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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
32static 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
50static 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
70static 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 */
94int 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}
103EXPORT_SYMBOL_GPL(device_bind_driver);
104
105static atomic_t probe_count = ATOMIC_INIT(0);
106static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
107
108static 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
140probe_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;
156done:
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 */
168int 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 */
181void 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}
187EXPORT_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 */
200int 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
218static 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 */
242int 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 }
264out_unlock:
265 device_unlock(dev);
266 return ret;
267}
268EXPORT_SYMBOL_GPL(device_attach);
269
270static 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 */
308int driver_attach(struct device_driver *drv)
309{
310 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
311}
312EXPORT_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 */
318static 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 */
357void 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}
368EXPORT_SYMBOL_GPL(device_release_driver);
369
370/**
371 * driver_detach - detach driver from all devices it controls.
372 * @drv: driver.
373 */
374void 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 */
408void *dev_get_drvdata(const struct device *dev)
409{
410 if (dev && dev->p)
411 return dev->p->driver_data;
412 return NULL;
413}
414EXPORT_SYMBOL(dev_get_drvdata);
415
416int 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}
428EXPORT_SYMBOL(dev_set_drvdata);
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#include <scsi/scsi_scan.h>
28
29#include "base.h"
30#include "power/power.h"
31
32/*
33 * Deferred Probe infrastructure.
34 *
35 * Sometimes driver probe order matters, but the kernel doesn't always have
36 * dependency information which means some drivers will get probed before a
37 * resource it depends on is available. For example, an SDHCI driver may
38 * first need a GPIO line from an i2c GPIO controller before it can be
39 * initialized. If a required resource is not available yet, a driver can
40 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
41 *
42 * Deferred probe maintains two lists of devices, a pending list and an active
43 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
44 * pending list. A successful driver probe will trigger moving all devices
45 * from the pending to the active list so that the workqueue will eventually
46 * retry them.
47 *
48 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
49 * of the (struct device*)->p->deferred_probe pointers are manipulated
50 */
51static DEFINE_MUTEX(deferred_probe_mutex);
52static LIST_HEAD(deferred_probe_pending_list);
53static LIST_HEAD(deferred_probe_active_list);
54static struct workqueue_struct *deferred_wq;
55
56/**
57 * deferred_probe_work_func() - Retry probing devices in the active list.
58 */
59static void deferred_probe_work_func(struct work_struct *work)
60{
61 struct device *dev;
62 struct device_private *private;
63 /*
64 * This block processes every device in the deferred 'active' list.
65 * Each device is removed from the active list and passed to
66 * bus_probe_device() to re-attempt the probe. The loop continues
67 * until every device in the active list is removed and retried.
68 *
69 * Note: Once the device is removed from the list and the mutex is
70 * released, it is possible for the device get freed by another thread
71 * and cause a illegal pointer dereference. This code uses
72 * get/put_device() to ensure the device structure cannot disappear
73 * from under our feet.
74 */
75 mutex_lock(&deferred_probe_mutex);
76 while (!list_empty(&deferred_probe_active_list)) {
77 private = list_first_entry(&deferred_probe_active_list,
78 typeof(*dev->p), deferred_probe);
79 dev = private->device;
80 list_del_init(&private->deferred_probe);
81
82 get_device(dev);
83
84 /*
85 * Drop the mutex while probing each device; the probe path may
86 * manipulate the deferred list
87 */
88 mutex_unlock(&deferred_probe_mutex);
89 dev_dbg(dev, "Retrying from deferred list\n");
90 bus_probe_device(dev);
91 mutex_lock(&deferred_probe_mutex);
92
93 put_device(dev);
94 }
95 mutex_unlock(&deferred_probe_mutex);
96}
97static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
98
99static void driver_deferred_probe_add(struct device *dev)
100{
101 mutex_lock(&deferred_probe_mutex);
102 if (list_empty(&dev->p->deferred_probe)) {
103 dev_dbg(dev, "Added to deferred list\n");
104 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
105 }
106 mutex_unlock(&deferred_probe_mutex);
107}
108
109void driver_deferred_probe_del(struct device *dev)
110{
111 mutex_lock(&deferred_probe_mutex);
112 if (!list_empty(&dev->p->deferred_probe)) {
113 dev_dbg(dev, "Removed from deferred list\n");
114 list_del_init(&dev->p->deferred_probe);
115 }
116 mutex_unlock(&deferred_probe_mutex);
117}
118
119static bool driver_deferred_probe_enable = false;
120/**
121 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
122 *
123 * This functions moves all devices from the pending list to the active
124 * list and schedules the deferred probe workqueue to process them. It
125 * should be called anytime a driver is successfully bound to a device.
