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   1 /*
   2  * File:        include/asm/system.h
   3  * Based on:
   4  * Author:      Tony Kou (tonyko@lineo.ca)
   5  *              Copyright (c) 2002 Arcturus Networks Inc.
   6  *                    (www.arcturusnetworks.com)
   7  *              Copyright (c) 2003 Metrowerks (www.metrowerks.com)
   8  *              Copyright (c) 2004 Analog Device Inc.
   9  * Created:     25Jan2001 - Tony Kou
  10  * Description: system.h include file
  11  *
  12  * Modified:     22Sep2006 - Robin Getz
  13  *                - move include blackfin.h down, so I can get access to
  14  *                   irq functions in other include files.
  15  *
  16  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  17  *
  18  * This program is free software; you can redistribute it and/or modify
  19  * it under the terms of the GNU General Public License as published by
  20  * the Free Software Foundation; either version 2, or (at your option)
  21  * any later version.
  22  *
  23  * This program is distributed in the hope that it will be useful,
  24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  * GNU General Public License for more details.
  27  *
  28  * You should have received a copy of the GNU General Public License
  29  * along with this program; see the file COPYING.
  30  * If not, write to the Free Software Foundation,
  31  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  32  */
  33
  34 #ifndef _BLACKFIN_SYSTEM_H
  35 #define _BLACKFIN_SYSTEM_H
  36
  37 #include <linux/linkage.h>
  38 #include <linux/compiler.h>
  39
  40 /*
  41  * Interrupt configuring macros.
  42  */
  43
  44 extern unsigned long irq_flags;
  45
  46 #define local_irq_enable() do {         \
  47         __asm__ __volatile__ (          \
  48                 "sti %0;"               \
  49                 ::"d"(irq_flags));      \
  50 } while (0)
  51
  52 #define local_irq_disable() do {        \
  53         int _tmp_dummy;                 \
  54         __asm__ __volatile__ (          \
  55                 "cli %0;"               \
  56                 :"=d" (_tmp_dummy):);   \
  57 } while (0)
  58
  59 #if defined(ANOMALY_05000244) && defined (CONFIG_BLKFIN_CACHE)
  60 #define idle_with_irq_disabled() do {   \
  61         __asm__ __volatile__ (          \
  62                 "nop; nop;\n"           \
  63                 ".align 8;\n"           \
  64                 "sti %0; idle;\n"       \
  65                 ::"d" (irq_flags));     \
  66 } while (0)
  67 #else
  68 #define idle_with_irq_disabled() do {   \
  69         __asm__ __volatile__ (          \
  70                 ".align 8;\n"           \
  71                 "sti %0; idle;\n"       \
  72                 ::"d" (irq_flags));     \
  73 } while (0)
  74 #endif
  75
  76 #ifdef CONFIG_DEBUG_HWERR
  77 #define __save_and_cli(x) do {                  \
  78         __asm__ __volatile__ (                  \
  79                 "cli %0;\n\tsti %1;"            \
  80                 :"=&d"(x): "d" (0x3F));         \
  81 } while (0)
  82 #else
  83 #define __save_and_cli(x) do {          \
  84         __asm__ __volatile__ (          \
  85                 "cli %0;"               \
  86                 :"=&d"(x):);            \
  87 } while (0)
  88 #endif
  89
  90 #define local_save_flags(x) asm volatile ("cli %0;"     \
  91                                           "sti %0;"     \
  92                                           :"=d"(x):);
  93
  94 #ifdef CONFIG_DEBUG_HWERR
  95 #define irqs_enabled_from_flags(x) (((x) & ~0x3f) != 0)
  96 #else
  97 #define irqs_enabled_from_flags(x) ((x) != 0x1f)
  98 #endif
  99
 100 #define local_irq_restore(x) do {                       \
 101         if (irqs_enabled_from_flags(x))                 \
 102                 local_irq_enable ();                    \
 103 } while (0)
 104
 105 /* For spinlocks etc */
 106 #define local_irq_save(x) __save_and_cli(x)
 107
 108 #define irqs_disabled()                         \
 109 ({                                              \
 110         unsigned long flags;                    \
 111         local_save_flags(flags);                \
 112         !irqs_enabled_from_flags(flags);        \
 113 })
 114
 115 /*
 116  * Force strict CPU ordering.
