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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 <linux/pinctrl/devinfo.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 atomic_t deferred_trigger_count = ATOMIC_INIT(0);
55
56/*
57 * In some cases, like suspend to RAM or hibernation, It might be reasonable
58 * to prohibit probing of devices as it could be unsafe.
59 * Once defer_all_probes is true all drivers probes will be forcibly deferred.
60 */
61static bool defer_all_probes;
62
63/*
64 * deferred_probe_work_func() - Retry probing devices in the active list.
65 */
66static void deferred_probe_work_func(struct work_struct *work)
67{
68 struct device *dev;
69 struct device_private *private;
70 /*
71 * This block processes every device in the deferred 'active' list.
72 * Each device is removed from the active list and passed to
73 * bus_probe_device() to re-attempt the probe. The loop continues
74 * until every device in the active list is removed and retried.
75 *
76 * Note: Once the device is removed from the list and the mutex is
77 * released, it is possible for the device get freed by another thread
78 * and cause a illegal pointer dereference. This code uses
79 * get/put_device() to ensure the device structure cannot disappear
80 * from under our feet.
81 */
82 mutex_lock(&deferred_probe_mutex);
83 while (!list_empty(&deferred_probe_active_list)) {
84 private = list_first_entry(&deferred_probe_active_list,
85 typeof(*dev->p), deferred_probe);
86 dev = private->device;
87 list_del_init(&private->deferred_probe);
88
89 get_device(dev);
90
91 /*
92 * Drop the mutex while probing each device; the probe path may
93 * manipulate the deferred list
94 */
95 mutex_unlock(&deferred_probe_mutex);
96
97 /*
98 * Force the device to the end of the dpm_list since
99 * the PM code assumes that the order we add things to
100 * the list is a good order for suspend but deferred
101 * probe makes that very unsafe.
102 */
103 device_pm_lock();
104 device_pm_move_last(dev);
105 device_pm_unlock();
106
107 dev_dbg(dev, "Retrying from deferred list\n");
108 bus_probe_device(dev);
109
110 mutex_lock(&deferred_probe_mutex);
111
112 put_device(dev);
113 }
114 mutex_unlock(&deferred_probe_mutex);
115}
116static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
117
118static void driver_deferred_probe_add(struct device *dev)
119{
120 mutex_lock(&deferred_probe_mutex);
121 if (list_empty(&dev->p->deferred_probe)) {
122 dev_dbg(dev, "Added to deferred list\n");
123 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
124 }
125 mutex_unlock(&deferred_probe_mutex);
126}
127
128void driver_deferred_probe_del(struct device *dev)
129{
130 mutex_lock(&deferred_probe_mutex);
131 if (!list_empty(&dev->p->deferred_probe)) {
132 dev_dbg(dev, "Removed from deferred list\n");
133 list_del_init(&dev->p->deferred_probe);
134 }
135 mutex_unlock(&deferred_probe_mutex);
136}
137
138static bool driver_deferred_probe_enable = false;
139/**
140 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
141 *
142 * This functions moves all devices from the pending list to the active
143 * list and schedules the deferred probe workqueue to process them. It
144 * should be called anytime a driver is successfully bound to a device.
145 *
146 * Note, there is a race condition in multi-threaded probe. In the case where
147 * more than one device is probing at the same time, it is possible for one
148 * probe to complete successfully while another is about to defer. If the second
149 * depends on the first, then it will get put on the pending list after the
150 * trigger event has already occurred and will be stuck there.
151 *
152 * The atomic 'deferred_trigger_count' is used to determine if a successful
153 * trigger has occurred in the midst of probing a driver. If the trigger count
154 * changes in the midst of a probe, then deferred processing should be triggered
155 * again.
156 */
157static void driver_deferred_probe_trigger(void)
158{
159 if (!driver_deferred_probe_enable)
160 return;
161
162 /*
163 * A successful probe means that all the devices in the pending list
164 * should be triggered to be reprobed. Move all the deferred devices
165 * into the active list so they can be retried by the workqueue
166 */
167 mutex_lock(&deferred_probe_mutex);
168 atomic_inc(&deferred_trigger_count);
169 list_splice_tail_init(&deferred_probe_pending_list,
170 &deferred_probe_active_list);
171 mutex_unlock(&deferred_probe_mutex);
172
173 /*
174 * Kick the re-probe thread. It may already be scheduled, but it is
175 * safe to kick it again.
