Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / drivers / base / dd.c
1 /*
2  * drivers/base/dd.c - The core device/driver interactions.
3  *
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.
7  *
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'.
11  *
12  * Copyright (c) 2002-5 Patrick Mochel
13  * Copyright (c) 2002-3 Open Source Development Labs
14  * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
15  * Copyright (c) 2007-2009 Novell Inc.
16  *
17  * This file is released under the GPLv2
18  */
19
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>
26 #include <linux/pm_runtime.h>
27
28 #include "base.h"
29 #include "power/power.h"
30
31
32 static void driver_bound(struct device *dev)
33 {
34         if (klist_node_attached(&dev->p->knode_driver)) {
35                 printk(KERN_WARNING "%s: device %s already bound\n",
36                         __func__, kobject_name(&dev->kobj));
37                 return;
38         }
39
40         pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev),
41                  __func__, dev->driver->name);
42
43         klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
44
45         if (dev->bus)
46                 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
47                                              BUS_NOTIFY_BOUND_DRIVER, dev);
48 }
49
50 static int driver_sysfs_add(struct device *dev)
51 {
52         int ret;
53
54         if (dev->bus)
55                 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
56                                              BUS_NOTIFY_BIND_DRIVER, dev);
57
58         ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
59                           kobject_name(&dev->kobj));
60         if (ret == 0) {
61                 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
62                                         "driver");
63                 if (ret)
64                         sysfs_remove_link(&dev->driver->p->kobj,
65                                         kobject_name(&dev->kobj));
66         }
67         return ret;
68 }
69
70 static void driver_sysfs_remove(struct device *dev)
71 {
72         struct device_driver *drv = dev->driver;
73
74         if (drv) {
75                 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
76                 sysfs_remove_link(&dev->kobj, "driver");
77         }
78 }
79
80 /**
81  * device_bind_driver - bind a driver to one device.
82  * @dev: device.
83  *
84  * Allow manual attachment of a driver to a device.
85  * Caller must have already set @dev->driver.
86  *
87  * Note that this does not modify the bus reference count
88  * nor take the bus's rwsem. Please verify those are accounted
89  * for before calling this. (It is ok to call with no other effort
90  * from a driver's probe() method.)
91  *
92  * This function must be called with the device lock held.
93  */
94 int device_bind_driver(struct device *dev)
95 {
96         int ret;
97
98         ret = driver_sysfs_add(dev);
99         if (!ret)
100                 driver_bound(dev);
101         return ret;
102 }
103 EXPORT_SYMBOL_GPL(device_bind_driver);
104
105 static atomic_t probe_count = ATOMIC_INIT(0);
106 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
107
108 static int really_probe(struct device *dev, struct device_driver *drv)
109 {
110         int ret = 0;
111
112         atomic_inc(&probe_count);
113         pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
114                  drv->bus->name, __func__, drv->name, dev_name(dev));
115         WARN_ON(!list_empty(&dev->devres_head));
116
117         dev->driver = drv;
118         if (driver_sysfs_add(dev)) {
119                 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
120                         __func__, dev_name(dev));
121                 goto probe_failed;
122         }
123
124         if (dev->bus->probe) {
125                 ret = dev->bus->probe(dev);
126                 if (ret)
127                         goto probe_failed;
128         } else if (drv->probe) {
129                 ret = drv->probe(dev);
130                 if (ret)
131                         goto probe_failed;
132         }
133
134         driver_bound(dev);
135         ret = 1;
136         pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
137                  drv->bus->name, __func__, dev_name(dev), drv->name);
138         goto done;
139
140 probe_failed:
141         devres_release_all(dev);
142         driver_sysfs_remove(dev);
143         dev->driver = NULL;
144
145         if (ret != -ENODEV && ret != -ENXIO) {
146                 /* driver matched but the probe failed */
147                 printk(KERN_WARNING
148                        "%s: probe of %s failed with error %d\n",
149                        drv->name, dev_name(dev), ret);
150         }
151         /*
152          * Ignore errors returned by ->probe so that the next driver can try
153          * its luck.
