| /* On the i386 these are coded in asm, perhaps we should as well. Later.. */ |
| |
| #ifndef _CRIS_SEMAPHORE_H |
| #define _CRIS_SEMAPHORE_H |
| |
| #define RW_LOCK_BIAS 0x01000000 |
| |
| #include <linux/wait.h> |
| #include <linux/spinlock.h> |
| #include <linux/rwsem.h> |
| |
| #include <asm/system.h> |
| #include <asm/atomic.h> |
| |
| /* |
| * CRIS semaphores, implemented in C-only so far. |
| */ |
| |
| int printk(const char *fmt, ...); |
| |
| struct semaphore { |
| int count; /* not atomic_t since we do the atomicity here already */ |
| 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) \ |
| { 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) |
| { |
| *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); |
| } |
| |
| extern inline void init_MUTEX (struct semaphore *sem) |
| { |
| sema_init(sem, 1); |
| } |
| |
| extern 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); |
| |
| /* notice - we probably can do cli/sti here instead of saving */ |
| |
| extern inline void down(struct semaphore * sem) |
| { |
| unsigned long flags; |
| int failed; |
| |
| #if WAITQUEUE_DEBUG |
| CHECK_MAGIC(sem->__magic); |
| #endif |
| |
| /* atomically decrement the semaphores count, and if its negative, we wait */ |
| save_flags(flags); |
| cli(); |
| failed = --(sem->count) < 0; |
| restore_flags(flags); |
| if(failed) { |
| __down(sem); |
| } |
| } |
| |
| /* |
| * This version waits in interruptible state so that the waiting |
| * process can be killed. The down_interruptible routine |
| * returns negative for signalled and zero for semaphore acquired. |
| */ |
| |
| extern inline int down_interruptible(struct semaphore * sem) |
| { |
| unsigned long flags; |
| int failed; |
| |
| #if WAITQUEUE_DEBUG |
| CHECK_MAGIC(sem->__magic); |
| #endif |
| |
| /* atomically decrement the semaphores count, and if its negative, we wait */ |
| save_flags(flags); |
| cli(); |
| failed = --(sem->count) < 0; |
| restore_flags(flags); |
| if(failed) |
| failed = __down_interruptible(sem); |
| return(failed); |
| } |
| |
| extern inline int down_trylock(struct semaphore * sem) |
| { |
| unsigned long flags; |
| int failed; |
| |
| #if WAITQUEUE_DEBUG |
| CHECK_MAGIC(sem->__magic); |
| #endif |
| |
| save_flags(flags); |
| cli(); |
| failed = --(sem->count) < 0; |
| restore_flags(flags); |
| if(failed) |
| failed = __down_trylock(sem); |
| return(failed); |
| } |
| |
| /* |
| * 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(). |
| */ |
| extern inline void up(struct semaphore * sem) |
| { |
| unsigned long flags; |
| int wakeup; |
| |
| #if WAITQUEUE_DEBUG |
| CHECK_MAGIC(sem->__magic); |
| #endif |
| |
| /* atomically increment the semaphores count, and if it was negative, we wake people */ |
| save_flags(flags); |
| cli(); |
| wakeup = ++(sem->count) <= 0; |
| restore_flags(flags); |
| if(wakeup) { |
| __up(sem); |
| } |
| } |
| |
| static inline int sem_getcount(struct semaphore *sem) |
| { |
| return sem->count; |
| } |
| |
| #endif |