Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  include/asm-s390/spinlock.h

 *

 *  S390 version

 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation

 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)

 *

 *  Derived from "include/asm-i386/spinlock.h"

 */

#ifndef __ASM_SPINLOCK_H

#define __ASM_SPINLOCK_H

#include <linux/smp.h>

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)

static inline int

_raw_compare_and_swap(volatile unsigned int *lock,

                      unsigned int old, unsigned int new)

{

        asm volatile(

                "       cs      %0,%3,%1"

                : "=d" (old), "=Q" (*lock)

                : "0" (old), "d" (new), "Q" (*lock)

                : "cc", "memory" );

        return old;

}

#else /* __GNUC__ */

static inline int

_raw_compare_and_swap(volatile unsigned int *lock,

                      unsigned int old, unsigned int new)

{

        asm volatile(

                "       cs      %0,%3,0(%4)"

                : "=d" (old), "=m" (*lock)

                : "0" (old), "d" (new), "a" (lock), "m" (*lock)

                : "cc", "memory" );

        return old;

}

#endif /* __GNUC__ */

/*

 * 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.

 *

 * (the type definitions are in asm/spinlock_types.h)

 */

#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)

#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)

#define __raw_spin_unlock_wait(lock) \

        do { while (__raw_spin_is_locked(lock)) \

                 _raw_spin_relax(lock); } while (0)

extern void _raw_spin_lock_wait(raw_spinlock_t *, unsigned int pc);

extern int _raw_spin_trylock_retry(raw_spinlock_t *, unsigned int pc);

extern void _raw_spin_relax(raw_spinlock_t *lock);

static inline void __raw_spin_lock(raw_spinlock_t *lp)

{

        unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);

        int old;

        old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());

        if (likely(old == 0)) {

                lp->owner_pc = pc;

                return;

        }

        _raw_spin_lock_wait(lp, pc);

}

static inline int __raw_spin_trylock(raw_spinlock_t *lp)

{

        unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);

        int old;

        old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());

        if (likely(old == 0)) {

                lp->owner_pc = pc;

                return 1;

        }

        return _raw_spin_trylock_retry(lp, pc);

}

static inline void __raw_spin_unlock(raw_spinlock_t *lp)

{

        lp->owner_pc = 0;

        _raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);

}

/*

 * 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.

 */

/**

 * read_can_lock - would read_trylock() succeed?

 * @lock: the rwlock in question.

 */

#define __raw_read_can_lock(x) ((int)(x)->lock >= 0)

/**

 * write_can_lock - would write_trylock() succeed?

 * @lock: the rwlock in question.

 */

#define __raw_write_can_lock(x) ((x)->lock == 0)

extern void _raw_read_lock_wait(raw_rwlock_t *lp);

extern int _raw_read_trylock_retry(raw_rwlock_t *lp);

extern void _raw_write_lock_wait(raw_rwlock_t *lp);

extern int _raw_write_trylock_retry(raw_rwlock_t *lp);

static inline void __raw_read_lock(raw_rwlock_t *rw)

{

        unsigned int old;

        old = rw->lock & 0x7fffffffU;

        if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)

                _raw_read_lock_wait(rw);

}

static inline void __raw_read_unlock(raw_rwlock_t *rw)

{

        unsigned int old, cmp;

        old = rw->lock;

        do {

                cmp = old;

                old = _raw_compare_and_swap(&rw->lock, old, old - 1);

        } while (cmp != old);

}

static inline void __raw_write_lock(raw_rwlock_t *rw)

{

        if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))

                _raw_write_lock_wait(rw);

}

static inline void __raw_write_unlock(raw_rwlock_t *rw)

{

        _raw_compare_and_swap(&rw->lock, 0x80000000, 0);

}

static inline int __raw_read_trylock(raw_rwlock_t *rw)

{

        unsigned int old;

        old = rw->lock & 0x7fffffffU;

        if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old))

                return 1;

        return _raw_read_trylock_retry(rw);

}

static inline int __raw_write_trylock(raw_rwlock_t *rw)

{

        if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))

                return 1;

        return _raw_write_trylock_retry(rw);

}

#define _raw_read_relax(lock)   cpu_relax()

#define _raw_write_relax(lock)  cpu_relax()

#endif /* __ASM_SPINLOCK_H */