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
91 int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)  in __hwspin_trylock()  argument
95 	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))  in __hwspin_trylock()
96 		return -EINVAL;  in __hwspin_trylock()
105 	 * 2. Make the hwspinlock SMP-safe (so we can take it from  in __hwspin_trylock()
113 		ret = spin_trylock_irqsave(&hwlock->lock, *flags);  in __hwspin_trylock()
116 		ret = spin_trylock_irq(&hwlock->lock);  in __hwspin_trylock()
123 		ret = spin_trylock(&hwlock->lock);  in __hwspin_trylock()
129 		return -EBUSY;  in __hwspin_trylock()
132 	ret = hwlock->bank->ops->trylock(hwlock);  in __hwspin_trylock()
134 	/* if hwlock is already taken, undo spin_trylock_* and exit */  in __hwspin_trylock()
138 			spin_unlock_irqrestore(&hwlock->lock, *flags);  in __hwspin_trylock()
141 			spin_unlock_irq(&hwlock->lock);  in __hwspin_trylock()
148 			spin_unlock(&hwlock->lock);  in __hwspin_trylock()
152 		return -EBUSY;  in __hwspin_trylock()
172  * __hwspin_lock_timeout() - lock an hwspinlock with timeout limit
173  * @hwlock: the hwspinlock to be locked
179  * This function locks the given @hwlock. If the @hwlock
185  * user need some time-consuming or sleepable operations under the hardware
189  * is handled with busy-waiting delays, hence shall not exceed few msecs.
202  * Returns 0 when the @hwlock was successfully taken, and an appropriate
203  * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still
206 int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to,  in __hwspin_lock_timeout()  argument
216 		ret = __hwspin_trylock(hwlock, mode, flags);  in __hwspin_lock_timeout()
217 		if (ret != -EBUSY)  in __hwspin_lock_timeout()
228 				return -ETIMEDOUT;  in __hwspin_lock_timeout()
231 				return -ETIMEDOUT;  in __hwspin_lock_timeout()
235 		 * Allow platform-specific relax handlers to prevent  in __hwspin_lock_timeout()
238 		if (hwlock->bank->ops->relax)  in __hwspin_lock_timeout()
239 			hwlock->bank->ops->relax(hwlock);  in __hwspin_lock_timeout()
247  * __hwspin_unlock() - unlock a specific hwspinlock
248  * @hwlock: a previously-acquired hwspinlock which we want to unlock
254  * @hwlock must be already locked before calling this function: it is a bug
255  * to call unlock on a @hwlock that is already unlocked.
265 void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)  in __hwspin_unlock()  argument
267 	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))  in __hwspin_unlock()
284 	hwlock->bank->ops->unlock(hwlock);  in __hwspin_unlock()
289 		spin_unlock_irqrestore(&hwlock->lock, *flags);  in __hwspin_unlock()
292 		spin_unlock_irq(&hwlock->lock);  in __hwspin_unlock()
299 		spin_unlock(&hwlock->lock);  in __hwspin_unlock()
306  * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id
308  * @hwlock_spec: hwlock specifier as found in the device tree
314  * or -EINVAL on invalid specifier cell count.
319 	if (WARN_ON(hwlock_spec->args_count != 1))  in of_hwspin_lock_simple_xlate()
320 		return -EINVAL;  in of_hwspin_lock_simple_xlate()
322 	return hwlock_spec->args[0];  in of_hwspin_lock_simple_xlate()
326  * of_hwspin_lock_get_id() - get lock id for an OF phandle-based specific lock
327  * @np: device node from which to request the specific hwlock
328  * @index: index of the hwlock in the list of values
335  * Returns the global lock id number on success, -EPROBE_DEFER if the hwspinlock
336  * device is not yet registered, -EINVAL on invalid args specifier value or an
342 	struct hwspinlock *hwlock;  in of_hwspin_lock_get_id()  local
348 	ret = of_parse_phandle_with_args(np, "hwlocks", "#hwlock-cells", index,  in of_hwspin_lock_get_id()
354 		ret = -ENOENT;  in of_hwspin_lock_get_id()
359 	ret = -EPROBE_DEFER;  in of_hwspin_lock_get_id()
362 		hwlock = radix_tree_deref_slot(slot);  in of_hwspin_lock_get_id()
363 		if (unlikely(!hwlock))  in of_hwspin_lock_get_id()
365 		if (radix_tree_deref_retry(hwlock)) {  in of_hwspin_lock_get_id()
370 		if (hwlock->bank->dev->of_node == args.np) {  in of_hwspin_lock_get_id()
380 	if (id < 0 || id >= hwlock->bank->num_locks) {  in of_hwspin_lock_get_id()
