linux/include/asm-sh/atomic.h
Paul Mundt 781125ca58 sh: New atomic ops for SH-4A movli.l/movco.l
SH-4A implements LL/SC instructions, so we implement a simple
set of atomic operations using these.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-09-27 17:52:19 +09:00

235 lines
4.9 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>
/*
* To get proper branch prediction for the main line, we must branch
* forward to code at the end of this object's .text section, then
* branch back to restart the operation.
*/
static inline void atomic_add(int i, atomic_t *v)
{
#ifdef CONFIG_CPU_SH4A
unsigned long tmp;
__asm__ __volatile__ (
"1: movli.l @%3, %0 ! atomic_add \n"
" add %2, %0 \n"
" movco.l %0, @%3 \n"
" bf 1b \n"
: "=&z" (tmp), "=r" (&v->counter)
: "r" (i), "r" (&v->counter)
: "t");
#else
unsigned long flags;
local_irq_save(flags);
*(long *)v += i;
local_irq_restore(flags);
#endif
}
static inline void atomic_sub(int i, atomic_t *v)
{
#ifdef CONFIG_CPU_SH4A
unsigned long tmp;
__asm__ __volatile__ (
"1: movli.l @%3, %0 ! atomic_sub \n"
" sub %2, %0 \n"
" movco.l %0, @%3 \n"
" bf 1b \n"
: "=&z" (tmp), "=r" (&v->counter)
: "r" (i), "r" (&v->counter)
: "t");
#else
unsigned long flags;
local_irq_save(flags);
*(long *)v -= i;
local_irq_restore(flags);
#endif
}
/*
* SH-4A note:
*
* We basically get atomic_xxx_return() for free compared with
* atomic_xxx(). movli.l/movco.l require r0 due to the instruction
* encoding, so the retval is automatically set without having to
* do any special work.
*/
static inline int atomic_add_return(int i, atomic_t *v)
{
unsigned long temp;
#ifdef CONFIG_CPU_SH4A
__asm__ __volatile__ (
"1: movli.l @%3, %0 ! atomic_add_return \n"
" add %2, %0 \n"
" movco.l %0, @%3 \n"
" bf 1b \n"
" synco \n"
: "=&z" (temp), "=r" (&v->counter)
: "r" (i), "r" (&v->counter)
: "t");
#else
unsigned long flags;
local_irq_save(flags);
temp = *(long *)v;
temp += i;
*(long *)v = temp;
local_irq_restore(flags);
#endif
return temp;
}
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
static inline int atomic_sub_return(int i, atomic_t *v)
{
unsigned long temp;
#ifdef CONFIG_CPU_SH4A
__asm__ __volatile__ (
"1: movli.l @%3, %0 ! atomic_sub_return \n"
" sub %2, %0 \n"
" movco.l %0, @%3 \n"
" bf 1b \n"
" synco \n"
: "=&z" (temp), "=r" (&v->counter)
: "r" (i), "r" (&v->counter)
: "t");
#else
unsigned long flags;
local_irq_save(flags);
temp = *(long *)v;
temp -= i;
*(long *)v = temp;
local_irq_restore(flags);
#endif
return temp;
}
#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))
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;
}
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
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;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
{
#ifdef CONFIG_CPU_SH4A
unsigned long tmp;
__asm__ __volatile__ (
"1: movli.l @%3, %0 ! atomic_clear_mask \n"
" and %2, %0 \n"
" movco.l %0, @%3 \n"
" bf 1b \n"
: "=&z" (tmp), "=r" (&v->counter)
: "r" (~mask), "r" (&v->counter)
: "t");
#else
unsigned long flags;
local_irq_save(flags);
*(long *)v &= ~mask;
local_irq_restore(flags);
#endif
}
static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
{
#ifdef CONFIG_CPU_SH4A
unsigned long tmp;
__asm__ __volatile__ (
"1: movli.l @%3, %0 ! atomic_set_mask \n"
" or %2, %0 \n"
" movco.l %0, @%3 \n"
" bf 1b \n"
: "=&z" (tmp), "=r" (&v->counter)
: "r" (mask), "r" (&v->counter)
: "t");
#else
unsigned long flags;
local_irq_save(flags);
*(long *)v |= mask;
local_irq_restore(flags);
#endif
}
/* 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 */