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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/dd.c - The core device/driver interactions.
4 *
5 * This file contains the (sometimes tricky) code that controls the
6 * interactions between devices and drivers, which primarily includes
7 * driver binding and unbinding.
8 *
9 * All of this code used to exist in drivers/base/bus.c, but was
10 * relocated to here in the name of compartmentalization (since it wasn't
11 * strictly code just for the 'struct bus_type'.
12 *
13 * Copyright (c) 2002-5 Patrick Mochel
14 * Copyright (c) 2002-3 Open Source Development Labs
15 * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
16 * Copyright (c) 2007-2009 Novell Inc.
17 */
18
19#include <linux/debugfs.h>
20#include <linux/device.h>
21#include <linux/delay.h>
22#include <linux/dma-map-ops.h>
23#include <linux/init.h>
24#include <linux/module.h>
25#include <linux/kthread.h>
26#include <linux/wait.h>
27#include <linux/async.h>
28#include <linux/pm_runtime.h>
29#include <linux/pinctrl/devinfo.h>
30#include <linux/slab.h>
31
32#include "base.h"
33#include "power/power.h"
34
35/*
36 * Deferred Probe infrastructure.
37 *
38 * Sometimes driver probe order matters, but the kernel doesn't always have
39 * dependency information which means some drivers will get probed before a
40 * resource it depends on is available. For example, an SDHCI driver may
41 * first need a GPIO line from an i2c GPIO controller before it can be
42 * initialized. If a required resource is not available yet, a driver can
43 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
44 *
45 * Deferred probe maintains two lists of devices, a pending list and an active
46 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
47 * pending list. A successful driver probe will trigger moving all devices
48 * from the pending to the active list so that the workqueue will eventually
49 * retry them.
50 *
51 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
52 * of the (struct device*)->p->deferred_probe pointers are manipulated
53 */
54static DEFINE_MUTEX(deferred_probe_mutex);
55static LIST_HEAD(deferred_probe_pending_list);
56static LIST_HEAD(deferred_probe_active_list);
57static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
58static bool initcalls_done;
59
60/* Save the async probe drivers' name from kernel cmdline */
61#define ASYNC_DRV_NAMES_MAX_LEN 256
62static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
63
64/*
65 * In some cases, like suspend to RAM or hibernation, It might be reasonable
66 * to prohibit probing of devices as it could be unsafe.
67 * Once defer_all_probes is true all drivers probes will be forcibly deferred.
68 */
69static bool defer_all_probes;
70
71static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
72{
73 kfree(dev->p->deferred_probe_reason);
74 dev->p->deferred_probe_reason = reason;
75}
76
77/*
78 * deferred_probe_work_func() - Retry probing devices in the active list.
79 */
80static void deferred_probe_work_func(struct work_struct *work)
81{
82 struct device *dev;
83 struct device_private *private;
84 /*
85 * This block processes every device in the deferred 'active' list.
86 * Each device is removed from the active list and passed to
87 * bus_probe_device() to re-attempt the probe. The loop continues
88 * until every device in the active list is removed and retried.
89 *
90 * Note: Once the device is removed from the list and the mutex is
91 * released, it is possible for the device get freed by another thread
92 * and cause a illegal pointer dereference. This code uses
93 * get/put_device() to ensure the device structure cannot disappear
94 * from under our feet.
95 */
96 mutex_lock(&deferred_probe_mutex);
97 while (!list_empty(&deferred_probe_active_list)) {
98 private = list_first_entry(&deferred_probe_active_list,
99 typeof(*dev->p), deferred_probe);
100 dev = private->device;
101 list_del_init(&private->deferred_probe);
102
103 get_device(dev);
104
105 __device_set_deferred_probe_reason(dev, NULL);
106
107 /*
108 * Drop the mutex while probing each device; the probe path may
109 * manipulate the deferred list
110 */
111 mutex_unlock(&deferred_probe_mutex);
112
113 /*
114 * Force the device to the end of the dpm_list since
115 * the PM code assumes that the order we add things to
116 * the list is a good order for suspend but deferred
117 * probe makes that very unsafe.
118 */
119 device_pm_move_to_tail(dev);
120
121 dev_dbg(dev, "Retrying from deferred list\n");
122 bus_probe_device(dev);
123 mutex_lock(&deferred_probe_mutex);
124
125 put_device(dev);
126 }
127 mutex_unlock(&deferred_probe_mutex);
128}
129static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
130
131void driver_deferred_probe_add(struct device *dev)
132{
133 if (!dev->can_match)
134 return;
135
136 mutex_lock(&deferred_probe_mutex);
137 if (list_empty(&dev->p->deferred_probe)) {
138 dev_dbg(dev, "Added to deferred list\n");
139 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
140 }
141 mutex_unlock(&deferred_probe_mutex);
142}
143
144void driver_deferred_probe_del(struct device *dev)
145{
146 mutex_lock(&deferred_probe_mutex);
147 if (!list_empty(&dev->p->deferred_probe)) {
148 dev_dbg(dev, "Removed from deferred list\n");
149 list_del_init(&dev->p->deferred_probe);
150 __device_set_deferred_probe_reason(dev, NULL);
151 }
152 mutex_unlock(&deferred_probe_mutex);
153}
154
155static bool driver_deferred_probe_enable = false;
156/**
157 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
158 *
159 * This functions moves all devices from the pending list to the active
160 * list and schedules the deferred probe workqueue to process them. It
161 * should be called anytime a driver is successfully bound to a device.
