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 /*
  22  * switch_to(n) should switch tasks to task ptr, first checking that
  23  * ptr isn't the current task, in which case it does nothing.
  24  */
  25 struct thread_struct;
  26 extern void *switch_thread (struct thread_struct *last,
  27                             struct thread_struct *next);
  28 #define switch_to(prev,next,last)                                             \
  29   do {                                                                        \
  30         if (prev != next) {                                                   \
  31                 (last) = switch_thread (&prev->thread, &next->thread);        \
  32         }                                                                     \
  33   } while (0)
  34
  35
  36 /* Enable/disable interrupts.  */
  37 #define local_irq_enable()      __asm__ __volatile__ ("ei")
  38 #define local_irq_disable()     __asm__ __volatile__ ("di")
  39
  40 #define local_save_flags(flags) \
  41   __asm__ __volatile__ ("stsr %1, %0" : "=r" (flags) : "i" (SR_PSW))
  42 #define local_restore_flags(flags) \
  43   __asm__ __volatile__ ("ldsr %0, %1" :: "r" (flags), "i" (SR_PSW))
  44
  45 /* For spinlocks etc */
  46 #define local_irq_save(flags) \
  47   do { local_save_flags (flags); local_irq_disable (); } while (0)
  48 #define local_irq_restore(flags) \
  49   local_restore_flags (flags);
  50
  51
  52 static inline int irqs_disabled (void)
  53 {
  54         unsigned flags;
  55         local_save_flags (flags);
  56         return !!(flags & 0x20);
  57 }
  58
  59
  60 /*
  61  * Force strict CPU ordering.
  62  * Not really required on v850...
  63  */
  64 #define nop()                   __asm__ __volatile__ ("nop")
  65 #define mb()                    __asm__ __volatile__ ("" ::: "memory")
  66 #define rmb()                   mb ()
  67 #define wmb()                   mb ()
  68 #define read_barrier_depends()  ((void)0)
  69 #define set_rmb(var, value)     do { xchg (&var, value); } while (0)
  70 #define set_mb(var, value)      set_rmb (var, value)
  71
  72 #define smp_mb()        mb ()
  73 #define smp_rmb()       rmb ()
  74 #define smp_wmb()       wmb ()
  75 #define smp_read_barrier_depends()      read_barrier_depends()
  76
  77 #define xchg(ptr, with) \
  78   ((__typeof__ (*(ptr)))__xchg ((unsigned long)(with), (ptr), sizeof (*(ptr))))
  79 #define tas(ptr) (xchg ((ptr), 1))
  80
  81 static inline unsigned long __xchg (unsigned long with,
  82                                     __volatile__ void *ptr, int size)
  83 {
  84         unsigned long tmp, flags;
  85
  86         local_irq_save (flags);
  87
  88         switch (size) {
  89         case 1:
  90                 tmp = *(unsigned char *)ptr;
  91                 *(unsigned char *)ptr = with;
  92                 break;
  93         case 2:
  94                 tmp = *(unsigned short *)ptr;
  95                 *(unsigned short *)ptr = with;
  96                 break;
  97         case 4:
  98                 tmp = *(unsigned long *)ptr;
  99                 *(unsigned long *)ptr = with;
 100                 break;
 101         }
 102
 103         local_irq_restore (flags);
 104
 105         return tmp;
 106 }
 107
 108 #define arch_align_stack(x) (x)
 109
 110 #endif /* __V850_SYSTEM_H__ */