154          */
155         ret = 0;
156 done:
157         atomic_dec(&probe_count);
158         wake_up(&probe_waitqueue);
159         return ret;
160 }
161
162 /**
163  * driver_probe_done
164  * Determine if the probe sequence is finished or not.
165  *
166  * Should somehow figure out how to use a semaphore, not an atomic variable...
167  */
168 int driver_probe_done(void)
169 {
170         pr_debug("%s: probe_count = %d\n", __func__,
171                  atomic_read(&probe_count));
172         if (atomic_read(&probe_count))
173                 return -EBUSY;
174         return 0;
175 }
176
177 /**
178  * wait_for_device_probe
179  * Wait for device probing to be completed.
180  */
181 void wait_for_device_probe(void)
182 {
183         /* wait for the known devices to complete their probing */
184         wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
185         async_synchronize_full();
186 }
187 EXPORT_SYMBOL_GPL(wait_for_device_probe);
188
189 /**
190  * driver_probe_device - attempt to bind device & driver together
191  * @drv: driver to bind a device to
192  * @dev: device to try to bind to the driver
193  *
194  * This function returns -ENODEV if the device is not registered,
195  * 1 if the device is bound successfully and 0 otherwise.
196  *
197  * This function must be called with @dev lock held.  When called for a
198  * USB interface, @dev->parent lock must be held as well.
199  */
200 int driver_probe_device(struct device_driver *drv, struct device *dev)
201 {
202         int ret = 0;
203
204         if (!device_is_registered(dev))
205                 return -ENODEV;
206
207         pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
208                  drv->bus->name, __func__, dev_name(dev), drv->name);
209
210         pm_runtime_get_noresume(dev);
211         pm_runtime_barrier(dev);
212         ret = really_probe(dev, drv);
213         pm_runtime_put_sync(dev);
214
215         return ret;
216 }
217
218 static int __device_attach(struct device_driver *drv, void *data)
219 {
220         struct device *dev = data;
221
222         if (!driver_match_device(drv, dev))
223                 return 0;
224
225         return driver_probe_device(drv, dev);
226 }
227
228 /**
229  * device_attach - try to attach device to a driver.
230  * @dev: device.
231  *
232  * Walk the list of drivers that the bus has and call
233  * driver_probe_device() for each pair. If a compatible
234  * pair is found, break out and return.
235  *
236  * Returns 1 if the device was bound to a driver;
237  * 0 if no matching driver was found;
238  * -ENODEV if the device is not registered.
239  *
240  * When called for a USB interface, @dev->parent lock must be held.
241  */
242 int device_attach(struct device *dev)
243 {
244         int ret = 0;
245
246         device_lock(dev);
247         if (dev->driver) {
248                 if (klist_node_attached(&dev->p->knode_driver)) {
249                         ret = 1;
250                         goto out_unlock;
251                 }
252                 ret = device_bind_driver(dev);
253                 if (ret == 0)
254                         ret = 1;
255                 else {
256                         dev->driver = NULL;
257                         ret = 0;
258                 }
259         } else {
260                 pm_runtime_get_noresume(dev);
261                 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
262                 pm_runtime_put_sync(dev);
263         }
264 out_unlock:
265         device_unlock(dev);
266         return ret;
267 }
268 EXPORT_SYMBOL_GPL(device_attach);
269
270 static int __driver_attach(struct device *dev, void *data)
271 {
272         struct device_driver *drv = data;
273
274         /*
275          * Lock device and try to bind to it. We drop the error
276          * here and always return 0, because we need to keep trying
277          * to bind to devices and some drivers will return an error
278          * simply if it didn't support the device.
279          *
280          * driver_probe_device() will spit a warning if there
281          * is an error.
282          */
283
284         if (!driver_match_device(drv, dev))
285                 return 0;
286
287         if (dev->parent)        /* Needed for USB */
288                 device_lock(dev->parent);
289         device_lock(dev);
290         if (!dev->driver)
291                 driver_probe_device(drv, dev);
292         device_unlock(dev);
293         if (dev->parent)
294                 device_unlock(dev->parent);
295
296         return 0;
297 }
298
299 /**
300  * driver_attach - try to bind driver to devices.
