1 // SPDX-License-Identifier: GPL-2.0
5  * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
7  * Contact: Ohad Ben-Cohen <ohad@wizery.com>
19 #include <linux/radix-tree.h>
36  * and provides easy-to-use API which makes the hwspinlock core code simple
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.
61  * __hwspin_trylock() - attempt to lock a specific hwspinlock
62  * @hwlock: an hwspinlock which we want to trylock
72  * user need some time-consuming or sleepable operations under the hardware
87  * Returns: %0 if we successfully locked the hwspinlock or -EBUSY if
92 int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)  in __hwspin_trylock()  argument
96 	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))  in __hwspin_trylock()
97 		return -EINVAL;  in __hwspin_trylock()
106 	 * 2. Make the hwspinlock SMP-safe (so we can take it from  in __hwspin_trylock()
114 		ret = spin_trylock_irqsave(&hwlock->lock, *flags);  in __hwspin_trylock()
117 		ret = spin_trylock_irq(&hwlock->lock);  in __hwspin_trylock()
124 		ret = spin_trylock(&hwlock->lock);  in __hwspin_trylock()
130 		return -EBUSY;  in __hwspin_trylock()
133 	ret = hwlock->bank->ops->trylock(hwlock);  in __hwspin_trylock()
135 	/* if hwlock is already taken, undo spin_trylock_* and exit */  in __hwspin_trylock()
139 			spin_unlock_irqrestore(&hwlock->lock, *flags);  in __hwspin_trylock()
142 			spin_unlock_irq(&hwlock->lock);  in __hwspin_trylock()
149 			spin_unlock(&hwlock->lock);  in __hwspin_trylock()
153 		return -EBUSY;  in __hwspin_trylock()
173  * __hwspin_lock_timeout() - lock an hwspinlock with timeout limit
174  * @hwlock: the hwspinlock to be locked
180  * This function locks the given @hwlock. If the @hwlock
186  * user need some time-consuming or sleepable operations under the hardware
190  * is handled with busy-waiting delays, hence shall not exceed few msecs.
203  * Returns: %0 when the @hwlock was successfully taken, and an appropriate
204  * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still
209 int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to,  in __hwspin_lock_timeout()  argument
219 		ret = __hwspin_trylock(hwlock, mode, flags);  in __hwspin_lock_timeout()
220 		if (ret != -EBUSY)  in __hwspin_lock_timeout()
231 				return -ETIMEDOUT;  in __hwspin_lock_timeout()
234 				return -ETIMEDOUT;  in __hwspin_lock_timeout()
238 		 * Allow platform-specific relax handlers to prevent  in __hwspin_lock_timeout()
241 		if (hwlock->bank->ops->relax)  in __hwspin_lock_timeout()
242 			hwlock->bank->ops->relax(hwlock);  in __hwspin_lock_timeout()
250  * __hwspin_unlock() - unlock a specific hwspinlock
251  * @hwlock: a previously-acquired hwspinlock which we want to unlock
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.
268 void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)  in __hwspin_unlock()  argument
270 	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))  in __hwspin_unlock()
287 	hwlock->bank->ops->unlock(hwlock);  in __hwspin_unlock()
292 		spin_unlock_irqrestore(&hwlock->lock, *flags);  in __hwspin_unlock()
295 		spin_unlock_irq(&hwlock->lock);  in __hwspin_unlock()
302 		spin_unlock(&hwlock->lock);  in __hwspin_unlock()
309  * hwspin_lock_bust() - bust a specific hwspinlock
310  * @hwlock: a previously-acquired hwspinlock which we want to bust
318  * Returns: 0 on success, or -EINVAL if the hwspinlock does not exist, or
319  * the bust operation fails, and -EOPNOTSUPP if the bust operation is not
322 int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id)  in hwspin_lock_bust()  argument
324 	if (WARN_ON(!hwlock))  in hwspin_lock_bust()
325 		return -EINVAL;  in hwspin_lock_bust()
327 	if (!hwlock->bank->ops->bust) {  in hwspin_lock_bust()
329 		return -EOPNOTSUPP;  in hwspin_lock_bust()
332 	return hwlock->bank->ops->bust(hwlock, id);  in hwspin_lock_bust()
337  * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id
338  * @hwlock_spec: hwlock specifier as found in the device tree
344  * or -EINVAL on invalid specifier cell count.
