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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/device.h> |
21 | #include <linux/list.h> |
22 | #include <linux/rculist.h> |
23 | #include <linux/rcupdate.h> |
24 | #include <linux/opp.h> |
25 | #include <linux/of.h> |
26 | #include <linux/export.h> |
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; |
69 | struct rcu_head head; |
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 |
80 | * @head: notifier head to notify the OPP availability changes. |
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; |
91 | struct srcu_notifier_head head; |
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 | } |
165 | EXPORT_SYMBOL_GPL(opp_get_voltage); |
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 | } |
195 | EXPORT_SYMBOL_GPL(opp_get_freq); |
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 | } |
228 | EXPORT_SYMBOL_GPL(opp_get_opp_count); |
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 |
234 | * @available: true/false - match for available opp |
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. Error return values can be: |
239 | * EINVAL: for bad pointer |
240 | * ERANGE: no match found for search |
241 | * ENODEV: if device not found in list of registered devices |
242 | * |
243 | * Note: available is a modifier for the search. if available=true, then the |
244 | * match is for exact matching frequency and is available in the stored OPP |
245 | * table. if false, the match is for exact frequency which is not available. |
246 | * |
247 | * This provides a mechanism to enable an opp which is not available currently |
248 | * or the opposite as well. |
249 | * |
250 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu |
251 | * protected pointer. The reason for the same is that the opp pointer which is |
252 | * returned will remain valid for use with opp_get_{voltage, freq} only while |
253 | * under the locked area. The pointer returned must be used prior to unlocking |
254 | * with rcu_read_unlock() to maintain the integrity of the pointer. |
255 | */ |
256 | struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq, |
257 | bool available) |
258 | { |
259 | struct device_opp *dev_opp; |
260 | struct opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
261 | |
262 | dev_opp = find_device_opp(dev); |
263 | if (IS_ERR(dev_opp)) { |
264 | int r = PTR_ERR(dev_opp); |
265 | dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r); |
266 | return ERR_PTR(r); |
267 | } |
268 | |
269 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { |
270 | if (temp_opp->available == available && |
271 | temp_opp->rate == freq) { |
272 | opp = temp_opp; |
273 | break; |
274 | } |
275 | } |
276 | |
277 | return opp; |
278 | } |
279 | EXPORT_SYMBOL_GPL(opp_find_freq_exact); |
280 | |
281 | /** |
282 | * opp_find_freq_ceil() - Search for an rounded ceil freq |
283 | * @dev: device for which we do this operation |
284 | * @freq: Start frequency |
285 | * |
286 | * Search for the matching ceil *available* OPP from a starting freq |
287 | * for a device. |
288 | * |
289 | * Returns matching *opp and refreshes *freq accordingly, else returns |
290 | * ERR_PTR in case of error and should be handled using IS_ERR. Error return |
291 | * values can be: |
292 | * EINVAL: for bad pointer |
293 | * ERANGE: no match found for search |
294 | * ENODEV: if device not found in list of registered devices |
295 | * |
296 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu |
297 | * protected pointer. The reason for the same is that the opp pointer which is |
298 | * returned will remain valid for use with opp_get_{voltage, freq} only while |
299 | * under the locked area. The pointer returned must be used prior to unlocking |
300 | * with rcu_read_unlock() to maintain the integrity of the pointer. |
301 | */ |
302 | struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq) |
303 | { |
304 | struct device_opp *dev_opp; |
305 | struct opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
306 | |
307 | if (!dev || !freq) { |
308 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); |
309 | return ERR_PTR(-EINVAL); |
310 | } |
311 | |
