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Linux kernel mirror (for testing)
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linux
1/*
2 * Copied from the kernel sources:
3 *
4 * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
5 * Copyright (C) 2002 Paul Mundt
6 */
7#ifndef __TOOLS_LINUX_ASM_SH_BARRIER_H
8#define __TOOLS_LINUX_ASM_SH_BARRIER_H
9
10/*
11 * A brief note on ctrl_barrier(), the control register write barrier.
12 *
13 * Legacy SH cores typically require a sequence of 8 nops after
14 * modification of a control register in order for the changes to take
15 * effect. On newer cores (like the sh4a and sh5) this is accomplished
16 * with icbi.
17 *
18 * Also note that on sh4a in the icbi case we can forego a synco for the
19 * write barrier, as it's not necessary for control registers.
20 *
21 * Historically we have only done this type of barrier for the MMUCR, but
22 * it's also necessary for the CCR, so we make it generic here instead.
23 */
24#if defined(__SH4A__) || defined(__SH5__)
25#define mb() __asm__ __volatile__ ("synco": : :"memory")
26#define rmb() mb()
27#define wmb() mb()
28#endif
29
30#include <asm-generic/barrier.h>
31
32#endif /* __TOOLS_LINUX_ASM_SH_BARRIER_H */