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bd9a4c7d OBC |
1 | /* |
2 | * Hardware spinlock framework | |
3 | * | |
4 | * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com | |
5 | * | |
6 | * Contact: Ohad Ben-Cohen <ohad@wizery.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License version 2 as published | |
10 | * by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | */ | |
17 | ||
18 | #define pr_fmt(fmt) "%s: " fmt, __func__ | |
19 | ||
20 | #include <linux/kernel.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/types.h> | |
24 | #include <linux/err.h> | |
25 | #include <linux/jiffies.h> | |
26 | #include <linux/radix-tree.h> | |
27 | #include <linux/hwspinlock.h> | |
28 | #include <linux/pm_runtime.h> | |
93b465c2 | 29 | #include <linux/mutex.h> |
bd9a4c7d OBC |
30 | |
31 | #include "hwspinlock_internal.h" | |
32 | ||
33 | /* radix tree tags */ | |
34 | #define HWSPINLOCK_UNUSED (0) /* tags an hwspinlock as unused */ | |
35 | ||
36 | /* | |
37 | * A radix tree is used to maintain the available hwspinlock instances. | |
38 | * The tree associates hwspinlock pointers with their integer key id, | |
39 | * and provides easy-to-use API which makes the hwspinlock core code simple | |
40 | * and easy to read. | |
41 | * | |
42 | * Radix trees are quick on lookups, and reasonably efficient in terms of | |
43 | * storage, especially with high density usages such as this framework | |
44 | * requires (a continuous range of integer keys, beginning with zero, is | |
45 | * used as the ID's of the hwspinlock instances). | |
46 | * | |
47 | * The radix tree API supports tagging items in the tree, which this | |
48 | * framework uses to mark unused hwspinlock instances (see the | |
49 | * HWSPINLOCK_UNUSED tag above). As a result, the process of querying the | |
50 | * tree, looking for an unused hwspinlock instance, is now reduced to a | |
51 | * single radix tree API call. | |
52 | */ | |
53 | static RADIX_TREE(hwspinlock_tree, GFP_KERNEL); | |
54 | ||
55 | /* | |
93b465c2 | 56 | * Synchronization of access to the tree is achieved using this mutex, |
bd9a4c7d | 57 | * as the radix-tree API requires that users provide all synchronisation. |
93b465c2 | 58 | * A mutex is needed because we're using non-atomic radix tree allocations. |
bd9a4c7d | 59 | */ |
93b465c2 JG |
60 | static DEFINE_MUTEX(hwspinlock_tree_lock); |
61 | ||
bd9a4c7d OBC |
62 | |
63 | /** | |
64 | * __hwspin_trylock() - attempt to lock a specific hwspinlock | |
65 | * @hwlock: an hwspinlock which we want to trylock | |
66 | * @mode: controls whether local interrupts are disabled or not | |
67 | * @flags: a pointer where the caller's interrupt state will be saved at (if | |
68 | * requested) | |
69 | * | |
70 | * This function attempts to lock an hwspinlock, and will immediately | |
71 | * fail if the hwspinlock is already taken. | |
72 | * | |
73 | * Upon a successful return from this function, preemption (and possibly | |
74 | * interrupts) is disabled, so the caller must not sleep, and is advised to | |
75 | * release the hwspinlock as soon as possible. This is required in order to | |
76 | * minimize remote cores polling on the hardware interconnect. | |
77 | * | |
78 | * The user decides whether local interrupts are disabled or not, and if yes, | |
79 | * whether he wants their previous state to be saved. It is up to the user | |
80 | * to choose the appropriate @mode of operation, exactly the same way users | |
81 | * should decide between spin_trylock, spin_trylock_irq and | |
82 | * spin_trylock_irqsave. | |
83 | * | |
