diff options
Diffstat (limited to 'drivers/base/auxiliary.c')
| -rw-r--r-- | drivers/base/auxiliary.c | 160 |
1 files changed, 125 insertions, 35 deletions
diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c index d3a2c40c2f12..dba7c8e13a53 100644 --- a/drivers/base/auxiliary.c +++ b/drivers/base/auxiliary.c @@ -92,7 +92,7 @@ * Auxiliary devices are created and registered by a subsystem-level core * device that needs to break up its functionality into smaller fragments. One * way to extend the scope of an auxiliary_device is to encapsulate it within a - * domain- pecific structure defined by the parent device. This structure + * domain-specific structure defined by the parent device. This structure * contains the auxiliary_device and any associated shared data/callbacks * needed to establish the connection with the parent. * @@ -156,6 +156,16 @@ * }, * .ops = my_custom_ops, * }; + * + * Please note that such custom ops approach is valid, but it is hard to implement + * it right without global locks per-device to protect from auxiliary_drv removal + * during call to that ops. In addition, this implementation lacks proper module + * dependency, which causes to load/unload races between auxiliary parent and devices + * modules. + * + * The most easiest way to provide these ops reliably without needing to + * have a lock is to EXPORT_SYMBOL*() them and rely on already existing + * modules infrastructure for validity and correct dependencies chains. */ static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id, @@ -177,10 +187,10 @@ static const struct auxiliary_device_id *auxiliary_match_id(const struct auxilia return NULL; } -static int auxiliary_match(struct device *dev, struct device_driver *drv) +static int auxiliary_match(struct device *dev, const struct device_driver *drv) { struct auxiliary_device *auxdev = to_auxiliary_dev(dev); - struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv); + const struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv); return !!auxiliary_match_id(auxdrv->id_table, auxdev); } @@ -203,7 +213,7 @@ static const struct dev_pm_ops auxiliary_dev_pm_ops = { static int auxiliary_bus_probe(struct device *dev) { - struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); + const struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); struct auxiliary_device *auxdev = to_auxiliary_dev(dev); int ret; @@ -222,7 +232,7 @@ static int auxiliary_bus_probe(struct device *dev) static void auxiliary_bus_remove(struct device *dev) { - struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); + const struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); struct auxiliary_device *auxdev = to_auxiliary_dev(dev); if (auxdrv->remove) @@ -232,7 +242,7 @@ static void auxiliary_bus_remove(struct device *dev) static void auxiliary_bus_shutdown(struct device *dev) { - struct auxiliary_driver *auxdrv = NULL; + const struct auxiliary_driver *auxdrv = NULL; struct auxiliary_device *auxdev; if (dev->driver) { @@ -287,6 +297,7 @@ int auxiliary_device_init(struct auxiliary_device *auxdev) dev->bus = &auxiliary_bus_type; device_initialize(&auxdev->dev); + mutex_init(&auxdev->sysfs.lock); return 0; } EXPORT_SYMBOL_GPL(auxiliary_device_init); @@ -335,35 +346,6 @@ int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname) EXPORT_SYMBOL_GPL(__auxiliary_device_add); /** - * auxiliary_find_device - auxiliary device iterator for locating a particular device. - * @start: Device to begin with - * @data: Data to pass to match function - * @match: Callback function to check device - * - * This function returns a reference to a device that is 'found' - * for later use, as determined by the @match callback. - * - * The reference returned should be released with put_device(). - * - * The callback should return 0 if the device doesn't match and non-zero - * if it does. If the callback returns non-zero, this function will - * return to the caller and not iterate over any more devices. - */ -struct auxiliary_device *auxiliary_find_device(struct device *start, - const void *data, - int (*match)(struct device *dev, const void *data)) -{ - struct device *dev; - - dev = bus_find_device(&auxiliary_bus_type, start, data, match); - if (!dev) - return NULL; - - return to_auxiliary_dev(dev); -} -EXPORT_SYMBOL_GPL(auxiliary_find_device); - -/** * __auxiliary_driver_register - register a driver for auxiliary bus devices * @auxdrv: auxiliary_driver structure * @owner: owning module/driver @@ -413,6 +395,114 @@ void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv) } EXPORT_SYMBOL_GPL(auxiliary_driver_unregister); +static void auxiliary_device_release(struct device *dev) +{ + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); + + kfree(auxdev); +} + +/** + * auxiliary_device_create - create a device on the auxiliary bus + * @dev: parent device + * @modname: module name used to create the auxiliary driver name. + * @devname: auxiliary bus device name + * @platform_data: auxiliary bus device platform data + * @id: auxiliary bus device id + * + * Helper to create an auxiliary bus device. + * The device created matches driver 'modname.devname' on the auxiliary bus. + */ +struct auxiliary_device *auxiliary_device_create(struct device *dev, + const char *modname, + const char *devname, + void *platform_data, + int id) +{ + struct auxiliary_device *auxdev; + int ret; + + auxdev = kzalloc(sizeof(*auxdev), GFP_KERNEL); + if (!auxdev) + return NULL; + + auxdev->id = id; + auxdev->name = devname; + auxdev->dev.parent = dev; + auxdev->dev.platform_data = platform_data; + auxdev->dev.release = auxiliary_device_release; + device_set_of_node_from_dev(&auxdev->dev, dev); + + ret = auxiliary_device_init(auxdev); + if (ret) { + kfree(auxdev); + return NULL; + } + + ret = __auxiliary_device_add(auxdev, modname); + if (ret) { + /* + * It may look odd but auxdev should not be freed here. + * auxiliary_device_uninit() calls device_put() which call + * the device release function, freeing auxdev. + */ + auxiliary_device_uninit(auxdev); + return NULL; + } + + return auxdev; +} +EXPORT_SYMBOL_GPL(auxiliary_device_create); + +/** + * auxiliary_device_destroy - remove an auxiliary device + * @auxdev: pointer to the auxdev to be removed + * + * Helper to remove an auxiliary device created with + * auxiliary_device_create() + */ +void auxiliary_device_destroy(void *auxdev) +{ + struct auxiliary_device *_auxdev = auxdev; + + auxiliary_device_delete(_auxdev); + auxiliary_device_uninit(_auxdev); +} +EXPORT_SYMBOL_GPL(auxiliary_device_destroy); + +/** + * __devm_auxiliary_device_create - create a managed device on the auxiliary bus + * @dev: parent device + * @modname: module name used to create the auxiliary driver name. + * @devname: auxiliary bus device name + * @platform_data: auxiliary bus device platform data + * @id: auxiliary bus device id + * + * Device managed helper to create an auxiliary bus device. + * The device created matches driver 'modname.devname' on the auxiliary bus. + */ +struct auxiliary_device *__devm_auxiliary_device_create(struct device *dev, + const char *modname, + const char *devname, + void *platform_data, + int id) +{ + struct auxiliary_device *auxdev; + int ret; + + auxdev = auxiliary_device_create(dev, modname, devname, platform_data, id); + if (!auxdev) + return NULL; + + ret = devm_add_action_or_reset(dev, auxiliary_device_destroy, + auxdev); + if (ret) + return NULL; + + return auxdev; +} +EXPORT_SYMBOL_GPL(__devm_auxiliary_device_create); + void __init auxiliary_bus_init(void) { WARN_ON(bus_register(&auxiliary_bus_type)); |