126 */
127static void driver_deferred_probe_trigger(void)
128{
129 if (!driver_deferred_probe_enable)
130 return;
131
132 /*
133 * A successful probe means that all the devices in the pending list
134 * should be triggered to be reprobed. Move all the deferred devices
135 * into the active list so they can be retried by the workqueue
136 */
137 mutex_lock(&deferred_probe_mutex);
138 list_splice_tail_init(&deferred_probe_pending_list,
139 &deferred_probe_active_list);
140 mutex_unlock(&deferred_probe_mutex);
141
142 /*
143 * Kick the re-probe thread. It may already be scheduled, but it is
144 * safe to kick it again.
145 */
146 queue_work(deferred_wq, &deferred_probe_work);
147}
148
149/**
150 * deferred_probe_initcall() - Enable probing of deferred devices
151 *
152 * We don't want to get in the way when the bulk of drivers are getting probed.
153 * Instead, this initcall makes sure that deferred probing is delayed until
154 * late_initcall time.
155 */
156static int deferred_probe_initcall(void)
157{
158 deferred_wq = create_singlethread_workqueue("deferwq");
159 if (WARN_ON(!deferred_wq))
160 return -ENOMEM;
161
162 driver_deferred_probe_enable = true;
163 driver_deferred_probe_trigger();
164 return 0;
165}
166late_initcall(deferred_probe_initcall);
167
168static void driver_bound(struct device *dev)
169{
170 if (klist_node_attached(&dev->p->knode_driver)) {
171 printk(KERN_WARNING "%s: device %s already bound\n",
172 __func__, kobject_name(&dev->kobj));
173 return;
174 }
175
176 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev),
177 __func__, dev->driver->name);
178
179 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
180
181 /*
182 * Make sure the device is no longer in one of the deferred lists and
183 * kick off retrying all pending devices
184 */
185 driver_deferred_probe_del(dev);
186 driver_deferred_probe_trigger();
187
188 if (dev->bus)
189 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
190 BUS_NOTIFY_BOUND_DRIVER, dev);
191}
192
193static int driver_sysfs_add(struct device *dev)
194{
195 int ret;
196
197 if (dev->bus)
198 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
199 BUS_NOTIFY_BIND_DRIVER, dev);
200
201 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
202 kobject_name(&dev->kobj));
203 if (ret == 0) {
204 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
205 "driver");
206 if (ret)
207 sysfs_remove_link(&dev->driver->p->kobj,
208 kobject_name(&dev->kobj));
209 }
210 return ret;
211}
212
213static void driver_sysfs_remove(struct device *dev)
214{
215 struct device_driver *drv = dev->driver;
216
217 if (drv) {
218 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
219 sysfs_remove_link(&dev->kobj, "driver");
220 }
221}
222
223/**
224 * device_bind_driver - bind a driver to one device.
225 * @dev: device.
226 *
227 * Allow manual attachment of a driver to a device.
228 * Caller must have already set @dev->driver.
229 *
230 * Note that this does not modify the bus reference count
231 * nor take the bus's rwsem. Please verify those are accounted
232 * for before calling this. (It is ok to call with no other effort
233 * from a driver's probe() method.)
234 *
235 * This function must be called with the device lock held.
