| /* |
| * drivers/base/dd.c - The core device/driver interactions. |
| * |
| * This file contains the (sometimes tricky) code that controls the |
| * interactions between devices and drivers, which primarily includes |
| * driver binding and unbinding. |
| * |
| * All of this code used to exist in drivers/base/bus.c, but was |
| * relocated to here in the name of compartmentalization (since it wasn't |
| * strictly code just for the 'struct bus_type'. |
| * |
| * Copyright (c) 2002-5 Patrick Mochel |
| * Copyright (c) 2002-3 Open Source Development Labs |
| * |
| * This file is released under the GPLv2 |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/module.h> |
| |
| #include "base.h" |
| #include "power/power.h" |
| |
| #define to_drv(node) container_of(node, struct device_driver, kobj.entry) |
| |
| |
| /** |
| * device_bind_driver - bind a driver to one device. |
| * @dev: device. |
| * |
| * Allow manual attachment of a driver to a device. |
| * Caller must have already set @dev->driver. |
| * |
| * Note that this does not modify the bus reference count |
| * nor take the bus's rwsem. Please verify those are accounted |
| * for before calling this. (It is ok to call with no other effort |
| * from a driver's probe() method.) |
| * |
| * This function must be called with @dev->sem held. |
| */ |
| void device_bind_driver(struct device * dev) |
| { |
| if (klist_node_attached(&dev->knode_driver)) |
| return; |
| |
| pr_debug("bound device '%s' to driver '%s'\n", |
| dev->bus_id, dev->driver->name); |
| klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); |
| sysfs_create_link(&dev->driver->kobj, &dev->kobj, |
| kobject_name(&dev->kobj)); |
| sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver"); |
| } |
| |
| /** |
| * driver_probe_device - attempt to bind device & driver. |
| * @drv: driver. |
| * @dev: device. |
| * |
| * First, we call the bus's match function, if one present, which |
| * should compare the device IDs the driver supports with the |
| * device IDs of the device. Note we don't do this ourselves |
| * because we don't know the format of the ID structures, nor what |
| * is to be considered a match and what is not. |
| * |
| * This function returns 1 if a match is found, an error if one |
| * occurs (that is not -ENODEV or -ENXIO), and 0 otherwise. |
| * |
| * This function must be called with @dev->sem held. |
| */ |
| int driver_probe_device(struct device_driver * drv, struct device * dev) |
| { |
| int ret = 0; |
| |
| if (drv->bus->match && !drv->bus->match(dev, drv)) |
| goto Done; |
| |
| pr_debug("%s: Matched Device %s with Driver %s\n", |
| drv->bus->name, dev->bus_id, drv->name); |
| dev->driver = drv; |
| if (drv->probe) { |
| ret = drv->probe(dev); |
| if (ret) { |
| dev->driver = NULL; |
| goto ProbeFailed; |
| } |
| } |
| device_bind_driver(dev); |
| ret = 1; |
| pr_debug("%s: Bound Device %s to Driver %s\n", |
| drv->bus->name, dev->bus_id, drv->name); |
| goto Done; |
| |
| ProbeFailed: |
| if (ret == -ENODEV || ret == -ENXIO) { |
| /* Driver matched, but didn't support device |
| * or device not found. |
| * Not an error; keep going. |
| */ |
| ret = 0; |
| } else { |
| /* driver matched but the probe failed */ |
| printk(KERN_WARNING |
| "%s: probe of %s failed with error %d\n", |
| drv->name, dev->bus_id, ret); |
| } |
| Done: |
| return ret; |
| } |
| |
| static int __device_attach(struct device_driver * drv, void * data) |
| { |
| struct device * dev = data; |
| return driver_probe_device(drv, dev); |
| } |
| |
| /** |
| * device_attach - try to attach device to a driver. |
| * @dev: device. |
| * |
| * Walk the list of drivers that the bus has and call |
| * driver_probe_device() for each pair. If a compatible |
| * pair is found, break out and return. |
| * |
| * Returns 1 if the device was bound to a driver; |
| * 0 if no matching device was found; error code otherwise. |
| */ |
| int device_attach(struct device * dev) |
| { |
| int ret = 0; |
| |
| down(&dev->sem); |
| if (dev->driver) { |
| device_bind_driver(dev); |
| ret = 1; |
| } else |
| ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); |
| up(&dev->sem); |
| return ret; |
| } |
| |
| static int __driver_attach(struct device * dev, void * data) |
| { |
| struct device_driver * drv = data; |
| |
| /* |
| * Lock device and try to bind to it. We drop the error |
| * here and always return 0, because we need to keep trying |
| * to bind to devices and some drivers will return an error |
| * simply if it didn't support the device. |
| * |
| * driver_probe_device() will spit a warning if there |
| * is an error. |
| */ |
| |
| down(&dev->sem); |
| if (!dev->driver) |
| driver_probe_device(drv, dev); |
| up(&dev->sem); |
| |
| return 0; |
| } |
| |
| /** |
| * driver_attach - try to bind driver to devices. |
| * @drv: driver. |
| * |
| * Walk the list of devices that the bus has on it and try to |
| * match the driver with each one. If driver_probe_device() |
| * returns 0 and the @dev->driver is set, we've found a |
| * compatible pair. |
| */ |
| void driver_attach(struct device_driver * drv) |
| { |
| bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
| } |
| |
| /** |
| * device_release_driver - manually detach device from driver. |
| * @dev: device. |
| * |
| * Manually detach device from driver. |
| * |
| * __device_release_driver() must be called with @dev->sem held. |
| */ |
| |
| static void __device_release_driver(struct device * dev) |
| { |
| struct device_driver * drv; |
| |
| drv = dev->driver; |
| if (drv) { |
| get_driver(drv); |
| sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); |
| sysfs_remove_link(&dev->kobj, "driver"); |
| klist_remove(&dev->knode_driver); |
| |
| if (drv->remove) |
| drv->remove(dev); |
| dev->driver = NULL; |
| put_driver(drv); |
| } |
| } |
| |
| void device_release_driver(struct device * dev) |
| { |
| /* |
| * If anyone calls device_release_driver() recursively from |
| * within their ->remove callback for the same device, they |
| * will deadlock right here. |
| */ |
| down(&dev->sem); |
| __device_release_driver(dev); |
| up(&dev->sem); |
| } |
| |
| |
| /** |
| * driver_detach - detach driver from all devices it controls. |
| * @drv: driver. |
| */ |
| void driver_detach(struct device_driver * drv) |
| { |
| struct device * dev; |
| |
| for (;;) { |
| spin_lock(&drv->klist_devices.k_lock); |
| if (list_empty(&drv->klist_devices.k_list)) { |
| spin_unlock(&drv->klist_devices.k_lock); |
| break; |
| } |
| dev = list_entry(drv->klist_devices.k_list.prev, |
| struct device, knode_driver.n_node); |
| get_device(dev); |
| spin_unlock(&drv->klist_devices.k_lock); |
| |
| down(&dev->sem); |
| if (dev->driver == drv) |
| __device_release_driver(dev); |
| up(&dev->sem); |
| put_device(dev); |
| } |
| } |
| |
| |
| EXPORT_SYMBOL_GPL(device_bind_driver); |
| EXPORT_SYMBOL_GPL(device_release_driver); |
| EXPORT_SYMBOL_GPL(device_attach); |
| EXPORT_SYMBOL_GPL(driver_attach); |
| |