atomic.h

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/* atomic.h: atomic operation emulation for FR-V
 *
 * For an explanation of how atomic ops work in this arch, see:
 *   Documentation/frv/atomic-ops.txt
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H

#include <linux/types.h>
#include <asm/spr-regs.h>
#include <asm/cmpxchg.h>

#ifdef CONFIG_SMP
#error not SMP safe
#endif

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 *
 * We do not have SMP systems, so we don't have to deal with that.
 */

/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec()  barrier()
#define smp_mb__before_atomic_inc() barrier()
#define smp_mb__after_atomic_inc()  barrier()

#define ATOMIC_INIT(i)      { (i) }
#define atomic_read(v)      (*(volatile int *)&(v)->counter)
#define atomic_set(v, i)    (((v)->counter) = (i))

#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
static inline int atomic_add_return(int i, atomic_t *v)
{
    unsigned long val;

    asm("0:                     \n"
        "   orcc        gr0,gr0,gr0,icc3    \n" /* set ICC3.Z */
        "   ckeq        icc3,cc7        \n"
        "   ld.p        %M0,%1          \n" /* LD.P/ORCR must be atomic */
        "   orcr        cc7,cc7,cc3     \n" /* set CC3 to true */
        "   add%I2      %1,%2,%1        \n"
        "   cst.p       %1,%M0      ,cc3,#1 \n"
        "   corcc       gr29,gr29,gr0   ,cc3,#1 \n" /* clear ICC3.Z if store happens */
        "   beq     icc3,#0,0b      \n"
        : "+U"(v->counter), "=&r"(val)
        : "NPr"(i)
        : "memory", "cc7", "cc3", "icc3"
        );

    return val;
}

static inline int atomic_sub_return(int i, atomic_t *v)
{
    unsigned long val;

    asm("0:                     \n"
        "   orcc        gr0,gr0,gr0,icc3    \n" /* set ICC3.Z */
        "   ckeq        icc3,cc7        \n"
        "   ld.p        %M0,%1          \n" /* LD.P/ORCR must be atomic */
        "   orcr        cc7,cc7,cc3     \n" /* set CC3 to true */
        "   sub%I2      %1,%2,%1        \n"
        "   cst.p       %1,%M0      ,cc3,#1 \n"
        "   corcc       gr29,gr29,gr0   ,cc3,#1 \n" /* clear ICC3.Z if store happens */
        "   beq     icc3,#0,0b      \n"
        : "+U"(v->counter), "=&r"(val)
        : "NPr"(i)
        : "memory", "cc7", "cc3", "icc3"
        );

    return val;
}

#else

extern int atomic_add_return(int i, atomic_t *v);
extern int atomic_sub_return(int i, atomic_t *v);

#endif

static inline int atomic_add_negative(int i, atomic_t *v)
{
    return atomic_add_return(i, v) < 0;
}

static inline void atomic_add(int i, atomic_t *v)
{
    atomic_add_return(i, v);
}

static inline void atomic_sub(int i, atomic_t *v)
{
    atomic_sub_return(i, v);
}

static inline void atomic_inc(atomic_t *v)
{
    atomic_add_return(1, v);
}

static inline void atomic_dec(atomic_t *v)
{
    atomic_sub_return(1, v);
}

#define atomic_dec_return(v)        atomic_sub_return(1, (v))
#define atomic_inc_return(v)        atomic_add_return(1, (v))

#define atomic_sub_and_test(i,v)    (atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v)      (atomic_sub_return(1, (v)) == 0)
#define atomic_inc_and_test(v)      (atomic_add_return(1, (v)) == 0)

/*
 * 64-bit atomic ops
 */
typedef struct {
    volatile long long counter;
} atomic64_t;

#define ATOMIC64_INIT(i)    { (i) }

static inline long long atomic64_read(atomic64_t *v)
{
    long long counter;

    asm("ldd%I1 %M1,%0"
        : "=e"(counter)
        : "m"(v->counter));
    return counter;
}

static inline void atomic64_set(atomic64_t *v, long long i)
{
    asm volatile("std%I0 %1,%M0"
             : "=m"(v->counter)
             : "e"(i));
}

extern long long atomic64_inc_return(atomic64_t *v);
extern long long atomic64_dec_return(atomic64_t *v);
extern long long atomic64_add_return(long long i, atomic64_t *v);
extern long long atomic64_sub_return(long long i, atomic64_t *v);

static inline long long atomic64_add_negative(long long i, atomic64_t *v)
{
    return atomic64_add_return(i, v) < 0;
}

static inline void atomic64_add(long long i, atomic64_t *v)
{
    atomic64_add_return(i, v);
}

static inline void atomic64_sub(long long i, atomic64_t *v)
{
    atomic64_sub_return(i, v);
}

static inline void atomic64_inc(atomic64_t *v)
{
    atomic64_inc_return(v);
}

static inline void atomic64_dec(atomic64_t *v)
{
    atomic64_dec_return(v);
}

#define atomic64_sub_and_test(i,v)  (atomic64_sub_return((i), (v)) == 0)
#define atomic64_dec_and_test(v)    (atomic64_dec_return((v)) == 0)
#define atomic64_inc_and_test(v)    (atomic64_inc_return((v)) == 0)

#define atomic_cmpxchg(v, old, new) (cmpxchg(&(v)->counter, old, new))
#define atomic_xchg(v, new)     (xchg(&(v)->counter, new))
#define atomic64_cmpxchg(v, old, new)   (__cmpxchg_64(old, new, &(v)->counter))
#define atomic64_xchg(v, new)       (__xchg_64(new, &(v)->counter))

static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
{
    int c, old;
    c = atomic_read(v);
    for (;;) {
        if (unlikely(c == (u)))
            break;
        old = atomic_cmpxchg((v), c, c + (a));
        if (likely(old == c))
            break;
        c = old;
    }
    return c;
}


#endif /* _ASM_ATOMIC_H */