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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); | |
a9457ed2 | 153 | if (ret) { |
8d5b5d5c | 154 | devres_free(rcdevp); |
a9457ed2 | 155 | return ret; |
8d5b5d5c MY |
156 | } |
157 | ||
a9457ed2 GU |
158 | *rcdevp = rcdev; |
159 | devres_add(dev, rcdevp); | |
160 | ||
8d5b5d5c MY |
161 | return ret; |
162 | } | |
163 | EXPORT_SYMBOL_GPL(devm_reset_controller_register); | |
164 | ||
6691dffa BG |
165 | /** |
166 | * reset_controller_add_lookup - register a set of lookup entries | |
6691dffa BG |
167 | * @lookup: array of reset lookup entries |
168 | * @num_entries: number of entries in the lookup array | |
169 | */ | |
e2749bb9 | 170 | void reset_controller_add_lookup(struct reset_control_lookup *lookup, |
6691dffa BG |
171 | unsigned int num_entries) |
172 | { | |
173 | struct reset_control_lookup *entry; | |
174 | unsigned int i; | |
175 | ||
176 | mutex_lock(&reset_lookup_mutex); | |
177 | for (i = 0; i < num_entries; i++) { | |
178 | entry = &lookup[i]; | |
179 | ||
e2749bb9 BG |
180 | if (!entry->dev_id || !entry->provider) { |
181 | pr_warn("%s(): reset lookup entry badly specified, skipping\n", | |
6691dffa BG |
182 | __func__); |
183 | continue; | |
184 | } | |
185 | ||
6691dffa BG |
186 | list_add_tail(&entry->list, &reset_lookup_list); |
187 | } | |
188 | mutex_unlock(&reset_lookup_mutex); | |
189 | } | |
190 | EXPORT_SYMBOL_GPL(reset_controller_add_lookup); | |
191 | ||
17c82e20 VG |
192 | static inline struct reset_control_array * |
193 | rstc_to_array(struct reset_control *rstc) { | |
194 | return container_of(rstc, struct reset_control_array, base); | |
195 | } | |
196 | ||
197 | static int reset_control_array_reset(struct reset_control_array *resets) | |
198 | { | |
199 | int ret, i; | |
200 | ||
201 | for (i = 0; i < resets->num_rstcs; i++) { | |
202 | ret = reset_control_reset(resets->rstc[i]); | |
203 | if (ret) | |
204 | return ret; | |
205 | } | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
210 | static int reset_control_array_assert(struct reset_control_array *resets) | |
211 | { | |
212 | int ret, i; | |
213 | ||
214 | for (i = 0; i < resets->num_rstcs; i++) { | |
215 | ret = reset_control_assert(resets->rstc[i]); | |
216 | if (ret) | |
217 | goto err; | |
218 | } | |
219 | ||
220 | return 0; | |
221 | ||
222 | err: | |
223 | while (i--) | |
224 | reset_control_deassert(resets->rstc[i]); | |
225 | return ret; | |
226 | } | |
227 | ||
228 | static int reset_control_array_deassert(struct reset_control_array *resets) | |
229 | { | |
230 | int ret, i; | |
231 | ||
232 | for (i = 0; i < resets->num_rstcs; i++) { | |
233 | ret = reset_control_deassert(resets->rstc[i]); | |
234 | if (ret) | |
235 | goto err; | |
236 | } | |
237 | ||
238 | return 0; | |
239 | ||
240 | err: | |
241 | while (i--) | |
242 | reset_control_assert(resets->rstc[i]); | |
243 | return ret; | |
244 | } | |
245 | ||
22815f18 TR |
246 | static int reset_control_array_acquire(struct reset_control_array *resets) |
247 | { | |
248 | unsigned int i; | |
249 | int err; | |
250 | ||
251 | for (i = 0; i < resets->num_rstcs; i++) { | |
252 | err = reset_control_acquire(resets->rstc[i]); | |
253 | if (err < 0) | |
254 | goto release; | |
255 | } | |
256 | ||
257 | return 0; | |
258 | ||
259 | release: | |
260 | while (i--) | |
261 | reset_control_release(resets->rstc[i]); | |
262 | ||
263 | return err; | |
264 | } | |
265 | ||
266 | static void reset_control_array_release(struct reset_control_array *resets) | |
267 | { | |
268 | unsigned int i; | |
