1/*
 2 * Copyright (C) 1999, 2000  Niibe Yutaka  &  Kaz Kojima
 3 * Copyright (C) 2002 Paul Mundt
 4 */
 5#ifndef __ASM_SH_BARRIER_H
 6#define __ASM_SH_BARRIER_H
 7
 8#if defined(CONFIG_CPU_SH4A) || defined(CONFIG_CPU_SH5)
 9#include <asm/cache_insns.h>
10#endif
11
12/*
13 * A brief note on ctrl_barrier(), the control register write barrier.
14 *
15 * Legacy SH cores typically require a sequence of 8 nops after
16 * modification of a control register in order for the changes to take
17 * effect. On newer cores (like the sh4a and sh5) this is accomplished
18 * with icbi.
19 *
20 * Also note that on sh4a in the icbi case we can forego a synco for the
21 * write barrier, as it's not necessary for control registers.
22 *
23 * Historically we have only done this type of barrier for the MMUCR, but
24 * it's also necessary for the CCR, so we make it generic here instead.
25 */
26#if defined(CONFIG_CPU_SH4A) || defined(CONFIG_CPU_SH5)
27#define mb()		__asm__ __volatile__ ("synco": : :"memory")
28#define rmb()		mb()
29#define wmb()		mb()
30#define ctrl_barrier()	__icbi(PAGE_OFFSET)
31#else
32#if defined(CONFIG_CPU_J2) && defined(CONFIG_SMP)
33#define __smp_mb()	do { int tmp = 0; __asm__ __volatile__ ("cas.l %0,%0,@%1" : "+r"(tmp) : "z"(&tmp) : "memory", "t"); } while(0)
34#define __smp_rmb()	__smp_mb()
35#define __smp_wmb()	__smp_mb()
36#endif
37#define ctrl_barrier()	__asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop")
38#endif
39
40#define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
41
42#include <asm-generic/barrier.h>
43
44#endif /* __ASM_SH_BARRIER_H */