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