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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
61fc4131 PZ |
2 | /* |
3 | * Reset Controller framework | |
4 | * | |
5 | * Copyright 2013 Philipp Zabel, Pengutronix | |
61fc4131 | 6 | */ |
0b52297f | 7 | #include <linux/atomic.h> |
61fc4131 PZ |
8 | #include <linux/device.h> |
9 | #include <linux/err.h> | |
10 | #include <linux/export.h> | |
11 | #include <linux/kernel.h> | |
d25e4334 | 12 | #include <linux/kref.h> |
61fc4131 PZ |
13 | #include <linux/module.h> |
14 | #include <linux/of.h> | |
15 | #include <linux/reset.h> | |
16 | #include <linux/reset-controller.h> | |
17 | #include <linux/slab.h> | |
18 | ||
c15ddec2 | 19 | static DEFINE_MUTEX(reset_list_mutex); |
61fc4131 PZ |
20 | static LIST_HEAD(reset_controller_list); |
21 | ||
6691dffa BG |
22 | static DEFINE_MUTEX(reset_lookup_mutex); |
23 | static LIST_HEAD(reset_lookup_list); | |
24 | ||
61fc4131 PZ |
25 | /** |
26 | * struct reset_control - a reset control | |
27 | * @rcdev: a pointer to the reset controller device | |
28 | * this reset control belongs to | |
c15ddec2 | 29 | * @list: list entry for the rcdev's reset controller list |
61fc4131 PZ |
30 | * @id: ID of the reset controller in the reset |
31 | * controller device | |
c15ddec2 | 32 | * @refcnt: Number of gets of this reset_control |
c84b0326 | 33 | * @acquired: Only one reset_control may be acquired for a given rcdev and id. |
0b52297f HG |
34 | * @shared: Is this a shared (1), or an exclusive (0) reset_control? |
35 | * @deassert_cnt: Number of times this reset line has been deasserted | |
7da33a37 MB |
36 | * @triggered_count: Number of times this reset line has been reset. Currently |
37 | * only used for shared resets, which means that the value | |
38 | * will be either 0 or 1. | |
61fc4131 PZ |
39 | */ |
40 | struct reset_control { | |
41 | struct reset_controller_dev *rcdev; | |
c15ddec2 | 42 | struct list_head list; |
61fc4131 | 43 | unsigned int id; |
d25e4334 | 44 | struct kref refcnt; |
c84b0326 | 45 | bool acquired; |
ee48c726 | 46 | bool shared; |
17c82e20 | 47 | bool array; |
0b52297f | 48 | atomic_t deassert_count; |
7da33a37 | 49 | atomic_t triggered_count; |
61fc4131 PZ |
50 | }; |
51 | ||
17c82e20 VG |
52 | /** |
53 | * struct reset_control_array - an array of reset controls | |
54 | * @base: reset control for compatibility with reset control API functions | |
55 | * @num_rstcs: number of reset controls | |
56 | * @rstc: array of reset controls | |
57 | */ | |
58 | struct reset_control_array { | |
59 | struct reset_control base; | |
60 | unsigned int num_rstcs; | |
61 | struct reset_control *rstc[]; | |
62 | }; | |
63 | ||
c84b0326 PZ |
64 | static const char *rcdev_name(struct reset_controller_dev *rcdev) |
65 | { | |
66 | if (rcdev->dev) | |
67 | return dev_name(rcdev->dev); | |
68 | ||
69 | if (rcdev->of_node) | |
70 | return rcdev->of_node->full_name; | |
71 | ||
72 | return NULL; | |
73 | } | |
74 | ||
61fc4131 PZ |
75 | /** |
76 | * of_reset_simple_xlate - translate reset_spec to the reset line number | |
77 | * @rcdev: a pointer to the reset controller device | |
78 | * @reset_spec: reset line specifier as found in the device tree | |
79 | * @flags: a flags pointer to fill in (optional) | |
80 | * | |
81 | * This simple translation function should be used for reset controllers | |
82 | * with 1:1 mapping, where reset lines can be indexed by number without gaps. | |
83 | */ | |
0c5b2b91 | 84 | static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, |
61fc4131 PZ |
85 | const struct of_phandle_args *reset_spec) |
86 | { | |
61fc4131 PZ |
87 | if (reset_spec->args[0] >= rcdev->nr_resets) |
88 | return -EINVAL; | |
89 | ||
90 | return reset_spec->args[0]; | |
91 | } | |
61fc4131 PZ |
92 | |
93 | /** | |
94 | * reset_controller_register - register a reset controller device | |
95 | * @rcdev: a pointer to the initialized reset controller device | |
96 | */ | |
97 | int reset_controller_register(struct reset_controller_dev *rcdev) | |
98 | { | |
99 | if (!rcdev->of_xlate) { | |
100 | rcdev->of_reset_n_cells = 1; | |
101 | rcdev->of_xlate = of_reset_simple_xlate; | |
102 | } | |
103 | ||
c15ddec2 HG |
104 | INIT_LIST_HEAD(&rcdev->reset_control_head); |
105 | ||
106 | mutex_lock(&reset_list_mutex); | |
61fc4131 | 107 | list_add(&rcdev->list, &reset_controller_list); |
c15ddec2 | 108 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
109 | |
110 | return 0; | |
