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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> | |
17 | #include <linux/init.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/cpufreq.h> | |
51990e82 | 20 | #include <linux/device.h> |
e1f60b29 NM |
21 | #include <linux/list.h> |
22 | #include <linux/rculist.h> | |
23 | #include <linux/rcupdate.h> | |
24 | #include <linux/opp.h> | |
b496dfbc | 25 | #include <linux/of.h> |
80126ce7 | 26 | #include <linux/export.h> |
e1f60b29 NM |
27 | |
28 | /* | |
29 | * Internal data structure organization with the OPP layer library is as | |
30 | * follows: | |
31 | * dev_opp_list (root) | |
32 | * |- device 1 (represents voltage domain 1) | |
33 | * | |- opp 1 (availability, freq, voltage) | |
34 | * | |- opp 2 .. | |
35 | * ... ... | |
36 | * | `- opp n .. | |
37 | * |- device 2 (represents the next voltage domain) | |
38 | * ... | |
39 | * `- device m (represents mth voltage domain) | |
40 | * device 1, 2.. are represented by dev_opp structure while each opp | |
41 | * is represented by the opp structure. | |
42 | */ | |
43 | ||
44 | /** | |
45 | * struct opp - Generic OPP description structure | |
46 | * @node: opp list node. The nodes are maintained throughout the lifetime | |
47 | * of boot. It is expected only an optimal set of OPPs are | |
48 | * added to the library by the SoC framework. | |
49 | * RCU usage: opp list is traversed with RCU locks. node | |
50 | * modification is possible realtime, hence the modifications | |
51 | * are protected by the dev_opp_list_lock for integrity. | |
52 | * IMPORTANT: the opp nodes should be maintained in increasing | |
53 | * order. | |
54 | * @available: true/false - marks if this OPP as available or not | |
55 | * @rate: Frequency in hertz | |
56 | * @u_volt: Nominal voltage in microvolts corresponding to this OPP | |
57 | * @dev_opp: points back to the device_opp struct this opp belongs to | |
58 | * | |
59 | * This structure stores the OPP information for a given device. | |
60 | */ | |
61 | struct opp { | |
62 | struct list_head node; | |
63 | ||
64 | bool available; | |
65 | unsigned long rate; | |
66 | unsigned long u_volt; | |
67 | ||
68 | struct device_opp *dev_opp; | |
dde8437d | 69 | struct rcu_head head; |
e1f60b29 NM |
70 | }; |
71 | ||
72 | /** | |
73 | * struct device_opp - Device opp structure | |
74 | * @node: list node - contains the devices with OPPs that | |
75 | * have been registered. Nodes once added are not modified in this | |
76 | * list. | |
77 | * RCU usage: nodes are not modified in the list of device_opp, | |
78 | * however addition is possible and is secured by dev_opp_list_lock | |
79 | * @dev: device pointer | |
03ca370f | 80 | * @head: notifier head to notify the OPP availability changes. |
e1f60b29 NM |
81 | * @opp_list: list of opps |
82 | * | |
83 | * This is an internal data structure maintaining the link to opps attached to | |
84 | * a device. This structure is not meant to be shared to users as it is | |
85 | * meant for book keeping and private to OPP library | |
86 | */ | |
87 | struct device_opp { | |
88 | struct list_head node; | |
89 | ||
90 | struct device *dev; | |
03ca370f | 91 | struct srcu_notifier_head head; |
e1f60b29 NM |
92 | struct list_head opp_list; |
93 | }; | |
94 | ||
95 | /* | |
96 | * The root of the list of all devices. All device_opp structures branch off | |
97 | * from here, with each device_opp containing the list of opp it supports in | |
98 | * various states of availability. | |
99 | */ | |
100 | static LIST_HEAD(dev_opp_list); | |
101 | /* Lock to allow exclusive modification to the device and opp lists */ | |
102 | static DEFINE_MUTEX(dev_opp_list_lock); | |
103 | ||
104 | /** | |
105 | * find_device_opp() - find device_opp struct using device pointer | |
106 | * @dev: device pointer used to lookup device OPPs | |
107 | * | |
108 | * Search list of device OPPs for one containing matching device. Does a RCU | |
109 | * reader operation to grab the pointer needed. | |
110 | * | |