269 | ||
270 | for (i = 0; i < resets->num_rstcs; i++) | |
271 | reset_control_release(resets->rstc[i]); | |
272 | } | |
273 | ||
17c82e20 VG |
274 | static inline bool reset_control_is_array(struct reset_control *rstc) |
275 | { | |
276 | return rstc->array; | |
277 | } | |
278 | ||
61fc4131 PZ |
279 | /** |
280 | * reset_control_reset - reset the controlled device | |
281 | * @rstc: reset controller | |
0b52297f | 282 | * |
7da33a37 MB |
283 | * On a shared reset line the actual reset pulse is only triggered once for the |
284 | * lifetime of the reset_control instance: for all but the first caller this is | |
285 | * a no-op. | |
286 | * Consumers must not use reset_control_(de)assert on shared reset lines when | |
287 | * reset_control_reset has been used. | |
bb475230 RO |
288 | * |
289 | * If rstc is NULL it is an optional reset and the function will just | |
290 | * return 0. | |
61fc4131 PZ |
291 | */ |
292 | int reset_control_reset(struct reset_control *rstc) | |
293 | { | |
7da33a37 MB |
294 | int ret; |
295 | ||
bb475230 RO |
296 | if (!rstc) |
297 | return 0; | |
298 | ||
299 | if (WARN_ON(IS_ERR(rstc))) | |
0b52297f HG |
300 | return -EINVAL; |
301 | ||
17c82e20 VG |
302 | if (reset_control_is_array(rstc)) |
303 | return reset_control_array_reset(rstc_to_array(rstc)); | |
304 | ||
7da33a37 MB |
305 | if (!rstc->rcdev->ops->reset) |
306 | return -ENOTSUPP; | |
307 | ||
308 | if (rstc->shared) { | |
309 | if (WARN_ON(atomic_read(&rstc->deassert_count) != 0)) | |
310 | return -EINVAL; | |
311 | ||
312 | if (atomic_inc_return(&rstc->triggered_count) != 1) | |
313 | return 0; | |
c84b0326 PZ |
314 | } else { |
315 | if (!rstc->acquired) | |
316 | return -EPERM; | |
7da33a37 | 317 | } |
61fc4131 | 318 | |
7da33a37 | 319 | ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); |
e5a1dade | 320 | if (rstc->shared && ret) |
7da33a37 MB |
321 | atomic_dec(&rstc->triggered_count); |
322 | ||
323 | return ret; | |
61fc4131 PZ |
324 | } |
325 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
326 | ||
327 | /** | |
328 | * reset_control_assert - asserts the reset line | |
329 | * @rstc: reset controller | |
0b52297f HG |
330 | * |
331 | * Calling this on an exclusive reset controller guarantees that the reset | |
332 | * will be asserted. When called on a shared reset controller the line may | |
333 | * still be deasserted, as long as other users keep it so. | |
334 | * | |
335 | * For shared reset controls a driver cannot expect the hw's registers and | |
336 | * internal state to be reset, but must be prepared for this to happen. | |
7da33a37 MB |
337 | * Consumers must not use reset_control_reset on shared reset lines when |
338 | * reset_control_(de)assert has been used. | |
bb475230 RO |
339 | * |
340 | * If rstc is NULL it is an optional reset and the function will just | |
341 | * return 0. | |
61fc4131 PZ |
342 | */ |
343 | int reset_control_assert(struct reset_control *rstc) | |
344 | { | |
bb475230 RO |
345 | if (!rstc) |
346 | return 0; | |
347 | ||
348 | if (WARN_ON(IS_ERR(rstc))) | |
a3774e14 PZ |
349 | return -EINVAL; |
350 | ||
17c82e20 VG |
351 | if (reset_control_is_array(rstc)) |
352 | return reset_control_array_assert(rstc_to_array(rstc)); | |
353 | ||
0b52297f | 354 | if (rstc->shared) { |
7da33a37 MB |
355 | if (WARN_ON(atomic_read(&rstc->triggered_count) != 0)) |
356 | return -EINVAL; | |
357 | ||
0b52297f HG |
358 | if (WARN_ON(atomic_read(&rstc->deassert_count) == 0)) |
359 | return -EINVAL; | |
360 | ||
361 | if (atomic_dec_return(&rstc->deassert_count) != 0) | |