176 */
177 schedule_work(&deferred_probe_work);
178}
179
180/**
181 * device_block_probing() - Block/defere device's probes
182 *
183 * It will disable probing of devices and defer their probes instead.
184 */
185void device_block_probing(void)
186{
187 defer_all_probes = true;
188 /* sync with probes to avoid races. */
189 wait_for_device_probe();
190}
191
192/**
193 * device_unblock_probing() - Unblock/enable device's probes
194 *
195 * It will restore normal behavior and trigger re-probing of deferred
196 * devices.
197 */
198void device_unblock_probing(void)
199{
200 defer_all_probes = false;
201 driver_deferred_probe_trigger();
202}
203
204/**
205 * deferred_probe_initcall() - Enable probing of deferred devices
206 *
207 * We don't want to get in the way when the bulk of drivers are getting probed.
208 * Instead, this initcall makes sure that deferred probing is delayed until
209 * late_initcall time.
210 */
211static int deferred_probe_initcall(void)
212{
213 driver_deferred_probe_enable = true;
214 driver_deferred_probe_trigger();
215 /* Sort as many dependencies as possible before exiting initcalls */
216 flush_work(&deferred_probe_work);
217 return 0;
218}
219late_initcall(deferred_probe_initcall);
220
221/**
222 * device_is_bound() - Check if device is bound to a driver
223 * @dev: device to check
224 *
225 * Returns true if passed device has already finished probing successfully
226 * against a driver.
227 *
228 * This function must be called with the device lock held.
229 */
230bool device_is_bound(struct device *dev)
231{
232 return dev->p && klist_node_attached(&dev->p->knode_driver);
233}
234
235static void driver_bound(struct device *dev)
236{
237 if (device_is_bound(dev)) {
238 printk(KERN_WARNING "%s: device %s already bound\n",
239 __func__, kobject_name(&dev->kobj));
240 return;
241 }
242
243 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
244 __func__, dev_name(dev));
245
246 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
247 device_links_driver_bound(dev);
248
249 device_pm_check_callbacks(dev);
250
251 /*
252 * Make sure the device is no longer in one of the deferred lists and
253 * kick off retrying all pending devices
254 */
255 driver_deferred_probe_del(dev);
256 driver_deferred_probe_trigger();
257
258 if (dev->bus)
259 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
260 BUS_NOTIFY_BOUND_DRIVER, dev);
261}
262
263static int driver_sysfs_add(struct device *dev)
264{
265 int ret;
266
267 if (dev->bus)
268 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
269 BUS_NOTIFY_BIND_DRIVER, dev);
270
271 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
272 kobject_name(&dev->kobj));
273 if (ret == 0) {
274 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
275 "driver");
276 if (ret)
277 sysfs_remove_link(&dev->driver->p->kobj,
278 kobject_name(&dev->kobj));
279 }
280 return ret;
281}
282
283static void driver_sysfs_remove(struct device *dev)
284{
285 struct device_driver *drv = dev->driver;
286
287 if (drv) {
288 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
289 sysfs_remove_link(&dev->kobj, "driver");
290 }
291}
292
293/**
294 * device_bind_driver - bind a driver to one device.
295 * @dev: device.
296 *
297 * Allow manual attachment of a driver to a device.
298 * Caller must have already set @dev->driver.
299 *
300 * Note that this does not modify the bus reference count
301 * nor take the bus's rwsem. Please verify those are accounted
302 * for before calling this. (It is ok to call with no other effort
303 * from a driver's probe() method.)
304 *
305 * This function must be called with the device lock held.
306 */
307int device_bind_driver(struct device *dev)
308{
309 int ret;
310
311 ret = driver_sysfs_add(dev);
312 if (!ret)
313 driver_bound(dev);
314 else if (dev->bus)
315 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
316 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
317 return ret;
318}
319EXPORT_SYMBOL_GPL(device_bind_driver);
320
321static atomic_t probe_count = ATOMIC_INIT(0);
322static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
323
324static int really_probe(struct device *dev, struct device_driver *drv)
325{
326 int ret = -EPROBE_DEFER;
327 int local_trigger_count = atomic_read(&deferred_trigger_count);
328 bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
329 !drv->suppress_bind_attrs;
330
331 if (defer_all_probes) {
332 /*
333 * Value of defer_all_probes can be set only by
334 * device_defer_all_probes_enable() which, in turn, will call
335 * wait_for_device_probe() right after that to avoid any races.