111 | * Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or | |
112 | * -EINVAL based on type of error. | |
113 | * | |
114 | * Locking: This function must be called under rcu_read_lock(). device_opp | |
115 | * is a RCU protected pointer. This means that device_opp is valid as long | |
116 | * as we are under RCU lock. | |
117 | */ | |
118 | static struct device_opp *find_device_opp(struct device *dev) | |
119 | { | |
120 | struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV); | |
121 | ||
122 | if (unlikely(IS_ERR_OR_NULL(dev))) { | |
123 | pr_err("%s: Invalid parameters\n", __func__); | |
124 | return ERR_PTR(-EINVAL); | |
125 | } | |
126 | ||
127 | list_for_each_entry_rcu(tmp_dev_opp, &dev_opp_list, node) { | |
128 | if (tmp_dev_opp->dev == dev) { | |
129 | dev_opp = tmp_dev_opp; | |
130 | break; | |
131 | } | |
132 | } | |
133 | ||
134 | return dev_opp; | |
135 | } | |
136 | ||
137 | /** | |
138 | * opp_get_voltage() - Gets the voltage corresponding to an available opp | |
139 | * @opp: opp for which voltage has to be returned for | |
140 | * | |
141 | * Return voltage in micro volt corresponding to the opp, else | |
142 | * return 0 | |
143 | * | |
144 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
145 | * protected pointer. This means that opp which could have been fetched by | |
146 | * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are | |
147 | * under RCU lock. The pointer returned by the opp_find_freq family must be | |
148 | * used in the same section as the usage of this function with the pointer | |
149 | * prior to unlocking with rcu_read_unlock() to maintain the integrity of the | |
150 | * pointer. | |
151 | */ | |
152 | unsigned long opp_get_voltage(struct opp *opp) | |
153 | { | |
154 | struct opp *tmp_opp; | |
155 | unsigned long v = 0; | |
156 | ||
157 | tmp_opp = rcu_dereference(opp); | |
158 | if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) | |
159 | pr_err("%s: Invalid parameters\n", __func__); | |
160 | else | |
161 | v = tmp_opp->u_volt; | |
162 | ||
163 | return v; | |
164 | } | |
80126ce7 | 165 | EXPORT_SYMBOL(opp_get_voltage); |
e1f60b29 NM |
166 | |
167 | /** | |
168 | * opp_get_freq() - Gets the frequency corresponding to an available opp | |
169 | * @opp: opp for which frequency has to be returned for | |
170 | * | |
171 | * Return frequency in hertz corresponding to the opp, else | |
172 | * return 0 | |
173 | * | |
174 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
175 | * protected pointer. This means that opp which could have been fetched by | |
176 | * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are | |
177 | * under RCU lock. The pointer returned by the opp_find_freq family must be | |
178 | * used in the same section as the usage of this function with the pointer | |
179 | * prior to unlocking with rcu_read_unlock() to maintain the integrity of the | |
180 | * pointer. | |
181 | */ | |
182 | unsigned long opp_get_freq(struct opp *opp) | |
183 | { | |
184 | struct opp *tmp_opp; | |
185 | unsigned long f = 0; | |
186 | ||
187 | tmp_opp = rcu_dereference(opp); | |
188 | if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) | |
189 | pr_err("%s: Invalid parameters\n", __func__); | |
190 | else | |
191 | f = tmp_opp->rate; | |
192 | ||
193 | return f; | |
194 | } | |
80126ce7 | 195 | EXPORT_SYMBOL(opp_get_freq); |
e1f60b29 NM |
196 | |
197 | /** | |
198 | * opp_get_opp_count() - Get number of opps available in the opp list | |
199 | * @dev: device for which we do this operation | |
200 | * | |
201 | * This function returns the number of available opps if there are any, | |
202 | * else returns 0 if none or the corresponding error value. | |
203 | * | |
204 | * Locking: This function must be called under rcu_read_lock(). This function | |
205 | * internally references two RCU protected structures: device_opp and opp which | |
206 | * are safe as long as we are under a common RCU locked section. | |
207 | */ | |
208 | int opp_get_opp_count(struct device *dev) | |
209 | { | |