349 	if (WARN_ON(hwlock_spec->args_count != 1))  in of_hwspin_lock_simple_xlate()
350 		return -EINVAL;  in of_hwspin_lock_simple_xlate()
352 	return hwlock_spec->args[0];  in of_hwspin_lock_simple_xlate()
356  * of_hwspin_lock_get_id() - get lock id for an OF phandle-based specific lock
357  * @np: device node from which to request the specific hwlock
358  * @index: index of the hwlock in the list of values
365  * Returns: the global lock id number on success, -EPROBE_DEFER if the
366  * hwspinlock device is not yet registered, -EINVAL on invalid args
373 	struct hwspinlock *hwlock;  in of_hwspin_lock_get_id()  local
379 	ret = of_parse_phandle_with_args(np, "hwlocks", "#hwlock-cells", index,  in of_hwspin_lock_get_id()
385 		ret = -ENOENT;  in of_hwspin_lock_get_id()
390 	ret = -EPROBE_DEFER;  in of_hwspin_lock_get_id()
393 		hwlock = radix_tree_deref_slot(slot);  in of_hwspin_lock_get_id()
394 		if (unlikely(!hwlock))  in of_hwspin_lock_get_id()
396 		if (radix_tree_deref_retry(hwlock)) {  in of_hwspin_lock_get_id()
401 		if (device_match_of_node(hwlock->bank->dev, args.np)) {  in of_hwspin_lock_get_id()
411 	if (id < 0 || id >= hwlock->bank->num_locks) {  in of_hwspin_lock_get_id()
412 		ret = -EINVAL;  in of_hwspin_lock_get_id()
415 	id += hwlock->bank->base_id;  in of_hwspin_lock_get_id()
424  * of_hwspin_lock_get_id_byname() - get lock id for an specified hwlock name
425  * @np: device node from which to request the specific hwlock
426  * @name: hwlock name
433  * Returns: the global lock id number on success, -EPROBE_DEFER if the
434  * hwspinlock device is not yet registered, -EINVAL on invalid args
443 		return -EINVAL;  in of_hwspin_lock_get_id_byname()
445 	index = of_property_match_string(np, "hwlock-names", name);  in of_hwspin_lock_get_id_byname()
453 static int hwspin_lock_register_single(struct hwspinlock *hwlock, int id)  in hwspin_lock_register_single()  argument
460 	ret = radix_tree_insert(&hwspinlock_tree, id, hwlock);  in hwspin_lock_register_single()
462 		if (ret == -EEXIST)  in hwspin_lock_register_single()
470 	/* self-sanity check which should never fail */  in hwspin_lock_register_single()
471 	WARN_ON(tmp != hwlock);  in hwspin_lock_register_single()
480 	struct hwspinlock *hwlock = NULL;  in hwspin_lock_unregister_single()  local
492 	hwlock = radix_tree_delete(&hwspinlock_tree, id);  in hwspin_lock_unregister_single()
493 	if (!hwlock) {  in hwspin_lock_unregister_single()
500 	return hwlock;  in hwspin_lock_unregister_single()
504  * hwspin_lock_register() - register a new hw spinlock device
511  * This function should be called from the underlying platform-specific
521 	struct hwspinlock *hwlock;  in hwspin_lock_register()  local
524 	if (!bank || !ops || !dev || !num_locks || !ops->trylock ||  in hwspin_lock_register()
525 							!ops->unlock) {  in hwspin_lock_register()
527 		return -EINVAL;  in hwspin_lock_register()
530 	bank->dev = dev;  in hwspin_lock_register()
531 	bank->ops = ops;  in hwspin_lock_register()
532 	bank->base_id = base_id;  in hwspin_lock_register()
533 	bank->num_locks = num_locks;  in hwspin_lock_register()
536 		hwlock = &bank->lock[i];  in hwspin_lock_register()
538 		spin_lock_init(&hwlock->lock);  in hwspin_lock_register()
539 		hwlock->bank = bank;  in hwspin_lock_register()
541 		ret = hwspin_lock_register_single(hwlock, base_id + i);  in hwspin_lock_register()
549 	while (--i >= 0)  in hwspin_lock_register()
556  * hwspin_lock_unregister() - unregister an hw spinlock device
559  * This function should be called from the underlying platform-specific
568 	struct hwspinlock *hwlock, *tmp;  in hwspin_lock_unregister()  local
571 	for (i = 0; i < bank->num_locks; i++) {  in hwspin_lock_unregister()
572 		hwlock = &bank->lock[i];  in hwspin_lock_unregister()
574 		tmp = hwspin_lock_unregister_single(bank->base_id + i);  in hwspin_lock_unregister()
576 			return -EBUSY;  in hwspin_lock_unregister()
578 		/* self-sanity check that should never fail */  in hwspin_lock_unregister()
579 		WARN_ON(tmp != hwlock);  in hwspin_lock_unregister()
603  * devm_hwspin_lock_unregister() - unregister an hw spinlock device for
608  * This function should be called from the underlying platform-specific
629  * devm_hwspin_lock_register() - register a new hw spinlock device for
637  * This function should be called from the underlying platform-specific
654 		return -ENOMEM;  in devm_hwspin_lock_register()
669  * __hwspin_lock_request() - tag an hwspinlock as used and power it up
670  * @hwlock: the target hwspinlock
679 static int __hwspin_lock_request(struct hwspinlock *hwlock)  in __hwspin_lock_request()  argument
681 	struct device *dev = hwlock->bank->dev;  in __hwspin_lock_request()
686 	if (!try_module_get(dev->driver->owner)) {  in __hwspin_lock_request()
688 		return -EINVAL;  in __hwspin_lock_request()
693 	if (ret < 0 && ret != -EACCES) {  in __hwspin_lock_request()
696 		module_put(dev->driver->owner);  in __hwspin_lock_request()
703 	tmp = radix_tree_tag_clear(&hwspinlock_tree, hwlock_to_id(hwlock),  in __hwspin_lock_request()
706 	/* self-sanity check that should never fail */  in __hwspin_lock_request()
707 	WARN_ON(tmp != hwlock);  in __hwspin_lock_request()
713  * hwspin_lock_get_id() - retrieve id number of a given hwspinlock
714  * @hwlock: a valid hwspinlock instance
716  * Returns: the id number of a given @hwlock, or -EINVAL if @hwlock is invalid.
