diff options
| -rw-r--r-- | drivers/base/core.c | 24 | ||||
| -rw-r--r-- | drivers/base/dd.c | 29 | ||||
| -rw-r--r-- | include/linux/device.h | 20 |
3 files changed, 71 insertions, 2 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 18e04ca1de13..feec8dee1e91 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -440,6 +440,19 @@ static void device_link_wait_for_supplier(struct device *consumer) } /** + * device_link_remove_from_wfs - Unmark device as waiting for supplier + * @consumer: Consumer device + * + * Unmark the consumer device as waiting for suppliers to become available. + */ +void device_link_remove_from_wfs(struct device *consumer) +{ + mutex_lock(&wfs_lock); + list_del_init(&consumer->links.needs_suppliers); + mutex_unlock(&wfs_lock); +} + +/** * device_link_check_waiting_consumers - Try to unmark waiting consumers * * Loops through all consumers waiting on suppliers and tries to add all their @@ -456,12 +469,19 @@ static void device_link_wait_for_supplier(struct device *consumer) static void device_link_check_waiting_consumers(void) { struct device *dev, *tmp; + int ret; mutex_lock(&wfs_lock); list_for_each_entry_safe(dev, tmp, &wait_for_suppliers, - links.needs_suppliers) - if (!dev->bus->add_links(dev)) + links.needs_suppliers) { + ret = 0; + if (dev->has_edit_links) + ret = driver_edit_links(dev); + else if (dev->bus->add_links) + ret = dev->bus->add_links(dev); + if (!ret) list_del_init(&dev->links.needs_suppliers); + } mutex_unlock(&wfs_lock); } diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 994a90747420..5e7041ede0d7 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -698,6 +698,12 @@ 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); + if (drv->edit_links) { + if (drv->edit_links(dev)) + dev->has_edit_links = true; + else + device_link_remove_from_wfs(dev); + } pm_runtime_get_suppliers(dev); if (dev->parent) pm_runtime_get_sync(dev->parent); @@ -786,6 +792,29 @@ struct device_attach_data { bool have_async; }; +static int __driver_edit_links(struct device_driver *drv, void *data) +{ + struct device *dev = data; + + if (!drv->edit_links) + return 0; + + if (driver_match_device(drv, dev) <= 0) + return 0; + + return drv->edit_links(dev); +} + +int driver_edit_links(struct device *dev) +{ + int ret; + + device_lock(dev); + ret = bus_for_each_drv(dev->bus, NULL, dev, __driver_edit_links); + device_unlock(dev); + return ret; +} + static int __device_attach_driver(struct device_driver *drv, void *_data) { struct device_attach_data *data = _data; diff --git a/include/linux/device.h b/include/linux/device.h index 1e05911325f0..d3991810f39d 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -349,6 +349,20 @@ enum probe_type { * @probe_type: Type of the probe (synchronous or asynchronous) to use. * @of_match_table: The open firmware table. * @acpi_match_table: The ACPI match table. + * @edit_links: Called to allow a matched driver to edit the device links the + * bus might have added incorrectly. This will be useful to handle + * cases where the bus incorrectly adds functional dependencies + * that aren't true or tries to create cyclic dependencies. But + * doesn't correctly handle functional dependencies that are + * missed by the bus as the supplier's sync_state might get to + * execute before the driver for a missing consumer is loaded and + * gets to edit the device links for the consumer. + * + * This function might be called multiple times after a new device + * is added. The function is expected to create all the device + * links for the new device and return 0 if it was completed + * successfully or return an error if it needs to be reattempted + * in the future. * @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. @@ -388,6 +402,7 @@ struct device_driver { const struct of_device_id *of_match_table; const struct acpi_device_id *acpi_match_table; + int (*edit_links)(struct device *dev); int (*probe) (struct device *dev); int (*remove) (struct device *dev); void (*shutdown) (struct device *dev); @@ -1220,6 +1235,8 @@ struct dev_links_info { * @offline: Set after successful invocation of bus type's .offline(). * @of_node_reused: Set if the device-tree node is shared with an ancestor * device. + * @has_edit_links: This device has a driver than is capable of + * editing the device links created by driver core. * @dma_coherent: this particular device is dma coherent, even if the * architecture supports non-coherent devices. * @@ -1313,6 +1330,7 @@ struct device { bool offline_disabled:1; bool offline:1; bool of_node_reused:1; + bool has_edit_links: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) @@ -1564,6 +1582,7 @@ extern int __must_check device_attach(struct device *dev); extern int __must_check driver_attach(struct device_driver *drv); extern void device_initial_probe(struct device *dev); extern int __must_check device_reprobe(struct device *dev); +extern int driver_edit_links(struct device *dev); extern bool device_is_bound(struct device *dev); @@ -1654,6 +1673,7 @@ struct device_link *device_link_add(struct device *consumer, struct device *supplier, u32 flags); 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); #ifndef dev_fmt #define dev_fmt(fmt) fmt |