236 */
237int device_bind_driver(struct device *dev)
238{
239 int ret;
240
241 ret = driver_sysfs_add(dev);
242 if (!ret)
243 driver_bound(dev);
244 return ret;
245}
246EXPORT_SYMBOL_GPL(device_bind_driver);
247
248static atomic_t probe_count = ATOMIC_INIT(0);
249static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
250
251static int really_probe(struct device *dev, struct device_driver *drv)
252{
253 int ret = 0;
254
255 atomic_inc(&probe_count);
256 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
257 drv->bus->name, __func__, drv->name, dev_name(dev));
258 WARN_ON(!list_empty(&dev->devres_head));
259
260 dev->driver = drv;
261 if (driver_sysfs_add(dev)) {
262 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
263 __func__, dev_name(dev));
264 goto probe_failed;
265 }
266
267 if (dev->bus->probe) {
268 ret = dev->bus->probe(dev);
269 if (ret)
270 goto probe_failed;
271 } else if (drv->probe) {
272 ret = drv->probe(dev);
273 if (ret)
274 goto probe_failed;
275 }
276
277 driver_bound(dev);
278 ret = 1;
279 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
280 drv->bus->name, __func__, dev_name(dev), drv->name);
281 goto done;
282
283probe_failed:
284 devres_release_all(dev);
285 driver_sysfs_remove(dev);
286 dev->driver = NULL;
287
288 if (ret == -EPROBE_DEFER) {
289 /* Driver requested deferred probing */
290 dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
291 driver_deferred_probe_add(dev);
292 } else if (ret != -ENODEV && ret != -ENXIO) {
293 /* driver matched but the probe failed */
294 printk(KERN_WARNING
295 "%s: probe of %s failed with error %d\n",
296 drv->name, dev_name(dev), ret);
297 } else {
298 pr_debug("%s: probe of %s rejects match %d\n",
299 drv->name, dev_name(dev), ret);
300 }
301 /*
302 * Ignore errors returned by ->probe so that the next driver can try
303 * its luck.
304 */
305 ret = 0;
306done:
307 atomic_dec(&probe_count);
308 wake_up(&probe_waitqueue);
309 return ret;
310}
311
312/**
313 * driver_probe_done
314 * Determine if the probe sequence is finished or not.
315 *
316 * Should somehow figure out how to use a semaphore, not an atomic variable...
317 */
318int driver_probe_done(void)
319{
320 pr_debug("%s: probe_count = %d\n", __func__,
321 atomic_read(&probe_count));
322 if (atomic_read(&probe_count))
323 return -EBUSY;
324 return 0;
325}
326
327/**
328 * wait_for_device_probe
329 * Wait for device probing to be completed.
330 */
331void wait_for_device_probe(void)
332{
333 /* wait for the known devices to complete their probing */
334 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
335 async_synchronize_full();
336 scsi_complete_async_scans();
337}
338EXPORT_SYMBOL_GPL(wait_for_device_probe);
339
340/**
341 * driver_probe_device - attempt to bind device & driver together
342 * @drv: driver to bind a device to
343 * @dev: device to try to bind to the driver
344 *
345 * This function returns -ENODEV if the device is not registered,
346 * 1 if the device is bound successfully and 0 otherwise.
347 *
348 * This function must be called with @dev lock held. When called for a
349 * USB interface, @dev->parent lock must be held as well.
350 */
351int driver_probe_device(struct device_driver *drv, struct device *dev)
352{
353 int ret = 0;
354
355 if (!device_is_registered(dev))
356 return -ENODEV;
357
358 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
359 drv->bus->name, __func__, dev_name(dev), drv->name);
360
361 pm_runtime_get_noresume(dev);
362 pm_runtime_barrier(dev);
363 ret = really_probe(dev, drv);
364 pm_runtime_put_sync(dev);
365
366 return ret;
367}
368
369static int __device_attach(struct device_driver *drv, void *data)
370{
371 struct device *dev = data;
372
373 if (!driver_match_device(drv, dev))
374 return 0;
375
376 return driver_probe_device(drv, dev);
377}
378
379/**
380 * device_attach - try to attach device to a driver.
381 * @dev: device.
382 *
383 * Walk the list of drivers that the bus has and call
384 * driver_probe_device() for each pair. If a compatible
385 * pair is found, break out and return.
386 *
387 * Returns 1 if the device was bound to a driver;
388 * 0 if no matching driver was found;
389 * -ENODEV if the device is not registered.
390 *
391 * When called for a USB interface, @dev->parent lock must be held.
392 */
393int device_attach(struct device *dev)
394{
395 int ret = 0;
396
397 device_lock(dev);
398 if (dev->driver) {
399 if (klist_node_attached(&dev->p->knode_driver)) {
400 ret = 1;
401 goto out_unlock;
402 }
403 ret = device_bind_driver(dev);
404 if (ret == 0)
405 ret = 1;
406 else {
407 dev->driver = NULL;
408 ret = 0;
409 }
410 } else {
411 pm_runtime_get_noresume(dev);
412 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
413 pm_runtime_put_sync(dev);
414 }
415out_unlock:
416 device_unlock(dev);
417 return ret;
418}
419EXPORT_SYMBOL_GPL(device_attach);
420
421static int __driver_attach(struct device *dev, void *data)
422{
423 struct device_driver *drv = data;
424
425 /*
426 * Lock device and try to bind to it. We drop the error
427 * here and always return 0, because we need to keep trying
428 * to bind to devices and some drivers will return an error
429 * simply if it didn't support the device.