381 		ret = -EINVAL;  in of_hwspin_lock_get_id()
384 	id += hwlock->bank->base_id;  in of_hwspin_lock_get_id()
393  * of_hwspin_lock_get_id_byname() - get lock id for an specified hwlock name
394  * @np: device node from which to request the specific hwlock
395  * @name: hwlock name
402  * Returns the global lock id number on success, -EPROBE_DEFER if the hwspinlock
403  * device is not yet registered, -EINVAL on invalid args specifier value or an
411 		return -EINVAL;  in of_hwspin_lock_get_id_byname()
413 	index = of_property_match_string(np, "hwlock-names", name);  in of_hwspin_lock_get_id_byname()
421 static int hwspin_lock_register_single(struct hwspinlock *hwlock, int id)  in hwspin_lock_register_single()  argument
428 	ret = radix_tree_insert(&hwspinlock_tree, id, hwlock);  in hwspin_lock_register_single()
430 		if (ret == -EEXIST)  in hwspin_lock_register_single()
438 	/* self-sanity check which should never fail */  in hwspin_lock_register_single()
439 	WARN_ON(tmp != hwlock);  in hwspin_lock_register_single()
448 	struct hwspinlock *hwlock = NULL;  in hwspin_lock_unregister_single()  local
460 	hwlock = radix_tree_delete(&hwspinlock_tree, id);  in hwspin_lock_unregister_single()
461 	if (!hwlock) {  in hwspin_lock_unregister_single()
468 	return hwlock;  in hwspin_lock_unregister_single()
472  * hwspin_lock_register() - register a new hw spinlock device
479  * This function should be called from the underlying platform-specific
489 	struct hwspinlock *hwlock;  in hwspin_lock_register()  local
492 	if (!bank || !ops || !dev || !num_locks || !ops->trylock ||  in hwspin_lock_register()
493 							!ops->unlock) {  in hwspin_lock_register()
495 		return -EINVAL;  in hwspin_lock_register()
498 	bank->dev = dev;  in hwspin_lock_register()
499 	bank->ops = ops;  in hwspin_lock_register()
500 	bank->base_id = base_id;  in hwspin_lock_register()
501 	bank->num_locks = num_locks;  in hwspin_lock_register()
504 		hwlock = &bank->lock[i];  in hwspin_lock_register()
506 		spin_lock_init(&hwlock->lock);  in hwspin_lock_register()
507 		hwlock->bank = bank;  in hwspin_lock_register()
509 		ret = hwspin_lock_register_single(hwlock, base_id + i);  in hwspin_lock_register()
517 	while (--i >= 0)  in hwspin_lock_register()
524  * hwspin_lock_unregister() - unregister an hw spinlock device
527  * This function should be called from the underlying platform-specific
536 	struct hwspinlock *hwlock, *tmp;  in hwspin_lock_unregister()  local
539 	for (i = 0; i < bank->num_locks; i++) {  in hwspin_lock_unregister()
540 		hwlock = &bank->lock[i];  in hwspin_lock_unregister()
542 		tmp = hwspin_lock_unregister_single(bank->base_id + i);  in hwspin_lock_unregister()
544 			return -EBUSY;  in hwspin_lock_unregister()
546 		/* self-sanity check that should never fail */  in hwspin_lock_unregister()
547 		WARN_ON(tmp != hwlock);  in hwspin_lock_unregister()
571  * devm_hwspin_lock_unregister() - unregister an hw spinlock device for
576  * This function should be called from the underlying platform-specific
597  * devm_hwspin_lock_register() - register a new hw spinlock device for
605  * This function should be called from the underlying platform-specific
622 		return -ENOMEM;  in devm_hwspin_lock_register()
637  * __hwspin_lock_request() - tag an hwspinlock as used and power it up
646 static int __hwspin_lock_request(struct hwspinlock *hwlock)  in __hwspin_lock_request()  argument
648 	struct device *dev = hwlock->bank->dev;  in __hwspin_lock_request()
653 	if (!try_module_get(dev->driver->owner)) {  in __hwspin_lock_request()
655 		return -EINVAL;  in __hwspin_lock_request()
660 	if (ret < 0 && ret != -EACCES) {  in __hwspin_lock_request()
663 		module_put(dev->driver->owner);  in __hwspin_lock_request()
670 	tmp = radix_tree_tag_clear(&hwspinlock_tree, hwlock_to_id(hwlock),  in __hwspin_lock_request()
673 	/* self-sanity check that should never fail */  in __hwspin_lock_request()
674 	WARN_ON(tmp != hwlock);  in __hwspin_lock_request()
680  * hwspin_lock_get_id() - retrieve id number of a given hwspinlock
681  * @hwlock: a valid hwspinlock instance
683  * Returns the id number of a given @hwlock, or -EINVAL if @hwlock is invalid.
