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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. | |
52 | * @available: true/false - marks if this OPP as available or not | |
53 | * @rate: Frequency in hertz | |
54 | * @u_volt: Nominal voltage in microvolts corresponding to this OPP | |
55 | * @dev_opp: points back to the device_opp struct this opp belongs to | |
cd1a068a | 56 | * @rcu_head: RCU callback head used for deferred freeing |
e1f60b29 NM |
57 | * |
58 | * This structure stores the OPP information for a given device. | |
59 | */ | |
47d43ba7 | 60 | struct dev_pm_opp { |
e1f60b29 NM |
61 | struct list_head node; |
62 | ||
63 | bool available; | |
64 | unsigned long rate; | |
65 | unsigned long u_volt; | |
66 | ||
67 | struct device_opp *dev_opp; | |
cd1a068a | 68 | struct rcu_head rcu_head; |
e1f60b29 NM |
69 | }; |
70 | ||
71 | /** | |
72 | * struct device_opp - Device opp structure | |
73 | * @node: list node - contains the devices with OPPs that | |
74 | * have been registered. Nodes once added are not modified in this | |
75 | * list. | |
76 | * RCU usage: nodes are not modified in the list of device_opp, | |
77 | * however addition is possible and is secured by dev_opp_list_lock | |
78 | * @dev: device pointer | |
cd1a068a | 79 | * @srcu_head: notifier head to notify the OPP availability changes. |
e1f60b29 NM |
80 | * @opp_list: list of opps |
81 | * | |
82 | * This is an internal data structure maintaining the link to opps attached to | |
83 | * a device. This structure is not meant to be shared to users as it is | |
84 | * meant for book keeping and private to OPP library | |
85 | */ | |
86 | struct device_opp { | |
87 | struct list_head node; | |
88 | ||
89 | struct device *dev; | |
cd1a068a | 90 | struct srcu_notifier_head srcu_head; |
e1f60b29 NM |
91 | struct list_head opp_list; |
92 | }; | |
93 | ||
94 | /* | |
95 | * The root of the list of all devices. All device_opp structures branch off | |
96 | * from here, with each device_opp containing the list of opp it supports in | |
97 | * various states of availability. | |
98 | */ | |
99 | static LIST_HEAD(dev_opp_list); | |
100 | /* Lock to allow exclusive modification to the device and opp lists */ | |
101 | static DEFINE_MUTEX(dev_opp_list_lock); | |
102 | ||
103 | /** | |
104 | * find_device_opp() - find device_opp struct using device pointer | |
105 | * @dev: device pointer used to lookup device OPPs | |
106 | * | |
107 | * Search list of device OPPs for one containing matching device. Does a RCU | |
108 | * reader operation to grab the pointer needed. | |
109 | * | |
110 | * Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or | |
111 | * -EINVAL based on type of error. | |
112 | * | |
113 | * Locking: This function must be called under rcu_read_lock(). device_opp | |
114 | * is a RCU protected pointer. This means that device_opp is valid as long | |
115 | * as we are under RCU lock. | |
116 | */ | |
117 | static struct device_opp *find_device_opp(struct device *dev) | |
118 | { | |
119 | struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV); | |
120 | ||
121 | if (unlikely(IS_ERR_OR_NULL(dev))) { | |
122 | pr_err("%s: Invalid parameters\n", __func__); | |
123 | return ERR_PTR(-EINVAL); | |
124 | } | |
125 | ||
126 | list_for_each_entry_rcu(tmp_dev_opp, &dev_opp_list, node) { | |
127 | if (tmp_dev_opp->dev == dev) { | |
128 | dev_opp = tmp_dev_opp; | |
129 | break; | |
130 | } | |
131 | } | |
132 | ||
133 | return dev_opp; | |
134 | } | |
135 | ||
136 | /** | |
5d4879cd | 137 | * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp |
e1f60b29 NM |
138 | * @opp: opp for which voltage has to be returned for |
139 | * | |
140 | * Return voltage in micro volt corresponding to the opp, else | |
141 | * return 0 | |
142 | * | |
143 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
144 | * protected pointer. This means that opp which could have been fetched by | |
145 | * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are | |
146 | * under RCU lock. The pointer returned by the opp_find_freq family must be | |
147 | * used in the same section as the usage of this function with the pointer | |
