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Diffstat (limited to 'target/linux/ubicom32/files/arch/ubicom32/include/asm/semaphore.h')
| -rw-r--r-- | target/linux/ubicom32/files/arch/ubicom32/include/asm/semaphore.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/target/linux/ubicom32/files/arch/ubicom32/include/asm/semaphore.h b/target/linux/ubicom32/files/arch/ubicom32/include/asm/semaphore.h new file mode 100644 index 000000000..d20ead310 --- /dev/null +++ b/target/linux/ubicom32/files/arch/ubicom32/include/asm/semaphore.h @@ -0,0 +1,140 @@ +/* + * arch/ubicom32/include/asm/semaphore.h + * Interrupt-safe semaphores for Ubicom32 architecture. + * + * (C) Copyright 2009, Ubicom, Inc. + * (C) Copyright 1996 Linus Torvalds + * m68k version by Andreas Schwab + * Copyright (C) 2004 Microtronix Datacom Ltd + * + * This file is part of the Ubicom32 Linux Kernel Port. + * + * The Ubicom32 Linux Kernel Port is free software: you can redistribute + * it and/or modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, either version 2 of the + * License, or (at your option) any later version. + * + * The Ubicom32 Linux Kernel Port is distributed in the hope that it + * will be useful, but WITHOUT ANY WARRANTY; without even the implied + * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with the Ubicom32 Linux Kernel Port. If not, + * see <http://www.gnu.org/licenses/>. + * + * Ubicom32 implementation derived from (with many thanks): + * arch/m68knommu + * arch/blackfin + * arch/parisc + */ +#ifndef _ASM_UBICOM32_SEMAPHORE_H +#define _ASM_UBICOM32_SEMAPHORE_H + +#define RW_LOCK_BIAS 0x01000000 + +#ifndef __ASSEMBLY__ + +#include <linux/linkage.h> +#include <linux/wait.h> +#include <linux/spinlock.h> +#include <linux/rwsem.h> + +#include <asm/system.h> +#include <asm/atomic.h> + +struct semaphore { + atomic_t count; + atomic_t waking; + wait_queue_head_t wait; +}; + +#define __SEMAPHORE_INITIALIZER(name, n) \ +{ \ + .count = ATOMIC_INIT(n), \ + .waking = ATOMIC_INIT(0), \ + .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ +} + +#define __DECLARE_SEMAPHORE_GENERIC(name,count) \ + struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) + +#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) +#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) + +static inline void sema_init (struct semaphore *sem, int val) +{ + *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val); +} + +static inline void init_MUTEX (struct semaphore *sem) +{ + sema_init(sem, 1); +} + +static inline void init_MUTEX_LOCKED (struct semaphore *sem) +{ + sema_init(sem, 0); +} + +asmlinkage void __down_failed(void /* special register calling convention */); +asmlinkage int __down_failed_interruptible(void /* params in registers */); +asmlinkage int __down_failed_trylock(void /* params in registers */); +asmlinkage void __up_wakeup(void /* special register calling convention */); + +asmlinkage void __down(struct semaphore * sem); +asmlinkage int __down_interruptible(struct semaphore * sem); +asmlinkage int __down_trylock(struct semaphore * sem); +asmlinkage void __up(struct semaphore * sem); + +extern spinlock_t semaphore_wake_lock; + +/* + * This is ugly, but we want the default case to fall through. + * "down_failed" is a special asm handler that calls the C + * routine that actually waits. + */ +static inline void down(struct semaphore * sem) +{ + might_sleep(); + + if (atomic_dec_return(&sem->count) < 0) + __down(sem); +} + +static inline int down_interruptible(struct semaphore * sem) +{ + int ret = 0; + + + might_sleep(); + + if(atomic_dec_return(&sem->count) < 0) + ret = __down_interruptible(sem); + return ret; +} + +static inline int down_trylock(struct semaphore * sem) +{ + int ret = 0; + + if (atomic_dec_return (&sem->count) < 0) + ret = __down_trylock(sem); + return ret; +} + +/* + * Note! This is subtle. We jump to wake people up only if + * the semaphore was negative (== somebody was waiting on it). + * The default case (no contention) will result in NO + * jumps for both down() and up(). + */ +static inline void up(struct semaphore * sem) +{ + if (atomic_inc_return(&sem->count) <= 0) + __up(sem); +} + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_UBICOM32_SEMAPHORE_H */ |