mirror of
https://github.com/torvalds/linux.git
synced 2024-11-11 22:51:42 +00:00
1efe4ce3ca
This implements kernel-level atomic rollback built on top of gUSA, as an alternative non-IRQ based atomicity method. This is generally a faster method for platforms that are lacking the LL/SC pairs that SH-4A and later use, and is only supportable on legacy cores. Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
90 lines
2.0 KiB
C
90 lines
2.0 KiB
C
#ifndef __ASM_SH_ATOMIC_H
|
|
#define __ASM_SH_ATOMIC_H
|
|
|
|
/*
|
|
* Atomic operations that C can't guarantee us. Useful for
|
|
* resource counting etc..
|
|
*
|
|
*/
|
|
|
|
typedef struct { volatile int counter; } atomic_t;
|
|
|
|
#define ATOMIC_INIT(i) ( (atomic_t) { (i) } )
|
|
|
|
#define atomic_read(v) ((v)->counter)
|
|
#define atomic_set(v,i) ((v)->counter = (i))
|
|
|
|
#include <linux/compiler.h>
|
|
#include <asm/system.h>
|
|
|
|
#if defined(CONFIG_GUSA_RB)
|
|
#include <asm/atomic-grb.h>
|
|
#elif defined(CONFIG_CPU_SH4A)
|
|
#include <asm/atomic-llsc.h>
|
|
#else
|
|
#include <asm/atomic-irq.h>
|
|
#endif
|
|
|
|
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
|
|
|
|
#define atomic_dec_return(v) atomic_sub_return(1,(v))
|
|
#define atomic_inc_return(v) atomic_add_return(1,(v))
|
|
|
|
/*
|
|
* 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_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(v) atomic_add(1,(v))
|
|
#define atomic_dec(v) atomic_sub(1,(v))
|
|
|
|
#ifndef CONFIG_GUSA_RB
|
|
static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
|
|
{
|
|
int ret;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
ret = v->counter;
|
|
if (likely(ret == old))
|
|
v->counter = new;
|
|
local_irq_restore(flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static inline int atomic_add_unless(atomic_t *v, int a, int u)
|
|
{
|
|
int ret;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
ret = v->counter;
|
|
if (ret != u)
|
|
v->counter += a;
|
|
local_irq_restore(flags);
|
|
|
|
return ret != u;
|
|
}
|
|
#endif
|
|
|
|
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
|
|
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
|
|
|
|
/* Atomic operations are already serializing on SH */
|
|
#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()
|
|
|
|
#include <asm-generic/atomic.h>
|
|
#endif /* __ASM_SH_ATOMIC_H */
|