uisimulator/sdl/thread-sdl.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 Dan Everton
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include <stdbool.h>
  21 #include <time.h>
  22 #include <SDL.h>
  23 #include <SDL_thread.h>
  24 #include <stdlib.h>
  25 #include <memory.h>
  26 #include <setjmp.h>
  27 #include "system-sdl.h"
  28 #include "thread-sdl.h"
  29 #include "kernel.h"
  30 #include "thread.h"
  31 #include "debug.h"
  32
  33 /* Define this as 1 to show informational messages that are not errors. */
  34 #define THREAD_SDL_DEBUGF_ENABLED 0
  35
  36 #if THREAD_SDL_DEBUGF_ENABLED
  37 #define THREAD_SDL_DEBUGF(...) DEBUGF(__VA_ARGS__)
  38 static char __name[32];
  39 #define THREAD_SDL_GET_NAME(thread) \
  40     ({ thread_get_name(__name, sizeof(__name)/sizeof(__name[0]), thread); __name; })
  41 #else
  42 #define THREAD_SDL_DEBUGF(...)
  43 #define THREAD_SDL_GET_NAME(thread)
  44 #endif
  45
  46 #define THREAD_PANICF(str...) \
  47     ({ fprintf(stderr, str); exit(-1); })
  48
  49 /* Thread/core entries as in rockbox core */
  50 struct core_entry cores[NUM_CORES];
  51 struct thread_entry threads[MAXTHREADS];
  52 /* Jump buffers for graceful exit - kernel threads don't stay neatly
  53  * in their start routines responding to messages so this is the only
  54  * way to get them back in there so they may exit */
  55 static jmp_buf thread_jmpbufs[MAXTHREADS];
  56 static SDL_mutex *m;
  57 static struct thread_entry *running;
  58 static bool threads_exit = false;
  59
  60 extern long start_tick;
  61
  62 void thread_sdl_shutdown(void)
  63 {
  64     int i;
  65     /* Take control */
  66     SDL_LockMutex(m);
  67
  68     /* Tell all threads jump back to their start routines, unlock and exit
  69        gracefully - we'll check each one in turn for it's status. Threads
  70        _could_ terminate via remove_thread or multiple threads could exit
  71        on each unlock but that is safe. */
  72     threads_exit = true;
  73
  74     for (i = 0; i < MAXTHREADS; i++)
  75     {
  76         struct thread_entry *thread = &threads[i];
  77         if (thread->context.t != NULL)
  78         {
  79             /* Signal thread on delay or block */
  80             SDL_Thread *t = thread->context.t;
  81             SDL_CondSignal(thread->context.c);
  82             SDL_UnlockMutex(m);
  83             /* Wait for it to finish */
  84             SDL_WaitThread(t, NULL);
  85             /* Relock for next thread signal */
  86             SDL_LockMutex(m);
  87         }
  88     }
  89
  90     SDL_UnlockMutex(m);
  91     SDL_DestroyMutex(m);
  92 }
  93
  94 /* Do main thread creation in this file scope to avoid the need to double-
  95    return to a prior call-level which would be unaware of the fact setjmp
  96    was used */
  97 extern void app_main(void *param);
  98 static int thread_sdl_app_main(void *param)
  99 {
 100     SDL_LockMutex(m);
 101     running = &threads[0];
 102
 103     /* Set the jump address for return */
 104     if (setjmp(thread_jmpbufs[0]) == 0)
 105     {
 106         app_main(param);
 107         /* should not ever be reached but... */
 108         THREAD_PANICF("app_main returned!\n");
 109     }
 110
 111     /* Unlock and exit */
 112     SDL_UnlockMutex(m);
 113     return 0;
 114 }
 115
 116 /* Initialize SDL threading */
 117 bool thread_sdl_init(void *param)
 118 {
 119     memset(threads, 0, sizeof(threads));
 120
 121     m = SDL_CreateMutex();
 122
 123     if (SDL_LockMutex(m) == -1)
 124     {
 125         fprintf(stderr, "Couldn't lock mutex\n");
 126         return false;
 127     }
 128
 129     /* Slot 0 is reserved for the main thread - initialize it here and
 130        then create the SDL thread - it is possible to have a quick, early
 131        shutdown try to access the structure. */