84 | * Returns 0 if we successfully locked the hwspinlock or -EBUSY if | |
85 | * the hwspinlock was already taken. | |
86 | * This function will never sleep. | |
87 | */ | |
88 | int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) | |
89 | { | |
90 | int ret; | |
91 | ||
92 | BUG_ON(!hwlock); | |
93 | BUG_ON(!flags && mode == HWLOCK_IRQSTATE); | |
94 | ||
95 | /* | |
96 | * This spin_lock{_irq, _irqsave} serves three purposes: | |
97 | * | |
98 | * 1. Disable preemption, in order to minimize the period of time | |
99 | * in which the hwspinlock is taken. This is important in order | |
100 | * to minimize the possible polling on the hardware interconnect | |
101 | * by a remote user of this lock. | |
102 | * 2. Make the hwspinlock SMP-safe (so we can take it from | |
103 | * additional contexts on the local host). | |
104 | * 3. Ensure that in_atomic/might_sleep checks catch potential | |
105 | * problems with hwspinlock usage (e.g. scheduler checks like | |
106 | * 'scheduling while atomic' etc.) | |
107 | */ | |
108 | if (mode == HWLOCK_IRQSTATE) | |
109 | ret = spin_trylock_irqsave(&hwlock->lock, *flags); | |
110 | else if (mode == HWLOCK_IRQ) | |
111 | ret = spin_trylock_irq(&hwlock->lock); | |
112 | else | |
113 | ret = spin_trylock(&hwlock->lock); | |
114 | ||
115 | /* is lock already taken by another context on the local cpu ? */ | |
116 | if (!ret) | |
117 | return -EBUSY; | |
118 | ||
119 | /* try to take the hwspinlock device */ | |
120 | ret = hwlock->ops->trylock(hwlock); | |
121 | ||
122 | /* if hwlock is already taken, undo spin_trylock_* and exit */ | |
123 | if (!ret) { | |
124 | if (mode == HWLOCK_IRQSTATE) | |
125 | spin_unlock_irqrestore(&hwlock->lock, *flags); | |
126 | else if (mode == HWLOCK_IRQ) | |
127 | spin_unlock_irq(&hwlock->lock); | |
128 | else | |
129 | spin_unlock(&hwlock->lock); | |
130 | ||
131 | return -EBUSY; | |
132 | } | |
133 | ||
134 | /* | |
135 | * We can be sure the other core's memory operations | |
136 | * are observable to us only _after_ we successfully take | |
137 | * the hwspinlock, and we must make sure that subsequent memory | |
138 | * operations (both reads and writes) will not be reordered before | |
139 | * we actually took the hwspinlock. | |
140 | * | |
141 | * Note: the implicit memory barrier of the spinlock above is too | |
142 | * early, so we need this additional explicit memory barrier. | |
143 | */ | |
144 | mb(); | |
145 | ||
146 | return 0; | |
147 | } | |
148 | EXPORT_SYMBOL_GPL(__hwspin_trylock); | |
149 | ||
150 | /** | |
151 | * __hwspin_lock_timeout() - lock an hwspinlock with timeout limit | |
152 | * @hwlock: the hwspinlock to be locked | |
153 | * @timeout: timeout value in msecs | |
154 | * @mode: mode which controls whether local interrupts are disabled or not | |
155 | * @flags: a pointer to where the caller's interrupt state will be saved at (if | |
156 | * requested) | |
157 | * | |
158 | * This function locks the given @hwlock. If the @hwlock | |
159 | * is already taken, the function will busy loop waiting for it to | |
160 | * be released, but give up after @timeout msecs have elapsed. | |
161 | * | |
162 | * Upon a successful return from this function, preemption is disabled | |
163 | * (and possibly local interrupts, too), so the caller must not sleep, | |
164 | * and is advised to release the hwspinlock as soon as possible. | |
165 | * This is required in order to minimize remote cores polling on the | |
166 | * hardware interconnect. | |
167 | * | |
168 | * The user decides whether local interrupts are disabled or not, and if yes, | |
