1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 1999, 2000  Niibe Yutaka  &  Kaz Kojima
4 * Copyright (C) 2002 Paul Mundt
5 */
6#ifndef __ASM_SH_BARRIER_H
7#define __ASM_SH_BARRIER_H
8
9#if defined(CONFIG_CPU_SH4A)
10#include <asm/cache_insns.h>
11#endif
12
13/*
14 * A brief note on ctrl_barrier(), the control register write barrier.
15 *
16 * Legacy SH cores typically require a sequence of 8 nops after
17 * modification of a control register in order for the changes to take
18 * effect. On newer cores (like the sh4a and sh5) this is accomplished
19 * with icbi.
20 *
21 * Also note that on sh4a in the icbi case we can forego a synco for the
22 * write barrier, as it's not necessary for control registers.
23 *
24 * Historically we have only done this type of barrier for the MMUCR, but
25 * it's also necessary for the CCR, so we make it generic here instead.
26 */
27#if defined(CONFIG_CPU_SH4A)
28#define mb()		__asm__ __volatile__ ("synco": : :"memory")
29#define rmb()		mb()
30#define wmb()		mb()
31#define ctrl_barrier()	__icbi(PAGE_OFFSET)
32#else
33#if defined(CONFIG_CPU_J2) && defined(CONFIG_SMP)
34#define __smp_mb()	do { int tmp = 0; __asm__ __volatile__ ("cas.l %0,%0,@%1" : "+r"(tmp) : "z"(&tmp) : "memory", "t"); } while(0)
35#define __smp_rmb()	__smp_mb()
36#define __smp_wmb()	__smp_mb()
37#endif
38#define ctrl_barrier()	__asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop")
39#endif
40
41#define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
42
43#include <asm-generic/barrier.h>
44
45#endif /* __ASM_SH_BARRIER_H */
46