148 | * prior to unlocking with rcu_read_unlock() to maintain the integrity of the | |
149 | * pointer. | |
150 | */ | |
47d43ba7 | 151 | unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp) |
e1f60b29 | 152 | { |
47d43ba7 | 153 | struct dev_pm_opp *tmp_opp; |
e1f60b29 NM |
154 | unsigned long v = 0; |
155 | ||
156 | tmp_opp = rcu_dereference(opp); | |
157 | if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) | |
158 | pr_err("%s: Invalid parameters\n", __func__); | |
159 | else | |
160 | v = tmp_opp->u_volt; | |
161 | ||
162 | return v; | |
163 | } | |
5d4879cd | 164 | EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage); |
e1f60b29 NM |
165 | |
166 | /** | |
5d4879cd | 167 | * dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp |
e1f60b29 NM |
168 | * @opp: opp for which frequency has to be returned for |
169 | * | |
170 | * Return frequency in hertz corresponding to the opp, else | |
171 | * return 0 | |
172 | * | |
173 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
174 | * protected pointer. This means that opp which could have been fetched by | |
175 | * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are | |
176 | * under RCU lock. The pointer returned by the opp_find_freq family must be | |
177 | * used in the same section as the usage of this function with the pointer | |
178 | * prior to unlocking with rcu_read_unlock() to maintain the integrity of the | |
179 | * pointer. | |
180 | */ | |
47d43ba7 | 181 | unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp) |
e1f60b29 | 182 | { |
47d43ba7 | 183 | struct dev_pm_opp *tmp_opp; |
e1f60b29 NM |
184 | unsigned long f = 0; |
185 | ||
186 | tmp_opp = rcu_dereference(opp); | |
187 | if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) | |
188 | pr_err("%s: Invalid parameters\n", __func__); | |
189 | else | |
190 | f = tmp_opp->rate; | |
191 | ||
192 | return f; | |
193 | } | |
5d4879cd | 194 | EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq); |
e1f60b29 NM |
195 | |
196 | /** | |
5d4879cd | 197 | * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list |
e1f60b29 NM |
198 | * @dev: device for which we do this operation |
199 | * | |
200 | * This function returns the number of available opps if there are any, | |
201 | * else returns 0 if none or the corresponding error value. | |
202 | * | |
203 | * Locking: This function must be called under rcu_read_lock(). This function | |
204 | * internally references two RCU protected structures: device_opp and opp which | |
205 | * are safe as long as we are under a common RCU locked section. | |
206 | */ | |
5d4879cd | 207 | int dev_pm_opp_get_opp_count(struct device *dev) |
e1f60b29 NM |
208 | { |
209 | struct device_opp *dev_opp; | |
47d43ba7 | 210 | struct dev_pm_opp *temp_opp; |
e1f60b29 NM |
211 | int count = 0; |
212 | ||
213 | dev_opp = find_device_opp(dev); | |
214 | if (IS_ERR(dev_opp)) { | |
215 | int r = PTR_ERR(dev_opp); | |
216 | dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r); | |
217 | return r; | |
218 | } | |
219 | ||
220 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
221 | if (temp_opp->available) | |
222 | count++; | |
223 | } | |
224 | ||
225 | return count; | |
226 | } | |
5d4879cd | 227 | EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count); |
e1f60b29 NM |
228 | |
229 | /** | |
5d4879cd | 230 | * dev_pm_opp_find_freq_exact() - search for an exact frequency |
e1f60b29 NM |
231 | * @dev: device for which we do this operation |
232 | * @freq: frequency to search for | |
7ae49618 | 233 | * @available: true/false - match for available opp |
e1f60b29 NM |
234 | * |
235 | * Searches for exact match in the opp list and returns pointer to the matching | |
236 | * opp if found, else returns ERR_PTR in case of error and should be handled | |
0779726c NM |
237 | * using IS_ERR. Error return values can be: |
238 | * EINVAL: for bad pointer | |
239 | * ERANGE: no match found for search | |
240 | * ENODEV: if device not found in list of registered devices | |
e1f60b29 NM |
241 | * |
242 | * Note: available is a modifier for the search. if available=true, then the | |
243 | * match is for exact matching frequency and is available in the stored OPP | |