312 | dev_opp = find_device_opp(dev); |
313 | if (IS_ERR(dev_opp)) |
314 | return ERR_CAST(dev_opp); |
315 | |
316 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { |
317 | if (temp_opp->available && temp_opp->rate >= *freq) { |
318 | opp = temp_opp; |
319 | *freq = opp->rate; |
320 | break; |
321 | } |
322 | } |
323 | |
324 | return opp; |
325 | } |
326 | EXPORT_SYMBOL_GPL(opp_find_freq_ceil); |
327 | |
328 | /** |
329 | * opp_find_freq_floor() - Search for a rounded floor freq |
330 | * @dev: device for which we do this operation |
331 | * @freq: Start frequency |
332 | * |
333 | * Search for the matching floor *available* OPP from a starting freq |
334 | * for a device. |
335 | * |
336 | * Returns matching *opp and refreshes *freq accordingly, else returns |
337 | * ERR_PTR in case of error and should be handled using IS_ERR. Error return |
338 | * values can be: |
339 | * EINVAL: for bad pointer |
340 | * ERANGE: no match found for search |
341 | * ENODEV: if device not found in list of registered devices |
342 | * |
343 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu |
344 | * protected pointer. The reason for the same is that the opp pointer which is |
345 | * returned will remain valid for use with opp_get_{voltage, freq} only while |
346 | * under the locked area. The pointer returned must be used prior to unlocking |
347 | * with rcu_read_unlock() to maintain the integrity of the pointer. |
348 | */ |
349 | struct opp *opp_find_freq_floor(struct device *dev, unsigned long *freq) |
350 | { |
351 | struct device_opp *dev_opp; |
352 | struct opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
353 | |
354 | if (!dev || !freq) { |
355 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); |
356 | return ERR_PTR(-EINVAL); |
357 | } |
358 | |
359 | dev_opp = find_device_opp(dev); |
360 | if (IS_ERR(dev_opp)) |
361 | return ERR_CAST(dev_opp); |
362 | |
363 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { |
364 | if (temp_opp->available) { |
365 | /* go to the next node, before choosing prev */ |
366 | if (temp_opp->rate > *freq) |
367 | break; |
368 | else |
369 | opp = temp_opp; |
370 | } |
371 | } |
372 | if (!IS_ERR(opp)) |
373 | *freq = opp->rate; |
374 | |
375 | return opp; |
376 | } |
377 | EXPORT_SYMBOL_GPL(opp_find_freq_floor); |
378 | |
379 | /** |
380 | * opp_add() - Add an OPP table from a table definitions |
381 | * @dev: device for which we do this operation |
382 | * @freq: Frequency in Hz for this OPP |
383 | * @u_volt: Voltage in uVolts for this OPP |
384 | * |
385 | * This function adds an opp definition to the opp list and returns status. |
386 | * The opp is made available by default and it can be controlled using |
387 | * opp_enable/disable functions. |
388 | * |
389 | * Locking: The internal device_opp and opp structures are RCU protected. |
390 | * Hence this function internally uses RCU updater strategy with mutex locks |
391 | * to keep the integrity of the internal data structures. Callers should ensure |
392 | * that this function is *NOT* called under RCU protection or in contexts where |
393 | * mutex cannot be locked. |
394 | */ |
395 | int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) |
396 | { |
397 | struct device_opp *dev_opp = NULL; |
398 | struct opp *opp, *new_opp; |
399 | struct list_head *head; |
400 | |
401 | /* allocate new OPP node */ |
402 | new_opp = kzalloc(sizeof(struct opp), GFP_KERNEL); |
403 | if (!new_opp) { |
404 | dev_warn(dev, "%s: Unable to create new OPP node\n", __func__); |
405 | return -ENOMEM; |
406 | } |
407 | |
408 | /* Hold our list modification lock here */ |
409 | mutex_lock(&dev_opp_list_lock); |
410 | |
411 | /* Check for existing list for 'dev' */ |
412 | dev_opp = find_device_opp(dev); |
413 | if (IS_ERR(dev_opp)) { |
414 | /* |
415 | * Allocate a new device OPP table. In the infrequent case |
416 | * where a new device is needed to be added, we pay this |
417 | * penalty. |
418 | */ |
419 | dev_opp = kzalloc(sizeof(struct device_opp), GFP_KERNEL); |
420 | if (!dev_opp) { |
421 | mutex_unlock(&dev_opp_list_lock); |
422 | kfree(new_opp); |
423 | dev_warn(dev, |
424 | "%s: Unable to create device OPP structure\n", |
