include/asm-nios2nommu/system.h

   1 /*
   2  * Taken from the m68k.
   3  *
   4  * Copyright (C) 2004, Microtronix Datacom Ltd.
   5  *
   6  * All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  16  * NON INFRINGEMENT.  See the GNU General Public License for more
  17  * details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  */
  24
  25 #ifndef _NIOS2NOMMU_SYSTEM_H
  26 #define _NIOS2NOMMU_SYSTEM_H
  27
  28 #include <linux/linkage.h>
  29 #include <asm/segment.h>
  30 #include <asm/entry.h>
  31 #include <asm/nios.h>
  32
  33 /*
  34  * switch_to(n) should switch tasks to task ptr, first checking that
  35  * ptr isn't the current task, in which case it does nothing.  This
  36  * also clears the TS-flag if the task we switched to has used the
  37  * math co-processor latest.
  38  */
  39
  40 /*
  41  */
  42 asmlinkage void resume(void);
  43 #define switch_to(prev,next,last)                               \
  44 {                                                               \
  45   void *_last;                                                  \
  46   __asm__ __volatile__(                                         \
  47         "mov    r4, %1\n"                                       \
  48         "mov    r5, %2\n"                                       \
  49         "call   resume\n"                                       \
  50         "mov    %0,r4\n"                                        \
  51        : "=r" (_last)                                           \
  52        : "r" (prev), "r" (next)                                 \
  53        : "r4","r5","r7","r8","ra");     \
  54   (last) = _last;                                               \
  55 }
  56
  57 #define local_irq_enable() __asm__ __volatile__ (  \
  58         "rdctl  r8, status\n"                      \
  59         "ori    r8, r8, 1\n"                       \
  60         "wrctl  status, r8\n"                      \
  61         : : : "r8")
  62
  63 #define local_irq_disable() __asm__ __volatile__ ( \
  64         "rdctl  r8, status\n"                      \
  65         "andi   r8, r8, 0xfffe\n"                  \
  66         "wrctl  status, r8\n"                      \
  67         : : : "r8")
  68
  69 #define local_save_flags(x) __asm__ __volatile__ (      \
  70         "rdctl  r8, status\n"                           \
  71         "mov    %0, r8\n"                               \
  72         :"=r" (x) : : "r8", "memory")
  73
  74 #define local_irq_restore(x) __asm__ __volatile__ (     \
  75         "mov    r8, %0\n"                               \
  76         "wrctl  status, r8\n"                           \
  77         : :"r" (x) : "memory")
  78
  79 /* For spinlocks etc */
  80 #define local_irq_save(x) do { local_save_flags(x); local_irq_disable(); } while (0)
  81
  82 #define irqs_disabled()                                 \
  83 ({                                                      \
  84         unsigned long flags;                            \
  85         local_save_flags(flags);                        \
  86         ((flags & NIOS2_STATUS_PIE_MSK) == 0x0);        \
  87 })
  88
  89 #define iret() __asm__ __volatile__ ("eret": : :"memory", "ea")
  90
  91 /*
  92  * Force strict CPU ordering.
  93  * Not really required on m68k...
  94  */
  95 #define nop()  asm volatile ("nop"::)
  96 #define mb()   asm volatile (""   : : :"memory")
  97 #define rmb()  asm volatile (""   : : :"memory")
  98 #define wmb()  asm volatile (""   : : :"memory")
  99 #define set_rmb(var, value)    do { xchg(&var, value); } while (0)
 100 #define set_mb(var, value)     set_rmb(var, value)
 101 #define set_wmb(var, value)    do { var = value; wmb(); } while (0)
 102
 103 #ifdef CONFIG_SMP
 104 #define smp_mb()        mb()
 105 #define smp_rmb()       rmb()
 106 #define smp_wmb()       wmb()
 107 #define smp_read_barrier_depends()      read_barrier_depends()
 108 #else
 109 #define smp_mb()        barrier()
 110 #define smp_rmb()       barrier()
 111 #define smp_wmb()       barrier()
 112 #define smp_read_barrier_depends()      do { } while(0)
 113 #endif
 114
 115 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 116 #define tas(ptr) (xchg((ptr),1))
 117
 118 struct __xchg_dummy { unsigned long a[100]; };
 119 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
 120
 121 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 122 {
 123   unsigned long tmp, flags;
 124
 125   local_irq_save(flags);
 126
 127   switch (size) {
 128   case 1:
 129     __asm__ __volatile__( \
 130       "ldb      %0, %2\n" \
 131       "stb      %1, %2\n" \
 132     : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
 133     break;
 134   case 2:
 135     __asm__ __volatile__( \
 136       "ldh      %0, %2\n" \
 137       "sth      %1, %2\n" \
 138     : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
 139     break;
 140   case 4:
 141     __asm__ __volatile__( \
 142       "ldw      %0, %2\n" \
 143       "stw      %1, %2\n" \
 144     : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
 145     break;
 146   }
 147   local_irq_restore(flags);
 148   return tmp;
 149 }
 150
 151 /*
 152  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
 153  * store NEW in MEM.  Return the initial value in MEM.  Success is
 154  * indicated by comparing RETURN with OLD.
 155  */
 156 #define __HAVE_ARCH_CMPXCHG     1
 157
 158 static __inline__ unsigned long
 159 cmpxchg(volatile int *p, int old, int new)
 160 {
 161         unsigned long flags;
 162         int prev;
 163
 164         local_irq_save(flags);
 165         if ((prev = *p) == old)
 166                 *p = new;
 167         local_irq_restore(flags);
 168         return(prev);
 169 }
 170
 171 #endif /* _NIOS2NOMMU_SYSTEM_H */