From e839ca528718e68cad32a307dc9aabf01ef3eb05 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 28 Mar 2012 18:30:03 +0100 Subject: Disintegrate asm/system.h for SH Disintegrate asm/system.h for SH. Signed-off-by: David Howells cc: linux-sh@vger.kernel.org --- arch/sh/include/asm/barrier.h | 54 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 arch/sh/include/asm/barrier.h (limited to 'arch/sh/include/asm/barrier.h') diff --git a/arch/sh/include/asm/barrier.h b/arch/sh/include/asm/barrier.h new file mode 100644 index 000000000000..72c103dae300 --- /dev/null +++ b/arch/sh/include/asm/barrier.h @@ -0,0 +1,54 @@ +/* + * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima + * Copyright (C) 2002 Paul Mundt + */ +#ifndef __ASM_SH_BARRIER_H +#define __ASM_SH_BARRIER_H + +#if defined(CONFIG_CPU_SH4A) || defined(CONFIG_CPU_SH5) +#include +#endif + +/* + * 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(CONFIG_CPU_SH4A) || defined(CONFIG_CPU_SH5) +#define mb() __asm__ __volatile__ ("synco": : :"memory") +#define rmb() mb() +#define wmb() __asm__ __volatile__ ("synco": : :"memory") +#define ctrl_barrier() __icbi(PAGE_OFFSET) +#define read_barrier_depends() do { } while(0) +#else +#define mb() __asm__ __volatile__ ("": : :"memory") +#define rmb() mb() +#define wmb() __asm__ __volatile__ ("": : :"memory") +#define ctrl_barrier() __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop") +#define read_barrier_depends() do { } while(0) +#endif + +#ifdef CONFIG_SMP +#define smp_mb() mb() +#define smp_rmb() rmb() +#define smp_wmb() wmb() +#define smp_read_barrier_depends() read_barrier_depends() +#else +#define smp_mb() barrier() +#define smp_rmb() barrier() +#define smp_wmb() barrier() +#define smp_read_barrier_depends() do { } while(0) +#endif + +#define set_mb(var, value) do { (void)xchg(&var, value); } while (0) + +#endif /* __ASM_SH_BARRIER_H */ -- cgit v1.2.3