4ce3eb2453
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18895 a1c6a512-1295-4272-9138-f99709370657
155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Felix Arends
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include <stdlib.h>
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#include <SDL.h>
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#include <SDL_thread.h>
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#include "memory.h"
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#include "system-sdl.h"
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#include "uisdl.h"
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#include "kernel.h"
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#include "thread-sdl.h"
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#include "thread.h"
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#include "debug.h"
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static SDL_TimerID tick_timer_id;
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long start_tick;
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/* Condition to signal that "interrupts" may proceed */
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static SDL_cond *sim_thread_cond;
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/* Mutex to serialize changing levels and exclude other threads while
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* inside a handler */
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static SDL_mutex *sim_irq_mtx;
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static int interrupt_level = HIGHEST_IRQ_LEVEL;
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static int handlers_pending = 0;
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static int status_reg = 0;
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/* Nescessary logic:
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* 1) All threads must pass unblocked
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* 2) Current handler must always pass unblocked
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* 3) Threads must be excluded when irq routine is running
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* 4) No more than one handler routine should execute at a time
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*/
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int set_irq_level(int level)
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{
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SDL_LockMutex(sim_irq_mtx);
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int oldlevel = interrupt_level;
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if (status_reg == 0 && level == 0 && oldlevel != 0)
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{
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/* Not in a handler and "interrupts" are being reenabled */
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if (handlers_pending > 0)
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SDL_CondSignal(sim_thread_cond);
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}
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interrupt_level = level; /* save new level */
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SDL_UnlockMutex(sim_irq_mtx);
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return oldlevel;
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}
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void sim_enter_irq_handler(void)
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{
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SDL_LockMutex(sim_irq_mtx);
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handlers_pending++;
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if(interrupt_level != 0)
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{
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/* "Interrupts" are disabled. Wait for reenable */
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SDL_CondWait(sim_thread_cond, sim_irq_mtx);
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}
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status_reg = 1;
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}
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void sim_exit_irq_handler(void)
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{
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if (--handlers_pending > 0)
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SDL_CondSignal(sim_thread_cond);
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status_reg = 0;
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SDL_UnlockMutex(sim_irq_mtx);
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}
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bool sim_kernel_init(void)
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{
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sim_irq_mtx = SDL_CreateMutex();
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if (sim_irq_mtx == NULL)
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{
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fprintf(stderr, "Cannot create sim_handler_mtx\n");
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return false;
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}
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sim_thread_cond = SDL_CreateCond();
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if (sim_thread_cond == NULL)
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{
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fprintf(stderr, "Cannot create sim_thread_cond\n");
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return false;
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}
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return true;
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}
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void sim_kernel_shutdown(void)
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{
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SDL_RemoveTimer(tick_timer_id);
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SDL_DestroyMutex(sim_irq_mtx);
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SDL_DestroyCond(sim_thread_cond);
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}
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Uint32 tick_timer(Uint32 interval, void *param)
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{
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long new_tick;
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(void) interval;
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(void) param;
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new_tick = (SDL_GetTicks() - start_tick) / (1000/HZ);
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while(new_tick != current_tick)
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{
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sim_enter_irq_handler();
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/* Run through the list of tick tasks - increments tick
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* on each iteration. */
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call_tick_tasks();
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sim_exit_irq_handler();
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}
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return 1;
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}
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void tick_start(unsigned int interval_in_ms)
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{
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if (tick_timer_id != NULL)
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{
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SDL_RemoveTimer(tick_timer_id);
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tick_timer_id = NULL;
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}
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else
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{
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start_tick = SDL_GetTicks();
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}
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tick_timer_id = SDL_AddTimer(interval_in_ms, tick_timer, NULL);
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}
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