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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 | |
61fc4131 | 79 | * |
a48108c0 PZ |
80 | * This static translation function is used by default if of_xlate in |
81 | * :c:type:`reset_controller_dev` is not set. It is useful for all reset | |
82 | * controllers with 1:1 mapping, where reset lines can be indexed by number | |
83 | * without gaps. | |
61fc4131 | 84 | */ |
0c5b2b91 | 85 | static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, |
61fc4131 PZ |
86 | const struct of_phandle_args *reset_spec) |
87 | { | |
61fc4131 PZ |
88 | if (reset_spec->args[0] >= rcdev->nr_resets) |
89 | return -EINVAL; | |
90 | ||
91 | return reset_spec->args[0]; | |
92 | } | |
61fc4131 PZ |
93 | |
94 | /** | |
95 | * reset_controller_register - register a reset controller device | |
96 | * @rcdev: a pointer to the initialized reset controller device | |
97 | */ | |
98 | int reset_controller_register(struct reset_controller_dev *rcdev) | |
99 | { | |
100 | if (!rcdev->of_xlate) { | |
101 | rcdev->of_reset_n_cells = 1; | |
102 | rcdev->of_xlate = of_reset_simple_xlate; | |
103 | } | |
104 | ||
c15ddec2 HG |
105 | INIT_LIST_HEAD(&rcdev->reset_control_head); |
106 | ||
107 | mutex_lock(&reset_list_mutex); | |
61fc4131 | 108 | list_add(&rcdev->list, &reset_controller_list); |
c15ddec2 | 109 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
110 | |
111 | return 0; | |
112 | } | |
113 | EXPORT_SYMBOL_GPL(reset_controller_register); | |
114 | ||
115 | /** | |
116 | * reset_controller_unregister - unregister a reset controller device | |
117 | * @rcdev: a pointer to the reset controller device | |
118 | */ | |
119 | void reset_controller_unregister(struct reset_controller_dev *rcdev) | |
120 | { | |
c15ddec2 | 121 | mutex_lock(&reset_list_mutex); |
61fc4131 | 122 | list_del(&rcdev->list); |
c15ddec2 | 123 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
124 | } |
125 | EXPORT_SYMBOL_GPL(reset_controller_unregister); | |
126 | ||
8d5b5d5c MY |
127 | static void devm_reset_controller_release(struct device *dev, void *res) |
128 | { | |
129 | reset_controller_unregister(*(struct reset_controller_dev **)res); | |
130 | } | |
131 | ||
132 | /** | |
133 | * devm_reset_controller_register - resource managed reset_controller_register() | |
134 | * @dev: device that is registering this reset controller | |
135 | * @rcdev: a pointer to the initialized reset controller device | |
136 | * | |
137 | * Managed reset_controller_register(). For reset controllers registered by | |
138 | * this function, reset_controller_unregister() is automatically called on | |
139 | * driver detach. See reset_controller_register() for more information. | |
140 | */ | |
141 | int devm_reset_controller_register(struct device *dev, | |
142 | struct reset_controller_dev *rcdev) | |
143 | { | |
144 | struct reset_controller_dev **rcdevp; | |
145 | int ret; | |
146 | ||
147 | rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp), | |
148 | GFP_KERNEL); | |
149 | if (!rcdevp) | |
150 | return -ENOMEM; | |
151 | ||
152 | ret = reset_controller_register(rcdev); | |
153 | if (!ret) { | |
154 | *rcdevp = rcdev; | |
155 | devres_add(dev, rcdevp); | |
156 | } else { | |
157 | devres_free(rcdevp); | |
158 | } | |
159 | ||
160 | return ret; | |
161 | } | |
162 | EXPORT_SYMBOL_GPL(devm_reset_controller_register); | |
163 | ||
6691dffa BG |
164 | /** |
165 | * reset_controller_add_lookup - register a set of lookup entries | |
6691dffa BG |
166 | * @lookup: array of reset lookup entries |
167 | * @num_entries: number of entries in the lookup array | |
168 | */ | |
e2749bb9 | 169 | void reset_controller_add_lookup(struct reset_control_lookup *lookup, |
6691dffa BG |
170 | unsigned int num_entries) |
171 | { | |
172 | struct reset_control_lookup *entry; | |