169 | * whether he wants their previous state to be saved. It is up to the user | |
170 | * to choose the appropriate @mode of operation, exactly the same way users | |
171 | * should decide between spin_lock, spin_lock_irq and spin_lock_irqsave. | |
172 | * | |
173 | * Returns 0 when the @hwlock was successfully taken, and an appropriate | |
174 | * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still | |
175 | * busy after @timeout msecs). The function will never sleep. | |
176 | */ | |
177 | int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to, | |
178 | int mode, unsigned long *flags) | |
179 | { | |
180 | int ret; | |
181 | unsigned long expire; | |
182 | ||
183 | expire = msecs_to_jiffies(to) + jiffies; | |
184 | ||
185 | for (;;) { | |
186 | /* Try to take the hwspinlock */ | |
187 | ret = __hwspin_trylock(hwlock, mode, flags); | |
188 | if (ret != -EBUSY) | |
189 | break; | |
190 | ||
191 | /* | |
192 | * The lock is already taken, let's check if the user wants | |
193 | * us to try again | |
194 | */ | |
195 | if (time_is_before_eq_jiffies(expire)) | |
196 | return -ETIMEDOUT; | |
197 | ||
198 | /* | |
199 | * Allow platform-specific relax handlers to prevent | |
200 | * hogging the interconnect (no sleeping, though) | |
201 | */ | |
202 | if (hwlock->ops->relax) | |
203 | hwlock->ops->relax(hwlock); | |
204 | } | |
205 | ||
206 | return ret; | |
207 | } | |
208 | EXPORT_SYMBOL_GPL(__hwspin_lock_timeout); | |
209 | ||
210 | /** | |
211 | * __hwspin_unlock() - unlock a specific hwspinlock | |
212 | * @hwlock: a previously-acquired hwspinlock which we want to unlock | |
213 | * @mode: controls whether local interrupts needs to be restored or not | |
214 | * @flags: previous caller's interrupt state to restore (if requested) | |
215 | * | |
216 | * This function will unlock a specific hwspinlock, enable preemption and | |
217 | * (possibly) enable interrupts or restore their previous state. | |
218 | * @hwlock must be already locked before calling this function: it is a bug | |
219 | * to call unlock on a @hwlock that is already unlocked. | |
220 | * | |
221 | * The user decides whether local interrupts should be enabled or not, and | |
222 | * if yes, whether he wants their previous state to be restored. It is up | |
223 | * to the user to choose the appropriate @mode of operation, exactly the | |
224 | * same way users decide between spin_unlock, spin_unlock_irq and | |
225 | * spin_unlock_irqrestore. | |
226 | * | |
227 | * The function will never sleep. | |
228 | */ | |
229 | void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) | |
230 | { | |
231 | BUG_ON(!hwlock); | |
232 | BUG_ON(!flags && mode == HWLOCK_IRQSTATE); | |
233 | ||
234 | /* | |
235 | * We must make sure that memory operations (both reads and writes), | |
236 | * done before unlocking the hwspinlock, will not be reordered | |
237 | * after the lock is released. | |
238 | * | |
239 | * That's the purpose of this explicit memory barrier. | |
240 | * | |
241 | * Note: the memory barrier induced by the spin_unlock below is too | |
242 | * late; the other core is going to access memory soon after it will | |
243 | * take the hwspinlock, and by then we want to be sure our memory | |
244 | * operations are already observable. | |
245 | */ | |
246 | mb(); | |
247 | ||
248 | hwlock->ops->unlock(hwlock); | |
249 | ||
250 | /* Undo the spin_trylock{_irq, _irqsave} called while locking */ | |
251 | if (mode == HWLOCK_IRQSTATE) | |
252 | spin_unlock_irqrestore(&hwlock->lock, *flags); | |
253 | else if (mode == HWLOCK_IRQ) | |
