include/asm-arm26/locks.h

   1 /*
   2  *  linux/include/asm-arm/proc-armo/locks.h
   3  *
   4  *  Copyright (C) 2000 Russell King
   5  *  Fixes for 26 bit machines, (C) 2000 Dave Gilbert
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  *  Interrupt safe locking assembler.
  12  */
  13 #ifndef __ASM_PROC_LOCKS_H
  14 #define __ASM_PROC_LOCKS_H
  15
  16 /* Decrements by 1, fails if value < 0 */
  17 #define __down_op(ptr,fail)                     \
  18         ({                                      \
  19         __asm__ __volatile__ (                  \
  20         "@ atomic down operation\n"             \
  21 "       mov     ip, pc\n"                       \
  22 "       orr     lr, ip, #0x08000000\n"          \
  23 "       teqp    lr, #0\n"                       \
  24 "       ldr     lr, [%0]\n"                     \
  25 "       and     ip, ip, #0x0c000003\n"          \
  26 "       subs    lr, lr, #1\n"                   \
  27 "       str     lr, [%0]\n"                     \
  28 "       orrmi   ip, ip, #0x80000000     @ set N\n" \
  29 "       teqp    ip, #0\n"                       \
  30 "       movmi   ip, %0\n"                       \
  31 "       blmi    " #fail                         \
  32         :                                       \
  33         : "r" (ptr)                             \
  34         : "ip", "lr", "cc");                    \
  35         })
  36
  37 #define __down_op_ret(ptr,fail)                 \
  38         ({                                      \
  39                 unsigned int result;            \
  40         __asm__ __volatile__ (                  \
  41 "       @ down_op_ret\n"                        \
  42 "       mov     ip, pc\n"                       \
  43 "       orr     lr, ip, #0x08000000\n"          \
  44 "       teqp    lr, #0\n"                       \
  45 "       ldr     lr, [%1]\n"                     \
  46 "       and     ip, ip, #0x0c000003\n"          \
  47 "       subs    lr, lr, #1\n"                   \
  48 "       str     lr, [%1]\n"                     \
  49 "       orrmi   ip, ip, #0x80000000     @ set N\n" \
  50 "       teqp    ip, #0\n"                       \
  51 "       movmi   ip, %1\n"                       \
  52 "       movpl   ip, #0\n"                       \
  53 "       blmi    " #fail "\n"                    \
  54 "       mov     %0, ip"                         \
  55         : "=&r" (result)                        \
  56         : "r" (ptr)                             \
  57         : "ip", "lr", "cc");                    \
  58         result;                                 \
  59         })
  60
  61 #define __up_op(ptr,wake)                       \
  62         ({                                      \
  63         __asm__ __volatile__ (                  \
  64         "@ up_op\n"                             \
  65 "       mov     ip, pc\n"                       \
  66 "       orr     lr, ip, #0x08000000\n"          \
  67 "       teqp    lr, #0\n"                       \
  68 "       ldr     lr, [%0]\n"                     \
  69 "       and     ip, ip, #0x0c000003\n"          \
  70 "       adds    lr, lr, #1\n"                   \
  71 "       str     lr, [%0]\n"                     \
  72 "       orrle   ip, ip, #0x80000000     @ set N - should this be mi ??? DAG ! \n" \
  73 "       teqp    ip, #0\n"                       \
  74 "       movmi   ip, %0\n"                       \
  75 "       blmi    " #wake                         \
  76         :                                       \
  77         : "r" (ptr)                             \
  78         : "ip", "lr", "cc");                    \
  79         })
  80
  81 /*
  82  * The value 0x01000000 supports up to 128 processors and
  83  * lots of processes.  BIAS must be chosen such that sub'ing
  84  * BIAS once per CPU will result in the long remaining
  85  * negative.
  86  */
  87 #define RW_LOCK_BIAS      0x01000000
  88 #define RW_LOCK_BIAS_STR "0x01000000"
  89
  90 /* Decrements by RW_LOCK_BIAS rather than 1, fails if value != 0 */
  91 #define __down_op_write(ptr,fail)               \
  92         ({                                      \
  93         __asm__ __volatile__(                   \
  94         "@ down_op_write\n"                     \
  95 "       mov     ip, pc\n"                       \
  96 "       orr     lr, ip, #0x08000000\n"          \
  97 "       teqp    lr, #0\n"                       \
  98 "       and     ip, ip, #0x0c000003\n"          \
  99 \
 100 "       ldr     lr, [%0]\n"                     \
 101 "       subs    lr, lr, %1\n"                   \
 102 "       str     lr, [%0]\n"                     \
 103 \
 104 " orreq ip, ip, #0x40000000 @ set Z \n"\
 105 "       teqp    ip, #0\n"                       \
 106 "       movne   ip, %0\n"                       \
 107 "       blne    " #fail                         \
 108         :                                       \
 109         : "r" (ptr), "I" (RW_LOCK_BIAS)         \
 110         : "ip", "lr", "cc");                    \
 111         })
 112
 113 /* Increments by RW_LOCK_BIAS, wakes if value >= 0 */
 114 #define __up_op_write(ptr,wake)                 \
 115         ({                                      \
 116         __asm__ __volatile__(                   \
 117         "@ up_op_read\n"                        \
 118 "       mov     ip, pc\n"                       \
 119 "       orr     lr, ip, #0x08000000\n"          \
 120 "       teqp    lr, #0\n"                       \
 121 \
 122 "       ldr     lr, [%0]\n"                     \
 123 "       and     ip, ip, #0x0c000003\n"          \
 124 "       adds    lr, lr, %1\n"                   \
 125 "       str     lr, [%0]\n"                     \
 126 \
 127 " orrcs ip, ip, #0x20000000 @ set C\n" \
 128 "       teqp    ip, #0\n"                       \
 129 "       movcs   ip, %0\n"                       \
 130 "       blcs    " #wake                         \
 131         :                                       \
 132         : "r" (ptr), "I" (RW_LOCK_BIAS)         \
 133         : "ip", "lr", "cc");                    \
 134         })
 135
 136 #define __down_op_read(ptr,fail)                \
 137         __down_op(ptr, fail)
 138
 139 #define __up_op_read(ptr,wake)                  \
 140         ({                                      \
 141         __asm__ __volatile__(                   \
 142         "@ up_op_read\n"                        \
 143 "       mov     ip, pc\n"                       \
 144 "       orr     lr, ip, #0x08000000\n"          \
 145 "       teqp    lr, #0\n"                       \
 146 \
 147 "       ldr     lr, [%0]\n"                     \
 148 "       and     ip, ip, #0x0c000003\n"          \
 149 "       adds    lr, lr, %1\n"                   \
 150 "       str     lr, [%0]\n"                     \
 151 \
 152 " orreq ip, ip, #0x40000000 @ Set Z \n" \
 153 "       teqp    ip, #0\n"                       \
 154 "       moveq   ip, %0\n"                       \
 155 "       bleq    " #wake                         \
 156         :                                       \
 157         : "r" (ptr), "I" (1)                    \
 158         : "ip", "lr", "cc");                    \
 159         })
 160
 161 #endif