arch/nios2/include/asm/cmpxchg.h

   1 /*
   2  * Copyright (C) 2004 Microtronix Datacom Ltd.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License. See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  */
   8
   9 #ifndef _ASM_NIOS2_CMPXCHG_H
  10 #define _ASM_NIOS2_CMPXCHG_H
  11
  12 #include <linux/irqflags.h>
  13
  14 #define xchg(ptr, x)    \
  15         ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  16
  17 struct __xchg_dummy { unsigned long a[100]; };
  18 #define __xg(x)         ((volatile struct __xchg_dummy *)(x))
  19
  20 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
  21                                         int size)
  22 {
  23         unsigned long tmp, flags;
  24
  25         local_irq_save(flags);
  26
  27         switch (size) {
  28         case 1:
  29                 __asm__ __volatile__(
  30                         "ldb    %0, %2\n"
  31                         "stb    %1, %2\n"
  32                         : "=&r" (tmp)
  33                         : "r" (x), "m" (*__xg(ptr))
  34                         : "memory");
  35                 break;
  36         case 2:
  37                 __asm__ __volatile__(
  38                         "ldh    %0, %2\n"
  39                         "sth    %1, %2\n"
  40                         : "=&r" (tmp)
  41                         : "r" (x), "m" (*__xg(ptr))
  42                         : "memory");
  43                 break;
  44         case 4:
  45                 __asm__ __volatile__(
  46                         "ldw    %0, %2\n"
  47                         "stw    %1, %2\n"
  48                         : "=&r" (tmp)
  49                         : "r" (x), "m" (*__xg(ptr))
  50                         : "memory");
  51                 break;
  52         }
  53
  54         local_irq_restore(flags);
  55         return tmp;
  56 }
  57
  58 #include <asm-generic/cmpxchg.h>
  59 #include <asm-generic/cmpxchg-local.h>
  60
  61 #endif /* _ASM_NIOS2_CMPXCHG_H */