1 // SPDX-License-Identifier: GPL-2.0
3 * Hardware spinlock framework
5 * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
7 * Contact: Ohad Ben-Cohen <ohad@wizery.com>
10 #define pr_fmt(fmt) "%s: " fmt, __func__
12 #include <linux/delay.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/spinlock.h>
16 #include <linux/types.h>
17 #include <linux/err.h>
18 #include <linux/jiffies.h>
19 #include <linux/radix-tree.h>
20 #include <linux/hwspinlock.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/mutex.h>
25 #include "hwspinlock_internal.h"
27 /* retry delay used in atomic context */
28 #define HWSPINLOCK_RETRY_DELAY_US 100
31 #define HWSPINLOCK_UNUSED (0) /* tags an hwspinlock as unused */
34 * A radix tree is used to maintain the available hwspinlock instances.
35 * The tree associates hwspinlock pointers with their integer key id,
36 * and provides easy-to-use API which makes the hwspinlock core code simple
39 * Radix trees are quick on lookups, and reasonably efficient in terms of
40 * storage, especially with high density usages such as this framework
41 * requires (a continuous range of integer keys, beginning with zero, is
42 * used as the ID's of the hwspinlock instances).
44 * The radix tree API supports tagging items in the tree, which this
45 * framework uses to mark unused hwspinlock instances (see the
46 * HWSPINLOCK_UNUSED tag above). As a result, the process of querying the
47 * tree, looking for an unused hwspinlock instance, is now reduced to a
48 * single radix tree API call.
50 static RADIX_TREE(hwspinlock_tree, GFP_KERNEL);
53 * Synchronization of access to the tree is achieved using this mutex,
54 * as the radix-tree API requires that users provide all synchronisation.
55 * A mutex is needed because we're using non-atomic radix tree allocations.
57 static DEFINE_MUTEX(hwspinlock_tree_lock);
61 * __hwspin_trylock() - attempt to lock a specific hwspinlock
62 * @hwlock: an hwspinlock which we want to trylock
63 * @mode: controls whether local interrupts are disabled or not
64 * @flags: a pointer where the caller's interrupt state will be saved at (if
67 * This function attempts to lock an hwspinlock, and will immediately
68 * fail if the hwspinlock is already taken.
70 * Caution: If the mode is HWLOCK_RAW, that means user must protect the routine
71 * of getting hardware lock with mutex or spinlock. Since in some scenarios,
72 * user need some time-consuming or sleepable operations under the hardware
73 * lock, they need one sleepable lock (like mutex) to protect the operations.
75 * If the mode is neither HWLOCK_IN_ATOMIC nor HWLOCK_RAW, upon a successful
76 * return from this function, preemption (and possibly interrupts) is disabled,
77 * so the caller must not sleep, and is advised to release the hwspinlock as
78 * soon as possible. This is required in order to minimize remote cores polling
79 * on the hardware interconnect.
81 * The user decides whether local interrupts are disabled or not, and if yes,
82 * whether he wants their previous state to be saved. It is up to the user
83 * to choose the appropriate @mode of operation, exactly the same way users
84 * should decide between spin_trylock, spin_trylock_irq and
85 * spin_trylock_irqsave.
87 * Returns: %0 if we successfully locked the hwspinlock or -EBUSY if
88 * the hwspinlock was already taken.
90 * This function will never sleep.
92 int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
96 if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))
100 * This spin_lock{_irq, _irqsave} serves three purposes:
102 * 1. Disable preemption, in order to minimize the period of time
103 * in which the hwspinlock is taken. This is important in order
104 * to minimize the possible polling on the hardware interconnect
105 * by a remote user of this lock.
106 * 2. Make the hwspinlock SMP-safe (so we can take it from
107 * additional contexts on the local host).
108 * 3. Ensure that in_atomic/might_sleep checks catch potential
109 * problems with hwspinlock usage (e.g. scheduler checks like
110 * 'scheduling while atomic' etc.)