244 | * table. if false, the match is for exact frequency which is not available. | |
245 | * | |
246 | * This provides a mechanism to enable an opp which is not available currently | |
247 | * or the opposite as well. | |
248 | * | |
249 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
250 | * protected pointer. The reason for the same is that the opp pointer which is | |
251 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
252 | * under the locked area. The pointer returned must be used prior to unlocking | |
253 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
254 | */ | |
47d43ba7 NM |
255 | struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, |
256 | unsigned long freq, | |
257 | bool available) | |
e1f60b29 NM |
258 | { |
259 | struct device_opp *dev_opp; | |
47d43ba7 | 260 | struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
e1f60b29 NM |
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 | } | |
5d4879cd | 279 | EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact); |
e1f60b29 NM |
280 | |
281 | /** | |
5d4879cd | 282 | * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq |
e1f60b29 NM |
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 | |
0779726c NM |
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 | |
e1f60b29 NM |
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 | */ | |
47d43ba7 NM |
302 | struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev, |
303 | unsigned long *freq) | |
e1f60b29 NM |
304 | { |
305 | struct device_opp *dev_opp; | |
47d43ba7 | 306 | struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
e1f60b29 NM |
307 | |
308 | if (!dev || !freq) { | |
309 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); | |
310 | return ERR_PTR(-EINVAL); | |
311 | } | |
312 | ||
313 | dev_opp = find_device_opp(dev); | |
314 | if (IS_ERR(dev_opp)) | |
0779726c | 315 | return ERR_CAST(dev_opp); |
e1f60b29 NM |
316 | |
317 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
318 | if (temp_opp->available && temp_opp->rate >= *freq) { | |
319 | opp = temp_opp; | |
320 | *freq = opp->rate; | |
321 | break; | |
322 | } | |
323 | } | |
324 | ||
325 | return opp; | |
326 | } | |
5d4879cd | 327 | EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil); |
e1f60b29 NM |
328 | |
329 | /** | |
5d4879cd | 330 | * dev_pm_opp_find_freq_floor() - Search for a rounded floor freq |
e1f60b29 NM |
331 | * @dev: device for which we do this operation |
332 | * @freq: Start frequency | |
333 | * | |
334 | * Search for the matching floor *available* OPP from a starting freq | |
335 | * for a device. | |
336 | * | |
337 | * Returns matching *opp and refreshes *freq accordingly, else returns | |
0779726c NM |
338 | * ERR_PTR in case of error and should be handled using IS_ERR. Error return |
339 | * values can be: | |
340 | * EINVAL: for bad pointer | |
341 | * ERANGE: no match found for search | |
342 | * ENODEV: if device not found in list of registered devices | |
e1f60b29 NM |
343 | * |
344 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu | |
345 | * protected pointer. The reason for the same is that the opp pointer which is | |
346 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
347 | * under the locked area. The pointer returned must be used prior to unlocking | |
348 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
349 | */ | |
47d43ba7 NM |
350 | struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, |
351 | unsigned long *freq) | |
e1f60b29 NM |
352 | { |
353 | struct device_opp *dev_opp; | |
47d43ba7 | 354 | struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); |
e1f60b29 NM |
355 | |
356 | if (!dev || !freq) { | |
357 | dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); | |
358 | return ERR_PTR(-EINVAL); | |
359 | } | |
360 | ||
361 | dev_opp = find_device_opp(dev); | |
362 | if (IS_ERR(dev_opp)) | |
0779726c | 363 | return ERR_CAST(dev_opp); |
e1f60b29 NM |
364 | |
365 | list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) { | |
366 | if (temp_opp->available) { | |
367 | /* go to the next node, before choosing prev */ | |
368 | if (temp_opp->rate > *freq) | |
369 | break; | |
