/*
 *  arch/arm/include/asm/atomic.h
 *
 *  Copyright (C) 1996 Russell King.
 *  Copyright (C) 2002 Deep Blue Solutions Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef __ASM_ARM_ATOMIC_H
#define __ASM_ARM_ATOMIC_H

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

#define ATOMIC_INIT(i)  { (i) }

#ifdef __KERNEL__

/*
 * On ARM, ordinary assignment (str instruction) doesn't clear the local
 * strex/ldrex monitor on some implementations. The reason we can use it for
 * atomic_set() is the clrex or dummy strex done on every exception return.
 */
#define atomic_read(v)  ACCESS_ONCE((v)->counter)
#define atomic_set(v,i) (((v)->counter) = (i))

#if __LINUX_ARM_ARCH__ >= 6

/*
 * ARMv6 UP and SMP safe atomic ops.  We use load exclusive and
 * store exclusive to ensure that these are atomic.  We may loop
 * to ensure that the update happens.
 */
static inline void atomic_add(int i, atomic_t *v)
{
        unsigned long tmp;
        int result;

        __asm__ __volatile__("@ atomic_add\n"
"1:     ldrex   %0, [%3]\n"
"       add     %0, %0, %4\n"
"       strex   %1, %0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "Ir" (i)
        : "cc");
}

static inline int atomic_add_return(int i, atomic_t *v)
{
        unsigned long tmp;
        int result;

        smp_mb();

        __asm__ __volatile__("@ atomic_add_return\n"
"1:     ldrex   %0, [%3]\n"
"       add     %0, %0, %4\n"
"       strex   %1, %0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "Ir" (i)
        : "cc");

        smp_mb();

        return result;
}

static inline void atomic_sub(int i, atomic_t *v)
{
        unsigned long tmp;
        int result;

        __asm__ __volatile__("@ atomic_sub\n"
"1:     ldrex   %0, [%3]\n"
"       sub     %0, %0, %4\n"
"       strex   %1, %0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "Ir" (i)
        : "cc");
}

static inline int atomic_sub_return(int i, atomic_t *v)
{
        unsigned long tmp;
        int result;

        smp_mb();

        __asm__ __volatile__("@ atomic_sub_return\n"
"1:     ldrex   %0, [%3]\n"
"       sub     %0, %0, %4\n"
"       strex   %1, %0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "Ir" (i)
        : "cc");

        smp_mb();

        return result;
}

static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
{
        unsigned long oldval, res;

        smp_mb();

        do {
                __asm__ __volatile__("@ atomic_cmpxchg\n"
                "ldrex  %1, [%3]\n"
                "mov    %0, #0\n"
                "teq    %1, %4\n"
                "strexeq %0, %5, [%3]\n"
                    : "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
                    : "r" (&ptr->counter), "Ir" (old), "r" (new)
                    : "cc");
        } while (res);

        smp_mb();

        return oldval;
}

static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
{
        unsigned long tmp, tmp2;

        __asm__ __volatile__("@ atomic_clear_mask\n"
"1:     ldrex   %0, [%3]\n"
"       bic     %0, %0, %4\n"
"       strex   %1, %0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (tmp), "=&r" (tmp2), "+Qo" (*addr)
        : "r" (addr), "Ir" (mask)
        : "cc");
}

#else /* ARM_ARCH_6 */

#ifdef CONFIG_SMP
#error SMP not supported on pre-ARMv6 CPUs
#endif

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

        raw_local_irq_save(flags);
        val = v->counter;
        v->counter = val += i;
        raw_local_irq_restore(flags);

        return val;
}
#define atomic_add(i, v)        (void) atomic_add_return(i, v)

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

        raw_local_irq_save(flags);
        val = v->counter;
        v->counter = val -= i;
        raw_local_irq_restore(flags);

        return val;
}
#define atomic_sub(i, v)        (void) atomic_sub_return(i, v)