210 | struct device_opp *dev_opp; | |
211 | struct opp *temp_opp; | |
212 | int count = 0; | |
213 | ||
214 | dev_opp = find_device_opp(dev); | |
215 | if (IS_ERR(dev_opp)) { | |
216 | int r = PTR_ERR(dev_opp); | |
217 | dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r); | |
218 | return r; | |
219 | } | |
220 | ||
221 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
222 | if (temp_opp->available) | |
223 | count++; | |
224 | } | |
225 | ||
226 | return count; | |
227 | } | |
80126ce7 | 228 | EXPORT_SYMBOL(opp_get_opp_count); |
e1f60b29 NM |
229 | |
230 | /** | |
231 | * opp_find_freq_exact() - search for an exact frequency | |
232 | * @dev: device for which we do this operation | |
233 | * @freq: frequency to search for | |
7ae49618 | 234 | * @available: true/false - match for available opp |
e1f60b29 NM |
235 | * |
236 | * Searches for exact match in the opp list and returns pointer to the matching | |
237 | * opp if found, else returns ERR_PTR in case of error and should be handled | |
238 | * using IS_ERR. | |
239 | * | |
240 | * Note: available is a modifier for the search. if available=true, then the | |
241 | * match is for exact matching frequency and is available in the stored OPP | |
242 | * table. if false, the match is for exact frequency which is not available. | |
243 | * | |
244 | * This provides a mechanism to enable an opp which is not available currently | |
245 | * or the opposite as well. | |
246 | * | |
247 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
248 | * protected pointer. The reason for the same is that the opp pointer which is | |
249 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
250 | * under the locked area. The pointer returned must be used prior to unlocking | |
251 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
252 | */ | |
253 | struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq, | |
254 | bool available) | |
255 | { | |
256 | struct device_opp *dev_opp; | |
257 | struct opp *temp_opp, *opp = ERR_PTR(-ENODEV); | |
258 | ||
259 | dev_opp = find_device_opp(dev); | |
260 | if (IS_ERR(dev_opp)) { | |
261 | int r = PTR_ERR(dev_opp); | |
262 | dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r); | |
263 | return ERR_PTR(r); | |
264 | } | |
265 | ||
266 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
267 | if (temp_opp->available == available && | |
268 | temp_opp->rate == freq) { | |
269 | opp = temp_opp; | |
270 | break; | |
271 | } | |
272 | } | |
273 | ||
274 | return opp; | |
275 | } | |
80126ce7 | 276 | EXPORT_SYMBOL(opp_find_freq_exact); |
e1f60b29 NM |
277 | |
278 | /** | |
279 | * opp_find_freq_ceil() - Search for an rounded ceil freq | |
280 | * @dev: device for which we do this operation | |
281 | * @freq: Start frequency | |
282 | * | |
283 | * Search for the matching ceil *available* OPP from a starting freq | |
284 | * for a device. | |
285 | * | |
286 | * Returns matching *opp and refreshes *freq accordingly, else returns | |
287 | * ERR_PTR in case of error and should be handled using IS_ERR. | |
288 | * | |
289 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
290 | * protected pointer. The reason for the same is that the opp pointer which is | |
291 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
292 | * under the locked area. The pointer returned must be used prior to unlocking | |
293 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
294 | */ | |
295 | struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq) | |
296 | { | |
297 | struct device_opp *dev_opp; | |
298 | struct opp *temp_opp, *opp = ERR_PTR(-ENODEV); | |
299 | ||
300 | if (!dev || !freq) { | |
301 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); | |
302 | return ERR_PTR(-EINVAL); | |
303 | } | |
304 | ||
305 | dev_opp = find_device_opp(dev); | |
306 | if (IS_ERR(dev_opp)) | |
307 | return opp; | |
308 | ||
309 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
310 | if (temp_opp->available && temp_opp->rate >= *freq) { | |
311 | opp = temp_opp; | |
312 | *freq = opp->rate; | |