370 | else | |
371 | opp = temp_opp; | |
372 | } | |
373 | } | |
374 | if (!IS_ERR(opp)) | |
375 | *freq = opp->rate; | |
376 | ||
377 | return opp; | |
378 | } | |
5d4879cd | 379 | EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor); |
e1f60b29 NM |
380 | |
381 | /** | |
5d4879cd | 382 | * dev_pm_opp_add() - Add an OPP table from a table definitions |
e1f60b29 NM |
383 | * @dev: device for which we do this operation |
384 | * @freq: Frequency in Hz for this OPP | |
385 | * @u_volt: Voltage in uVolts for this OPP | |
386 | * | |
387 | * This function adds an opp definition to the opp list and returns status. | |
388 | * The opp is made available by default and it can be controlled using | |
5d4879cd | 389 | * dev_pm_opp_enable/disable functions. |
e1f60b29 NM |
390 | * |
391 | * Locking: The internal device_opp and opp structures are RCU protected. | |
392 | * Hence this function internally uses RCU updater strategy with mutex locks | |
393 | * to keep the integrity of the internal data structures. Callers should ensure | |
394 | * that this function is *NOT* called under RCU protection or in contexts where | |
395 | * mutex cannot be locked. | |
64ce8545 CK |
396 | * |
397 | * Return: | |
398 | * 0: On success OR | |
399 | * Duplicate OPPs (both freq and volt are same) and opp->available | |
400 | * -EEXIST: Freq are same and volt are different OR | |
401 | * Duplicate OPPs (both freq and volt are same) and !opp->available | |
402 | * -ENOMEM: Memory allocation failure | |
e1f60b29 | 403 | */ |
5d4879cd | 404 | int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) |
e1f60b29 NM |
405 | { |
406 | struct device_opp *dev_opp = NULL; | |
47d43ba7 | 407 | struct dev_pm_opp *opp, *new_opp; |
e1f60b29 NM |
408 | struct list_head *head; |
409 | ||
410 | /* allocate new OPP node */ | |
47d43ba7 | 411 | new_opp = kzalloc(sizeof(*new_opp), GFP_KERNEL); |
e1f60b29 NM |
412 | if (!new_opp) { |
413 | dev_warn(dev, "%s: Unable to create new OPP node\n", __func__); | |
414 | return -ENOMEM; | |
415 | } | |
416 | ||
417 | /* Hold our list modification lock here */ | |
418 | mutex_lock(&dev_opp_list_lock); | |
419 | ||
a7470db6 VK |
420 | /* populate the opp table */ |
421 | new_opp->dev_opp = dev_opp; | |
422 | new_opp->rate = freq; | |
423 | new_opp->u_volt = u_volt; | |
424 | new_opp->available = true; | |
425 | ||
e1f60b29 NM |
426 | /* Check for existing list for 'dev' */ |
427 | dev_opp = find_device_opp(dev); | |
428 | if (IS_ERR(dev_opp)) { | |
429 | /* | |
430 | * Allocate a new device OPP table. In the infrequent case | |
431 | * where a new device is needed to be added, we pay this | |
432 | * penalty. | |
433 | */ | |
434 | dev_opp = kzalloc(sizeof(struct device_opp), GFP_KERNEL); | |
435 | if (!dev_opp) { | |
436 | mutex_unlock(&dev_opp_list_lock); | |
437 | kfree(new_opp); | |
438 | dev_warn(dev, | |
439 | "%s: Unable to create device OPP structure\n", | |
440 | __func__); | |
441 | return -ENOMEM; | |
442 | } | |
443 | ||
444 | dev_opp->dev = dev; | |
cd1a068a | 445 | srcu_init_notifier_head(&dev_opp->srcu_head); |
e1f60b29 NM |
446 | INIT_LIST_HEAD(&dev_opp->opp_list); |
447 | ||
448 | /* Secure the device list modification */ | |
449 | list_add_rcu(&dev_opp->node, &dev_opp_list); | |
a7470db6 VK |
450 | head = &dev_opp->opp_list; |
451 | goto list_add; | |
e1f60b29 NM |
452 | } |
453 | ||
64ce8545 CK |
454 | /* |
455 | * Insert new OPP in order of increasing frequency | |
456 | * and discard if already present | |
457 | */ | |
e1f60b29 NM |
458 | head = &dev_opp->opp_list; |
459 | list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) { | |
64ce8545 | 460 | if (new_opp->rate <= opp->rate) |
e1f60b29 NM |
461 | break; |
462 | else | |
463 | head = &opp->node; | |
464 | } | |
465 | ||
64ce8545 CK |
466 | /* Duplicate OPPs ? */ |
467 | if (new_opp->rate == opp->rate) { | |
468 | int ret = opp->available && new_opp->u_volt == opp->u_volt ? | |
469 | 0 : -EEXIST; | |
470 | ||
471 | dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n", | |
472 | __func__, opp->rate, opp->u_volt, opp->available, | |
473 | new_opp->rate, new_opp->u_volt, new_opp->available); | |
474 | mutex_unlock(&dev_opp_list_lock); | |
