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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/base/dd.c
2 * drivers/base/dd.c - The core device/driver interactions.
4 * This file contains the (sometimes tricky) code that controls the
5 * interactions between devices and drivers, which primarily includes
6 * driver binding and unbinding.
8 * All of this code used to exist in drivers/base/bus.c, but was
9 * relocated to here in the name of compartmentalization (since it wasn't
10 * strictly code just for the 'struct bus_type'.
12 * Copyright (c) 2002-5 Patrick Mochel
13 * Copyright (c) 2002-3 Open Source Development Labs
14 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
15 * Copyright (c) 2007 Novell Inc.
17 * This file is released under the GPLv2
20 #include <linux/device.h>
21 #include <linux/delay.h>
22 #include <linux/module.h>
23 #include <linux/kthread.h>
24 #include <linux/wait.h>
25 #include <linux/async.h>
28 #include "power/power.h"
31 static void driver_bound(struct device
*dev
)
33 if (klist_node_attached(&dev
->p
->knode_driver
)) {
34 printk(KERN_WARNING
"%s: device %s already bound\n",
35 __func__
, kobject_name(&dev
->kobj
));
39 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev
),
40 __func__
, dev
->driver
->name
);
43 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
44 BUS_NOTIFY_BOUND_DRIVER
, dev
);
46 klist_add_tail(&dev
->p
->knode_driver
, &dev
->driver
->p
->klist_devices
);
49 static int driver_sysfs_add(struct device
*dev
)
53 ret
= sysfs_create_link(&dev
->driver
->p
->kobj
, &dev
->kobj
,
54 kobject_name(&dev
->kobj
));
56 ret
= sysfs_create_link(&dev
->kobj
, &dev
->driver
->p
->kobj
,
59 sysfs_remove_link(&dev
->driver
->p
->kobj
,
60 kobject_name(&dev
->kobj
));
65 static void driver_sysfs_remove(struct device
*dev
)
67 struct device_driver
*drv
= dev
->driver
;
70 sysfs_remove_link(&drv
->p
->kobj
, kobject_name(&dev
->kobj
));
71 sysfs_remove_link(&dev
->kobj
, "driver");
76 * device_bind_driver - bind a driver to one device.
79 * Allow manual attachment of a driver to a device.
80 * Caller must have already set @dev->driver.
82 * Note that this does not modify the bus reference count
83 * nor take the bus's rwsem. Please verify those are accounted
84 * for before calling this. (It is ok to call with no other effort
85 * from a driver's probe() method.)
87 * This function must be called with @dev->sem held.
89 int device_bind_driver(struct device
*dev
)
93 ret
= driver_sysfs_add(dev
);
98 EXPORT_SYMBOL_GPL(device_bind_driver
);
100 static atomic_t probe_count
= ATOMIC_INIT(0);
101 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue
);
103 static int really_probe(struct device
*dev
, struct device_driver
*drv
)
107 atomic_inc(&probe_count
);
108 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
109 drv
->bus
->name
, __func__
, drv
->name
, dev_name(dev
));
110 WARN_ON(!list_empty(&dev
->devres_head
));
113 if (driver_sysfs_add(dev
)) {
114 printk(KERN_ERR
"%s: driver_sysfs_add(%s) failed\n",
115 __func__
, dev_name(dev
));
119 if (dev
->bus
->probe
) {
120 ret
= dev
->bus
->probe(dev
);
123 } else if (drv
->probe
) {
124 ret
= drv
->probe(dev
);
131 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
132 drv
->bus
->name
, __func__
, dev_name(dev
), drv
->name
);
136 devres_release_all(dev
);
137 driver_sysfs_remove(dev
);
140 if (ret
!= -ENODEV
&& ret
!= -ENXIO
) {
141 /* driver matched but the probe failed */
143 "%s: probe of %s failed with error %d\n",
144 drv
->name
, dev_name(dev
), ret
);
147 * Ignore errors returned by ->probe so that the next driver can try
152 atomic_dec(&probe_count
);
153 wake_up(&probe_waitqueue
);
159 * Determine if the probe sequence is finished or not.
161 * Should somehow figure out how to use a semaphore, not an atomic variable...
163 int driver_probe_done(void)
165 pr_debug("%s: probe_count = %d\n", __func__
,
166 atomic_read(&probe_count
));
167 if (atomic_read(&probe_count
))
173 * wait_for_device_probe
174 * Wait for device probing to be completed.