173 | unsigned int i; | |
174 | ||
175 | mutex_lock(&reset_lookup_mutex); | |
176 | for (i = 0; i < num_entries; i++) { | |
177 | entry = &lookup[i]; | |
178 | ||
e2749bb9 BG |
179 | if (!entry->dev_id || !entry->provider) { |
180 | pr_warn("%s(): reset lookup entry badly specified, skipping\n", | |
6691dffa BG |
181 | __func__); |
182 | continue; | |
183 | } | |
184 | ||
6691dffa BG |
185 | list_add_tail(&entry->list, &reset_lookup_list); |
186 | } | |
187 | mutex_unlock(&reset_lookup_mutex); | |
188 | } | |
189 | EXPORT_SYMBOL_GPL(reset_controller_add_lookup); | |
190 | ||
17c82e20 VG |
191 | static inline struct reset_control_array * |
192 | rstc_to_array(struct reset_control *rstc) { | |
193 | return container_of(rstc, struct reset_control_array, base); | |
194 | } | |
195 | ||
196 | static int reset_control_array_reset(struct reset_control_array *resets) | |
197 | { | |
198 | int ret, i; | |
199 | ||
200 | for (i = 0; i < resets->num_rstcs; i++) { | |
201 | ret = reset_control_reset(resets->rstc[i]); | |
202 | if (ret) | |
203 | return ret; | |
204 | } | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | static int reset_control_array_assert(struct reset_control_array *resets) | |
210 | { | |
211 | int ret, i; | |
212 | ||
213 | for (i = 0; i < resets->num_rstcs; i++) { | |
214 | ret = reset_control_assert(resets->rstc[i]); | |
215 | if (ret) | |
216 | goto err; | |
217 | } | |
218 | ||
219 | return 0; | |
220 | ||
221 | err: | |
222 | while (i--) | |
223 | reset_control_deassert(resets->rstc[i]); | |
224 | return ret; | |
225 | } | |
226 | ||
227 | static int reset_control_array_deassert(struct reset_control_array *resets) | |
228 | { | |
229 | int ret, i; | |
230 | ||
231 | for (i = 0; i < resets->num_rstcs; i++) { | |
232 | ret = reset_control_deassert(resets->rstc[i]); | |
233 | if (ret) | |
234 | goto err; | |
235 | } | |
236 | ||
237 | return 0; | |
238 | ||
239 | err: | |
240 | while (i--) | |
241 | reset_control_assert(resets->rstc[i]); | |
242 | return ret; | |
243 | } | |
244 | ||
22815f18 TR |
245 | static int reset_control_array_acquire(struct reset_control_array *resets) |
246 | { | |
247 | unsigned int i; | |
248 | int err; | |
249 | ||
250 | for (i = 0; i < resets->num_rstcs; i++) { | |
251 | err = reset_control_acquire(resets->rstc[i]); | |
252 | if (err < 0) | |
253 | goto release; | |
254 | } | |
255 | ||
256 | return 0; | |
257 | ||
258 | release: | |
259 | while (i--) | |
260 | reset_control_release(resets->rstc[i]); | |
261 | ||
262 | return err; | |
263 | } | |
264 | ||
265 | static void reset_control_array_release(struct reset_control_array *resets) | |
266 | { | |
267 | unsigned int i; | |
268 | ||
269 | for (i = 0; i < resets->num_rstcs; i++) | |
270 | reset_control_release(resets->rstc[i]); | |
271 | } | |
272 | ||
17c82e20 VG |
273 | static inline bool reset_control_is_array(struct reset_control *rstc) |
274 | { | |
275 | return rstc->array; | |
276 | } | |
277 | ||
61fc4131 PZ |
278 | /** |
279 | * reset_control_reset - reset the controlled device | |
280 | * @rstc: reset controller | |
0b52297f | 281 | * |
7da33a37 MB |
282 | * On a shared reset line the actual reset pulse is only triggered once for the |
283 | * lifetime of the reset_control instance: for all but the first caller this is | |
284 | * a no-op. | |
285 | * Consumers must not use reset_control_(de)assert on shared reset lines when | |
286 | * reset_control_reset has been used. | |
bb475230 RO |
287 | * |
288 | * If rstc is NULL it is an optional reset and the function will just | |
289 | * return 0. | |
61fc4131 PZ |
290 | */ |
291 | int reset_control_reset(struct reset_control *rstc) | |
292 | { | |
7da33a37 MB |
293 | int ret; |
294 | ||
bb475230 RO |
295 | if (!rstc) |
296 | return 0; | |
297 | ||
298 | if (WARN_ON(IS_ERR(rstc))) | |
