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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Reset Controller framework
4 *
5 * Copyright 2013 Philipp Zabel, Pengutronix
6 */
7#include <linux/atomic.h>
8#include <linux/cleanup.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/export.h>
12#include <linux/kernel.h>
13#include <linux/kref.h>
14#include <linux/gpio/driver.h>
15#include <linux/gpio/machine.h>
16#include <linux/idr.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/acpi.h>
20#include <linux/platform_device.h>
21#include <linux/reset.h>
22#include <linux/reset-controller.h>
23#include <linux/slab.h>
24
25static DEFINE_MUTEX(reset_list_mutex);
26static LIST_HEAD(reset_controller_list);
27
28static DEFINE_MUTEX(reset_lookup_mutex);
29static LIST_HEAD(reset_lookup_list);
30
31/* Protects reset_gpio_lookup_list */
32static DEFINE_MUTEX(reset_gpio_lookup_mutex);
33static LIST_HEAD(reset_gpio_lookup_list);
34static DEFINE_IDA(reset_gpio_ida);
35
36/**
37 * struct reset_control - a reset control
38 * @rcdev: a pointer to the reset controller device
39 * this reset control belongs to
40 * @list: list entry for the rcdev's reset controller list
41 * @id: ID of the reset controller in the reset
42 * controller device
43 * @refcnt: Number of gets of this reset_control
44 * @acquired: Only one reset_control may be acquired for a given rcdev and id.
45 * @shared: Is this a shared (1), or an exclusive (0) reset_control?
46 * @array: Is this an array of reset controls (1)?
47 * @deassert_count: Number of times this reset line has been deasserted
48 * @triggered_count: Number of times this reset line has been reset. Currently
49 * only used for shared resets, which means that the value
50 * will be either 0 or 1.
51 */
52struct reset_control {
53 struct reset_controller_dev *rcdev;
54 struct list_head list;
55 unsigned int id;
56 struct kref refcnt;
57 bool acquired;
58 bool shared;
59 bool array;
60 atomic_t deassert_count;
61 atomic_t triggered_count;
62};
63
64/**
65 * struct reset_control_array - an array of reset controls
66 * @base: reset control for compatibility with reset control API functions
67 * @num_rstcs: number of reset controls
68 * @rstc: array of reset controls
69 */
70struct reset_control_array {
71 struct reset_control base;
72 unsigned int num_rstcs;
73 struct reset_control *rstc[] __counted_by(num_rstcs);
74};
75
76/**
77 * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
78 * @of_args: phandle to the reset controller with all the args like GPIO number
79 * @list: list entry for the reset_gpio_lookup_list
80 */
81struct reset_gpio_lookup {
82 struct of_phandle_args of_args;
83 struct list_head list;
84};
85
86static const char *rcdev_name(struct reset_controller_dev *rcdev)
87{
88 if (rcdev->dev)
89 return dev_name(rcdev->dev);
90
91 if (rcdev->of_node)
92 return rcdev->of_node->full_name;
93
94 if (rcdev->of_args)
95 return rcdev->of_args->np->full_name;
96
97 return NULL;
98}
99
100/**
101 * of_reset_simple_xlate - translate reset_spec to the reset line number
102 * @rcdev: a pointer to the reset controller device
103 * @reset_spec: reset line specifier as found in the device tree
104 *
105 * This static translation function is used by default if of_xlate in
106 * :c:type:`reset_controller_dev` is not set. It is useful for all reset
107 * controllers with 1:1 mapping, where reset lines can be indexed by number
108 * without gaps.
109 */
110static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
111 const struct of_phandle_args *reset_spec)
112{
113 if (reset_spec->args[0] >= rcdev->nr_resets)
114 return -EINVAL;
115
116 return reset_spec->args[0];
117}
118
119/**
120 * reset_controller_register - register a reset controller device
121 * @rcdev: a pointer to the initialized reset controller device
122 */
123int reset_controller_register(struct reset_controller_dev *rcdev)
124{
125 if (rcdev->of_node && rcdev->of_args)
126 return -EINVAL;
127
128 if (!rcdev->of_xlate) {
129 rcdev->of_reset_n_cells = 1;
130 rcdev->of_xlate = of_reset_simple_xlate;
131 }
132
133 INIT_LIST_HEAD(&rcdev->reset_control_head);
134
135 mutex_lock(&reset_list_mutex);
136 list_add(&rcdev->list, &reset_controller_list);
137 mutex_unlock(&reset_list_mutex);
138
139 return 0;
140}
141EXPORT_SYMBOL_GPL(reset_controller_register);
142
143/**
144 * reset_controller_unregister - unregister a reset controller device
145 * @rcdev: a pointer to the reset controller device
146 */
147void reset_controller_unregister(struct reset_controller_dev *rcdev)
148{
149 mutex_lock(&reset_list_mutex);
150 list_del(&rcdev->list);
151 mutex_unlock(&reset_list_mutex);
152}
153EXPORT_SYMBOL_GPL(reset_controller_unregister);
154
155static void devm_reset_controller_release(struct device *dev, void *res)
156{
157 reset_controller_unregister(*(struct reset_controller_dev **)res);
158}
159
160/**
161 * devm_reset_controller_register - resource managed reset_controller_register()
162 * @dev: device that is registering this reset controller
163 * @rcdev: a pointer to the initialized reset controller device
164 *
165 * Managed reset_controller_register(). For reset controllers registered by
166 * this function, reset_controller_unregister() is automatically called on
167 * driver detach. See reset_controller_register() for more information.