176 void wait_for_device_probe(void)
178 /* wait for the known devices to complete their probing */
179 wait_event(probe_waitqueue
, atomic_read(&probe_count
) == 0);
180 async_synchronize_full();
182 EXPORT_SYMBOL_GPL(wait_for_device_probe
);
185 * driver_probe_device - attempt to bind device & driver together
186 * @drv: driver to bind a device to
187 * @dev: device to try to bind to the driver
189 * This function returns -ENODEV if the device is not registered,
190 * 1 if the device is bound sucessfully and 0 otherwise.
192 * This function must be called with @dev->sem held. When called for a
193 * USB interface, @dev->parent->sem must be held as well.
195 int driver_probe_device(struct device_driver
*drv
, struct device
*dev
)
199 if (!device_is_registered(dev
))
202 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
203 drv
->bus
->name
, __func__
, dev_name(dev
), drv
->name
);
205 ret
= really_probe(dev
, drv
);
210 static int __device_attach(struct device_driver
*drv
, void *data
)
212 struct device
*dev
= data
;
214 if (!driver_match_device(drv
, dev
))
217 return driver_probe_device(drv
, dev
);
221 * device_attach - try to attach device to a driver.
224 * Walk the list of drivers that the bus has and call
225 * driver_probe_device() for each pair. If a compatible
226 * pair is found, break out and return.
228 * Returns 1 if the device was bound to a driver;
229 * 0 if no matching device was found;
230 * -ENODEV if the device is not registered.
232 * When called for a USB interface, @dev->parent->sem must be held.
234 int device_attach(struct device
*dev
)
240 ret
= device_bind_driver(dev
);
248 ret
= bus_for_each_drv(dev
->bus
, NULL
, dev
, __device_attach
);
253 EXPORT_SYMBOL_GPL(device_attach
);
255 static int __driver_attach(struct device
*dev
, void *data
)
257 struct device_driver
*drv
= data
;
260 * Lock device and try to bind to it. We drop the error
261 * here and always return 0, because we need to keep trying
262 * to bind to devices and some drivers will return an error
263 * simply if it didn't support the device.
265 * driver_probe_device() will spit a warning if there
269 if (!driver_match_device(drv
, dev
))
272 if (dev
->parent
) /* Needed for USB */
273 down(&dev
->parent
->sem
);
276 driver_probe_device(drv
, dev
);
279 up(&dev
->parent
->sem
);
285 * driver_attach - try to bind driver to devices.
288 * Walk the list of devices that the bus has on it and try to
289 * match the driver with each one. If driver_probe_device()
290 * returns 0 and the @dev->driver is set, we've found a
293 int driver_attach(struct device_driver
*drv
)
295 return bus_for_each_dev(drv
->bus
, NULL
, drv
, __driver_attach
);
297 EXPORT_SYMBOL_GPL(driver_attach
);
300 * __device_release_driver() must be called with @dev->sem held.
301 * When called for a USB interface, @dev->parent->sem must be held as well.
303 static void __device_release_driver(struct device
*dev
)
305 struct device_driver
*drv
;
309 driver_sysfs_remove(dev
);
312 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
313 BUS_NOTIFY_UNBIND_DRIVER
,
316 if (dev
->bus
&& dev
->bus
->remove
)
317 dev
->bus
->remove(dev
);
318 else if (drv
->remove
)
320 devres_release_all(dev
);
322 klist_remove(&dev
->p
->knode_driver
);
327 * device_release_driver - manually detach device from driver.
330 * Manually detach device from driver.
331 * When called for a USB interface, @dev->parent->sem must be held.
333 void device_release_driver(struct device
*dev
)
336 * If anyone calls device_release_driver() recursively from
337 * within their ->remove callback for the same device, they
338 * will deadlock right here.
341 __device_release_driver(dev
);
344 EXPORT_SYMBOL_GPL(device_release_driver
);
347 * driver_detach - detach driver from all devices it controls.
350 void driver_detach(struct device_driver
*drv
)
352 struct device_private
*dev_prv
;
356 spin_lock(&drv
->p
->klist_devices
.k_lock
);
357 if (list_empty(&drv
->p
->klist_devices
.k_list
)) {
358 spin_unlock(&drv
->p
->klist_devices
.k_lock
);
361 dev_prv
= list_entry(drv
->p
->klist_devices
.k_list
.prev
,
362 struct device_private
,
363 knode_driver
.n_node
);
364 dev
= dev_prv
->device
;
366 spin_unlock(&drv
->p
->klist_devices
.k_lock
);
368 if (dev
->parent
) /* Needed for USB */
369 down(&dev
->parent
->sem
);
371 if (dev
->driver
== drv
)
372 __device_release_driver(dev
);
375 up(&dev
->parent
->sem
);