113 case HWLOCK_IRQSTATE:
114 ret = spin_trylock_irqsave(&hwlock->lock, *flags);
117 ret = spin_trylock_irq(&hwlock->lock);
120 case HWLOCK_IN_ATOMIC:
124 ret = spin_trylock(&hwlock->lock);
128 /* is lock already taken by another context on the local cpu ? */
132 /* try to take the hwspinlock device */
133 ret = hwlock->bank->ops->trylock(hwlock);
135 /* if hwlock is already taken, undo spin_trylock_* and exit */
138 case HWLOCK_IRQSTATE:
139 spin_unlock_irqrestore(&hwlock->lock, *flags);
142 spin_unlock_irq(&hwlock->lock);
145 case HWLOCK_IN_ATOMIC:
149 spin_unlock(&hwlock->lock);
157 * We can be sure the other core's memory operations
158 * are observable to us only _after_ we successfully take
159 * the hwspinlock, and we must make sure that subsequent memory
160 * operations (both reads and writes) will not be reordered before
161 * we actually took the hwspinlock.
163 * Note: the implicit memory barrier of the spinlock above is too
164 * early, so we need this additional explicit memory barrier.
170 EXPORT_SYMBOL_GPL(__hwspin_trylock);
173 * __hwspin_lock_timeout() - lock an hwspinlock with timeout limit
174 * @hwlock: the hwspinlock to be locked
175 * @to: timeout value in msecs
176 * @mode: mode which controls whether local interrupts are disabled or not
177 * @flags: a pointer to where the caller's interrupt state will be saved at (if
180 * This function locks the given @hwlock. If the @hwlock
181 * is already taken, the function will busy loop waiting for it to
182 * be released, but give up after @timeout msecs have elapsed.
184 * Caution: If the mode is HWLOCK_RAW, that means user must protect the routine
185 * of getting hardware lock with mutex or spinlock. Since in some scenarios,
186 * user need some time-consuming or sleepable operations under the hardware
187 * lock, they need one sleepable lock (like mutex) to protect the operations.
189 * If the mode is HWLOCK_IN_ATOMIC (called from an atomic context) the timeout
190 * is handled with busy-waiting delays, hence shall not exceed few msecs.
192 * If the mode is neither HWLOCK_IN_ATOMIC nor HWLOCK_RAW, upon a successful
193 * return from this function, preemption (and possibly interrupts) is disabled,
194 * so the caller must not sleep, and is advised to release the hwspinlock as
195 * soon as possible. This is required in order to minimize remote cores polling
196 * on the hardware interconnect.
198 * The user decides whether local interrupts are disabled or not, and if yes,
199 * whether he wants their previous state to be saved. It is up to the user
200 * to choose the appropriate @mode of operation, exactly the same way users
201 * should decide between spin_lock, spin_lock_irq and spin_lock_irqsave.
203 * Returns: %0 when the @hwlock was successfully taken, and an appropriate
204 * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still
205 * busy after @timeout msecs).
207 * The function will never sleep.
209 int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to,
210 int mode, unsigned long *flags)
213 unsigned long expire, atomic_delay = 0;
215 expire = msecs_to_jiffies(to) + jiffies;
218 /* Try to take the hwspinlock */
219 ret = __hwspin_trylock(hwlock, mode, flags);
224 * The lock is already taken, let's check if the user wants
227 if (mode == HWLOCK_IN_ATOMIC) {
228 udelay(HWSPINLOCK_RETRY_DELAY_US);
229 atomic_delay += HWSPINLOCK_RETRY_DELAY_US;
230 if (atomic_delay > to * 1000)
233 if (time_is_before_eq_jiffies(expire))
238 * Allow platform-specific relax handlers to prevent
239 * hogging the interconnect (no sleeping, though)
241 if (hwlock->bank->ops->relax)
242 hwlock->bank->ops->relax(hwlock);
247 EXPORT_SYMBOL_GPL(__hwspin_lock_timeout);
250 * __hwspin_unlock() - unlock a specific hwspinlock
251 * @hwlock: a previously-acquired hwspinlock which we want to unlock
252 * @mode: controls whether local interrupts needs to be restored or not
253 * @flags: previous caller's interrupt state to restore (if requested)
255 * This function will unlock a specific hwspinlock, enable preemption and
256 * (possibly) enable interrupts or restore their previous state.
