#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H

#include <asm/system.h>

/* Note that PA-RISC has to use `1' to mean unlocked and `0' to mean locked
 * since it only has load-and-zero. Moreover, at least on some PA processors,
 * the semaphore address has to be 16-byte aligned.
 */

#ifndef CONFIG_DEBUG_SPINLOCK

#define __SPIN_LOCK_UNLOCKED    { { 1, 1, 1, 1 } }
#undef SPIN_LOCK_UNLOCKED
#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED

#define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)

static inline int spin_is_locked(spinlock_t *x)
{
        volatile unsigned int *a = __ldcw_align(x);
        return *a == 0;
}

#define spin_unlock_wait(x)     do { barrier(); } while(spin_is_locked(x))
#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)

static inline void _raw_spin_lock(spinlock_t *x)
{
        volatile unsigned int *a = __ldcw_align(x);
        while (__ldcw(a) == 0)
                while (*a == 0);
}

static inline void _raw_spin_unlock(spinlock_t *x)
{
        volatile unsigned int *a = __ldcw_align(x);
        *a = 1;
}

static inline int _raw_spin_trylock(spinlock_t *x)
{
        volatile unsigned int *a = __ldcw_align(x);
        return __ldcw(a) != 0;
}
        
#define spin_lock_own(LOCK, LOCATION)   ((void)0)

#else /* !(CONFIG_DEBUG_SPINLOCK) */

#define SPINLOCK_MAGIC  0x1D244B3C

#define __SPIN_LOCK_UNLOCKED    { { 1, 1, 1, 1 }, SPINLOCK_MAGIC, 10, __FILE__ , NULL, 0, -1, NULL, NULL }
#undef SPIN_LOCK_UNLOCKED
#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED

#define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)

#define CHECK_LOCK(x)                                                   \
        do {                                                            \
                if (unlikely((x)->magic != SPINLOCK_MAGIC)) {                   \
                        printk(KERN_ERR "%s:%d: spin_is_locked"         \
                        " on uninitialized spinlock %p.\n",             \
                                __FILE__, __LINE__, (x));               \
                }                                                       \
        } while(0)

#define spin_is_locked(x)                                               \
        ({                                                              \
                CHECK_LOCK(x);                                          \
                volatile unsigned int *a = __ldcw_align(x);             \
                if (unlikely((*a == 0) && (x)->babble)) {                               \
                        (x)->babble--;                                  \
                        printk("KERN_WARNING                            \
                                %s:%d: spin_is_locked(%s/%p) already"   \
                                " locked by %s:%d in %s at %p(%d)\n",   \
                                __FILE__,__LINE__, (x)->module, (x),    \
                                (x)->bfile, (x)->bline, (x)->task->comm,\
                                (x)->previous, (x)->oncpu);             \
                }                                                       \
                *a == 0;                                                \
        })

#define spin_unlock_wait(x)                                             \
        do {                                                            \
                CHECK_LOCK(x);                                          \
                volatile unsigned int *a = __ldcw_align(x);             \
                if (unlikely((*a == 0) && (x)->babble)) {                               \
                        (x)->babble--;                                  \
                        printk("KERN_WARNING                            \
                                %s:%d: spin_unlock_wait(%s/%p)"         \
                                " owned by %s:%d in %s at %p(%d)\n",    \
                                __FILE__,__LINE__, (x)->module, (x),    \
                                (x)->bfile, (x)->bline, (x)->task->comm,\
                                (x)->previous, (x)->oncpu);             \
                }                                                       \
                barrier();                                              \
        } while (*((volatile unsigned char *)(__ldcw_align(x))) == 0)

extern void _dbg_spin_lock(spinlock_t *lock, const char *base_file, int line_no);
extern void _dbg_spin_unlock(spinlock_t *lock, const char *, int);
extern int _dbg_spin_trylock(spinlock_t * lock, const char *, int);

#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)

