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e1f60b29 NM |
1 | /* |
2 | * Generic OPP Interface | |
3 | * | |
4 | * Copyright (C) 2009-2010 Texas Instruments Incorporated. | |
5 | * Nishanth Menon | |
6 | * Romit Dasgupta | |
7 | * Kevin Hilman | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/err.h> | |
e1f60b29 | 17 | #include <linux/slab.h> |
51990e82 | 18 | #include <linux/device.h> |
e1f60b29 NM |
19 | #include <linux/list.h> |
20 | #include <linux/rculist.h> | |
21 | #include <linux/rcupdate.h> | |
e4db1c74 | 22 | #include <linux/pm_opp.h> |
b496dfbc | 23 | #include <linux/of.h> |
80126ce7 | 24 | #include <linux/export.h> |
e1f60b29 NM |
25 | |
26 | /* | |
27 | * Internal data structure organization with the OPP layer library is as | |
28 | * follows: | |
29 | * dev_opp_list (root) | |
30 | * |- device 1 (represents voltage domain 1) | |
31 | * | |- opp 1 (availability, freq, voltage) | |
32 | * | |- opp 2 .. | |
33 | * ... ... | |
34 | * | `- opp n .. | |
35 | * |- device 2 (represents the next voltage domain) | |
36 | * ... | |
37 | * `- device m (represents mth voltage domain) | |
38 | * device 1, 2.. are represented by dev_opp structure while each opp | |
39 | * is represented by the opp structure. | |
40 | */ | |
41 | ||
42 | /** | |
47d43ba7 | 43 | * struct dev_pm_opp - Generic OPP description structure |
e1f60b29 NM |
44 | * @node: opp list node. The nodes are maintained throughout the lifetime |
45 | * of boot. It is expected only an optimal set of OPPs are | |
46 | * added to the library by the SoC framework. | |
47 | * RCU usage: opp list is traversed with RCU locks. node | |
48 | * modification is possible realtime, hence the modifications | |
49 | * are protected by the dev_opp_list_lock for integrity. | |
50 | * IMPORTANT: the opp nodes should be maintained in increasing | |
51 | * order. | |
38393409 | 52 | * @dynamic: not-created from static DT entries. |
e1f60b29 NM |
53 | * @available: true/false - marks if this OPP as available or not |
54 | * @rate: Frequency in hertz | |
55 | * @u_volt: Nominal voltage in microvolts corresponding to this OPP | |
56 | * @dev_opp: points back to the device_opp struct this opp belongs to | |
cd1a068a | 57 | * @rcu_head: RCU callback head used for deferred freeing |
e1f60b29 NM |
58 | * |
59 | * This structure stores the OPP information for a given device. | |
60 | */ | |
47d43ba7 | 61 | struct dev_pm_opp { |
e1f60b29 NM |
62 | struct list_head node; |
63 | ||
64 | bool available; | |
38393409 | 65 | bool dynamic; |
e1f60b29 NM |
66 | unsigned long rate; |
67 | unsigned long u_volt; | |
68 | ||
69 | struct device_opp *dev_opp; | |
cd1a068a | 70 | struct rcu_head rcu_head; |
e1f60b29 NM |
71 | }; |
72 | ||
73 | /** | |
74 | * struct device_opp - Device opp structure | |
75 | * @node: list node - contains the devices with OPPs that | |
76 | * have been registered. Nodes once added are not modified in this | |
77 | * list. | |
78 | * RCU usage: nodes are not modified in the list of device_opp, | |
79 | * however addition is possible and is secured by dev_opp_list_lock | |
80 | * @dev: device pointer | |
cd1a068a | 81 | * @srcu_head: notifier head to notify the OPP availability changes. |
129eec55 | 82 | * @rcu_head: RCU callback head used for deferred freeing |
e1f60b29 NM |
83 | * @opp_list: list of opps |
84 | * | |
85 | * This is an internal data structure maintaining the link to opps attached to | |
86 | * a device. This structure is not meant to be shared to users as it is | |
1c6a662f VK |
87 | * meant for book keeping and private to OPP library. |
88 | * | |
89 | * Because the opp structures can be used from both rcu and srcu readers, we | |
90 | * need to wait for the grace period of both of them before freeing any | |
91 | * resources. And so we have used kfree_rcu() from within call_srcu() handlers. | |
e1f60b29 NM |
92 | */ |
93 | struct device_opp { | |
94 | struct list_head node; | |
95 | ||
96 | struct device *dev; | |
cd1a068a | 97 | struct srcu_notifier_head srcu_head; |
129eec55 | 98 | struct rcu_head rcu_head; |
e1f60b29 NM |
99 | struct list_head opp_list; |
100 | }; | |