718 int hwspin_lock_get_id(struct hwspinlock *hwlock)  in hwspin_lock_get_id()  argument
720 	if (!hwlock) {  in hwspin_lock_get_id()
721 		pr_err("invalid hwlock\n");  in hwspin_lock_get_id()
722 		return -EINVAL;  in hwspin_lock_get_id()
725 	return hwlock_to_id(hwlock);  in hwspin_lock_get_id()
730  * hwspin_lock_request() - request an hwspinlock
736  * id of a given hwlock, use hwspin_lock_get_id()).
744 	struct hwspinlock *hwlock;  in hwspin_lock_request()  local
750 	ret = radix_tree_gang_lookup_tag(&hwspinlock_tree, (void **)&hwlock,  in hwspin_lock_request()
754 		hwlock = NULL;  in hwspin_lock_request()
762 	ret = __hwspin_lock_request(hwlock);  in hwspin_lock_request()
764 		hwlock = NULL;  in hwspin_lock_request()
768 	return hwlock;  in hwspin_lock_request()
773  * hwspin_lock_request_specific() - request for a specific hwspinlock
787 	struct hwspinlock *hwlock;  in hwspin_lock_request_specific()  local
793 	hwlock = radix_tree_lookup(&hwspinlock_tree, id);  in hwspin_lock_request_specific()
794 	if (!hwlock) {  in hwspin_lock_request_specific()
800 	WARN_ON(hwlock_to_id(hwlock) != id);  in hwspin_lock_request_specific()
806 		hwlock = NULL;  in hwspin_lock_request_specific()
811 	ret = __hwspin_lock_request(hwlock);  in hwspin_lock_request_specific()
813 		hwlock = NULL;  in hwspin_lock_request_specific()
817 	return hwlock;  in hwspin_lock_request_specific()
822  * hwspin_lock_free() - free a specific hwspinlock
823  * @hwlock: the specific hwspinlock to free
825  * This function mark @hwlock as free again.
826  * Should only be called with an @hwlock that was retrieved from
833 int hwspin_lock_free(struct hwspinlock *hwlock)  in hwspin_lock_free()  argument
839 	if (!hwlock) {  in hwspin_lock_free()
840 		pr_err("invalid hwlock\n");  in hwspin_lock_free()
841 		return -EINVAL;  in hwspin_lock_free()
844 	dev = hwlock->bank->dev;  in hwspin_lock_free()
848 	ret = radix_tree_tag_get(&hwspinlock_tree, hwlock_to_id(hwlock),  in hwspin_lock_free()
851 		dev_err(dev, "%s: hwlock is already free\n", __func__);  in hwspin_lock_free()
853 		ret = -EINVAL;  in hwspin_lock_free()
861 	tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock_to_id(hwlock),  in hwspin_lock_free()
865 	WARN_ON(tmp != hwlock);  in hwspin_lock_free()
867 	module_put(dev->driver->owner);  in hwspin_lock_free()
877 	struct hwspinlock **hwlock = res;  in devm_hwspin_lock_match()  local
879 	if (WARN_ON(!hwlock || !*hwlock))  in devm_hwspin_lock_match()
882 	return *hwlock == data;  in devm_hwspin_lock_match()
891  * devm_hwspin_lock_free() - free a specific hwspinlock for a managed device
893  * @hwlock: the specific hwspinlock to free
895  * This function mark @hwlock as free again.
896  * Should only be called with an @hwlock that was retrieved from
903 int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock)  in devm_hwspin_lock_free()  argument
908 			     devm_hwspin_lock_match, hwlock);  in devm_hwspin_lock_free()
916  * devm_hwspin_lock_request() - request an hwspinlock for a managed device
923  * id of a given hwlock, use hwspin_lock_get_id()).
931 	struct hwspinlock **ptr, *hwlock;  in devm_hwspin_lock_request()  local
937 	hwlock = hwspin_lock_request();  in devm_hwspin_lock_request()
938 	if (hwlock) {  in devm_hwspin_lock_request()
939 		*ptr = hwlock;  in devm_hwspin_lock_request()
945 	return hwlock;  in devm_hwspin_lock_request()
950  * devm_hwspin_lock_request_specific() - request for a specific hwspinlock for
967 	struct hwspinlock **ptr, *hwlock;  in devm_hwspin_lock_request_specific()  local
973 	hwlock = hwspin_lock_request_specific(id);  in devm_hwspin_lock_request_specific()
974 	if (hwlock) {  in devm_hwspin_lock_request_specific()
975 		*ptr = hwlock;  in devm_hwspin_lock_request_specific()
981 	return hwlock;  in devm_hwspin_lock_request_specific()
986 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");