atomic.h

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/*
 * Atomic operations for the Hexagon architecture
 *
 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H

#include <linux/types.h>
#include <asm/cmpxchg.h>

#define ATOMIC_INIT(i)      { (i) }
#define atomic_set(v, i)    ((v)->counter = (i))

#define atomic_read(v)      ((v)->counter)

#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))


static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
    int __oldval;

    asm volatile(
        "1: %0 = memw_locked(%1);\n"
        "   { P0 = cmp.eq(%0,%2);\n"
        "     if (!P0.new) jump:nt 2f; }\n"
        "   memw_locked(%1,P0) = %3;\n"
        "   if (!P0) jump 1b;\n"
        "2:\n"
        : "=&r" (__oldval)
        : "r" (&v->counter), "r" (old), "r" (new)
        : "memory", "p0"
    );

    return __oldval;
}

static inline int atomic_add_return(int i, atomic_t *v)
{
    int output;

    __asm__ __volatile__ (
        "1: %0 = memw_locked(%1);\n"
        "   %0 = add(%0,%2);\n"
        "   memw_locked(%1,P3)=%0;\n"
        "   if !P3 jump 1b;\n"
        : "=&r" (output)
        : "r" (&v->counter), "r" (i)
        : "memory", "p3"
    );
    return output;

}

#define atomic_add(i, v) atomic_add_return(i, (v))

static inline int atomic_sub_return(int i, atomic_t *v)
{
    int output;
    __asm__ __volatile__ (
        "1: %0 = memw_locked(%1);\n"
        "   %0 = sub(%0,%2);\n"
        "   memw_locked(%1,P3)=%0\n"
        "   if !P3 jump 1b;\n"
        : "=&r" (output)
        : "r" (&v->counter), "r" (i)
        : "memory", "p3"
    );
    return output;
}

#define atomic_sub(i, v) atomic_sub_return(i, (v))

static inline int __atomic_add_unless(atomic_t *v, int a, int u)
{
    int output, __oldval;
    asm volatile(
        "1: %0 = memw_locked(%2);"
        "   {"
        "       p3 = cmp.eq(%0, %4);"
        "       if (p3.new) jump:nt 2f;"
        "       %0 = add(%0, %3);"
        "       %1 = #0;"
        "   }"
        "   memw_locked(%2, p3) = %0;"
        "   {"
        "       if !p3 jump 1b;"
        "       %1 = #1;"
        "   }"
        "2:"
        : "=&r" (__oldval), "=&r" (output)
        : "r" (v), "r" (a), "r" (u)
        : "memory", "p3"
    );
    return output;
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

#define atomic_inc(v) atomic_add(1, (v))
#define atomic_dec(v) atomic_sub(1, (v))

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


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

#endif