257 * @hwlock must be already locked before calling this function: it is a bug
258 * to call unlock on a @hwlock that is already unlocked.
260 * The user decides whether local interrupts should be enabled or not, and
261 * if yes, whether he wants their previous state to be restored. It is up
262 * to the user to choose the appropriate @mode of operation, exactly the
263 * same way users decide between spin_unlock, spin_unlock_irq and
264 * spin_unlock_irqrestore.
266 * The function will never sleep.
268 void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
270 if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))
274 * We must make sure that memory operations (both reads and writes),
275 * done before unlocking the hwspinlock, will not be reordered
276 * after the lock is released.
278 * That's the purpose of this explicit memory barrier.
280 * Note: the memory barrier induced by the spin_unlock below is too
281 * late; the other core is going to access memory soon after it will
282 * take the hwspinlock, and by then we want to be sure our memory
283 * operations are already observable.
287 hwlock->bank->ops->unlock(hwlock);
289 /* Undo the spin_trylock{_irq, _irqsave} called while locking */
291 case HWLOCK_IRQSTATE:
292 spin_unlock_irqrestore(&hwlock->lock, *flags);
295 spin_unlock_irq(&hwlock->lock);
298 case HWLOCK_IN_ATOMIC:
302 spin_unlock(&hwlock->lock);
306 EXPORT_SYMBOL_GPL(__hwspin_unlock);
309 * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id
310 * @hwlock_spec: hwlock specifier as found in the device tree
312 * This is a simple translation function, suitable for hwspinlock platform
313 * drivers that only has a lock specifier length of 1.
315 * Returns: a relative index of the lock within a specified bank on success,
316 * or -EINVAL on invalid specifier cell count.
319 of_hwspin_lock_simple_xlate(const struct of_phandle_args *hwlock_spec)
321 if (WARN_ON(hwlock_spec->args_count != 1))
324 return hwlock_spec->args[0];
328 * of_hwspin_lock_get_id() - get lock id for an OF phandle-based specific lock
329 * @np: device node from which to request the specific hwlock
330 * @index: index of the hwlock in the list of values
332 * This function provides a means for DT users of the hwspinlock module to
333 * get the global lock id of a specific hwspinlock using the phandle of the
334 * hwspinlock device, so that it can be requested using the normal
335 * hwspin_lock_request_specific() API.
337 * Returns: the global lock id number on success, -EPROBE_DEFER if the
338 * hwspinlock device is not yet registered, -EINVAL on invalid args
339 * specifier value or an appropriate error as returned from the OF parsing
340 * of the DT client node.
342 int of_hwspin_lock_get_id(struct device_node *np, int index)
344 struct of_phandle_args args;
345 struct hwspinlock *hwlock;
346 struct radix_tree_iter iter;
351 ret = of_parse_phandle_with_args(np, "hwlocks", "#hwlock-cells", index,
356 if (!of_device_is_available(args.np)) {
361 /* Find the hwspinlock device: we need its base_id */
364 radix_tree_for_each_slot(slot, &hwspinlock_tree, &iter, 0) {
365 hwlock = radix_tree_deref_slot(slot);
366 if (unlikely(!hwlock))
368 if (radix_tree_deref_retry(hwlock)) {
369 slot = radix_tree_iter_retry(&iter);
373 if (device_match_of_node(hwlock->bank->dev, args.np)) {
382 id = of_hwspin_lock_simple_xlate(&args);
383 if (id < 0 || id >= hwlock->bank->num_locks) {
387 id += hwlock->bank->base_id;
390 of_node_put(args.np);
391 return ret ? ret : id;
393 EXPORT_SYMBOL_GPL(of_hwspin_lock_get_id);
396 * of_hwspin_lock_get_id_byname() - get lock id for an specified hwlock name
397 * @np: device node from which to request the specific hwlock
400 * This function provides a means for DT users of the hwspinlock module to
401 * get the global lock id of a specific hwspinlock using the specified name of
402 * the hwspinlock device, so that it can be requested using the normal
403 * hwspin_lock_request_specific() API.