111 | } | |
112 | EXPORT_SYMBOL_GPL(reset_controller_register); | |
113 | ||
114 | /** | |
115 | * reset_controller_unregister - unregister a reset controller device | |
116 | * @rcdev: a pointer to the reset controller device | |
117 | */ | |
118 | void reset_controller_unregister(struct reset_controller_dev *rcdev) | |
119 | { | |
c15ddec2 | 120 | mutex_lock(&reset_list_mutex); |
61fc4131 | 121 | list_del(&rcdev->list); |
c15ddec2 | 122 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
123 | } |
124 | EXPORT_SYMBOL_GPL(reset_controller_unregister); | |
125 | ||
8d5b5d5c MY |
126 | static void devm_reset_controller_release(struct device *dev, void *res) |
127 | { | |
128 | reset_controller_unregister(*(struct reset_controller_dev **)res); | |
129 | } | |
130 | ||
131 | /** | |
132 | * devm_reset_controller_register - resource managed reset_controller_register() | |
133 | * @dev: device that is registering this reset controller | |
134 | * @rcdev: a pointer to the initialized reset controller device | |
135 | * | |
136 | * Managed reset_controller_register(). For reset controllers registered by | |
137 | * this function, reset_controller_unregister() is automatically called on | |
138 | * driver detach. See reset_controller_register() for more information. | |
139 | */ | |
140 | int devm_reset_controller_register(struct device *dev, | |
141 | struct reset_controller_dev *rcdev) | |
142 | { | |
143 | struct reset_controller_dev **rcdevp; | |
144 | int ret; | |
145 | ||
146 | rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp), | |
147 | GFP_KERNEL); | |
148 | if (!rcdevp) | |
149 | return -ENOMEM; | |
150 | ||
151 | ret = reset_controller_register(rcdev); | |
152 | if (!ret) { | |
153 | *rcdevp = rcdev; | |
154 | devres_add(dev, rcdevp); | |
155 | } else { | |
156 | devres_free(rcdevp); | |
157 | } | |
158 | ||
159 | return ret; | |
160 | } | |
161 | EXPORT_SYMBOL_GPL(devm_reset_controller_register); | |
162 | ||
6691dffa BG |
163 | /** |
164 | * reset_controller_add_lookup - register a set of lookup entries | |
6691dffa BG |
165 | * @lookup: array of reset lookup entries |
166 | * @num_entries: number of entries in the lookup array | |
167 | */ | |
e2749bb9 | 168 | void reset_controller_add_lookup(struct reset_control_lookup *lookup, |
6691dffa BG |
169 | unsigned int num_entries) |
170 | { | |
171 | struct reset_control_lookup *entry; | |
172 | unsigned int i; | |
173 | ||
174 | mutex_lock(&reset_lookup_mutex); | |
175 | for (i = 0; i < num_entries; i++) { | |
176 | entry = &lookup[i]; | |
177 | ||
e2749bb9 BG |
178 | if (!entry->dev_id || !entry->provider) { |
179 | pr_warn("%s(): reset lookup entry badly specified, skipping\n", | |
6691dffa BG |
180 | __func__); |
181 | continue; | |
182 | } | |
183 | ||
6691dffa BG |
184 | list_add_tail(&entry->list, &reset_lookup_list); |
185 | } | |
186 | mutex_unlock(&reset_lookup_mutex); | |
187 | } | |
188 | EXPORT_SYMBOL_GPL(reset_controller_add_lookup); | |
189 | ||
17c82e20 VG |
190 | static inline struct reset_control_array * |
191 | rstc_to_array(struct reset_control *rstc) { | |
192 | return container_of(rstc, struct reset_control_array, base); | |
193 | } | |
194 | ||
195 | static int reset_control_array_reset(struct reset_control_array *resets) | |
196 | { | |
197 | int ret, i; | |
198 | ||
199 | for (i = 0; i < resets->num_rstcs; i++) { | |
200 | ret = reset_control_reset(resets->rstc[i]); | |
201 | if (ret) | |
202 | return ret; | |
203 | } | |
204 | ||
205 | return 0; | |
206 | } | |
207 | ||
208 | static int reset_control_array_assert(struct reset_control_array *resets) | |
209 | { | |
210 | int ret, i; | |
211 | ||
212 | for (i = 0; i < resets->num_rstcs; i++) { | |
213 | ret = reset_control_assert(resets->rstc[i]); | |
214 | if (ret) | |
215 | goto err; | |
216 | } | |
217 | ||
218 | return 0; | |
219 | ||
220 | err: | |
221 | while (i--) | |
222 | reset_control_deassert(resets->rstc[i]); | |
223 | return ret; | |
224 | } | |
225 | ||
226 | static int reset_control_array_deassert(struct reset_control_array *resets) | |
227 | { | |
228 | int ret, i; | |
229 | ||
230 | for (i = 0; i < resets->num_rstcs; i++) { | |
231 | ret = reset_control_deassert(resets->rstc[i]); | |
232 | if (ret) | |
233 | goto err; | |
234 | } | |
235 | ||
236 | return 0; | |
237 | ||
238 | err: | |
239 | while (i--) | |
240 | reset_control_assert(resets->rstc[i]); | |
241 | return ret; | |
242 | } | |
243 | ||
22815f18 TR |