168 */
169int devm_reset_controller_register(struct device *dev,
170 struct reset_controller_dev *rcdev)
171{
172 struct reset_controller_dev **rcdevp;
173 int ret;
174
175 rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
176 GFP_KERNEL);
177 if (!rcdevp)
178 return -ENOMEM;
179
180 ret = reset_controller_register(rcdev);
181 if (ret) {
182 devres_free(rcdevp);
183 return ret;
184 }
185
186 *rcdevp = rcdev;
187 devres_add(dev, rcdevp);
188
189 return ret;
190}
191EXPORT_SYMBOL_GPL(devm_reset_controller_register);
192
193/**
194 * reset_controller_add_lookup - register a set of lookup entries
195 * @lookup: array of reset lookup entries
196 * @num_entries: number of entries in the lookup array
197 */
198void reset_controller_add_lookup(struct reset_control_lookup *lookup,
199 unsigned int num_entries)
200{
201 struct reset_control_lookup *entry;
202 unsigned int i;
203
204 mutex_lock(&reset_lookup_mutex);
205 for (i = 0; i < num_entries; i++) {
206 entry = &lookup[i];
207
208 if (!entry->dev_id || !entry->provider) {
209 pr_warn("%s(): reset lookup entry badly specified, skipping\n",
210 __func__);
211 continue;
212 }
213
214 list_add_tail(&entry->list, &reset_lookup_list);
215 }
216 mutex_unlock(&reset_lookup_mutex);
217}
218EXPORT_SYMBOL_GPL(reset_controller_add_lookup);
219
220static inline struct reset_control_array *
221rstc_to_array(struct reset_control *rstc) {
222 return container_of(rstc, struct reset_control_array, base);
223}
224
225static int reset_control_array_reset(struct reset_control_array *resets)
226{
227 int ret, i;
228
229 for (i = 0; i < resets->num_rstcs; i++) {
230 ret = reset_control_reset(resets->rstc[i]);
231 if (ret)
232 return ret;
233 }
234
235 return 0;
236}
237
238static int reset_control_array_rearm(struct reset_control_array *resets)
239{
240 struct reset_control *rstc;
241 int i;
242
243 for (i = 0; i < resets->num_rstcs; i++) {
244 rstc = resets->rstc[i];
245
246 if (!rstc)
247 continue;
248
249 if (WARN_ON(IS_ERR(rstc)))
250 return -EINVAL;
251
252 if (rstc->shared) {
253 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
254 return -EINVAL;
255 } else {
256 if (!rstc->acquired)
257 return -EPERM;
258 }
259 }
260
261 for (i = 0; i < resets->num_rstcs; i++) {
262 rstc = resets->rstc[i];
263
264 if (rstc && rstc->shared)
265 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
266 }
267
268 return 0;
269}
270
271static int reset_control_array_assert(struct reset_control_array *resets)
272{
273 int ret, i;
274
275 for (i = 0; i < resets->num_rstcs; i++) {
276 ret = reset_control_assert(resets->rstc[i]);
277 if (ret)
278 goto err;
279 }
280
281 return 0;
282
283err:
284 while (i--)
285 reset_control_deassert(resets->rstc[i]);
286 return ret;
287}
288
289static int reset_control_array_deassert(struct reset_control_array *resets)
290{
291 int ret, i;
292
293 for (i = 0; i < resets->num_rstcs; i++) {
294 ret = reset_control_deassert(resets->rstc[i]);
295 if (ret)
296 goto err;
297 }
298
299 return 0;
300
301err:
302 while (i--)
303 reset_control_assert(resets->rstc[i]);
304 return ret;
305}
306
307static int reset_control_array_acquire(struct reset_control_array *resets)
308{
309 unsigned int i;
310 int err;
311
312 for (i = 0; i < resets->num_rstcs; i++) {
313 err = reset_control_acquire(resets->rstc[i]);
314 if (err < 0)
315 goto release;
316 }
317
318 return 0;
319
320release:
321 while (i--)
322 reset_control_release(resets->rstc[i]);
323
324 return err;
325}
326
327static void reset_control_array_release(struct reset_control_array *resets)
328{
329 unsigned int i;
330
331 for (i = 0; i < resets->num_rstcs; i++)
332 reset_control_release(resets->rstc[i]);
333}
334
335static inline bool reset_control_is_array(struct reset_control *rstc)
336{
337 return rstc->array;
338}
339
340/**
341 * reset_control_reset - reset the controlled device
342 * @rstc: reset controller
343 *
344 * On a shared reset line the actual reset pulse is only triggered once for the
345 * lifetime of the reset_control instance: for all but the first caller this is
346 * a no-op.
347 * Consumers must not use reset_control_(de)assert on shared reset lines when
348 * reset_control_reset has been used.
349 *
350 * If rstc is NULL it is an optional reset and the function will just
351 * return 0.
352 */
353int reset_control_reset(struct reset_control *rstc)
354{
355 int ret;
356
357 if (!rstc)
358 return 0;
359
360 if (WARN_ON(IS_ERR(rstc)))
361 return -EINVAL;
362
363 if (reset_control_is_array(rstc))
364 return reset_control_array_reset(rstc_to_array(rstc));
365
366 if (!rstc->rcdev->ops->reset)
367 return -ENOTSUPP;
368
369 if (rstc->shared) {
370 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
371 return -EINVAL;
372
373 if (atomic_inc_return(&rstc->triggered_count) != 1)
374 return 0;
375 } else {
376 if (!rstc->acquired)
377 return -EPERM;
378 }
379
380 ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
381 if (rstc->shared && ret)
382 atomic_dec(&rstc->triggered_count);
383
384 return ret;
385}
386EXPORT_SYMBOL_GPL(reset_control_reset);
387
388/**
389 * reset_control_bulk_reset - reset the controlled devices in order
390 * @num_rstcs: number of entries in rstcs array
391 * @rstcs: array of struct reset_control_bulk_data with reset controls set
392 *
393 * Issue a reset on all provided reset controls, in order.
