAG_STATELESS) + continue; + + if (link->rpm_active) { + pm_runtime_put_noidle(dev); + link->rpm_active = false; + } + } + + device_links_read_unlock(idx); +} + +/** + * pm_runtime_get_suppliers - Resume and reference-count supplier devices. + * @dev: Consumer device. + */ +void pm_runtime_get_suppliers(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) + if (link->flags & DL_FLAG_PM_RUNTIME) + pm_runtime_get_sync(link->supplier); + + device_links_read_unlock(idx); +} + +/** + * pm_runtime_put_suppliers - Drop references to supplier devices. + * @dev: Consumer device. + */ +void pm_runtime_put_suppliers(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) + if (link->flags & DL_FLAG_PM_RUNTIME) + pm_runtime_put(link->supplier); + + device_links_read_unlock(idx); +} + +/** * pm_runtime_force_suspend - Force a device into suspend state if needed. * @dev: Device to suspend. * |