244 | static int reset_control_array_acquire(struct reset_control_array *resets) |
245 | { | |
246 | unsigned int i; | |
247 | int err; | |
248 | ||
249 | for (i = 0; i < resets->num_rstcs; i++) { | |
250 | err = reset_control_acquire(resets->rstc[i]); | |
251 | if (err < 0) | |
252 | goto release; | |
253 | } | |
254 | ||
255 | return 0; | |
256 | ||
257 | release: | |
258 | while (i--) | |
259 | reset_control_release(resets->rstc[i]); | |
260 | ||
261 | return err; | |
262 | } | |
263 | ||
264 | static void reset_control_array_release(struct reset_control_array *resets) | |
265 | { | |
266 | unsigned int i; | |
267 | ||
268 | for (i = 0; i < resets->num_rstcs; i++) | |
269 | reset_control_release(resets->rstc[i]); | |
270 | } | |
271 | ||
17c82e20 VG |
272 | static inline bool reset_control_is_array(struct reset_control *rstc) |
273 | { | |
274 | return rstc->array; | |
275 | } | |
276 | ||
61fc4131 PZ |
277 | /** |
278 | * reset_control_reset - reset the controlled device | |
279 | * @rstc: reset controller | |
0b52297f | 280 | * |
7da33a37 MB |
281 | * On a shared reset line the actual reset pulse is only triggered once for the |
282 | * lifetime of the reset_control instance: for all but the first caller this is | |
283 | * a no-op. | |
284 | * Consumers must not use reset_control_(de)assert on shared reset lines when | |
285 | * reset_control_reset has been used. | |
bb475230 RO |
286 | * |
287 | * If rstc is NULL it is an optional reset and the function will just | |
288 | * return 0. | |
61fc4131 PZ |
289 | */ |
290 | int reset_control_reset(struct reset_control *rstc) | |
291 | { | |
7da33a37 MB |
292 | int ret; |
293 | ||
bb475230 RO |
294 | if (!rstc) |
295 | return 0; | |
296 | ||
297 | if (WARN_ON(IS_ERR(rstc))) | |
0b52297f HG |
298 | return -EINVAL; |
299 | ||
17c82e20 VG |
300 | if (reset_control_is_array(rstc)) |
301 | return reset_control_array_reset(rstc_to_array(rstc)); | |
302 | ||
7da33a37 MB |
303 | if (!rstc->rcdev->ops->reset) |
304 | return -ENOTSUPP; | |
305 | ||
306 | if (rstc->shared) { | |
307 | if (WARN_ON(atomic_read(&rstc->deassert_count) != 0)) | |
308 | return -EINVAL; | |
309 | ||
310 | if (atomic_inc_return(&rstc->triggered_count) != 1) | |
311 | return 0; | |
c84b0326 PZ |
312 | } else { |
313 | if (!rstc->acquired) | |
314 | return -EPERM; | |
7da33a37 | 315 | } |
61fc4131 | 316 | |
7da33a37 | 317 | ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); |
e5a1dade | 318 | if (rstc->shared && ret) |
7da33a37 MB |
319 | atomic_dec(&rstc->triggered_count); |
320 | ||
321 | return ret; | |
61fc4131 PZ |
322 | } |
323 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
324 | ||
325 | /** | |
326 | * reset_control_assert - asserts the reset line | |
327 | * @rstc: reset controller | |
0b52297f HG |
328 | * |
329 | * Calling this on an exclusive reset controller guarantees that the reset | |
330 | * will be asserted. When called on a shared reset controller the line may | |
331 | * still be deasserted, as long as other users keep it so. | |
332 | * | |
333 | * For shared reset controls a driver cannot expect the hw's registers and | |
334 | * internal state to be reset, but must be prepared for this to happen. | |
7da33a37 MB |
335 | * Consumers must not use reset_control_reset on shared reset lines when |
336 | * reset_control_(de)assert has been used. | |
bb475230 RO |
337 | * return 0. |
338 | * | |
339 | * If rstc is NULL it is an optional reset and the function will just | |
340 | * return 0. | |
61fc4131 PZ |
341 | */ |
342 | int reset_control_assert(struct reset_control *rstc) | |
343 | { | |
bb475230 RO |
344 | if (!rstc) |
345 | return 0; | |
346 | ||
347 | if (WARN_ON(IS_ERR(rstc))) | |
a3774e14 PZ |
348 | return -EINVAL; |
349 | ||
17c82e20 VG |
350 | if (reset_control_is_array(rstc)) |
351 | return reset_control_array_assert(rstc_to_array(rstc)); | |
352 | ||
0b52297f | 353 | if (rstc->shared) { |
7da33a37 MB |
354 | if (WARN_ON(atomic_read(&rstc->triggered_count) != 0)) |
355 | return -EINVAL; | |
356 | ||
0b52297f HG |
357 | if (WARN_ON(atomic_read(&rstc->deassert_count) == 0)) |
358 | return -EINVAL; | |
359 | ||
360 | if (atomic_dec_return(&rstc->deassert_count) != 0) | |
361 | return 0; | |
21240eb9 PZ |
362 | |
363 | /* | |
364 | * Shared reset controls allow the reset line to be in any state | |
365 | * after this call, so doing nothing is a valid option. | |
366 | */ | |
367 | if (!rstc->rcdev->ops->assert) | |