162 *
163 * Note, there is a race condition in multi-threaded probe. In the case where
164 * more than one device is probing at the same time, it is possible for one
165 * probe to complete successfully while another is about to defer. If the second
166 * depends on the first, then it will get put on the pending list after the
167 * trigger event has already occurred and will be stuck there.
168 *
169 * The atomic 'deferred_trigger_count' is used to determine if a successful
170 * trigger has occurred in the midst of probing a driver. If the trigger count
171 * changes in the midst of a probe, then deferred processing should be triggered
172 * again.
173 */
174static void driver_deferred_probe_trigger(void)
175{
176 if (!driver_deferred_probe_enable)
177 return;
178
179 /*
180 * A successful probe means that all the devices in the pending list
181 * should be triggered to be reprobed. Move all the deferred devices
182 * into the active list so they can be retried by the workqueue
183 */
184 mutex_lock(&deferred_probe_mutex);
185 atomic_inc(&deferred_trigger_count);
186 list_splice_tail_init(&deferred_probe_pending_list,
187 &deferred_probe_active_list);
188 mutex_unlock(&deferred_probe_mutex);
189
190 /*
191 * Kick the re-probe thread. It may already be scheduled, but it is
192 * safe to kick it again.
193 */
194 queue_work(system_unbound_wq, &deferred_probe_work);
195}
196
197/**
198 * device_block_probing() - Block/defer device's probes
199 *
200 * It will disable probing of devices and defer their probes instead.
201 */
202void device_block_probing(void)
203{
204 defer_all_probes = true;
205 /* sync with probes to avoid races. */
206 wait_for_device_probe();
207}
208
209/**
210 * device_unblock_probing() - Unblock/enable device's probes
211 *
212 * It will restore normal behavior and trigger re-probing of deferred
213 * devices.
214 */
215void device_unblock_probing(void)
216{
217 defer_all_probes = false;
218 driver_deferred_probe_trigger();
219}
220
221/**
222 * device_set_deferred_probe_reason() - Set defer probe reason message for device
223 * @dev: the pointer to the struct device
224 * @vaf: the pointer to va_format structure with message
225 */
226void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
227{
228 const char *drv = dev_driver_string(dev);
229 char *reason;
230
231 mutex_lock(&deferred_probe_mutex);
232
233 reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
234 __device_set_deferred_probe_reason(dev, reason);
235
236 mutex_unlock(&deferred_probe_mutex);
237}
238
239/*
240 * deferred_devs_show() - Show the devices in the deferred probe pending list.
241 */
242static int deferred_devs_show(struct seq_file *s, void *data)
243{
244 struct device_private *curr;
245
246 mutex_lock(&deferred_probe_mutex);
247
248 list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
249 seq_printf(s, "%s\t%s", dev_name(curr->device),
250 curr->device->p->deferred_probe_reason ?: "\n");
251
252 mutex_unlock(&deferred_probe_mutex);
253
254 return 0;
255}
256DEFINE_SHOW_ATTRIBUTE(deferred_devs);
257
258int driver_deferred_probe_timeout;
259EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout);
260static DECLARE_WAIT_QUEUE_HEAD(probe_timeout_waitqueue);
261
262static int __init deferred_probe_timeout_setup(char *str)
263{
264 int timeout;
265
266 if (!kstrtoint(str, 10, &timeout))
267 driver_deferred_probe_timeout = timeout;
268 return 1;
269}
270__setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
271
272/**
273 * driver_deferred_probe_check_state() - Check deferred probe state
274 * @dev: device to check
275 *
276 * Return:
277 * -ENODEV if initcalls have completed and modules are disabled.
278 * -ETIMEDOUT if the deferred probe timeout was set and has expired
279 * and modules are enabled.
280 * -EPROBE_DEFER in other cases.
281 *
282 * Drivers or subsystems can opt-in to calling this function instead of directly
283 * returning -EPROBE_DEFER.
284 */
285int driver_deferred_probe_check_state(struct device *dev)
286{
287 if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
288 dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
289 return -ENODEV;
290 }
291
292 if (!driver_deferred_probe_timeout && initcalls_done) {
293 dev_warn(dev, "deferred probe timeout, ignoring dependency\n");
294 return -ETIMEDOUT;
295 }
296
297 return -EPROBE_DEFER;
298}
299
300static void deferred_probe_timeout_work_func(struct work_struct *work)
301{
302 struct device_private *p;
303
304 fw_devlink_drivers_done();
305
306 driver_deferred_probe_timeout = 0;
307 driver_deferred_probe_trigger();
308 flush_work(&deferred_probe_work);
309
310 mutex_lock(&deferred_probe_mutex);
311 list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
312 dev_info(p->device, "deferred probe pending\n");
313 mutex_unlock(&deferred_probe_mutex);
314 wake_up_all(&probe_timeout_waitqueue);
315}
316static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
317
318/**
319 * deferred_probe_initcall() - Enable probing of deferred devices
320 *
321 * We don't want to get in the way when the bulk of drivers are getting probed.