475 | kfree(new_opp); | |
476 | return ret; | |
477 | } | |
478 | ||
a7470db6 | 479 | list_add: |
e1f60b29 NM |
480 | list_add_rcu(&new_opp->node, head); |
481 | mutex_unlock(&dev_opp_list_lock); | |
482 | ||
03ca370f MH |
483 | /* |
484 | * Notify the changes in the availability of the operable | |
485 | * frequency/voltage list. | |
486 | */ | |
cd1a068a | 487 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp); |
e1f60b29 NM |
488 | return 0; |
489 | } | |
5d4879cd | 490 | EXPORT_SYMBOL_GPL(dev_pm_opp_add); |
e1f60b29 NM |
491 | |
492 | /** | |
493 | * opp_set_availability() - helper to set the availability of an opp | |
494 | * @dev: device for which we do this operation | |
495 | * @freq: OPP frequency to modify availability | |
496 | * @availability_req: availability status requested for this opp | |
497 | * | |
498 | * Set the availability of an OPP with an RCU operation, opp_{enable,disable} | |
499 | * share a common logic which is isolated here. | |
500 | * | |
501 | * Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the | |
502 | * copy operation, returns 0 if no modifcation was done OR modification was | |
503 | * successful. | |
504 | * | |
505 | * Locking: The internal device_opp and opp structures are RCU protected. | |
506 | * Hence this function internally uses RCU updater strategy with mutex locks to | |
507 | * keep the integrity of the internal data structures. Callers should ensure | |
508 | * that this function is *NOT* called under RCU protection or in contexts where | |
509 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
510 | */ | |
511 | static int opp_set_availability(struct device *dev, unsigned long freq, | |
512 | bool availability_req) | |
513 | { | |
fc92805a | 514 | struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV); |
47d43ba7 | 515 | struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV); |
e1f60b29 NM |
516 | int r = 0; |
517 | ||
518 | /* keep the node allocated */ | |
47d43ba7 | 519 | new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL); |
e1f60b29 NM |
520 | if (!new_opp) { |
521 | dev_warn(dev, "%s: Unable to create OPP\n", __func__); | |
522 | return -ENOMEM; | |
523 | } | |
524 | ||
525 | mutex_lock(&dev_opp_list_lock); | |
526 | ||
527 | /* Find the device_opp */ | |
528 | list_for_each_entry(tmp_dev_opp, &dev_opp_list, node) { | |
529 | if (dev == tmp_dev_opp->dev) { | |
530 | dev_opp = tmp_dev_opp; | |
531 | break; | |
532 | } | |
533 | } | |
534 | if (IS_ERR(dev_opp)) { | |
535 | r = PTR_ERR(dev_opp); | |
536 | dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r); | |
537 | goto unlock; | |
538 | } | |
539 | ||
540 | /* Do we have the frequency? */ | |
541 | list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) { | |
542 | if (tmp_opp->rate == freq) { | |
543 | opp = tmp_opp; | |
544 | break; | |
545 | } | |
546 | } | |
547 | if (IS_ERR(opp)) { | |
548 | r = PTR_ERR(opp); | |
549 | goto unlock; | |
550 | } | |
551 | ||
552 | /* Is update really needed? */ | |
553 | if (opp->available == availability_req) | |
554 | goto unlock; | |
555 | /* copy the old data over */ | |
556 | *new_opp = *opp; | |
557 | ||
558 | /* plug in new node */ | |
559 | new_opp->available = availability_req; | |
560 | ||
561 | list_replace_rcu(&opp->node, &new_opp->node); | |
562 | mutex_unlock(&dev_opp_list_lock); | |
cd1a068a | 563 | kfree_rcu(opp, rcu_head); |
e1f60b29 | 564 | |
03ca370f MH |
565 | /* Notify the change of the OPP availability */ |
566 | if (availability_req) | |
cd1a068a | 567 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ENABLE, |
03ca370f MH |
568 | new_opp); |
569 | else | |
cd1a068a | 570 | srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_DISABLE, |
03ca370f MH |
571 | new_opp); |
572 | ||
dde8437d | 573 | return 0; |
e1f60b29 NM |
574 | |
575 | unlock: | |
576 | mutex_unlock(&dev_opp_list_lock); | |
e1f60b29 NM |
577 | kfree(new_opp); |
578 | return r; | |
579 | } | |
580 | ||
581 | /** | |
5d4879cd | 582 | * dev_pm_opp_enable() - Enable a specific OPP |
e1f60b29 NM |
583 | * @dev: device for which we do this operation |
584 | * @freq: OPP frequency to enable | |
585 | * | |