 132     running = &threads[0];
 133     running->stack = "       ";
 134     running->stack_size = 8;
 135     running->name = "main";
 136     running->state = STATE_RUNNING;
 137     running->context.c = SDL_CreateCond();
 138
 139     if (running->context.c == NULL)
 140     {
 141         fprintf(stderr, "Failed to create main condition variable\n");
 142         return false;
 143     }
 144
 145     running->context.t = SDL_CreateThread(thread_sdl_app_main, param);
 146
 147     if (running->context.t == NULL)
 148     {
 149         fprintf(stderr, "Failed to create main thread\n");
 150         return false;
 151     }
 152
 153     THREAD_SDL_DEBUGF("Main thread: %p\n", running);
 154
 155     SDL_UnlockMutex(m);
 156     return true;
 157 }
 158
 159 /* A way to yield and leave the threading system for extended periods */
 160 void thread_sdl_thread_lock(void *me)
 161 {
 162     SDL_LockMutex(m);
 163     running = (struct thread_entry *)me;
 164
 165     if (threads_exit)
 166         remove_thread(NULL);
 167 }
 168
 169 void * thread_sdl_thread_unlock(void)
 170 {
 171     struct thread_entry *current = running;
 172     SDL_UnlockMutex(m);
 173     return current;
 174 }
 175
 176 static int find_empty_thread_slot(void)
 177 {
 178     int n;
 179
 180     for (n = 0; n < MAXTHREADS; n++)
 181     {
 182         int state = threads[n].state;
 183
 184         if (state == STATE_KILLED)
 185             break;
 186     }
 187
 188     return n;
 189 }
 190
 191 static void add_to_list_l(struct thread_entry **list,
 192                           struct thread_entry *thread)
 193 {
 194     if (*list == NULL)
 195     {
 196         /* Insert into unoccupied list */
 197         thread->l.next = thread;
 198         thread->l.prev = thread;
 199         *list = thread;
 200     }
 201     else
 202     {
 203         /* Insert last */
 204         thread->l.next = *list;
 205         thread->l.prev = (*list)->l.prev;
 206         thread->l.prev->l.next = thread;
 207         (*list)->l.prev = thread;
 208     }
 209 }
 210
 211 static void remove_from_list_l(struct thread_entry **list,
 212                                struct thread_entry *thread)
 213 {
 214     if (thread == thread->l.next)
 215     {
 216         /* The only item */
 217         *list = NULL;
 218         return;
 219     }
 220
 221     if (thread == *list)
 222     {
 223         /* List becomes next item */
 224         *list = thread->l.next;
 225     }
 226
 227     /* Fix links to jump over the removed entry. */
 228     thread->l.prev->l.next = thread->l.next;
 229     thread->l.next->l.prev = thread->l.prev;
 230 }
 231
 232 static inline void run_blocking_ops(void)
 233 {
 234     set_irq_level(0);
 235 }
 236
 237 struct thread_entry *thread_get_current(void)
 238 {
 239     return running;
 240 }
 241
 242 void switch_thread(struct thread_entry *old)
 243 {
 244     struct thread_entry *current = running;
 245
 246     SDL_UnlockMutex(m);
 247     /* Any other thread waiting already will get it first */
 248     SDL_LockMutex(m);
 249     running = current;
 250
 251     if (threads_exit)
 252         remove_thread(NULL);
 253
 254     (void)old;
 255 }
 256
 257 void sleep_thread(int ticks)
 258 {
 259     struct thread_entry *current;
 260     int rem;
 261
 262     current = running;
 263     current->state = STATE_SLEEPING;
 264
 265     rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
 266     if (rem < 0)
 267         rem = 0;
 268
 269     rem = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
 270
 271     if (rem == 0)
 272     {
 273         /* Unlock and give up rest of quantum */
 274         SDL_UnlockMutex(m);
 275         SDL_Delay(0);
 276         SDL_LockMutex(m);
 277     }
 278     else
 279     {
 280         /* These sleeps must be signalable for thread exit */