313 | break; | |
314 | } | |
315 | } | |
316 | ||
317 | return opp; | |
318 | } | |
80126ce7 | 319 | EXPORT_SYMBOL(opp_find_freq_ceil); |
e1f60b29 NM |
320 | |
321 | /** | |
322 | * opp_find_freq_floor() - Search for a rounded floor freq | |
323 | * @dev: device for which we do this operation | |
324 | * @freq: Start frequency | |
325 | * | |
326 | * Search for the matching floor *available* OPP from a starting freq | |
327 | * for a device. | |
328 | * | |
329 | * Returns matching *opp and refreshes *freq accordingly, else returns | |
330 | * ERR_PTR in case of error and should be handled using IS_ERR. | |
331 | * | |
332 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
333 | * protected pointer. The reason for the same is that the opp pointer which is | |
334 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
335 | * under the locked area. The pointer returned must be used prior to unlocking | |
336 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
337 | */ | |
338 | struct opp *opp_find_freq_floor(struct device *dev, unsigned long *freq) | |
339 | { | |
340 | struct device_opp *dev_opp; | |
341 | struct opp *temp_opp, *opp = ERR_PTR(-ENODEV); | |
342 | ||
343 | if (!dev || !freq) { | |
344 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); | |
345 | return ERR_PTR(-EINVAL); | |
346 | } | |
347 | ||
348 | dev_opp = find_device_opp(dev); | |
349 | if (IS_ERR(dev_opp)) | |
350 | return opp; | |
351 | ||
352 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
353 | if (temp_opp->available) { | |
354 | /* go to the next node, before choosing prev */ | |
355 | if (temp_opp->rate > *freq) | |
356 | break; | |
357 | else | |
358 | opp = temp_opp; | |
359 | } | |
360 | } | |
361 | if (!IS_ERR(opp)) | |
362 | *freq = opp->rate; | |
363 | ||
364 | return opp; | |
365 | } | |
80126ce7 | 366 | EXPORT_SYMBOL(opp_find_freq_floor); |
e1f60b29 NM |
367 | |
368 | /** | |
369 | * opp_add() - Add an OPP table from a table definitions | |
370 | * @dev: device for which we do this operation | |
371 | * @freq: Frequency in Hz for this OPP | |
372 | * @u_volt: Voltage in uVolts for this OPP | |
373 | * | |
374 | * This function adds an opp definition to the opp list and returns status. | |
375 | * The opp is made available by default and it can be controlled using | |
376 | * opp_enable/disable functions. | |
377 | * | |
378 | * Locking: The internal device_opp and opp structures are RCU protected. | |
379 | * Hence this function internally uses RCU updater strategy with mutex locks | |
380 | * to keep the integrity of the internal data structures. Callers should ensure | |
381 | * that this function is *NOT* called under RCU protection or in contexts where | |
382 | * mutex cannot be locked. | |
383 | */ | |
384 | int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) | |
385 | { | |
386 | struct device_opp *dev_opp = NULL; | |
387 | struct opp *opp, *new_opp; | |
388 | struct list_head *head; | |
389 | ||
390 | /* allocate new OPP node */ | |
391 | new_opp = kzalloc(sizeof(struct opp), GFP_KERNEL); | |
392 | if (!new_opp) { | |
393 | dev_warn(dev, "%s: Unable to create new OPP node\n", __func__); | |
394 | return -ENOMEM; | |
395 | } | |
396 | ||
397 | /* Hold our list modification lock here */ | |
398 | mutex_lock(&dev_opp_list_lock); | |
399 | ||
400 | /* Check for existing list for 'dev' */ | |
401 | dev_opp = find_device_opp(dev); | |
402 | if (IS_ERR(dev_opp)) { | |
403 | /* | |
404 | * Allocate a new device OPP table. In the infrequent case | |
405 | * where a new device is needed to be added, we pay this | |
406 | * penalty. | |
407 | */ | |
408 | dev_opp = kzalloc(sizeof(struct device_opp), GFP_KERNEL); | |
409 | if (!dev_opp) { | |
410 | mutex_unlock(&dev_opp_list_lock); | |
411 | kfree(new_opp); | |
412 | dev_warn(dev, | |
413 | "%s: Unable to create device OPP structure\n", | |
414 | __func__); | |
415 | return -ENOMEM; | |
416 | } | |
417 | ||
418 | dev_opp->dev = dev; | |
03ca370f | 419 | srcu_init_notifier_head(&dev_opp->head); |