336 */
337 dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
338 driver_deferred_probe_add(dev);
339 return ret;
340 }
341
342 ret = device_links_check_suppliers(dev);
343 if (ret)
344 return ret;
345
346 atomic_inc(&probe_count);
347 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
348 drv->bus->name, __func__, drv->name, dev_name(dev));
349 WARN_ON(!list_empty(&dev->devres_head));
350
351re_probe:
352 dev->driver = drv;
353
354 /* If using pinctrl, bind pins now before probing */
355 ret = pinctrl_bind_pins(dev);
356 if (ret)
357 goto pinctrl_bind_failed;
358
359 if (driver_sysfs_add(dev)) {
360 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
361 __func__, dev_name(dev));
362 goto probe_failed;
363 }
364
365 if (dev->pm_domain && dev->pm_domain->activate) {
366 ret = dev->pm_domain->activate(dev);
367 if (ret)
368 goto probe_failed;
369 }
370
371 /*
372 * Ensure devices are listed in devices_kset in correct order
373 * It's important to move Dev to the end of devices_kset before
374 * calling .probe, because it could be recursive and parent Dev
375 * should always go first
376 */
377 devices_kset_move_last(dev);
378
379 if (dev->bus->probe) {
380 ret = dev->bus->probe(dev);
381 if (ret)
382 goto probe_failed;
383 } else if (drv->probe) {
384 ret = drv->probe(dev);
385 if (ret)
386 goto probe_failed;
387 }
388
389 if (test_remove) {
390 test_remove = false;
391
392 if (dev->bus->remove)
393 dev->bus->remove(dev);
394 else if (drv->remove)
395 drv->remove(dev);
396
397 devres_release_all(dev);
398 driver_sysfs_remove(dev);
399 dev->driver = NULL;
400 dev_set_drvdata(dev, NULL);
401 if (dev->pm_domain && dev->pm_domain->dismiss)
402 dev->pm_domain->dismiss(dev);
403 pm_runtime_reinit(dev);
404
405 goto re_probe;
406 }
407
408 pinctrl_init_done(dev);
409
410 if (dev->pm_domain && dev->pm_domain->sync)
411 dev->pm_domain->sync(dev);
412
413 driver_bound(dev);
414 ret = 1;
415 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
416 drv->bus->name, __func__, dev_name(dev), drv->name);
417 goto done;
418
419probe_failed:
420 if (dev->bus)
421 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
422 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
423pinctrl_bind_failed:
424 device_links_no_driver(dev);
425 devres_release_all(dev);
426 driver_sysfs_remove(dev);
427 dev->driver = NULL;
428 dev_set_drvdata(dev, NULL);
429 if (dev->pm_domain && dev->pm_domain->dismiss)
430 dev->pm_domain->dismiss(dev);
431 pm_runtime_reinit(dev);
432
433 switch (ret) {
434 case -EPROBE_DEFER:
435 /* Driver requested deferred probing */
436 dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
437 driver_deferred_probe_add(dev);
438 /* Did a trigger occur while probing? Need to re-trigger if yes */
439 if (local_trigger_count != atomic_read(&deferred_trigger_count))
440 driver_deferred_probe_trigger();
441 break;
442 case -ENODEV:
443 case -ENXIO:
444 pr_debug("%s: probe of %s rejects match %d\n",
445 drv->name, dev_name(dev), ret);
446 break;
447 default:
448 /* driver matched but the probe failed */
449 printk(KERN_WARNING
450 "%s: probe of %s failed with error %d\n",
451 drv->name, dev_name(dev), ret);
452 }
453 /*
454 * Ignore errors returned by ->probe so that the next driver can try
455 * its luck.
456 */
457 ret = 0;
458done:
459 atomic_dec(&probe_count);
460 wake_up(&probe_waitqueue);
461 return ret;
462}
463
464/**
465 * driver_probe_done
466 * Determine if the probe sequence is finished or not.
