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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 by Thom Johansen
* Copyright (C) 2010 by Thomas Martitz (Android-suitable core_sleep())
*
* Generic ARM threading support
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <system.h>
/*---------------------------------------------------------------------------
* Start the thread running and terminate it if it returns
*---------------------------------------------------------------------------
*/
static void __attribute__((naked)) USED_ATTR start_thread(void)
{
/* r0 = context */
asm volatile (
"ldr sp, [r0, #32] \n" /* Load initial sp */
"ldr r4, [r0, #40] \n" /* start in r4 since it's non-volatile */
"mov r1, #0 \n" /* Mark thread as running */
"str r1, [r0, #40] \n"
"mov lr, pc \n" /* Call thread function */
"bx r4 \n"
); /* No clobber list - new thread doesn't care */
thread_exit();
}
/* For startup, place context pointer in r4 slot, start_thread pointer in r5
* slot, and thread function pointer in context.start. See load_context for
* what happens when thread is initially going to run. */
#define THREAD_STARTUP_INIT(core, thread, function) \
({ (thread)->context.r[0] = (uint32_t)&(thread)->context, \
(thread)->context.r[1] = (uint32_t)start_thread, \
(thread)->context.start = (uint32_t)function; })
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile(
"stmia %0, { r4-r11, sp, lr } \n"
: : "r" (addr)
);
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(const void* addr)
{
asm volatile(
"ldr r0, [%0, #40] \n" /* Load start pointer */
"cmp r0, #0 \n" /* Check for NULL */
/* If not already running, jump to start */
"ldmneia %0, { r0, pc } \n"
"ldmia %0, { r4-r11, sp, lr } \n" /* Load regs r4 to r14 from context */
: : "r" (addr) : "r0" /* only! */
);
}
/*
* this core sleep suspends the OS thread rockbox runs under, which greatly
* reduces cpu usage (~100% to <10%)
*
* it returns when when the tick timer is called, other interrupt-like
* events occur
*
* wait_for_interrupt is implemented in kernel-<platform>.c
**/
static inline void core_sleep(void)
{
enable_irq();
wait_for_interrupt();
}
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