firmware/target/mips/thread-mips32.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2008 by Maurus Cuelenaere
  11  *
  12  * 32-bit MIPS threading support
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23
  24 /*---------------------------------------------------------------------------
  25  * Start the thread running and terminate it if it returns
  26  *---------------------------------------------------------------------------
  27  */
  28
  29 void start_thread(void); /* Provide C access to ASM label */
  30 static void __attribute__((used)) _start_thread(void)
  31 {
  32     /* t1 = context */
  33     asm volatile (
  34       "start_thread:          \n"
  35         ".set noreorder       \n"
  36         ".set noat            \n"
  37         "lw     $8,    4($9)  \n" /* Fetch thread function pointer ($8 = t0, $9 = t1) */
  38         "lw     $29,  36($9)  \n" /* Set initial sp(=$29) */
  39         "jalr   $8            \n" /* Start the thread */
  40         "sw     $0,   44($9)  \n" /* Clear start address */
  41         ".set at              \n"
  42         ".set reorder         \n"
  43     );
  44     thread_exit();
  45 }
  46
  47 /* Place context pointer in s0 slot, function pointer in s1 slot, and
  48  * start_thread pointer in context_start */
  49 #define THREAD_STARTUP_INIT(core, thread, function)            \
  50     ({ (thread)->context.r[0]  = (uint32_t)&(thread)->context, \
  51        (thread)->context.r[1]  = (uint32_t)(function),         \
  52        (thread)->context.start = (uint32_t)start_thread; })
  53
  54 /*---------------------------------------------------------------------------
  55  * Store non-volatile context.
  56  *---------------------------------------------------------------------------
  57  */
  58 static inline void store_context(void* addr)
  59 {
  60     asm volatile (
  61         ".set noreorder        \n"
  62         ".set noat             \n"
  63         "sw    $16,  0(%0)     \n" /* s0 */
  64         "sw    $17,  4(%0)     \n" /* s1 */
  65         "sw    $18,  8(%0)     \n" /* s2 */
  66         "sw    $19, 12(%0)     \n" /* s3 */
  67         "sw    $20, 16(%0)     \n" /* s4 */
  68         "sw    $21, 20(%0)     \n" /* s5 */
  69         "sw    $22, 24(%0)     \n" /* s6 */
  70         "sw    $23, 28(%0)     \n" /* s7 */
  71         "sw    $30, 32(%0)     \n" /* fp */
  72         "sw    $29, 36(%0)     \n" /* sp */
  73         "sw    $31, 40(%0)     \n" /* ra */
  74         ".set at               \n"
  75         ".set reorder          \n"
  76         : : "r" (addr)
  77     );
  78 }
  79
  80 /*---------------------------------------------------------------------------
  81  * Load non-volatile context.
  82  *---------------------------------------------------------------------------
  83  */
  84 static inline void load_context(const void* addr)
  85 {
  86     asm volatile (
  87         ".set noat             \n"
  88         ".set noreorder        \n"
  89         "lw    $8, 44(%0)      \n" /* Get start address ($8 = t0) */
  90         "beqz  $8, running     \n" /* NULL -> already running */
  91         "nop                   \n"
  92         "jr    $8              \n"
  93         "move  $9, %0          \n" /* t1 = context */
  94     "running:                  \n"
  95         "lw    $16,  0(%0)     \n" /* s0 */
  96         "lw    $17,  4(%0)     \n" /* s1 */
  97         "lw    $18,  8(%0)     \n" /* s2 */
  98         "lw    $19, 12(%0)     \n" /* s3 */
  99         "lw    $20, 16(%0)     \n" /* s4 */
 100         "lw    $21, 20(%0)     \n" /* s5 */
 101         "lw    $22, 24(%0)     \n" /* s6 */
 102         "lw    $23, 28(%0)     \n" /* s7 */
 103         "lw    $30, 32(%0)     \n" /* fp */
 104         "lw    $29, 36(%0)     \n" /* sp */
 105         "lw    $31, 40(%0)     \n" /* ra */
 106         ".set at               \n"
 107         ".set reorder          \n"
 108         : : "r" (addr) : "t0", "t1"
 109     );
 110 }
 111
 112 /*---------------------------------------------------------------------------
 113  * Put core in a power-saving state.
 114  *---------------------------------------------------------------------------
 115  */
 116 static inline void core_sleep(void)
 117 {
 118 #if CONFIG_CPU == JZ4732
 119     __cpm_idle_mode();
 120 #endif
 121     asm volatile(".set   mips32r2           \n"
 122                  "mfc0   $8, $12            \n" /* mfc t0, $12 */
 123                  "move   $9, $8             \n" /* move t1, t0 */
 124                  "la     $10, 0x8000000     \n" /* la t2, 0x8000000 */
 125                  "or     $8, $8, $10        \n" /* Enable reduced power mode */
 126                  "mtc0   $8, $12            \n" /* mtc t0, $12 */
 127                  "wait                      \n"
 128                  "mtc0   $9, $12            \n" /* mtc t1, $12 */
 129                  ".set   mips0              \n"
 130                  ::: "t0", "t1", "t2"
 131                  );
 132     enable_irq();
 133 }