| /* |
| * 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() mb() |
| #define ctrl_barrier() __icbi(PAGE_OFFSET) |
| #else |
| #define ctrl_barrier() __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop") |
| #endif |
| |
| #define set_mb(var, value) do { (void)xchg(&var, value); } while (0) |
| |
| #include <asm-generic/barrier.h> |
| |
| #endif /* __ASM_SH_BARRIER_H */ |