467 *
468 * Should somehow figure out how to use a semaphore, not an atomic variable...
469 */
470int driver_probe_done(void)
471{
472 pr_debug("%s: probe_count = %d\n", __func__,
473 atomic_read(&probe_count));
474 if (atomic_read(&probe_count))
475 return -EBUSY;
476 return 0;
477}
478
479/**
480 * wait_for_device_probe
481 * Wait for device probing to be completed.
482 */
483void wait_for_device_probe(void)
484{
485 /* wait for the deferred probe workqueue to finish */
486 flush_work(&deferred_probe_work);
487
488 /* wait for the known devices to complete their probing */
489 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
490 async_synchronize_full();
491}
492EXPORT_SYMBOL_GPL(wait_for_device_probe);
493
494/**
495 * driver_probe_device - attempt to bind device & driver together
496 * @drv: driver to bind a device to
497 * @dev: device to try to bind to the driver
498 *
499 * This function returns -ENODEV if the device is not registered,
500 * 1 if the device is bound successfully and 0 otherwise.
501 *
502 * This function must be called with @dev lock held. When called for a
503 * USB interface, @dev->parent lock must be held as well.
504 *
505 * If the device has a parent, runtime-resume the parent before driver probing.
506 */
507int driver_probe_device(struct device_driver *drv, struct device *dev)
508{
509 int ret = 0;
510
511 if (!device_is_registered(dev))
512 return -ENODEV;
513
514 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
515 drv->bus->name, __func__, dev_name(dev), drv->name);
516
517 pm_runtime_get_suppliers(dev);
518 if (dev->parent)
519 pm_runtime_get_sync(dev->parent);
520
521 pm_runtime_barrier(dev);
522 ret = really_probe(dev, drv);
523 pm_request_idle(dev);
524
525 if (dev->parent)
526 pm_runtime_put(dev->parent);
527
528 pm_runtime_put_suppliers(dev);
529 return ret;
530}
531
532bool driver_allows_async_probing(struct device_driver *drv)
533{
534 switch (drv->probe_type) {
535 case PROBE_PREFER_ASYNCHRONOUS:
536 return true;
537
538 case PROBE_FORCE_SYNCHRONOUS:
539 return false;
540
541 default:
542 if (module_requested_async_probing(drv->owner))
543 return true;
544
545 return false;
546 }
547}
548
549struct device_attach_data {
550 struct device *dev;
551
552 /*
553 * Indicates whether we are are considering asynchronous probing or
554 * not. Only initial binding after device or driver registration
555 * (including deferral processing) may be done asynchronously, the
556 * rest is always synchronous, as we expect it is being done by
557 * request from userspace.
558 */
559 bool check_async;
560
561 /*
562 * Indicates if we are binding synchronous or asynchronous drivers.
563 * When asynchronous probing is enabled we'll execute 2 passes
564 * over drivers: first pass doing synchronous probing and second
565 * doing asynchronous probing (if synchronous did not succeed -
566 * most likely because there was no driver requiring synchronous
567 * probing - and we found asynchronous driver during first pass).
568 * The 2 passes are done because we can't shoot asynchronous
569 * probe for given device and driver from bus_for_each_drv() since
570 * driver pointer is not guaranteed to stay valid once
571 * bus_for_each_drv() iterates to the next driver on the bus.
572 */
573 bool want_async;
574
575 /*
576 * We'll set have_async to 'true' if, while scanning for matching
577 * driver, we'll encounter one that requests asynchronous probing.
578 */
579 bool have_async;
580};
581
582static int __device_attach_driver(struct device_driver *drv, void *_data)
583{
584 struct device_attach_data *data = _data;
585 struct device *dev = data->dev;
586 bool async_allowed;
587 int ret;
588
589 /*
590 * Check if device has already been claimed. This may
591 * happen with driver loading, device discovery/registration,
592 * and deferred probe processing happens all at once with
593 * multiple threads.