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

        raw_local_irq_save(flags);
        ret = v->counter;
        if (likely(ret == old))
                v->counter = new;
        raw_local_irq_restore(flags);

        return ret;
}

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

        raw_local_irq_save(flags);
        *addr &= ~mask;
        raw_local_irq_restore(flags);
}

#endif /* __LINUX_ARM_ARCH__ */

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

static inline int __atomic_add_unless(atomic_t *v, int a, int u)
{
        int c, old;

        c = atomic_read(v);
        while (c != u && (old = atomic_cmpxchg((v), c, c + a)) != c)
                c = old;
        return c;
}

#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_inc_return(v)    (atomic_add_return(1, v))
#define atomic_dec_return(v)    (atomic_sub_return(1, v))
#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 smp_mb__before_atomic_dec()     smp_mb()
#define smp_mb__after_atomic_dec()      smp_mb()
#define smp_mb__before_atomic_inc()     smp_mb()
#define smp_mb__after_atomic_inc()      smp_mb()

#ifndef CONFIG_GENERIC_ATOMIC64
typedef struct {
        u64 __aligned(8) counter;
} atomic64_t;

#define ATOMIC64_INIT(i) { (i) }

#ifdef CONFIG_ARM_LPAE
static inline u64 atomic64_read(const atomic64_t *v)
{
        u64 result;

        __asm__ __volatile__("@ atomic64_read\n"
"       ldrd    %0, %H0, [%1]"
        : "=&r" (result)
        : "r" (&v->counter), "Qo" (v->counter)
        );

        return result;
}

static inline void atomic64_set(atomic64_t *v, u64 i)
{
        __asm__ __volatile__("@ atomic64_set\n"
"       strd    %2, %H2, [%1]"
        : "=Qo" (v->counter)
        : "r" (&v->counter), "r" (i)
        );
}
#else
static inline u64 atomic64_read(const atomic64_t *v)
{
        u64 result;

        __asm__ __volatile__("@ atomic64_read\n"
"       ldrexd  %0, %H0, [%1]"
        : "=&r" (result)
        : "r" (&v->counter), "Qo" (v->counter)
        );

        return result;
}

static inline void atomic64_set(atomic64_t *v, u64 i)
{
        u64 tmp;

        __asm__ __volatile__("@ atomic64_set\n"
"1:     ldrexd  %0, %H0, [%2]\n"
"       strexd  %0, %3, %H3, [%2]\n"
"       teq     %0, #0\n"
"       bne     1b"
        : "=&r" (tmp), "=Qo" (v->counter)
        : "r" (&v->counter), "r" (i)
        : "cc");
}
#endif

static inline void atomic64_add(u64 i, atomic64_t *v)
{
        u64 result;
        unsigned long tmp;

        __asm__ __volatile__("@ atomic64_add\n"
"1:     ldrexd  %0, %H0, [%3]\n"
"       adds    %0, %0, %4\n"
"       adc     %H0, %H0, %H4\n"
"       strexd  %1, %0, %H0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "r" (i)
        : "cc");
}

static inline u64 atomic64_add_return(u64 i, atomic64_t *v)
{
        u64 result;
        unsigned long tmp;

        smp_mb();

        __asm__ __volatile__("@ atomic64_add_return\n"
"1:     ldrexd  %0, %H0, [%3]\n"
"       adds    %0, %0, %4\n"
"       adc     %H0, %H0, %H4\n"
"       strexd  %1, %0, %H0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "r" (i)
        : "cc");

        smp_mb();

        return result;
}

static inline void atomic64_sub(u64 i, atomic64_t *v)
{
        u64 result;
        unsigned long tmp;

        __asm__ __volatile__("@ atomic64_sub\n"
"1:     ldrexd  %0, %H0, [%3]\n"
"       subs    %0, %0, %4\n"
"       sbc     %H0, %H0, %H4\n"
"       strexd  %1, %0, %H0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "r" (i)
        : "cc");
}

static inline u64 atomic64_sub_return(u64 i, atomic64_t *v)
{
        u64 result;
        unsigned long tmp;

        smp_mb();

