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/* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
* Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
*/
#ifndef _ASM_PARISC_ATOMIC_H_
#define _ASM_PARISC_ATOMIC_H_
#include <linux/types.h>
#include <asm/cmpxchg.h>
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*
* And probably incredibly slow on parisc. OTOH, we don't
* have to write any serious assembly. prumpf
*/
#ifdef CONFIG_SMP
#include <asm/spinlock.h>
#include <asm/cache.h> /* we use L1_CACHE_BYTES */
/* Use an array of spinlocks for our atomic_ts.
* Hash function to index into a different SPINLOCK.
* Since "a" is usually an address, use one spinlock per cacheline.
*/
# define ATOMIC_HASH_SIZE 4
# define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
/* Can't use raw_spin_lock_irq because of #include problems, so
* this is the substitute */
#define _atomic_spin_lock_irqsave(l,f) do { \
arch_spinlock_t *s = ATOMIC_HASH(l); \
local_irq_save(f); \
arch_spin_lock(s); \
} while(0)
#define _atomic_spin_unlock_irqrestore(l,f) do { \
arch_spinlock_t *s = ATOMIC_HASH(l); \
arch_spin_unlock(s); \
local_irq_restore(f); \
} while(0)
#else
# define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
# define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
#endif
/*
* Note that we need not lock read accesses - aligned word writes/reads
* are atomic, so a reader never sees inconsistent values.
*/
/* It's possible to reduce all atomic operations to either
* __atomic_add_return, atomic_set and atomic_read (the latter
* is there only for consistency).
*/
static __inline__ int __atomic_add_return(int i, atomic_t *v)
{
int ret;
unsigned long flags;
_atomic_spin_lock_irqsave(v, flags);
ret = (v->counter += i);
_atomic_spin_unlock_irqrestore(v, flags);
return ret;
}
static __inline__ void atomic_set(atomic_t *v, int i)
{
unsigned long flags;
_atomic_spin_lock_irqsave(v, flags);
v->counter = i;
_atomic_spin_unlock_irqrestore(v, flags);
}
static __inline__ int atomic_read(const atomic_t *v)
{
return (*(volatile int *)&(v)->counter);
}
/* exported interface */
#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 the old value of @v.
*/
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;
}
#define atomic_add(i,v) ((void)(__atomic_add_return( (i),(v))))
#define atomic_sub(i,v) ((void)(__atomic_add_return(-((int) (i)),(v))))
#define atomic_inc(v) ((void)(__atomic_add_return( 1,(v))))
#define atomic_dec(v) ((void)(__atomic_add_return( -1,(v))))
#define atomic_add_return(i,v) (__atomic_add_return( (i),(v)))
#define atomic_sub_return(i,v) (__atomic_add_return(-(i),(v)))
#define atomic_inc_return(v) (__atomic_add_return( 1,(v)))
#define atomic_dec_return(v) (__atomic_add_return( -1,(v)))
#define atomic_add_negative(a, v) (atomic_add_return((a), (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)
#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
#define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0)
#define ATOMIC_INIT(i) { (i) }
#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()
#ifdef CONFIG_64BIT
#define ATOMIC64_INIT(i) { (i) }
static __inline__ s64
__atomic64_add_return(s64 i, atomic64_t *v)
{
s64 ret;
unsigned long flags;
_atomic_spin_lock_irqsave(v, flags);
ret = (v->counter += i);
_atomic_spin_unlock_irqrestore(v, flags);
return ret;
}
static __inline__ void
atomic64_set(atomic64_t *v, s64 i)
{
unsigned long flags;
_atomic_spin_lock_irqsave(v, flags);
v->counter = i;
_atomic_spin_unlock_irqrestore(v, flags);
}
static __inline__ s64
atomic64_read(const atomic64_t *v)
{
return (*(volatile long *)&(v)->counter);
}
#define atomic64_add(i,v) ((void)(__atomic64_add_return( ((s64)(i)),(v))))
#define atomic64_sub(i,v) ((void)(__atomic64_add_return(-((s64)(i)),(v))))
#define atomic64_inc(v) ((void)(__atomic64_add_return( 1,(v))))
#define atomic64_dec(v) ((void)(__atomic64_add_return( -1,(v))))
#define atomic64_add_return(i,v) (__atomic64_add_return( ((s64)(i)),(v)))
#define atomic64_sub_return(i,v) (__atomic64_add_return(-((s64)(i)),(v)))
#define atomic64_inc_return(v) (__atomic64_add_return( 1,(v)))
#define atomic64_dec_return(v) (__atomic64_add_return( -1,(v)))
#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
#define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0)
#define atomic64_sub_and_test(i,v) (atomic64_sub_return((i),(v)) == 0)
/* exported interface */
#define atomic64_cmpxchg(v, o, n) \
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
/**
* atomic64_add_unless - add unless the number is a given value
* @v: pointer of type atomic64_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 the old value of @v.
*/
static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
{
long c, old;
c = atomic64_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic64_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c != (u);
}
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
/*
* atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static inline long atomic64_dec_if_positive(atomic64_t *v)
{
long c, old, dec;
c = atomic64_read(v);
for (;;) {
dec = c - 1;
if (unlikely(dec < 0))
break;
old = atomic64_cmpxchg((v), c, dec);
if (likely(old == c))
break;
c = old;
}
return dec;
}
#endif /* !CONFIG_64BIT */
#endif /* _ASM_PARISC_ATOMIC_H_ */
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