586 | * Enables a provided opp. If the operation is valid, this returns 0, else the | |
587 | * corresponding error value. It is meant to be used for users an OPP available | |
5d4879cd | 588 | * after being temporarily made unavailable with dev_pm_opp_disable. |
e1f60b29 NM |
589 | * |
590 | * Locking: The internal device_opp and opp structures are RCU protected. | |
591 | * Hence this function indirectly uses RCU and mutex locks to keep the | |
592 | * integrity of the internal data structures. Callers should ensure that | |
593 | * this function is *NOT* called under RCU protection or in contexts where | |
594 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
595 | */ | |
5d4879cd | 596 | int dev_pm_opp_enable(struct device *dev, unsigned long freq) |
e1f60b29 NM |
597 | { |
598 | return opp_set_availability(dev, freq, true); | |
599 | } | |
5d4879cd | 600 | EXPORT_SYMBOL_GPL(dev_pm_opp_enable); |
e1f60b29 NM |
601 | |
602 | /** | |
5d4879cd | 603 | * dev_pm_opp_disable() - Disable a specific OPP |
e1f60b29 NM |
604 | * @dev: device for which we do this operation |
605 | * @freq: OPP frequency to disable | |
606 | * | |
607 | * Disables a provided opp. If the operation is valid, this returns | |
608 | * 0, else the corresponding error value. It is meant to be a temporary | |
609 | * control by users to make this OPP not available until the circumstances are | |
5d4879cd | 610 | * right to make it available again (with a call to dev_pm_opp_enable). |
e1f60b29 NM |
611 | * |
612 | * Locking: The internal device_opp and opp structures are RCU protected. | |
613 | * Hence this function indirectly uses RCU and mutex locks to keep the | |
614 | * integrity of the internal data structures. Callers should ensure that | |
615 | * this function is *NOT* called under RCU protection or in contexts where | |
616 | * mutex locking or synchronize_rcu() blocking calls cannot be used. | |
617 | */ | |
5d4879cd | 618 | int dev_pm_opp_disable(struct device *dev, unsigned long freq) |
e1f60b29 NM |
619 | { |
620 | return opp_set_availability(dev, freq, false); | |
621 | } | |
5d4879cd | 622 | EXPORT_SYMBOL_GPL(dev_pm_opp_disable); |
e1f60b29 | 623 | |
03ca370f | 624 | /** |
5d4879cd | 625 | * dev_pm_opp_get_notifier() - find notifier_head of the device with opp |
03ca370f MH |
626 | * @dev: device pointer used to lookup device OPPs. |
627 | */ | |
5d4879cd | 628 | struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev) |
03ca370f MH |
629 | { |
630 | struct device_opp *dev_opp = find_device_opp(dev); | |
631 | ||
632 | if (IS_ERR(dev_opp)) | |
156acb16 | 633 | return ERR_CAST(dev_opp); /* matching type */ |
03ca370f | 634 | |
cd1a068a | 635 | return &dev_opp->srcu_head; |
03ca370f | 636 | } |
b496dfbc SG |
637 | |
638 | #ifdef CONFIG_OF | |
639 | /** | |
640 | * of_init_opp_table() - Initialize opp table from device tree | |
641 | * @dev: device pointer used to lookup device OPPs. | |
642 | * | |
643 | * Register the initial OPP table with the OPP library for given device. | |
644 | */ | |
645 | int of_init_opp_table(struct device *dev) | |
646 | { | |
647 | const struct property *prop; | |
648 | const __be32 *val; | |
649 | int nr; | |
650 | ||
651 | prop = of_find_property(dev->of_node, "operating-points", NULL); | |
652 | if (!prop) | |
653 | return -ENODEV; | |
654 | if (!prop->value) | |
655 | return -ENODATA; | |
656 | ||
657 | /* | |
658 | * Each OPP is a set of tuples consisting of frequency and | |
659 | * voltage like <freq-kHz vol-uV>. | |
660 | */ | |
661 | nr = prop->length / sizeof(u32); | |
662 | if (nr % 2) { | |
663 | dev_err(dev, "%s: Invalid OPP list\n", __func__); | |
664 | return -EINVAL; | |
665 | } | |
666 | ||
667 | val = prop->value; | |
668 | while (nr) { | |
669 | unsigned long freq = be32_to_cpup(val++) * 1000; | |
670 | unsigned long volt = be32_to_cpup(val++); | |
671 | ||
086abb58 | 672 | if (dev_pm_opp_add(dev, freq, volt)) |
b496dfbc SG |
673 | dev_warn(dev, "%s: Failed to add OPP %ld\n", |
674 | __func__, freq); | |
b496dfbc SG |
675 | nr -= 2; |
676 | } | |
677 | ||
678 | return 0; | |
679 | } | |
74c46c6e | 680 | EXPORT_SYMBOL_GPL(of_init_opp_table); |
b496dfbc | 681 | #endif |