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rockbox/firmware/target/hosted/sdl/thread-sdl.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 Dan Everton
*
* 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 <stdbool.h>
#include <time.h>
#include <SDL.h>
#include <SDL_thread.h>
#include <stdlib.h>
#include <string.h> /* memset() */
#include <setjmp.h>
#include "system-sdl.h"
#include "thread-sdl.h"
#include "../kernel-internal.h"
#include "core_alloc.h"
/* Define this as 1 to show informational messages that are not errors. */
#define THREAD_SDL_DEBUGF_ENABLED 1
#if THREAD_SDL_DEBUGF_ENABLED
#define THREAD_SDL_DEBUGF(...) DEBUGF(__VA_ARGS__)
static char __name[sizeof (((struct thread_debug_info *)0)->name)];
#define THREAD_SDL_GET_NAME(thread) \
({ format_thread_name(__name, sizeof (__name), thread); __name; })
#else
#define THREAD_SDL_DEBUGF(...)
#define THREAD_SDL_GET_NAME(thread)
#endif
#define THREAD_PANICF(str...) \
({ fprintf(stderr, str); exit(-1); })
/* Jump buffers for graceful exit - kernel threads don't stay neatly
* in their start routines responding to messages so this is the only
* way to get them back in there so they may exit */
static jmp_buf thread_jmpbufs[MAXTHREADS];
/* this mutex locks out other Rockbox threads while one runs,
* that enables us to simulate a cooperative environment even if
* the host is preemptive */
static SDL_mutex *m;
#define THREADS_RUN 0
#define THREADS_EXIT 1
#define THREADS_EXIT_COMMAND_DONE 2
static volatile int threads_status = THREADS_RUN;
extern long start_tick;
void sim_thread_shutdown(void)
{
int i;
/* This *has* to be a push operation from a thread not in the pool
so that they may be dislodged from their blocking calls. */
/* Tell all threads jump back to their start routines, unlock and exit
gracefully - we'll check each one in turn for it's status. Threads
_could_ terminate via thread_exit or multiple threads could exit
on each unlock but that is safe. */
/* Do this before trying to acquire lock */
threads_status = THREADS_EXIT;
/* Take control */
SDL_LockMutex(m);
/* Signal all threads on delay or block */
for (i = 0; i < MAXTHREADS; i++)
{
struct thread_entry *thread = __thread_slot_entry(i);
if (thread->context.s == NULL)
continue;
SDL_SemPost(thread->context.s);
}
/* Wait for all threads to finish and cleanup old ones. */
for (i = 0; i < MAXTHREADS; i++)
{
struct thread_entry *thread = __thread_slot_entry(i);
SDL_Thread *t = thread->context.t;
if (t != NULL)
{
SDL_UnlockMutex(m);
/* Wait for it to finish */
SDL_WaitThread(t, NULL);
/* Relock for next thread signal */
SDL_LockMutex(m);
/* Already waited and exiting thread would have waited .told,
* replacing it with t. */
thread->context.told = NULL;
}
else
{
/* Wait on any previous thread in this location-- could be one not
* quite finished exiting but has just unlocked the mutex. If it's
* NULL, the call returns immediately.