0b52297f HG |
299 | return -EINVAL; |
300 | ||
17c82e20 VG |
301 | if (reset_control_is_array(rstc)) |
302 | return reset_control_array_reset(rstc_to_array(rstc)); | |
303 | ||
7da33a37 MB |
304 | if (!rstc->rcdev->ops->reset) |
305 | return -ENOTSUPP; | |
306 | ||
307 | if (rstc->shared) { | |
308 | if (WARN_ON(atomic_read(&rstc->deassert_count) != 0)) | |
309 | return -EINVAL; | |
310 | ||
311 | if (atomic_inc_return(&rstc->triggered_count) != 1) | |
312 | return 0; | |
c84b0326 PZ |
313 | } else { |
314 | if (!rstc->acquired) | |
315 | return -EPERM; | |
7da33a37 | 316 | } |
61fc4131 | 317 | |
7da33a37 | 318 | ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); |
e5a1dade | 319 | if (rstc->shared && ret) |
7da33a37 MB |
320 | atomic_dec(&rstc->triggered_count); |
321 | ||
322 | return ret; | |
61fc4131 PZ |
323 | } |
324 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
325 | ||
326 | /** | |
327 | * reset_control_assert - asserts the reset line | |
328 | * @rstc: reset controller | |
0b52297f HG |
329 | * |
330 | * Calling this on an exclusive reset controller guarantees that the reset | |
331 | * will be asserted. When called on a shared reset controller the line may | |
332 | * still be deasserted, as long as other users keep it so. | |
333 | * | |
334 | * For shared reset controls a driver cannot expect the hw's registers and | |
335 | * internal state to be reset, but must be prepared for this to happen. | |
7da33a37 MB |
336 | * Consumers must not use reset_control_reset on shared reset lines when |
337 | * reset_control_(de)assert has been used. | |
bb475230 RO |
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 | * |
397 | * If rstc is NULL it is an optional reset and the function will just | |
398 | * return 0. | |
61fc4131 PZ |
399 | */ |
400 | int reset_control_deassert(struct reset_control *rstc) | |
401 | { | |
bb475230 RO |
402 | if (!rstc) |
403 | return 0; | |
404 | ||
405 | if (WARN_ON(IS_ERR(rstc))) | |
a3774e14 PZ |
406 | return -EINVAL; |
407 | ||
17c82e20 VG |
408 | if (reset_control_is_array(rstc)) |
409 | return reset_control_array_deassert(rstc_to_array(rstc)); | |
410 | ||
0b52297f | 411 | if (rstc->shared) { |
7da33a37 MB |
412 | if (WARN_ON(atomic_read(&rstc->triggered_count) != 0)) |
413 | return -EINVAL; | |
414 | ||
0b52297f HG |
415 | if (atomic_inc_return(&rstc->deassert_count) != 1) |
416 | return 0; | |
c84b0326 PZ |
417 | } else { |
418 | if (!rstc->acquired) { | |
419 | WARN(1, "reset %s (ID: %u) is not acquired\n", | |
420 | rcdev_name(rstc->rcdev), rstc->id); | |
421 | return -EPERM; | |
422 | } | |
0b52297f HG |
423 | } |
424 | ||
21240eb9 PZ |
425 | /* |
426 | * If the reset controller does not implement .deassert(), we assume | |
427 | * that it handles self-deasserting reset lines via .reset(). In that | |
428 | * case, the reset lines are deasserted by default. If that is not the | |
429 | * case, the reset controller driver should implement .deassert() and | |
430 | * return -ENOTSUPP. | |
431 | */ | |
432 | if (!rstc->rcdev->ops->deassert) | |
433 | return 0; | |
434 | ||
0b52297f | 435 | return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); |
61fc4131 PZ |
436 | } |
437 | EXPORT_SYMBOL_GPL(reset_control_deassert); | |
438 | ||
729de41b DN |
439 | /** |
440 | * reset_control_status - returns a negative errno if not supported, a | |
441 | * positive value if the reset line is asserted, or zero if the reset | |
bb475230 | 442 | * line is not asserted or if the desc is NULL (optional reset). |
729de41b DN |
443 | * @rstc: reset controller |
444 | */ | |
445 | int reset_control_status(struct reset_control *rstc) | |
446 | { | |
bb475230 RO |
447 | if (!rstc) |
448 | return 0; | |
449 | ||
17c82e20 | 450 | if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc)) |