322 * Instead, this initcall makes sure that deferred probing is delayed until
323 * late_initcall time.
324 */
325static int deferred_probe_initcall(void)
326{
327 debugfs_create_file("devices_deferred", 0444, NULL, NULL,
328 &deferred_devs_fops);
329
330 driver_deferred_probe_enable = true;
331 driver_deferred_probe_trigger();
332 /* Sort as many dependencies as possible before exiting initcalls */
333 flush_work(&deferred_probe_work);
334 initcalls_done = true;
335
336 if (!IS_ENABLED(CONFIG_MODULES))
337 fw_devlink_drivers_done();
338
339 /*
340 * Trigger deferred probe again, this time we won't defer anything
341 * that is optional
342 */
343 driver_deferred_probe_trigger();
344 flush_work(&deferred_probe_work);
345
346 if (driver_deferred_probe_timeout > 0) {
347 schedule_delayed_work(&deferred_probe_timeout_work,
348 driver_deferred_probe_timeout * HZ);
349 }
350 return 0;
351}
352late_initcall(deferred_probe_initcall);
353
354static void __exit deferred_probe_exit(void)
355{
356 debugfs_remove_recursive(debugfs_lookup("devices_deferred", NULL));
357}
358__exitcall(deferred_probe_exit);
359
360/**
361 * device_is_bound() - Check if device is bound to a driver
362 * @dev: device to check
363 *
364 * Returns true if passed device has already finished probing successfully
365 * against a driver.
366 *
367 * This function must be called with the device lock held.
368 */
369bool device_is_bound(struct device *dev)
370{
371 return dev->p && klist_node_attached(&dev->p->knode_driver);
372}
373
374static void driver_bound(struct device *dev)
375{
376 if (device_is_bound(dev)) {
377 pr_warn("%s: device %s already bound\n",
378 __func__, kobject_name(&dev->kobj));
379 return;
380 }
381
382 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
383 __func__, dev_name(dev));
384
385 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
386 device_links_driver_bound(dev);
387
388 device_pm_check_callbacks(dev);
389
390 /*
391 * Make sure the device is no longer in one of the deferred lists and
392 * kick off retrying all pending devices
393 */
394 driver_deferred_probe_del(dev);
395 driver_deferred_probe_trigger();
396
397 if (dev->bus)
398 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
399 BUS_NOTIFY_BOUND_DRIVER, dev);
400
401 kobject_uevent(&dev->kobj, KOBJ_BIND);
402}
403
404static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
405 const char *buf, size_t count)
406{
407 device_lock(dev);
408 dev->driver->coredump(dev);
409 device_unlock(dev);
410
411 return count;
412}
413static DEVICE_ATTR_WO(coredump);
414
415static int driver_sysfs_add(struct device *dev)
416{
417 int ret;
418
419 if (dev->bus)
420 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
421 BUS_NOTIFY_BIND_DRIVER, dev);
422
423 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
424 kobject_name(&dev->kobj));
425 if (ret)
426 goto fail;
427
428 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
429 "driver");
430 if (ret)
431 goto rm_dev;
432
433 if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
434 return 0;
435
436 ret = device_create_file(dev, &dev_attr_coredump);
437 if (!ret)
438 return 0;
439
440 sysfs_remove_link(&dev->kobj, "driver");
441
442rm_dev:
443 sysfs_remove_link(&dev->driver->p->kobj,
444 kobject_name(&dev->kobj));
445
446fail:
447 return ret;
448}
449
450static void driver_sysfs_remove(struct device *dev)
451{
452 struct device_driver *drv = dev->driver;
453
454 if (drv) {
455 if (drv->coredump)
456 device_remove_file(dev, &dev_attr_coredump);
457 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
458 sysfs_remove_link(&dev->kobj, "driver");
459 }
460}
461
462/**
463 * device_bind_driver - bind a driver to one device.
464 * @dev: device.
465 *
466 * Allow manual attachment of a driver to a device.
467 * Caller must have already set @dev->driver.
468 *
469 * Note that this does not modify the bus reference count.
470 * Please verify that is accounted for before calling this.
471 * (It is ok to call with no other effort from a driver's probe() method.)
472 *
473 * This function must be called with the device lock held.
474 *
475 * Callers should prefer to use device_driver_attach() instead.
