diff --git a/drivers/base/core.c b/drivers/base/core.c index feec8dee1e91..5b1795cd116a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -46,6 +46,8 @@ early_param("sysfs.deprecated", sysfs_deprecated_setup); /* Device links support. */ static LIST_HEAD(wait_for_suppliers); static DEFINE_MUTEX(wfs_lock); +static LIST_HEAD(deferred_sync); +static unsigned int supplier_sync_state_disabled; #ifdef CONFIG_SRCU static DEFINE_MUTEX(device_links_lock); @@ -651,6 +653,62 @@ int device_links_check_suppliers(struct device *dev) return ret; } +static void __device_links_supplier_sync_state(struct device *dev) +{ + struct device_link *link; + + if (dev->state_synced) + return; + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + if (link->status != DL_STATE_ACTIVE) + return; + } + + if (dev->bus->sync_state) + dev->bus->sync_state(dev); + else if (dev->driver && dev->driver->sync_state) + dev->driver->sync_state(dev); + + dev->state_synced = true; +} + +void device_links_supplier_sync_state_pause(void) +{ + device_links_write_lock(); + supplier_sync_state_disabled++; + device_links_write_unlock(); +} + +void device_links_supplier_sync_state_resume(void) +{ + struct device *dev, *tmp; + + device_links_write_lock(); + if (!supplier_sync_state_disabled) { + WARN(true, "Unmatched sync_state pause/resume!"); + goto out; + } + supplier_sync_state_disabled--; + if (supplier_sync_state_disabled) + goto out; + + list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) { + __device_links_supplier_sync_state(dev); + list_del_init(&dev->links.defer_sync); + } +out: + device_links_write_unlock(); +} + +static void __device_links_supplier_defer_sync(struct device *sup) +{ + if (list_empty(&sup->links.defer_sync)) + list_add_tail(&sup->links.defer_sync, &deferred_sync); +} + /** * device_links_driver_bound - Update device links after probing its driver. * @dev: Device to update the links for. @@ -695,6 +753,11 @@ void device_links_driver_bound(struct device *dev) WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); WRITE_ONCE(link->status, DL_STATE_ACTIVE); + + if (supplier_sync_state_disabled) + __device_links_supplier_defer_sync(link->supplier); + else + __device_links_supplier_sync_state(link->supplier); } dev->links.status = DL_DEV_DRIVER_BOUND; @@ -811,6 +874,7 @@ void device_links_driver_cleanup(struct device *dev) WRITE_ONCE(link->status, DL_STATE_DORMANT); } + list_del_init(&dev->links.defer_sync); __device_links_no_driver(dev); device_links_write_unlock(); @@ -1782,6 +1846,7 @@ void device_initialize(struct device *dev) INIT_LIST_HEAD(&dev->links.consumers); INIT_LIST_HEAD(&dev->links.suppliers); INIT_LIST_HEAD(&dev->links.needs_suppliers); + INIT_LIST_HEAD(&dev->links.defer_sync); dev->links.status = DL_DEV_NO_DRIVER; } EXPORT_SYMBOL_GPL(device_initialize); diff --git a/include/linux/device.h b/include/linux/device.h index d3991810f39d..63a3aafabcd6 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -84,6 +84,8 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *); * available at the time this function is called. As in, the * function should NOT stop at the first failed device link if * other unlinked supplier devices are present in the system. + * This is necessary for the sync_state() callback to work + * correctly. * * Return 0 if device links have been successfully created to all * the suppliers of this device. Return an error if some of the @@ -91,6 +93,13 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *); * reattempted in the future. * @probe: Called when a new device or driver add to this bus, and callback * the specific driver's probe to initial the matched device. + * @sync_state: Called to sync device state to software state after all the + * state tracking consumers linked to this device (present at + * the time of late_initcall) have successfully bound to a + * driver. If the device has no consumers, this function will + * be called at late_initcall_sync level. If the device has + * consumers that are never bound to a driver, this function + * will never get called until they do. * @remove: Called when a device removed from this bus. * @shutdown: Called at shut-down time to quiesce the device. * @@ -135,6 +144,7 @@ struct bus_type { int (*uevent)(struct device *dev, struct kobj_uevent_env *env); int (*add_links)(struct device *dev); int (*probe)(struct device *dev); + void (*sync_state)(struct device *dev); int (*remove)(struct device *dev); void (*shutdown)(struct device *dev); @@ -366,6 +376,13 @@ enum probe_type { * @probe: Called to query the existence of a specific device, * whether this driver can work with it, and bind the driver * to a specific device. + * @sync_state: Called to sync device state to software state after all the + * state tracking consumers linked to this device (present at + * the time of late_initcall) have successfully bound to a + * driver. If the device has no consumers, this function will + * be called at late_initcall_sync level. If the device has + * consumers that are never bound to a driver, this function + * will never get called until they do. * @remove: Called when the device is removed from the system to * unbind a device from this driver. * @shutdown: Called at shut-down time to quiesce the device. @@ -404,6 +421,7 @@ struct device_driver { int (*edit_links)(struct device *dev); int (*probe) (struct device *dev); + void (*sync_state)(struct device *dev); int (*remove) (struct device *dev); void (*shutdown) (struct device *dev); int (*suspend) (struct device *dev, pm_message_t state); @@ -1156,12 +1174,14 @@ enum dl_dev_state { * @suppliers: List of links to supplier devices. * @consumers: List of links to consumer devices. * @needs_suppliers: Hook to global list of devices waiting for suppliers. + * @defer_sync: Hook to global list of devices that have deferred sync_state. * @status: Driver status information. */ struct dev_links_info { struct list_head suppliers; struct list_head consumers; struct list_head needs_suppliers; + struct list_head defer_sync; enum dl_dev_state status; }; @@ -1237,6 +1257,9 @@ struct dev_links_info { * device. * @has_edit_links: This device has a driver than is capable of * editing the device links created by driver core. + * @state_synced: The hardware state of this device has been synced to match + * the software state of this device by calling the driver/bus + * sync_state() callback. * @dma_coherent: this particular device is dma coherent, even if the * architecture supports non-coherent devices. * @@ -1331,6 +1354,7 @@ struct device { bool offline:1; bool of_node_reused:1; bool has_edit_links:1; + bool state_synced:1; #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) @@ -1674,6 +1698,8 @@ struct device_link *device_link_add(struct device *consumer, void device_link_del(struct device_link *link); void device_link_remove(void *consumer, struct device *supplier); void device_link_remove_from_wfs(struct device *consumer); +void device_links_supplier_sync_state_pause(void); +void device_links_supplier_sync_state_resume(void); #ifndef dev_fmt #define dev_fmt(fmt) fmt