425 | __func__); |
426 | return -ENOMEM; |
427 | } |
428 | |
429 | dev_opp->dev = dev; |
430 | srcu_init_notifier_head(&dev_opp->head); |
431 | INIT_LIST_HEAD(&dev_opp->opp_list); |
432 | |
433 | /* Secure the device list modification */ |
434 | list_add_rcu(&dev_opp->node, &dev_opp_list); |
435 | } |
436 | |
437 | /* populate the opp table */ |
438 | new_opp->dev_opp = dev_opp; |
439 | new_opp->rate = freq; |
440 | new_opp->u_volt = u_volt; |
441 | new_opp->available = true; |
442 | |
443 | /* Insert new OPP in order of increasing frequency */ |
444 | head = &dev_opp->opp_list; |
445 | list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) { |
446 | if (new_opp->rate < opp->rate) |
447 | break; |
448 | else |
449 | head = &opp->node; |
450 | } |
451 | |
452 | list_add_rcu(&new_opp->node, head); |
453 | mutex_unlock(&dev_opp_list_lock); |
454 | |
455 | /* |
456 | * Notify the changes in the availability of the operable |
457 | * frequency/voltage list. |
458 | */ |
459 | srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ADD, new_opp); |
460 | return 0; |
461 | } |
462 | |
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 | { |
485 | struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV); |
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); |
534 | kfree_rcu(opp, head); |
535 | |
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 | |
544 | return 0; |
545 | |
546 | unlock: |
547 | mutex_unlock(&dev_opp_list_lock); |
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 | } |
571 | EXPORT_SYMBOL_GPL(opp_enable); |
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 | } |
593 | EXPORT_SYMBOL_GPL(opp_disable); |
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 | } |
664 | EXPORT_SYMBOL_GPL(opp_init_cpufreq_table); |
665 | |
666 | /** |
667 | * opp_free_cpufreq_table() - free the cpufreq table |
668 | * @dev: device for which we do this operation |
669 | * @table: table to free |
670 | * |
671 | * Free up the table allocated by opp_init_cpufreq_table |
672 | */ |
673 | void opp_free_cpufreq_table(struct device *dev, |
674 | struct cpufreq_frequency_table **table) |
675 | { |
676 | if (!table) |
677 | return; |
678 | |
679 | kfree(*table); |
680 | *table = NULL; |
681 | } |
682 | EXPORT_SYMBOL_GPL(opp_free_cpufreq_table); |
683 | #endif /* CONFIG_CPU_FREQ */ |
684 | |
685 | /** |
686 | * opp_get_notifier() - find notifier_head of the device with opp |
687 | * @dev: device pointer used to lookup device OPPs. |
688 | */ |
689 | struct srcu_notifier_head *opp_get_notifier(struct device *dev) |
690 | { |
691 | struct device_opp *dev_opp = find_device_opp(dev); |
692 | |
693 | if (IS_ERR(dev_opp)) |
694 | return ERR_CAST(dev_opp); /* matching type */ |
695 | |
696 | return &dev_opp->head; |
697 | } |
698 | |
699 | #ifdef CONFIG_OF |
700 | /** |
701 | * of_init_opp_table() - Initialize opp table from device tree |
702 | * @dev: device pointer used to lookup device OPPs. |
703 | * |
704 | * Register the initial OPP table with the OPP library for given device. |
705 | */ |
706 | int of_init_opp_table(struct device *dev) |
707 | { |
708 | const struct property *prop; |
709 | const __be32 *val; |
710 | int nr; |
711 | |
712 | prop = of_find_property(dev->of_node, "operating-points", NULL); |
713 | if (!prop) |
714 | return -ENODEV; |
715 | if (!prop->value) |
716 | return -ENODATA; |
717 | |
718 | /* |
719 | * Each OPP is a set of tuples consisting of frequency and |
720 | * voltage like <freq-kHz vol-uV>. |
721 | */ |
722 | nr = prop->length / sizeof(u32); |
723 | if (nr % 2) { |
724 | dev_err(dev, "%s: Invalid OPP list\n", __func__); |
725 | return -EINVAL; |
726 | } |
727 | |
728 | val = prop->value; |
729 | while (nr) { |
730 | unsigned long freq = be32_to_cpup(val++) * 1000; |
731 | unsigned long volt = be32_to_cpup(val++); |
732 | |
733 | if (opp_add(dev, freq, volt)) { |
734 | dev_warn(dev, "%s: Failed to add OPP %ld\n", |
735 | __func__, freq); |
736 | continue; |
737 | } |
738 | nr -= 2; |
739 | } |
740 | |
741 | return 0; |
742 | } |
743 | EXPORT_SYMBOL_GPL(of_init_opp_table); |
744 | #endif |
745 |
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