*
* See thread_exit below for more information. */
SDL_WaitThread(thread->context.told, NULL);
}
}
SDL_UnlockMutex(m);
/* Signal completion of operation */
threads_status = THREADS_EXIT_COMMAND_DONE;
}
void sim_thread_exception_wait(void)
{
while (1)
{
SDL_Delay(HZ/10);
if (threads_status != THREADS_RUN)
thread_exit();
}
}
/* A way to yield and leave the threading system for extended periods */
void sim_thread_lock(void *me)
{
SDL_LockMutex(m);
__running_self_entry() = (struct thread_entry *)me;
if (threads_status != THREADS_RUN)
thread_exit();
}
void * sim_thread_unlock(void)
{
struct thread_entry *current = __running_self_entry();
SDL_UnlockMutex(m);
return current;
}
void switch_thread(void)
{
struct thread_entry *current = __running_self_entry();
enable_irq();
switch (current->state)
{
case STATE_RUNNING:
{
SDL_UnlockMutex(m);
/* Any other thread waiting already will get it first */
SDL_LockMutex(m);
break;
} /* STATE_RUNNING: */
case STATE_BLOCKED:
{
int oldlevel;
SDL_UnlockMutex(m);
SDL_SemWait(current->context.s);
SDL_LockMutex(m);
oldlevel = disable_irq_save();
current->state = STATE_RUNNING;
restore_irq(oldlevel);
break;
} /* STATE_BLOCKED: */
case STATE_BLOCKED_W_TMO:
{
int result, oldlevel;
SDL_UnlockMutex(m);
result = SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
SDL_LockMutex(m);
oldlevel = disable_irq_save();
current->state = STATE_RUNNING;
if (result == SDL_MUTEX_TIMEDOUT)
{
/* Other signals from an explicit wake could have been made before
* arriving here if we timed out waiting for the semaphore. Make
* sure the count is reset. */
while (SDL_SemValue(current->context.s) > 0)
SDL_SemTryWait(current->context.s);
}
restore_irq(oldlevel);
break;
} /* STATE_BLOCKED_W_TMO: */
case STATE_SLEEPING:
{
SDL_UnlockMutex(m);
SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
SDL_LockMutex(m);
current->state = STATE_RUNNING;
break;
} /* STATE_SLEEPING: */
}
#ifdef DEBUG
core_check_valid();
#endif
__running_self_entry() = current;
if (threads_status != THREADS_RUN)
thread_exit();
}
void sleep_thread(int ticks)
{
struct thread_entry *current = __running_self_entry();
int rem;
current->state = STATE_SLEEPING;
rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
if (rem < 0)
rem = 0;
current->tmo_tick = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
}
void block_thread_(struct thread_entry *current, int ticks)
{
if (ticks < 0)
current->state = STATE_BLOCKED;
else
{
current->state = STATE_BLOCKED_W_TMO;
current->tmo_tick = (1000/HZ)*ticks;
}
wait_queue_register(current);
}
unsigned int wakeup_thread_(struct thread_entry *thread)
{
switch (thread->state)
{
case STATE_BLOCKED:
case STATE_BLOCKED_W_TMO:
wait_queue_remove(thread);
thread->state = STATE_RUNNING;
SDL_SemPost(thread->context.s);
return THREAD_OK;
}
return THREAD_NONE;
}
void thread_thaw(unsigned int thread_id)
{
struct thread_entry *thread = __thread_id_entry(thread_id);
if (thread->id == thread_id && thread->state == STATE_FROZEN)
{
thread->state = STATE_RUNNING;
SDL_SemPost(thread->context.s);
}
}
int runthread(void *data)
{
/* Cannot access thread variables before locking the mutex as the
data structures may not be filled-in yet. */
SDL_LockMutex(m);
struct thread_entry *current = (struct thread_entry *)data;
__running_self_entry() = current;
jmp_buf *current_jmpbuf = &thread_jmpbufs[THREAD_ID_SLOT(current->id)];
/* Setup jump for exit */
if (setjmp(*current_jmpbuf) == 0)
{
/* Run the thread routine */
if (current->state == STATE_FROZEN)
{
SDL_UnlockMutex(m);
SDL_SemWait(current->context.s);
SDL_LockMutex(m);
__running_self_entry() = current;
}
if (threads_status == THREADS_RUN)
{
current->context.start();
THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
THREAD_ID_SLOT(current->id),
THREAD_SDL_GET_NAME(current));
/* Thread routine returned - suicide */
}
thread_exit();
}
else
{
/* Unlock and exit */
SDL_UnlockMutex(m);
}
return 0;
}
unsigned int create_thread(void (*function)(void),
void* stack, size_t stack_size,
unsigned flags, const char *name)
{
THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");
struct thread_entry *thread = thread_alloc();
if (thread == NULL)
{
DEBUGF("Failed to find thread slot\n");
return 0;
}
SDL_sem *s = SDL_CreateSemaphore(0);
if (s == NULL)
{
DEBUGF("Failed to create semaphore\n");
return 0;
}
SDL_Thread *t = SDL_CreateThread(runthread, thread);
if (t == NULL)
{
DEBUGF("Failed to create SDL thread\n");
SDL_DestroySemaphore(s);
return 0;
}
thread->name = name;
thread->state = (flags & CREATE_THREAD_FROZEN) ?