301  * @drv: driver.
302  *
303  * Walk the list of devices that the bus has on it and try to
304  * match the driver with each one.  If driver_probe_device()
305  * returns 0 and the @dev->driver is set, we've found a
306  * compatible pair.
307  */
308 int driver_attach(struct device_driver *drv)
309 {
310         return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
311 }
312 EXPORT_SYMBOL_GPL(driver_attach);
313
314 /*
315  * __device_release_driver() must be called with @dev lock held.
316  * When called for a USB interface, @dev->parent lock must be held as well.
317  */
318 static void __device_release_driver(struct device *dev)
319 {
320         struct device_driver *drv;
321
322         drv = dev->driver;
323         if (drv) {
324                 pm_runtime_get_sync(dev);
325
326                 driver_sysfs_remove(dev);
327
328                 if (dev->bus)
329                         blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
330                                                      BUS_NOTIFY_UNBIND_DRIVER,
331                                                      dev);
332
333                 pm_runtime_put_sync(dev);
334
335                 if (dev->bus && dev->bus->remove)
336                         dev->bus->remove(dev);
337                 else if (drv->remove)
338                         drv->remove(dev);
339                 devres_release_all(dev);
340                 dev->driver = NULL;
341                 klist_remove(&dev->p->knode_driver);
342                 if (dev->bus)
343                         blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
344                                                      BUS_NOTIFY_UNBOUND_DRIVER,
345                                                      dev);
346
347         }
348 }
349
350 /**
351  * device_release_driver - manually detach device from driver.
352  * @dev: device.
353  *
354  * Manually detach device from driver.
355  * When called for a USB interface, @dev->parent lock must be held.
356  */
357 void device_release_driver(struct device *dev)
358 {
359         /*
360          * If anyone calls device_release_driver() recursively from
361          * within their ->remove callback for the same device, they
362          * will deadlock right here.
363          */
364         device_lock(dev);
365         __device_release_driver(dev);
366         device_unlock(dev);
367 }
368 EXPORT_SYMBOL_GPL(device_release_driver);
369
370 /**
371  * driver_detach - detach driver from all devices it controls.
372  * @drv: driver.
373  */
374 void driver_detach(struct device_driver *drv)
375 {
376         struct device_private *dev_prv;
377         struct device *dev;
378
379         for (;;) {
380                 spin_lock(&drv->p->klist_devices.k_lock);
381                 if (list_empty(&drv->p->klist_devices.k_list)) {
382                         spin_unlock(&drv->p->klist_devices.k_lock);
383                         break;
384                 }
385                 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
386                                      struct device_private,
387                                      knode_driver.n_node);
388                 dev = dev_prv->device;
389                 get_device(dev);
390                 spin_unlock(&drv->p->klist_devices.k_lock);
391
392                 if (dev->parent)        /* Needed for USB */
393                         device_lock(dev->parent);
394                 device_lock(dev);
395                 if (dev->driver == drv)
396                         __device_release_driver(dev);
397                 device_unlock(dev);
398                 if (dev->parent)
399                         device_unlock(dev->parent);
400                 put_device(dev);
401         }
402 }
403
404 /*
405  * These exports can't be _GPL due to .h files using this within them, and it
406  * might break something that was previously working...
407  */
408 void *dev_get_drvdata(const struct device *dev)
409 {
410         if (dev && dev->p)
411                 return dev->p->driver_data;
412         return NULL;
413 }
414 EXPORT_SYMBOL(dev_get_drvdata);
415
416 int dev_set_drvdata(struct device *dev, void *data)
417 {
418         int error;
419
420         if (!dev->p) {
421                 error = device_private_init(dev);
422                 if (error)
423                         return error;
424         }
425         dev->p->driver_data = data;
426         return 0;
427 }
428 EXPORT_SYMBOL(dev_set_drvdata);