101 | ||
102 | /* | |
103 | * The root of the list of all devices. All device_opp structures branch off | |
104 | * from here, with each device_opp containing the list of opp it supports in | |
105 | * various states of availability. | |
106 | */ | |
107 | static LIST_HEAD(dev_opp_list); | |
108 | /* Lock to allow exclusive modification to the device and opp lists */ | |
109 | static DEFINE_MUTEX(dev_opp_list_lock); | |
110 | ||
b02ded24 DT |
111 | #define opp_rcu_lockdep_assert() \ |
112 | do { \ | |
113 | rcu_lockdep_assert(rcu_read_lock_held() || \ | |
114 | lockdep_is_held(&dev_opp_list_lock), \ | |
115 | "Missing rcu_read_lock() or " \ | |
116 | "dev_opp_list_lock protection"); \ | |
117 | } while (0) | |
118 | ||
e1f60b29 NM |
119 | /** |
120 | * find_device_opp() - find device_opp struct using device pointer | |
121 | * @dev: device pointer used to lookup device OPPs | |
122 | * | |
123 | * Search list of device OPPs for one containing matching device. Does a RCU | |
124 | * reader operation to grab the pointer needed. | |
125 | * | |
126 | * Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or | |
127 | * -EINVAL based on type of error. | |
128 | * | |
129 | * Locking: This function must be called under rcu_read_lock(). device_opp | |
130 | * is a RCU protected pointer. This means that device_opp is valid as long | |
131 | * as we are under RCU lock. | |
132 | */ | |
133 | static struct device_opp *find_device_opp(struct device *dev) | |
134 | { | |
135 | struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV); | |
136 | ||
137 | if (unlikely(IS_ERR_OR_NULL(dev))) { | |
138 | pr_err("%s: Invalid parameters\n", __func__); | |
139 | return ERR_PTR(-EINVAL); | |
140 | } | |
141 | ||
142 | list_for_each_entry_rcu(tmp_dev_opp, &dev_opp_list, node) { | |
143 | if (tmp_dev_opp->dev == dev) { | |
144 | dev_opp = tmp_dev_opp; | |
145 | break; | |
146 | } | |
147 | } | |
148 | ||
149 | return dev_opp; | |
150 | } | |
151 | ||
152 | /** | |
5d4879cd | 153 | * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp |
e1f60b29 NM |
154 | * @opp: opp for which voltage has to be returned for |
155 | * | |
156 | * Return voltage in micro volt corresponding to the opp, else | |
157 | * return 0 | |
158 | * | |
159 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
160 | * protected pointer. This means that opp which could have been fetched by | |
161 | * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are | |
162 | * under RCU lock. The pointer returned by the opp_find_freq family must be | |
163 | * used in the same section as the usage of this function with the pointer | |
164 | * prior to unlocking with rcu_read_unlock() to maintain the integrity of the | |
165 | * pointer. | |
166 | */ | |
47d43ba7 | 167 | unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp) |
e1f60b29 | 168 | { |
47d43ba7 | 169 | struct dev_pm_opp *tmp_opp; |
e1f60b29 NM |
170 | unsigned long v = 0; |
171 | ||
172 | tmp_opp = rcu_dereference(opp); | |
173 | if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) | |
174 | pr_err("%s: Invalid parameters\n", __func__); | |
175 | else | |
176 | v = tmp_opp->u_volt; | |
177 | ||
178 | return v; | |
179 | } | |
5d4879cd | 180 | EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage); |
e1f60b29 NM |
181 | |
182 | /** | |
5d4879cd | 183 | * dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp |
e1f60b29 NM |
184 | * @opp: opp for which frequency has to be returned for |
185 | * | |
186 | * Return frequency in hertz corresponding to the opp, else | |
187 | * return 0 | |
188 | * | |
189 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
190 | * protected pointer. This means that opp which could have been fetched by | |
191 | * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are | |
192 | * under RCU lock. The pointer returned by the opp_find_freq family must be | |
193 | * used in the same section as the usage of this function with the pointer | |
194 | * prior to unlocking with rcu_read_unlock() to maintain the integrity of the | |
195 | * pointer. | |
196 | */ | |
47d43ba7 | 197 | unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp) |
