1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copied from the kernel sources:
4 *
5 * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
6 * Copyright (C) 2002 Paul Mundt
7 */
8 #ifndef __TOOLS_LINUX_ASM_SH_BARRIER_H
9 #define __TOOLS_LINUX_ASM_SH_BARRIER_H
10
11 /*
12 * A brief note on ctrl_barrier(), the control register write barrier.
13 *
14 * Legacy SH cores typically require a sequence of 8 nops after
15 * modification of a control register in order for the changes to take
16 * effect. On newer cores (like the sh4a and sh5) this is accomplished
17 * with icbi.
18 *
19 * Also note that on sh4a in the icbi case we can forego a synco for the
20 * write barrier, as it's not necessary for control registers.
21 *
22 * Historically we have only done this type of barrier for the MMUCR, but
23 * it's also necessary for the CCR, so we make it generic here instead.
24 */
25 #if defined(__SH4A__)
26 #define mb() __asm__ __volatile__ ("synco": : :"memory")
27 #define rmb() mb()
28 #define wmb() mb()
29 #endif
30
31 #include <asm-generic/barrier.h>
32
33 #endif /* __TOOLS_LINUX_ASM_SH_BARRIER_H */
34
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