[mirror_ubuntu-focal-kernel.git] / tools / arch / sh / include / asm / barrier.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copied from the kernel sources:
 *
 * Copyright (C) 1999, 2000  Niibe Yutaka  &  Kaz Kojima
 * Copyright (C) 2002 Paul Mundt
 */
#ifndef __TOOLS_LINUX_ASM_SH_BARRIER_H
#define __TOOLS_LINUX_ASM_SH_BARRIER_H

/*
 * A brief note on ctrl_barrier(), the control register write barrier.
 *
 * Legacy SH cores typically require a sequence of 8 nops after
 * modification of a control register in order for the changes to take
 * effect. On newer cores (like the sh4a and sh5) this is accomplished
 * with icbi.
 *
 * Also note that on sh4a in the icbi case we can forego a synco for the
 * write barrier, as it's not necessary for control registers.
 *
 * Historically we have only done this type of barrier for the MMUCR, but
 * it's also necessary for the CCR, so we make it generic here instead.
 */
#if defined(__SH4A__) || defined(__SH5__)
#define mb()		__asm__ __volatile__ ("synco": : :"memory")
#define rmb()		mb()
#define wmb()		mb()
#endif

#include <asm-generic/barrier.h>

#endif /* __TOOLS_LINUX_ASM_SH_BARRIER_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
827634ad ACM	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__) \|\| defined(__SH5__)
	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 */