diff options
Diffstat (limited to 'drivers/base/core.c')
-rw-r--r-- | drivers/base/core.c | 311 |
1 files changed, 301 insertions, 10 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 2db62d98e395..42a672456432 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -9,6 +9,7 @@ */ #include <linux/acpi.h> +#include <linux/cpufreq.h> #include <linux/device.h> #include <linux/err.h> #include <linux/fwnode.h> @@ -44,6 +45,10 @@ early_param("sysfs.deprecated", sysfs_deprecated_setup); #endif /* Device links support. */ +static LIST_HEAD(wait_for_suppliers); +static DEFINE_MUTEX(wfs_lock); +static LIST_HEAD(deferred_sync); +static unsigned int defer_sync_state_count = 1; #ifdef CONFIG_SRCU static DEFINE_MUTEX(device_links_lock); @@ -126,6 +131,9 @@ static int device_is_dependent(struct device *dev, void *target) return ret; list_for_each_entry(link, &dev->links.consumers, s_node) { + if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) + continue; + if (link->consumer == target) return 1; @@ -195,8 +203,11 @@ static int device_reorder_to_tail(struct device *dev, void *not_used) device_pm_move_last(dev); device_for_each_child(dev, NULL, device_reorder_to_tail); - list_for_each_entry(link, &dev->links.consumers, s_node) + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) + continue; device_reorder_to_tail(link->consumer, NULL); + } return 0; } @@ -223,7 +234,8 @@ void device_pm_move_to_tail(struct device *dev) #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ DL_FLAG_AUTOREMOVE_SUPPLIER | \ - DL_FLAG_AUTOPROBE_CONSUMER) + DL_FLAG_AUTOPROBE_CONSUMER | \ + DL_FLAG_SYNC_STATE_ONLY) #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) @@ -291,6 +303,8 @@ struct device_link *device_link_add(struct device *consumer, if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS || (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || + (flags & DL_FLAG_SYNC_STATE_ONLY && + flags != DL_FLAG_SYNC_STATE_ONLY) || (flags & DL_FLAG_AUTOPROBE_CONSUMER && flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) @@ -311,11 +325,14 @@ struct device_link *device_link_add(struct device *consumer, /* * If the supplier has not been fully registered yet or there is a - * reverse dependency between the consumer and the supplier already in - * the graph, return NULL. + * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and + * the supplier already in the graph, return NULL. If the link is a + * SYNC_STATE_ONLY link, we don't check for reverse dependencies + * because it only affects sync_state() callbacks. */ if (!device_pm_initialized(supplier) - || device_is_dependent(consumer, supplier)) { + || (!(flags & DL_FLAG_SYNC_STATE_ONLY) && + device_is_dependent(consumer, supplier))) { link = NULL; goto out; } @@ -342,9 +359,14 @@ struct device_link *device_link_add(struct device *consumer, } if (flags & DL_FLAG_STATELESS) { - link->flags |= DL_FLAG_STATELESS; kref_get(&link->kref); - goto out; + if (link->flags & DL_FLAG_SYNC_STATE_ONLY && + !(link->flags & DL_FLAG_STATELESS)) { + link->flags |= DL_FLAG_STATELESS; + goto reorder; + } else { + goto out; + } } /* @@ -366,6 +388,12 @@ struct device_link *device_link_add(struct device *consumer, link->flags |= DL_FLAG_MANAGED; device_link_init_status(link, consumer, supplier); } + if (link->flags & DL_FLAG_SYNC_STATE_ONLY && + !(flags & DL_FLAG_SYNC_STATE_ONLY)) { + link->flags &= ~DL_FLAG_SYNC_STATE_ONLY; + goto reorder; + } + goto out; } @@ -405,6 +433,13 @@ struct device_link *device_link_add(struct device *consumer, flags & DL_FLAG_PM_RUNTIME) pm_runtime_resume(supplier); + if (flags & DL_FLAG_SYNC_STATE_ONLY) { + dev_dbg(consumer, + "Linked as a sync state only consumer to %s\n", + dev_name(supplier)); + goto out; + } +reorder: /* * Move the consumer and all of the devices depending on it to the end * of dpm_list and the devices_kset list. @@ -430,6 +465,70 @@ struct device_link *device_link_add(struct device *consumer, } EXPORT_SYMBOL_GPL(device_link_add); +/** + * device_link_wait_for_supplier - Add device to wait_for_suppliers list + * @consumer: Consumer device + * + * Marks the @consumer device as waiting for suppliers to become available by + * adding it to the wait_for_suppliers list. The consumer device will never be + * probed until it's removed from the wait_for_suppliers list. + * + * The caller is responsible for adding the links to the supplier devices once + * they are available and removing the @consumer device from the + * wait_for_suppliers list once links to all the suppliers have been created. + * + * This function is NOT meant to be called from the probe function of the + * consumer but rather from code that creates/adds the