mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 05:41:55 +00:00
146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
#ifndef _ASM_M32R_SEMAPHORE_H
|
|
#define _ASM_M32R_SEMAPHORE_H
|
|
|
|
#include <linux/linkage.h>
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
/*
|
|
* SMP- and interrupt-safe semaphores..
|
|
*
|
|
* Copyright (C) 1996 Linus Torvalds
|
|
* Copyright (C) 2004, 2006 Hirokazu Takata <takata at linux-m32r.org>
|
|
*/
|
|
|
|
#include <linux/wait.h>
|
|
#include <linux/rwsem.h>
|
|
#include <asm/assembler.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 __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 doesnt. 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);
|
|
}
|
|
|
|
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);
|
|
|
|
/*
|
|
* Atomically decrement the semaphore's count. If it goes negative,
|
|
* block the calling thread in the TASK_UNINTERRUPTIBLE state.
|
|
*/
|
|
static inline void down(struct semaphore * sem)
|
|
{
|
|
might_sleep();
|
|
if (unlikely(atomic_dec_return(&sem->count) < 0))
|
|
__down(sem);
|
|
}
|
|
|
|
/*
|
|
* Interruptible try to acquire a semaphore. If we obtained
|
|
* it, return zero. If we were interrupted, returns -EINTR
|
|
*/
|
|
static inline int down_interruptible(struct semaphore * sem)
|
|
{
|
|
int result = 0;
|
|
|
|
might_sleep();
|
|
if (unlikely(atomic_dec_return(&sem->count) < 0))
|
|
result = __down_interruptible(sem);
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* Non-blockingly attempt to down() a semaphore.
|
|
* Returns zero if we acquired it
|
|
*/
|
|
static inline int down_trylock(struct semaphore * sem)
|
|
{
|
|
unsigned long flags;
|
|
long count;
|
|
int result = 0;
|
|
|
|
local_irq_save(flags);
|
|
__asm__ __volatile__ (
|
|
"# down_trylock \n\t"
|
|
DCACHE_CLEAR("%0", "r4", "%1")
|
|
M32R_LOCK" %0, @%1; \n\t"
|
|
"addi %0, #-1; \n\t"
|
|
M32R_UNLOCK" %0, @%1; \n\t"
|
|
: "=&r" (count)
|
|
: "r" (&sem->count)
|
|
: "memory"
|
|
#ifdef CONFIG_CHIP_M32700_TS1
|
|
, "r4"
|
|
#endif /* CONFIG_CHIP_M32700_TS1 */
|
|
);
|
|
local_irq_restore(flags);
|
|
|
|
if (unlikely(count < 0))
|
|
result = __down_trylock(sem);
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* 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 (unlikely(atomic_inc_return(&sem->count) <= 0))
|
|
__up(sem);
|
|
}
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _ASM_M32R_SEMAPHORE_H */
|