430 *
431 * driver_probe_device() will spit a warning if there
432 * is an error.
433 */
434
435 if (!driver_match_device(drv, dev))
436 return 0;
437
438 if (dev->parent) /* Needed for USB */
439 device_lock(dev->parent);
440 device_lock(dev);
441 if (!dev->driver)
442 driver_probe_device(drv, dev);
443 device_unlock(dev);
444 if (dev->parent)
445 device_unlock(dev->parent);
446
447 return 0;
448}
449
450/**
451 * driver_attach - try to bind driver to devices.
452 * @drv: driver.
453 *
454 * Walk the list of devices that the bus has on it and try to
455 * match the driver with each one. If driver_probe_device()
456 * returns 0 and the @dev->driver is set, we've found a
457 * compatible pair.
458 */
459int driver_attach(struct device_driver *drv)
460{
461 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
462}
463EXPORT_SYMBOL_GPL(driver_attach);
464
465/*
466 * __device_release_driver() must be called with @dev lock held.
467 * When called for a USB interface, @dev->parent lock must be held as well.
468 */
469static void __device_release_driver(struct device *dev)
470{
471 struct device_driver *drv;
472
473 drv = dev->driver;
474 if (drv) {
475 pm_runtime_get_sync(dev);
476
477 driver_sysfs_remove(dev);
478
479 if (dev->bus)
480 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
481 BUS_NOTIFY_UNBIND_DRIVER,
482 dev);
483
484 pm_runtime_put_sync(dev);
485
486 if (dev->bus && dev->bus->remove)
487 dev->bus->remove(dev);
488 else if (drv->remove)
489 drv->remove(dev);
490 devres_release_all(dev);
491 dev->driver = NULL;
492 klist_remove(&dev->p->knode_driver);
493 if (dev->bus)
494 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
495 BUS_NOTIFY_UNBOUND_DRIVER,
496 dev);
497
498 }
499}
500
501/**
502 * device_release_driver - manually detach device from driver.
503 * @dev: device.
504 *
505 * Manually detach device from driver.
506 * When called for a USB interface, @dev->parent lock must be held.
507 */
508void device_release_driver(struct device *dev)
509{
510 /*
511 * If anyone calls device_release_driver() recursively from
512 * within their ->remove callback for the same device, they
513 * will deadlock right here.
514 */
515 device_lock(dev);
516 __device_release_driver(dev);
517 device_unlock(dev);
518}
519EXPORT_SYMBOL_GPL(device_release_driver);
520
521/**
522 * driver_detach - detach driver from all devices it controls.
523 * @drv: driver.
524 */
525void driver_detach(struct device_driver *drv)
526{
527 struct device_private *dev_prv;
528 struct device *dev;
529
530 for (;;) {
531 spin_lock(&drv->p->klist_devices.k_lock);
532 if (list_empty(&drv->p->klist_devices.k_list)) {
533 spin_unlock(&drv->p->klist_devices.k_lock);
534 break;
535 }
536 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
537 struct device_private,
538 knode_driver.n_node);
539 dev = dev_prv->device;
540 get_device(dev);
541 spin_unlock(&drv->p->klist_devices.k_lock);
542
543 if (dev->parent) /* Needed for USB */
544 device_lock(dev->parent);
545 device_lock(dev);
546 if (dev->driver == drv)
547 __device_release_driver(dev);
548 device_unlock(dev);
549 if (dev->parent)
550 device_unlock(dev->parent);
551 put_device(dev);
552 }
553}
554
555/*
556 * These exports can't be _GPL due to .h files using this within them, and it
557 * might break something that was previously working...
558 */
559void *dev_get_drvdata(const struct device *dev)
560{
561 if (dev && dev->p)
562 return dev->p->driver_data;
563 return NULL;
564}
565EXPORT_SYMBOL(dev_get_drvdata);
566
567int dev_set_drvdata(struct device *dev, void *data)
568{
569 int error;
570
571 if (!dev->p) {
572 error = device_private_init(dev);
573 if (error)
574 return error;
575 }
576 dev->p->driver_data = data;
577 return 0;
578}
579EXPORT_SYMBOL(dev_set_drvdata);