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- /*
- * 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);
- }
- }
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