a3774e14 PZ |
451 | return -EINVAL; |
452 | ||
729de41b DN |
453 | if (rstc->rcdev->ops->status) |
454 | return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); | |
455 | ||
39b4da71 | 456 | return -ENOTSUPP; |
729de41b DN |
457 | } |
458 | EXPORT_SYMBOL_GPL(reset_control_status); | |
459 | ||
c84b0326 PZ |
460 | /** |
461 | * reset_control_acquire() - acquires a reset control for exclusive use | |
462 | * @rstc: reset control | |
463 | * | |
464 | * This is used to explicitly acquire a reset control for exclusive use. Note | |
465 | * that exclusive resets are requested as acquired by default. In order for a | |
466 | * second consumer to be able to control the reset, the first consumer has to | |
467 | * release it first. Typically the easiest way to achieve this is to call the | |
468 | * reset_control_get_exclusive_released() to obtain an instance of the reset | |
469 | * control. Such reset controls are not acquired by default. | |
470 | * | |
471 | * Consumers implementing shared access to an exclusive reset need to follow | |
472 | * a specific protocol in order to work together. Before consumers can change | |
473 | * a reset they must acquire exclusive access using reset_control_acquire(). | |
474 | * After they are done operating the reset, they must release exclusive access | |
475 | * with a call to reset_control_release(). Consumers are not granted exclusive | |
476 | * access to the reset as long as another consumer hasn't released a reset. | |
477 | * | |
478 | * See also: reset_control_release() | |
479 | */ | |
480 | int reset_control_acquire(struct reset_control *rstc) | |
481 | { | |
482 | struct reset_control *rc; | |
483 | ||
484 | if (!rstc) | |
485 | return 0; | |
486 | ||
487 | if (WARN_ON(IS_ERR(rstc))) | |
488 | return -EINVAL; | |
489 | ||
22815f18 TR |
490 | if (reset_control_is_array(rstc)) |
491 | return reset_control_array_acquire(rstc_to_array(rstc)); | |
492 | ||
c84b0326 PZ |
493 | mutex_lock(&reset_list_mutex); |
494 | ||
495 | if (rstc->acquired) { | |
496 | mutex_unlock(&reset_list_mutex); | |
497 | return 0; | |
498 | } | |
499 | ||
500 | list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) { | |
501 | if (rstc != rc && rstc->id == rc->id) { | |
502 | if (rc->acquired) { | |
503 | mutex_unlock(&reset_list_mutex); | |
504 | return -EBUSY; | |
505 | } | |
506 | } | |
507 | } | |
508 | ||
509 | rstc->acquired = true; | |
510 | ||
511 | mutex_unlock(&reset_list_mutex); | |
512 | return 0; | |
513 | } | |
514 | EXPORT_SYMBOL_GPL(reset_control_acquire); | |
515 | ||
516 | /** | |
517 | * reset_control_release() - releases exclusive access to a reset control | |
518 | * @rstc: reset control | |
519 | * | |
520 | * Releases exclusive access right to a reset control previously obtained by a | |
521 | * call to reset_control_acquire(). Until a consumer calls this function, no | |
522 | * other consumers will be granted exclusive access. | |
523 | * | |
524 | * See also: reset_control_acquire() | |
525 | */ | |
526 | void reset_control_release(struct reset_control *rstc) | |
527 | { | |
528 | if (!rstc || WARN_ON(IS_ERR(rstc))) | |
529 | return; | |
530 | ||
22815f18 TR |
531 | if (reset_control_is_array(rstc)) |
532 | reset_control_array_release(rstc_to_array(rstc)); | |
533 | else | |
534 | rstc->acquired = false; | |
c84b0326 PZ |
535 | } |
536 | EXPORT_SYMBOL_GPL(reset_control_release); | |
537 | ||
62e24c57 | 538 | static struct reset_control *__reset_control_get_internal( |
c15ddec2 | 539 | struct reset_controller_dev *rcdev, |
c84b0326 | 540 | unsigned int index, bool shared, bool acquired) |
c15ddec2 HG |
541 | { |
542 | struct reset_control *rstc; | |
543 | ||
544 | lockdep_assert_held(&reset_list_mutex); | |
545 | ||
546 | list_for_each_entry(rstc, &rcdev->reset_control_head, list) { | |