368 | return 0; | |
369 | } else { | |
370 | /* | |
371 | * If the reset controller does not implement .assert(), there | |
372 | * is no way to guarantee that the reset line is asserted after | |
373 | * this call. | |
374 | */ | |
375 | if (!rstc->rcdev->ops->assert) | |
376 | return -ENOTSUPP; | |
c84b0326 PZ |
377 | |
378 | if (!rstc->acquired) { | |
379 | WARN(1, "reset %s (ID: %u) is not acquired\n", | |
380 | rcdev_name(rstc->rcdev), rstc->id); | |
381 | return -EPERM; | |
382 | } | |
0b52297f HG |
383 | } |
384 | ||
385 | return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); | |
61fc4131 PZ |
386 | } |
387 | EXPORT_SYMBOL_GPL(reset_control_assert); | |
388 | ||
389 | /** | |
390 | * reset_control_deassert - deasserts the reset line | |
391 | * @rstc: reset controller | |
0b52297f HG |
392 | * |
393 | * After calling this function, the reset is guaranteed to be deasserted. | |
7da33a37 MB |
394 | * Consumers must not use reset_control_reset on shared reset lines when |
395 | * reset_control_(de)assert has been used. | |
bb475230 RO |
396 | * return 0. |
397 | * | |
398 | * If rstc is NULL it is an optional reset and the function will just | |
399 | * return 0. | |
61fc4131 PZ |
400 | */ |
401 | int reset_control_deassert(struct reset_control *rstc) | |
402 | { | |
bb475230 RO |
403 | if (!rstc) |
404 | return 0; | |
405 | ||
406 | if (WARN_ON(IS_ERR(rstc))) | |
a3774e14 PZ |
407 | return -EINVAL; |
408 | ||
17c82e20 VG |
409 | if (reset_control_is_array(rstc)) |
410 | return reset_control_array_deassert(rstc_to_array(rstc)); | |
411 | ||
0b52297f | 412 | if (rstc->shared) { |
7da33a37 MB |
413 | if (WARN_ON(atomic_read(&rstc->triggered_count) != 0)) |
414 | return -EINVAL; | |
415 | ||
0b52297f HG |
416 | if (atomic_inc_return(&rstc->deassert_count) != 1) |
417 | return 0; | |
c84b0326 PZ |
418 | } else { |
419 | if (!rstc->acquired) { | |
420 | WARN(1, "reset %s (ID: %u) is not acquired\n", | |
421 | rcdev_name(rstc->rcdev), rstc->id); | |
422 | return -EPERM; | |
423 | } | |
0b52297f HG |
424 | } |
425 | ||
21240eb9 PZ |
426 | /* |
427 | * If the reset controller does not implement .deassert(), we assume | |
428 | * that it handles self-deasserting reset lines via .reset(). In that | |
429 | * case, the reset lines are deasserted by default. If that is not the | |
430 | * case, the reset controller driver should implement .deassert() and | |
431 | * return -ENOTSUPP. | |
432 | */ | |
433 | if (!rstc->rcdev->ops->deassert) | |
434 | return 0; | |
435 | ||
0b52297f | 436 | return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); |
61fc4131 PZ |
437 | } |
438 | EXPORT_SYMBOL_GPL(reset_control_deassert); | |
439 | ||
729de41b DN |
440 | /** |
441 | * reset_control_status - returns a negative errno if not supported, a | |
442 | * positive value if the reset line is asserted, or zero if the reset | |
bb475230 | 443 | * line is not asserted or if the desc is NULL (optional reset). |
729de41b DN |
444 | * @rstc: reset controller |
445 | */ | |
446 | int reset_control_status(struct reset_control *rstc) | |
447 | { | |
bb475230 RO |
448 | if (!rstc) |
449 | return 0; | |
450 | ||
17c82e20 | 451 | if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc)) |
a3774e14 PZ |
452 | return -EINVAL; |
453 | ||
729de41b DN |
454 | if (rstc->rcdev->ops->status) |
455 | return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); | |
456 | ||
39b4da71 | 457 | return -ENOTSUPP; |
729de41b DN |
458 | } |
459 | EXPORT_SYMBOL_GPL(reset_control_status); | |
460 | ||
c84b0326 PZ |
461 | /** |
462 | * reset_control_acquire() - acquires a reset control for exclusive use | |
463 | * @rstc: reset control | |
464 | * | |
465 | * This is used to explicitly acquire a reset control for exclusive use. Note | |
466 | * that exclusive resets are requested as acquired by default. In order for a | |
467 | * second consumer to be able to control the reset, the first consumer has to | |
468 | * release it first. Typically the easiest way to achieve this is to call the | |
469 | * reset_control_get_exclusive_released() to obtain an instance of the reset | |
470 | * control. Such reset controls are not acquired by default. | |
471 | * | |
472 | * Consumers implementing shared access to an exclusive reset need to follow | |
473 | * a specific protocol in order to work together. Before consumers can change | |
474 | * a reset they must acquire exclusive access using reset_control_acquire(). | |