405 * Returns: the global lock id number on success, -EPROBE_DEFER if the
406 * hwspinlock device is not yet registered, -EINVAL on invalid args
407 * specifier value or an appropriate error as returned from the OF parsing
408 * of the DT client node.
410 int of_hwspin_lock_get_id_byname(struct device_node *np, const char *name)
417 index = of_property_match_string(np, "hwlock-names", name);
421 return of_hwspin_lock_get_id(np, index);
423 EXPORT_SYMBOL_GPL(of_hwspin_lock_get_id_byname);
425 static int hwspin_lock_register_single(struct hwspinlock *hwlock, int id)
427 struct hwspinlock *tmp;
430 mutex_lock(&hwspinlock_tree_lock);
432 ret = radix_tree_insert(&hwspinlock_tree, id, hwlock);
435 pr_err("hwspinlock id %d already exists!\n", id);
439 /* mark this hwspinlock as available */
440 tmp = radix_tree_tag_set(&hwspinlock_tree, id, HWSPINLOCK_UNUSED);
442 /* self-sanity check which should never fail */
443 WARN_ON(tmp != hwlock);
446 mutex_unlock(&hwspinlock_tree_lock);
450 static struct hwspinlock *hwspin_lock_unregister_single(unsigned int id)
452 struct hwspinlock *hwlock = NULL;
455 mutex_lock(&hwspinlock_tree_lock);
457 /* make sure the hwspinlock is not in use (tag is set) */
458 ret = radix_tree_tag_get(&hwspinlock_tree, id, HWSPINLOCK_UNUSED);
460 pr_err("hwspinlock %d still in use (or not present)\n", id);
464 hwlock = radix_tree_delete(&hwspinlock_tree, id);
466 pr_err("failed to delete hwspinlock %d\n", id);
471 mutex_unlock(&hwspinlock_tree_lock);
476 * hwspin_lock_register() - register a new hw spinlock device
477 * @bank: the hwspinlock device, which usually provides numerous hw locks
478 * @dev: the backing device
479 * @ops: hwspinlock handlers for this device
480 * @base_id: id of the first hardware spinlock in this bank
481 * @num_locks: number of hwspinlocks provided by this device
483 * This function should be called from the underlying platform-specific
484 * implementation, to register a new hwspinlock device instance.
486 * Should be called from a process context (might sleep)
488 * Returns: %0 on success, or an appropriate error code on failure
490 int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
491 const struct hwspinlock_ops *ops, int base_id, int num_locks)
493 struct hwspinlock *hwlock;
496 if (!bank || !ops || !dev || !num_locks || !ops->trylock ||
498 pr_err("invalid parameters\n");
504 bank->base_id = base_id;
505 bank->num_locks = num_locks;
507 for (i = 0; i < num_locks; i++) {
508 hwlock = &bank->lock[i];
510 spin_lock_init(&hwlock->lock);
513 ret = hwspin_lock_register_single(hwlock, base_id + i);
522 hwspin_lock_unregister_single(base_id + i);
525 EXPORT_SYMBOL_GPL(hwspin_lock_register);
528 * hwspin_lock_unregister() - unregister an hw spinlock device
529 * @bank: the hwspinlock device, which usually provides numerous hw locks
531 * This function should be called from the underlying platform-specific
532 * implementation, to unregister an existing (and unused) hwspinlock.