547 | if (rstc->id == index) { | |
c84b0326 PZ |
548 | /* |
549 | * Allow creating a secondary exclusive reset_control | |
550 | * that is initially not acquired for an already | |
551 | * controlled reset line. | |
552 | */ | |
553 | if (!rstc->shared && !shared && !acquired) | |
554 | break; | |
555 | ||
0b52297f HG |
556 | if (WARN_ON(!rstc->shared || !shared)) |
557 | return ERR_PTR(-EBUSY); | |
558 | ||
d25e4334 | 559 | kref_get(&rstc->refcnt); |
c15ddec2 HG |
560 | return rstc; |
561 | } | |
562 | } | |
563 | ||
564 | rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); | |
565 | if (!rstc) | |
566 | return ERR_PTR(-ENOMEM); | |
567 | ||
568 | try_module_get(rcdev->owner); | |
569 | ||
570 | rstc->rcdev = rcdev; | |
571 | list_add(&rstc->list, &rcdev->reset_control_head); | |
572 | rstc->id = index; | |
d25e4334 | 573 | kref_init(&rstc->refcnt); |
c84b0326 | 574 | rstc->acquired = acquired; |
0b52297f | 575 | rstc->shared = shared; |
c15ddec2 HG |
576 | |
577 | return rstc; | |
578 | } | |
579 | ||
d25e4334 | 580 | static void __reset_control_release(struct kref *kref) |
c15ddec2 | 581 | { |
d25e4334 PZ |
582 | struct reset_control *rstc = container_of(kref, struct reset_control, |
583 | refcnt); | |
c15ddec2 | 584 | |
d25e4334 | 585 | lockdep_assert_held(&reset_list_mutex); |
c15ddec2 HG |
586 | |
587 | module_put(rstc->rcdev->owner); | |
588 | ||
589 | list_del(&rstc->list); | |
590 | kfree(rstc); | |
591 | } | |
592 | ||
d25e4334 PZ |
593 | static void __reset_control_put_internal(struct reset_control *rstc) |
594 | { | |
595 | lockdep_assert_held(&reset_list_mutex); | |
596 | ||
597 | kref_put(&rstc->refcnt, __reset_control_release); | |
598 | } | |
599 | ||
6c96f05c | 600 | struct reset_control *__of_reset_control_get(struct device_node *node, |
bb475230 | 601 | const char *id, int index, bool shared, |
c84b0326 | 602 | bool optional, bool acquired) |
61fc4131 | 603 | { |
d056c9b8 | 604 | struct reset_control *rstc; |
61fc4131 PZ |
605 | struct reset_controller_dev *r, *rcdev; |
606 | struct of_phandle_args args; | |
61fc4131 PZ |
607 | int rstc_id; |
608 | int ret; | |
609 | ||
6c96f05c HG |
610 | if (!node) |
611 | return ERR_PTR(-EINVAL); | |
612 | ||
613 | if (id) { | |
614 | index = of_property_match_string(node, | |
615 | "reset-names", id); | |
bb475230 RO |
616 | if (index == -EILSEQ) |
617 | return ERR_PTR(index); | |
6c96f05c | 618 | if (index < 0) |
bb475230 | 619 | return optional ? NULL : ERR_PTR(-ENOENT); |
6c96f05c HG |
620 | } |
621 | ||
fc0a5921 | 622 | ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
61fc4131 | 623 | index, &args); |
bb475230 | 624 | if (ret == -EINVAL) |
61fc4131 | 625 | return ERR_PTR(ret); |
bb475230 RO |
626 | if (ret) |
627 | return optional ? NULL : ERR_PTR(ret); | |
61fc4131 | 628 | |
c15ddec2 | 629 | mutex_lock(&reset_list_mutex); |
61fc4131 PZ |
630 | rcdev = NULL; |
631 | list_for_each_entry(r, &reset_controller_list, list) { | |
632 | if (args.np == r->of_node) { | |
633 | rcdev = r; | |
634 | break; | |
635 | } | |
636 | } | |
61fc4131 PZ |
637 | |
638 | if (!rcdev) { | |
b790c8ea GU |
639 | rstc = ERR_PTR(-EPROBE_DEFER); |
640 | goto out; | |
61fc4131 PZ |
641 | } |
642 | ||
e677774f | 643 | if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { |
b790c8ea GU |
644 | rstc = ERR_PTR(-EINVAL); |
645 | goto out; | |
e677774f MR |
646 | } |
647 | ||
61fc4131 PZ |
648 | rstc_id = rcdev->of_xlate(rcdev, &args); |
649 | if (rstc_id < 0) { | |
b790c8ea GU |
650 | rstc = ERR_PTR(rstc_id); |
651 | goto out; | |
61fc4131 PZ |
652 | } |
653 | ||
c15ddec2 | 654 | /* reset_list_mutex also protects the rcdev's reset_control list */ |
c84b0326 | 655 | rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired); |
61fc4131 | 656 | |
b790c8ea | 657 | out: |
c15ddec2 | 658 | mutex_unlock(&reset_list_mutex); |
