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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 <linux/linkage.h>
#include <asm/barrier.h>
#include <asm/cpu-features.h>
#include <asm/system.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) ((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)
{
#ifdef CONFIG_CPU_HAS_LLSC
int temp;
smp_llsc_mb();
__asm__ __volatile__(
" .set mips3 \n"
"1: ll %0, %1 # atomic_add \n"
#if defined(CONFIG_CPU_RLX4181) || defined(CONFIG_CPU_RLX5181) || defined(CONFIG_CPU_RLX5281)
" nop \n"
#endif
" addu %0, %2 \n"
" sc %0, %1 \n"
" beqz %0, 2f \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
" .set mips0 \n"
: "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter));
smp_llsc_mb();
#else
unsigned long flags;
raw_local_irq_save(flags);
v->counter += i;
raw_local_irq_restore(flags);
#endif
}
/*
* 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)
{
#ifdef CONFIG_CPU_HAS_LLSC
int temp;
smp_llsc_mb();
__asm__ __volatile__(
"1: ll %0, %1 # atomic_sub \n"
#if defined(CONFIG_CPU_RLX4181) || defined(CONFIG_CPU_RLX5181) || defined(CONFIG_CPU_RLX5281)
" nop \n"
#endif
" subu %0, %2 \n"
" sc %0, %1 \n"
" beqz %0, 2f \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
: "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter));
smp_llsc_mb();
#else
unsigned long flags;
raw_local_irq_save(flags);
v->counter -= i;
raw_local_irq_restore(flags);
#endif
}
/*
* Same as above, but return the result value
*/
static __inline__ int atomic_add_return(int i, atomic_t * v)
{
#ifdef CONFIG_CPU_HAS_LLSC
int result;
int temp;
smp_llsc_mb();
__asm__ __volatile__(
"1: ll %1, %2 # atomic_add_return \n"
#if defined(CONFIG_CPU_RLX4181) || defined(CONFIG_CPU_RLX5181) || defined(CONFIG_CPU_RLX5281)
" nop \n"
#endif
" addu %0, %1, %3 \n"
" sc %0, %2 \n"
" beqz %0, 2f \n"
" addu %0, %1, %3 \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)
: "memory");
smp_llsc_mb();
#else
int result;
unsigned long flags;
raw_local_irq_save(flags);
result = v->counter;
result += i;
v->counter = result;
raw_local_irq_restore(flags);
#endif
return result;
}
static __inline__ int atomic_sub_return(int i, atomic_t * v)
{
#ifdef CONFIG_CPU_HAS_LLSC
int result;
int temp;
smp_llsc_mb();
__asm__ __volatile__(
"1: ll %1, %2 # atomic_sub_return \n"
#if defined(CONFIG_CPU_RLX4181) || defined(CONFIG_CPU_RLX5181) || defined(CONFIG_CPU_RLX5281)
" nop \n"
#endif
" subu %0, %1, %3 \n"
" sc %0, %2 \n"
" beqz %0, 2f \n"
" subu %0, %1, %3 \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)
: "memory");
smp_llsc_mb();
#else
unsigned long flags;
int result;
raw_local_irq_save(flags);
result = v->counter;
result -= i;
v->counter = result;
raw_local_irq_restore(flags);
#endif
return result;
}
/*
* atomic_sub_if_positive - conditionally subtract integer from atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically test @v and subtract @i if @v is greater or equal than @i.
* The function returns the old value of @v minus @i.
*/
static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
{
#ifdef CONFIG_CPU_HAS_LLSC
int result;
int temp;
smp_llsc_mb();
__asm__ __volatile__(
"1: ll %1, %2 # atomic_sub_if_positive\n"
#if defined(CONFIG_CPU_RLX4181) || defined(CONFIG_CPU_RLX5181) || defined(CONFIG_CPU_RLX5281)
" nop \n"
#endif
" subu %0, %1, %3 \n"
" bltz %0, 1f \n"
" sc %0, %2 \n"
" .set noreorder \n"
" beqz %0, 2f \n"
" subu %0, %1, %3 \n"
" .set reorder \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
"1: \n"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)
: "memory");
smp_llsc_mb();
#else
unsigned long flags;
int result;
raw_local_irq_save(flags);
result = v->counter;
result -= i;
if (result >= 0)
v->counter = result;
raw_local_irq_restore(flags);
#endif
return result;
}
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
/**
* atomic_add_unless - add unless the number is a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as it was not @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c != (u);
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
#define atomic_dec_return(v) atomic_sub_return(1, (v))
#define atomic_inc_return(v) atomic_add_return(1, (v))
/*
* atomic_sub_and_test - subtract value from variable and test result
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v and returns
* true if the result is zero, or false for all
* other cases.
*/
#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
/*
* atomic_dec_and_test - decrement by 1 and test
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1 and
* returns true if the result is 0, or false for all other
* cases.
*/
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
/*
* atomic_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*/
#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
/*
* atomic_inc - increment atomic variable
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1.
*/
#define atomic_inc(v) atomic_add(1, (v))
/*
* atomic_dec - decrement and test
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1.
*/
#define atomic_dec(v) atomic_sub(1, (v))
/*
* atomic_add_negative - add and test if negative
* @v: pointer of type atomic_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns true
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
#define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
/*
* atomic*_return operations are serializing but not the non-*_return
* versions.
*/
#define smp_mb__before_atomic_dec() smp_llsc_mb()
#define smp_mb__after_atomic_dec() smp_llsc_mb()
#define smp_mb__before_atomic_inc() smp_llsc_mb()
#define smp_mb__after_atomic_inc() smp_llsc_mb()
#include <asm-generic/atomic-long.h>
#endif /* _ASM_ATOMIC_H */
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