394 *
395 * See also: reset_control_reset()
396 */
397int reset_control_bulk_reset(int num_rstcs,
398 struct reset_control_bulk_data *rstcs)
399{
400 int ret, i;
401
402 for (i = 0; i < num_rstcs; i++) {
403 ret = reset_control_reset(rstcs[i].rstc);
404 if (ret)
405 return ret;
406 }
407
408 return 0;
409}
410EXPORT_SYMBOL_GPL(reset_control_bulk_reset);
411
412/**
413 * reset_control_rearm - allow shared reset line to be re-triggered"
414 * @rstc: reset controller
415 *
416 * On a shared reset line the actual reset pulse is only triggered once for the
417 * lifetime of the reset_control instance, except if this call is used.
418 *
419 * Calls to this function must be balanced with calls to reset_control_reset,
420 * a warning is thrown in case triggered_count ever dips below 0.
421 *
422 * Consumers must not use reset_control_(de)assert on shared reset lines when
423 * reset_control_reset or reset_control_rearm have been used.
424 *
425 * If rstc is NULL the function will just return 0.
426 */
427int reset_control_rearm(struct reset_control *rstc)
428{
429 if (!rstc)
430 return 0;
431
432 if (WARN_ON(IS_ERR(rstc)))
433 return -EINVAL;
434
435 if (reset_control_is_array(rstc))
436 return reset_control_array_rearm(rstc_to_array(rstc));
437
438 if (rstc->shared) {
439 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
440 return -EINVAL;
441
442 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
443 } else {
444 if (!rstc->acquired)
445 return -EPERM;
446 }
447
448 return 0;
449}
450EXPORT_SYMBOL_GPL(reset_control_rearm);
451
452/**
453 * reset_control_assert - asserts the reset line
454 * @rstc: reset controller
455 *
456 * Calling this on an exclusive reset controller guarantees that the reset
457 * will be asserted. When called on a shared reset controller the line may
458 * still be deasserted, as long as other users keep it so.
459 *
460 * For shared reset controls a driver cannot expect the hw's registers and
461 * internal state to be reset, but must be prepared for this to happen.
462 * Consumers must not use reset_control_reset on shared reset lines when
463 * reset_control_(de)assert has been used.
464 *
465 * If rstc is NULL it is an optional reset and the function will just
466 * return 0.
467 */
468int reset_control_assert(struct reset_control *rstc)
469{
470 if (!rstc)
471 return 0;
472
473 if (WARN_ON(IS_ERR(rstc)))
474 return -EINVAL;
475
476 if (reset_control_is_array(rstc))
477 return reset_control_array_assert(rstc_to_array(rstc));
478
479 if (rstc->shared) {
480 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
481 return -EINVAL;
482
483 if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
484 return -EINVAL;
485
486 if (atomic_dec_return(&rstc->deassert_count) != 0)
487 return 0;
488
489 /*
490 * Shared reset controls allow the reset line to be in any state
491 * after this call, so doing nothing is a valid option.
492 */
493 if (!rstc->rcdev->ops->assert)
494 return 0;
495 } else {
496 /*
497 * If the reset controller does not implement .assert(), there
498 * is no way to guarantee that the reset line is asserted after
499 * this call.
500 */
501 if (!rstc->rcdev->ops->assert)
502 return -ENOTSUPP;
503
504 if (!rstc->acquired) {
505 WARN(1, "reset %s (ID: %u) is not acquired\n",
506 rcdev_name(rstc->rcdev), rstc->id);
507 return -EPERM;
508 }
509 }
510
511 return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
512}
513EXPORT_SYMBOL_GPL(reset_control_assert);
514
515/**
516 * reset_control_bulk_assert - asserts the reset lines in order
517 * @num_rstcs: number of entries in rstcs array
518 * @rstcs: array of struct reset_control_bulk_data with reset controls set
519 *
520 * Assert the reset lines for all provided reset controls, in order.
521 * If an assertion fails, already asserted resets are deasserted again.
522 *
523 * See also: reset_control_assert()
524 */
525int reset_control_bulk_assert(int num_rstcs,
526 struct reset_control_bulk_data *rstcs)
527{
528 int ret, i;
529
530 for (i = 0; i < num_rstcs; i++) {
531 ret = reset_control_assert(rstcs[i].rstc);
532 if (ret)
533 goto err;
534 }
535
536 return 0;
537
538err:
539 while (i--)
540 reset_control_deassert(rstcs[i].rstc);
541 return ret;
542}
543EXPORT_SYMBOL_GPL(reset_control_bulk_assert);
544
545/**
546 * reset_control_deassert - deasserts the reset line
547 * @rstc: reset controller
548 *
549 * After calling this function, the reset is guaranteed to be deasserted.
550 * Consumers must not use reset_control_reset on shared reset lines when
551 * reset_control_(de)assert has been used.
552 *
553 * If rstc is NULL it is an optional reset and the function will just
554 * return 0.
555 */
556int reset_control_deassert(struct reset_control *rstc)
557{
558 if (!rstc)
559 return 0;
560
561 if (WARN_ON(IS_ERR(rstc)))
562 return -EINVAL;
563
564 if (reset_control_is_array(rstc))
565 return reset_control_array_deassert(rstc_to_array(rstc));
566
567 if (rstc->shared) {
568 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
569 return -EINVAL;
570
571 if (atomic_inc_return(&rstc->deassert_count) != 1)
572 return 0;
573 } else {
574 if (!rstc->acquired) {
575 WARN(1, "reset %s (ID: %u) is not acquired\n",
576 rcdev_name(rstc->rcdev), rstc->id);
577 return -EPERM;
578 }
579 }
580
581 /*
582 * If the reset controller does not implement .deassert(), we assume
583 * that it handles self-deasserting reset lines via .reset(). In that
584 * case, the reset lines are deasserted by default. If that is not the
585 * case, the reset controller driver should implement .deassert() and
586 * return -ENOTSUPP.