254 | spin_unlock_irq(&hwlock->lock); | |
255 | else | |
256 | spin_unlock(&hwlock->lock); | |
257 | } | |
258 | EXPORT_SYMBOL_GPL(__hwspin_unlock); | |
259 | ||
260 | /** | |
261 | * hwspin_lock_register() - register a new hw spinlock | |
262 | * @hwlock: hwspinlock to register. | |
263 | * | |
264 | * This function should be called from the underlying platform-specific | |
265 | * implementation, to register a new hwspinlock instance. | |
266 | * | |
93b465c2 | 267 | * Should be called from a process context (might sleep) |
bd9a4c7d OBC |
268 | * |
269 | * Returns 0 on success, or an appropriate error code on failure | |
270 | */ | |
271 | int hwspin_lock_register(struct hwspinlock *hwlock) | |
272 | { | |
273 | struct hwspinlock *tmp; | |
274 | int ret; | |
275 | ||
276 | if (!hwlock || !hwlock->ops || | |
277 | !hwlock->ops->trylock || !hwlock->ops->unlock) { | |
278 | pr_err("invalid parameters\n"); | |
279 | return -EINVAL; | |
280 | } | |
281 | ||
282 | spin_lock_init(&hwlock->lock); | |
283 | ||
93b465c2 | 284 | mutex_lock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
285 | |
286 | ret = radix_tree_insert(&hwspinlock_tree, hwlock->id, hwlock); | |
c3c1250e OBC |
287 | if (ret == -EEXIST) |
288 | pr_err("hwspinlock id %d already exists!\n", hwlock->id); | |
bd9a4c7d OBC |
289 | if (ret) |
290 | goto out; | |
291 | ||
292 | /* mark this hwspinlock as available */ | |
293 | tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock->id, | |
294 | HWSPINLOCK_UNUSED); | |
295 | ||
296 | /* self-sanity check which should never fail */ | |
297 | WARN_ON(tmp != hwlock); | |
298 | ||
299 | out: | |
93b465c2 | 300 | mutex_unlock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
301 | return ret; |
302 | } | |
303 | EXPORT_SYMBOL_GPL(hwspin_lock_register); | |
304 | ||
305 | /** | |
306 | * hwspin_lock_unregister() - unregister an hw spinlock | |
307 | * @id: index of the specific hwspinlock to unregister | |
308 | * | |
309 | * This function should be called from the underlying platform-specific | |
310 | * implementation, to unregister an existing (and unused) hwspinlock. | |
311 | * | |
93b465c2 | 312 | * Should be called from a process context (might sleep) |
bd9a4c7d OBC |
313 | * |
314 | * Returns the address of hwspinlock @id on success, or NULL on failure | |
315 | */ | |
316 | struct hwspinlock *hwspin_lock_unregister(unsigned int id) | |
317 | { | |
318 | struct hwspinlock *hwlock = NULL; | |
319 | int ret; | |
320 | ||
93b465c2 | 321 | mutex_lock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
322 | |
323 | /* make sure the hwspinlock is not in use (tag is set) */ | |
324 | ret = radix_tree_tag_get(&hwspinlock_tree, id, HWSPINLOCK_UNUSED); | |
325 | if (ret == 0) { | |
326 | pr_err("hwspinlock %d still in use (or not present)\n", id); | |
327 | goto out; | |
328 | } | |
329 | ||
330 | hwlock = radix_tree_delete(&hwspinlock_tree, id); | |
331 | if (!hwlock) { | |
332 | pr_err("failed to delete hwspinlock %d\n", id); | |
333 | goto out; | |
334 | } | |
335 | ||
336 | out: | |
93b465c2 | 337 | mutex_unlock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
338 | return hwlock; |
339 | } | |
340 | EXPORT_SYMBOL_GPL(hwspin_lock_unregister); | |
341 | ||
342 | /** | |
343 | * __hwspin_lock_request() - tag an hwspinlock as used and power it up | |
344 | * | |
345 | * This is an internal function that prepares an hwspinlock instance | |
346 | * before it is given to the user. The function assumes that | |
347 | * hwspinlock_tree_lock is taken. | |
348 | * | |
