kernel/arch/blackfin/include/asm/cmpxchg.h

   1 /*
   2  * Copyright 2004-2011 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2 or later.
   5  */
   6
   7 #ifndef __ARCH_BLACKFIN_CMPXCHG__
   8 #define __ARCH_BLACKFIN_CMPXCHG__
   9
  10 #ifdef CONFIG_SMP
  11
  12 #include <linux/linkage.h>
  13
  14 asmlinkage unsigned long __raw_xchg_1_asm(volatile void *ptr, unsigned long value);
  15 asmlinkage unsigned long __raw_xchg_2_asm(volatile void *ptr, unsigned long value);
  16 asmlinkage unsigned long __raw_xchg_4_asm(volatile void *ptr, unsigned long value);
  17 asmlinkage unsigned long __raw_cmpxchg_1_asm(volatile void *ptr,
  18                                         unsigned long new, unsigned long old);
  19 asmlinkage unsigned long __raw_cmpxchg_2_asm(volatile void *ptr,
  20                                         unsigned long new, unsigned long old);
  21 asmlinkage unsigned long __raw_cmpxchg_4_asm(volatile void *ptr,
  22                                         unsigned long new, unsigned long old);
  23
  24 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
  25                                    int size)
  26 {
  27         unsigned long tmp;
  28
  29         switch (size) {
  30         case 1:
  31                 tmp = __raw_xchg_1_asm(ptr, x);
  32                 break;
  33         case 2:
  34                 tmp = __raw_xchg_2_asm(ptr, x);
  35                 break;
  36         case 4:
  37                 tmp = __raw_xchg_4_asm(ptr, x);
  38                 break;
  39         }
  40
  41         return tmp;
  42 }
  43
  44 /*
  45  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  46  * store NEW in MEM.  Return the initial value in MEM.  Success is
  47  * indicated by comparing RETURN with OLD.
  48  */
  49 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
  50                                       unsigned long new, int size)
  51 {
  52         unsigned long tmp;
  53
  54         switch (size) {
  55         case 1:
  56                 tmp = __raw_cmpxchg_1_asm(ptr, new, old);
  57                 break;
  58         case 2:
  59                 tmp = __raw_cmpxchg_2_asm(ptr, new, old);
  60                 break;
  61         case 4:
  62                 tmp = __raw_cmpxchg_4_asm(ptr, new, old);
  63                 break;
  64         }
  65
  66         return tmp;
  67 }
  68 #define cmpxchg(ptr, o, n) \
  69         ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
  70                 (unsigned long)(n), sizeof(*(ptr))))
  71
  72 #else /* !CONFIG_SMP */
  73
  74 #include <mach/blackfin.h>
  75 #include <asm/irqflags.h>
  76
  77 struct __xchg_dummy {
  78         unsigned long a[100];
  79 };
  80 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
  81
  82 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
  83                                    int size)
  84 {
  85         unsigned long tmp = 0;
  86         unsigned long flags;
  87
  88         flags = hard_local_irq_save();
  89
  90         switch (size) {
  91         case 1:
  92                 __asm__ __volatile__
  93                         ("%0 = b%2 (z);\n\t"
  94                          "b%2 = %1;\n\t"
  95                          : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
  96                 break;
  97         case 2:
  98                 __asm__ __volatile__
  99                         ("%0 = w%2 (z);\n\t"
 100                          "w%2 = %1;\n\t"
 101                          : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 102                 break;
 103         case 4:
 104                 __asm__ __volatile__
 105                         ("%0 = %2;\n\t"
 106                          "%2 = %1;\n\t"
 107                          : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 108                 break;
 109         }
 110         hard_local_irq_restore(flags);
 111         return tmp;
 112 }
 113
 114 #include <asm-generic/cmpxchg-local.h>
 115
 116 /*
 117  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 118  * them available.
 119  */
 120 #define cmpxchg_local(ptr, o, n)                                               \
 121         ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
 122                         (unsigned long)(n), sizeof(*(ptr))))
 123 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 124
 125 #define cmpxchg(ptr, o, n)      cmpxchg_local((ptr), (o), (n))
 126 #define cmpxchg64(ptr, o, n)    cmpxchg64_local((ptr), (o), (n))
 127
 128 #endif /* !CONFIG_SMP */
 129
 130 #define xchg(ptr, x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
 131 #define tas(ptr) ((void)xchg((ptr), 1))
 132
 133 #endif /* __ARCH_BLACKFIN_CMPXCHG__ */