587 */
588 if (!rstc->rcdev->ops->deassert)
589 return 0;
590
591 return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
592}
593EXPORT_SYMBOL_GPL(reset_control_deassert);
594
595/**
596 * reset_control_bulk_deassert - deasserts the reset lines in reverse order
597 * @num_rstcs: number of entries in rstcs array
598 * @rstcs: array of struct reset_control_bulk_data with reset controls set
599 *
600 * Deassert the reset lines for all provided reset controls, in reverse order.
601 * If a deassertion fails, already deasserted resets are asserted again.
602 *
603 * See also: reset_control_deassert()
604 */
605int reset_control_bulk_deassert(int num_rstcs,
606 struct reset_control_bulk_data *rstcs)
607{
608 int ret, i;
609
610 for (i = num_rstcs - 1; i >= 0; i--) {
611 ret = reset_control_deassert(rstcs[i].rstc);
612 if (ret)
613 goto err;
614 }
615
616 return 0;
617
618err:
619 while (i < num_rstcs)
620 reset_control_assert(rstcs[i++].rstc);
621 return ret;
622}
623EXPORT_SYMBOL_GPL(reset_control_bulk_deassert);
624
625/**
626 * reset_control_status - returns a negative errno if not supported, a
627 * positive value if the reset line is asserted, or zero if the reset
628 * line is not asserted or if the desc is NULL (optional reset).
629 * @rstc: reset controller
630 */
631int reset_control_status(struct reset_control *rstc)
632{
633 if (!rstc)
634 return 0;
635
636 if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc))
637 return -EINVAL;
638
639 if (rstc->rcdev->ops->status)
640 return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
641
642 return -ENOTSUPP;
643}
644EXPORT_SYMBOL_GPL(reset_control_status);
645
646/**
647 * reset_control_acquire() - acquires a reset control for exclusive use
648 * @rstc: reset control
649 *
650 * This is used to explicitly acquire a reset control for exclusive use. Note
651 * that exclusive resets are requested as acquired by default. In order for a
652 * second consumer to be able to control the reset, the first consumer has to
653 * release it first. Typically the easiest way to achieve this is to call the
654 * reset_control_get_exclusive_released() to obtain an instance of the reset
655 * control. Such reset controls are not acquired by default.
656 *
657 * Consumers implementing shared access to an exclusive reset need to follow
658 * a specific protocol in order to work together. Before consumers can change
659 * a reset they must acquire exclusive access using reset_control_acquire().
660 * After they are done operating the reset, they must release exclusive access
661 * with a call to reset_control_release(). Consumers are not granted exclusive
662 * access to the reset as long as another consumer hasn't released a reset.
663 *
664 * See also: reset_control_release()
665 */
666int reset_control_acquire(struct reset_control *rstc)
667{
668 struct reset_control *rc;
669
670 if (!rstc)
671 return 0;
672
673 if (WARN_ON(IS_ERR(rstc)))
674 return -EINVAL;
675
676 if (reset_control_is_array(rstc))
677 return reset_control_array_acquire(rstc_to_array(rstc));
678
679 mutex_lock(&reset_list_mutex);
680
681 if (rstc->acquired) {
682 mutex_unlock(&reset_list_mutex);
683 return 0;
684 }
685
686 list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {
687 if (rstc != rc && rstc->id == rc->id) {
688 if (rc->acquired) {
689 mutex_unlock(&reset_list_mutex);
690 return -EBUSY;
691 }
692 }
693 }
694
695 rstc->acquired = true;
696
697 mutex_unlock(&reset_list_mutex);
698 return 0;
699}
700EXPORT_SYMBOL_GPL(reset_control_acquire);
701
702/**
703 * reset_control_bulk_acquire - acquires reset controls for exclusive use
704 * @num_rstcs: number of entries in rstcs array
705 * @rstcs: array of struct reset_control_bulk_data with reset controls set
706 *
707 * This is used to explicitly acquire reset controls requested with
708 * reset_control_bulk_get_exclusive_release() for temporary exclusive use.
709 *
710 * See also: reset_control_acquire(), reset_control_bulk_release()
711 */
712int reset_control_bulk_acquire(int num_rstcs,
713 struct reset_control_bulk_data *rstcs)
714{
715 int ret, i;
716
717 for (i = 0; i < num_rstcs; i++) {
718 ret = reset_control_acquire(rstcs[i].rstc);
719 if (ret)
720 goto err;
721 }
722
723 return 0;
724
725err:
726 while (i--)
727 reset_control_release(rstcs[i].rstc);
728 return ret;
729}
730EXPORT_SYMBOL_GPL(reset_control_bulk_acquire);
731
732/**
733 * reset_control_release() - releases exclusive access to a reset control
734 * @rstc: reset control
735 *
736 * Releases exclusive access right to a reset control previously obtained by a
737 * call to reset_control_acquire(). Until a consumer calls this function, no
738 * other consumers will be granted exclusive access.
739 *
740 * See also: reset_control_acquire()
741 */
742void reset_control_release(struct reset_control *rstc)
743{
744 if (!rstc || WARN_ON(IS_ERR(rstc)))
745 return;
746
747 if (reset_control_is_array(rstc))
748 reset_control_array_release(rstc_to_array(rstc));
749 else
750 rstc->acquired = false;
751}
752EXPORT_SYMBOL_GPL(reset_control_release);
753
754/**
755 * reset_control_bulk_release() - releases exclusive access to reset controls
756 * @num_rstcs: number of entries in rstcs array
757 * @rstcs: array of struct reset_control_bulk_data with reset controls set
758 *
759 * Releases exclusive access right to reset controls previously obtained by a
760 * call to reset_control_bulk_acquire().
