/*-
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013-2018 Mellanox Technologies, Ltd.
 * 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 _LINUXKPI_ASM_ATOMIC_H_
#define _LINUXKPI_ASM_ATOMIC_H_

#include <linux/compiler.h>
#include <sys/types.h>
#include <machine/atomic.h>
#define ATOMIC_INIT(x)  { .counter = (x) }

typedef struct {
        volatile int counter;
} atomic_t;

/*------------------------------------------------------------------------*
 *      32-bit atomic operations
 *------------------------------------------------------------------------*/

#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_add_and_test(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_inc_not_zero(v)          atomic_add_unless((v), 1, 0)

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

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

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

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

static inline void
atomic_set_mask(unsigned int mask, atomic_t *v)
{
        atomic_set_int(&v->counter, mask);
}

static inline int
atomic_read(const atomic_t *v)
{
        return READ_ONCE(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_add_unless(atomic_t *v, int a, int u)
{
        int c = atomic_read(v);

        for (;;) {
                if (unlikely(c == u))
                        break;
                if (likely(atomic_fcmpset_int(&v->counter, &c, c + a)))
                        break;
        }
        return (c != u);
}

static inline int
atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
        int c = atomic_read(v);

        for (;;) {
                if (unlikely(c == u))
                        break;
                if (likely(atomic_fcmpset_int(&v->counter, &c, c + a)))
                        break;
        }
        return (c);
}

static inline void
atomic_clear_mask(unsigned int mask, atomic_t *v)
{
        atomic_clear_int(&v->counter, mask);
}

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

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

        for (;;) {
                if (atomic_fcmpset_int(&v->counter, &ret, new))
                        break;
                if (ret != old)
                        break;
        }
        return (ret);
}

#if defined(__amd64__) || defined(__arm64__) || defined(__i386__)
#define LINUXKPI_ATOMIC_8(...) __VA_ARGS__
#define LINUXKPI_ATOMIC_16(...) __VA_ARGS__
#else
#define LINUXKPI_ATOMIC_8(...)
#define LINUXKPI_ATOMIC_16(...)
#endif

#if !(defined(i386) || (defined(__powerpc__) && !defined(__powerpc64__)))
#define LINUXKPI_ATOMIC_64(...) __VA_ARGS__
#else
#define LINUXKPI_ATOMIC_64(...)
#endif

#define cmpxchg(ptr, old, new) ({                                       \
        union {                                                         \
                __typeof(*(ptr)) val;                                   \
                u8 u8[0];                                               \
                u16 u16[0];                                             \
                u32 u32[0];                                             \
                u64 u64[0];                                             \
        } __ret = { .val = (old) }, __new = { .val = (new) };           \
                                                                        \
        CTASSERT(                                                       \
            LINUXKPI_ATOMIC_8(sizeof(__ret.val) == 1 ||)                \
            LINUXKPI_ATOMIC_16(sizeof(__ret.val) == 2 ||)               \
            LINUXKPI_ATOMIC_64(sizeof(__ret.val) == 8 ||)               \
            sizeof(__ret.val) == 4);                                    \
                                                                        \
        switch (sizeof(__ret.val)) {                                    \
        LINUXKPI_ATOMIC_8(                                              \
        case 1:                                                         \
                while (!atomic_fcmpset_8((volatile u8 *)(ptr),          \
                    __ret.u8, __new.u8[0]) && __ret.val == (old))       \
                        ;                                               \
                break;                                                  \
        )                                                               \
        LINUXKPI_ATOMIC_16(                                             \
        case 2:                                                         \
                while (!atomic_fcmpset_16((volatile u16 *)(ptr),        \
                    __ret.u16, __new.u16[0]) && __ret.val == (old))     \
                        ;                                               \
                break;                                                  \
        )                                                               \
        case 4:                                                         \
                while (!atomic_fcmpset_32((volatile u32 *)(ptr),        \
                    __ret.u32, __new.u32[0]) && __ret.val == (old))     \
                        ;                                               \
                break;                                                  \
        LINUXKPI_ATOMIC_64(                                             \
        case 8:                                                         \
                while (!atomic_fcmpset_64((volatile u64 *)(ptr),        \
                    __ret.u64, __new.u64[0]) && __ret.val == (old))     \
                        ;                                               \
                break;                                                  \
        )                                                               \
        }                                                               \
        __ret.val;                                                      \
})

