diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-sh/semaphore.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-sh/semaphore.h')
-rw-r--r-- | include/asm-sh/semaphore.h | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/include/asm-sh/semaphore.h b/include/asm-sh/semaphore.h new file mode 100644 index 00000000000..b923a77a8a7 --- /dev/null +++ b/include/asm-sh/semaphore.h @@ -0,0 +1,119 @@ +#ifndef __ASM_SH_SEMAPHORE_H +#define __ASM_SH_SEMAPHORE_H + +#include <linux/linkage.h> + +#ifdef __KERNEL__ +/* + * SMP- and interrupt-safe semaphores. + * + * (C) Copyright 1996 Linus Torvalds + * + * SuperH verison by Niibe Yutaka + * (Currently no asm implementation but generic C code...) + */ + +#include <linux/spinlock.h> +#include <linux/rwsem.h> +#include <linux/wait.h> + +#include <asm/system.h> +#include <asm/atomic.h> + +struct semaphore { + atomic_t count; + int sleepers; + wait_queue_head_t wait; +}; + +#define __SEMAPHORE_INITIALIZER(name, n) \ +{ \ + .count = ATOMIC_INIT(n), \ + .sleepers = 0, \ + .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ +} + +#define __MUTEX_INITIALIZER(name) \ + __SEMAPHORE_INITIALIZER(name,1) + +#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); + * + * i'd rather use the more flexible initialization above, but sadly + * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well. + */ + atomic_set(&sem->count, val); + sem->sleepers = 0; + init_waitqueue_head(&sem->wait); +} + +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); +} + +#if 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 */); +#endif + +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; + +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). + */ +static inline void up(struct semaphore * sem) +{ + if (atomic_inc_return(&sem->count) <= 0) + __up(sem); +} + +#endif +#endif /* __ASM_SH_SEMAPHORE_H */ |