534 * Should be called from a process context (might sleep)
536 * Returns: %0 on success, or an appropriate error code on failure
538 int hwspin_lock_unregister(struct hwspinlock_device *bank)
540 struct hwspinlock *hwlock, *tmp;
543 for (i = 0; i < bank->num_locks; i++) {
544 hwlock = &bank->lock[i];
546 tmp = hwspin_lock_unregister_single(bank->base_id + i);
550 /* self-sanity check that should never fail */
551 WARN_ON(tmp != hwlock);
556 EXPORT_SYMBOL_GPL(hwspin_lock_unregister);
558 static void devm_hwspin_lock_unreg(struct device *dev, void *res)
560 hwspin_lock_unregister(*(struct hwspinlock_device **)res);
563 static int devm_hwspin_lock_device_match(struct device *dev, void *res,
566 struct hwspinlock_device **bank = res;
568 if (WARN_ON(!bank || !*bank))
571 return *bank == data;
575 * devm_hwspin_lock_unregister() - unregister an hw spinlock device for
577 * @dev: the backing device
578 * @bank: the hwspinlock device, which usually provides numerous hw locks
580 * This function should be called from the underlying platform-specific
581 * implementation, to unregister an existing (and unused) hwspinlock.
583 * Should be called from a process context (might sleep)
585 * Returns: %0 on success, or an appropriate error code on failure
587 int devm_hwspin_lock_unregister(struct device *dev,
588 struct hwspinlock_device *bank)
592 ret = devres_release(dev, devm_hwspin_lock_unreg,
593 devm_hwspin_lock_device_match, bank);
598 EXPORT_SYMBOL_GPL(devm_hwspin_lock_unregister);
601 * devm_hwspin_lock_register() - register a new hw spinlock device for
603 * @dev: the backing device
604 * @bank: the hwspinlock device, which usually provides numerous hw locks
605 * @ops: hwspinlock handlers for this device
606 * @base_id: id of the first hardware spinlock in this bank
607 * @num_locks: number of hwspinlocks provided by this device
609 * This function should be called from the underlying platform-specific
610 * implementation, to register a new hwspinlock device instance.
612 * Should be called from a process context (might sleep)
614 * Returns: %0 on success, or an appropriate error code on failure
616 int devm_hwspin_lock_register(struct device *dev,
617 struct hwspinlock_device *bank,
618 const struct hwspinlock_ops *ops,
619 int base_id, int num_locks)
621 struct hwspinlock_device **ptr;
624 ptr = devres_alloc(devm_hwspin_lock_unreg, sizeof(*ptr), GFP_KERNEL);
628 ret = hwspin_lock_register(bank, dev, ops, base_id, num_locks);
631 devres_add(dev, ptr);
638 EXPORT_SYMBOL_GPL(devm_hwspin_lock_register);
641 * __hwspin_lock_request() - tag an hwspinlock as used and power it up
642 * @hwlock: the target hwspinlock
644 * This is an internal function that prepares an hwspinlock instance
645 * before it is given to the user. The function assumes that
646 * hwspinlock_tree_lock is taken.
648 * Returns: %0 or positive to indicate success, and a negative value to
649 * indicate an error (with the appropriate error code)
651 static int __hwspin_lock_request(struct hwspinlock *hwlock)
653 struct device *dev = hwlock->bank->dev;
654 struct hwspinlock *tmp;
657 /* prevent underlying implementation from being removed */
658 if (!try_module_get(dev->driver->owner)) {
659 dev_err(dev, "%s: can't get owner\n", __func__);
663 /* notify PM core that power is now needed */
664 ret = pm_runtime_get_sync(dev);
665 if (ret < 0 && ret != -EACCES) {
666 dev_err(dev, "%s: can't power on device\n", __func__);
667 pm_runtime_put_noidle(dev);
668 module_put(dev->driver->owner);
674 /* mark hwspinlock as used, should not fail */
675 tmp = radix_tree_tag_clear(&hwspinlock_tree, hwlock_to_id(hwlock),
678 /* self-sanity check that should never fail */
679 WARN_ON(tmp != hwlock);
685 * hwspin_lock_get_id() - retrieve id number of a given hwspinlock
686 * @hwlock: a valid hwspinlock instance
688 * Returns: the id number of a given @hwlock, or -EINVAL if @hwlock is invalid.
