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   1 /*
   2  * include/asm-microblaze/system.h -- Low-level interrupt/thread ops
   3  *
   4  *  Copyright (C) 2003  John Williams (jwilliams@itee.uq.edu.au)
   5  *                      based upon microblaze version
   6  *  Copyright (C) 2001  NEC Corporation
   7  *  Copyright (C) 2001  Miles Bader <miles@gnu.org>
   8  *
   9  * This file is subject to the terms and conditions of the GNU General
  10  * Public License.  See the file COPYING in the main directory of this
  11  * archive for more details.
  12  *
  13  * Written by Miles Bader <miles@gnu.org>
  14  * Microblaze port by John Williams
  15  * Microblaze port by John Williams
  16  */
  17
  18 #ifndef __MICROBLAZE_SYSTEM_H__
  19 #define __MICROBLAZE_SYSTEM_H__
  20
  21 #if 0
  22 #include <linux/linkage.h>
  23 #endif
  24 #include <asm/ptrace.h>
  25
  26 #define prepare_to_switch()     do { } while (0)
  27
  28 /*
  29  * switch_to(n) should switch tasks to task ptr, first checking that
  30  * ptr isn't the current task, in which case it does nothing.
  31  */
  32 struct thread_struct;
  33 extern void *switch_thread (struct thread_struct *last,
  34                             struct thread_struct *next);
  35 #define switch_to(prev,next,last) do {                                  \
  36         if (prev != next) {                                             \
  37                 (last) = switch_thread (&prev->thread, &next->thread);  \
  38         }                                                               \
  39 } while (0)
  40
  41
  42 /* Enable/disable interrupts.  */
  43 #define __sti() \
  44 {                                                               \
  45         register unsigned tmp;                                  \
  46         __asm__ __volatile__ ("                                 \
  47                         mfs     %0, rmsr;                       \
  48                         ori     %0, %0, 2;                      \
  49                         mts     rmsr, %0"                       \
  50                         : "=r" (tmp)                            \
  51                         :                                       \
  52                         : "memory");                            \
  53 }
  54
  55 #define __cli() \
  56 {                                                               \
  57         register unsigned tmp;                                  \
  58         __asm__ __volatile__ ("                                 \
  59                         mfs     %0, rmsr;                       \
  60                         andi    %0, %0, ~2;                     \
  61                         mts     rmsr, %0"                       \
  62                         : "=r" (tmp)                            \
  63                         :                                       \
  64                         : "memory");                            \
  65 }
  66
  67 #define __save_flags(flags) \
  68         __asm__ __volatile__ ("mfs      %0, rmsr" : "=r" (flags))
  69 #define __restore_flags(flags) \
  70         __asm__ __volatile__ ("mts      rmsr, %0" :: "r" (flags))
  71
  72 #define __save_flags_cli(flags) \
  73 {                                                               \
  74         register unsigned tmp;                                  \
  75         __asm__ __volatile__ ("                                 \
  76                         mfs     %0, rmsr;                       \
  77                         andi    %1, %0, ~2;                     \
  78                         mts     rmsr, %1;"                      \
  79                         : "=r" (flags), "=r" (tmp)              \
  80                         :                                       \
  81                         : "memory");                            \
  82 }
  83
  84 #define __save_flags_sti(flags)                                 \
  85 {                                                               \
  86         register unsigned tmp;                                  \
  87         __asm__ __volatile__ ("                                 \
  88                         mfs     %0, rmsr;                       \
  89                         ori     %1, %0, 2;                      \
  90                         mts     rmsr, %1;"                      \
  91                         : "=r" (flags) ,"=r" (tmp)              \
  92                         :                                       \
  93                         : "memory");                            \
  94 }
  95
  96 /* For spinlocks etc */
  97 #define local_irq_save(flags)   __save_flags_cli (flags)
  98 #define local_irq_set(flags)    __save_flags_sti (flags)
  99 #define local_irq_restore(flags) __restore_flags (flags)
 100 #define local_irq_disable()     __cli ()
 101 #define local_irq_enable()      __sti ()
 102
 103 #define cli()                   __cli ()
 104 #define sti()                   __sti ()
 105 #define save_flags(flags)       __save_flags (flags)
 106 #define restore_flags(flags)    __restore_flags (flags)
 107 #define save_flags_cli(flags)   __save_flags_cli (flags)
 108
 109 /*
 110  * Force strict CPU ordering.
 111  * Not really required on microblaze...
 112  */
 113 #define nop()                   __asm__ __volatile__ ("nop")
 114 #define mb()                    __asm__ __volatile__ ("nop" ::: "memory")
 115 #define rmb()                   mb ()
 116 #define wmb()                   mb ()
 117 #define set_mb(var, value)      do { var = value; mb(); } while (0)
 118 #define set_wmb(var, value)     do { var = value; wmb (); } while (0)
 119
 120 #ifdef CONFIG_SMP
 121 #define smp_mb()        mb ()
 122 #define smp_rmb()       rmb ()
 123 #define smp_wmb()       wmb ()
 124 #else
 125 #define smp_mb()        barrier ()
 126 #define smp_rmb()       barrier ()
 127 #define smp_wmb()       barrier ()
 128 #endif
 129
 130 #define xchg(ptr, with) \
 131   ((__typeof__ (*(ptr)))__xchg ((unsigned long)(with), (ptr), sizeof (*(ptr))))
 132 #define tas(ptr) (xchg ((ptr), 1))
 133
 134 extern inline unsigned long __xchg (unsigned long with,
 135                                     __volatile__ void *ptr, int size)
 136 {
 137         unsigned long tmp, flags;
 138
 139         save_flags_cli (flags);
 140
 141         switch (size) {
 142         case 1:
 143                 tmp = *(unsigned char *)ptr;
 144                 *(unsigned char *)ptr = with;
 145                 break;
 146         case 2:
 147                 tmp = *(unsigned short *)ptr;
 148                 *(unsigned short *)ptr = with;
 149                 break;
 150         case 4:
 151                 tmp = *(unsigned long *)ptr;
 152                 *(unsigned long *)ptr = with;
 153                 break;
 154         }
 155
 156         restore_flags (flags);
 157
 158         return tmp;
 159 }
 160
 161 #endif /* __MICROBLAZE_SYSTEM_H__ */