| 1 | /* |
| 2 | * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu> |
| 3 | */ |
| 4 | #ifndef __PPC_SYSTEM_H |
| 5 | #define __PPC_SYSTEM_H |
| 6 | |
| 7 | #include <asm/atomic.h> |
| 8 | #include <asm/hw_irq.h> |
| 9 | |
| 10 | /* |
| 11 | * Memory barrier. |
| 12 | * The sync instruction guarantees that all memory accesses initiated |
| 13 | * by this processor have been performed (with respect to all other |
| 14 | * mechanisms that access memory). The eieio instruction is a barrier |
| 15 | * providing an ordering (separately) for (a) cacheable stores and (b) |
| 16 | * loads and stores to non-cacheable memory (e.g. I/O devices). |
| 17 | * |
| 18 | * mb() prevents loads and stores being reordered across this point. |
| 19 | * rmb() prevents loads being reordered across this point. |
| 20 | * wmb() prevents stores being reordered across this point. |
| 21 | * read_barrier_depends() prevents data-dependent loads being reordered |
| 22 | * across this point (nop on PPC). |
| 23 | * |
| 24 | * We can use the eieio instruction for wmb, but since it doesn't |
| 25 | * give any ordering guarantees about loads, we have to use the |
| 26 | * stronger but slower sync instruction for mb and rmb. |
| 27 | */ |
| 28 | #define mb() __asm__ __volatile__ ("sync" : : : "memory") |
| 29 | #define rmb() __asm__ __volatile__ ("sync" : : : "memory") |
| 30 | #define wmb() __asm__ __volatile__ ("eieio" : : : "memory") |
| 31 | #define read_barrier_depends() do { } while(0) |
| 32 | |
| 33 | #define set_mb(var, value) do { var = value; mb(); } while (0) |
| 34 | #define set_wmb(var, value) do { var = value; wmb(); } while (0) |
| 35 | |
| 36 | #ifdef CONFIG_SMP |
| 37 | #define smp_mb() mb() |
| 38 | #define smp_rmb() rmb() |
| 39 | #define smp_wmb() wmb() |
| 40 | #define smp_read_barrier_depends() read_barrier_depends() |
| 41 | #else |
| 42 | #define smp_mb() barrier() |
| 43 | #define smp_rmb() barrier() |
| 44 | #define smp_wmb() barrier() |
| 45 | #define smp_read_barrier_depends() do { } while(0) |
| 46 | #endif /* CONFIG_SMP */ |
| 47 | |
| 48 | static inline unsigned long |
| 49 | xchg_u32(volatile void *p, unsigned long val) |
| 50 | { |
| 51 | unsigned long prev; |
| 52 | |
| 53 | __asm__ __volatile__ ("\n\ |
| 54 | 1: lwarx %0,0,%2 \n" |
| 55 | PPC405_ERR77(0,%2) |
| 56 | " stwcx. %3,0,%2 \n\ |
| 57 | bne- 1b" |
| 58 | : "=&r" (prev), "=m" (*(volatile unsigned long *)p) |
| 59 | : "r" (p), "r" (val), "m" (*(volatile unsigned long *)p) |
| 60 | : "cc", "memory"); |
| 61 | |
| 62 | return prev; |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * This function doesn't exist, so you'll get a linker error |
| 67 | * if something tries to do an invalid xchg(). |
| 68 | */ |
| 69 | extern void __xchg_called_with_bad_pointer(void); |
| 70 | |
| 71 | #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) |
| 72 | #define tas(ptr) (xchg((ptr),1)) |
| 73 | |
| 74 | static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size) |
| 75 | { |
| 76 | switch (size) { |
| 77 | case 4: |
| 78 | return (unsigned long) xchg_u32(ptr, x); |
| 79 | #if 0 /* xchg_u64 doesn't exist on 32-bit PPC */ |
| 80 | case 8: |
| 81 | return (unsigned long) xchg_u64(ptr, x); |
| 82 | #endif /* 0 */ |
| 83 | } |
| 84 | __xchg_called_with_bad_pointer(); |
| 85 | return x; |
| 86 | |
| 87 | |
| 88 | } |
| 89 | |
| 90 | extern inline void * xchg_ptr(void * m, void * val) |
| 91 | { |
| 92 | return (void *) xchg_u32(m, (unsigned long) val); |
| 93 | } |
| 94 | |
| 95 | |
| 96 | #define __HAVE_ARCH_CMPXCHG 1 |
| 97 | |
| 98 | static inline unsigned long |
| 99 | __cmpxchg_u32(volatile unsigned int *p, unsigned int old, unsigned int new) |
| 100 | { |
| 101 | unsigned int prev; |
| 102 | |
| 103 | __asm__ __volatile__ ("\n\ |
| 104 | 1: lwarx %0,0,%2 \n\ |
| 105 | cmpw 0,%0,%3 \n\ |
| 106 | bne 2f \n" |
| 107 | PPC405_ERR77(0,%2) |
| 108 | " stwcx. %4,0,%2 \n\ |
| 109 | bne- 1b\n" |
| 110 | #if 0 //only using one CPU at a time (LTT) // def CONFIG_SMP |
| 111 | " sync\n" |
| 112 | #endif /* CONFIG_SMP */ |
| 113 | "2:" |
| 114 | : "=&r" (prev), "=m" (*p) |
| 115 | : "r" (p), "r" (old), "r" (new), "m" (*p) |
| 116 | : "cc", "memory"); |
| 117 | |
| 118 | return prev; |
| 119 | } |
| 120 | |
| 121 | /* This function doesn't exist, so you'll get a linker error |
| 122 | if something tries to do an invalid cmpxchg(). */ |
| 123 | extern void __cmpxchg_called_with_bad_pointer(void); |
| 124 | |
| 125 | static inline unsigned long |
| 126 | __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) |
| 127 | { |
| 128 | switch (size) { |
| 129 | case 4: |
| 130 | return __cmpxchg_u32(ptr, old, new); |
| 131 | #if 0 /* we don't have __cmpxchg_u64 on 32-bit PPC */ |
| 132 | case 8: |
| 133 | return __cmpxchg_u64(ptr, old, new); |
| 134 | #endif /* 0 */ |
| 135 | } |
| 136 | __cmpxchg_called_with_bad_pointer(); |
| 137 | return old; |
| 138 | } |
| 139 | |
| 140 | #define cmpxchg(ptr,o,n) \ |
| 141 | ({ \ |
| 142 | __typeof__(*(ptr)) _o_ = (o); \ |
| 143 | __typeof__(*(ptr)) _n_ = (n); \ |
| 144 | (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ |
| 145 | (unsigned long)_n_, sizeof(*(ptr))); \ |
| 146 | }) |
| 147 | |
| 148 | #define arch_align_stack(x) (x) |
| 149 | |
| 150 | #endif /* __PPC_SYSTEM_H */ |