b790c8ea | 659 | of_node_put(args.np); |
61fc4131 PZ |
660 | |
661 | return rstc; | |
662 | } | |
6c96f05c | 663 | EXPORT_SYMBOL_GPL(__of_reset_control_get); |
61fc4131 | 664 | |
e2749bb9 BG |
665 | static struct reset_controller_dev * |
666 | __reset_controller_by_name(const char *name) | |
667 | { | |
668 | struct reset_controller_dev *rcdev; | |
669 | ||
670 | lockdep_assert_held(&reset_list_mutex); | |
671 | ||
672 | list_for_each_entry(rcdev, &reset_controller_list, list) { | |
673 | if (!rcdev->dev) | |
674 | continue; | |
675 | ||
676 | if (!strcmp(name, dev_name(rcdev->dev))) | |
677 | return rcdev; | |
678 | } | |
679 | ||
680 | return NULL; | |
681 | } | |
682 | ||
6691dffa BG |
683 | static struct reset_control * |
684 | __reset_control_get_from_lookup(struct device *dev, const char *con_id, | |
c84b0326 | 685 | bool shared, bool optional, bool acquired) |
6691dffa BG |
686 | { |
687 | const struct reset_control_lookup *lookup; | |
e2749bb9 | 688 | struct reset_controller_dev *rcdev; |
6691dffa BG |
689 | const char *dev_id = dev_name(dev); |
690 | struct reset_control *rstc = NULL; | |
691 | ||
6691dffa BG |
692 | mutex_lock(&reset_lookup_mutex); |
693 | ||
694 | list_for_each_entry(lookup, &reset_lookup_list, list) { | |
695 | if (strcmp(lookup->dev_id, dev_id)) | |
696 | continue; | |
697 | ||
698 | if ((!con_id && !lookup->con_id) || | |
699 | ((con_id && lookup->con_id) && | |
700 | !strcmp(con_id, lookup->con_id))) { | |
701 | mutex_lock(&reset_list_mutex); | |
e2749bb9 BG |
702 | rcdev = __reset_controller_by_name(lookup->provider); |
703 | if (!rcdev) { | |
704 | mutex_unlock(&reset_list_mutex); | |
705 | mutex_unlock(&reset_lookup_mutex); | |
706 | /* Reset provider may not be ready yet. */ | |
707 | return ERR_PTR(-EPROBE_DEFER); | |
708 | } | |
709 | ||
710 | rstc = __reset_control_get_internal(rcdev, | |
6691dffa | 711 | lookup->index, |
c84b0326 | 712 | shared, acquired); |
6691dffa BG |
713 | mutex_unlock(&reset_list_mutex); |
714 | break; | |
715 | } | |
716 | } | |
717 | ||
718 | mutex_unlock(&reset_lookup_mutex); | |
719 | ||
720 | if (!rstc) | |
721 | return optional ? NULL : ERR_PTR(-ENOENT); | |
722 | ||
723 | return rstc; | |
724 | } | |
725 | ||
62e24c57 | 726 | struct reset_control *__reset_control_get(struct device *dev, const char *id, |
c84b0326 PZ |
727 | int index, bool shared, bool optional, |
728 | bool acquired) | |
62e24c57 | 729 | { |
c84b0326 PZ |
730 | if (WARN_ON(shared && acquired)) |
731 | return ERR_PTR(-EINVAL); | |
732 | ||
62e24c57 PZ |
733 | if (dev->of_node) |
734 | return __of_reset_control_get(dev->of_node, id, index, shared, | |
c84b0326 | 735 | optional, acquired); |
62e24c57 | 736 | |
c84b0326 PZ |
737 | return __reset_control_get_from_lookup(dev, id, shared, optional, |
738 | acquired); | |
62e24c57 PZ |
739 | } |
740 | EXPORT_SYMBOL_GPL(__reset_control_get); | |
741 | ||
17c82e20 VG |
742 | static void reset_control_array_put(struct reset_control_array *resets) |
743 | { | |
744 | int i; | |
745 | ||
746 | mutex_lock(&reset_list_mutex); | |
747 | for (i = 0; i < resets->num_rstcs; i++) | |
748 | __reset_control_put_internal(resets->rstc[i]); | |
749 | mutex_unlock(&reset_list_mutex); | |
532f9cd6 | 750 | kfree(resets); |
17c82e20 VG |
751 | } |
752 | ||
61fc4131 PZ |
753 | /** |
754 | * reset_control_put - free the reset controller | |
755 | * @rstc: reset controller | |
756 | */ | |
61fc4131 PZ |
757 | void reset_control_put(struct reset_control *rstc) |
758 | { | |
4891486f | 759 | if (IS_ERR_OR_NULL(rstc)) |
61fc4131 PZ |
760 | return; |
761 | ||
17c82e20 VG |
762 | if (reset_control_is_array(rstc)) { |
763 | reset_control_array_put(rstc_to_array(rstc)); | |
764 | return; | |
765 | } | |
766 | ||
c15ddec2 | 767 | mutex_lock(&reset_list_mutex); |