476 */
477int device_bind_driver(struct device *dev)
478{
479 int ret;
480
481 ret = driver_sysfs_add(dev);
482 if (!ret) {
483 device_links_force_bind(dev);
484 driver_bound(dev);
485 }
486 else if (dev->bus)
487 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
488 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
489 return ret;
490}
491EXPORT_SYMBOL_GPL(device_bind_driver);
492
493static atomic_t probe_count = ATOMIC_INIT(0);
494static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
495
496static ssize_t state_synced_show(struct device *dev,
497 struct device_attribute *attr, char *buf)
498{
499 bool val;
500
501 device_lock(dev);
502 val = dev->state_synced;
503 device_unlock(dev);
504
505 return sysfs_emit(buf, "%u\n", val);
506}
507static DEVICE_ATTR_RO(state_synced);
508
509
510static int call_driver_probe(struct device *dev, struct device_driver *drv)
511{
512 int ret = 0;
513
514 if (dev->bus->probe)
515 ret = dev->bus->probe(dev);
516 else if (drv->probe)
517 ret = drv->probe(dev);
518
519 switch (ret) {
520 case 0:
521 break;
522 case -EPROBE_DEFER:
523 /* Driver requested deferred probing */
524 dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
525 break;
526 case -ENODEV:
527 case -ENXIO:
528 pr_debug("%s: probe of %s rejects match %d\n",
529 drv->name, dev_name(dev), ret);
530 break;
531 default:
532 /* driver matched but the probe failed */
533 pr_warn("%s: probe of %s failed with error %d\n",
534 drv->name, dev_name(dev), ret);
535 break;
536 }
537
538 return ret;
539}
540
541static int really_probe(struct device *dev, struct device_driver *drv)
542{
543 bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
544 !drv->suppress_bind_attrs;
545 int ret;
546
547 if (defer_all_probes) {
548 /*
549 * Value of defer_all_probes can be set only by
550 * device_block_probing() which, in turn, will call
551 * wait_for_device_probe() right after that to avoid any races.
552 */
553 dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
554 return -EPROBE_DEFER;
555 }
556
557 ret = device_links_check_suppliers(dev);
558 if (ret)
559 return ret;
560
561 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
562 drv->bus->name, __func__, drv->name, dev_name(dev));
563 if (!list_empty(&dev->devres_head)) {
564 dev_crit(dev, "Resources present before probing\n");
565 ret = -EBUSY;
566 goto done;
567 }
568
569re_probe:
570 dev->driver = drv;
571
572 /* If using pinctrl, bind pins now before probing */
573 ret = pinctrl_bind_pins(dev);
574 if (ret)
575 goto pinctrl_bind_failed;
576
577 if (dev->bus->dma_configure) {
578 ret = dev->bus->dma_configure(dev);
579 if (ret)
580 goto probe_failed;
581 }
582
583 ret = driver_sysfs_add(dev);
584 if (ret) {
585 pr_err("%s: driver_sysfs_add(%s) failed\n",
586 __func__, dev_name(dev));
587 goto probe_failed;
588 }
589
590 if (dev->pm_domain && dev->pm_domain->activate) {
591 ret = dev->pm_domain->activate(dev);
592 if (ret)
593 goto probe_failed;
594 }
595
596 ret = call_driver_probe(dev, drv);
597 if (ret) {
598 /*
599 * Return probe errors as positive values so that the callers
600 * can distinguish them from other errors.
601 */
602 ret = -ret;
603 goto probe_failed;
604 }
605
606 ret = device_add_groups(dev, drv->dev_groups);
607 if (ret) {
608 dev_err(dev, "device_add_groups() failed\n");
609 goto dev_groups_failed;
610 }
611
612 if (dev_has_sync_state(dev)) {
613 ret = device_create_file(dev, &dev_attr_state_synced);
614 if (ret) {
615 dev_err(dev, "state_synced sysfs add failed\n");
616 goto dev_sysfs_state_synced_failed;
617 }
618 }
619
620 if (test_remove) {
621 test_remove = false;
622
623 device_remove_file(dev, &dev_attr_state_synced);
624 device_remove_groups(dev, drv->dev_groups);
625
626 if (dev->bus->remove)
627 dev->bus->remove(dev);
628 else if (drv->remove)
629 drv->remove(dev);
630
631 devres_release_all(dev);
632 driver_sysfs_remove(dev);
633 dev->driver = NULL;
634 dev_set_drvdata(dev, NULL);
635 if (dev->pm_domain && dev->pm_domain->dismiss)
636 dev->pm_domain->dismiss(dev);
637 pm_runtime_reinit(dev);
638
639 goto re_probe;
640 }
641
642 pinctrl_init_done(dev);
643
644 if (dev->pm_domain && dev->pm_domain->sync)
645 dev->pm_domain->sync(dev);
646
647 driver_bound(dev);
648 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
649 drv->bus->name, __func__, dev_name(dev), drv->name);
650 goto done;
651
652dev_sysfs_state_synced_failed:
653 device_remove_groups(dev, drv->dev_groups);
654dev_groups_failed:
655 if (dev->bus->remove)
656 dev->bus->remove(dev);
657 else if (drv->remove)
658 drv->remove(dev);
659probe_failed:
660 if (dev->bus)
661 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
662 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
663pinctrl_bind_failed:
664 device_links_no_driver(dev);
665 devres_release_all(dev);
666 arch_teardown_dma_ops(dev);
667 kfree(dev->dma_range_map);
668 dev->dma_range_map = NULL;
669 driver_sysfs_remove(dev);
670 dev->driver = NULL;
671 dev_set_drvdata(dev, NULL);
672 if (dev->pm_domain && dev->pm_domain->dismiss)
673 dev->pm_domain->dismiss(dev);
674 pm_runtime_reinit(dev);
675 dev_pm_set_driver_flags(dev, 0);
676done:
677 return ret;
678}
679
680/*
681 * For initcall_debug, show the driver probe time.
