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  * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id
310  * @hwlock_spec: hwlock specifier as found in the device tree
316  * or -EINVAL on invalid specifier cell count.
321 	if (WARN_ON(hwlock_spec->args_count != 1))  in of_hwspin_lock_simple_xlate()
322 		return -EINVAL;  in of_hwspin_lock_simple_xlate()
324 	return hwlock_spec->args[0];  in of_hwspin_lock_simple_xlate()
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
337  * Returns: the global lock id number on success, -EPROBE_DEFER if the
338  * hwspinlock device is not yet registered, -EINVAL on invalid args
345 	struct hwspinlock *hwlock;  in of_hwspin_lock_get_id()  local
351 	ret = of_parse_phandle_with_args(np, "hwlocks", "#hwlock-cells", index,  in of_hwspin_lock_get_id()
357 		ret = -ENOENT;  in of_hwspin_lock_get_id()
362 	ret = -EPROBE_DEFER;  in of_hwspin_lock_get_id()
365 		hwlock = radix_tree_deref_slot(slot);  in of_hwspin_lock_get_id()
366 		if (unlikely(!hwlock))  in of_hwspin_lock_get_id()
368 		if (radix_tree_deref_retry(hwlock)) {  in of_hwspin_lock_get_id()
373 		if (device_match_of_node(hwlock->bank->dev, args.np)) {  in of_hwspin_lock_get_id()
383 	if (id < 0 || id >= hwlock->bank->num_locks) {  in of_hwspin_lock_get_id()
384 		ret = -EINVAL;  in of_hwspin_lock_get_id()
387 	id += hwlock->bank->base_id;  in 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
398  * @name: hwlock name
405  * Returns: the global lock id number on success, -EPROBE_DEFER if the
406  * hwspinlock device is not yet registered, -EINVAL on invalid args
415 		return -EINVAL;  in of_hwspin_lock_get_id_byname()
417 	index = of_property_match_string(np, "hwlock-names", name);  in of_hwspin_lock_get_id_byname()
425 static int hwspin_lock_register_single(struct hwspinlock *hwlock, int id)  in hwspin_lock_register_single()  argument
432 	ret = radix_tree_insert(&hwspinlock_tree, id, hwlock);  in hwspin_lock_register_single()
434 		if (ret == -EEXIST)  in hwspin_lock_register_single()
442 	/* self-sanity check which should never fail */  in hwspin_lock_register_single()
443 	WARN_ON(tmp != hwlock);  in hwspin_lock_register_single()
452 	struct hwspinlock *hwlock = NULL;  in hwspin_lock_unregister_single()  local
464 	hwlock = radix_tree_delete(&hwspinlock_tree, id);  in hwspin_lock_unregister_single()
465 	if (!hwlock) {  in hwspin_lock_unregister_single()
472 	return hwlock;  in hwspin_lock_unregister_single()
476  * hwspin_lock_register() - register a new hw spinlock device
483  * This function should be called from the underlying platform-specific
493 	struct hwspinlock *hwlock;  in hwspin_lock_register()  local
496 	if (!bank || !ops || !dev || !num_locks || !ops->trylock ||  in hwspin_lock_register()
497 							!ops->unlock) {  in hwspin_lock_register()
499 		return -EINVAL;  in hwspin_lock_register()
502 	bank->dev = dev;  in hwspin_lock_register()
503 	bank->ops = ops;  in hwspin_lock_register()
504 	bank->base_id = base_id;  in hwspin_lock_register()
505 	bank->num_locks = num_locks;  in hwspin_lock_register()
508 		hwlock = &bank->lock[i];  in hwspin_lock_register()
510 		spin_lock_init(&hwlock->lock);  in hwspin_lock_register()
511 		hwlock->bank = bank;  in hwspin_lock_register()
513 		ret = hwspin_lock_register_single(hwlock, base_id + i);  in hwspin_lock_register()
521 	while (--i >= 0)  in hwspin_lock_register()
528  * hwspin_lock_unregister() - unregister an hw spinlock device
531  * This function should be called from the underlying platform-specific
540 	struct hwspinlock *hwlock, *tmp;  in hwspin_lock_unregister()  local
543 	for (i = 0; i < bank->num_locks; i++) {  in hwspin_lock_unregister()
544 		hwlock = &bank->lock[i];  in hwspin_lock_unregister()
546 		tmp = hwspin_lock_unregister_single(bank->base_id + i);  in hwspin_lock_unregister()
548 			return -EBUSY;  in hwspin_lock_unregister()
550 		/* self-sanity check that should never fail */  in hwspin_lock_unregister()
551 		WARN_ON(tmp != hwlock);  in hwspin_lock_unregister()
575  * devm_hwspin_lock_unregister() - unregister an hw spinlock device for
580  * This function should be called from the underlying platform-specific
601  * devm_hwspin_lock_register() - register a new hw spinlock device for
609  * This function should be called from the underlying platform-specific
626 		return -ENOMEM;  in devm_hwspin_lock_register()
641  * __hwspin_lock_request() - tag an hwspinlock as used and power it up
642  * @hwlock: the target hwspinlock
651 static int __hwspin_lock_request(struct hwspinlock *hwlock)  in __hwspin_lock_request()  argument
653 	struct device *dev = hwlock->bank->dev;  in __hwspin_lock_request()
658 	if (!try_module_get(dev->driver->owner)) {  in __hwspin_lock_request()
660 		return -EINVAL;  in __hwspin_lock_request()
665 	if (ret < 0 && ret != -EACCES) {  in __hwspin_lock_request()
668 		module_put(dev->driver->owner);  in __hwspin_lock_request()
675 	tmp = radix_tree_tag_clear(&hwspinlock_tree, hwlock_to_id(hwlock),  in __hwspin_lock_request()
678 	/* self-sanity check that should never fail */  in __hwspin_lock_request()
679 	WARN_ON(tmp != hwlock);  in __hwspin_lock_request()
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)  in hwspin_lock_get_id()  argument
692 	if (!hwlock) {  in hwspin_lock_get_id()
693 		pr_err("invalid hwlock\n");  in hwspin_lock_get_id()
694 		return -EINVAL;  in hwspin_lock_get_id()
697 	return hwlock_to_id(hwlock);  in hwspin_lock_get_id()
702  * hwspin_lock_request() - request an hwspinlock
708  * id of a given hwlock, use hwspin_lock_get_id()).