475 | * After they are done operating the reset, they must release exclusive access | |
476 | * with a call to reset_control_release(). Consumers are not granted exclusive | |
477 | * access to the reset as long as another consumer hasn't released a reset. | |
478 | * | |
479 | * See also: reset_control_release() | |
480 | */ | |
481 | int reset_control_acquire(struct reset_control *rstc) | |
482 | { | |
483 | struct reset_control *rc; | |
484 | ||
485 | if (!rstc) | |
486 | return 0; | |
487 | ||
488 | if (WARN_ON(IS_ERR(rstc))) | |
489 | return -EINVAL; | |
490 | ||
22815f18 TR |
491 | if (reset_control_is_array(rstc)) |
492 | return reset_control_array_acquire(rstc_to_array(rstc)); | |
493 | ||
c84b0326 PZ |
494 | mutex_lock(&reset_list_mutex); |
495 | ||
496 | if (rstc->acquired) { | |
497 | mutex_unlock(&reset_list_mutex); | |
498 | return 0; | |
499 | } | |
500 | ||
501 | list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) { | |
502 | if (rstc != rc && rstc->id == rc->id) { | |
503 | if (rc->acquired) { | |
504 | mutex_unlock(&reset_list_mutex); | |
505 | return -EBUSY; | |
506 | } | |
507 | } | |
508 | } | |
509 | ||
510 | rstc->acquired = true; | |
511 | ||
512 | mutex_unlock(&reset_list_mutex); | |
513 | return 0; | |
514 | } | |
515 | EXPORT_SYMBOL_GPL(reset_control_acquire); | |
516 | ||
517 | /** | |
518 | * reset_control_release() - releases exclusive access to a reset control | |
519 | * @rstc: reset control | |
520 | * | |
521 | * Releases exclusive access right to a reset control previously obtained by a | |
522 | * call to reset_control_acquire(). Until a consumer calls this function, no | |
523 | * other consumers will be granted exclusive access. | |
524 | * | |
525 | * See also: reset_control_acquire() | |
526 | */ | |
527 | void reset_control_release(struct reset_control *rstc) | |
528 | { | |
529 | if (!rstc || WARN_ON(IS_ERR(rstc))) | |
530 | return; | |
531 | ||
22815f18 TR |
532 | if (reset_control_is_array(rstc)) |
533 | reset_control_array_release(rstc_to_array(rstc)); | |
534 | else | |
535 | rstc->acquired = false; | |
c84b0326 PZ |
536 | } |
537 | EXPORT_SYMBOL_GPL(reset_control_release); | |
538 | ||
62e24c57 | 539 | static struct reset_control *__reset_control_get_internal( |
c15ddec2 | 540 | struct reset_controller_dev *rcdev, |
c84b0326 | 541 | unsigned int index, bool shared, bool acquired) |
c15ddec2 HG |
542 | { |
543 | struct reset_control *rstc; | |
544 | ||
545 | lockdep_assert_held(&reset_list_mutex); | |
546 | ||
547 | list_for_each_entry(rstc, &rcdev->reset_control_head, list) { | |
548 | if (rstc->id == index) { | |
c84b0326 PZ |
549 | /* |
550 | * Allow creating a secondary exclusive reset_control | |
551 | * that is initially not acquired for an already | |
552 | * controlled reset line. | |
553 | */ | |
554 | if (!rstc->shared && !shared && !acquired) | |
555 | break; | |
556 | ||
0b52297f HG |
557 | if (WARN_ON(!rstc->shared || !shared)) |
558 | return ERR_PTR(-EBUSY); | |
559 | ||
d25e4334 | 560 | kref_get(&rstc->refcnt); |
c15ddec2 HG |
561 | return rstc; |
562 | } | |
563 | } | |
564 | ||
565 | rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); | |
566 | if (!rstc) | |
567 | return ERR_PTR(-ENOMEM); | |
568 | ||
569 | try_module_get(rcdev->owner); | |
570 | ||
571 | rstc->rcdev = rcdev; | |
572 | list_add(&rstc->list, &rcdev->reset_control_head); | |
573 | rstc->id = index; | |
d25e4334 | 574 | kref_init(&rstc->refcnt); |
c84b0326 | 575 | rstc->acquired = acquired; |
0b52297f | 576 | rstc->shared = shared; |
c15ddec2 HG |
577 | |
578 | return rstc; | |
579 | } | |
580 | ||
d25e4334 | 581 | static void __reset_control_release(struct kref *kref) |
c15ddec2 | 582 | { |
d25e4334 PZ |
583 | struct reset_control *rstc = container_of(kref, struct reset_control, |
584 | refcnt); | |
c15ddec2 | 585 | |
d25e4334 | 586 | lockdep_assert_held(&reset_list_mutex); |
c15ddec2 HG |
587 | |
588 | module_put(rstc->rcdev->owner); | |
589 | ||
590 | list_del(&rstc->list); | |
591 | kfree(rstc); | |
592 | } | |
593 | ||
d25e4334 PZ |
594 | static void __reset_control_put_internal(struct reset_control *rstc) |
595 | { | |
596 | lockdep_assert_held(&reset_list_mutex); | |
597 | ||
598 | kref_put(&rstc->refcnt, __reset_control_release); | |
599 | } | |
600 | ||
6c96f05c | 601 | struct reset_control *__of_reset_control_get(struct device_node *node, |
bb475230 | 602 | const char *id, int index, bool shared, |