761 *
762 * See also: reset_control_release(), reset_control_bulk_acquire()
763 */
764void reset_control_bulk_release(int num_rstcs,
765 struct reset_control_bulk_data *rstcs)
766{
767 int i;
768
769 for (i = 0; i < num_rstcs; i++)
770 reset_control_release(rstcs[i].rstc);
771}
772EXPORT_SYMBOL_GPL(reset_control_bulk_release);
773
774static struct reset_control *
775__reset_control_get_internal(struct reset_controller_dev *rcdev,
776 unsigned int index, bool shared, bool acquired)
777{
778 struct reset_control *rstc;
779
780 lockdep_assert_held(&reset_list_mutex);
781
782 list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
783 if (rstc->id == index) {
784 /*
785 * Allow creating a secondary exclusive reset_control
786 * that is initially not acquired for an already
787 * controlled reset line.
788 */
789 if (!rstc->shared && !shared && !acquired)
790 break;
791
792 if (WARN_ON(!rstc->shared || !shared))
793 return ERR_PTR(-EBUSY);
794
795 kref_get(&rstc->refcnt);
796 return rstc;
797 }
798 }
799
800 rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
801 if (!rstc)
802 return ERR_PTR(-ENOMEM);
803
804 if (!try_module_get(rcdev->owner)) {
805 kfree(rstc);
806 return ERR_PTR(-ENODEV);
807 }
808
809 rstc->rcdev = rcdev;
810 list_add(&rstc->list, &rcdev->reset_control_head);
811 rstc->id = index;
812 kref_init(&rstc->refcnt);
813 rstc->acquired = acquired;
814 rstc->shared = shared;
815
816 return rstc;
817}
818
819static void __reset_control_release(struct kref *kref)
820{
821 struct reset_control *rstc = container_of(kref, struct reset_control,
822 refcnt);
823
824 lockdep_assert_held(&reset_list_mutex);
825
826 module_put(rstc->rcdev->owner);
827
828 list_del(&rstc->list);
829 kfree(rstc);
830}
831
832static void __reset_control_put_internal(struct reset_control *rstc)
833{
834 lockdep_assert_held(&reset_list_mutex);
835
836 if (IS_ERR_OR_NULL(rstc))
837 return;
838
839 kref_put(&rstc->refcnt, __reset_control_release);
840}
841
842static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
843 unsigned int gpio,
844 unsigned int of_flags)
845{
846 const struct fwnode_handle *fwnode = of_fwnode_handle(np);
847 unsigned int lookup_flags;
848 const char *label_tmp;
849
850 /*
851 * Later we map GPIO flags between OF and Linux, however not all
852 * constants from include/dt-bindings/gpio/gpio.h and
853 * include/linux/gpio/machine.h match each other.
854 */
855 if (of_flags > GPIO_ACTIVE_LOW) {
856 pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
857 of_flags, gpio);
858 return -EINVAL;
859 }
860
861 struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
862 if (!gdev)
863 return -EPROBE_DEFER;
864
865 label_tmp = gpio_device_get_label(gdev);
866 if (!label_tmp)
867 return -EINVAL;
868
869 char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
870 if (!label)
871 return -ENOMEM;
872
873 /* Size: one lookup entry plus sentinel */
874 struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
875 GFP_KERNEL);
876 if (!lookup)
877 return -ENOMEM;
878
879 lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
880 if (!lookup->dev_id)
881 return -ENOMEM;
882
883 lookup_flags = GPIO_PERSISTENT;
884 lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
885 lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
886 lookup_flags);
887
888 /* Not freed on success, because it is persisent subsystem data. */
889 gpiod_add_lookup_table(no_free_ptr(lookup));
890
891 return 0;
892}
893
894/*
895 * @args: phandle to the GPIO provider with all the args like GPIO number
896 */
897static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
898{
899 struct reset_gpio_lookup *rgpio_dev;
900 struct platform_device *pdev;
901 int id, ret;
902
903 /*
904 * Currently only #gpio-cells=2 is supported with the meaning of:
905 * args[0]: GPIO number
906 * args[1]: GPIO flags
907 * TODO: Handle other cases.
908 */
909 if (args->args_count != 2)
910 return -ENOENT;
911
912 /*
913 * Registering reset-gpio device might cause immediate
914 * bind, resulting in its probe() registering new reset controller thus
915 * taking reset_list_mutex lock via reset_controller_register().
916 */
917 lockdep_assert_not_held(&reset_list_mutex);
918
919 mutex_lock(&reset_gpio_lookup_mutex);
920
921 list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
922 if (args->np == rgpio_dev->of_args.np) {
923 if (of_phandle_args_equal(args, &rgpio_dev->of_args))
924 goto out; /* Already on the list, done */
925 }
926 }
927
928 id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
929 if (id < 0) {
930 ret = id;
931 goto err_unlock;
932 }
933
934 /* Not freed on success, because it is persisent subsystem data. */
935 rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
936 if (!rgpio_dev) {
937 ret = -ENOMEM;
938 goto err_ida_free;
939 }
940
941 ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
942 args->args[1]);
943 if (ret < 0)
944 goto err_kfree;
945
946 rgpio_dev->of_args = *args;
947 /*
948 * We keep the device_node reference, but of_args.np is put at the end
949 * of __of_reset_control_get(), so get it one more time.