 117  */
 118 #define nop()  asm volatile ("nop;\n\t"::)
 119 #define mb()   asm volatile (""   : : :"memory")
 120 #define rmb()  asm volatile (""   : : :"memory")
 121 #define wmb()  asm volatile (""   : : :"memory")
 122 #define set_rmb(var, value)    do { (void) xchg(&var, value); } while (0)
 123 #define set_mb(var, value)     set_rmb(var, value)
 124 #define set_wmb(var, value)    do { var = value; wmb(); } while (0)
 125
 126 #define read_barrier_depends()          do { } while(0)
 127
 128 #ifdef CONFIG_SMP
 129 #define smp_mb()        mb()
 130 #define smp_rmb()       rmb()
 131 #define smp_wmb()       wmb()
 132 #define smp_read_barrier_depends()      read_barrier_depends()
 133 #else
 134 #define smp_mb()        barrier()
 135 #define smp_rmb()       barrier()
 136 #define smp_wmb()       barrier()
 137 #define smp_read_barrier_depends()      do { } while(0)
 138 #endif
 139
 140 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 141 #define tas(ptr) ((void)xchg((ptr),1))
 142
 143 struct __xchg_dummy {
 144         unsigned long a[100];
 145 };
 146 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
 147
 148 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
 149                                    int size)
 150 {
 151         unsigned long tmp = 0;
 152         unsigned long flags = 0;
 153
 154         local_irq_save(flags);
 155
 156         switch (size) {
 157         case 1:
 158                 __asm__ __volatile__
 159                         ("%0 = b%2 (z);\n\t"
 160                          "b%2 = %1;\n\t"
 161                          : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 162                 break;
 163         case 2:
 164                 __asm__ __volatile__
 165                         ("%0 = w%2 (z);\n\t"
 166                          "w%2 = %1;\n\t"
 167                          : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 168                 break;
 169         case 4:
 170                 __asm__ __volatile__
 171                         ("%0 = %2;\n\t"
 172                          "%2 = %1;\n\t"
 173                          : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 174                 break;
 175         }
 176         local_irq_restore(flags);
 177         return tmp;
 178 }
 179
 180 /*
 181  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
 182  * store NEW in MEM.  Return the initial value in MEM.  Success is
 183  * indicated by comparing RETURN with OLD.
 184  */
 185 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 186                                       unsigned long new, int size)
 187 {
 188         unsigned long tmp = 0;
 189         unsigned long flags = 0;
 190
 191         local_irq_save(flags);
 192
 193         switch (size) {
 194         case 1:
 195                 __asm__ __volatile__
 196                         ("%0 = b%3 (z);\n\t"
 197                          "CC = %1 == %0;\n\t"
 198                          "IF !CC JUMP 1f;\n\t"
 199                          "b%3 = %2;\n\t"
 200                          "1:\n\t"
 201                          : "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");
 202                 break;
 203         case 2:
 204                 __asm__ __volatile__
 205                         ("%0 = w%3 (z);\n\t"
 206                          "CC = %1 == %0;\n\t"
 207                          "IF !CC JUMP 1f;\n\t"
 208                          "w%3 = %2;\n\t"
 209                          "1:\n\t"
 210                          : "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");
 211                 break;
 212         case 4:
 213                 __asm__ __volatile__
 214                         ("%0 = %3;\n\t"
 215                          "CC = %1 == %0;\n\t"
 216                          "IF !CC JUMP 1f;\n\t"
 217                          "%3 = %2;\n\t"
 218                          "1:\n\t"
 219                          : "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");
 220                 break;
 221         }
 222         local_irq_restore(flags);
 223         return tmp;
 224 }
 225
 226 #define cmpxchg(ptr,o,n)\
 227         ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
 228                                         (unsigned long)(n),sizeof(*(ptr))))
 229
 230 #define prepare_to_switch()     do { } while(0)
 231
 232 /*
 233  * switch_to(n) should switch tasks to task ptr, first checking that
 234  * ptr isn't the current task, in which case it does nothing.
 235  */
 236
 237 #include <asm/blackfin.h>
 238
 239 asmlinkage struct task_struct *resume(struct task_struct *prev, struct task_struct *next);
 240
 241 #define switch_to(prev,next,last) \
 242 do {    \
 243         memcpy (&prev->thread_info->l1_task_info, L1_SCRATCH_TASK_INFO, \
 244                 sizeof *L1_SCRATCH_TASK_INFO); \
 245         memcpy (L1_SCRATCH_TASK_INFO, &next->thread_info->l1_task_info, \
 246                 sizeof *L1_SCRATCH_TASK_INFO); \
 247         (last) = resume (prev, next);   \
 248 } while (0)
 249
 250 #endif                          /* _BLACKFIN_SYSTEM_H */