c84b0326 | 603 | bool optional, bool acquired) |
61fc4131 | 604 | { |
d056c9b8 | 605 | struct reset_control *rstc; |
61fc4131 PZ |
606 | struct reset_controller_dev *r, *rcdev; |
607 | struct of_phandle_args args; | |
61fc4131 PZ |
608 | int rstc_id; |
609 | int ret; | |
610 | ||
6c96f05c HG |
611 | if (!node) |
612 | return ERR_PTR(-EINVAL); | |
613 | ||
614 | if (id) { | |
615 | index = of_property_match_string(node, | |
616 | "reset-names", id); | |
bb475230 RO |
617 | if (index == -EILSEQ) |
618 | return ERR_PTR(index); | |
6c96f05c | 619 | if (index < 0) |
bb475230 | 620 | return optional ? NULL : ERR_PTR(-ENOENT); |
6c96f05c HG |
621 | } |
622 | ||
fc0a5921 | 623 | ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
61fc4131 | 624 | index, &args); |
bb475230 | 625 | if (ret == -EINVAL) |
61fc4131 | 626 | return ERR_PTR(ret); |
bb475230 RO |
627 | if (ret) |
628 | return optional ? NULL : ERR_PTR(ret); | |
61fc4131 | 629 | |
c15ddec2 | 630 | mutex_lock(&reset_list_mutex); |
61fc4131 PZ |
631 | rcdev = NULL; |
632 | list_for_each_entry(r, &reset_controller_list, list) { | |
633 | if (args.np == r->of_node) { | |
634 | rcdev = r; | |
635 | break; | |
636 | } | |
637 | } | |
61fc4131 PZ |
638 | |
639 | if (!rcdev) { | |
b790c8ea GU |
640 | rstc = ERR_PTR(-EPROBE_DEFER); |
641 | goto out; | |
61fc4131 PZ |
642 | } |
643 | ||
e677774f | 644 | if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { |
b790c8ea GU |
645 | rstc = ERR_PTR(-EINVAL); |
646 | goto out; | |
e677774f MR |
647 | } |
648 | ||
61fc4131 PZ |
649 | rstc_id = rcdev->of_xlate(rcdev, &args); |
650 | if (rstc_id < 0) { | |
b790c8ea GU |
651 | rstc = ERR_PTR(rstc_id); |
652 | goto out; | |
61fc4131 PZ |
653 | } |
654 | ||
c15ddec2 | 655 | /* reset_list_mutex also protects the rcdev's reset_control list */ |
c84b0326 | 656 | rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired); |
61fc4131 | 657 | |
b790c8ea | 658 | out: |
c15ddec2 | 659 | mutex_unlock(&reset_list_mutex); |
b790c8ea | 660 | of_node_put(args.np); |
61fc4131 PZ |
661 | |
662 | return rstc; | |
663 | } | |
6c96f05c | 664 | EXPORT_SYMBOL_GPL(__of_reset_control_get); |
61fc4131 | 665 | |
e2749bb9 BG |
666 | static struct reset_controller_dev * |
667 | __reset_controller_by_name(const char *name) | |
668 | { | |
669 | struct reset_controller_dev *rcdev; | |
670 | ||
671 | lockdep_assert_held(&reset_list_mutex); | |
672 | ||
673 | list_for_each_entry(rcdev, &reset_controller_list, list) { | |
674 | if (!rcdev->dev) | |
675 | continue; | |
676 | ||
677 | if (!strcmp(name, dev_name(rcdev->dev))) | |
678 | return rcdev; | |
679 | } | |
680 | ||
681 | return NULL; | |
682 | } | |
683 | ||
6691dffa BG |
684 | static struct reset_control * |
685 | __reset_control_get_from_lookup(struct device *dev, const char *con_id, | |
c84b0326 | 686 | bool shared, bool optional, bool acquired) |
6691dffa BG |
687 | { |
688 | const struct reset_control_lookup *lookup; | |
e2749bb9 | 689 | struct reset_controller_dev *rcdev; |
6691dffa BG |
690 | const char *dev_id = dev_name(dev); |
691 | struct reset_control *rstc = NULL; | |
692 | ||
693 | if (!dev) | |
694 | return ERR_PTR(-EINVAL); | |
695 | ||
696 | mutex_lock(&reset_lookup_mutex); | |
697 | ||
698 | list_for_each_entry(lookup, &reset_lookup_list, list) { | |
699 | if (strcmp(lookup->dev_id, dev_id)) | |
700 | continue; | |
701 | ||
702 | if ((!con_id && !lookup->con_id) || | |
703 | ((con_id && lookup->con_id) && | |
704 | !strcmp(con_id, lookup->con_id))) { | |
705 | mutex_lock(&reset_list_mutex); | |
e2749bb9 BG |
706 | rcdev = __reset_controller_by_name(lookup->provider); |
707 | if (!rcdev) { | |
708 | mutex_unlock(&reset_list_mutex); | |
709 | mutex_unlock(&reset_lookup_mutex); | |
710 | /* Reset provider may not be ready yet. */ | |
711 | return ERR_PTR(-EPROBE_DEFER); | |
712 | } | |
713 | ||
714 | rstc = __reset_control_get_internal(rcdev, | |
6691dffa | 715 | lookup->index, |
c84b0326 | 716 | shared, acquired); |
6691dffa BG |
717 | mutex_unlock(&reset_list_mutex); |
718 | break; | |
719 | } | |
720 | } | |
721 | ||
722 | mutex_unlock(&reset_lookup_mutex); | |
723 | ||
724 | if (!rstc) | |
725 | return optional ? NULL : ERR_PTR(-ENOENT); | |
726 | ||
727 | return rstc; | |
728 | } | |
729 | ||
62e24c57 | 730 | struct reset_control *__reset_control_get(struct device *dev, const char *id, |
c84b0326 PZ |
731 | int index, bool shared, bool optional, |
732 | bool acquired) | |
62e24c57 | 733 | { |
