root/include/asm-mn10300/atomic.h

INCLUDED FROM

DEFINITIONS

1. atomic_add_return
2. atomic_sub_return
3. atomic_add_negative
4. atomic_add
5. atomic_sub
6. atomic_inc
7. atomic_dec
8. atomic_clear_mask

/* MN10300 Atomic counter operations
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H

#ifdef CONFIG_SMP
#error not SMP safe
#endif

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

/*
 * Make sure gcc doesn't try to be clever and move things around
 * on us. We need to use _exactly_ the address the user gave us,
 * not some alias that contains the same information.
 */
typedef struct {
        int     counter;
} atomic_t;

#define ATOMIC_INIT(i)  { (i) }

#ifdef __KERNEL__

/**
 * atomic_read - read atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically reads the value of @v.  Note that the guaranteed
 * useful range of an atomic_t is only 24 bits.
 */
#define atomic_read(v)  ((v)->counter)

/**
 * atomic_set - set atomic variable
 * @v: pointer of type atomic_t
 * @i: required value
 *
 * Atomically sets the value of @v to @i.  Note that the guaranteed
 * useful range of an atomic_t is only 24 bits.
 */
#define atomic_set(v, i) (((v)->counter) = (i))

#include <asm/system.h>

/**
 * atomic_add_return - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic_t
 *
 * Atomically adds @i to @v and returns the result
 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
 */
static inline int atomic_add_return(int i, atomic_t *v)
{
        unsigned long flags;
        int temp;

        local_irq_save(flags);
        temp = v->counter;
        temp += i;
        v->counter = temp;
        local_irq_restore(flags);

        return temp;
}

/**
 * atomic_sub_return - subtract integer from atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v and returns the result
 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
 */
static inline int atomic_sub_return(int i, atomic_t *v)
{
        unsigned long flags;
        int temp;

        local_irq_save(flags);
        temp = v->counter;
        temp -= i;
        v->counter = temp;
        local_irq_restore(flags);

        return temp;
}

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)

#define atomic_add_unless(v, a, u)                              \
({                                                              \
        int c, old;                                             \
        c = atomic_read(v);                                     \
        while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
                c = old;                                        \
        c != (u);                                               \
})

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

static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
{
        unsigned long flags;

        mask = ~mask;
        local_irq_save(flags);
        *addr &= mask;
        local_irq_restore(flags);
}

#define atomic_xchg(ptr, v)             (xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new)     (cmpxchg(&((v)->counter), (old), (new)))

/* Atomic operations are already serializing on MN10300??? */
#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()

#include <asm-generic/atomic.h>

#endif /* __KERNEL__ */
#endif /* _ASM_ATOMIC_H */