/* atomic.h: atomic operation emulation for FR-V
*
* For an explanation of how atomic ops work in this arch, see:
* Documentation/frv/atomic-ops.txt
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H
#include <linux/types.h>
#include <asm/spr-regs.h>
#include <asm/system.h>
#ifdef CONFIG_SMP
#error not SMP safe
#endif
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*
* We do not have SMP systems, so we don't have to deal with that.
*/
/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec() barrier()
#define smp_mb__before_atomic_inc() barrier()
#define smp_mb__after_atomic_inc() barrier()
#define ATOMIC_INIT(i) { (i) }
#define atomic_read(v) ((v)->counter)
#define atomic_set(v, i) (((v)->counter) = (i))
#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
static inline int atomic_add_return(int i, atomic_t *v)
{
unsigned long val;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
" ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
" add%I2 %1,%2,%1 \n"
" cst.p %1,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
: "+U"(v->counter), "=&r"(val)
: "NPr"(i)
: "memory", "cc7", "cc3", "icc3"
);
return val;
}
static inline int atomic_sub_return(int i, atomic_t *v)
{
unsigned long val;
asm("0: \n"
" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
" ckeq icc3,cc7 \n"
" ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
" sub%I2 %1,%2,%1 \n"
" cst.p %1,%M0 ,cc3,#1 \n"
" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
" beq icc3,#0,0b \n"
: "+U"(v->counter), "=&r"(val)
: "NPr"(i)
: "memory", "cc7", "cc3", "icc3"
);
return val;
}
#else
extern int atomic_add_return(int i, atomic_t *v);
extern int atomic_sub_return(int i, atomic_t *v);
#endif
static inline int atomic_add_negative(int i, atomic_t *v)
{
return atomic_add_return(i, v) < 0;
}
static inline void atomic_add(int i, atomic_t *v)
{
atomic_add_return(i, v);
}
static inline void atomic_sub(int i, atomic_t *v)
{
atomic_sub_return(i, v);
}
static inline void atomic_inc(atomic_t *v)
{
atomic_add_return(1, v);
}
static inline void atomic_dec(atomic_t *v)
{
atomic_sub_return(1, v);
}
#define atomic_dec_return(v) atomic_sub_return(1, (v))
#define atomic_inc_return(v) atomic_add_return(1, (v))
#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
/*****************************************************************************/
/*
* exchange value with memory
*/
#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
#define xchg(ptr, x) \
({ \
__typeof__(ptr) __xg_ptr = (ptr); \
__typeof__(*(ptr)) __xg_orig; \
\
switch (sizeof(__xg_orig)) { \
case 4: \
asm volatile( \
"swap%I0 %M0,%1" \
: "+m"(*__xg_ptr), "=r"(__xg_orig) \
: "1"(x) \
: "memory" \
); \
break; \
\
default: \
__xg_orig = (__typeof__(__xg_orig))0; \
asm volatile("break"); \
break; \
} \
\
__xg_orig; \
})
#else
extern uint32_t __xchg_32(uint32_t i, volatile void *v);
#define xchg(ptr, x) \
({ \
__typeof__(ptr) __xg_ptr = (ptr); \
__typeof__(*(ptr)) __xg_orig; \
\
switch (sizeof(__xg_orig)) { \
case 4: __xg_orig = (__typeof__(*(ptr))) __xchg_32((uint32_t) x, __xg_ptr); break; \
default: \
__xg_orig = (__typeof__(__xg_orig))0; \
asm volatile("break"); \
break; \
} \
__xg_orig; \
})
#endif
#define tas(ptr) (xchg((ptr), 1))
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
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)
#include <asm-generic/atomic.h>
#endif /* _ASM_ATOMIC_H */