c84b0326 PZ |
734 | if (WARN_ON(shared && acquired)) |
735 | return ERR_PTR(-EINVAL); | |
736 | ||
62e24c57 PZ |
737 | if (dev->of_node) |
738 | return __of_reset_control_get(dev->of_node, id, index, shared, | |
c84b0326 | 739 | optional, acquired); |
62e24c57 | 740 | |
c84b0326 PZ |
741 | return __reset_control_get_from_lookup(dev, id, shared, optional, |
742 | acquired); | |
62e24c57 PZ |
743 | } |
744 | EXPORT_SYMBOL_GPL(__reset_control_get); | |
745 | ||
17c82e20 VG |
746 | static void reset_control_array_put(struct reset_control_array *resets) |
747 | { | |
748 | int i; | |
749 | ||
750 | mutex_lock(&reset_list_mutex); | |
751 | for (i = 0; i < resets->num_rstcs; i++) | |
752 | __reset_control_put_internal(resets->rstc[i]); | |
753 | mutex_unlock(&reset_list_mutex); | |
754 | } | |
755 | ||
61fc4131 PZ |
756 | /** |
757 | * reset_control_put - free the reset controller | |
758 | * @rstc: reset controller | |
759 | */ | |
61fc4131 PZ |
760 | void reset_control_put(struct reset_control *rstc) |
761 | { | |
4891486f | 762 | if (IS_ERR_OR_NULL(rstc)) |
61fc4131 PZ |
763 | return; |
764 | ||
17c82e20 VG |
765 | if (reset_control_is_array(rstc)) { |
766 | reset_control_array_put(rstc_to_array(rstc)); | |
767 | return; | |
768 | } | |
769 | ||
c15ddec2 | 770 | mutex_lock(&reset_list_mutex); |
62e24c57 | 771 | __reset_control_put_internal(rstc); |
c15ddec2 | 772 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
773 | } |
774 | EXPORT_SYMBOL_GPL(reset_control_put); | |
775 | ||
776 | static void devm_reset_control_release(struct device *dev, void *res) | |
777 | { | |
778 | reset_control_put(*(struct reset_control **)res); | |
779 | } | |
780 | ||
6c96f05c | 781 | struct reset_control *__devm_reset_control_get(struct device *dev, |
bb475230 | 782 | const char *id, int index, bool shared, |
c84b0326 | 783 | bool optional, bool acquired) |
61fc4131 PZ |
784 | { |
785 | struct reset_control **ptr, *rstc; | |
786 | ||
787 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
788 | GFP_KERNEL); | |
789 | if (!ptr) | |
790 | return ERR_PTR(-ENOMEM); | |
791 | ||
c84b0326 | 792 | rstc = __reset_control_get(dev, id, index, shared, optional, acquired); |
61fc4131 PZ |
793 | if (!IS_ERR(rstc)) { |
794 | *ptr = rstc; | |
795 | devres_add(dev, ptr); | |
796 | } else { | |
797 | devres_free(ptr); | |
798 | } | |
799 | ||
800 | return rstc; | |
801 | } | |
6c96f05c | 802 | EXPORT_SYMBOL_GPL(__devm_reset_control_get); |
61fc4131 | 803 | |
61fc4131 PZ |
804 | /** |
805 | * device_reset - find reset controller associated with the device | |
806 | * and perform reset | |
807 | * @dev: device to be reset by the controller | |
1554bbd4 | 808 | * @optional: whether it is optional to reset the device |
61fc4131 | 809 | * |
1554bbd4 | 810 | * Convenience wrapper for __reset_control_get() and reset_control_reset(). |
61fc4131 PZ |
811 | * This is useful for the common case of devices with single, dedicated reset |
812 | * lines. | |
813 | */ | |
1554bbd4 | 814 | int __device_reset(struct device *dev, bool optional) |
61fc4131 PZ |
815 | { |
816 | struct reset_control *rstc; | |
817 | int ret; | |
818 | ||
c84b0326 | 819 | rstc = __reset_control_get(dev, NULL, 0, 0, optional, true); |
61fc4131 PZ |
820 | if (IS_ERR(rstc)) |
821 | return PTR_ERR(rstc); | |
822 | ||
823 | ret = reset_control_reset(rstc); | |
824 | ||
825 | reset_control_put(rstc); | |
826 | ||
827 | return ret; | |
828 | } | |
1554bbd4 | 829 | EXPORT_SYMBOL_GPL(__device_reset); |
17c82e20 VG |
830 | |
831 | /** | |
832 | * APIs to manage an array of reset controls. | |
833 | */ | |
834 | /** | |
835 | * of_reset_control_get_count - Count number of resets available with a device | |
836 | * | |
837 | * @node: device node that contains 'resets'. | |
838 | * | |
839 | * Returns positive reset count on success, or error number on failure and | |
840 | * on count being zero. | |
841 | */ | |
842 | static int of_reset_control_get_count(struct device_node *node) | |
843 | { | |
844 | int count; | |
845 | ||
846 | if (!node) | |
847 | return -EINVAL; | |
848 | ||
849 | count = of_count_phandle_with_args(node, "resets", "#reset-cells"); | |
850 | if (count == 0) | |
851 | count = -ENOENT; | |
852 | ||
853 | return count; | |
854 | } | |
855 | ||
856 | /** | |
857 | * of_reset_control_array_get - Get a list of reset controls using | |
858 | * device node. | |
859 | * | |
860 | * @np: device node for the device that requests the reset controls array | |
