| /* |
| * 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 |
| * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> |
| * Copyright (c) 2007 Novell Inc. |
| * |
| * This file is released under the GPLv2 |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/module.h> |
| #include <linux/kthread.h> |
| #include <linux/wait.h> |
| |
| #include "base.h" |
| #include "power/power.h" |
| |
| |
| static void driver_bound(struct device *dev) |
| { |
| if (klist_node_attached(&dev->knode_driver)) { |
| printk(KERN_WARNING "%s: device %s already bound\n", |
| __func__, kobject_name(&dev->kobj)); |
| return; |
| } |
| |
| pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev), |
| __func__, dev->driver->name); |
| |
| if (dev->bus) |
| blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
| BUS_NOTIFY_BOUND_DRIVER, dev); |
| |
| klist_add_tail(&dev->knode_driver, &dev->driver->p->klist_devices); |
| } |
| |
| static int driver_sysfs_add(struct device *dev) |
| { |
| int ret; |
| |
| ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, |
| kobject_name(&dev->kobj)); |
| if (ret == 0) { |
| ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, |
| "driver"); |
| if (ret) |
| sysfs_remove_link(&dev->driver->p->kobj, |
| kobject_name(&dev->kobj)); |
| } |
| return ret; |
| } |
| |
| static void driver_sysfs_remove(struct device *dev) |
| { |
| struct device_driver *drv = dev->driver; |
| |
| if (drv) { |
| sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); |
| sysfs_remove_link(&dev->kobj, "driver"); |
| } |
| } |
| |
| /** |
| * 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. |
| */ |
| int device_bind_driver(struct device *dev) |
| { |
| int ret; |
| |
| ret = driver_sysfs_add(dev); |
| if (!ret) |
| driver_bound(dev); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(device_bind_driver); |
| |
| static atomic_t probe_count = ATOMIC_INIT(0); |
| static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
| |
| static int really_probe(struct device *dev, struct device_driver *drv) |
| { |
| int ret = 0; |
| |
| atomic_inc(&probe_count); |
| pr_debug("bus: '%s': %s: probing driver %s with device %s\n", |
| drv->bus->name, __func__, drv->name, dev_name(dev)); |
| WARN_ON(!list_empty(&dev->devres_head)); |
| |
| dev->driver = drv; |
| if (driver_sysfs_add(dev)) { |
| printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", |
| __func__, dev_name(dev)); |
| goto probe_failed; |
| } |
| |
| if (dev->bus->probe) { |
| ret = dev->bus->probe(dev); |
| if (ret) |
| goto probe_failed; |
| } else if (drv->probe) { |
| ret = drv->probe(dev); |
| if (ret) |
| goto probe_failed; |
| } |
| |
| driver_bound(dev); |
| ret = 1; |
| pr_debug("bus: '%s': %s: bound device %s to driver %s\n", |
| drv->bus->name, __func__, dev_name(dev), drv->name); |
| goto done; |
| |
| probe_failed: |
| devres_release_all(dev); |
| driver_sysfs_remove(dev); |
| dev->driver = NULL; |
| |
| if (ret != -ENODEV && ret != -ENXIO) { |
| /* driver matched but the probe failed */ |
| printk(KERN_WARNING |
| "%s: probe of %s failed with error %d\n", |
| drv->name, dev_name(dev), ret); |
| } |
| /* |
| * Ignore errors returned by ->probe so that the next driver can try |
| * its luck. |
| */ |
| ret = 0; |
| done: |
| atomic_dec(&probe_count); |
| wake_up(&probe_waitqueue); |
| return ret; |
| } |
| |
| /** |
| * driver_probe_done |
| * Determine if the probe sequence is finished or not. |
| * |
| * Should somehow figure out how to use a semaphore, not an atomic variable... |
| */ |
| int driver_probe_done(void) |
| { |
| pr_debug("%s: probe_count = %d\n", __func__, |
| atomic_read(&probe_count)); |
| if (atomic_read(&probe_count)) |
| return -EBUSY; |
| return 0; |
