arch/avr32/include/asm/cmpxchg.h

   1 /*
   2  * Atomic operations that C can't guarantee us.  Useful for
   3  * resource counting etc.
   4  *
   5  * But use these as seldom as possible since they are slower than
   6  * regular operations.
   7  *
   8  * Copyright (C) 2004-2006 Atmel Corporation
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14 #ifndef __ASM_AVR32_CMPXCHG_H
  15 #define __ASM_AVR32_CMPXCHG_H
  16
  17 #define xchg(ptr,x) \
  18         ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  19
  20 extern void __xchg_called_with_bad_pointer(void);
  21
  22 static inline unsigned long xchg_u32(u32 val, volatile u32 *m)
  23 {
  24         u32 ret;
  25
  26         asm volatile("xchg %[ret], %[m], %[val]"
  27                         : [ret] "=&r"(ret), "=m"(*m)
  28                         : "m"(*m), [m] "r"(m), [val] "r"(val)
  29                         : "memory");
  30         return ret;
  31 }
  32
  33 static inline unsigned long __xchg(unsigned long x,
  34                                        volatile void *ptr,
  35                                        int size)
  36 {
  37         switch(size) {
  38         case 4:
  39                 return xchg_u32(x, ptr);
  40         default:
  41                 __xchg_called_with_bad_pointer();
  42                 return x;
  43         }
  44 }
  45
  46 static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
  47                                           unsigned long new)
  48 {
  49         __u32 ret;
  50
  51         asm volatile(
  52                 "1:     ssrf    5\n"
  53                 "       ld.w    %[ret], %[m]\n"
  54                 "       cp.w    %[ret], %[old]\n"
  55                 "       brne    2f\n"
  56                 "       stcond  %[m], %[new]\n"
  57                 "       brne    1b\n"
  58                 "2:\n"
  59                 : [ret] "=&r"(ret), [m] "=m"(*m)
  60                 : "m"(m), [old] "Ks21r"(old), [new] "r"(new)
  61                 : "memory", "cc");
  62         return ret;
  63 }
  64
  65 extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
  66         volatile int * m, unsigned long old, unsigned long new);
  67 #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
  68
  69 /* This function doesn't exist, so you'll get a linker error
  70    if something tries to do an invalid cmpxchg().  */
  71 extern void __cmpxchg_called_with_bad_pointer(void);
  72
  73 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
  74                                       unsigned long new, int size)
  75 {
  76         switch (size) {
  77         case 4:
  78                 return __cmpxchg_u32(ptr, old, new);
  79         case 8:
  80                 return __cmpxchg_u64(ptr, old, new);
  81         }
  82
  83         __cmpxchg_called_with_bad_pointer();
  84         return old;
  85 }
  86
  87 #define cmpxchg(ptr, old, new)                                  \
  88         ((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), \
  89                                    (unsigned long)(new),        \
  90                                    sizeof(*(ptr))))
  91
  92 #include <asm-generic/cmpxchg-local.h>
  93
  94 static inline unsigned long __cmpxchg_local(volatile void *ptr,
  95                                       unsigned long old,
  96                                       unsigned long new, int size)
  97 {
  98         switch (size) {
  99         case 4:
 100                 return __cmpxchg_u32(ptr, old, new);
 101         default:
 102                 return __cmpxchg_local_generic(ptr, old, new, size);
 103         }
 104
 105         return old;
 106 }
 107
 108 #define cmpxchg_local(ptr, old, new)                                    \
 109         ((typeof(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(old),   \
 110                                    (unsigned long)(new),                \
 111                                    sizeof(*(ptr))))
 112
 113 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 114
 115 #endif /* __ASM_AVR32_CMPXCHG_H */