362 | return 0; | |
21240eb9 PZ |
363 | |
364 | /* | |
365 | * Shared reset controls allow the reset line to be in any state | |
366 | * after this call, so doing nothing is a valid option. | |
367 | */ | |
368 | if (!rstc->rcdev->ops->assert) | |
369 | return 0; | |
370 | } else { | |
371 | /* | |
372 | * If the reset controller does not implement .assert(), there | |
373 | * is no way to guarantee that the reset line is asserted after | |
374 | * this call. | |
375 | */ | |
376 | if (!rstc->rcdev->ops->assert) | |
377 | return -ENOTSUPP; | |
c84b0326 PZ |
378 | |
379 | if (!rstc->acquired) { | |
380 | WARN(1, "reset %s (ID: %u) is not acquired\n", | |
381 | rcdev_name(rstc->rcdev), rstc->id); | |
382 | return -EPERM; | |
383 | } | |
0b52297f HG |
384 | } |
385 | ||
386 | return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); | |
61fc4131 PZ |
387 | } |
388 | EXPORT_SYMBOL_GPL(reset_control_assert); | |
389 | ||
390 | /** | |
391 | * reset_control_deassert - deasserts the reset line | |
392 | * @rstc: reset controller | |
0b52297f HG |
393 | * |
394 | * After calling this function, the reset is guaranteed to be deasserted. | |
7da33a37 MB |
395 | * Consumers must not use reset_control_reset on shared reset lines when |
396 | * reset_control_(de)assert has been used. | |
bb475230 RO |
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 | ||
6691dffa BG |
693 | mutex_lock(&reset_lookup_mutex); |
694 | ||
695 | list_for_each_entry(lookup, &reset_lookup_list, list) { | |
696 | if (strcmp(lookup->dev_id, dev_id)) | |
697 | continue; | |
698 | ||
699 | if ((!con_id && !lookup->con_id) || | |
700 | ((con_id && lookup->con_id) && | |
701 | !strcmp(con_id, lookup->con_id))) { | |
702 | mutex_lock(&reset_list_mutex); | |
e2749bb9 BG |
703 | rcdev = __reset_controller_by_name(lookup->provider); |
704 | if (!rcdev) { | |
705 | mutex_unlock(&reset_list_mutex); | |
706 | mutex_unlock(&reset_lookup_mutex); | |
707 | /* Reset provider may not be ready yet. */ | |
708 | return ERR_PTR(-EPROBE_DEFER); | |
709 | } | |
710 | ||
711 | rstc = __reset_control_get_internal(rcdev, | |
6691dffa | 712 | lookup->index, |
c84b0326 | 713 | shared, acquired); |
6691dffa BG |
714 | mutex_unlock(&reset_list_mutex); |
715 | break; | |
716 | } | |
717 | } | |
718 | ||
719 | mutex_unlock(&reset_lookup_mutex); | |
720 | ||
721 | if (!rstc) | |
722 | return optional ? NULL : ERR_PTR(-ENOENT); | |
723 | ||
724 | return rstc; | |
725 | } | |
726 | ||
62e24c57 | 727 | struct reset_control *__reset_control_get(struct device *dev, const char *id, |
c84b0326 PZ |
728 | int index, bool shared, bool optional, |
729 | bool acquired) | |
62e24c57 | 730 | { |
c84b0326 PZ |
731 | if (WARN_ON(shared && acquired)) |
732 | return ERR_PTR(-EINVAL); | |
733 | ||
62e24c57 PZ |
734 | if (dev->of_node) |
735 | return __of_reset_control_get(dev->of_node, id, index, shared, | |
c84b0326 | 736 | optional, acquired); |
62e24c57 | 737 | |
c84b0326 PZ |
738 | return __reset_control_get_from_lookup(dev, id, shared, optional, |
739 | acquired); | |
62e24c57 PZ |
740 | } |
741 | EXPORT_SYMBOL_GPL(__reset_control_get); | |
742 | ||
17c82e20 VG |
743 | static void reset_control_array_put(struct reset_control_array *resets) |
744 | { | |
745 | int i; | |
746 | ||
747 | mutex_lock(&reset_list_mutex); | |
748 | for (i = 0; i < resets->num_rstcs; i++) | |
749 | __reset_control_put_internal(resets->rstc[i]); | |
750 | mutex_unlock(&reset_list_mutex); | |
532f9cd6 | 751 | kfree(resets); |
17c82e20 VG |
752 | } |
753 | ||
61fc4131 PZ |
754 | /** |
