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
72  * user need some time-consuming or sleepable operations under the hardware
87  * Returns: %0 if we successfully locked the hwspinlock or -EBUSY if
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()
132 	/* try to take the hwspinlock device */  in __hwspin_trylock()
133 	ret = hwlock->bank->ops->trylock(hwlock);  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
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.
204  * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still
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
255  * This function will unlock a specific hwspinlock, enable preemption and
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
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
361  * get the global lock id of a specific hwspinlock using the phandle of the
362  * hwspinlock device, so that it can be requested using the normal
365  * Returns: the global lock id number on success, -EPROBE_DEFER if the
366  * hwspinlock device is not yet registered, -EINVAL on invalid args
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()
389 	/* Find the hwspinlock device: we need its base_id */  in of_hwspin_lock_get_id()
390 	ret = -EPROBE_DEFER;  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
429  * get the global lock id of a specific hwspinlock using the specified name of
430  * the hwspinlock device, so that it can be requested using the normal
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()
462 		if (ret == -EEXIST)  in hwspin_lock_register_single()
470 	/* self-sanity check which should never fail */  in hwspin_lock_register_single()
504  * hwspin_lock_register() - register a new hw spinlock device
505  * @bank: the hwspinlock device, which usually provides numerous hw locks
506  * @dev: the backing device
507  * @ops: hwspinlock handlers for this device
509  * @num_locks: number of hwspinlocks provided by this device
511  * This function should be called from the underlying platform-specific
512  * implementation, to register a new hwspinlock device instance.
518 int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,  in hwspin_lock_register()
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()
549 	while (--i >= 0)  in hwspin_lock_register()
556  * hwspin_lock_unregister() - unregister an hw spinlock device
557  * @bank: the hwspinlock device, which usually provides numerous hw locks
559  * This function should be called from the underlying platform-specific
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()
586 static void devm_hwspin_lock_unreg(struct device *dev, void *res)  in devm_hwspin_lock_unreg()
591 static int devm_hwspin_lock_device_match(struct device *dev, void *res,  in devm_hwspin_lock_device_match()
603  * devm_hwspin_lock_unregister() - unregister an hw spinlock device for
604  *				   a managed device
605  * @dev: the backing device
606  * @bank: the hwspinlock device, which usually provides numerous hw locks
608  * This function should be called from the underlying platform-specific
615 int devm_hwspin_lock_unregister(struct device *dev,  in devm_hwspin_lock_unregister()
629  * devm_hwspin_lock_register() - register a new hw spinlock device for
630  *				 a managed device
631  * @dev: the backing device
632  * @bank: the hwspinlock device, which usually provides numerous hw locks
633  * @ops: hwspinlock handlers for this device
635  * @num_locks: number of hwspinlocks provided by this device
637  * This function should be called from the underlying platform-specific
638  * implementation, to register a new hwspinlock device instance.
644 int devm_hwspin_lock_register(struct device *dev,  in devm_hwspin_lock_register()
654 		return -ENOMEM;  in devm_hwspin_lock_register()
669  * __hwspin_lock_request() - tag an hwspinlock as used and power it up
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()
694 		dev_err(dev, "%s: can't power on device\n", __func__);  in __hwspin_lock_request()
696 		module_put(dev->driver->owner);  in __hwspin_lock_request()
706 	/* self-sanity check that should never fail */  in __hwspin_lock_request()
713  * hwspin_lock_get_id() - retrieve id number of a given hwspinlock
716  * Returns: the id number of a given @hwlock, or -EINVAL if @hwlock is invalid.
722 		return -EINVAL;  in hwspin_lock_get_id()
730  * hwspin_lock_request() - request an hwspinlock
732  * This function should be called by users of the hwspinlock device,
773  * hwspin_lock_request_specific() - request for a specific hwspinlock
774  * @id: index of the specific hwspinlock that is requested
777  * in order to assign them a specific hwspinlock.
779  * reserve specific hwspinlock ids for predefined purposes.
822  * hwspin_lock_free() - free a specific hwspinlock
823  * @hwlock: the specific hwspinlock to free
835 	struct device *dev;  in hwspin_lock_free()
841 		return -EINVAL;  in hwspin_lock_free()
844 	dev = hwlock->bank->dev;  in hwspin_lock_free()
853 		ret = -EINVAL;  in hwspin_lock_free()
857 	/* notify the underlying device that power is not needed */  in hwspin_lock_free()
867 	module_put(dev->driver->owner);  in hwspin_lock_free()
875 static int devm_hwspin_lock_match(struct device *dev, void *res, void *data)  in devm_hwspin_lock_match()
885 static void devm_hwspin_lock_release(struct device *dev, void *res)  in devm_hwspin_lock_release()
891  * devm_hwspin_lock_free() - free a specific hwspinlock for a managed device
892  * @dev: the device to free the specific hwspinlock
893  * @hwlock: the specific hwspinlock to free
903 int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock)  in devm_hwspin_lock_free()
916  * devm_hwspin_lock_request() - request an hwspinlock for a managed device
917  * @dev: the device to request an hwspinlock
919  * This function should be called by users of the hwspinlock device,
929 struct hwspinlock *devm_hwspin_lock_request(struct device *dev)  in devm_hwspin_lock_request()
950  * devm_hwspin_lock_request_specific() - request for a specific hwspinlock for
951  *					 a managed device
952  * @dev: the device to request the specific hwspinlock
953  * @id: index of the specific hwspinlock that is requested
956  * in order to assign them a specific hwspinlock.
958  * reserve specific hwspinlock ids for predefined purposes.
964 struct hwspinlock *devm_hwspin_lock_request_specific(struct device *dev,  in devm_hwspin_lock_request_specific()
986 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");