atomic.h

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#ifndef __ARCH_M68K_ATOMIC__
#define __ARCH_M68K_ATOMIC__

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

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

/*
 * We do not have SMP m68k systems, so we don't have to deal with that.
 */

#define ATOMIC_INIT(i)  { (i) }

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

/*
 * The ColdFire parts cannot do some immediate to memory operations,
 * so for them we do not specify the "i" asm constraint.
 */
#ifdef CONFIG_COLDFIRE
#define ASM_DI  "d"
#else
#define ASM_DI  "di"
#endif

static inline void atomic_add(int i, atomic_t *v)
{
    __asm__ __volatile__("addl %1,%0" : "+m" (*v) : ASM_DI (i));
}

static inline void atomic_sub(int i, atomic_t *v)
{
    __asm__ __volatile__("subl %1,%0" : "+m" (*v) : ASM_DI (i));
}

static inline void atomic_inc(atomic_t *v)
{
    __asm__ __volatile__("addql #1,%0" : "+m" (*v));
}

static inline void atomic_dec(atomic_t *v)
{
    __asm__ __volatile__("subql #1,%0" : "+m" (*v));
}

static inline int atomic_dec_and_test(atomic_t *v)
{
    char c;
    __asm__ __volatile__("subql #1,%1; seq %0" : "=d" (c), "+m" (*v));
    return c != 0;
}

static inline int atomic_dec_and_test_lt(atomic_t *v)
{
    char c;
    __asm__ __volatile__(
        "subql #1,%1; slt %0"
        : "=d" (c), "=m" (*v)
        : "m" (*v));
    return c != 0;
}

static inline int atomic_inc_and_test(atomic_t *v)
{
    char c;
    __asm__ __volatile__("addql #1,%1; seq %0" : "=d" (c), "+m" (*v));
    return c != 0;
}

#ifdef CONFIG_RMW_INSNS

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

    __asm__ __volatile__(
            "1: movel %2,%1\n"
            "   addl %3,%1\n"
            "   casl %2,%1,%0\n"
            "   jne 1b"
            : "+m" (*v), "=&d" (t), "=&d" (tmp)
            : "g" (i), "2" (atomic_read(v)));
    return t;
}

static inline int atomic_sub_return(int i, atomic_t *v)
{
    int t, tmp;

    __asm__ __volatile__(
            "1: movel %2,%1\n"
            "   subl %3,%1\n"
            "   casl %2,%1,%0\n"
            "   jne 1b"
            : "+m" (*v), "=&d" (t), "=&d" (tmp)
            : "g" (i), "2" (atomic_read(v)));
    return t;
}

#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

#else /* !CONFIG_RMW_INSNS */

static inline int atomic_add_return(int i, atomic_t * v)
{
    unsigned long flags;
    int t;

    local_irq_save(flags);
    t = atomic_read(v);
    t += i;
    atomic_set(v, t);
    local_irq_restore(flags);

    return t;
}

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

    local_irq_save(flags);
    t = atomic_read(v);
    t -= i;
    atomic_set(v, t);
    local_irq_restore(flags);

    return t;
}

static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
    unsigned long flags;
    int prev;

    local_irq_save(flags);
    prev = atomic_read(v);
    if (prev == old)
        atomic_set(v, new);
    local_irq_restore(flags);
    return prev;
}

static inline int atomic_xchg(atomic_t *v, int new)
{
    unsigned long flags;
    int prev;

    local_irq_save(flags);
    prev = atomic_read(v);
    atomic_set(v, new);
    local_irq_restore(flags);
    return prev;
}

#endif /* !CONFIG_RMW_INSNS */

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

static inline int atomic_sub_and_test(int i, atomic_t *v)
{
    char c;
    __asm__ __volatile__("subl %2,%1; seq %0"
                 : "=d" (c), "+m" (*v)
                 : ASM_DI (i));
    return c != 0;
}

static inline int atomic_add_negative(int i, atomic_t *v)
{
    char c;
    __asm__ __volatile__("addl %2,%1; smi %0"
                 : "=d" (c), "+m" (*v)
                 : ASM_DI (i));
    return c != 0;
}

static inline void atomic_clear_mask(unsigned long mask, unsigned long *v)
{
    __asm__ __volatile__("andl %1,%0" : "+m" (*v) : ASM_DI (~(mask)));
}

static inline void atomic_set_mask(unsigned long mask, unsigned long *v)
{
    __asm__ __volatile__("orl %1,%0" : "+m" (*v) : ASM_DI (mask));
}

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;
}


/* 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()

#endif /* __ARCH_M68K_ATOMIC __ */