#define cmpxchg64(...)          cmpxchg(__VA_ARGS__)
#define cmpxchg_relaxed(...)    cmpxchg(__VA_ARGS__)

#define xchg(ptr, new) ({                                               \
        union {                                                         \
                __typeof(*(ptr)) val;                                   \
                u8 u8[0];                                               \
                u16 u16[0];                                             \
                u32 u32[0];                                             \
                u64 u64[0];                                             \
        } __ret, __new = { .val = (new) };                              \
                                                                        \
        CTASSERT(                                                       \
            LINUXKPI_ATOMIC_8(sizeof(__ret.val) == 1 ||)                \
            LINUXKPI_ATOMIC_16(sizeof(__ret.val) == 2 ||)               \
            LINUXKPI_ATOMIC_64(sizeof(__ret.val) == 8 ||)               \
            sizeof(__ret.val) == 4);                                    \
                                                                        \
        switch (sizeof(__ret.val)) {                                    \
        LINUXKPI_ATOMIC_8(                                              \
        case 1:                                                         \
                __ret.val = READ_ONCE(*ptr);                            \
                while (!atomic_fcmpset_8((volatile u8 *)(ptr),          \
                    __ret.u8, __new.u8[0]))                             \
                        ;                                               \
                break;                                                  \
        )                                                               \
        LINUXKPI_ATOMIC_16(                                             \
        case 2:                                                         \
                __ret.val = READ_ONCE(*ptr);                            \
                while (!atomic_fcmpset_16((volatile u16 *)(ptr),        \
                    __ret.u16, __new.u16[0]))                           \
                        ;                                               \
                break;                                                  \
        )                                                               \
        case 4:                                                         \
                __ret.u32[0] = atomic_swap_32((volatile u32 *)(ptr),    \
                    __new.u32[0]);                                      \
                break;                                                  \
        LINUXKPI_ATOMIC_64(                                             \
        case 8:                                                         \
                __ret.u64[0] = atomic_swap_64((volatile u64 *)(ptr),    \
                    __new.u64[0]);                                      \
                break;                                                  \
        )                                                               \
        }                                                               \
        __ret.val;                                                      \
})

#define try_cmpxchg(p, op, n)                                                   \
({                                                                              \
        __typeof(p) __op = (__typeof((p)))(op);                                 \
        __typeof(*(p)) __o = *__op;                                             \
        __typeof(*(p)) __p = __sync_val_compare_and_swap((p), (__o), (n));      \
        if (__p != __o)                                                         \
                *__op = __p;                                                    \
        (__p == __o);                                                           \
})

#define __atomic_try_cmpxchg(type, _p, _po, _n)         \
({                                                      \
        __typeof(_po) __po = (_po);                     \
        __typeof(*(_po)) __r, __o = *__po;              \
        __r = atomic_cmpxchg##type((_p), __o, (_n));    \
        if (unlikely(__r != __o))                       \
                *__po = __r;                            \
        likely(__r == __o);                             \
})

#define atomic_try_cmpxchg(_p, _po, _n) __atomic_try_cmpxchg(, _p, _po, _n)

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);
}

#define LINUX_ATOMIC_OP(op, c_op)                               \
static inline void atomic_##op(int i, atomic_t *v)              \
{                                                               \
        int c, old;                                             \
                                                                \
        c = v->counter;                                         \
        while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)     \
                c = old;                                        \
}

#define LINUX_ATOMIC_FETCH_OP(op, c_op)                         \
static inline int atomic_fetch_##op(int i, atomic_t *v)         \
{                                                               \
        int c, old;                                             \
                                                                \
        c = v->counter;                                         \
        while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)     \
                c = old;                                        \
                                                                \
        return (c);                                             \
}

static inline int
atomic_fetch_inc(atomic_t *v)
{

        return ((atomic_inc_return(v) - 1));
}

LINUX_ATOMIC_OP(or, |)
LINUX_ATOMIC_OP(and, &)
LINUX_ATOMIC_OP(andnot, &~)
LINUX_ATOMIC_OP(xor, ^)

LINUX_ATOMIC_FETCH_OP(or, |)
LINUX_ATOMIC_FETCH_OP(and, &)
LINUX_ATOMIC_FETCH_OP(andnot, &~)
LINUX_ATOMIC_FETCH_OP(xor, ^)

#endif                                  /* _LINUXKPI_ASM_ATOMIC_H_ */