Commit | Line | Data |
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61fc4131 PZ |
1 | /* |
2 | * Reset Controller framework | |
3 | * | |
4 | * Copyright 2013 Philipp Zabel, Pengutronix | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
0b52297f | 11 | #include <linux/atomic.h> |
61fc4131 PZ |
12 | #include <linux/device.h> |
13 | #include <linux/err.h> | |
14 | #include <linux/export.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/of.h> | |
18 | #include <linux/reset.h> | |
19 | #include <linux/reset-controller.h> | |
20 | #include <linux/slab.h> | |
21 | ||
c15ddec2 | 22 | static DEFINE_MUTEX(reset_list_mutex); |
61fc4131 PZ |
23 | static LIST_HEAD(reset_controller_list); |
24 | ||
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 |
0b52297f HG |
33 | * @shared: Is this a shared (1), or an exclusive (0) reset_control? |
34 | * @deassert_cnt: Number of times this reset line has been deasserted | |
61fc4131 PZ |
35 | */ |
36 | struct reset_control { | |
37 | struct reset_controller_dev *rcdev; | |
c15ddec2 | 38 | struct list_head list; |
61fc4131 | 39 | unsigned int id; |
c15ddec2 | 40 | unsigned int refcnt; |
0b52297f HG |
41 | int shared; |
42 | atomic_t deassert_count; | |
61fc4131 PZ |
43 | }; |
44 | ||
45 | /** | |
46 | * of_reset_simple_xlate - translate reset_spec to the reset line number | |
47 | * @rcdev: a pointer to the reset controller device | |
48 | * @reset_spec: reset line specifier as found in the device tree | |
49 | * @flags: a flags pointer to fill in (optional) | |
50 | * | |
51 | * This simple translation function should be used for reset controllers | |
52 | * with 1:1 mapping, where reset lines can be indexed by number without gaps. | |
53 | */ | |
0c5b2b91 | 54 | static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, |
61fc4131 PZ |
55 | const struct of_phandle_args *reset_spec) |
56 | { | |
61fc4131 PZ |
57 | if (reset_spec->args[0] >= rcdev->nr_resets) |
58 | return -EINVAL; | |
59 | ||
60 | return reset_spec->args[0]; | |
61 | } | |
61fc4131 PZ |
62 | |
63 | /** | |
64 | * reset_controller_register - register a reset controller device | |
65 | * @rcdev: a pointer to the initialized reset controller device | |
66 | */ | |
67 | int reset_controller_register(struct reset_controller_dev *rcdev) | |
68 | { | |
69 | if (!rcdev->of_xlate) { | |
70 | rcdev->of_reset_n_cells = 1; | |
71 | rcdev->of_xlate = of_reset_simple_xlate; | |
72 | } | |
73 | ||
c15ddec2 HG |
74 | INIT_LIST_HEAD(&rcdev->reset_control_head); |
75 | ||
76 | mutex_lock(&reset_list_mutex); | |
61fc4131 | 77 | list_add(&rcdev->list, &reset_controller_list); |
c15ddec2 | 78 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
79 | |
80 | return 0; | |
81 | } | |
82 | EXPORT_SYMBOL_GPL(reset_controller_register); | |
83 | ||
84 | /** | |
85 | * reset_controller_unregister - unregister a reset controller device | |
86 | * @rcdev: a pointer to the reset controller device | |
87 | */ | |
88 | void reset_controller_unregister(struct reset_controller_dev *rcdev) | |
89 | { | |
c15ddec2 | 90 | mutex_lock(&reset_list_mutex); |
61fc4131 | 91 | list_del(&rcdev->list); |
c15ddec2 | 92 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
93 | } |
94 | EXPORT_SYMBOL_GPL(reset_controller_unregister); | |
95 | ||
8d5b5d5c MY |
96 | static void devm_reset_controller_release(struct device *dev, void *res) |
97 | { | |
98 | reset_controller_unregister(*(struct reset_controller_dev **)res); | |
