| 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455 |
- /*
- * 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 */
|
