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#ifndef _PPC_SEMAPHORE_H
#define _PPC_SEMAPHORE_H
/*
* Swiped from asm-sparc/semaphore.h and modified
* -- Cort (cort@cs.nmt.edu)
*
* Stole some rw spinlock-based semaphore stuff from asm-alpha/semaphore.h
* -- Ani Joshi (ajoshi@unixbox.com)
*/
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
struct semaphore {
atomic_t count;
atomic_t waking;
wait_queue_head_t wait;
#if WAITQUEUE_DEBUG
long __magic;
#endif
};
#if WAITQUEUE_DEBUG
# define __SEM_DEBUG_INIT(name) \
, (long)&(name).__magic
#else
# define __SEM_DEBUG_INIT(name)
#endif
#define __SEMAPHORE_INITIALIZER(name,count) \
{ ATOMIC_INIT(count), ATOMIC_INIT(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)
{
atomic_set(&sem->count, val);
atomic_set(&sem->waking, 0);
init_waitqueue_head(&sem->wait);
#if WAITQUEUE_DEBUG
sem->__magic = (long)&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);
}
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern int __down_trylock(struct semaphore * sem);
extern void __up(struct semaphore * sem);
extern inline void down(struct semaphore * sem)
{
if (atomic_dec_return(&sem->count) >= 0)
wmb();
else
__down(sem);
}
extern inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
if (atomic_dec_return(&sem->count) >= 0)
wmb();
else
ret = __down_interruptible(sem);
return ret;
}
extern inline int down_trylock(struct semaphore * sem)
{
int ret = 0;
if (atomic_dec_return(&sem->count) >= 0)
wmb();
else
ret = __down_trylock(sem);
return ret;
}
extern inline void up(struct semaphore * sem)
{
mb();
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
/* RW spinlock-based semaphores */
struct rw_semaphore
{
spinlock_t lock;
int rd, wr;
wait_queue_head_t wait;
#if WAITQUEUE_DEBUG
long __magic;
#endif
};
#define RW_LOCK_BIAS 2 /* XXX bogus */
#define __RWSEM_INITIALIZER(name, count) \
{ \
SPIN_LOCK_UNLOCKED, \
(count) == 1, (count) == 0, \
__WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
__SEM_DEBUG_INIT(name) \
}
#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)
{
spin_lock_init(&sem->lock);
sem->rd = sem->wr = 0;
init_waitqueue_head(&sem->wait);
#if WAITQUEUE_DEBUG
sem->__magic = (long)&sem->__magic;
#endif
}
#ifndef CHECK_MAGIC
#define CHECK_MAGIC(x)
#endif
extern void down_read_failed(struct rw_semaphore *);
extern void down_write_failed(struct rw_semaphore *);
extern inline void down_read(struct rw_semaphore *sem)
{
CHECK_MAGIC(sem->__magic);
spin_lock_irq(&sem->lock);
if (sem->wr)
down_read_failed(sem);
sem->rd++;
spin_unlock_irq(&sem->lock);
}
extern inline void down_write(struct rw_semaphore *sem)
{
CHECK_MAGIC(sem->__magic);
spin_lock(&sem->lock);
if(sem->rd || sem->wr)
down_write_failed(sem);
sem->wr = 1;
spin_unlock(&sem->lock);
}
#define up_read(sem) \
do { \
unsigned long flags; \
\
CHECK_MAGIC((sem)->__magic); \
\
spin_lock_irqsave(&(sem)->lock, flags); \
if (!--(sem)->rd && waitqueue_active(&(sem)->wait)) \
wake_up(&(sem)->wait); \
spin_unlock_irqrestore(&(sem)->lock, flags); \
} while (0)
#define up_write(sem) \
do { \
unsigned long flags; \
\
CHECK_MAGIC((sem)->__magic); \
\
spin_lock_irqsave(&(sem)->lock, flags); \
(sem)->wr = 0; \
if (waitqueue_active(&(sem)->wait)) \
wake_up(&(sem)->wait); \
spin_unlock_irqrestore(&(sem)->lock, flags); \
} while (0)
#endif /* __KERNEL__ */
#endif /* !(_PPC_SEMAPHORE_H) */
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