99 | } | |
100 | ||
101 | /** | |
102 | * devm_reset_controller_register - resource managed reset_controller_register() | |
103 | * @dev: device that is registering this reset controller | |
104 | * @rcdev: a pointer to the initialized reset controller device | |
105 | * | |
106 | * Managed reset_controller_register(). For reset controllers registered by | |
107 | * this function, reset_controller_unregister() is automatically called on | |
108 | * driver detach. See reset_controller_register() for more information. | |
109 | */ | |
110 | int devm_reset_controller_register(struct device *dev, | |
111 | struct reset_controller_dev *rcdev) | |
112 | { | |
113 | struct reset_controller_dev **rcdevp; | |
114 | int ret; | |
115 | ||
116 | rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp), | |
117 | GFP_KERNEL); | |
118 | if (!rcdevp) | |
119 | return -ENOMEM; | |
120 | ||
121 | ret = reset_controller_register(rcdev); | |
122 | if (!ret) { | |
123 | *rcdevp = rcdev; | |
124 | devres_add(dev, rcdevp); | |
125 | } else { | |
126 | devres_free(rcdevp); | |
127 | } | |
128 | ||
129 | return ret; | |
130 | } | |
131 | EXPORT_SYMBOL_GPL(devm_reset_controller_register); | |
132 | ||
61fc4131 PZ |
133 | /** |
134 | * reset_control_reset - reset the controlled device | |
135 | * @rstc: reset controller | |
0b52297f HG |
136 | * |
137 | * Calling this on a shared reset controller is an error. | |
61fc4131 PZ |
138 | */ |
139 | int reset_control_reset(struct reset_control *rstc) | |
140 | { | |
a3774e14 PZ |
141 | if (WARN_ON(IS_ERR_OR_NULL(rstc)) || |
142 | WARN_ON(rstc->shared)) | |
0b52297f HG |
143 | return -EINVAL; |
144 | ||
61fc4131 PZ |
145 | if (rstc->rcdev->ops->reset) |
146 | return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); | |
147 | ||
39b4da71 | 148 | return -ENOTSUPP; |
61fc4131 PZ |
149 | } |
150 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
151 | ||
152 | /** | |
153 | * reset_control_assert - asserts the reset line | |
154 | * @rstc: reset controller | |
0b52297f HG |
155 | * |
156 | * Calling this on an exclusive reset controller guarantees that the reset | |
157 | * will be asserted. When called on a shared reset controller the line may | |
158 | * still be deasserted, as long as other users keep it so. | |
159 | * | |
160 | * For shared reset controls a driver cannot expect the hw's registers and | |
161 | * internal state to be reset, but must be prepared for this to happen. | |
61fc4131 PZ |
162 | */ |
163 | int reset_control_assert(struct reset_control *rstc) | |
164 | { | |
a3774e14 PZ |
165 | if (WARN_ON(IS_ERR_OR_NULL(rstc))) |
166 | return -EINVAL; | |
167 | ||
0b52297f HG |
168 | if (!rstc->rcdev->ops->assert) |
169 | return -ENOTSUPP; | |
61fc4131 | 170 | |
0b52297f HG |
171 | if (rstc->shared) { |
172 | if (WARN_ON(atomic_read(&rstc->deassert_count) == 0)) | |
173 | return -EINVAL; | |
174 | ||
175 | if (atomic_dec_return(&rstc->deassert_count) != 0) | |
176 | return 0; | |
177 | } | |
178 | ||
179 | return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); | |
61fc4131 PZ |
180 | } |
181 | EXPORT_SYMBOL_GPL(reset_control_assert); | |
182 | ||
183 | /** | |
184 | * reset_control_deassert - deasserts the reset line | |
185 | * @rstc: reset controller | |
0b52297f HG |
186 | * |
187 | * After calling this function, the reset is guaranteed to be deasserted. | |
61fc4131 PZ |
188 | */ |