594 */
595 if (dev->driver)
596 return -EBUSY;
597
598 ret = driver_match_device(drv, dev);
599 if (ret == 0) {
600 /* no match */
601 return 0;
602 } else if (ret == -EPROBE_DEFER) {
603 dev_dbg(dev, "Device match requests probe deferral\n");
604 driver_deferred_probe_add(dev);
605 } else if (ret < 0) {
606 dev_dbg(dev, "Bus failed to match device: %d", ret);
607 return ret;
608 } /* ret > 0 means positive match */
609
610 async_allowed = driver_allows_async_probing(drv);
611
612 if (async_allowed)
613 data->have_async = true;
614
615 if (data->check_async && async_allowed != data->want_async)
616 return 0;
617
618 return driver_probe_device(drv, dev);
619}
620
621static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
622{
623 struct device *dev = _dev;
624 struct device_attach_data data = {
625 .dev = dev,
626 .check_async = true,
627 .want_async = true,
628 };
629
630 device_lock(dev);
631
632 if (dev->parent)
633 pm_runtime_get_sync(dev->parent);
634
635 bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
636 dev_dbg(dev, "async probe completed\n");
637
638 pm_request_idle(dev);
639
640 if (dev->parent)
641 pm_runtime_put(dev->parent);
642
643 device_unlock(dev);
644
645 put_device(dev);
646}
647
648static int __device_attach(struct device *dev, bool allow_async)
649{
650 int ret = 0;
651
652 device_lock(dev);
653 if (dev->driver) {
654 if (device_is_bound(dev)) {
655 ret = 1;
656 goto out_unlock;
657 }
658 ret = device_bind_driver(dev);
659 if (ret == 0)
660 ret = 1;
661 else {
662 dev->driver = NULL;
663 ret = 0;
664 }
665 } else {
666 struct device_attach_data data = {
667 .dev = dev,
668 .check_async = allow_async,
669 .want_async = false,
670 };
671
672 if (dev->parent)
673 pm_runtime_get_sync(dev->parent);
674
675 ret = bus_for_each_drv(dev->bus, NULL, &data,
676 __device_attach_driver);
677 if (!ret && allow_async && data.have_async) {
678 /*
679 * If we could not find appropriate driver
680 * synchronously and we are allowed to do
681 * async probes and there are drivers that
682 * want to probe asynchronously, we'll
683 * try them.
684 */
685 dev_dbg(dev, "scheduling asynchronous probe\n");
686 get_device(dev);
687 async_schedule(__device_attach_async_helper, dev);
688 } else {
689 pm_request_idle(dev);
690 }
691
692 if (dev->parent)
693 pm_runtime_put(dev->parent);
694 }
695out_unlock:
696 device_unlock(dev);
697 return ret;
698}
699
700/**
701 * device_attach - try to attach device to a driver.
702 * @dev: device.
703 *
704 * Walk the list of drivers that the bus has and call
705 * driver_probe_device() for each pair. If a compatible
706 * pair is found, break out and return.
707 *
708 * Returns 1 if the device was bound to a driver;
709 * 0 if no matching driver was found;
710 * -ENODEV if the device is not registered.
711 *
712 * When called for a USB interface, @dev->parent lock must be held.
713 */
714int device_attach(struct device *dev)
715{
716 return __device_attach(dev, false);
717}
718EXPORT_SYMBOL_GPL(device_attach);
719
720void device_initial_probe(struct device *dev)
721{
722 __device_attach(dev, true);
723}
724
725static int __driver_attach(struct device *dev, void *data)
726{
727 struct device_driver *drv = data;
728 int ret;
729
730 /*
731 * Lock device and try to bind to it. We drop the error
732 * here and always return 0, because we need to keep trying
733 * to bind to devices and some drivers will return an error
734 * simply if it didn't support the device.
735 *
736 * driver_probe_device() will spit a warning if there
737 * is an error.
738 */
739
740 ret = driver_match_device(drv, dev);
741 if (ret == 0) {
742 /* no match */
743 return 0;
744 } else if (ret == -EPROBE_DEFER) {
745 dev_dbg(dev, "Device match requests probe deferral\n");
746 driver_deferred_probe_add(dev);
747 } else if (ret < 0) {
748 dev_dbg(dev, "Bus failed to match device: %d", ret);
749 return ret;
750 } /* ret > 0 means positive match */
751
752 if (dev->parent) /* Needed for USB */
753 device_lock(dev->parent);
754 device_lock(dev);
755 if (!dev->driver)
756 driver_probe_device(drv, dev);
757 device_unlock(dev);
758 if (dev->parent)
759 device_unlock(dev->parent);
760
761 return 0;
762}
763
764/**
765 * driver_attach - try to bind driver to devices.