consumer device. + */ +static void device_link_wait_for_supplier(struct device *consumer, + bool need_for_probe) +{ + mutex_lock(&wfs_lock); + list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers); + consumer->links.need_for_probe = need_for_probe; + mutex_unlock(&wfs_lock); +} + +static void device_link_wait_for_mandatory_supplier(struct device *consumer) +{ + device_link_wait_for_supplier(consumer, true); +} + +static void device_link_wait_for_optional_supplier(struct device *consumer) +{ + device_link_wait_for_supplier(consumer, false); +} + +/** + * device_link_add_missing_supplier_links - Add links from consumer devices to + * supplier devices, leaving any + * consumer with inactive suppliers on + * the wait_for_suppliers list + * + * Loops through all consumers waiting on suppliers and tries to add all their + * supplier links. If that succeeds, the consumer device is removed from + * wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers + * list. Devices left on the wait_for_suppliers list will not be probed. + * + * The fwnode add_links callback is expected to return 0 if it has found and + * added all the supplier links for the consumer device. It should return an + * error if it isn't able to do so. + * + * The caller of device_link_wait_for_supplier() is expected to call this once + * it's aware of potential suppliers becoming available. + */ +static void device_link_add_missing_supplier_links(void) +{ + struct device *dev, *tmp; + + mutex_lock(&wfs_lock); + list_for_each_entry_safe(dev, tmp, &wait_for_suppliers, + links.needs_suppliers) + if (!fwnode_call_int_op(dev->fwnode, add_links, dev)) + list_del_init(&dev->links.needs_suppliers); + mutex_unlock(&wfs_lock); +} + static void device_link_free(struct device_link *link) { while (refcount_dec_not_one(&link->rpm_active)) @@ -564,10 +663,23 @@ int device_links_check_suppliers(struct device *dev) struct device_link *link; int ret = 0; + /* + * Device waiting for supplier to become available is not allowed to + * probe. + */ + mutex_lock(&wfs_lock); + if (!list_empty(&dev->links.needs_suppliers) && + dev->links.need_for_probe) { + mutex_unlock(&wfs_lock); + return -EPROBE_DEFER; + } + mutex_unlock(&wfs_lock); + device_links_write_lock(); list_for_each_entry(link, &dev->links.suppliers, c_node) { - if (!(link->flags & DL_FLAG_MANAGED)) + if (!(link->flags & DL_FLAG_MANAGED) || + link->flags & DL_FLAG_SYNC_STATE_ONLY) continue; if (link->status != DL_STATE_AVAILABLE) { @@ -584,6 +696,128 @@ int device_links_check_suppliers(struct device *dev) } /** + * __device_links_queue_sync_state - Queue a device for sync_state() callback + * @dev: Device to call sync_state() on + * @list: List head to queue the @dev on + * + * Queues a device for a sync_state() callback when the device links write lock + * isn't held. This allows the sync_state() execution flow to use device links + * APIs. The caller must ensure this function is called with + * device_links_write_lock() held. + * + * This function does a get_device() to make sure the device is not freed while + * on this list. + * + * So the caller must also ensure that device_links_flush_sync_list() is called + * as soon as the caller releases device_links_write_lock(). This is necessary + * to make sure the sync_state() is called in a timely fashion and the + * put_device() is called on this device. + */ +static void __device_links_queue_sync_state(struct device *dev, + struct list_head *list) +{ + 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; + } + + /* + * Set the flag here to avoid adding the same device to a list more + * than once. This can happen if new consumers get added to the device + * and probed before the list is flushed. + */ + dev->state_synced = true; + + if (WARN_ON(!list_empty(&dev->links.defer_sync))) + return; + + get_device(dev); + list_add_tail(&dev->links.defer_sync, list); +} + +/** + * device_links_flush_sync_list - Call sync_state() on a list of devices + * @list: List of devices to call sync_state() on + * + * Calls sync_state() on all the devices that have been queued for it. This + * function is used in conjunction with __device_links_queue_sync_state(). + */ +static void device_links_flush_sync_list(struct list_head *list) +{ + struct device *dev, *tmp; + + list_for_each_entry_safe(dev, tmp, list, links.defer_sync) { + list_del_init(&dev->links.defer_sync); + + device_lock(dev); + + if (dev->bus->sync_state) + dev->bus->sync_state(dev); + else if (dev->driver && dev->driver->sync_state) + dev->driver->sync_state(dev); + + device_unlock(dev); + + put_device(dev); + } +} + +void device_links_supplier_sync_state_pause(void) +{ + device_links_write_lock(); + defer_sync_state_count++; + device_links_write_unlock(); +} + +void device_links_supplier_sync_state_resume(void) +{ + struct device *dev, *tmp; + LIST_HEAD(sync_list); + + device_links_write_lock(); + if (!defer_sync_state_count) { + WARN(true, "Unmatched sync_state pause/resume!"); + goto out; + } + defer_sync_state_count--; + if (defer_sync_state_count) + goto out; + + list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) { + /* + * Delete from deferred_sync list before queuing it to + * sync_list because defer_sync is used for both lists. + */ + list_del_init(&dev->links.defer_sync); + __device_links_queue_sync_state(dev, &sync_list); + } +out: + device_links_write_unlock(); + + device_links_flush_sync_list(&sync_list); +} + +static int sync_state_resume_initcall(void) +{ + device_links_supplier_sync_state_resume(); + return 0; +} +late_initcall(sync_state_resume_initcall); + +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. * @@ -597,6 +831,16 @@ int device_links_check_suppliers(struct device *dev) void device_links_driver_bound(struct device *dev) { struct device_link *link; + LIST_HEAD(sync_list); + + /* + * If a device probes successfully, it's expected to have created all + * the device links it needs to or make new device links as it needs + * them. So, it no longer needs to wait on any suppliers. + */ + mutex_lock(&wfs_lock); + list_del_init(&dev->links.needs_suppliers); + mutex_unlock(&wfs_lock); device_links_write_lock(); @@ -627,11 +871,19 @@ void device_links_driver_bound(struct device *dev) WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); WRITE_ONCE(link->status, DL_STATE_ACTIVE); + + if (defer_sync_state_count) + __device_links_supplier_defer_sync(link->supplier); + else + __device_links_queue_sync_state(link->supplier, + &sync_list); } dev->links.status = DL_DEV_DRIVER_BOUND; device_links_write_unlock(); + + device_links_flush_sync_list(&sync_list); } static void device_link_drop_managed(struct device_link *link) @@ -743,6 +995,7 @@ 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(); @@ -812,7 +1065,8 @@ void device_links_unbind_consumers(struct device *dev) list_for_each_entry(link, &dev->links.consumers, s_node) { enum device_link_state status; - if (!(link->flags & DL_FLAG_MANAGED)) + if (!(link->flags & DL_FLAG_MANAGED) || + link->flags & DL_FLAG_SYNC_STATE_ONLY) continue; status = link->status; @@ -848,6 +1102,10 @@ static void device_links_purge(struct device *dev) { struct device_link *link, *ln; + mutex_lock(&wfs_lock); + list_del(&dev->links.needs_suppliers); + mutex_unlock(&wfs_lock); + /* * Delete all of the remaining links from this device to any other * devices (either consumers or suppliers). @@ -1712,6 +1970,8 @@ void device_initialize(struct device *dev) #endif 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); @@ -2100,7 +2360,7 @@ int device_add(struct device *dev) struct device *parent; struct kobject *kobj; struct class_interface *class_intf; - int error = -EINVAL; + int error = -EINVAL, fw_ret; struct kobject *glue_dir = NULL; dev = get_device(dev); @@ -2198,6 +2458,32 @@ int device_add(struct device *dev) BUS_NOTIFY_ADD_DEVICE, dev); kobject_uevent(&dev->kobj, KOBJ_ADD); + + if (dev->fwnode && !dev->fwnode->dev) + dev->fwnode->dev = dev; + + /* + * Check if any of the other devices (consumers) have been waiting for + * this device (supplier) to be added so that they can create a device + * link to it. + * + * This needs to happen after device_pm_add() because device_link_add() + * requires the supplier be registered before it's called. + * + * But this also needs to happe before bus_probe_device() to make sure + * waiting consumers can link to it before the driver is bound to the + * device and the driver sync_state callback is called for this device. + */ + device_link_add_missing_supplier_links(); + + if (fwnode_has_op(dev->fwnode, add_links)) { + fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); + if (fw_ret == -ENODEV) + device_link_wait_for_mandatory_supplier(dev); + else if (fw_ret) + device_link_wait_for_optional_supplier(dev); + } + bus_probe_device(dev); if (parent) klist_add_tail(&dev->p->knode_parent, @@ -2342,6 +2628,9 @@ void device_del(struct device *dev) kill_device(dev); device_unlock(dev); + if (dev->fwnode && dev->fwnode->dev == dev) + dev->fwnode->dev = NULL; + /* Notify clients of device removal. This call must come * before dpm_sysfs_remove(). */ @@ -3179,6 +3468,8 @@ void device_shutdown(void) wait_for_device_probe(); device_block_probing(); + cpufreq_suspend(); + spin_lock(&devices_kset->list_lock); /* * Walk the devices list backward, shutting down each in turn. |