kernel/arch/mn10300/include/asm/cmpxchg.h

   1 /* MN10300 Atomic xchg/cmpxchg operations
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #ifndef _ASM_CMPXCHG_H
  12 #define _ASM_CMPXCHG_H
  13
  14 #include <asm/irqflags.h>
  15
  16 #ifdef CONFIG_SMP
  17 #ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
  18 static inline
  19 unsigned long __xchg(volatile unsigned long *m, unsigned long val)
  20 {
  21         unsigned long status;
  22         unsigned long oldval;
  23
  24         asm volatile(
  25                 "1:     mov     %4,(_AAR,%3)    \n"
  26                 "       mov     (_ADR,%3),%1    \n"
  27                 "       mov     %5,(_ADR,%3)    \n"
  28                 "       mov     (_ADR,%3),%0    \n"     /* flush */
  29                 "       mov     (_ASR,%3),%0    \n"
  30                 "       or      %0,%0           \n"
  31                 "       bne     1b              \n"
  32                 : "=&r"(status), "=&r"(oldval), "=m"(*m)
  33                 : "a"(ATOMIC_OPS_BASE_ADDR), "r"(m), "r"(val)
  34                 : "memory", "cc");
  35
  36         return oldval;
  37 }
  38
  39 static inline unsigned long __cmpxchg(volatile unsigned long *m,
  40                                       unsigned long old, unsigned long new)
  41 {
  42         unsigned long status;
  43         unsigned long oldval;
  44
  45         asm volatile(
  46                 "1:     mov     %4,(_AAR,%3)    \n"
  47                 "       mov     (_ADR,%3),%1    \n"
  48                 "       cmp     %5,%1           \n"
  49                 "       bne     2f              \n"
  50                 "       mov     %6,(_ADR,%3)    \n"
  51                 "2:     mov     (_ADR,%3),%0    \n"     /* flush */
  52                 "       mov     (_ASR,%3),%0    \n"
  53                 "       or      %0,%0           \n"
  54                 "       bne     1b              \n"
  55                 : "=&r"(status), "=&r"(oldval), "=m"(*m)
  56                 : "a"(ATOMIC_OPS_BASE_ADDR), "r"(m),
  57                   "r"(old), "r"(new)
  58                 : "memory", "cc");
  59
  60         return oldval;
  61 }
  62 #else  /* CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT */
  63 #error "No SMP atomic operation support!"
  64 #endif /* CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT */
  65
  66 #else  /* CONFIG_SMP */
  67
  68 /*
  69  * Emulate xchg for non-SMP MN10300
  70  */
  71 struct __xchg_dummy { unsigned long a[100]; };
  72 #define __xg(x) ((struct __xchg_dummy *)(x))
  73
  74 static inline
  75 unsigned long __xchg(volatile unsigned long *m, unsigned long val)
  76 {
  77         unsigned long oldval;
  78         unsigned long flags;
  79
  80         flags = arch_local_cli_save();
  81         oldval = *m;
  82         *m = val;
  83         arch_local_irq_restore(flags);
  84         return oldval;
  85 }
  86
  87 /*
  88  * Emulate cmpxchg for non-SMP MN10300
  89  */
  90 static inline unsigned long __cmpxchg(volatile unsigned long *m,
  91                                       unsigned long old, unsigned long new)
  92 {
  93         unsigned long oldval;
  94         unsigned long flags;
  95
  96         flags = arch_local_cli_save();
  97         oldval = *m;
  98         if (oldval == old)
  99                 *m = new;
 100         arch_local_irq_restore(flags);
 101         return oldval;
 102 }
 103
 104 #endif /* CONFIG_SMP */
 105
 106 #define xchg(ptr, v)                                            \
 107         ((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr),    \
 108                                      (unsigned long)(v)))
 109
 110 #define cmpxchg(ptr, o, n)                                      \
 111         ((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
 112                                         (unsigned long)(o),     \
 113                                         (unsigned long)(n)))
 114
 115 #endif /* _ASM_CMPXCHG_H */