950 * Hold reference as long as rgpio_dev memory is valid.
951 */
952 of_node_get(rgpio_dev->of_args.np);
953 pdev = platform_device_register_data(NULL, "reset-gpio", id,
954 &rgpio_dev->of_args,
955 sizeof(rgpio_dev->of_args));
956 ret = PTR_ERR_OR_ZERO(pdev);
957 if (ret)
958 goto err_put;
959
960 list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
961
962out:
963 mutex_unlock(&reset_gpio_lookup_mutex);
964
965 return 0;
966
967err_put:
968 of_node_put(rgpio_dev->of_args.np);
969err_kfree:
970 kfree(rgpio_dev);
971err_ida_free:
972 ida_free(&reset_gpio_ida, id);
973err_unlock:
974 mutex_unlock(&reset_gpio_lookup_mutex);
975
976 return ret;
977}
978
979static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
980 bool gpio_fallback)
981{
982 struct reset_controller_dev *rcdev;
983
984 lockdep_assert_held(&reset_list_mutex);
985
986 list_for_each_entry(rcdev, &reset_controller_list, list) {
987 if (gpio_fallback) {
988 if (rcdev->of_args && of_phandle_args_equal(args,
989 rcdev->of_args))
990 return rcdev;
991 } else {
992 if (args->np == rcdev->of_node)
993 return rcdev;
994 }
995 }
996
997 return NULL;
998}
999
1000struct reset_control *
1001__of_reset_control_get(struct device_node *node, const char *id, int index,
1002 bool shared, bool optional, bool acquired)
1003{
1004 bool gpio_fallback = false;
1005 struct reset_control *rstc;
1006 struct reset_controller_dev *rcdev;
1007 struct of_phandle_args args;
1008 int rstc_id;
1009 int ret;
1010
1011 if (!node)
1012 return ERR_PTR(-EINVAL);
1013
1014 if (id) {
1015 index = of_property_match_string(node,
1016 "reset-names", id);
1017 if (index == -EILSEQ)
1018 return ERR_PTR(index);
1019 if (index < 0)
1020 return optional ? NULL : ERR_PTR(-ENOENT);
1021 }
1022
1023 ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
1024 index, &args);
1025 if (ret == -EINVAL)
1026 return ERR_PTR(ret);
1027 if (ret) {
1028 if (!IS_ENABLED(CONFIG_RESET_GPIO))
1029 return optional ? NULL : ERR_PTR(ret);
1030
1031 /*
1032 * There can be only one reset-gpio for regular devices, so
1033 * don't bother with the "reset-gpios" phandle index.
1034 */
1035 ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",
1036 0, &args);
1037 if (ret)
1038 return optional ? NULL : ERR_PTR(ret);
1039
1040 gpio_fallback = true;
1041
1042 ret = __reset_add_reset_gpio_device(&args);
1043 if (ret) {
1044 rstc = ERR_PTR(ret);
1045 goto out_put;
1046 }
1047 }
1048
1049 mutex_lock(&reset_list_mutex);
1050 rcdev = __reset_find_rcdev(&args, gpio_fallback);
1051 if (!rcdev) {
1052 rstc = ERR_PTR(-EPROBE_DEFER);
1053 goto out_unlock;
1054 }
1055
1056 if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
1057 rstc = ERR_PTR(-EINVAL);
1058 goto out_unlock;
1059 }
1060
1061 rstc_id = rcdev->of_xlate(rcdev, &args);
1062 if (rstc_id < 0) {
1063 rstc = ERR_PTR(rstc_id);
1064 goto out_unlock;
1065 }
1066
1067 /* reset_list_mutex also protects the rcdev's reset_control list */
1068 rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
1069
1070out_unlock:
1071 mutex_unlock(&reset_list_mutex);
1072out_put:
1073 of_node_put(args.np);
1074
1075 return rstc;
1076}
1077EXPORT_SYMBOL_GPL(__of_reset_control_get);
1078
1079static struct reset_controller_dev *
1080__reset_controller_by_name(const char *name)
1081{
1082 struct reset_controller_dev *rcdev;
1083
1084 lockdep_assert_held(&reset_list_mutex);
1085
1086 list_for_each_entry(rcdev, &reset_controller_list, list) {
1087 if (!rcdev->dev)
1088 continue;
1089
1090 if (!strcmp(name, dev_name(rcdev->dev)))
1091 return rcdev;
1092 }
1093
1094 return NULL;
1095}
1096
1097static struct reset_control *
1098__reset_control_get_from_lookup(struct device *dev, const char *con_id,
1099 bool shared, bool optional, bool acquired)
1100{
1101 const struct reset_control_lookup *lookup;
1102 struct reset_controller_dev *rcdev;
1103 const char *dev_id = dev_name(dev);
1104 struct reset_control *rstc = NULL;
1105
1106 mutex_lock(&reset_lookup_mutex);
1107
1108 list_for_each_entry(lookup, &reset_lookup_list, list) {
1109 if (strcmp(lookup->dev_id, dev_id))
1110 continue;
1111
1112 if ((!con_id && !lookup->con_id) ||
1113 ((con_id && lookup->con_id) &&
1114 !strcmp(con_id, lookup->con_id))) {
1115 mutex_lock(&reset_list_mutex);
1116 rcdev = __reset_controller_by_name(lookup->provider);
1117 if (!rcdev) {
1118 mutex_unlock(&reset_list_mutex);
1119 mutex_unlock(&reset_lookup_mutex);
1120 /* Reset provider may not be ready yet. */
1121 return ERR_PTR(-EPROBE_DEFER);
1122 }
1123
1124 rstc = __reset_control_get_internal(rcdev,
1125 lookup->index,
1126 shared, acquired);
1127 mutex_unlock(&reset_list_mutex);
1128 break;
1129 }
1130 }
1131
1132 mutex_unlock(&reset_lookup_mutex);