189 | int reset_control_deassert(struct reset_control *rstc) | |
190 | { | |
a3774e14 PZ |
191 | if (WARN_ON(IS_ERR_OR_NULL(rstc))) |
192 | return -EINVAL; | |
193 | ||
0b52297f HG |
194 | if (!rstc->rcdev->ops->deassert) |
195 | return -ENOTSUPP; | |
61fc4131 | 196 | |
0b52297f HG |
197 | if (rstc->shared) { |
198 | if (atomic_inc_return(&rstc->deassert_count) != 1) | |
199 | return 0; | |
200 | } | |
201 | ||
202 | return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); | |
61fc4131 PZ |
203 | } |
204 | EXPORT_SYMBOL_GPL(reset_control_deassert); | |
205 | ||
729de41b DN |
206 | /** |
207 | * reset_control_status - returns a negative errno if not supported, a | |
208 | * positive value if the reset line is asserted, or zero if the reset | |
209 | * line is not asserted. | |
210 | * @rstc: reset controller | |
211 | */ | |
212 | int reset_control_status(struct reset_control *rstc) | |
213 | { | |
a3774e14 PZ |
214 | if (WARN_ON(IS_ERR_OR_NULL(rstc))) |
215 | return -EINVAL; | |
216 | ||
729de41b DN |
217 | if (rstc->rcdev->ops->status) |
218 | return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); | |
219 | ||
39b4da71 | 220 | return -ENOTSUPP; |
729de41b DN |
221 | } |
222 | EXPORT_SYMBOL_GPL(reset_control_status); | |
223 | ||
c15ddec2 HG |
224 | static struct reset_control *__reset_control_get( |
225 | struct reset_controller_dev *rcdev, | |
0b52297f | 226 | unsigned int index, int shared) |
c15ddec2 HG |
227 | { |
228 | struct reset_control *rstc; | |
229 | ||
230 | lockdep_assert_held(&reset_list_mutex); | |
231 | ||
232 | list_for_each_entry(rstc, &rcdev->reset_control_head, list) { | |
233 | if (rstc->id == index) { | |
0b52297f HG |
234 | if (WARN_ON(!rstc->shared || !shared)) |
235 | return ERR_PTR(-EBUSY); | |
236 | ||
c15ddec2 HG |
237 | rstc->refcnt++; |
238 | return rstc; | |
239 | } | |
240 | } | |
241 | ||
242 | rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); | |
243 | if (!rstc) | |
244 | return ERR_PTR(-ENOMEM); | |
245 | ||
246 | try_module_get(rcdev->owner); | |
247 | ||
248 | rstc->rcdev = rcdev; | |
249 | list_add(&rstc->list, &rcdev->reset_control_head); | |
250 | rstc->id = index; | |
251 | rstc->refcnt = 1; | |
0b52297f | 252 | rstc->shared = shared; |
c15ddec2 HG |
253 | |
254 | return rstc; | |
255 | } | |
256 | ||
257 | static void __reset_control_put(struct reset_control *rstc) | |
258 | { | |
259 | lockdep_assert_held(&reset_list_mutex); | |
260 | ||
261 | if (--rstc->refcnt) | |
262 | return; | |
263 | ||
264 | module_put(rstc->rcdev->owner); | |
265 | ||
266 | list_del(&rstc->list); | |
267 | kfree(rstc); | |
268 | } | |
269 | ||
6c96f05c | 270 | struct reset_control *__of_reset_control_get(struct device_node *node, |
0b52297f | 271 | const char *id, int index, int shared) |
61fc4131 | 272 | { |
d056c9b8 | 273 | struct reset_control *rstc; |
61fc4131 PZ |
274 | struct reset_controller_dev *r, *rcdev; |
275 | struct of_phandle_args args; | |
61fc4131 PZ |
276 | int rstc_id; |
277 | int ret; | |
278 | ||
6c96f05c HG |
279 | if (!node) |
280 | return ERR_PTR(-EINVAL); | |
281 | ||
282 | if (id) { | |
283 | index = of_property_match_string(node, | |
284 | "reset-names", id); | |
285 | if (index < 0) | |
286 | return ERR_PTR(-ENOENT); | |
287 | } | |
288 | ||
fc0a5921 | 289 | ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
61fc4131 PZ |
290 | index, &args); |
291 | if (ret) | |
292 | return ERR_PTR(ret); | |
293 | ||