755 | * reset_control_put - free the reset controller | |
756 | * @rstc: reset controller | |
757 | */ | |
61fc4131 PZ |
758 | void reset_control_put(struct reset_control *rstc) |
759 | { | |
4891486f | 760 | if (IS_ERR_OR_NULL(rstc)) |
61fc4131 PZ |
761 | return; |
762 | ||
17c82e20 VG |
763 | if (reset_control_is_array(rstc)) { |
764 | reset_control_array_put(rstc_to_array(rstc)); | |
765 | return; | |
766 | } | |
767 | ||
c15ddec2 | 768 | mutex_lock(&reset_list_mutex); |
62e24c57 | 769 | __reset_control_put_internal(rstc); |
c15ddec2 | 770 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
771 | } |
772 | EXPORT_SYMBOL_GPL(reset_control_put); | |
773 | ||
774 | static void devm_reset_control_release(struct device *dev, void *res) | |
775 | { | |
776 | reset_control_put(*(struct reset_control **)res); | |
777 | } | |
778 | ||
6c96f05c | 779 | struct reset_control *__devm_reset_control_get(struct device *dev, |
bb475230 | 780 | const char *id, int index, bool shared, |
c84b0326 | 781 | bool optional, bool acquired) |
61fc4131 PZ |
782 | { |
783 | struct reset_control **ptr, *rstc; | |
784 | ||
785 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
786 | GFP_KERNEL); | |
787 | if (!ptr) | |
788 | return ERR_PTR(-ENOMEM); | |
789 | ||
c84b0326 | 790 | rstc = __reset_control_get(dev, id, index, shared, optional, acquired); |
a9457ed2 | 791 | if (IS_ERR_OR_NULL(rstc)) { |
61fc4131 | 792 | devres_free(ptr); |
a9457ed2 | 793 | return rstc; |
61fc4131 PZ |
794 | } |
795 | ||
a9457ed2 GU |
796 | *ptr = rstc; |
797 | devres_add(dev, ptr); | |
798 | ||
61fc4131 PZ |
799 | return rstc; |
800 | } | |
6c96f05c | 801 | EXPORT_SYMBOL_GPL(__devm_reset_control_get); |
61fc4131 | 802 | |
61fc4131 PZ |
803 | /** |
804 | * device_reset - find reset controller associated with the device | |
805 | * and perform reset | |
806 | * @dev: device to be reset by the controller | |
1554bbd4 | 807 | * @optional: whether it is optional to reset the device |
61fc4131 | 808 | * |
1554bbd4 | 809 | * Convenience wrapper for __reset_control_get() and reset_control_reset(). |
61fc4131 PZ |
810 | * This is useful for the common case of devices with single, dedicated reset |
811 | * lines. | |
812 | */ | |
1554bbd4 | 813 | int __device_reset(struct device *dev, bool optional) |
61fc4131 PZ |
814 | { |
815 | struct reset_control *rstc; | |
816 | int ret; | |
817 | ||
c84b0326 | 818 | rstc = __reset_control_get(dev, NULL, 0, 0, optional, true); |
61fc4131 PZ |
819 | if (IS_ERR(rstc)) |
820 | return PTR_ERR(rstc); | |
821 | ||
822 | ret = reset_control_reset(rstc); | |
823 | ||
824 | reset_control_put(rstc); | |
825 | ||
826 | return ret; | |
827 | } | |
1554bbd4 | 828 | EXPORT_SYMBOL_GPL(__device_reset); |
17c82e20 | 829 | |
77d551b9 | 830 | /* |
17c82e20 VG |
831 | * APIs to manage an array of reset controls. |
832 | */ | |
77d551b9 | 833 | |
17c82e20 VG |
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 | 865 | * |
723c0011 | 866 | * Returns pointer to allocated reset_control on success or error on failure |
17c82e20 VG |
867 | */ |
868 | struct reset_control * | |
f31d5c24 TR |
869 | of_reset_control_array_get(struct device_node *np, bool shared, bool optional, |
870 | bool acquired) | |
17c82e20 VG |
871 | { |
872 | struct reset_control_array *resets; | |
873 | struct reset_control *rstc; | |
874 | int num, i; | |
875 | ||
876 | num = of_reset_control_get_count(np); | |
877 | if (num < 0) | |
878 | return optional ? NULL : ERR_PTR(num); | |
879 | ||
acafe7e3 | 880 | resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL); |