716 	struct hwspinlock *hwlock;  in hwspin_lock_request()  local
722 	ret = radix_tree_gang_lookup_tag(&hwspinlock_tree, (void **)&hwlock,  in hwspin_lock_request()
726 		hwlock = NULL;  in hwspin_lock_request()
734 	ret = __hwspin_lock_request(hwlock);  in hwspin_lock_request()
736 		hwlock = NULL;  in hwspin_lock_request()
740 	return hwlock;  in hwspin_lock_request()
745  * hwspin_lock_request_specific() - request for a specific hwspinlock
759 	struct hwspinlock *hwlock;  in hwspin_lock_request_specific()  local
765 	hwlock = radix_tree_lookup(&hwspinlock_tree, id);  in hwspin_lock_request_specific()
766 	if (!hwlock) {  in hwspin_lock_request_specific()
772 	WARN_ON(hwlock_to_id(hwlock) != id);  in hwspin_lock_request_specific()
778 		hwlock = NULL;  in hwspin_lock_request_specific()
783 	ret = __hwspin_lock_request(hwlock);  in hwspin_lock_request_specific()
785 		hwlock = NULL;  in hwspin_lock_request_specific()
789 	return hwlock;  in 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
805 int hwspin_lock_free(struct hwspinlock *hwlock)  in hwspin_lock_free()  argument
811 	if (!hwlock) {  in hwspin_lock_free()
812 		pr_err("invalid hwlock\n");  in hwspin_lock_free()
813 		return -EINVAL;  in hwspin_lock_free()
816 	dev = hwlock->bank->dev;  in hwspin_lock_free()
820 	ret = radix_tree_tag_get(&hwspinlock_tree, hwlock_to_id(hwlock),  in hwspin_lock_free()
823 		dev_err(dev, "%s: hwlock is already free\n", __func__);  in hwspin_lock_free()
825 		ret = -EINVAL;  in hwspin_lock_free()
833 	tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock_to_id(hwlock),  in hwspin_lock_free()
837 	WARN_ON(tmp != hwlock);  in hwspin_lock_free()
839 	module_put(dev->driver->owner);  in hwspin_lock_free()
849 	struct hwspinlock **hwlock = res;  in devm_hwspin_lock_match()  local
851 	if (WARN_ON(!hwlock || !*hwlock))  in devm_hwspin_lock_match()
854 	return *hwlock == data;  in devm_hwspin_lock_match()
863  * devm_hwspin_lock_free() - free a specific hwspinlock for a managed device
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
875 int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock)  in devm_hwspin_lock_free()  argument
880 			     devm_hwspin_lock_match, hwlock);  in devm_hwspin_lock_free()
888  * devm_hwspin_lock_request() - request an hwspinlock for a managed device
895  * id of a given hwlock, use hwspin_lock_get_id()).
903 	struct hwspinlock **ptr, *hwlock;  in devm_hwspin_lock_request()  local
909 	hwlock = hwspin_lock_request();  in devm_hwspin_lock_request()
910 	if (hwlock) {  in devm_hwspin_lock_request()
911 		*ptr = hwlock;  in devm_hwspin_lock_request()
917 	return hwlock;  in devm_hwspin_lock_request()
922  * devm_hwspin_lock_request_specific() - request for a specific hwspinlock for
939 	struct hwspinlock **ptr, *hwlock;  in devm_hwspin_lock_request_specific()  local
945 	hwlock = hwspin_lock_request_specific(id);  in devm_hwspin_lock_request_specific()
946 	if (hwlock) {  in devm_hwspin_lock_request_specific()
947 		*ptr = hwlock;  in devm_hwspin_lock_request_specific()
953 	return hwlock;  in devm_hwspin_lock_request_specific()
958 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");