firmware/target/hosted/android/thread-android-arm.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 by Thom Johansen
  11  * Copyright (C) 2010 by Thomas Martitz (Android-suitable core_sleep())
  12  *
  13  * Generic ARM threading support
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  21  * KIND, either express or implied.
  22  *
  23  ****************************************************************************/
  24
  25 #include <jni.h>
  26 /*---------------------------------------------------------------------------
  27  * Start the thread running and terminate it if it returns
  28  *---------------------------------------------------------------------------
  29  */
  30 static void __attribute__((naked,used)) start_thread(void)
  31 {
  32     /* r0 = context */
  33     asm volatile (
  34         "ldr    sp, [r0, #32]            \n" /* Load initial sp */
  35         "ldr    r4, [r0, #40]            \n" /* start in r4 since it's non-volatile */
  36         "mov    r1, #0                   \n" /* Mark thread as running */
  37         "str    r1, [r0, #40]            \n"
  38         "mov    lr, pc                   \n" /* Call thread function */
  39         "bx     r4                       \n"
  40     ); /* No clobber list - new thread doesn't care */
  41     thread_exit();
  42 }
  43
  44 /* For startup, place context pointer in r4 slot, start_thread pointer in r5
  45  * slot, and thread function pointer in context.start. See load_context for
  46  * what happens when thread is initially going to run. */
  47 #define THREAD_STARTUP_INIT(core, thread, function) \
  48     ({ (thread)->context.r[0] = (uint32_t)&(thread)->context,  \
  49        (thread)->context.r[1] = (uint32_t)start_thread, \
  50        (thread)->context.start = (uint32_t)function; })
  51
  52
  53 /*---------------------------------------------------------------------------
  54  * Store non-volatile context.
  55  *---------------------------------------------------------------------------
  56  */
  57 static inline void store_context(void* addr)
  58 {
  59     asm volatile(
  60         "stmia  %0, { r4-r11, sp, lr } \n"
  61         : : "r" (addr)
  62     );
  63 }
  64
  65 /*---------------------------------------------------------------------------
  66  * Load non-volatile context.
  67  *---------------------------------------------------------------------------
  68  */
  69 static inline void load_context(const void* addr)
  70 {
  71     asm volatile(
  72         "ldr     r0, [%0, #40]          \n" /* Load start pointer */
  73         "cmp     r0, #0                 \n" /* Check for NULL */
  74
  75         /* If not already running, jump to start */
  76         "ldmneia %0, { r0, pc }         \n"
  77         "ldmia   %0, { r4-r11, sp, lr } \n" /* Load regs r4 to r14 from context */
  78         : : "r" (addr) : "r0" /* only! */
  79     );
  80 }
  81
  82 extern JNIEnv *env_ptr;
  83 extern jclass  RockboxActivity_class;
  84 extern jobject RockboxActivity_instance;
  85
  86 /*
  87  * this core sleep suspends the thread rockbox runs under, which greatly
  88  * reduces cpu usage (~100% to <10%)
  89  *
  90  * it returns when the RockboxTimer notified us, i.e. at each tick
  91  **/
  92 static inline void core_sleep(void)
  93 {
  94     static bool got_method_id = false;
  95     static jmethodID java_core_sleep;
  96
  97     if (UNLIKELY(!got_method_id))
  98     {   /* cache method id */
  99        java_core_sleep = (*env_ptr)->GetMethodID(env_ptr,
 100                                                  RockboxActivity_class,
 101                                                  "java_core_sleep",
 102                                                  "()V");
 103         got_method_id = true;
 104     }
 105     (*env_ptr)->CallVoidMethod(env_ptr, RockboxActivity_instance, java_core_sleep);
 106 }
 107
 108