/*-
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
 * Copyright (c) 2013-2020 François Tigeot <ftigeot@wolfpond.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _LINUX_ATOMIC_H_
#define _LINUX_ATOMIC_H_

#include <asm/atomic.h>
#include <asm/barrier.h>

typedef struct {
        volatile u_int counter;
} atomic_t;

#define atomic_add(i, v)                atomic_add_return((i), (v))
#define atomic_sub(i, v)                atomic_sub_return((i), (v))
#define atomic_inc_return(v)            atomic_add_return(1, (v))
#define atomic_add_negative(i, v)       (atomic_add_return((i), (v)) < 0)
#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_dec_return(v)             atomic_sub_return(1, (v))
#define atomic_fetch_inc(v)             (atomic_inc_return(v) - 1)

#define atomic64_add(i, v)              atomic_add_return_long((i), (v))
#define atomic64_sub(i, v)              atomic_sub_return_long((i), (v))

#define atomic_xchg(p, v)               atomic_swap_int(&((p)->counter), v)
#define atomic64_xchg(p, v)             atomic_swap_long(&((p)->counter), v)

#define atomic_cmpset(p, o, n)          atomic_cmpset_32(&((p)->counter), o, n)

#define atomic64_cmpxchg(p, o, n)                                               \
        (atomic_cmpset_long((volatile uint64_t *)(p),(o),(n)) ? (o) : (0))

static inline int
atomic_add_return(int i, atomic_t *v)
{
        return i + atomic_fetchadd_int(&v->counter, i);
}

static inline int64_t
atomic_add_return_long(int64_t i, atomic64_t *v)
{
        return i + atomic_fetchadd_long(&v->counter, i);
}

static inline int
atomic_sub_return(int i, atomic_t *v)
{
        return atomic_fetchadd_int(&v->counter, -i) - i;
}

static inline int64_t
atomic_sub_return_long(int64_t i, atomic64_t *v)
{
        return atomic_fetchadd_long(&v->counter, -i) - i;
}

static inline void
atomic_set(atomic_t *v, int i)
{
        atomic_store_rel_int(&v->counter, i);
}

static inline void
atomic64_set(atomic64_t *v, long i)
{
        atomic_store_rel_long(&v->counter, i);
}

static inline int
atomic_read(const atomic_t *v)
{
        return READ_ONCE(v->counter);
}

static inline int64_t
atomic64_read(atomic64_t *v)
{
        return atomic_load_acq_long(&v->counter);
}

static inline int
atomic_inc(atomic_t *v)
{
        return atomic_fetchadd_int(&v->counter, 1) + 1;
}

static inline int
atomic_dec(atomic_t *v)
{
        return atomic_fetchadd_int(&v->counter, -1) - 1;
}

static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
        return atomic_cmpxchg_int(&v->counter, old, new);
}

static inline int atomic_add_unless(atomic_t *v, int add, int unless)
{
        int c, old;
        c = atomic_read(v);
        for (;;) {
                if (unlikely(c == unless))
                        break;
                old = atomic_cmpxchg_int(&v->counter, c, c + add);
                if (likely(old == c))
                        break;
                c = old;
        }
        return c != unless;
}

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

/* atomic_clear_mask: atomically clears a variable from the bit set in mask */
#define atomic_clear_mask(mask, addr)           \
        /* atomic *addr &= ~mask; */            \
        __asm __volatile("lock andl %0, %1"     \
                :                               \
                : "r" (~mask), "m" (*addr)      \
                : "memory");

#define smp_mb__before_atomic() cpu_ccfence()
#define smp_mb__after_atomic()  cpu_ccfence()

static inline void
atomic_andnot(int i, atomic_t *v)
{
        /* v->counter = v->counter & ~i; */
        atomic_clear_int(&v->counter, i);
}

#define cmpxchg(ptr, old, new) ({                                       \
        __typeof(*(ptr)) __ret;                                         \
                                                                        \
        CTASSERT(sizeof(__ret) == 1 || sizeof(__ret) == 2 ||            \
            sizeof(__ret) == 4 || sizeof(__ret) == 8);                  \
                                                                        \
        __ret = (old);                                                  \
        switch (sizeof(__ret)) {                                        \
        case 1:                                                         \
                while (!atomic_fcmpset_8((volatile int8_t *)(ptr),      \
                    (int8_t *)&__ret, (u64)(new)) && __ret == (old))    \
                        ;                                               \
                break;                                                  \
        case 2:                                                         \
                while (!atomic_fcmpset_16((volatile int16_t *)(ptr),    \
                    (int16_t *)&__ret, (u64)(new)) && __ret == (old))   \
                        ;                                               \
                break;                                                  \
        case 4:                                                         \
                while (!atomic_fcmpset_32((volatile int32_t *)(ptr),    \
                    (int32_t *)&__ret, (u64)(new)) && __ret == (old))   \
                        ;                                               \
                break;                                                  \
        case 8:                                                         \
                while (!atomic_fcmpset_64((volatile int64_t *)(ptr),    \
                    (int64_t *)&__ret, (u64)(new)) && __ret == (old))   \
                        ;                                               \
                break;                                                  \
        }                                                               \
        __ret;                                                          \
})

#define cmpxchg_relaxed(...)    cmpxchg(__VA_ARGS__)

#define atomic64_inc_return(p)  __sync_add_and_fetch_8(p, 1)

static inline void
atomic_set_release(atomic_t *v, int i)
{
        atomic_store_rel_int(&v->counter, i);
}

/* Returns the old value of v->counter */
static inline int
atomic_fetch_xor(int i, atomic_t *v)
{
        int val = READ_ONCE(v->counter);

        while (atomic_cmpxchg_int(&v->counter, val, val ^ i) == 0) {
        }

        return val;
}

static inline int
atomic_dec_if_positive(atomic_t *v)
{
        int retval;
        int old;

        old = atomic_read(v);
        for (;;) {
                retval = old - 1;
                if (unlikely(retval < 0))
                        break;
                if (likely(atomic_fcmpset_int(&v->counter, &old, retval)))
                        break;
        }
        return (retval);
}

#include <asm-generic/atomic-long.h>

#endif  /* _LINUX_ATOMIC_H_ */