349 | * Returns 0 or positive to indicate success, and a negative value to | |
350 | * indicate an error (with the appropriate error code) | |
351 | */ | |
352 | static int __hwspin_lock_request(struct hwspinlock *hwlock) | |
353 | { | |
354 | struct hwspinlock *tmp; | |
355 | int ret; | |
356 | ||
357 | /* prevent underlying implementation from being removed */ | |
e467b642 | 358 | if (!try_module_get(hwlock->dev->driver->owner)) { |
bd9a4c7d OBC |
359 | dev_err(hwlock->dev, "%s: can't get owner\n", __func__); |
360 | return -EINVAL; | |
361 | } | |
362 | ||
363 | /* notify PM core that power is now needed */ | |
364 | ret = pm_runtime_get_sync(hwlock->dev); | |
365 | if (ret < 0) { | |
366 | dev_err(hwlock->dev, "%s: can't power on device\n", __func__); | |
367 | return ret; | |
368 | } | |
369 | ||
370 | /* mark hwspinlock as used, should not fail */ | |
371 | tmp = radix_tree_tag_clear(&hwspinlock_tree, hwlock->id, | |
372 | HWSPINLOCK_UNUSED); | |
373 | ||
374 | /* self-sanity check that should never fail */ | |
375 | WARN_ON(tmp != hwlock); | |
376 | ||
377 | return ret; | |
378 | } | |
379 | ||
380 | /** | |
381 | * hwspin_lock_get_id() - retrieve id number of a given hwspinlock | |
382 | * @hwlock: a valid hwspinlock instance | |
383 | * | |
384 | * Returns the id number of a given @hwlock, or -EINVAL if @hwlock is invalid. | |
385 | */ | |
386 | int hwspin_lock_get_id(struct hwspinlock *hwlock) | |
387 | { | |
388 | if (!hwlock) { | |
389 | pr_err("invalid hwlock\n"); | |
390 | return -EINVAL; | |
391 | } | |
392 | ||
393 | return hwlock->id; | |
394 | } | |
395 | EXPORT_SYMBOL_GPL(hwspin_lock_get_id); | |
396 | ||
397 | /** | |
398 | * hwspin_lock_request() - request an hwspinlock | |
399 | * | |
400 | * This function should be called by users of the hwspinlock device, | |
401 | * in order to dynamically assign them an unused hwspinlock. | |
402 | * Usually the user of this lock will then have to communicate the lock's id | |
403 | * to the remote core before it can be used for synchronization (to get the | |
404 | * id of a given hwlock, use hwspin_lock_get_id()). | |
405 | * | |
93b465c2 | 406 | * Should be called from a process context (might sleep) |
bd9a4c7d OBC |
407 | * |
408 | * Returns the address of the assigned hwspinlock, or NULL on error | |
409 | */ | |
410 | struct hwspinlock *hwspin_lock_request(void) | |
411 | { | |
412 | struct hwspinlock *hwlock; | |
413 | int ret; | |
414 | ||
93b465c2 | 415 | mutex_lock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
416 | |
417 | /* look for an unused lock */ | |
418 | ret = radix_tree_gang_lookup_tag(&hwspinlock_tree, (void **)&hwlock, | |
419 | 0, 1, HWSPINLOCK_UNUSED); | |
420 | if (ret == 0) { | |
421 | pr_warn("a free hwspinlock is not available\n"); | |
422 | hwlock = NULL; | |
423 | goto out; | |
424 | } | |
425 | ||
426 | /* sanity check that should never fail */ | |
427 | WARN_ON(ret > 1); | |
428 | ||
429 | /* mark as used and power up */ | |
430 | ret = __hwspin_lock_request(hwlock); | |
431 | if (ret < 0) | |
432 | hwlock = NULL; | |
433 | ||
434 | out: | |
93b465c2 | 435 | mutex_unlock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
436 | return hwlock; |
437 | } | |
438 | EXPORT_SYMBOL_GPL(hwspin_lock_request); | |
439 | ||
440 | /** | |
441 | * hwspin_lock_request_specific() - request for a specific hwspinlock | |
442 | * @id: index of the specific hwspinlock that is requested | |
443 | * | |
444 | * This function should be called by users of the hwspinlock module, | |
445 | * in order to assign them a specific hwspinlock. | |