e1f60b29 | 198 | { |
47d43ba7 | 199 | struct dev_pm_opp *tmp_opp; |
e1f60b29 NM |
200 | unsigned long f = 0; |
201 | ||
202 | tmp_opp = rcu_dereference(opp); | |
203 | if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) | |
204 | pr_err("%s: Invalid parameters\n", __func__); | |
205 | else | |
206 | f = tmp_opp->rate; | |
207 | ||
208 | return f; | |
209 | } | |
5d4879cd | 210 | EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq); |
e1f60b29 NM |
211 | |
212 | /** | |
5d4879cd | 213 | * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list |
e1f60b29 NM |
214 | * @dev: device for which we do this operation |
215 | * | |
216 | * This function returns the number of available opps if there are any, | |
217 | * else returns 0 if none or the corresponding error value. | |
218 | * | |
b4718c02 | 219 | * Locking: This function takes rcu_read_lock(). |
e1f60b29 | 220 | */ |
5d4879cd | 221 | int dev_pm_opp_get_opp_count(struct device *dev) |
e1f60b29 NM |
222 | { |
223 | struct device_opp *dev_opp; | |
47d43ba7 | 224 | struct dev_pm_opp *temp_opp; |
e1f60b29 NM |
225 | int count = 0; |
226 | ||
b4718c02 | 227 | rcu_read_lock(); |
b02ded24 | 228 | |
e1f60b29 NM |
229 | dev_opp = find_device_opp(dev); |
230 | if (IS_ERR(dev_opp)) { | |
b4718c02 DT |
231 | count = PTR_ERR(dev_opp); |
232 | dev_err(dev, "%s: device OPP not found (%d)\n", | |
233 | __func__, count); | |
234 | goto out_unlock; | |
e1f60b29 NM |
235 | } |
236 | ||
237 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
238 | if (temp_opp->available) | |
239 | count++; | |
240 | } | |
241 | ||
b4718c02 DT |
242 | out_unlock: |
243 | rcu_read_unlock(); | |
e1f60b29 NM |
244 | return count; |
245 | } | |
5d4879cd | 246 | EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count); |
e1f60b29 NM |
247 | |
248 | /** | |
5d4879cd | 249 | * dev_pm_opp_find_freq_exact() - search for an exact frequency |
e1f60b29 NM |
250 | * @dev: device for which we do this operation |
251 | * @freq: frequency to search for | |
7ae49618 | 252 | * @available: true/false - match for available opp |
e1f60b29 NM |
253 | * |
254 | * Searches for exact match in the opp list and returns pointer to the matching | |
255 | * opp if found, else returns ERR_PTR in case of error and should be handled | |
0779726c NM |
256 | * using IS_ERR. Error return values can be: |
257 | * EINVAL: for bad pointer | |
258 | * ERANGE: no match found for search | |
259 | * ENODEV: if device not found in list of registered devices | |
e1f60b29 NM |
260 | * |
261 | * Note: available is a modifier for the search. if available=true, then the | |
262 | * match is for exact matching frequency and is available in the stored OPP | |
263 | * table. if false, the match is for exact frequency which is not available. | |
264 | * | |
265 | * This provides a mechanism to enable an opp which is not available currently | |
266 | * or the opposite as well. | |
267 | * | |
268 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
269 | * protected pointer. The reason for the same is that the opp pointer which is | |
270 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
271 | * under the locked area. The pointer returned must be used prior to unlocking | |
272 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
273 | */ | |
47d43ba7 NM |
274 | struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, |
275 | unsigned long freq, | |
276 | bool available) | |
e1f60b29 NM |
277 | { |
278 | struct device_opp *dev_opp; | |
47d43ba7 | 279 | struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
e1f60b29 | 280 | |
b02ded24 DT |
281 | opp_rcu_lockdep_assert(); |
282 | ||
e1f60b29 NM |
283 | dev_opp = find_device_opp(dev); |
284 | if (IS_ERR(dev_opp)) { | |
285 | int r = PTR_ERR(dev_opp); | |
286 | dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r); | |
287 | return ERR_PTR(r); | |
288 | } | |
289 | ||
290 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
291 | if (temp_opp->available == available && | |
292 | temp_opp->rate == freq) { | |
293 | opp = temp_opp; | |
294 | break; | |
295 | } | |
296 | } | |
297 | ||