| } |
| |
| /** |
| * driver_probe_device - attempt to bind device & driver together |
| * @drv: driver to bind a device to |
| * @dev: device to try to bind to the driver |
| * |
| * 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, -ENODEV if the device is |
| * not registered, and 0 otherwise. |
| * |
| * This function must be called with @dev->sem held. When called for a |
| * USB interface, @dev->parent->sem must be held as well. |
| */ |
| int driver_probe_device(struct device_driver *drv, struct device *dev) |
| { |
| int ret = 0; |
| |
| if (!device_is_registered(dev)) |
| return -ENODEV; |
| if (drv->bus->match && !drv->bus->match(dev, drv)) |
| goto done; |
| |
| pr_debug("bus: '%s': %s: matched device %s with driver %s\n", |
| drv->bus->name, __func__, dev_name(dev), drv->name); |
| |
| ret = really_probe(dev, drv); |
| |
| 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; |
| * -ENODEV if the device is not registered. |
| * |
| * When called for a USB interface, @dev->parent->sem must be held. |
| */ |
| int device_attach(struct device *dev) |
| { |
| int ret = 0; |
| |
| down(&dev->sem); |
| if (dev->driver) { |
| ret = device_bind_driver(dev); |
| if (ret == 0) |
| ret = 1; |
| else { |
| dev->driver = NULL; |
| ret = 0; |
| } |
| } else { |
| ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); |
| } |
| up(&dev->sem); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(device_attach); |
| |
| 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. |
| */ |
| |
| if (drv->bus->match && !drv->bus->match(dev, drv)) |
| return 0; |
| |
| if (dev->parent) /* Needed for USB */ |
| down(&dev->parent->sem); |
| down(&dev->sem); |
| if (!dev->driver) |
| driver_probe_device(drv, dev); |
| up(&dev->sem); |
| if (dev->parent) |
| up(&dev->parent->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. |
| */ |
| int driver_attach(struct device_driver *drv) |
| { |
| return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
| } |
| EXPORT_SYMBOL_GPL(driver_attach); |
| |
| /* |
| * __device_release_driver() must be called with @dev->sem held. |
| * When called for a USB interface, @dev->parent->sem must be held as well. |
| */ |
| static void __device_release_driver(struct device *dev) |
| { |
| struct device_driver *drv; |
| |
| drv = dev->driver; |
| if (drv) { |
| driver_sysfs_remove(dev); |
| sysfs_remove_link(&dev->kobj, "driver"); |
| |
| if (dev->bus) |
| blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
| BUS_NOTIFY_UNBIND_DRIVER, |
| dev); |
| |
| if (dev->bus && dev->bus->remove) |
| dev->bus->remove(dev); |
| else if (drv->remove) |
| drv->remove(dev); |
| devres_release_all(dev); |
| dev->driver = NULL; |
| klist_remove(&dev->knode_driver); |
| } |
| } |
| |
| /** |
| * device_release_driver - manually detach device from driver. |
| * @dev: device. |
| * |
| * Manually detach device from driver. |
| * When called for a USB interface, @dev->parent->sem must be held. |
| */ |
| 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); |
| } |
| EXPORT_SYMBOL_GPL(device_release_driver); |
| |
| /** |
| * 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->p->klist_devices.k_lock); |
| if (list_empty(&drv->p->klist_devices.k_list)) { |
| spin_unlock(&drv->p->klist_devices.k_lock); |
| break; |
| } |
| dev = list_entry(drv->p->klist_devices.k_list.prev, |
| struct device, knode_driver.n_node); |
| get_device(dev); |
| spin_unlock(&drv->p->klist_devices.k_lock); |
| |
| if (dev->parent) /* Needed for USB */ |
| down(&dev->parent->sem); |
| down(&dev->sem); |
| if (dev->driver == drv) |
| __device_release_driver(dev); |
| up(&dev->sem); |
| if (dev->parent) |
| up(&dev->parent->sem); |
| put_device(dev); |
| } |
| } |