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