766 * @drv: driver.
767 *
768 * Walk the list of devices that the bus has on it and try to
769 * match the driver with each one. If driver_probe_device()
770 * returns 0 and the @dev->driver is set, we've found a
771 * compatible pair.
772 */
773int driver_attach(struct device_driver *drv)
774{
775 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
776}
777EXPORT_SYMBOL_GPL(driver_attach);
778
779/*
780 * __device_release_driver() must be called with @dev lock held.
781 * When called for a USB interface, @dev->parent lock must be held as well.
782 */
783static void __device_release_driver(struct device *dev, struct device *parent)
784{
785 struct device_driver *drv;
786
787 drv = dev->driver;
788 if (drv) {
789 if (driver_allows_async_probing(drv))
790 async_synchronize_full();
791
792 while (device_links_busy(dev)) {
793 device_unlock(dev);
794 if (parent)
795 device_unlock(parent);
796
797 device_links_unbind_consumers(dev);
798 if (parent)
799 device_lock(parent);
800
801 device_lock(dev);
802 /*
803 * A concurrent invocation of the same function might
804 * have released the driver successfully while this one
805 * was waiting, so check for that.
806 */
807 if (dev->driver != drv)
808 return;
809 }
810
811 pm_runtime_get_sync(dev);
812 pm_runtime_clean_up_links(dev);
813
814 driver_sysfs_remove(dev);
815
816 if (dev->bus)
817 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
818 BUS_NOTIFY_UNBIND_DRIVER,
819 dev);
820
821 pm_runtime_put_sync(dev);
822
823 if (dev->bus && dev->bus->remove)
824 dev->bus->remove(dev);
825 else if (drv->remove)
826 drv->remove(dev);
827
828 device_links_driver_cleanup(dev);
829 devres_release_all(dev);
830 dev->driver = NULL;
831 dev_set_drvdata(dev, NULL);
832 if (dev->pm_domain && dev->pm_domain->dismiss)
833 dev->pm_domain->dismiss(dev);
834 pm_runtime_reinit(dev);
835
836 klist_remove(&dev->p->knode_driver);
837 device_pm_check_callbacks(dev);
838 if (dev->bus)
839 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
840 BUS_NOTIFY_UNBOUND_DRIVER,
841 dev);
842 }
843}
844
845void device_release_driver_internal(struct device *dev,
846 struct device_driver *drv,
847 struct device *parent)
848{
849 if (parent)
850 device_lock(parent);
851
852 device_lock(dev);
853 if (!drv || drv == dev->driver)
854 __device_release_driver(dev, parent);
855
856 device_unlock(dev);
857 if (parent)
858 device_unlock(parent);
859}
860
861/**
862 * device_release_driver - manually detach device from driver.
863 * @dev: device.
864 *
865 * Manually detach device from driver.
866 * When called for a USB interface, @dev->parent lock must be held.
867 *
868 * If this function is to be called with @dev->parent lock held, ensure that
869 * the device's consumers are unbound in advance or that their locks can be
870 * acquired under the @dev->parent lock.
871 */
872void device_release_driver(struct device *dev)
873{
874 /*
875 * If anyone calls device_release_driver() recursively from
876 * within their ->remove callback for the same device, they
877 * will deadlock right here.
878 */
879 device_release_driver_internal(dev, NULL, NULL);
880}
881EXPORT_SYMBOL_GPL(device_release_driver);
882
883/**
884 * driver_detach - detach driver from all devices it controls.
885 * @drv: driver.
886 */
887void driver_detach(struct device_driver *drv)
888{
889 struct device_private *dev_prv;
890 struct device *dev;
891
892 for (;;) {
893 spin_lock(&drv->p->klist_devices.k_lock);
894 if (list_empty(&drv->p->klist_devices.k_list)) {
895 spin_unlock(&drv->p->klist_devices.k_lock);
896 break;
897 }
898 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
899 struct device_private,
900 knode_driver.n_node);
901 dev = dev_prv->device;
902 get_device(dev);
903 spin_unlock(&drv->p->klist_devices.k_lock);
904 device_release_driver_internal(dev, drv, dev->parent);
905 put_device(dev);
906 }
907}