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/* * 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 <asm/cache_insns.h> #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 */ |