298 | return opp; | |
299 | } | |
5d4879cd | 300 | EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact); |
e1f60b29 NM |
301 | |
302 | /** | |
5d4879cd | 303 | * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq |
e1f60b29 NM |
304 | * @dev: device for which we do this operation |
305 | * @freq: Start frequency | |
306 | * | |
307 | * Search for the matching ceil *available* OPP from a starting freq | |
308 | * for a device. | |
309 | * | |
310 | * Returns matching *opp and refreshes *freq accordingly, else returns | |
0779726c NM |
311 | * ERR_PTR in case of error and should be handled using IS_ERR. Error return |
312 | * values can be: | |
313 | * EINVAL: for bad pointer | |
314 | * ERANGE: no match found for search | |
315 | * ENODEV: if device not found in list of registered devices | |
e1f60b29 NM |
316 | * |
317 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
318 | * protected pointer. The reason for the same is that the opp pointer which is | |
319 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
320 | * under the locked area. The pointer returned must be used prior to unlocking | |
321 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
322 | */ | |
47d43ba7 NM |
323 | struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev, |
324 | unsigned long *freq) | |
e1f60b29 NM |
325 | { |
326 | struct device_opp *dev_opp; | |
47d43ba7 | 327 | struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
e1f60b29 | 328 | |
b02ded24 DT |
329 | opp_rcu_lockdep_assert(); |
330 | ||
e1f60b29 NM |
331 | if (!dev || !freq) { |
332 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); | |
333 | return ERR_PTR(-EINVAL); | |
334 | } | |
335 | ||
336 | dev_opp = find_device_opp(dev); | |
337 | if (IS_ERR(dev_opp)) | |
0779726c | 338 | return ERR_CAST(dev_opp); |
e1f60b29 NM |
339 | |
340 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
341 | if (temp_opp->available && temp_opp->rate >= *freq) { | |
342 | opp = temp_opp; | |
343 | *freq = opp->rate; | |
344 | break; | |
345 | } | |
346 | } | |
347 | ||
348 | return opp; | |
349 | } | |
5d4879cd | 350 | EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil); |
e1f60b29 NM |
351 | |
352 | /** | |
5d4879cd | 353 | * dev_pm_opp_find_freq_floor() - Search for a rounded floor freq |
e1f60b29 NM |
354 | * @dev: device for which we do this operation |
355 | * @freq: Start frequency | |
356 | * | |
357 | * Search for the matching floor *available* OPP from a starting freq | |
358 | * for a device. | |
359 | * | |
360 | * Returns matching *opp and refreshes *freq accordingly, else returns | |
0779726c NM |
361 | * ERR_PTR in case of error and should be handled using IS_ERR. Error return |
362 | * values can be: | |
363 | * EINVAL: for bad pointer | |
364 | * ERANGE: no match found for search | |
365 | * ENODEV: if device not found in list of registered devices | |
e1f60b29 NM |
366 | * |
367 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
368 | * protected pointer. The reason for the same is that the opp pointer which is | |
369 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
370 | * under the locked area. The pointer returned must be used prior to unlocking | |
371 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
372 | */ | |
47d43ba7 NM |
373 | struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, |
374 | unsigned long *freq) | |
e1f60b29 NM |
375 | { |
376 | struct device_opp *dev_opp; | |
47d43ba7 | 377 | struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
e1f60b29 | 378 | |
b02ded24 DT |
379 | opp_rcu_lockdep_assert(); |
380 | ||
e1f60b29 NM |
381 | if (!dev || !freq) { |
382 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); | |
383 | return ERR_PTR(-EINVAL); | |
384 | } | |
385 | ||
386 | dev_opp = find_device_opp(dev); | |
387 | if (IS_ERR(dev_opp)) | |
0779726c | 388 | return ERR_CAST(dev_opp); |
e1f60b29 NM |
389 | |
390 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
391 | if (temp_opp->available) { | |
392 | /* go to the next node, before choosing prev */ | |
393 | if (temp_opp->rate > *freq) | |
394 | break; | |
395 | else | |