STATE_FROZEN : STATE_RUNNING;
thread->context.start = function;
thread->context.t = t;
thread->context.s = s;
THREAD_SDL_DEBUGF("New Thread: %lu (%s)\n",
(unsigned long)thread->id,
THREAD_SDL_GET_NAME(thread));
return thread->id;
(void)stack; (void)stack_size;
}
void thread_exit(void)
{
struct thread_entry *current = __running_self_entry();
int oldlevel = disable_irq_save();
SDL_Thread *t = current->context.t;
SDL_sem *s = current->context.s;
/* Wait the last thread here and keep this one or SDL will leak it since
* it doesn't free its own library allocations unless a wait is performed.
* Such behavior guards against the memory being invalid by the time
* SDL_WaitThread is reached and also against two different threads having
* the same pointer. It also makes SDL_WaitThread a non-concurrent function.
*
* However, see more below about SDL_KillThread.
*/
SDL_WaitThread(current->context.told, NULL);
current->context.t = NULL;
current->context.s = NULL;
current->context.told = t;
unsigned int id = current->id;
new_thread_id(current);
current->state = STATE_KILLED;
wait_queue_wake(&current->queue);
SDL_DestroySemaphore(s);
/* Do a graceful exit - perform the longjmp back into the thread
function to return */
restore_irq(oldlevel);
thread_free(current);
longjmp(thread_jmpbufs[THREAD_ID_SLOT(id)], 1);
/* This should never and must never be reached - if it is, the
* state is corrupted */
THREAD_PANICF("thread_exit->K:*R (ID: %d)", id);
while (1);
}
void thread_wait(unsigned int thread_id)
{
struct thread_entry *current = __running_self_entry();
struct thread_entry *thread = __thread_id_entry(thread_id);
if (thread->id == thread_id && thread->state != STATE_KILLED)
{
block_thread(current, TIMEOUT_BLOCK, &thread->queue);
switch_thread();
}
}
/* Initialize SDL threading */
void init_threads(void)
{
m = SDL_CreateMutex();
if (SDL_LockMutex(m) == -1)
{
fprintf(stderr, "Couldn't lock mutex\n");
return;
}
thread_alloc_init();
struct thread_entry *thread = thread_alloc();
if (thread == NULL)
{
fprintf(stderr, "Main thread alloc failed\n");
return;
}
/* Slot 0 is reserved for the main thread - initialize it here and
then create the SDL thread - it is possible to have a quick, early
shutdown try to access the structure. */
thread->name = __main_thread_name;
thread->state = STATE_RUNNING;
thread->context.s = SDL_CreateSemaphore(0);
thread->context.t = NULL; /* NULL for the implicit main thread */
__running_self_entry() = thread;
if (thread->context.s == NULL)
{
fprintf(stderr, "Failed to create main semaphore\n");
return;
}
/* Tell all threads jump back to their start routines, unlock and exit
gracefully - we'll check each one in turn for it's status. Threads
_could_ terminate via thread_exit or multiple threads could exit
on each unlock but that is safe. */
/* Setup jump for exit */
if (setjmp(thread_jmpbufs[THREAD_ID_SLOT(thread->id)]) == 0)
{
THREAD_SDL_DEBUGF("Main Thread: %lu (%s)\n",
(unsigned long)thread->id,
THREAD_SDL_GET_NAME(thread));
return;
}
SDL_UnlockMutex(m);
/* Set to 'COMMAND_DONE' when other rockbox threads have exited. */
while (threads_status < THREADS_EXIT_COMMAND_DONE)
SDL_Delay(10);
SDL_DestroyMutex(m);
/* We're the main thead - perform exit - doesn't return. */
sim_do_exit();
}
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