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1 | /* |
2 | * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima | |
3 | * Copyright (C) 2002 Paul Mundt | |
4 | */ | |
5 | #ifndef __ASM_SH_BARRIER_H | |
6 | #define __ASM_SH_BARRIER_H | |
7 | ||
8 | #if defined(CONFIG_CPU_SH4A) || defined(CONFIG_CPU_SH5) | |
9 | #include <asm/cache_insns.h> | |
10 | #endif | |
11 | ||
12 | /* | |
13 | * A brief note on ctrl_barrier(), the control register write barrier. | |
14 | * | |
15 | * Legacy SH cores typically require a sequence of 8 nops after | |
16 | * modification of a control register in order for the changes to take | |
17 | * effect. On newer cores (like the sh4a and sh5) this is accomplished | |
18 | * with icbi. | |
19 | * | |
20 | * Also note that on sh4a in the icbi case we can forego a synco for the | |
21 | * write barrier, as it's not necessary for control registers. | |
22 | * | |
23 | * Historically we have only done this type of barrier for the MMUCR, but | |
24 | * it's also necessary for the CCR, so we make it generic here instead. | |
25 | */ | |
26 | #if defined(CONFIG_CPU_SH4A) || defined(CONFIG_CPU_SH5) | |
27 | #define mb() __asm__ __volatile__ ("synco": : :"memory") | |
28 | #define rmb() mb() | |
29 | #define wmb() __asm__ __volatile__ ("synco": : :"memory") | |
30 | #define ctrl_barrier() __icbi(PAGE_OFFSET) | |
31 | #define read_barrier_depends() do { } while(0) | |
32 | #else | |
33 | #define mb() __asm__ __volatile__ ("": : :"memory") | |
34 | #define rmb() mb() | |
35 | #define wmb() __asm__ __volatile__ ("": : :"memory") | |
36 | #define ctrl_barrier() __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop") | |
37 | #define read_barrier_depends() do { } while(0) | |
38 | #endif | |
39 | ||
40 | #ifdef CONFIG_SMP | |
41 | #define smp_mb() mb() | |
42 | #define smp_rmb() rmb() | |
43 | #define smp_wmb() wmb() | |
44 | #define smp_read_barrier_depends() read_barrier_depends() | |
45 | #else | |
46 | #define smp_mb() barrier() | |
47 | #define smp_rmb() barrier() | |
48 | #define smp_wmb() barrier() | |
49 | #define smp_read_barrier_depends() do { } while(0) | |
50 | #endif | |
51 | ||
52 | #define set_mb(var, value) do { (void)xchg(&var, value); } while (0) | |
53 | ||
54 | #endif /* __ASM_SH_BARRIER_H */ |