 281         SDL_CondWaitTimeout(current->context.c, m, rem);
 282     }
 283
 284     running = current;
 285
 286     current->state = STATE_RUNNING;
 287
 288     if (threads_exit)
 289         remove_thread(NULL);
 290 }
 291
 292 int runthread(void *data)
 293 {
 294     struct thread_entry *current;
 295     jmp_buf *current_jmpbuf;
 296
 297     /* Cannot access thread variables before locking the mutex as the
 298        data structures may not be filled-in yet. */
 299     SDL_LockMutex(m);
 300     running = (struct thread_entry *)data;
 301     current = running;
 302     current_jmpbuf = &thread_jmpbufs[running - threads];
 303
 304     /* Setup jump for exit */
 305     if (setjmp(*current_jmpbuf) == 0)
 306     {
 307         /* Run the thread routine */
 308         if (current->state == STATE_FROZEN)
 309         {
 310             SDL_CondWait(current->context.c, m);
 311             running = current;
 312
 313         }
 314
 315         if (!threads_exit)
 316         {
 317             current->context.start();
 318             THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
 319                               current - threads, THREAD_SDL_GET_NAME(current));
 320             /* Thread routine returned - suicide */
 321         }
 322
 323         remove_thread(NULL);
 324     }
 325     else
 326     {
 327         /* Unlock and exit */
 328         SDL_UnlockMutex(m);
 329     }
 330
 331     return 0;
 332 }
 333
 334 struct thread_entry*
 335     create_thread(void (*function)(void), void* stack, int stack_size,
 336                   unsigned flags, const char *name)
 337 {
 338     /** Avoid compiler warnings */
 339     SDL_Thread* t;
 340     SDL_cond *cond;
 341     int slot;
 342
 343     THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");
 344
 345     slot = find_empty_thread_slot();
 346     if (slot >= MAXTHREADS)
 347     {
 348         DEBUGF("Failed to find thread slot\n");
 349         return NULL;
 350     }
 351
 352     cond = SDL_CreateCond();
 353     if (cond == NULL)
 354     {
 355         DEBUGF("Failed to create condition variable\n");
 356         return NULL;
 357     }
 358
 359     t = SDL_CreateThread(runthread, &threads[slot]);
 360     if (t == NULL)
 361     {
 362         DEBUGF("Failed to create SDL thread\n");
 363         SDL_DestroyCond(cond);
 364         return NULL;
 365     }
 366
 367     threads[slot].stack = stack;
 368     threads[slot].stack_size = stack_size;
 369     threads[slot].name = name;
 370     threads[slot].state = (flags & CREATE_THREAD_FROZEN) ?
 371         STATE_FROZEN : STATE_RUNNING;
 372     threads[slot].context.start = function;
 373     threads[slot].context.t = t;
 374     threads[slot].context.c = cond;
 375
 376     THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
 377                       slot, THREAD_SDL_GET_NAME(&threads[slot]));
 378
 379     return &threads[slot];
 380 }
 381
 382 void _block_thread(struct thread_queue *tq)
 383 {
 384     struct thread_entry *thread = running;
 385
 386     thread->state = STATE_BLOCKED;
 387     thread->bqp = tq;
 388     add_to_list_l(&tq->queue, thread);
 389
 390     run_blocking_ops();
 391
 392     SDL_CondWait(thread->context.c, m);
 393     running = thread;
 394
 395     if (threads_exit)
 396         remove_thread(NULL);
 397 }
 398
 399 void block_thread_w_tmo(struct thread_queue *tq, int ticks)
 400 {
 401     struct thread_entry *thread = running;
 402
 403     thread->state = STATE_BLOCKED_W_TMO;
 404     thread->bqp = tq;
 405     add_to_list_l(&tq->queue, thread);
 406
 407     run_blocking_ops();
 408
 409     SDL_CondWaitTimeout(thread->context.c, m, (1000/HZ) * ticks);
 410     running = thread;
 411
 412     if (thread->state == STATE_BLOCKED_W_TMO)
 413     {
 414         /* Timed out */