e1f60b29 NM |
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 | } | |
425 | ||
426 | /* populate the opp table */ | |
427 | new_opp->dev_opp = dev_opp; | |
428 | new_opp->rate = freq; | |
429 | new_opp->u_volt = u_volt; | |
430 | new_opp->available = true; | |
431 | ||
432 | /* Insert new OPP in order of increasing frequency */ | |
433 | head = &dev_opp->opp_list; | |
434 | list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) { | |
435 | if (new_opp->rate < opp->rate) | |
436 | break; | |
437 | else | |
438 | head = &opp->node; | |
439 | } | |
440 | ||
441 | list_add_rcu(&new_opp->node, head); | |
442 | mutex_unlock(&dev_opp_list_lock); | |
443 | ||
03ca370f MH |
444 | /* |
445 | * Notify the changes in the availability of the operable | |
446 | * frequency/voltage list. | |
447 | */ | |
448 | srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ADD, new_opp); | |
e1f60b29 NM |
449 | return 0; |
450 | } | |
451 | ||
dde8437d VG |
452 | /** |
453 | * opp_free_rcu() - helper to clear the struct opp when grace period has | |
454 | * elapsed without blocking the the caller of opp_set_availability | |
455 | */ | |
456 | static void opp_free_rcu(struct rcu_head *head) | |
457 | { | |
458 | struct opp *opp = container_of(head, struct opp, head); | |
459 | ||
460 | kfree(opp); | |
461 | } | |
462 | ||
e1f60b29 NM |
463 | /** |
464 | * opp_set_availability() - helper to set the availability of an opp | |
465 | * @dev: device for which we do this operation | |
466 | * @freq: OPP frequency to modify availability | |
467 | * @availability_req: availability status requested for this opp | |
468 | * | |
469 | * Set the availability of an OPP with an RCU operation, opp_{enable,disable} | |
470 | * share a common logic which is isolated here. | |
471 | * | |
472 | * Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the | |
473 | * copy operation, returns 0 if no modifcation was done OR modification was | |
474 | * successful. | |
475 | * | |
476 | * Locking: The internal device_opp and opp structures are RCU protected. | |
477 | * Hence this function internally uses RCU updater strategy with mutex locks to | |
478 | * keep the integrity of the internal data structures. Callers should ensure | |
479 | * that this function is *NOT* called under RCU protection or in contexts where | |
480 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
481 | */ | |
482 | static int opp_set_availability(struct device *dev, unsigned long freq, | |
483 | bool availability_req) | |
484 | { | |
fc92805a | 485 | struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV); |
e1f60b29 NM |
486 | struct opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV); |
487 | int r = 0; | |
488 | ||
489 | /* keep the node allocated */ | |
490 | new_opp = kmalloc(sizeof(struct opp), GFP_KERNEL); | |
491 | if (!new_opp) { | |
492 | dev_warn(dev, "%s: Unable to create OPP\n", __func__); | |
493 | return -ENOMEM; | |
494 | } | |
495 | ||
496 | mutex_lock(&dev_opp_list_lock); | |
497 | ||
498 | /* Find the device_opp */ | |
499 | list_for_each_entry(tmp_dev_opp, &dev_opp_list, node) { | |
500 | if (dev == tmp_dev_opp->dev) { | |
501 | dev_opp = tmp_dev_opp; | |
502 | break; | |
503 | } | |
504 | } | |
505 | if (IS_ERR(dev_opp)) { | |
506 | r = PTR_ERR(dev_opp); | |
507 | dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r); | |
508 | goto unlock; | |
509 | } | |
510 | ||
511 | /* Do we have the frequency? */ | |
512 | list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) { | |
513 | if (tmp_opp->rate == freq) { | |
514 | opp = tmp_opp; | |
515 | break; | |
516 | } | |
517 | } | |
518 | if (IS_ERR(opp)) { | |
519 | r = PTR_ERR(opp); | |
520 | goto unlock; | |
521 | } | |
522 | ||
523 | /* Is update really needed? */ | |
524 | if (opp->available == availability_req) | |
525 | goto unlock; | |
526 | /* copy the old data over */ | |
527 | *new_opp = *opp; | |
528 | ||
529 | /* plug in new node */ | |
530 | new_opp->available = availability_req; | |
531 | ||