396 | opp = temp_opp; | |
397 | } | |
398 | } | |
399 | if (!IS_ERR(opp)) | |
400 | *freq = opp->rate; | |
401 | ||
402 | return opp; | |
403 | } | |
5d4879cd | 404 | EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor); |
e1f60b29 | 405 | |
07cce74a VK |
406 | static struct device_opp *add_device_opp(struct device *dev) |
407 | { | |
408 | struct device_opp *dev_opp; | |
409 | ||
410 | /* | |
411 | * Allocate a new device OPP table. In the infrequent case where a new | |
412 | * device is needed to be added, we pay this penalty. | |
413 | */ | |
414 | dev_opp = kzalloc(sizeof(*dev_opp), GFP_KERNEL); | |
415 | if (!dev_opp) | |
416 | return NULL; | |
417 | ||
418 | dev_opp->dev = dev; | |
419 | srcu_init_notifier_head(&dev_opp->srcu_head); | |
420 | INIT_LIST_HEAD(&dev_opp->opp_list); | |
421 | ||
422 | /* Secure the device list modification */ | |
423 | list_add_rcu(&dev_opp->node, &dev_opp_list); | |
424 | return dev_opp; | |
425 | } | |
426 | ||
38393409 VK |
427 | static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq, |
428 | unsigned long u_volt, bool dynamic) | |
e1f60b29 NM |
429 | { |
430 | struct device_opp *dev_opp = NULL; | |
47d43ba7 | 431 | struct dev_pm_opp *opp, *new_opp; |
e1f60b29 | 432 | struct list_head *head; |
6ce4184d | 433 | int ret; |
e1f60b29 NM |
434 | |
435 | /* allocate new OPP node */ | |
47d43ba7 | 436 | new_opp = kzalloc(sizeof(*new_opp), GFP_KERNEL); |
e1f60b29 NM |
437 | if (!new_opp) { |
438 | dev_warn(dev, "%s: Unable to create new OPP node\n", __func__); | |
439 | return -ENOMEM; | |
440 | } | |
441 | ||
442 | /* Hold our list modification lock here */ | |
443 | mutex_lock(&dev_opp_list_lock); | |
444 | ||
a7470db6 | 445 | /* populate the opp table */ |
a7470db6 VK |
446 | new_opp->rate = freq; |
447 | new_opp->u_volt = u_volt; | |
448 | new_opp->available = true; | |
38393409 | 449 | new_opp->dynamic = dynamic; |
a7470db6 | 450 | |
e1f60b29 NM |
451 | /* Check for existing list for 'dev' */ |
452 | dev_opp = find_device_opp(dev); | |
453 | if (IS_ERR(dev_opp)) { | |
07cce74a | 454 | dev_opp = add_device_opp(dev); |
e1f60b29 | 455 | if (!dev_opp) { |
6ce4184d VK |
456 | ret = -ENOMEM; |
457 | goto free_opp; | |
e1f60b29 NM |
458 | } |
459 | ||
a7470db6 VK |
460 | head = &dev_opp->opp_list; |
461 | goto list_add; | |
e1f60b29 NM |
462 | } |
463 | ||
64ce8545 CK |
464 | /* |
465 | * Insert new OPP in order of increasing frequency | |
466 | * and discard if already present | |
467 | */ | |
e1f60b29 NM |
468 | head = &dev_opp->opp_list; |
469 | list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) { | |
64ce8545 | 470 | if (new_opp->rate <= opp->rate) |
e1f60b29 NM |
471 | break; |
472 | else | |
473 | head = &opp->node; | |
474 | } | |
475 | ||
64ce8545 CK |
476 | /* Duplicate OPPs ? */ |
477 | if (new_opp->rate == opp->rate) { | |
6ce4184d | 478 | ret = opp->available && new_opp->u_volt == opp->u_volt ? |
64ce8545 CK |
479 | 0 : -EEXIST; |
480 | ||
481 | dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n", | |
482 | __func__, opp->rate, opp->u_volt, opp->available, | |
483 | new_opp->rate, new_opp->u_volt, new_opp->available); | |
6ce4184d | 484 | goto free_opp; |
64ce8545 CK |
485 | } |
486 | ||
a7470db6 | 487 | list_add: |
7284a00f | 488 | new_opp->dev_opp = dev_opp; |
e1f60b29 NM |
489 | list_add_rcu(&new_opp->node, head); |
490 | mutex_unlock(&dev_opp_list_lock); | |
491 | ||
03ca370f MH |
492 | /* |
493 | * Notify the changes in the availability of the operable | |
494 | * frequency/voltage list. | |
495 | */ | |
cd1a068a | 496 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp); |
e1f60b29 | 497 | return 0; |
6ce4184d VK |
498 | |
499 | free_opp: | |
500 | mutex_unlock(&dev_opp_list_lock); | |
501 | kfree(new_opp); | |
502 | return ret; | |
e1f60b29 | 503 | } |
38393409 VK |
504 | |
505 | /** | |
506 | * dev_pm_opp_add() - Add an OPP table from a table definitions | |
507 | * @dev: device for which we do this operation | |
508 | * @freq: Frequency in Hz for this OPP | |
509 | * @u_volt: Voltage in uVolts for this OPP | |
510 | * | |
511 | * This function adds an opp definition to the opp list and returns status. | |