690 int hwspin_lock_get_id(struct hwspinlock *hwlock)
693 pr_err("invalid hwlock\n");
697 return hwlock_to_id(hwlock);
699 EXPORT_SYMBOL_GPL(hwspin_lock_get_id);
702 * hwspin_lock_request() - request an hwspinlock
704 * This function should be called by users of the hwspinlock device,
705 * in order to dynamically assign them an unused hwspinlock.
706 * Usually the user of this lock will then have to communicate the lock's id
707 * to the remote core before it can be used for synchronization (to get the
708 * id of a given hwlock, use hwspin_lock_get_id()).
710 * Should be called from a process context (might sleep)
712 * Returns: the address of the assigned hwspinlock, or %NULL on error
714 struct hwspinlock *hwspin_lock_request(void)
716 struct hwspinlock *hwlock;
719 mutex_lock(&hwspinlock_tree_lock);
721 /* look for an unused lock */
722 ret = radix_tree_gang_lookup_tag(&hwspinlock_tree, (void **)&hwlock,
723 0, 1, HWSPINLOCK_UNUSED);
725 pr_warn("a free hwspinlock is not available\n");
730 /* sanity check that should never fail */
733 /* mark as used and power up */
734 ret = __hwspin_lock_request(hwlock);
739 mutex_unlock(&hwspinlock_tree_lock);
742 EXPORT_SYMBOL_GPL(hwspin_lock_request);
745 * hwspin_lock_request_specific() - request for a specific hwspinlock
746 * @id: index of the specific hwspinlock that is requested
748 * This function should be called by users of the hwspinlock module,
749 * in order to assign them a specific hwspinlock.
750 * Usually early board code will be calling this function in order to
751 * reserve specific hwspinlock ids for predefined purposes.
753 * Should be called from a process context (might sleep)
755 * Returns: the address of the assigned hwspinlock, or %NULL on error
757 struct hwspinlock *hwspin_lock_request_specific(unsigned int id)
759 struct hwspinlock *hwlock;
762 mutex_lock(&hwspinlock_tree_lock);
764 /* make sure this hwspinlock exists */
765 hwlock = radix_tree_lookup(&hwspinlock_tree, id);
767 pr_warn("hwspinlock %u does not exist\n", id);
771 /* sanity check (this shouldn't happen) */
772 WARN_ON(hwlock_to_id(hwlock) != id);
774 /* make sure this hwspinlock is unused */
775 ret = radix_tree_tag_get(&hwspinlock_tree, id, HWSPINLOCK_UNUSED);
777 pr_warn("hwspinlock %u is already in use\n", id);
782 /* mark as used and power up */
783 ret = __hwspin_lock_request(hwlock);
788 mutex_unlock(&hwspinlock_tree_lock);
791 EXPORT_SYMBOL_GPL(hwspin_lock_request_specific);
794 * hwspin_lock_free() - free a specific hwspinlock
795 * @hwlock: the specific hwspinlock to free
797 * This function mark @hwlock as free again.
798 * Should only be called with an @hwlock that was retrieved from
799 * an earlier call to hwspin_lock_request{_specific}.