532 | list_replace_rcu(&opp->node, &new_opp->node); | |
533 | mutex_unlock(&dev_opp_list_lock); | |
dde8437d | 534 | call_rcu(&opp->head, opp_free_rcu); |
e1f60b29 | 535 | |
03ca370f MH |
536 | /* Notify the change of the OPP availability */ |
537 | if (availability_req) | |
538 | srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ENABLE, | |
539 | new_opp); | |
540 | else | |
541 | srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_DISABLE, | |
542 | new_opp); | |
543 | ||
dde8437d | 544 | return 0; |
e1f60b29 NM |
545 | |
546 | unlock: | |
547 | mutex_unlock(&dev_opp_list_lock); | |
e1f60b29 NM |
548 | kfree(new_opp); |
549 | return r; | |
550 | } | |
551 | ||
552 | /** | |
553 | * opp_enable() - Enable a specific OPP | |
554 | * @dev: device for which we do this operation | |
555 | * @freq: OPP frequency to enable | |
556 | * | |
557 | * Enables a provided opp. If the operation is valid, this returns 0, else the | |
558 | * corresponding error value. It is meant to be used for users an OPP available | |
559 | * after being temporarily made unavailable with opp_disable. | |
560 | * | |
561 | * Locking: The internal device_opp and opp structures are RCU protected. | |
562 | * Hence this function indirectly uses RCU and mutex locks to keep the | |
563 | * integrity of the internal data structures. Callers should ensure that | |
564 | * this function is *NOT* called under RCU protection or in contexts where | |
565 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
566 | */ | |
567 | int opp_enable(struct device *dev, unsigned long freq) | |
568 | { | |
569 | return opp_set_availability(dev, freq, true); | |
570 | } | |
80126ce7 | 571 | EXPORT_SYMBOL(opp_enable); |
e1f60b29 NM |
572 | |
573 | /** | |
574 | * opp_disable() - Disable a specific OPP | |
575 | * @dev: device for which we do this operation | |
576 | * @freq: OPP frequency to disable | |
577 | * | |
578 | * Disables a provided opp. If the operation is valid, this returns | |
579 | * 0, else the corresponding error value. It is meant to be a temporary | |
580 | * control by users to make this OPP not available until the circumstances are | |
581 | * right to make it available again (with a call to opp_enable). | |
582 | * | |
583 | * Locking: The internal device_opp and opp structures are RCU protected. | |
584 | * Hence this function indirectly uses RCU and mutex locks to keep the | |
585 | * integrity of the internal data structures. Callers should ensure that | |
586 | * this function is *NOT* called under RCU protection or in contexts where | |
587 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
588 | */ | |
589 | int opp_disable(struct device *dev, unsigned long freq) | |
590 | { | |
591 | return opp_set_availability(dev, freq, false); | |
592 | } | |
80126ce7 | 593 | EXPORT_SYMBOL(opp_disable); |
e1f60b29 NM |
594 | |
595 | #ifdef CONFIG_CPU_FREQ | |
596 | /** | |
597 | * opp_init_cpufreq_table() - create a cpufreq table for a device | |
598 | * @dev: device for which we do this operation | |
599 | * @table: Cpufreq table returned back to caller | |
600 | * | |
601 | * Generate a cpufreq table for a provided device- this assumes that the | |
602 | * opp list is already initialized and ready for usage. | |
603 | * | |
604 | * This function allocates required memory for the cpufreq table. It is | |
605 | * expected that the caller does the required maintenance such as freeing | |
606 | * the table as required. | |
607 | * | |
608 | * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM | |
609 | * if no memory available for the operation (table is not populated), returns 0 | |
610 | * if successful and table is populated. | |
611 | * | |
612 | * WARNING: It is important for the callers to ensure refreshing their copy of | |
613 | * the table if any of the mentioned functions have been invoked in the interim. | |
614 | * | |
615 | * Locking: The internal device_opp and opp structures are RCU protected. | |
616 | * To simplify the logic, we pretend we are updater and hold relevant mutex here | |
