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#ifndef _ASM_PARISC_ATOMIC_H_
#define _ASM_PARISC_ATOMIC_H_
#include <linux/config.h>
#include <asm/system.h>
/* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>. */
/*
* 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 raw_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 { \
raw_spinlock_t *s = ATOMIC_HASH(l); \
local_irq_save(f); \
__raw_spin_lock(s); \
} while(0)
#define _atomic_spin_unlock_irqrestore(l,f) do { \
raw_spinlock_t *s = ATOMIC_HASH(l); \
__raw_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 unconsistent values.
*
* Cache-line alignment would conflict with, for example, linux/module.h
*/
typedef struct { volatile int counter; } atomic_t;
/* This should get optimized out since it's never called.
** Or get a link error if xchg is used "wrong".
*/
extern void __xchg_called_with_bad_pointer(void);
/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
extern unsigned long __xchg8(char, char *);
extern unsigned long __xchg32(int, int *);
#ifdef __LP64__
extern unsigned long __xchg64(unsigned long, unsigned long *);
#endif
/* optimizer better get rid of switch since size is a constant */
static __inline__ unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
int size)
{
switch(size) {
#ifdef __LP64__
case 8: return __xchg64(x,(unsigned long *) ptr);
#endif
case 4: return __xchg32((int) x, (int *) ptr);
case 1: return __xchg8((char) x, (char *) ptr);
}
__xchg_called_with_bad_pointer();
return x;
}
/*
** REVISIT - Abandoned use of LDCW in xchg() for now:
** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
** o and while we are at it, could __LP64__ code use LDCD too?
**
** if (__builtin_constant_p(x) && (x == NULL))
** if (((unsigned long)p & 0xf) == 0)
** return __ldcw(p);
*/
#define xchg(ptr,x) \
((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
#define __HAVE_ARCH_CMPXCHG 1
/* bug catcher for when unsupported size is used - won't link */
extern void __cmpxchg_called_with_bad_pointer(void);
/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, unsigned int new_);
extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new_);
/* don't worry...optimizer will get rid of most of this */
static __inline__ unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
{
switch(size) {
#ifdef __LP64__
case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
#endif
case 4: return __cmpxchg_u32((unsigned int *)ptr, (unsigned int) old, (unsigned int) new_);
}
__cmpxchg_called_with_bad_pointer();
return old;
}
#define cmpxchg(ptr,o,n) \
({ \
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
(unsigned long)_n_, sizeof(*(ptr))); \
})
/* 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 v->counter;
}
/* exported interface */
#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
#define atomic_add(i,v) ((void)(__atomic_add_return( ((int)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( ((int)i),(v)))
#define atomic_sub_return(i,v) (__atomic_add_return(-((int)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_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()
#endif
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