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/* spinlock.h: 64-bit Sparc spinlock support.

 *

 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)

 */

#ifndef __SPARC64_SPINLOCK_H

#define __SPARC64_SPINLOCK_H

#include <linux/config.h>

#ifndef __ASSEMBLY__

/* To get debugging spinlocks which detect and catch

 * deadlock situations, set CONFIG_DEBUG_SPINLOCK

 * and rebuild your kernel.

 */

/* All of these locking primitives are expected to work properly

 * even in an RMO memory model, which currently is what the kernel

 * runs in.

 *

 * There is another issue.  Because we play games to save cycles

 * in the non-contention case, we need to be extra careful about

 * branch targets into the "spinning" code.  They live in their

 * own section, but the newer V9 branches have a shorter range

 * than the traditional 32-bit sparc branch variants.  The rule

 * is that the branches that go into and out of the spinner sections

 * must be pre-V9 branches.

 */

#ifndef CONFIG_DEBUG_SPINLOCK

typedef unsigned char spinlock_t;

#define SPIN_LOCK_UNLOCKED      0

#define spin_lock_init(lock)    (*((unsigned char *)(lock)) = 0)

#define spin_is_locked(lock)    (*((volatile unsigned char *)(lock)) != 0)

#define spin_unlock_wait(lock)  \

do {    membar("#LoadLoad");    \

} while(*((volatile unsigned char *)lock))

extern __inline__ void spin_lock(spinlock_t *lock)

{

        __asm__ __volatile__(

"1:     ldstub          [%0], %%g7\n"

"       brnz,pn         %%g7, 2f\n"

"        membar         #StoreLoad | #StoreStore\n"

"       .subsection     2\n"

"2:     ldub            [%0], %%g7\n"

"       brnz,pt         %%g7, 2b\n"

"        membar         #LoadLoad\n"

"       b,a,pt          %%xcc, 1b\n"

"       .previous\n"

        : /* no outputs */

        : "r" (lock)

        : "g7", "memory");

}

extern __inline__ int spin_trylock(spinlock_t *lock)

{

        unsigned int result;

        __asm__ __volatile__("ldstub [%1], %0\n\t"

                             "membar #StoreLoad | #StoreStore"

                             : "=r" (result)

                             : "r" (lock)

                             : "memory");

        return (result == 0);

}

extern __inline__ void spin_unlock(spinlock_t *lock)

{

        __asm__ __volatile__("membar    #StoreStore | #LoadStore\n\t"

                             "stb       %%g0, [%0]"

                             : /* No outputs */

                             : "r" (lock)

                             : "memory");

}

#else /* !(CONFIG_DEBUG_SPINLOCK) */

typedef struct {

        unsigned char lock;

        unsigned int owner_pc, owner_cpu;

} spinlock_t;

#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }

#define spin_lock_init(__lock)  \

do {    (__lock)->lock = 0; \

        (__lock)->owner_pc = 0; \

        (__lock)->owner_cpu = 0xff; \

} while(0)

#define spin_is_locked(__lock)  (*((volatile unsigned char *)(&((__lock)->lock))) != 0)

#define spin_unlock_wait(__lock)        \

do { \

        membar("#LoadLoad"); \

} while(*((volatile unsigned char *)(&((__lock)->lock))))

extern void _do_spin_lock (spinlock_t *lock, char *str);

extern void _do_spin_unlock (spinlock_t *lock);

extern int _spin_trylock (spinlock_t *lock);

#define spin_trylock(lp)        _spin_trylock(lp)

#define spin_lock(lock)         _do_spin_lock(lock, "spin_lock")

#define spin_unlock(lock)       _do_spin_unlock(lock)

#endif /* CONFIG_DEBUG_SPINLOCK */

/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */

#ifndef CONFIG_DEBUG_SPINLOCK

typedef unsigned int rwlock_t;

#define RW_LOCK_UNLOCKED        0

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

extern void __read_lock(rwlock_t *);

extern void __read_unlock(rwlock_t *);

extern void __write_lock(rwlock_t *);

extern void __write_unlock(rwlock_t *);

#define read_lock(p)    __read_lock(p)

#define read_unlock(p)  __read_unlock(p)

#define write_lock(p)   __write_lock(p)

#define write_unlock(p) __write_unlock(p)

#else /* !(CONFIG_DEBUG_SPINLOCK) */

typedef struct {

        unsigned long lock;

        unsigned int writer_pc, writer_cpu;

        unsigned int reader_pc[4];

} rwlock_t;

#define RW_LOCK_UNLOCKED        (rwlock_t) { 0, 0, 0xff, { 0, 0, 0, 0 } }

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

extern void _do_read_lock(rwlock_t *rw, char *str);

extern void _do_read_unlock(rwlock_t *rw, char *str);

extern void _do_write_lock(rwlock_t *rw, char *str);

extern void _do_write_unlock(rwlock_t *rw);

#define read_lock(lock) \

do {    unsigned long flags; \

        __save_and_cli(flags); \

        _do_read_lock(lock, "read_lock"); \

        __restore_flags(flags); \

} while(0)

#define read_unlock(lock) \

do {    unsigned long flags; \

        __save_and_cli(flags); \

        _do_read_unlock(lock, "read_unlock"); \

        __restore_flags(flags); \

} while(0)

#define write_lock(lock) \

do {    unsigned long flags; \

        __save_and_cli(flags); \

        _do_write_lock(lock, "write_lock"); \

        __restore_flags(flags); \

} while(0)

#define write_unlock(lock) \

do {    unsigned long flags; \

        __save_and_cli(flags); \

        _do_write_unlock(lock); \

        __restore_flags(flags); \

} while(0)

#endif /* CONFIG_DEBUG_SPINLOCK */

#endif /* !(__ASSEMBLY__) */

#endif /* !(__SPARC64_SPINLOCK_H) */