#define _raw_spin_unlock(lock)  _dbg_spin_unlock(lock, __FILE__, __LINE__)
#define _raw_spin_lock(lock) _dbg_spin_lock(lock, __FILE__, __LINE__)
#define _raw_spin_trylock(lock) _dbg_spin_trylock(lock, __FILE__, __LINE__)

/* just in case we need it */
#define spin_lock_own(LOCK, LOCATION)                                   \
do {                                                                    \
        volatile unsigned int *a = __ldcw_align(LOCK);                  \
        if (!((*a == 0) && ((LOCK)->oncpu == smp_processor_id())))      \
                printk("KERN_WARNING                                    \
                        %s: called on %d from %p but lock %s on %d\n",  \
                        LOCATION, smp_processor_id(),                   \
                        __builtin_return_address(0),                    \
                        (*a == 0) ? "taken" : "freed", (LOCK)->on_cpu); \
} while (0)

#endif /* !(CONFIG_DEBUG_SPINLOCK) */

/*
 * Read-write spinlocks, allowing multiple readers
 * but only one writer.
 */
typedef struct {
        spinlock_t lock;
        volatile int counter;
} rwlock_t;

#define RW_LOCK_UNLOCKED (rwlock_t) { __SPIN_LOCK_UNLOCKED, 0 }

#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0)

#define rwlock_is_locked(lp) ((lp)->counter != 0)

/* read_lock, read_unlock are pretty straightforward.  Of course it somehow
 * sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */

#ifdef CONFIG_DEBUG_RWLOCK
extern void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline);
#define _raw_read_lock(rw) _dbg_read_lock(rw, __FILE__, __LINE__)
#else
static  __inline__ void _raw_read_lock(rwlock_t *rw)
{
        unsigned long flags;
        local_irq_save(flags);
        _raw_spin_lock(&rw->lock); 

        rw->counter++;

        _raw_spin_unlock(&rw->lock);
        local_irq_restore(flags);
}
#endif  /* CONFIG_DEBUG_RWLOCK */

static  __inline__ void _raw_read_unlock(rwlock_t *rw)
{
        unsigned long flags;
        local_irq_save(flags);
        _raw_spin_lock(&rw->lock); 

        rw->counter--;

        _raw_spin_unlock(&rw->lock);
        local_irq_restore(flags);
}

/* write_lock is less trivial.  We optimistically grab the lock and check
 * if we surprised any readers.  If so we release the lock and wait till
 * they're all gone before trying again
 *
 * Also note that we don't use the _irqsave / _irqrestore suffixes here.
 * If we're called with interrupts enabled and we've got readers (or other
 * writers) in interrupt handlers someone fucked up and we'd dead-lock
 * sooner or later anyway.   prumpf */

#ifdef CONFIG_DEBUG_RWLOCK
extern void _dbg_write_lock(rwlock_t * rw, const char *bfile, int bline);
#define _raw_write_lock(rw) _dbg_write_lock(rw, __FILE__, __LINE__)
#else
static  __inline__ void _raw_write_lock(rwlock_t *rw)
{
retry:
        _raw_spin_lock(&rw->lock);

        if(rw->counter != 0) {
                /* this basically never happens */
                _raw_spin_unlock(&rw->lock);

                while(rw->counter != 0);

                goto retry;
        }

        /* got it.  now leave without unlocking */
        rw->counter = -1; /* remember we are locked */
}
#endif /* CONFIG_DEBUG_RWLOCK */

/* write_unlock is absolutely trivial - we don't have to wait for anything */

static  __inline__ void _raw_write_unlock(rwlock_t *rw)
{
        rw->counter = 0;
        _raw_spin_unlock(&rw->lock);
}

static __inline__ int is_read_locked(rwlock_t *rw)
{
        return rw->counter > 0;
}

static __inline__ int is_write_locked(rwlock_t *rw)
{
        return rw->counter < 0;
}

#endif /* __ASM_SPINLOCK_H */