682 */
683static int really_probe_debug(struct device *dev, struct device_driver *drv)
684{
685 ktime_t calltime, rettime;
686 int ret;
687
688 calltime = ktime_get();
689 ret = really_probe(dev, drv);
690 rettime = ktime_get();
691 pr_debug("probe of %s returned %d after %lld usecs\n",
692 dev_name(dev), ret, ktime_us_delta(rettime, calltime));
693 return ret;
694}
695
696/**
697 * driver_probe_done
698 * Determine if the probe sequence is finished or not.
699 *
700 * Should somehow figure out how to use a semaphore, not an atomic variable...
701 */
702int driver_probe_done(void)
703{
704 int local_probe_count = atomic_read(&probe_count);
705
706 pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
707 if (local_probe_count)
708 return -EBUSY;
709 return 0;
710}
711
712/**
713 * wait_for_device_probe
714 * Wait for device probing to be completed.
715 */
716void wait_for_device_probe(void)
717{
718 /* wait for probe timeout */
719 wait_event(probe_timeout_waitqueue, !driver_deferred_probe_timeout);
720
721 /* wait for the deferred probe workqueue to finish */
722 flush_work(&deferred_probe_work);
723
724 /* wait for the known devices to complete their probing */
725 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
726 async_synchronize_full();
727}
728EXPORT_SYMBOL_GPL(wait_for_device_probe);
729
730static int __driver_probe_device(struct device_driver *drv, struct device *dev)
731{
732 int ret = 0;
733
734 if (dev->p->dead || !device_is_registered(dev))
735 return -ENODEV;
736 if (dev->driver)
737 return -EBUSY;
738
739 dev->can_match = true;
740 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
741 drv->bus->name, __func__, dev_name(dev), drv->name);
742
743 pm_runtime_get_suppliers(dev);
744 if (dev->parent)
745 pm_runtime_get_sync(dev->parent);
746
747 pm_runtime_barrier(dev);
748 if (initcall_debug)
749 ret = really_probe_debug(dev, drv);
750 else
751 ret = really_probe(dev, drv);
752 pm_request_idle(dev);
753
754 if (dev->parent)
755 pm_runtime_put(dev->parent);
756
757 pm_runtime_put_suppliers(dev);
758 return ret;
759}
760
761/**
762 * driver_probe_device - attempt to bind device & driver together
763 * @drv: driver to bind a device to
764 * @dev: device to try to bind to the driver
765 *
766 * This function returns -ENODEV if the device is not registered, -EBUSY if it
767 * already has a driver, 0 if the device is bound successfully and a positive
768 * (inverted) error code for failures from the ->probe method.
769 *
770 * This function must be called with @dev lock held. When called for a
771 * USB interface, @dev->parent lock must be held as well.
772 *
773 * If the device has a parent, runtime-resume the parent before driver probing.
774 */
775static int driver_probe_device(struct device_driver *drv, struct device *dev)
776{
777 int trigger_count = atomic_read(&deferred_trigger_count);
778 int ret;
779
780 atomic_inc(&probe_count);
781 ret = __driver_probe_device(drv, dev);
782 if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
783 driver_deferred_probe_add(dev);
784
785 /*
786 * Did a trigger occur while probing? Need to re-trigger if yes
787 */
788 if (trigger_count != atomic_read(&deferred_trigger_count) &&
789 !defer_all_probes)
790 driver_deferred_probe_trigger();
791 }
792 atomic_dec(&probe_count);
793 wake_up_all(&probe_waitqueue);
794 return ret;
795}
796
797static inline bool cmdline_requested_async_probing(const char *drv_name)
798{
799 return parse_option_str(async_probe_drv_names, drv_name);
800}
801
802/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
803static int __init save_async_options(char *buf)
804{
805 if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
806 pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
807
808 strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
809 return 0;
810}
811__setup("driver_async_probe=", save_async_options);
812
813bool driver_allows_async_probing(struct device_driver *drv)
814{
815 switch (drv->probe_type) {
816 case PROBE_PREFER_ASYNCHRONOUS:
817 return true;
818
819 case PROBE_FORCE_SYNCHRONOUS:
820 return false;
821
822 default:
823 if (cmdline_requested_async_probing(drv->name))
824 return true;
825
826 if (module_requested_async_probing(drv->owner))
827 return true;
828
829 return false;
830 }
831}
832
833struct device_attach_data {
834 struct device *dev;
835
836 /*
837 * Indicates whether we are are considering asynchronous probing or
838 * not. Only initial binding after device or driver registration
839 * (including deferral processing) may be done asynchronously, the
840 * rest is always synchronous, as we expect it is being done by
841 * request from userspace.
