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/*
* Copyright 2011 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* Do not include directly; use <linux/atomic.h>.
*/
#ifndef _ASM_TILE_ATOMIC_64_H
#define _ASM_TILE_ATOMIC_64_H
#ifndef __ASSEMBLY__
#include <asm/barrier.h>
#include <arch/spr_def.h>
/* First, the 32-bit atomic ops that are "real" on our 64-bit platform. */
#define atomic_set(v, i) WRITE_ONCE((v)->counter, (i))
/*
* The smp_mb() operations throughout are to support the fact that
* Linux requires memory barriers before and after the operation,
* on any routine which updates memory and returns a value.
*/
/*
* Note a subtlety of the locking here. We are required to provide a
* full memory barrier before and after the operation. However, we
* only provide an explicit mb before the operation. After the
* operation, we use barrier() to get a full mb for free, because:
*
* (1) The barrier directive to the compiler prohibits any instructions
* being statically hoisted before the barrier;
* (2) the microarchitecture will not issue any further instructions
* until the fetchadd result is available for the "+ i" add instruction;
* (3) the smb_mb before the fetchadd ensures that no other memory
* operations are in flight at this point.
*/
static inline int atomic_add_return(int i, atomic_t *v)
{
int val;
smp_mb(); /* barrier for proper semantics */
val = __insn_fetchadd4((void *)&v->counter, i) + i;
barrier(); /* equivalent to smp_mb(); see block comment above */
return val;
}
#define ATOMIC_OPS(op) \
static inline int atomic_fetch_##op(int i, atomic_t *v) \
{ \
int val; \
smp_mb(); \
val = __insn_fetch##op##4((void *)&v->counter, i); \
smp_mb(); \
return val; \
} \
static inline void atomic_##op(int i, atomic_t *v) \
{ \
__insn_fetch##op##4((void *)&v->counter, i); \
}
ATOMIC_OPS(add)
ATOMIC_OPS(and)
ATOMIC_OPS(or)
#undef ATOMIC_OPS
static inline int atomic_fetch_xor(int i, atomic_t *v)
{
int guess, oldval = v->counter;
smp_mb();
do {
guess = oldval;
__insn_mtspr(SPR_CMPEXCH_VALUE, guess);
oldval = __insn_cmpexch4(&v->counter, guess ^ i);
} while (guess != oldval);
smp_mb();
return oldval;
}
static inline void atomic_xor(int i, atomic_t *v)
{
int guess, oldval = v->counter;
do {
guess = oldval;
__insn_mtspr(SPR_CMPEXCH_VALUE, guess);
oldval = __insn_cmpexch4(&v->counter, guess ^ i);
} while (guess != oldval);
}
static inline int __atomic_add_unless(atomic_t *v, int a, int u)
{
int guess, oldval = v->counter;
do {
if (oldval == u)
break;
guess = oldval;
oldval = cmpxchg(&v->counter, guess, guess + a);
} while (guess != oldval);
return oldval;
}
/* Now the true 64-bit operations. */
#define ATOMIC64_INIT(i) { (i) }
#define atomic64_read(v) READ_ONCE((v)->counter)
#define atomic64_set(v, i) WRITE_ONCE((v)->counter, (i))
static inline long atomic64_add_return(long i, atomic64_t *v)
{
int val;
smp_mb(); /* barrier for proper semantics */
val = __insn_fetchadd((void *)&v->counter, i) + i;
barrier(); /* equivalent to smp_mb; see atomic_add_return() */
return val;
}
#define ATOMIC64_OPS(op) \
static inline long atomic64_fetch_##op(long i, atomic64_t *v) \
{ \
long val; \
smp_mb(); \
val = __insn_fetch##op((void *)&v->counter, i); \
smp_mb(); \
return val; \
} \
static inline void atomic64_##op(long i, atomic64_t *v) \
{ \
__insn_fetch##op((void *)&v->counter, i); \
}
ATOMIC64_OPS(add)
ATOMIC64_OPS(and)
ATOMIC64_OPS(or)
#undef ATOMIC64_OPS
static inline long atomic64_fetch_xor(long i, atomic64_t *v)
{
long guess, oldval = v->counter;
smp_mb();
do {
guess = oldval;
__insn_mtspr(SPR_CMPEXCH_VALUE, guess);
oldval = __insn_cmpexch(&v->counter, guess ^ i);
} while (guess != oldval);
smp_mb();
return oldval;
}
static inline void atomic64_xor(long i, atomic64_t *v)
{
long guess, oldval = v->counter;
do {
guess = oldval;
__insn_mtspr(SPR_CMPEXCH_VALUE, guess);
oldval = __insn_cmpexch(&v->counter, guess ^ i);
} while (guess != oldval);
}
static inline long atomic64_add_unless(atomic64_t *v, long a, long u)
{
long guess, oldval = v->counter;
do {
if (oldval == u)
break;
guess = oldval;
oldval = cmpxchg(&v->counter, guess, guess + a);
} while (guess != oldval);
return oldval != u;
}
#define atomic64_sub_return(i, v) atomic64_add_return(-(i), (v))
#define atomic64_fetch_sub(i, v) atomic64_fetch_add(-(i), (v))
#define atomic64_sub(i, v) atomic64_add(-(i), (v))
#define atomic64_inc_return(v) atomic64_add_return(1, (v))
#define atomic64_dec_return(v) atomic64_sub_return(1, (v))
#define atomic64_inc(v) atomic64_add(1, (v))
#define atomic64_dec(v) atomic64_sub(1, (v))
#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)
#define atomic64_add_negative(i, v) (atomic64_add_return((i), (v)) < 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_TILE_ATOMIC_64_H */
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