 415         remove_from_list_l(&tq->queue, thread);
 416         thread->state = STATE_RUNNING;
 417     }
 418
 419     if (threads_exit)
 420         remove_thread(NULL);
 421 }
 422
 423 struct thread_entry * _wakeup_thread(struct thread_queue *tq)
 424 {
 425     struct thread_entry *thread = tq->queue;
 426
 427     if (thread == NULL)
 428     {
 429         return NULL;
 430     }
 431
 432     switch (thread->state)
 433     {
 434     case STATE_BLOCKED:
 435     case STATE_BLOCKED_W_TMO:
 436         remove_from_list_l(&tq->queue, thread);
 437         thread->state = STATE_RUNNING;
 438         SDL_CondSignal(thread->context.c);
 439         return thread;
 440     default:
 441         return NULL;
 442     }
 443 }
 444
 445 void thread_thaw(struct thread_entry *thread)
 446 {
 447     if (thread->state == STATE_FROZEN)
 448     {
 449         thread->state = STATE_RUNNING;
 450         SDL_CondSignal(thread->context.c);
 451     }
 452 }
 453
 454 void init_threads(void)
 455 {
 456     /* Main thread is already initialized */
 457     if (running != &threads[0])
 458     {
 459         THREAD_PANICF("Wrong main thread in init_threads: %p\n", running);
 460     }
 461
 462     THREAD_SDL_DEBUGF("First Thread: %d (%s)\n",
 463             0, THREAD_SDL_GET_NAME(&threads[0]));
 464 }
 465
 466 void remove_thread(struct thread_entry *thread)
 467 {
 468     struct thread_entry *current = running;
 469     SDL_Thread *t;
 470     SDL_cond *c;
 471
 472     int oldlevel = set_irq_level(HIGHEST_IRQ_LEVEL);
 473
 474     if (thread == NULL)
 475     {
 476         thread = current;
 477     }
 478
 479     t = thread->context.t;
 480     c = thread->context.c;
 481     thread->context.t = NULL;
 482
 483     if (thread != current)
 484     {
 485         switch (thread->state)
 486         {
 487         case STATE_BLOCKED:
 488         case STATE_BLOCKED_W_TMO:
 489             /* Remove thread from object it's waiting on */
 490             remove_from_list_l(&thread->bqp->queue, thread);
 491             break;
 492         }
 493
 494         SDL_CondSignal(c);
 495     }
 496
 497     THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
 498         thread - threads, THREAD_SDL_GET_NAME(thread));
 499
 500     thread_queue_wake_no_listlock(&thread->queue);
 501     thread->state = STATE_KILLED;
 502
 503     SDL_DestroyCond(c);
 504
 505     if (thread == current)
 506     {
 507         /* Do a graceful exit - perform the longjmp back into the thread
 508            function to return */
 509         set_irq_level(oldlevel);
 510         longjmp(thread_jmpbufs[current - threads], 1);
 511     }
 512
 513     SDL_KillThread(t);
 514     set_irq_level(oldlevel);
 515 }
 516
 517 void thread_wait(struct thread_entry *thread)
 518 {
 519     if (thread == NULL)
 520         thread = running;
 521
 522     if (thread->state != STATE_KILLED)
 523     {
 524         block_thread_no_listlock(&thread->queue);
 525     }
 526 }
 527
 528 int thread_stack_usage(const struct thread_entry *thread)
 529 {
 530     return 50;
 531     (void)thread;
 532 }
 533
 534 unsigned thread_get_status(const struct thread_entry *thread)
 535 {
 536     return thread->state;
 537 }
 538
 539 /* Return name if one or ID if none */
 540 void thread_get_name(char *buffer, int size,
 541                      struct thread_entry *thread)
 542 {
 543     if (size <= 0)
 544         return;
 545
 546     *buffer = '\0';
 547
 548     if (thread)
 549     {
 550         /* Display thread name if one or ID if none */
 551         bool named = thread->name && *thread->name;
 552         const char *fmt = named ? "%s" : "%08lX";
 553         intptr_t name = named ?
 554             (intptr_t)thread->name : (intptr_t)thread;
 555         snprintf(buffer, size, fmt, name);
 556     }
 557 }