c15ddec2 | 294 | mutex_lock(&reset_list_mutex); |
61fc4131 PZ |
295 | rcdev = NULL; |
296 | list_for_each_entry(r, &reset_controller_list, list) { | |
297 | if (args.np == r->of_node) { | |
298 | rcdev = r; | |
299 | break; | |
300 | } | |
301 | } | |
302 | of_node_put(args.np); | |
303 | ||
304 | if (!rcdev) { | |
c15ddec2 | 305 | mutex_unlock(&reset_list_mutex); |
3d103020 | 306 | return ERR_PTR(-EPROBE_DEFER); |
61fc4131 PZ |
307 | } |
308 | ||
e677774f | 309 | if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { |
c15ddec2 | 310 | mutex_unlock(&reset_list_mutex); |
e677774f MR |
311 | return ERR_PTR(-EINVAL); |
312 | } | |
313 | ||
61fc4131 PZ |
314 | rstc_id = rcdev->of_xlate(rcdev, &args); |
315 | if (rstc_id < 0) { | |
c15ddec2 | 316 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
317 | return ERR_PTR(rstc_id); |
318 | } | |
319 | ||
c15ddec2 | 320 | /* reset_list_mutex also protects the rcdev's reset_control list */ |
0b52297f | 321 | rstc = __reset_control_get(rcdev, rstc_id, shared); |
61fc4131 | 322 | |
c15ddec2 | 323 | mutex_unlock(&reset_list_mutex); |
61fc4131 PZ |
324 | |
325 | return rstc; | |
326 | } | |
6c96f05c | 327 | EXPORT_SYMBOL_GPL(__of_reset_control_get); |
61fc4131 PZ |
328 | |
329 | /** | |
330 | * reset_control_put - free the reset controller | |
331 | * @rstc: reset controller | |
332 | */ | |
333 | ||
334 | void reset_control_put(struct reset_control *rstc) | |
335 | { | |
336 | if (IS_ERR(rstc)) | |
337 | return; | |
338 | ||
c15ddec2 HG |
339 | mutex_lock(&reset_list_mutex); |
340 | __reset_control_put(rstc); | |
341 | mutex_unlock(&reset_list_mutex); | |
61fc4131 PZ |
342 | } |
343 | EXPORT_SYMBOL_GPL(reset_control_put); | |
344 | ||
345 | static void devm_reset_control_release(struct device *dev, void *res) | |
346 | { | |
347 | reset_control_put(*(struct reset_control **)res); | |
348 | } | |
349 | ||
6c96f05c | 350 | struct reset_control *__devm_reset_control_get(struct device *dev, |
0b52297f | 351 | const char *id, int index, int shared) |
61fc4131 PZ |
352 | { |
353 | struct reset_control **ptr, *rstc; | |
354 | ||
355 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
356 | GFP_KERNEL); | |
357 | if (!ptr) | |
358 | return ERR_PTR(-ENOMEM); | |
359 | ||
0b52297f HG |
360 | rstc = __of_reset_control_get(dev ? dev->of_node : NULL, |
361 | id, index, shared); | |
61fc4131 PZ |
362 | if (!IS_ERR(rstc)) { |
363 | *ptr = rstc; | |
364 | devres_add(dev, ptr); | |
365 | } else { | |
366 | devres_free(ptr); | |
367 | } | |
368 | ||
369 | return rstc; | |
370 | } | |
6c96f05c | 371 | EXPORT_SYMBOL_GPL(__devm_reset_control_get); |
61fc4131 | 372 | |
61fc4131 PZ |
373 | /** |
374 | * device_reset - find reset controller associated with the device | |
375 | * and perform reset | |
376 | * @dev: device to be reset by the controller | |
377 | * | |
378 | * Convenience wrapper for reset_control_get() and reset_control_reset(). | |
379 | * This is useful for the common case of devices with single, dedicated reset | |
380 | * lines. | |
381 | */ | |
382 | int device_reset(struct device *dev) | |
383 | { | |
384 | struct reset_control *rstc; | |
385 | int ret; | |
386 | ||
387 | rstc = reset_control_get(dev, NULL); | |
388 | if (IS_ERR(rstc)) | |
389 | return PTR_ERR(rstc); | |
390 | ||
391 | ret = reset_control_reset(rstc); | |
392 | ||
393 | reset_control_put(rstc); | |
394 | ||
395 | return ret; | |
396 | } | |
397 | EXPORT_SYMBOL_GPL(device_reset); |