842 */
843 bool check_async;
844
845 /*
846 * Indicates if we are binding synchronous or asynchronous drivers.
847 * When asynchronous probing is enabled we'll execute 2 passes
848 * over drivers: first pass doing synchronous probing and second
849 * doing asynchronous probing (if synchronous did not succeed -
850 * most likely because there was no driver requiring synchronous
851 * probing - and we found asynchronous driver during first pass).
852 * The 2 passes are done because we can't shoot asynchronous
853 * probe for given device and driver from bus_for_each_drv() since
854 * driver pointer is not guaranteed to stay valid once
855 * bus_for_each_drv() iterates to the next driver on the bus.
856 */
857 bool want_async;
858
859 /*
860 * We'll set have_async to 'true' if, while scanning for matching
861 * driver, we'll encounter one that requests asynchronous probing.
862 */
863 bool have_async;
864};
865
866static int __device_attach_driver(struct device_driver *drv, void *_data)
867{
868 struct device_attach_data *data = _data;
869 struct device *dev = data->dev;
870 bool async_allowed;
871 int ret;
872
873 ret = driver_match_device(drv, dev);
874 if (ret == 0) {
875 /* no match */
876 return 0;
877 } else if (ret == -EPROBE_DEFER) {
878 dev_dbg(dev, "Device match requests probe deferral\n");
879 dev->can_match = true;
880 driver_deferred_probe_add(dev);
881 } else if (ret < 0) {
882 dev_dbg(dev, "Bus failed to match device: %d\n", ret);
883 return ret;
884 } /* ret > 0 means positive match */
885
886 async_allowed = driver_allows_async_probing(drv);
887
888 if (async_allowed)
889 data->have_async = true;
890
891 if (data->check_async && async_allowed != data->want_async)
892 return 0;
893
894 /*
895 * Ignore errors returned by ->probe so that the next driver can try
896 * its luck.
897 */
898 ret = driver_probe_device(drv, dev);
899 if (ret < 0)
900 return ret;
901 return ret == 0;
902}
903
904static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
905{
906 struct device *dev = _dev;
907 struct device_attach_data data = {
908 .dev = dev,
909 .check_async = true,
910 .want_async = true,
911 };
912
913 device_lock(dev);
914
915 /*
916 * Check if device has already been removed or claimed. This may
917 * happen with driver loading, device discovery/registration,
918 * and deferred probe processing happens all at once with
919 * multiple threads.
920 */
921 if (dev->p->dead || dev->driver)
922 goto out_unlock;
923
924 if (dev->parent)
925 pm_runtime_get_sync(dev->parent);
926
927 bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
928 dev_dbg(dev, "async probe completed\n");
929
930 pm_request_idle(dev);
931
932 if (dev->parent)
933 pm_runtime_put(dev->parent);
934out_unlock:
935 device_unlock(dev);
936
937 put_device(dev);
938}
939
940static int __device_attach(struct device *dev, bool allow_async)
941{
942 int ret = 0;
943
944 device_lock(dev);
945 if (dev->p->dead) {
946 goto out_unlock;
947 } else if (dev->driver) {
948 if (device_is_bound(dev)) {
949 ret = 1;
950 goto out_unlock;
951 }
952 ret = device_bind_driver(dev);
953 if (ret == 0)
954 ret = 1;
955 else {
956 dev->driver = NULL;
957 ret = 0;
958 }
959 } else {
960 struct device_attach_data data = {
961 .dev = dev,
962 .check_async = allow_async,
963 .want_async = false,
964 };
965
966 if (dev->parent)
967 pm_runtime_get_sync(dev->parent);
968
969 ret = bus_for_each_drv(dev->bus, NULL, &data,
970 __device_attach_driver);
971 if (!ret && allow_async && data.have_async) {
972 /*
973 * If we could not find appropriate driver
974 * synchronously and we are allowed to do
975 * async probes and there are drivers that
976 * want to probe asynchronously, we'll
977 * try them.
978 */
979 dev_dbg(dev, "scheduling asynchronous probe\n");
980 get_device(dev);
981 async_schedule_dev(__device_attach_async_helper, dev);
982 } else {
983 pm_request_idle(dev);
984 }
985
986 if (dev->parent)
987 pm_runtime_put(dev->parent);
988 }
989out_unlock:
990 device_unlock(dev);
991 return ret;
992}
993
994/**
995 * device_attach - try to attach device to a driver.
996 * @dev: device.
