include/asm-v850/system.h

   1 /*
   2  * include/asm-v850/system.h -- Low-level interrupt/thread ops
   3  *
   4  *  Copyright (C) 2001,02,03  NEC Electronics Corporation
   5  *  Copyright (C) 2001,02,03  Miles Bader <miles@gnu.org>
   6  *
   7  * This file is subject to the terms and conditions of the GNU General
   8  * Public License.  See the file COPYING in the main directory of this
   9  * archive for more details.
  10  *
  11  * Written by Miles Bader <miles@gnu.org>
  12  */
  13
  14 #ifndef __V850_SYSTEM_H__
  15 #define __V850_SYSTEM_H__
  16
  17 #include <linux/linkage.h>
  18 #include <asm/ptrace.h>
  19
  20
  21 #define prepare_to_switch()     do { } while (0)
  22
  23 /*
  24  * switch_to(n) should switch tasks to task ptr, first checking that
  25  * ptr isn't the current task, in which case it does nothing.
  26  */
  27 struct thread_struct;
  28 extern void *switch_thread (struct thread_struct *last,
  29                             struct thread_struct *next);
  30 #define switch_to(prev,next,last)                                             \
  31   do {                                                                        \
  32         if (prev != next) {                                                   \
  33                 (last) = switch_thread (&prev->thread, &next->thread);        \
  34         }                                                                     \
  35   } while (0)
  36
  37
  38 /* Enable/disable interrupts.  */
  39 #define local_irq_enable()      __asm__ __volatile__ ("ei")
  40 #define local_irq_disable()     __asm__ __volatile__ ("di")
  41
  42 #define local_save_flags(flags) \
  43   __asm__ __volatile__ ("stsr %1, %0" : "=r" (flags) : "i" (SR_PSW))
  44 #define local_restore_flags(flags) \
  45   __asm__ __volatile__ ("ldsr %0, %1" :: "r" (flags), "i" (SR_PSW))
  46
  47 /* For spinlocks etc */
  48 #define local_irq_save(flags) \
  49   do { local_save_flags (flags); local_irq_disable (); } while (0)
  50 #define local_irq_restore(flags) \
  51   local_restore_flags (flags);
  52
  53
  54 static inline int irqs_disabled (void)
  55 {
  56         unsigned flags;
  57         local_save_flags (flags);
  58         return !!(flags & 0x20);
  59 }
  60
  61
  62 /*
  63  * Force strict CPU ordering.
  64  * Not really required on v850...
  65  */
  66 #define nop()                   __asm__ __volatile__ ("nop")
  67 #define mb()                    __asm__ __volatile__ ("" ::: "memory")
  68 #define rmb()                   mb ()
  69 #define wmb()                   mb ()
  70 #define read_barrier_depends()  ((void)0)
  71 #define set_rmb(var, value)     do { xchg (&var, value); } while (0)
  72 #define set_mb(var, value)      set_rmb (var, value)
  73 #define set_wmb(var, value)     do { var = value; wmb (); } while (0)
  74
  75 #define smp_mb()        mb ()
  76 #define smp_rmb()       rmb ()
  77 #define smp_wmb()       wmb ()
  78 #define smp_read_barrier_depends()      read_barrier_depends()
  79
  80 #define xchg(ptr, with) \
  81   ((__typeof__ (*(ptr)))__xchg ((unsigned long)(with), (ptr), sizeof (*(ptr))))
  82 #define tas(ptr) (xchg ((ptr), 1))
  83
  84 extern inline unsigned long __xchg (unsigned long with,
  85                                     __volatile__ void *ptr, int size)
  86 {
  87         unsigned long tmp, flags;
  88
  89         local_irq_save (flags);
  90
  91         switch (size) {
  92         case 1:
  93                 tmp = *(unsigned char *)ptr;
  94                 *(unsigned char *)ptr = with;
  95                 break;
  96         case 2:
  97                 tmp = *(unsigned short *)ptr;
  98                 *(unsigned short *)ptr = with;
  99                 break;
 100         case 4:
 101                 tmp = *(unsigned long *)ptr;
 102                 *(unsigned long *)ptr = with;
 103                 break;
 104         }
 105
 106         local_irq_restore (flags);
 107
 108         return tmp;
 109 }
 110
 111 #endif /* __V850_SYSTEM_H__ */