62e24c57 | 768 | __reset_control_put_internal(rstc); |
c15ddec2 | 769 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
770 | } |
771 | EXPORT_SYMBOL_GPL(reset_control_put); | |
772 | ||
773 | static void devm_reset_control_release(struct device *dev, void *res) | |
774 | { | |
775 | reset_control_put(*(struct reset_control **)res); | |
776 | } | |
777 | ||
6c96f05c | 778 | struct reset_control *__devm_reset_control_get(struct device *dev, |
bb475230 | 779 | const char *id, int index, bool shared, |
c84b0326 | 780 | bool optional, bool acquired) |
61fc4131 PZ |
781 | { |
782 | struct reset_control **ptr, *rstc; | |
783 | ||
784 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
785 | GFP_KERNEL); | |
786 | if (!ptr) | |
787 | return ERR_PTR(-ENOMEM); | |
788 | ||
c84b0326 | 789 | rstc = __reset_control_get(dev, id, index, shared, optional, acquired); |
db238086 | 790 | if (!IS_ERR_OR_NULL(rstc)) { |
61fc4131 PZ |
791 | *ptr = rstc; |
792 | devres_add(dev, ptr); | |
793 | } else { | |
794 | devres_free(ptr); | |
795 | } | |
796 | ||
797 | return rstc; | |
798 | } | |
6c96f05c | 799 | EXPORT_SYMBOL_GPL(__devm_reset_control_get); |
61fc4131 | 800 | |
61fc4131 PZ |
801 | /** |
802 | * device_reset - find reset controller associated with the device | |
803 | * and perform reset | |
804 | * @dev: device to be reset by the controller | |
1554bbd4 | 805 | * @optional: whether it is optional to reset the device |
61fc4131 | 806 | * |
1554bbd4 | 807 | * Convenience wrapper for __reset_control_get() and reset_control_reset(). |
61fc4131 PZ |
808 | * This is useful for the common case of devices with single, dedicated reset |
809 | * lines. | |
810 | */ | |
1554bbd4 | 811 | int __device_reset(struct device *dev, bool optional) |
61fc4131 PZ |
812 | { |
813 | struct reset_control *rstc; | |
814 | int ret; | |
815 | ||
c84b0326 | 816 | rstc = __reset_control_get(dev, NULL, 0, 0, optional, true); |
61fc4131 PZ |
817 | if (IS_ERR(rstc)) |
818 | return PTR_ERR(rstc); | |
819 | ||
820 | ret = reset_control_reset(rstc); | |
821 | ||
822 | reset_control_put(rstc); | |
823 | ||
824 | return ret; | |
825 | } | |
1554bbd4 | 826 | EXPORT_SYMBOL_GPL(__device_reset); |
17c82e20 | 827 | |
77d551b9 | 828 | /* |
17c82e20 VG |
829 | * APIs to manage an array of reset controls. |
830 | */ | |
77d551b9 | 831 | |
17c82e20 VG |
832 | /** |
833 | * of_reset_control_get_count - Count number of resets available with a device | |
834 | * | |
835 | * @node: device node that contains 'resets'. | |
836 | * | |
837 | * Returns positive reset count on success, or error number on failure and | |
838 | * on count being zero. | |
839 | */ | |
840 | static int of_reset_control_get_count(struct device_node *node) | |
841 | { | |
842 | int count; | |
843 | ||
844 | if (!node) | |
845 | return -EINVAL; | |
846 | ||
847 | count = of_count_phandle_with_args(node, "resets", "#reset-cells"); | |
848 | if (count == 0) | |
849 | count = -ENOENT; | |
850 | ||
851 | return count; | |
852 | } | |
853 | ||
854 | /** | |
855 | * of_reset_control_array_get - Get a list of reset controls using | |
856 | * device node. | |
857 | * | |
858 | * @np: device node for the device that requests the reset controls array | |
859 | * @shared: whether reset controls are shared or not | |
860 | * @optional: whether it is optional to get the reset controls | |
f31d5c24 TR |
861 | * @acquired: only one reset control may be acquired for a given controller |
862 | * and ID | |
17c82e20 | 863 | * |
723c0011 | 864 | * Returns pointer to allocated reset_control on success or error on failure |
17c82e20 VG |
865 | */ |
866 | struct reset_control * | |
f31d5c24 TR |
867 | of_reset_control_array_get(struct device_node *np, bool shared, bool optional, |
868 | bool acquired) | |
17c82e20 VG |
869 | { |
870 | struct reset_control_array *resets; | |