617 | * Callers should ensure that this function is *NOT* called under RCU protection | |
618 | * or in contexts where mutex locking cannot be used. | |
619 | */ | |
620 | int opp_init_cpufreq_table(struct device *dev, | |
621 | struct cpufreq_frequency_table **table) | |
622 | { | |
623 | struct device_opp *dev_opp; | |
624 | struct opp *opp; | |
625 | struct cpufreq_frequency_table *freq_table; | |
626 | int i = 0; | |
627 | ||
628 | /* Pretend as if I am an updater */ | |
629 | mutex_lock(&dev_opp_list_lock); | |
630 | ||
631 | dev_opp = find_device_opp(dev); | |
632 | if (IS_ERR(dev_opp)) { | |
633 | int r = PTR_ERR(dev_opp); | |
634 | mutex_unlock(&dev_opp_list_lock); | |
635 | dev_err(dev, "%s: Device OPP not found (%d)\n", __func__, r); | |
636 | return r; | |
637 | } | |
638 | ||
639 | freq_table = kzalloc(sizeof(struct cpufreq_frequency_table) * | |
640 | (opp_get_opp_count(dev) + 1), GFP_KERNEL); | |
641 | if (!freq_table) { | |
642 | mutex_unlock(&dev_opp_list_lock); | |
643 | dev_warn(dev, "%s: Unable to allocate frequency table\n", | |
644 | __func__); | |
645 | return -ENOMEM; | |
646 | } | |
647 | ||
648 | list_for_each_entry(opp, &dev_opp->opp_list, node) { | |
649 | if (opp->available) { | |
650 | freq_table[i].index = i; | |
651 | freq_table[i].frequency = opp->rate / 1000; | |
652 | i++; | |
653 | } | |
654 | } | |
655 | mutex_unlock(&dev_opp_list_lock); | |
656 | ||
657 | freq_table[i].index = i; | |
658 | freq_table[i].frequency = CPUFREQ_TABLE_END; | |
659 | ||
660 | *table = &freq_table[0]; | |
661 | ||
662 | return 0; | |
663 | } | |
99f381d3 NM |
664 | |
665 | /** | |
666 | * opp_free_cpufreq_table() - free the cpufreq table | |
667 | * @dev: device for which we do this operation | |
668 | * @table: table to free | |
669 | * | |
670 | * Free up the table allocated by opp_init_cpufreq_table | |
671 | */ | |
672 | void opp_free_cpufreq_table(struct device *dev, | |
673 | struct cpufreq_frequency_table **table) | |
674 | { | |
675 | if (!table) | |
676 | return; | |
677 | ||
678 | kfree(*table); | |
679 | *table = NULL; | |
680 | } | |
e1f60b29 | 681 | #endif /* CONFIG_CPU_FREQ */ |
03ca370f MH |
682 | |
683 | /** | |
684 | * opp_get_notifier() - find notifier_head of the device with opp | |
685 | * @dev: device pointer used to lookup device OPPs. | |
686 | */ | |
687 | struct srcu_notifier_head *opp_get_notifier(struct device *dev) | |
688 | { | |
689 | struct device_opp *dev_opp = find_device_opp(dev); | |
690 | ||
691 | if (IS_ERR(dev_opp)) | |
156acb16 | 692 | return ERR_CAST(dev_opp); /* matching type */ |
03ca370f MH |
693 | |
694 | return &dev_opp->head; | |
695 | } | |
b496dfbc SG |
696 | |
697 | #ifdef CONFIG_OF | |
698 | /** | |
699 | * of_init_opp_table() - Initialize opp table from device tree | |
700 | * @dev: device pointer used to lookup device OPPs. | |
701 | * | |
702 | * Register the initial OPP table with the OPP library for given device. | |
703 | */ | |
704 | int of_init_opp_table(struct device *dev) | |
705 | { | |
706 | const struct property *prop; | |
707 | const __be32 *val; | |
708 | int nr; | |
709 | ||
710 | prop = of_find_property(dev->of_node, "operating-points", NULL); | |
711 | if (!prop) | |
712 | return -ENODEV; | |
713 | if (!prop->value) | |
714 | return -ENODATA; | |
715 | ||
716 | /* | |
717 | * Each OPP is a set of tuples consisting of frequency and | |
718 | * voltage like <freq-kHz vol-uV>. | |
719 | */ | |
720 | nr = prop->length / sizeof(u32); | |
721 | if (nr % 2) { | |
722 | dev_err(dev, "%s: Invalid OPP list\n", __func__); | |
723 | return -EINVAL; | |
724 | } | |
725 | ||
726 | val = prop->value; | |
727 | while (nr) { | |
728 | unsigned long freq = be32_to_cpup(val++) * 1000; | |
729 | unsigned long volt = be32_to_cpup(val++); | |
730 | ||
731 | if (opp_add(dev, freq, volt)) { | |
732 | dev_warn(dev, "%s: Failed to add OPP %ld\n", | |
733 | __func__, freq); | |
734 | continue; | |
735 | } | |
736 | nr -= 2; | |
737 | } | |
738 | ||
739 | return 0; | |
740 | } | |
741 | #endif |