/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 *
 * But use these as seldom as possible since they are much more slower
 * than regular operations.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1996, 97, 99, 2000, 03, 04, 06 by Ralf Baechle
 */
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H

#include <linux/irqflags.h>
#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/cpu-features.h>
#include <asm/cmpxchg.h>
#include <asm/war.h>

#define ATOMIC_INIT(i)    { (i) }

/*
 * atomic_read - read atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically reads the value of @v.
 */
#define atomic_read(v)		(*(volatile int *)&(v)->counter)

/*
 * atomic_set - set atomic variable
 * @v: pointer of type atomic_t
 * @i: required value
 *
 * Atomically sets the value of @v to @i.
 */
#define atomic_set(v, i)		((v)->counter = (i))

/*
 * atomic_add - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic_t
 *
 * Atomically adds @i to @v.
 */
static __inline__ void atomic_add(int i, atomic_t * v)
{
	if (kernel_uses_llsc && R10000_LLSC_WAR) {
		int temp;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	ll	%0, %1		# atomic_add		\n"
		"	addu	%0, %2					\n"
		"	sc	%0, %1					\n"
		"	beqzl	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "+m" (v->counter)
		: "Ir" (i));
	} else if (kernel_uses_llsc) {
		int temp;

		do {
			__asm__ __volatile__(
			"	.set	mips3				\n"
			"	ll	%0, %1		# atomic_add	\n"
			"	addu	%0, %2				\n"
			"	sc	%0, %1				\n"
			"	.set	mips0				\n"
			: "=&r" (temp), "+m" (v->counter)
			: "Ir" (i));
		} while (unlikely(!temp));
	} else {
		unsigned long flags;

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

/*
 * atomic_sub - subtract the atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v.
 */
static __inline__ void atomic_sub(int i, atomic_t * v)
{
	if (kernel_uses_llsc && R10000_LLSC_WAR) {
		int temp;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	ll	%0, %1		# atomic_sub		\n"
		"	subu	%0, %2					\n"
		"	sc	%0, %1					\n"
		"	beqzl	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "+m" (v->counter)
		: "Ir" (i));
	} else if (kernel_uses_llsc) {
		int temp;

		do {
			__asm__ __volatile__(
			"	.set	mips3				\n"
			"	ll	%0, %1		# atomic_sub	\n"
			"	subu	%0, %2				\n"
			"	sc	%0, %1				\n"
			"	.set	mips0				\n"
			: "=&r" (temp), "+m" (v->counter)
			: "Ir" (i));
		} while (unlikely(!temp));
	} else {
		unsigned long flags;

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