1133
1134 if (!rstc)
1135 return optional ? NULL : ERR_PTR(-ENOENT);
1136
1137 return rstc;
1138}
1139
1140struct reset_control *__reset_control_get(struct device *dev, const char *id,
1141 int index, bool shared, bool optional,
1142 bool acquired)
1143{
1144 if (WARN_ON(shared && acquired))
1145 return ERR_PTR(-EINVAL);
1146
1147 if (dev->of_node)
1148 return __of_reset_control_get(dev->of_node, id, index, shared,
1149 optional, acquired);
1150
1151 return __reset_control_get_from_lookup(dev, id, shared, optional,
1152 acquired);
1153}
1154EXPORT_SYMBOL_GPL(__reset_control_get);
1155
1156int __reset_control_bulk_get(struct device *dev, int num_rstcs,
1157 struct reset_control_bulk_data *rstcs,
1158 bool shared, bool optional, bool acquired)
1159{
1160 int ret, i;
1161
1162 for (i = 0; i < num_rstcs; i++) {
1163 rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0,
1164 shared, optional, acquired);
1165 if (IS_ERR(rstcs[i].rstc)) {
1166 ret = PTR_ERR(rstcs[i].rstc);
1167 goto err;
1168 }
1169 }
1170
1171 return 0;
1172
1173err:
1174 mutex_lock(&reset_list_mutex);
1175 while (i--)
1176 __reset_control_put_internal(rstcs[i].rstc);
1177 mutex_unlock(&reset_list_mutex);
1178 return ret;
1179}
1180EXPORT_SYMBOL_GPL(__reset_control_bulk_get);
1181
1182static void reset_control_array_put(struct reset_control_array *resets)
1183{
1184 int i;
1185
1186 mutex_lock(&reset_list_mutex);
1187 for (i = 0; i < resets->num_rstcs; i++)
1188 __reset_control_put_internal(resets->rstc[i]);
1189 mutex_unlock(&reset_list_mutex);
1190 kfree(resets);
1191}
1192
1193/**
1194 * reset_control_put - free the reset controller
1195 * @rstc: reset controller
1196 */
1197void reset_control_put(struct reset_control *rstc)
1198{
1199 if (IS_ERR_OR_NULL(rstc))
1200 return;
1201
1202 if (reset_control_is_array(rstc)) {
1203 reset_control_array_put(rstc_to_array(rstc));
1204 return;
1205 }
1206
1207 mutex_lock(&reset_list_mutex);
1208 __reset_control_put_internal(rstc);
1209 mutex_unlock(&reset_list_mutex);
1210}
1211EXPORT_SYMBOL_GPL(reset_control_put);
1212
1213/**
1214 * reset_control_bulk_put - free the reset controllers
1215 * @num_rstcs: number of entries in rstcs array
1216 * @rstcs: array of struct reset_control_bulk_data with reset controls set
1217 */
1218void reset_control_bulk_put(int num_rstcs, struct reset_control_bulk_data *rstcs)
1219{
1220 mutex_lock(&reset_list_mutex);
1221 while (num_rstcs--)
1222 __reset_control_put_internal(rstcs[num_rstcs].rstc);
1223 mutex_unlock(&reset_list_mutex);
1224}
1225EXPORT_SYMBOL_GPL(reset_control_bulk_put);
1226
1227static void devm_reset_control_release(struct device *dev, void *res)
1228{
1229 reset_control_put(*(struct reset_control **)res);
1230}
1231
1232struct reset_control *
1233__devm_reset_control_get(struct device *dev, const char *id, int index,
1234 bool shared, bool optional, bool acquired)
1235{
1236 struct reset_control **ptr, *rstc;
1237
1238 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
1239 GFP_KERNEL);
1240 if (!ptr)
1241 return ERR_PTR(-ENOMEM);
1242
1243 rstc = __reset_control_get(dev, id, index, shared, optional, acquired);
1244 if (IS_ERR_OR_NULL(rstc)) {
1245 devres_free(ptr);
1246 return rstc;
1247 }
1248
1249 *ptr = rstc;
1250 devres_add(dev, ptr);
1251
1252 return rstc;
1253}
1254EXPORT_SYMBOL_GPL(__devm_reset_control_get);
1255
1256struct reset_control_bulk_devres {
1257 int num_rstcs;
1258 struct reset_control_bulk_data *rstcs;
1259};
1260
1261static void devm_reset_control_bulk_release(struct device *dev, void *res)
1262{
1263 struct reset_control_bulk_devres *devres = res;
1264
1265 reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
1266}
1267
1268int __devm_reset_control_bulk_get(struct device *dev, int num_rstcs,
1269 struct reset_control_bulk_data *rstcs,
1270 bool shared, bool optional, bool acquired)
1271{
1272 struct reset_control_bulk_devres *ptr;
1273 int ret;
1274
1275 ptr = devres_alloc(devm_reset_control_bulk_release, sizeof(*ptr),
1276 GFP_KERNEL);
1277 if (!ptr)
1278 return -ENOMEM;
1279
1280 ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, shared, optional, acquired);
1281 if (ret < 0) {
1282 devres_free(ptr);
1283 return ret;
1284 }
1285
1286 ptr->num_rstcs = num_rstcs;
1287 ptr->rstcs = rstcs;
1288 devres_add(dev, ptr);
1289
1290 return 0;
1291}
1292EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get);
1293
1294/**
1295 * __device_reset - find reset controller associated with the device
1296 * and perform reset
1297 * @dev: device to be reset by the controller
1298 * @optional: whether it is optional to reset the device
1299 *
1300 * Convenience wrapper for __reset_control_get() and reset_control_reset().