685 int hwspin_lock_get_id(struct hwspinlock *hwlock)  in hwspin_lock_get_id()  argument
687 	if (!hwlock) {  in hwspin_lock_get_id()
688 		pr_err("invalid hwlock\n");  in hwspin_lock_get_id()
689 		return -EINVAL;  in hwspin_lock_get_id()
692 	return hwlock_to_id(hwlock);  in hwspin_lock_get_id()
697  * hwspin_lock_request() - request an hwspinlock
703  * id of a given hwlock, use hwspin_lock_get_id()).
711 	struct hwspinlock *hwlock;  in hwspin_lock_request()  local
717 	ret = radix_tree_gang_lookup_tag(&hwspinlock_tree, (void **)&hwlock,  in hwspin_lock_request()
721 		hwlock = NULL;  in hwspin_lock_request()
729 	ret = __hwspin_lock_request(hwlock);  in hwspin_lock_request()
731 		hwlock = NULL;  in hwspin_lock_request()
735 	return hwlock;  in hwspin_lock_request()
740  * hwspin_lock_request_specific() - request for a specific hwspinlock
754 	struct hwspinlock *hwlock;  in hwspin_lock_request_specific()  local
760 	hwlock = radix_tree_lookup(&hwspinlock_tree, id);  in hwspin_lock_request_specific()
761 	if (!hwlock) {  in hwspin_lock_request_specific()
767 	WARN_ON(hwlock_to_id(hwlock) != id);  in hwspin_lock_request_specific()
773 		hwlock = NULL;  in hwspin_lock_request_specific()
778 	ret = __hwspin_lock_request(hwlock);  in hwspin_lock_request_specific()
780 		hwlock = NULL;  in hwspin_lock_request_specific()
784 	return hwlock;  in hwspin_lock_request_specific()
789  * hwspin_lock_free() - free a specific hwspinlock
790  * @hwlock: the specific hwspinlock to free
792  * This function mark @hwlock as free again.
793  * Should only be called with an @hwlock that was retrieved from
800 int hwspin_lock_free(struct hwspinlock *hwlock)  in hwspin_lock_free()  argument
806 	if (!hwlock) {  in hwspin_lock_free()
807 		pr_err("invalid hwlock\n");  in hwspin_lock_free()
808 		return -EINVAL;  in hwspin_lock_free()
811 	dev = hwlock->bank->dev;  in hwspin_lock_free()
815 	ret = radix_tree_tag_get(&hwspinlock_tree, hwlock_to_id(hwlock),  in hwspin_lock_free()
818 		dev_err(dev, "%s: hwlock is already free\n", __func__);  in hwspin_lock_free()
820 		ret = -EINVAL;  in hwspin_lock_free()
828 	tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock_to_id(hwlock),  in hwspin_lock_free()
832 	WARN_ON(tmp != hwlock);  in hwspin_lock_free()
834 	module_put(dev->driver->owner);  in hwspin_lock_free()
844 	struct hwspinlock **hwlock = res;  in devm_hwspin_lock_match()  local
846 	if (WARN_ON(!hwlock || !*hwlock))  in devm_hwspin_lock_match()
849 	return *hwlock == data;  in devm_hwspin_lock_match()
858  * devm_hwspin_lock_free() - free a specific hwspinlock for a managed device
860  * @hwlock: the specific hwspinlock to free
862  * This function mark @hwlock as free again.
863  * Should only be called with an @hwlock that was retrieved from
870 int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock)  in devm_hwspin_lock_free()  argument
875 			     devm_hwspin_lock_match, hwlock);  in devm_hwspin_lock_free()
883  * devm_hwspin_lock_request() - request an hwspinlock for a managed device
890  * id of a given hwlock, use hwspin_lock_get_id()).
898 	struct hwspinlock **ptr, *hwlock;  in devm_hwspin_lock_request()  local
904 	hwlock = hwspin_lock_request();  in devm_hwspin_lock_request()
905 	if (hwlock) {  in devm_hwspin_lock_request()
906 		*ptr = hwlock;  in devm_hwspin_lock_request()
912 	return hwlock;  in devm_hwspin_lock_request()
917  * devm_hwspin_lock_request_specific() - request for a specific hwspinlock for
934 	struct hwspinlock **ptr, *hwlock;  in devm_hwspin_lock_request_specific()  local
940 	hwlock = hwspin_lock_request_specific(id);  in devm_hwspin_lock_request_specific()
941 	if (hwlock) {  in devm_hwspin_lock_request_specific()
942 		*ptr = hwlock;  in devm_hwspin_lock_request_specific()
948 	return hwlock;  in devm_hwspin_lock_request_specific()
954 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");