        __asm__ __volatile__("@ atomic64_sub_return\n"
"1:     ldrexd  %0, %H0, [%3]\n"
"       subs    %0, %0, %4\n"
"       sbc     %H0, %H0, %H4\n"
"       strexd  %1, %0, %H0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "r" (i)
        : "cc");

        smp_mb();

        return result;
}

static inline u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old, u64 new)
{
        u64 oldval;
        unsigned long res;

        smp_mb();

        do {
                __asm__ __volatile__("@ atomic64_cmpxchg\n"
                "ldrexd         %1, %H1, [%3]\n"
                "mov            %0, #0\n"
                "teq            %1, %4\n"
                "teqeq          %H1, %H4\n"
                "strexdeq       %0, %5, %H5, [%3]"
                : "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
                : "r" (&ptr->counter), "r" (old), "r" (new)
                : "cc");
        } while (res);

        smp_mb();

        return oldval;
}

static inline u64 atomic64_xchg(atomic64_t *ptr, u64 new)
{
        u64 result;
        unsigned long tmp;

        smp_mb();

        __asm__ __volatile__("@ atomic64_xchg\n"
"1:     ldrexd  %0, %H0, [%3]\n"
"       strexd  %1, %4, %H4, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b"
        : "=&r" (result), "=&r" (tmp), "+Qo" (ptr->counter)
        : "r" (&ptr->counter), "r" (new)
        : "cc");

        smp_mb();

        return result;
}

static inline u64 atomic64_dec_if_positive(atomic64_t *v)
{
        u64 result;
        unsigned long tmp;

        smp_mb();

        __asm__ __volatile__("@ atomic64_dec_if_positive\n"
"1:     ldrexd  %0, %H0, [%3]\n"
"       subs    %0, %0, #1\n"
"       sbc     %H0, %H0, #0\n"
"       teq     %H0, #0\n"
"       bmi     2f\n"
"       strexd  %1, %0, %H0, [%3]\n"
"       teq     %1, #0\n"
"       bne     1b\n"
"2:"
        : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter)
        : "cc");

        smp_mb();

        return result;
}

static inline int atomic64_add_unless(atomic64_t *v, u64 a, u64 u)
{
        u64 val;
        unsigned long tmp;
        int ret = 1;

        smp_mb();

        __asm__ __volatile__("@ atomic64_add_unless\n"
"1:     ldrexd  %0, %H0, [%4]\n"
"       teq     %0, %5\n"
"       teqeq   %H0, %H5\n"
"       moveq   %1, #0\n"
"       beq     2f\n"
"       adds    %0, %0, %6\n"
"       adc     %H0, %H0, %H6\n"
"       strexd  %2, %0, %H0, [%4]\n"
"       teq     %2, #0\n"
"       bne     1b\n"
"2:"
        : "=&r" (val), "+r" (ret), "=&r" (tmp), "+Qo" (v->counter)
        : "r" (&v->counter), "r" (u), "r" (a)
        : "cc");

        if (ret)
                smp_mb();

        return ret;
}

#define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
#define atomic64_inc(v)                 atomic64_add(1LL, (v))
#define atomic64_inc_return(v)          atomic64_add_return(1LL, (v))
#define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
#define atomic64_sub_and_test(a, v)     (atomic64_sub_return((a), (v)) == 0)
#define atomic64_dec(v)                 atomic64_sub(1LL, (v))
#define atomic64_dec_return(v)          atomic64_sub_return(1LL, (v))
#define atomic64_dec_and_test(v)        (atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v)        atomic64_add_unless((v), 1LL, 0LL)

#endif /* !CONFIG_GENERIC_ATOMIC64 */
#endif
#endif