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#ifndef __ASM_SH_SEMAPHORE_H
#define __ASM_SH_SEMAPHORE_H
#include <linux/linkage.h>
/*
* 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 <asm/system.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
#if WAITQUEUE_DEBUG
long __magic;
#endif
};
#if WAITQUEUE_DEBUG
# define __SEM_DEBUG_INIT(name) \
, (int)&(name).__magic
#else
# define __SEM_DEBUG_INIT(name)
#endif
#define __SEMAPHORE_INITIALIZER(name,count) \
{ ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
__SEM_DEBUG_INIT(name) }
#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)
extern 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);
#if WAITQUEUE_DEBUG
sem->__magic = (int)&sem->__magic;
#endif
}
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 struct rw_semaphore *__down_read(struct rw_semaphore *sem, int carry);
extern struct rw_semaphore *__down_write(struct rw_semaphore *sem, int carry);
asmlinkage struct rw_semaphore *__rwsem_wake(struct rw_semaphore *sem);
extern spinlock_t semaphore_wake_lock;
extern __inline__ void down(struct semaphore * sem)
{
#if WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
extern __inline__ int down_interruptible(struct semaphore * sem)
{
int ret = 0;
#if WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
if (atomic_dec_return(&sem->count) < 0)
ret = __down_interruptible(sem);
return ret;
}
extern __inline__ int down_trylock(struct semaphore * sem)
{
int ret = 0;
#if WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
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).
*/
extern __inline__ void up(struct semaphore * sem)
{
#if WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
/* rw mutexes (should that be mutices? =) -- throw rw
* spinlocks and semaphores together, and this is what we
* end up with...
*
* SuperH version by Niibe Yutaka
*/
struct rw_semaphore {
atomic_t count;
volatile unsigned char write_bias_granted;
volatile unsigned char read_bias_granted;
volatile unsigned char pad1;
volatile unsigned char pad2;
wait_queue_head_t wait;
wait_queue_head_t write_bias_wait;
#if WAITQUEUE_DEBUG
long __magic;
atomic_t readers;
atomic_t writers;
#endif
};
#define RW_LOCK_BIAS 0x01000000
#if WAITQUEUE_DEBUG
#define __RWSEM_DEBUG_INIT , ATOMIC_INIT(0), ATOMIC_INIT(0)
#else
#define __RWSEM_DEBUG_INIT /* */
#endif
#define __RWSEM_INITIALIZER(name,count) \
{ ATOMIC_INIT(count), 0, 0, 0, 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
__WAIT_QUEUE_HEAD_INITIALIZER((name).write_bias_wait) \
__SEM_DEBUG_INIT(name) __RWSEM_DEBUG_INIT }
#define __DECLARE_RWSEM_GENERIC(name,count) \
struct rw_semaphore name = __RWSEM_INITIALIZER(name,count)
#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS)
#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1)
#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0)
extern inline void init_rwsem(struct rw_semaphore *sem)
{
atomic_set(&sem->count, RW_LOCK_BIAS);
sem->read_bias_granted = 0;
sem->write_bias_granted = 0;
init_waitqueue_head(&sem->wait);
init_waitqueue_head(&sem->write_bias_wait);
#if WAITQUEUE_DEBUG
sem->__magic = (long)&sem->__magic;
atomic_set(&sem->readers, 0);
atomic_set(&sem->writers, 0);
#endif
}
extern inline void down_read(struct rw_semaphore *sem)
{
int saved = atomic_read(&sem->count), new;
#if WAITQUEUE_DEBUG
if (sem->__magic != (long)&sem->__magic)
BUG();
#endif
if ((new = atomic_dec_return(&sem->count)) < 0)
__down_read(sem, (new < 0 && saved >=0));
#if WAITQUEUE_DEBUG
if (sem->write_bias_granted)
BUG();
if (atomic_read(&sem->writers))
BUG();
atomic_inc(&sem->readers);
#endif
}
extern inline void down_write(struct rw_semaphore *sem)
{
int saved = atomic_read(&sem->count), new;
#if WAITQUEUE_DEBUG
if (sem->__magic != (long)&sem->__magic)
BUG();
#endif
if ((new = atomic_sub_return(RW_LOCK_BIAS, &sem->count)) != 0)
__down_write(sem, (new < 0 && saved >=0));
#if WAITQUEUE_DEBUG
if (atomic_read(&sem->writers))
BUG();
if (atomic_read(&sem->readers))
BUG();
if (sem->read_bias_granted)
BUG();
if (sem->write_bias_granted)
BUG();
atomic_inc(&sem->writers);
#endif
}
/* When a reader does a release, the only significant
* case is when there was a writer waiting, and we've
* bumped the count to 0: we must wake the writer up.
*/
extern inline void __up_read(struct rw_semaphore *sem)
{
if (atomic_inc_return(&sem->count) == 0)
__rwsem_wake(sem);
}
/* releasing the writer is easy -- just release it and
* wake up any sleepers.
*/
extern inline void __up_write(struct rw_semaphore *sem)
{
int saved = atomic_read(&sem->count), new;
new = atomic_add_return(RW_LOCK_BIAS, &sem->count);
if (saved < 0 && new >= 0)
__rwsem_wake(sem);
}
extern inline void up_read(struct rw_semaphore *sem)
{
#if WAITQUEUE_DEBUG
if (sem->write_bias_granted)
BUG();
if (atomic_read(&sem->writers))
BUG();
atomic_dec(&sem->readers);
#endif
__up_read(sem);
}
extern inline void up_write(struct rw_semaphore *sem)
{
#if WAITQUEUE_DEBUG
if (sem->read_bias_granted)
BUG();
if (sem->write_bias_granted)
BUG();
if (atomic_read(&sem->readers))
BUG();
if (atomic_read(&sem->writers) != 1)
BUG();
atomic_dec(&sem->writers);
#endif
__up_write(sem);
}
#endif /* __ASM_SH_SEMAPHORE_H */
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