801 * Should be called from a process context (might sleep)
803 * Returns: %0 on success, or an appropriate error code on failure
805 int hwspin_lock_free(struct hwspinlock *hwlock)
808 struct hwspinlock *tmp;
812 pr_err("invalid hwlock\n");
816 dev = hwlock->bank->dev;
817 mutex_lock(&hwspinlock_tree_lock);
819 /* make sure the hwspinlock is used */
820 ret = radix_tree_tag_get(&hwspinlock_tree, hwlock_to_id(hwlock),
823 dev_err(dev, "%s: hwlock is already free\n", __func__);
829 /* notify the underlying device that power is not needed */
832 /* mark this hwspinlock as available */
833 tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock_to_id(hwlock),
836 /* sanity check (this shouldn't happen) */
837 WARN_ON(tmp != hwlock);
839 module_put(dev->driver->owner);
842 mutex_unlock(&hwspinlock_tree_lock);
845 EXPORT_SYMBOL_GPL(hwspin_lock_free);
847 static int devm_hwspin_lock_match(struct device *dev, void *res, void *data)
849 struct hwspinlock **hwlock = res;
851 if (WARN_ON(!hwlock || !*hwlock))
854 return *hwlock == data;
857 static void devm_hwspin_lock_release(struct device *dev, void *res)
859 hwspin_lock_free(*(struct hwspinlock **)res);
863 * devm_hwspin_lock_free() - free a specific hwspinlock for a managed device
864 * @dev: the device to free the specific hwspinlock
865 * @hwlock: the specific hwspinlock to free
867 * This function mark @hwlock as free again.
868 * Should only be called with an @hwlock that was retrieved from
869 * an earlier call to hwspin_lock_request{_specific}.
871 * Should be called from a process context (might sleep)
873 * Returns: %0 on success, or an appropriate error code on failure
875 int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock)
879 ret = devres_release(dev, devm_hwspin_lock_release,
880 devm_hwspin_lock_match, hwlock);
885 EXPORT_SYMBOL_GPL(devm_hwspin_lock_free);
888 * devm_hwspin_lock_request() - request an hwspinlock for a managed device
889 * @dev: the device to request an hwspinlock
891 * This function should be called by users of the hwspinlock device,
892 * in order to dynamically assign them an unused hwspinlock.
893 * Usually the user of this lock will then have to communicate the lock's id
894 * to the remote core before it can be used for synchronization (to get the
895 * id of a given hwlock, use hwspin_lock_get_id()).
897 * Should be called from a process context (might sleep)
899 * Returns: the address of the assigned hwspinlock, or %NULL on error
901 struct hwspinlock *devm_hwspin_lock_request(struct device *dev)
903 struct hwspinlock **ptr, *hwlock;
905 ptr = devres_alloc(devm_hwspin_lock_release, sizeof(*ptr), GFP_KERNEL);
909 hwlock = hwspin_lock_request();
912 devres_add(dev, ptr);
919 EXPORT_SYMBOL_GPL(devm_hwspin_lock_request);
922 * devm_hwspin_lock_request_specific() - request for a specific hwspinlock for
924 * @dev: the device to request the specific hwspinlock
925 * @id: index of the specific hwspinlock that is requested
927 * This function should be called by users of the hwspinlock module,
928 * in order to assign them a specific hwspinlock.
929 * Usually early board code will be calling this function in order to
930 * reserve specific hwspinlock ids for predefined purposes.
932 * Should be called from a process context (might sleep)
934 * Returns: the address of the assigned hwspinlock, or %NULL on error
936 struct hwspinlock *devm_hwspin_lock_request_specific(struct device *dev,
939 struct hwspinlock **ptr, *hwlock;
941 ptr = devres_alloc(devm_hwspin_lock_release, sizeof(*ptr), GFP_KERNEL);
945 hwlock = hwspin_lock_request_specific(id);
948 devres_add(dev, ptr);
955 EXPORT_SYMBOL_GPL(devm_hwspin_lock_request_specific);
957 MODULE_DESCRIPTION("Hardware spinlock interface");
958 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");