446 | * Usually early board code will be calling this function in order to | |
447 | * reserve specific hwspinlock ids for predefined purposes. | |
448 | * | |
93b465c2 | 449 | * Should be called from a process context (might sleep) |
bd9a4c7d OBC |
450 | * |
451 | * Returns the address of the assigned hwspinlock, or NULL on error | |
452 | */ | |
453 | struct hwspinlock *hwspin_lock_request_specific(unsigned int id) | |
454 | { | |
455 | struct hwspinlock *hwlock; | |
456 | int ret; | |
457 | ||
93b465c2 | 458 | mutex_lock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
459 | |
460 | /* make sure this hwspinlock exists */ | |
461 | hwlock = radix_tree_lookup(&hwspinlock_tree, id); | |
462 | if (!hwlock) { | |
463 | pr_warn("hwspinlock %u does not exist\n", id); | |
464 | goto out; | |
465 | } | |
466 | ||
467 | /* sanity check (this shouldn't happen) */ | |
468 | WARN_ON(hwlock->id != id); | |
469 | ||
470 | /* make sure this hwspinlock is unused */ | |
471 | ret = radix_tree_tag_get(&hwspinlock_tree, id, HWSPINLOCK_UNUSED); | |
472 | if (ret == 0) { | |
473 | pr_warn("hwspinlock %u is already in use\n", id); | |
474 | hwlock = NULL; | |
475 | goto out; | |
476 | } | |
477 | ||
478 | /* mark as used and power up */ | |
479 | ret = __hwspin_lock_request(hwlock); | |
480 | if (ret < 0) | |
481 | hwlock = NULL; | |
482 | ||
483 | out: | |
93b465c2 | 484 | mutex_unlock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
485 | return hwlock; |
486 | } | |
487 | EXPORT_SYMBOL_GPL(hwspin_lock_request_specific); | |
488 | ||
489 | /** | |
490 | * hwspin_lock_free() - free a specific hwspinlock | |
491 | * @hwlock: the specific hwspinlock to free | |
492 | * | |
493 | * This function mark @hwlock as free again. | |
494 | * Should only be called with an @hwlock that was retrieved from | |
495 | * an earlier call to omap_hwspin_lock_request{_specific}. | |
496 | * | |
93b465c2 | 497 | * Should be called from a process context (might sleep) |
bd9a4c7d OBC |
498 | * |
499 | * Returns 0 on success, or an appropriate error code on failure | |
500 | */ | |
501 | int hwspin_lock_free(struct hwspinlock *hwlock) | |
502 | { | |
503 | struct hwspinlock *tmp; | |
504 | int ret; | |
505 | ||
506 | if (!hwlock) { | |
507 | pr_err("invalid hwlock\n"); | |
508 | return -EINVAL; | |
509 | } | |
510 | ||
93b465c2 | 511 | mutex_lock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
512 | |
513 | /* make sure the hwspinlock is used */ | |
514 | ret = radix_tree_tag_get(&hwspinlock_tree, hwlock->id, | |
515 | HWSPINLOCK_UNUSED); | |
516 | if (ret == 1) { | |
517 | dev_err(hwlock->dev, "%s: hwlock is already free\n", __func__); | |
518 | dump_stack(); | |
519 | ret = -EINVAL; | |
520 | goto out; | |
521 | } | |
522 | ||
523 | /* notify the underlying device that power is not needed */ | |
524 | ret = pm_runtime_put(hwlock->dev); | |
525 | if (ret < 0) | |
526 | goto out; | |
527 | ||
528 | /* mark this hwspinlock as available */ | |
529 | tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock->id, | |
530 | HWSPINLOCK_UNUSED); | |
531 | ||
532 | /* sanity check (this shouldn't happen) */ | |
533 | WARN_ON(tmp != hwlock); | |
534 | ||
e467b642 | 535 | module_put(hwlock->dev->driver->owner); |
bd9a4c7d OBC |
536 | |
537 | out: | |
93b465c2 | 538 | mutex_unlock(&hwspinlock_tree_lock); |
bd9a4c7d OBC |
539 | return ret; |
540 | } | |
541 | EXPORT_SYMBOL_GPL(hwspin_lock_free); | |
542 | ||
543 | MODULE_LICENSE("GPL v2"); | |
544 | MODULE_DESCRIPTION("Hardware spinlock interface"); | |
545 | MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>"); |