4  * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
6  * Contact: Ohad Ben-Cohen <ohad@wizery.com>
26 #include <linux/radix-tree.h>
39  * and provides easy-to-use API which makes the hwspinlock core code simple
57  * as the radix-tree API requires that users provide all synchronisation.
58  * A mutex is needed because we're using non-atomic radix tree allocations.
64  * __hwspin_trylock() - attempt to lock a specific hwspinlock
76  * minimize remote cores polling on the hardware interconnect.
84  * Returns 0 if we successfully locked the hwspinlock or -EBUSY if
100 	 *    to minimize the possible polling on the hardware interconnect  in __hwspin_trylock()
102 	 * 2. Make the hwspinlock SMP-safe (so we can take it from  in __hwspin_trylock()
109 		ret = spin_trylock_irqsave(&hwlock->lock, *flags);  in __hwspin_trylock()
111 		ret = spin_trylock_irq(&hwlock->lock);  in __hwspin_trylock()
113 		ret = spin_trylock(&hwlock->lock);  in __hwspin_trylock()
117 		return -EBUSY;  in __hwspin_trylock()
120 	ret = hwlock->bank->ops->trylock(hwlock);  in __hwspin_trylock()
125 			spin_unlock_irqrestore(&hwlock->lock, *flags);  in __hwspin_trylock()
127 			spin_unlock_irq(&hwlock->lock);  in __hwspin_trylock()
129 			spin_unlock(&hwlock->lock);  in __hwspin_trylock()
131 		return -EBUSY;  in __hwspin_trylock()
151  * __hwspin_lock_timeout() - lock an hwspinlock with timeout limit
166  * hardware interconnect.
174  * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still
188 		if (ret != -EBUSY)  in __hwspin_lock_timeout()
196 			return -ETIMEDOUT;  in __hwspin_lock_timeout()
199 		 * Allow platform-specific relax handlers to prevent  in __hwspin_lock_timeout()
200 		 * hogging the interconnect (no sleeping, though)  in __hwspin_lock_timeout()
202 		if (hwlock->bank->ops->relax)  in __hwspin_lock_timeout()
203 			hwlock->bank->ops->relax(hwlock);  in __hwspin_lock_timeout()
211  * __hwspin_unlock() - unlock a specific hwspinlock
212  * @hwlock: a previously-acquired hwspinlock which we want to unlock
248 	hwlock->bank->ops->unlock(hwlock);  in __hwspin_unlock()
252 		spin_unlock_irqrestore(&hwlock->lock, *flags);  in __hwspin_unlock()
254 		spin_unlock_irq(&hwlock->lock);  in __hwspin_unlock()
256 		spin_unlock(&hwlock->lock);  in __hwspin_unlock()
269 		if (ret == -EEXIST)  in hwspin_lock_register_single()
277 	/* self-sanity check which should never fail */  in hwspin_lock_register_single()
311  * hwspin_lock_register() - register a new hw spinlock device
318  * This function should be called from the underlying platform-specific
331 	if (!bank || !ops || !dev || !num_locks || !ops->trylock ||  in hwspin_lock_register()
332 							!ops->unlock) {  in hwspin_lock_register()
334 		return -EINVAL;  in hwspin_lock_register()
337 	bank->dev = dev;  in hwspin_lock_register()
338 	bank->ops = ops;  in hwspin_lock_register()
339 	bank->base_id = base_id;  in hwspin_lock_register()
340 	bank->num_locks = num_locks;  in hwspin_lock_register()
343 		hwlock = &bank->lock[i];  in hwspin_lock_register()
345 		spin_lock_init(&hwlock->lock);  in hwspin_lock_register()
346 		hwlock->bank = bank;  in hwspin_lock_register()
356 	while (--i >= 0)  in hwspin_lock_register()
363  * hwspin_lock_unregister() - unregister an hw spinlock device
366  * This function should be called from the underlying platform-specific
378 	for (i = 0; i < bank->num_locks; i++) {  in hwspin_lock_unregister()
379 		hwlock = &bank->lock[i];  in hwspin_lock_unregister()
381 		tmp = hwspin_lock_unregister_single(bank->base_id + i);  in hwspin_lock_unregister()
383 			return -EBUSY;  in hwspin_lock_unregister()
385 		/* self-sanity check that should never fail */  in hwspin_lock_unregister()
394  * __hwspin_lock_request() - tag an hwspinlock as used and power it up
405 	struct device *dev = hwlock->bank->dev;  in __hwspin_lock_request()
410 	if (!try_module_get(dev->driver->owner)) {  in __hwspin_lock_request()
412 		return -EINVAL;  in __hwspin_lock_request()
426 	/* self-sanity check that should never fail */  in __hwspin_lock_request()
433  * hwspin_lock_get_id() - retrieve id number of a given hwspinlock
436  * Returns the id number of a given @hwlock, or -EINVAL if @hwlock is invalid.
442 		return -EINVAL;  in hwspin_lock_get_id()
450  * hwspin_lock_request() - request an hwspinlock
493  * hwspin_lock_request_specific() - request for a specific hwspinlock
542  * hwspin_lock_free() - free a specific hwspinlock
555 	struct device *dev = hwlock->bank->dev;  in hwspin_lock_free()
561 		return -EINVAL;  in hwspin_lock_free()
572 		ret = -EINVAL;  in hwspin_lock_free()
588 	module_put(dev->driver->owner);  in hwspin_lock_free()
598 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");