997 *
998 * Walk the list of drivers that the bus has and call
999 * driver_probe_device() for each pair. If a compatible
1000 * pair is found, break out and return.
1001 *
1002 * Returns 1 if the device was bound to a driver;
1003 * 0 if no matching driver was found;
1004 * -ENODEV if the device is not registered.
1005 *
1006 * When called for a USB interface, @dev->parent lock must be held.
1007 */
1008int device_attach(struct device *dev)
1009{
1010 return __device_attach(dev, false);
1011}
1012EXPORT_SYMBOL_GPL(device_attach);
1013
1014void device_initial_probe(struct device *dev)
1015{
1016 __device_attach(dev, true);
1017}
1018
1019/*
1020 * __device_driver_lock - acquire locks needed to manipulate dev->drv
1021 * @dev: Device we will update driver info for
1022 * @parent: Parent device. Needed if the bus requires parent lock
1023 *
1024 * This function will take the required locks for manipulating dev->drv.
1025 * Normally this will just be the @dev lock, but when called for a USB
1026 * interface, @parent lock will be held as well.
1027 */
1028static void __device_driver_lock(struct device *dev, struct device *parent)
1029{
1030 if (parent && dev->bus->need_parent_lock)
1031 device_lock(parent);
1032 device_lock(dev);
1033}
1034
1035/*
1036 * __device_driver_unlock - release locks needed to manipulate dev->drv
1037 * @dev: Device we will update driver info for
1038 * @parent: Parent device. Needed if the bus requires parent lock
1039 *
1040 * This function will release the required locks for manipulating dev->drv.
1041 * Normally this will just be the the @dev lock, but when called for a
1042 * USB interface, @parent lock will be released as well.
1043 */
1044static void __device_driver_unlock(struct device *dev, struct device *parent)
1045{
1046 device_unlock(dev);
1047 if (parent && dev->bus->need_parent_lock)
1048 device_unlock(parent);
1049}
1050
1051/**
1052 * device_driver_attach - attach a specific driver to a specific device
1053 * @drv: Driver to attach
1054 * @dev: Device to attach it to
1055 *
1056 * Manually attach driver to a device. Will acquire both @dev lock and
1057 * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
1058 */
1059int device_driver_attach(struct device_driver *drv, struct device *dev)
1060{
1061 int ret;
1062
1063 __device_driver_lock(dev, dev->parent);
1064 ret = __driver_probe_device(drv, dev);
1065 __device_driver_unlock(dev, dev->parent);
1066
1067 /* also return probe errors as normal negative errnos */
1068 if (ret > 0)
1069 ret = -ret;
1070 if (ret == -EPROBE_DEFER)
1071 return -EAGAIN;
1072 return ret;
1073}
1074EXPORT_SYMBOL_GPL(device_driver_attach);
1075
1076static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1077{
1078 struct device *dev = _dev;
1079 struct device_driver *drv;
1080 int ret;
1081
1082 __device_driver_lock(dev, dev->parent);
1083 drv = dev->p->async_driver;
1084 ret = driver_probe_device(drv, dev);
1085 __device_driver_unlock(dev, dev->parent);
1086
1087 dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1088
1089 put_device(dev);
1090}
1091
1092static int __driver_attach(struct device *dev, void *data)
1093{
1094 struct device_driver *drv = data;
1095 int ret;
1096
1097 /*
1098 * Lock device and try to bind to it. We drop the error
1099 * here and always return 0, because we need to keep trying
1100 * to bind to devices and some drivers will return an error
1101 * simply if it didn't support the device.
1102 *
1103 * driver_probe_device() will spit a warning if there
1104 * is an error.
1105 */
1106
1107 ret = driver_match_device(drv, dev);
1108 if (ret == 0) {
1109 /* no match */
1110 return 0;
1111 } else if (ret == -EPROBE_DEFER) {
1112 dev_dbg(dev, "Device match requests probe deferral\n");
1113 dev->can_match = true;
1114 driver_deferred_probe_add(dev);
1115 } else if (ret < 0) {
1116 dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1117 return ret;
1118 } /* ret > 0 means positive match */
1119
1120 if (driver_allows_async_probing(drv)) {
1121 /*
1122 * Instead of probing the device synchronously we will
1123 * probe it asynchronously to allow for more parallelism.
1124 *
1125 * We only take the device lock here in order to guarantee
1126 * that the dev->driver and async_driver fields are protected
1127 */
1128 dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1129 device_lock(dev);
1130 if (!dev->driver) {
1131 get_device(dev);
1132 dev->p->async_driver = drv;
1133 async_schedule_dev(__driver_attach_async_helper, dev);
1134 }
1135 device_unlock(dev);
1136 return 0;
1137 }
1138
1139 __device_driver_lock(dev, dev->parent);
1140 driver_probe_device(drv, dev);
1141 __device_driver_unlock(dev, dev->parent);
1142
1143 return 0;
1144}
1145
1146/**
1147 * driver_attach - try to bind driver to devices.
1148 * @drv: driver.