512 | * The opp is made available by default and it can be controlled using | |
513 | * dev_pm_opp_enable/disable functions. | |
514 | * | |
515 | * Locking: The internal device_opp and opp structures are RCU protected. | |
516 | * Hence this function internally uses RCU updater strategy with mutex locks | |
517 | * to keep the integrity of the internal data structures. Callers should ensure | |
518 | * that this function is *NOT* called under RCU protection or in contexts where | |
519 | * mutex cannot be locked. | |
520 | * | |
521 | * Return: | |
522 | * 0: On success OR | |
523 | * Duplicate OPPs (both freq and volt are same) and opp->available | |
524 | * -EEXIST: Freq are same and volt are different OR | |
525 | * Duplicate OPPs (both freq and volt are same) and !opp->available | |
526 | * -ENOMEM: Memory allocation failure | |
527 | */ | |
528 | int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) | |
529 | { | |
530 | return dev_pm_opp_add_dynamic(dev, freq, u_volt, true); | |
531 | } | |
5d4879cd | 532 | EXPORT_SYMBOL_GPL(dev_pm_opp_add); |
e1f60b29 | 533 | |
129eec55 VK |
534 | static void kfree_opp_rcu(struct rcu_head *head) |
535 | { | |
536 | struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head); | |
537 | ||
538 | kfree_rcu(opp, rcu_head); | |
539 | } | |
540 | ||
541 | static void kfree_device_rcu(struct rcu_head *head) | |
542 | { | |
543 | struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head); | |
544 | ||
1c6a662f | 545 | kfree_rcu(device_opp, rcu_head); |
129eec55 VK |
546 | } |
547 | ||
86453b47 VK |
548 | static void __dev_pm_opp_remove(struct device_opp *dev_opp, |
549 | struct dev_pm_opp *opp) | |
129eec55 VK |
550 | { |
551 | /* | |
552 | * Notify the changes in the availability of the operable | |
553 | * frequency/voltage list. | |
554 | */ | |
555 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp); | |
556 | list_del_rcu(&opp->node); | |
557 | call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu); | |
558 | ||
559 | if (list_empty(&dev_opp->opp_list)) { | |
560 | list_del_rcu(&dev_opp->node); | |
561 | call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head, | |
562 | kfree_device_rcu); | |
563 | } | |
564 | } | |
565 | ||
566 | /** | |
567 | * dev_pm_opp_remove() - Remove an OPP from OPP list | |
568 | * @dev: device for which we do this operation | |
569 | * @freq: OPP to remove with matching 'freq' | |
570 | * | |
571 | * This function removes an opp from the opp list. | |
572 | */ | |
573 | void dev_pm_opp_remove(struct device *dev, unsigned long freq) | |
574 | { | |
575 | struct dev_pm_opp *opp; | |
576 | struct device_opp *dev_opp; | |
577 | bool found = false; | |
578 | ||
579 | /* Hold our list modification lock here */ | |
580 | mutex_lock(&dev_opp_list_lock); | |
581 | ||
582 | dev_opp = find_device_opp(dev); | |
583 | if (IS_ERR(dev_opp)) | |
584 | goto unlock; | |
585 | ||
586 | list_for_each_entry(opp, &dev_opp->opp_list, node) { | |
587 | if (opp->rate == freq) { | |
588 | found = true; | |
589 | break; | |
590 | } | |
591 | } | |
592 | ||
593 | if (!found) { | |
594 | dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n", | |
595 | __func__, freq); | |
596 | goto unlock; | |
597 | } | |
598 | ||
599 | __dev_pm_opp_remove(dev_opp, opp); | |
600 | unlock: | |
601 | mutex_unlock(&dev_opp_list_lock); | |
602 | } | |
603 | EXPORT_SYMBOL_GPL(dev_pm_opp_remove); | |
604 | ||
e1f60b29 NM |
605 | /** |
606 | * opp_set_availability() - helper to set the availability of an opp | |
607 | * @dev: device for which we do this operation | |
608 | * @freq: OPP frequency to modify availability | |
609 | * @availability_req: availability status requested for this opp | |
610 | * | |
611 | * Set the availability of an OPP with an RCU operation, opp_{enable,disable} | |
612 | * share a common logic which is isolated here. | |
613 | * | |
614 | * Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the | |
615 | * copy operation, returns 0 if no modifcation was done OR modification was | |
616 | * successful. | |
617 | * | |
618 | * Locking: The internal device_opp and opp structures are RCU protected. | |