1301 * This is useful for the common case of devices with single, dedicated reset
1302 * lines. _RST firmware method will be called for devices with ACPI.
1303 */
1304int __device_reset(struct device *dev, bool optional)
1305{
1306 struct reset_control *rstc;
1307 int ret;
1308
1309#ifdef CONFIG_ACPI
1310 acpi_handle handle = ACPI_HANDLE(dev);
1311
1312 if (handle) {
1313 if (!acpi_has_method(handle, "_RST"))
1314 return optional ? 0 : -ENOENT;
1315 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL,
1316 NULL)))
1317 return -EIO;
1318 }
1319#endif
1320
1321 rstc = __reset_control_get(dev, NULL, 0, 0, optional, true);
1322 if (IS_ERR(rstc))
1323 return PTR_ERR(rstc);
1324
1325 ret = reset_control_reset(rstc);
1326
1327 reset_control_put(rstc);
1328
1329 return ret;
1330}
1331EXPORT_SYMBOL_GPL(__device_reset);
1332
1333/*
1334 * APIs to manage an array of reset controls.
1335 */
1336
1337/**
1338 * of_reset_control_get_count - Count number of resets available with a device
1339 *
1340 * @node: device node that contains 'resets'.
1341 *
1342 * Returns positive reset count on success, or error number on failure and
1343 * on count being zero.
1344 */
1345static int of_reset_control_get_count(struct device_node *node)
1346{
1347 int count;
1348
1349 if (!node)
1350 return -EINVAL;
1351
1352 count = of_count_phandle_with_args(node, "resets", "#reset-cells");
1353 if (count == 0)
1354 count = -ENOENT;
1355
1356 return count;
1357}
1358
1359/**
1360 * of_reset_control_array_get - Get a list of reset controls using
1361 * device node.
1362 *
1363 * @np: device node for the device that requests the reset controls array
1364 * @shared: whether reset controls are shared or not
1365 * @optional: whether it is optional to get the reset controls
1366 * @acquired: only one reset control may be acquired for a given controller
1367 * and ID
1368 *
1369 * Returns pointer to allocated reset_control on success or error on failure
1370 */
1371struct reset_control *
1372of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
1373 bool acquired)
1374{
1375 struct reset_control_array *resets;
1376 struct reset_control *rstc;
1377 int num, i;
1378
1379 num = of_reset_control_get_count(np);
1380 if (num < 0)
1381 return optional ? NULL : ERR_PTR(num);
1382
1383 resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
1384 if (!resets)
1385 return ERR_PTR(-ENOMEM);
1386 resets->num_rstcs = num;
1387
1388 for (i = 0; i < num; i++) {
1389 rstc = __of_reset_control_get(np, NULL, i, shared, optional,
1390 acquired);
1391 if (IS_ERR(rstc))
1392 goto err_rst;
1393 resets->rstc[i] = rstc;
1394 }
1395 resets->base.array = true;
1396
1397 return &resets->base;
1398
1399err_rst:
1400 mutex_lock(&reset_list_mutex);
1401 while (--i >= 0)
1402 __reset_control_put_internal(resets->rstc[i]);
1403 mutex_unlock(&reset_list_mutex);
1404
1405 kfree(resets);
1406
1407 return rstc;
1408}
1409EXPORT_SYMBOL_GPL(of_reset_control_array_get);
1410
1411/**
1412 * devm_reset_control_array_get - Resource managed reset control array get
1413 *
1414 * @dev: device that requests the list of reset controls
1415 * @shared: whether reset controls are shared or not
1416 * @optional: whether it is optional to get the reset controls
1417 *
1418 * The reset control array APIs are intended for a list of resets
1419 * that just have to be asserted or deasserted, without any
1420 * requirements on the order.
1421 *
1422 * Returns pointer to allocated reset_control on success or error on failure
1423 */
1424struct reset_control *
1425devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
1426{
1427 struct reset_control **ptr, *rstc;
1428
1429 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
1430 GFP_KERNEL);
1431 if (!ptr)
1432 return ERR_PTR(-ENOMEM);
1433
1434 rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
1435 if (IS_ERR_OR_NULL(rstc)) {
1436 devres_free(ptr);
1437 return rstc;
1438 }
1439
1440 *ptr = rstc;
1441 devres_add(dev, ptr);
1442
1443 return rstc;
1444}
1445EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
1446
1447static int reset_control_get_count_from_lookup(struct device *dev)
1448{
1449 const struct reset_control_lookup *lookup;
1450 const char *dev_id;
1451 int count = 0;
1452
1453 if (!dev)
1454 return -EINVAL;
1455
1456 dev_id = dev_name(dev);
1457 mutex_lock(&reset_lookup_mutex);
1458
1459 list_for_each_entry(lookup, &reset_lookup_list, list) {
1460 if (!strcmp(lookup->dev_id, dev_id))
1461 count++;
1462 }
1463
1464 mutex_unlock(&reset_lookup_mutex);
1465
1466 if (count == 0)
1467 count = -ENOENT;
1468
1469 return count;
1470}
1471
1472/**
1473 * reset_control_get_count - Count number of resets available with a device
1474 *
1475 * @dev: device for which to return the number of resets
1476 *
1477 * Returns positive reset count on success, or error number on failure and
1478 * on count being zero.
1479 */
1480int reset_control_get_count(struct device *dev)
1481{
1482 if (dev->of_node)
1483 return of_reset_control_get_count(dev->of_node);
1484
1485 return reset_control_get_count_from_lookup(dev);
1486}
1487EXPORT_SYMBOL_GPL(reset_control_get_count);