1149 *
1150 * Walk the list of devices that the bus has on it and try to
1151 * match the driver with each one. If driver_probe_device()
1152 * returns 0 and the @dev->driver is set, we've found a
1153 * compatible pair.
1154 */
1155int driver_attach(struct device_driver *drv)
1156{
1157 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
1158}
1159EXPORT_SYMBOL_GPL(driver_attach);
1160
1161/*
1162 * __device_release_driver() must be called with @dev lock held.
1163 * When called for a USB interface, @dev->parent lock must be held as well.
1164 */
1165static void __device_release_driver(struct device *dev, struct device *parent)
1166{
1167 struct device_driver *drv;
1168
1169 drv = dev->driver;
1170 if (drv) {
1171 pm_runtime_get_sync(dev);
1172
1173 while (device_links_busy(dev)) {
1174 __device_driver_unlock(dev, parent);
1175
1176 device_links_unbind_consumers(dev);
1177
1178 __device_driver_lock(dev, parent);
1179 /*
1180 * A concurrent invocation of the same function might
1181 * have released the driver successfully while this one
1182 * was waiting, so check for that.
1183 */
1184 if (dev->driver != drv) {
1185 pm_runtime_put(dev);
1186 return;
1187 }
1188 }
1189
1190 driver_sysfs_remove(dev);
1191
1192 if (dev->bus)
1193 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1194 BUS_NOTIFY_UNBIND_DRIVER,
1195 dev);
1196
1197 pm_runtime_put_sync(dev);
1198
1199 device_remove_file(dev, &dev_attr_state_synced);
1200 device_remove_groups(dev, drv->dev_groups);
1201
1202 if (dev->bus && dev->bus->remove)
1203 dev->bus->remove(dev);
1204 else if (drv->remove)
1205 drv->remove(dev);
1206
1207 device_links_driver_cleanup(dev);
1208
1209 devres_release_all(dev);
1210 arch_teardown_dma_ops(dev);
1211 dev->driver = NULL;
1212 dev_set_drvdata(dev, NULL);
1213 if (dev->pm_domain && dev->pm_domain->dismiss)
1214 dev->pm_domain->dismiss(dev);
1215 pm_runtime_reinit(dev);
1216 dev_pm_set_driver_flags(dev, 0);
1217
1218 klist_remove(&dev->p->knode_driver);
1219 device_pm_check_callbacks(dev);
1220 if (dev->bus)
1221 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1222 BUS_NOTIFY_UNBOUND_DRIVER,
1223 dev);
1224
1225 kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1226 }
1227}
1228
1229void device_release_driver_internal(struct device *dev,
1230 struct device_driver *drv,
1231 struct device *parent)
1232{
1233 __device_driver_lock(dev, parent);
1234
1235 if (!drv || drv == dev->driver)
1236 __device_release_driver(dev, parent);
1237
1238 __device_driver_unlock(dev, parent);
1239}
1240
1241/**
1242 * device_release_driver - manually detach device from driver.
1243 * @dev: device.
1244 *
1245 * Manually detach device from driver.
1246 * When called for a USB interface, @dev->parent lock must be held.
1247 *
1248 * If this function is to be called with @dev->parent lock held, ensure that
1249 * the device's consumers are unbound in advance or that their locks can be
1250 * acquired under the @dev->parent lock.
1251 */
1252void device_release_driver(struct device *dev)
1253{
1254 /*
1255 * If anyone calls device_release_driver() recursively from
1256 * within their ->remove callback for the same device, they
1257 * will deadlock right here.
1258 */
1259 device_release_driver_internal(dev, NULL, NULL);
1260}
1261EXPORT_SYMBOL_GPL(device_release_driver);
1262
1263/**
1264 * device_driver_detach - detach driver from a specific device
1265 * @dev: device to detach driver from
1266 *
1267 * Detach driver from device. Will acquire both @dev lock and @dev->parent
1268 * lock if needed.
1269 */
1270void device_driver_detach(struct device *dev)
1271{
1272 device_release_driver_internal(dev, NULL, dev->parent);
1273}
1274
1275/**
1276 * driver_detach - detach driver from all devices it controls.
1277 * @drv: driver.
1278 */
1279void driver_detach(struct device_driver *drv)
1280{
1281 struct device_private *dev_prv;
1282 struct device *dev;
1283
1284 if (driver_allows_async_probing(drv))
1285 async_synchronize_full();
1286
1287 for (;;) {
1288 spin_lock(&drv->p->klist_devices.k_lock);
1289 if (list_empty(&drv->p->klist_devices.k_list)) {
1290 spin_unlock(&drv->p->klist_devices.k_lock);
1291 break;
1292 }
1293 dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1294 struct device_private,
1295 knode_driver.n_node);
1296 dev = dev_prv->device;
1297 get_device(dev);
1298 spin_unlock(&drv->p->klist_devices.k_lock);
1299 device_release_driver_internal(dev, drv, dev->parent);
1300 put_device(dev);
1301 }
1302}