619 | * Hence this function internally uses RCU updater strategy with mutex locks to | |
620 | * keep the integrity of the internal data structures. Callers should ensure | |
621 | * that this function is *NOT* called under RCU protection or in contexts where | |
622 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
623 | */ | |
624 | static int opp_set_availability(struct device *dev, unsigned long freq, | |
625 | bool availability_req) | |
626 | { | |
29df0ee1 | 627 | struct device_opp *dev_opp; |
47d43ba7 | 628 | struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV); |
e1f60b29 NM |
629 | int r = 0; |
630 | ||
631 | /* keep the node allocated */ | |
47d43ba7 | 632 | new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL); |
e1f60b29 NM |
633 | if (!new_opp) { |
634 | dev_warn(dev, "%s: Unable to create OPP\n", __func__); | |
635 | return -ENOMEM; | |
636 | } | |
637 | ||
638 | mutex_lock(&dev_opp_list_lock); | |
639 | ||
640 | /* Find the device_opp */ | |
29df0ee1 | 641 | dev_opp = find_device_opp(dev); |
e1f60b29 NM |
642 | if (IS_ERR(dev_opp)) { |
643 | r = PTR_ERR(dev_opp); | |
644 | dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r); | |
645 | goto unlock; | |
646 | } | |
647 | ||
648 | /* Do we have the frequency? */ | |
649 | list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) { | |
650 | if (tmp_opp->rate == freq) { | |
651 | opp = tmp_opp; | |
652 | break; | |
653 | } | |
654 | } | |
655 | if (IS_ERR(opp)) { | |
656 | r = PTR_ERR(opp); | |
657 | goto unlock; | |
658 | } | |
659 | ||
660 | /* Is update really needed? */ | |
661 | if (opp->available == availability_req) | |
662 | goto unlock; | |
663 | /* copy the old data over */ | |
664 | *new_opp = *opp; | |
665 | ||
666 | /* plug in new node */ | |
667 | new_opp->available = availability_req; | |
668 | ||
669 | list_replace_rcu(&opp->node, &new_opp->node); | |
670 | mutex_unlock(&dev_opp_list_lock); | |
b4037aaa | 671 | call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu); |
e1f60b29 | 672 | |
03ca370f MH |
673 | /* Notify the change of the OPP availability */ |
674 | if (availability_req) | |
cd1a068a | 675 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ENABLE, |
03ca370f MH |
676 | new_opp); |
677 | else | |
cd1a068a | 678 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_DISABLE, |
03ca370f MH |
679 | new_opp); |
680 | ||
dde8437d | 681 | return 0; |
e1f60b29 NM |
682 | |
683 | unlock: | |
684 | mutex_unlock(&dev_opp_list_lock); | |
e1f60b29 NM |
685 | kfree(new_opp); |
686 | return r; | |
687 | } | |
688 | ||
689 | /** | |
5d4879cd | 690 | * dev_pm_opp_enable() - Enable a specific OPP |
e1f60b29 NM |
691 | * @dev: device for which we do this operation |
692 | * @freq: OPP frequency to enable | |
693 | * | |
694 | * Enables a provided opp. If the operation is valid, this returns 0, else the | |
695 | * corresponding error value. It is meant to be used for users an OPP available | |
5d4879cd | 696 | * after being temporarily made unavailable with dev_pm_opp_disable. |
e1f60b29 NM |
697 | * |
698 | * Locking: The internal device_opp and opp structures are RCU protected. | |
699 | * Hence this function indirectly uses RCU and mutex locks to keep the | |
700 | * integrity of the internal data structures. Callers should ensure that | |
701 | * this function is *NOT* called under RCU protection or in contexts where | |
702 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
703 | */ | |
5d4879cd | 704 | int dev_pm_opp_enable(struct device *dev, unsigned long freq) |
e1f60b29 NM |
705 | { |
706 | return opp_set_availability(dev, freq, true); | |
707 | } | |
5d4879cd | 708 | EXPORT_SYMBOL_GPL(dev_pm_opp_enable); |
e1f60b29 NM |
709 | |
710 | /** | |
5d4879cd | 711 | * dev_pm_opp_disable() - Disable a specific OPP |
e1f60b29 NM |
712 | * @dev: device for which we do this operation |
713 | * @freq: OPP frequency to disable | |
714 | * | |
715 | * Disables a provided opp. If the operation is valid, this returns | |
716 | * 0, else the corresponding error value. It is meant to be a temporary | |