17c82e20 VG |
881 | if (!resets) |
882 | return ERR_PTR(-ENOMEM); | |
883 | ||
884 | for (i = 0; i < num; i++) { | |
c84b0326 | 885 | rstc = __of_reset_control_get(np, NULL, i, shared, optional, |
f31d5c24 | 886 | acquired); |
17c82e20 VG |
887 | if (IS_ERR(rstc)) |
888 | goto err_rst; | |
889 | resets->rstc[i] = rstc; | |
890 | } | |
891 | resets->num_rstcs = num; | |
892 | resets->base.array = true; | |
893 | ||
894 | return &resets->base; | |
895 | ||
896 | err_rst: | |
897 | mutex_lock(&reset_list_mutex); | |
898 | while (--i >= 0) | |
899 | __reset_control_put_internal(resets->rstc[i]); | |
900 | mutex_unlock(&reset_list_mutex); | |
901 | ||
902 | kfree(resets); | |
903 | ||
904 | return rstc; | |
905 | } | |
906 | EXPORT_SYMBOL_GPL(of_reset_control_array_get); | |
907 | ||
908 | /** | |
909 | * devm_reset_control_array_get - Resource managed reset control array get | |
910 | * | |
911 | * @dev: device that requests the list of reset controls | |
912 | * @shared: whether reset controls are shared or not | |
913 | * @optional: whether it is optional to get the reset controls | |
914 | * | |
915 | * The reset control array APIs are intended for a list of resets | |
916 | * that just have to be asserted or deasserted, without any | |
917 | * requirements on the order. | |
918 | * | |
723c0011 | 919 | * Returns pointer to allocated reset_control on success or error on failure |
17c82e20 VG |
920 | */ |
921 | struct reset_control * | |
922 | devm_reset_control_array_get(struct device *dev, bool shared, bool optional) | |
923 | { | |
a9457ed2 | 924 | struct reset_control **ptr, *rstc; |
17c82e20 | 925 | |
a9457ed2 GU |
926 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), |
927 | GFP_KERNEL); | |
928 | if (!ptr) | |
17c82e20 VG |
929 | return ERR_PTR(-ENOMEM); |
930 | ||
f31d5c24 | 931 | rstc = of_reset_control_array_get(dev->of_node, shared, optional, true); |
db238086 | 932 | if (IS_ERR_OR_NULL(rstc)) { |
a9457ed2 | 933 | devres_free(ptr); |
17c82e20 VG |
934 | return rstc; |
935 | } | |
936 | ||
a9457ed2 GU |
937 | *ptr = rstc; |
938 | devres_add(dev, ptr); | |
17c82e20 VG |
939 | |
940 | return rstc; | |
941 | } | |
942 | EXPORT_SYMBOL_GPL(devm_reset_control_array_get); | |
eaf91db0 GU |
943 | |
944 | static int reset_control_get_count_from_lookup(struct device *dev) | |
945 | { | |
946 | const struct reset_control_lookup *lookup; | |
151f72f4 | 947 | const char *dev_id; |
eaf91db0 GU |
948 | int count = 0; |
949 | ||
950 | if (!dev) | |
951 | return -EINVAL; | |
952 | ||
151f72f4 | 953 | dev_id = dev_name(dev); |
eaf91db0 GU |
954 | mutex_lock(&reset_lookup_mutex); |
955 | ||
956 | list_for_each_entry(lookup, &reset_lookup_list, list) { | |
957 | if (!strcmp(lookup->dev_id, dev_id)) | |
958 | count++; | |
959 | } | |
960 | ||
961 | mutex_unlock(&reset_lookup_mutex); | |
962 | ||
963 | if (count == 0) | |
964 | count = -ENOENT; | |
965 | ||
966 | return count; | |
967 | } | |
968 | ||
969 | /** | |
970 | * reset_control_get_count - Count number of resets available with a device | |
971 | * | |
972 | * @dev: device for which to return the number of resets | |
973 | * | |
974 | * Returns positive reset count on success, or error number on failure and | |
975 | * on count being zero. | |
976 | */ | |
977 | int reset_control_get_count(struct device *dev) | |
978 | { | |
979 | if (dev->of_node) | |
980 | return of_reset_control_get_count(dev->of_node); | |
981 | ||
982 | return reset_control_get_count_from_lookup(dev); | |
983 | } | |
984 | EXPORT_SYMBOL_GPL(reset_control_get_count); |