Import 2.3.18pre1

[davej-history.git] / include / asm-ppc / spinlock.h

#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H

/* Simple spin lock operations. There are two variants, one clears IRQ's
 * on the local processor, one does not.
 *
 * We make no fairness assumptions. They have a cost.
 */

typedefstruct{
volatileunsigned long lock;
volatileunsigned long owner_pc;
volatileunsigned long owner_cpu;
} spinlock_t;

#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0 }
#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0)
#define spin_unlock_wait(lp) do { barrier(); } while((lp)->lock)

externvoid_spin_lock(spinlock_t *lock);
externvoid_spin_unlock(spinlock_t *lock);
externintspin_trylock(spinlock_t *lock);

#define spin_lock(lp) _spin_lock(lp)
#define spin_unlock(lp) _spin_unlock(lp)

#define spin_lock_irq(lock) \
 do { __cli(); spin_lock(lock); } while (0)
#define spin_lock_bh(___lk) do { local_bh_disable(); spin_lock(___lk); } while(0)

#define spin_unlock_irq(lock) \
 do { spin_unlock(lock); __sti(); } while (0)
#define spin_unlock_bh(___lk) do { spin_unlock(___lk); local_bh_enable(); } while(0)

#define spin_lock_irqsave(lock, flags) \
 do { __save_flags(flags); __cli(); spin_lock(lock); } while (0)
#define spin_unlock_irqrestore(lock, flags) \
 do { spin_unlock(lock); __restore_flags(flags); } while (0)

externunsigned long__spin_trylock(volatileunsigned long*lock);

/*
 * Read-write spinlocks, allowing multiple readers
 * but only one writer.
 *
 * NOTE! it is quite common to have readers in interrupts
 * but no interrupt writers. For those circumstances we
 * can "mix" irq-safe locks - any writer needs to get a
 * irq-safe write-lock, but readers can get non-irqsafe
 * read-locks.
 */
typedefstruct{
volatileunsigned long lock;
volatileunsigned long owner_pc;
} rwlock_t;

#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }

externvoid_read_lock(rwlock_t *rw);
externvoid_read_unlock(rwlock_t *rw);
externvoid_write_lock(rwlock_t *rw);
externvoid_write_unlock(rwlock_t *rw);

#define read_lock(rw) _read_lock(rw)
#define write_lock(rw) _write_lock(rw)
#define write_unlock(rw) _write_unlock(rw)
#define read_unlock(rw) _read_unlock(rw)

#endif/* __ASM_SPINLOCK_H */