871 | struct reset_control *rstc; | |
872 | int num, i; | |
873 | ||
874 | num = of_reset_control_get_count(np); | |
875 | if (num < 0) | |
876 | return optional ? NULL : ERR_PTR(num); | |
877 | ||
acafe7e3 | 878 | resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL); |
17c82e20 VG |
879 | if (!resets) |
880 | return ERR_PTR(-ENOMEM); | |
881 | ||
882 | for (i = 0; i < num; i++) { | |
c84b0326 | 883 | rstc = __of_reset_control_get(np, NULL, i, shared, optional, |
f31d5c24 | 884 | acquired); |
17c82e20 VG |
885 | if (IS_ERR(rstc)) |
886 | goto err_rst; | |
887 | resets->rstc[i] = rstc; | |
888 | } | |
889 | resets->num_rstcs = num; | |
890 | resets->base.array = true; | |
891 | ||
892 | return &resets->base; | |
893 | ||
894 | err_rst: | |
895 | mutex_lock(&reset_list_mutex); | |
896 | while (--i >= 0) | |
897 | __reset_control_put_internal(resets->rstc[i]); | |
898 | mutex_unlock(&reset_list_mutex); | |
899 | ||
900 | kfree(resets); | |
901 | ||
902 | return rstc; | |
903 | } | |
904 | EXPORT_SYMBOL_GPL(of_reset_control_array_get); | |
905 | ||
906 | /** | |
907 | * devm_reset_control_array_get - Resource managed reset control array get | |
908 | * | |
909 | * @dev: device that requests the list of reset controls | |
910 | * @shared: whether reset controls are shared or not | |
911 | * @optional: whether it is optional to get the reset controls | |
912 | * | |
913 | * The reset control array APIs are intended for a list of resets | |
914 | * that just have to be asserted or deasserted, without any | |
915 | * requirements on the order. | |
916 | * | |
723c0011 | 917 | * Returns pointer to allocated reset_control on success or error on failure |
17c82e20 VG |
918 | */ |
919 | struct reset_control * | |
920 | devm_reset_control_array_get(struct device *dev, bool shared, bool optional) | |
921 | { | |
922 | struct reset_control **devres; | |
923 | struct reset_control *rstc; | |
924 | ||
925 | devres = devres_alloc(devm_reset_control_release, sizeof(*devres), | |
926 | GFP_KERNEL); | |
927 | if (!devres) | |
928 | return ERR_PTR(-ENOMEM); | |
929 | ||
f31d5c24 | 930 | rstc = of_reset_control_array_get(dev->of_node, shared, optional, true); |
db238086 | 931 | if (IS_ERR_OR_NULL(rstc)) { |
17c82e20 VG |
932 | devres_free(devres); |
933 | return rstc; | |
934 | } | |
935 | ||
936 | *devres = rstc; | |
937 | devres_add(dev, devres); | |
938 | ||
939 | return rstc; | |
940 | } | |
941 | EXPORT_SYMBOL_GPL(devm_reset_control_array_get); | |
eaf91db0 GU |
942 | |
943 | static int reset_control_get_count_from_lookup(struct device *dev) | |
944 | { | |
945 | const struct reset_control_lookup *lookup; | |
151f72f4 | 946 | const char *dev_id; |
eaf91db0 GU |
947 | int count = 0; |
948 | ||
949 | if (!dev) | |
950 | return -EINVAL; | |
951 | ||
151f72f4 | 952 | dev_id = dev_name(dev); |
eaf91db0 GU |
953 | mutex_lock(&reset_lookup_mutex); |
954 | ||
955 | list_for_each_entry(lookup, &reset_lookup_list, list) { | |
956 | if (!strcmp(lookup->dev_id, dev_id)) | |
957 | count++; | |
958 | } | |
959 | ||
960 | mutex_unlock(&reset_lookup_mutex); | |
961 | ||
962 | if (count == 0) | |
963 | count = -ENOENT; | |
964 | ||
965 | return count; | |
966 | } | |
967 | ||
968 | /** | |
969 | * reset_control_get_count - Count number of resets available with a device | |
970 | * | |
971 | * @dev: device for which to return the number of resets | |
972 | * | |
973 | * Returns positive reset count on success, or error number on failure and | |
974 | * on count being zero. | |
975 | */ | |
976 | int reset_control_get_count(struct device *dev) | |
977 | { | |
978 | if (dev->of_node) | |
979 | return of_reset_control_get_count(dev->of_node); | |
980 | ||
981 | return reset_control_get_count_from_lookup(dev); | |
982 | } | |
983 | EXPORT_SYMBOL_GPL(reset_control_get_count); |