861 | * @shared: whether reset controls are shared or not | |
862 | * @optional: whether it is optional to get the reset controls | |
f31d5c24 TR |
863 | * @acquired: only one reset control may be acquired for a given controller |
864 | * and ID | |
17c82e20 VG |
865 | * |
866 | * Returns pointer to allocated reset_control_array on success or | |
867 | * error on failure | |
868 | */ | |
869 | struct reset_control * | |
f31d5c24 TR |
870 | of_reset_control_array_get(struct device_node *np, bool shared, bool optional, |
871 | bool acquired) | |
17c82e20 VG |
872 | { |
873 | struct reset_control_array *resets; | |
874 | struct reset_control *rstc; | |
875 | int num, i; | |
876 | ||
877 | num = of_reset_control_get_count(np); | |
878 | if (num < 0) | |
879 | return optional ? NULL : ERR_PTR(num); | |
880 | ||
acafe7e3 | 881 | resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL); |
17c82e20 VG |
882 | if (!resets) |
883 | return ERR_PTR(-ENOMEM); | |
884 | ||
885 | for (i = 0; i < num; i++) { | |
c84b0326 | 886 | rstc = __of_reset_control_get(np, NULL, i, shared, optional, |
f31d5c24 | 887 | acquired); |
17c82e20 VG |
888 | if (IS_ERR(rstc)) |
889 | goto err_rst; | |
890 | resets->rstc[i] = rstc; | |
891 | } | |
892 | resets->num_rstcs = num; | |
893 | resets->base.array = true; | |
894 | ||
895 | return &resets->base; | |
896 | ||
897 | err_rst: | |
898 | mutex_lock(&reset_list_mutex); | |
899 | while (--i >= 0) | |
900 | __reset_control_put_internal(resets->rstc[i]); | |
901 | mutex_unlock(&reset_list_mutex); | |
902 | ||
903 | kfree(resets); | |
904 | ||
905 | return rstc; | |
906 | } | |
907 | EXPORT_SYMBOL_GPL(of_reset_control_array_get); | |
908 | ||
909 | /** | |
910 | * devm_reset_control_array_get - Resource managed reset control array get | |
911 | * | |
912 | * @dev: device that requests the list of reset controls | |
913 | * @shared: whether reset controls are shared or not | |
914 | * @optional: whether it is optional to get the reset controls | |
915 | * | |
916 | * The reset control array APIs are intended for a list of resets | |
917 | * that just have to be asserted or deasserted, without any | |
918 | * requirements on the order. | |
919 | * | |
920 | * Returns pointer to allocated reset_control_array on success or | |
921 | * error on failure | |
922 | */ | |
923 | struct reset_control * | |
924 | devm_reset_control_array_get(struct device *dev, bool shared, bool optional) | |
925 | { | |
926 | struct reset_control **devres; | |
927 | struct reset_control *rstc; | |
928 | ||
929 | devres = devres_alloc(devm_reset_control_release, sizeof(*devres), | |
930 | GFP_KERNEL); | |
931 | if (!devres) | |
932 | return ERR_PTR(-ENOMEM); | |
933 | ||
f31d5c24 | 934 | rstc = of_reset_control_array_get(dev->of_node, shared, optional, true); |
17c82e20 VG |
935 | if (IS_ERR(rstc)) { |
936 | devres_free(devres); | |
937 | return rstc; | |
938 | } | |
939 | ||
940 | *devres = rstc; | |
941 | devres_add(dev, devres); | |
942 | ||
943 | return rstc; | |
944 | } | |
945 | EXPORT_SYMBOL_GPL(devm_reset_control_array_get); | |
eaf91db0 GU |
946 | |
947 | static int reset_control_get_count_from_lookup(struct device *dev) | |
948 | { | |
949 | const struct reset_control_lookup *lookup; | |
151f72f4 | 950 | const char *dev_id; |
eaf91db0 GU |
951 | int count = 0; |
952 | ||
953 | if (!dev) | |
954 | return -EINVAL; | |
955 | ||
151f72f4 | 956 | dev_id = dev_name(dev); |
eaf91db0 GU |
957 | mutex_lock(&reset_lookup_mutex); |
958 | ||
959 | list_for_each_entry(lookup, &reset_lookup_list, list) { | |
960 | if (!strcmp(lookup->dev_id, dev_id)) | |
961 | count++; | |
962 | } | |
963 | ||
964 | mutex_unlock(&reset_lookup_mutex); | |
965 | ||
966 | if (count == 0) | |
967 | count = -ENOENT; | |
968 | ||
969 | return count; | |
970 | } | |
971 | ||
972 | /** | |
973 | * reset_control_get_count - Count number of resets available with a device | |
974 | * | |
975 | * @dev: device for which to return the number of resets | |
976 | * | |
977 | * Returns positive reset count on success, or error number on failure and | |
978 | * on count being zero. | |
979 | */ | |
980 | int reset_control_get_count(struct device *dev) | |
981 | { | |
982 | if (dev->of_node) | |
983 | return of_reset_control_get_count(dev->of_node); | |
984 | ||
985 | return reset_control_get_count_from_lookup(dev); | |
986 | } | |
987 | EXPORT_SYMBOL_GPL(reset_control_get_count); |