717 | * control by users to make this OPP not available until the circumstances are | |
5d4879cd | 718 | * right to make it available again (with a call to dev_pm_opp_enable). |
e1f60b29 NM |
719 | * |
720 | * Locking: The internal device_opp and opp structures are RCU protected. | |
721 | * Hence this function indirectly uses RCU and mutex locks to keep the | |
722 | * integrity of the internal data structures. Callers should ensure that | |
723 | * this function is *NOT* called under RCU protection or in contexts where | |
724 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
725 | */ | |
5d4879cd | 726 | int dev_pm_opp_disable(struct device *dev, unsigned long freq) |
e1f60b29 NM |
727 | { |
728 | return opp_set_availability(dev, freq, false); | |
729 | } | |
5d4879cd | 730 | EXPORT_SYMBOL_GPL(dev_pm_opp_disable); |
e1f60b29 | 731 | |
03ca370f | 732 | /** |
5d4879cd | 733 | * dev_pm_opp_get_notifier() - find notifier_head of the device with opp |
03ca370f MH |
734 | * @dev: device pointer used to lookup device OPPs. |
735 | */ | |
5d4879cd | 736 | struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev) |
03ca370f MH |
737 | { |
738 | struct device_opp *dev_opp = find_device_opp(dev); | |
739 | ||
740 | if (IS_ERR(dev_opp)) | |
156acb16 | 741 | return ERR_CAST(dev_opp); /* matching type */ |
03ca370f | 742 | |
cd1a068a | 743 | return &dev_opp->srcu_head; |
03ca370f | 744 | } |
b496dfbc SG |
745 | |
746 | #ifdef CONFIG_OF | |
747 | /** | |
748 | * of_init_opp_table() - Initialize opp table from device tree | |
749 | * @dev: device pointer used to lookup device OPPs. | |
750 | * | |
751 | * Register the initial OPP table with the OPP library for given device. | |
752 | */ | |
753 | int of_init_opp_table(struct device *dev) | |
754 | { | |
755 | const struct property *prop; | |
756 | const __be32 *val; | |
757 | int nr; | |
758 | ||
759 | prop = of_find_property(dev->of_node, "operating-points", NULL); | |
760 | if (!prop) | |
761 | return -ENODEV; | |
762 | if (!prop->value) | |
763 | return -ENODATA; | |
764 | ||
765 | /* | |
766 | * Each OPP is a set of tuples consisting of frequency and | |
767 | * voltage like <freq-kHz vol-uV>. | |
768 | */ | |
769 | nr = prop->length / sizeof(u32); | |
770 | if (nr % 2) { | |
771 | dev_err(dev, "%s: Invalid OPP list\n", __func__); | |
772 | return -EINVAL; | |
773 | } | |
774 | ||
775 | val = prop->value; | |
776 | while (nr) { | |
777 | unsigned long freq = be32_to_cpup(val++) * 1000; | |
778 | unsigned long volt = be32_to_cpup(val++); | |
779 | ||
38393409 | 780 | if (dev_pm_opp_add_dynamic(dev, freq, volt, false)) |
b496dfbc SG |
781 | dev_warn(dev, "%s: Failed to add OPP %ld\n", |
782 | __func__, freq); | |
b496dfbc SG |
783 | nr -= 2; |
784 | } | |
785 | ||
786 | return 0; | |
787 | } | |
74c46c6e | 788 | EXPORT_SYMBOL_GPL(of_init_opp_table); |
129eec55 VK |
789 | |
790 | /** | |
791 | * of_free_opp_table() - Free OPP table entries created from static DT entries | |
792 | * @dev: device pointer used to lookup device OPPs. | |
793 | * | |
794 | * Free OPPs created using static entries present in DT. | |
795 | */ | |
796 | void of_free_opp_table(struct device *dev) | |
797 | { | |
2a6127d0 | 798 | struct device_opp *dev_opp; |
129eec55 VK |
799 | struct dev_pm_opp *opp, *tmp; |
800 | ||
801 | /* Check for existing list for 'dev' */ | |
802 | dev_opp = find_device_opp(dev); | |
0fe30da2 DT |
803 | if (IS_ERR(dev_opp)) { |
804 | int error = PTR_ERR(dev_opp); | |
805 | if (error != -ENODEV) | |
806 | WARN(1, "%s: dev_opp: %d\n", | |
807 | IS_ERR_OR_NULL(dev) ? | |
808 | "Invalid device" : dev_name(dev), | |
809 | error); | |
129eec55 | 810 | return; |
0fe30da2 | 811 | } |
129eec55 VK |
812 | |
813 | /* Hold our list modification lock here */ | |
814 | mutex_lock(&dev_opp_list_lock); | |
815 | ||
816 | /* Free static OPPs */ | |
817 | list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) { | |
818 | if (!opp->dynamic) | |
819 | __dev_pm_opp_remove(dev_opp, opp); | |
820 | } | |
821 | ||
822 | mutex_unlock(&dev_opp_list_lock); | |
823 | } | |
824 | EXPORT_SYMBOL_GPL(of_free_opp_table); | |
b496dfbc | 825 | #endif |