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  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <stdbool.h>
  23 #include <time.h>
  24 #include <SDL.h>
  25 #include <SDL_thread.h>
  26 #include <stdlib.h>
  27 #include <memory.h>
  28 #include <setjmp.h>
  29 #include "system-sdl.h"
  30 #include "thread-sdl.h"
  31 #include "system.h"
  32 #include "kernel.h"
  33 #include "thread.h"
  34 #include "debug.h"
  35
  36 /* Define this as 1 to show informational messages that are not errors. */
  37 #define THREAD_SDL_DEBUGF_ENABLED 0
  38
  39 #if THREAD_SDL_DEBUGF_ENABLED
  40 #define THREAD_SDL_DEBUGF(...) DEBUGF(__VA_ARGS__)
  41 static char __name[32];
  42 #define THREAD_SDL_GET_NAME(thread) \
  43     ({ thread_get_name(__name, ARRAYLEN(__name), thread); __name; })
  44 #else
  45 #define THREAD_SDL_DEBUGF(...)
  46 #define THREAD_SDL_GET_NAME(thread)
  47 #endif
  48
  49 #define THREAD_PANICF(str...) \
  50     ({ fprintf(stderr, str); exit(-1); })
  51
  52 /* Thread/core entries as in rockbox core */
  53 struct core_entry cores[NUM_CORES];
  54 struct thread_entry threads[MAXTHREADS];
  55 /* Jump buffers for graceful exit - kernel threads don't stay neatly
  56  * in their start routines responding to messages so this is the only
  57  * way to get them back in there so they may exit */
  58 static jmp_buf thread_jmpbufs[MAXTHREADS];
  59 static SDL_mutex *m;
  60 static bool threads_exit = false;
  61
  62 extern long start_tick;
  63
  64 void thread_sdl_shutdown(void)
  65 {
  66     int i;
  67     /* Take control */
  68     SDL_LockMutex(m);
  69
  70     /* Tell all threads jump back to their start routines, unlock and exit
  71        gracefully - we'll check each one in turn for it's status. Threads
  72        _could_ terminate via remove_thread or multiple threads could exit
  73        on each unlock but that is safe. */
  74     threads_exit = true;
  75
  76     for (i = 0; i < MAXTHREADS; i++)
  77     {
  78         struct thread_entry *thread = &threads[i];
  79         if (thread->context.t != NULL)
  80         {
  81             /* Signal thread on delay or block */
  82             SDL_Thread *t = thread->context.t;
  83             SDL_SemPost(thread->context.s);
  84             SDL_UnlockMutex(m);
  85             /* Wait for it to finish */
  86             SDL_WaitThread(t, NULL);
  87             /* Relock for next thread signal */
  88             SDL_LockMutex(m);
  89         }
  90     }
  91
  92     SDL_UnlockMutex(m);
  93     SDL_DestroyMutex(m);
  94 }
  95
  96 /* Do main thread creation in this file scope to avoid the need to double-
  97    return to a prior call-level which would be unaware of the fact setjmp
  98    was used */
  99 extern void app_main(void *param);
 100 static int thread_sdl_app_main(void *param)
 101 {
 102     SDL_LockMutex(m);
 103     cores[CURRENT_CORE].running = &threads[0];
 104
 105     /* Set the jump address for return */
 106     if (setjmp(thread_jmpbufs[0]) == 0)
 107     {
 108         app_main(param);
 109         /* should not ever be reached but... */
 110         THREAD_PANICF("app_main returned!\n");
 111     }
 112
 113     /* Unlock and exit */
 114     SDL_UnlockMutex(m);
 115     return 0;
 116 }
 117
 118 /* Initialize SDL threading */
 119 bool thread_sdl_init(void *param)
 120 {
 121     struct thread_entry *thread;
 122     memset(cores, 0, sizeof(cores));
 123     memset(threads, 0, sizeof(threads));
 124
 125     m = SDL_CreateMutex();
 126
 127     if (SDL_LockMutex(m) == -1)
 128     {
 129         fprintf(stderr, "Couldn't lock mutex\n");
 130         return false;
 131     }
 132
 133     /* Slot 0 is reserved for the main thread - initialize it here and
 134        then create the SDL thread - it is possible to have a quick, early
 135        shutdown try to access the structure. */
 136     thread = &threads[0];
 137     thread->stack = (uintptr_t *)"       ";
 138     thread->stack_size = 8;
 139     thread->name = "main";
 140     thread->state = STATE_RUNNING;
 141     thread->context.s = SDL_CreateSemaphore(0);
 142     cores[CURRENT_CORE].running = thread;
 143
 144     if (thread->context.s == NULL)
 145     {
 146         fprintf(stderr, "Failed to create main semaphore\n");
 147         return false;
 148     }
 149
 150     thread->context.t = SDL_CreateThread(thread_sdl_app_main, param);
 151
 152     if (thread->context.t == NULL)
 153     {
 154         SDL_DestroySemaphore(thread->context.s);
 155         fprintf(stderr, "Failed to create main thread\n");
 156         return false;
 157     }
 158
 159     THREAD_SDL_DEBUGF("Main thread: %p\n", thread);
 160
 161     SDL_UnlockMutex(m);
 162     return true;
 163 }
 164
 165 /* A way to yield and leave the threading system for extended periods */
 166 void thread_sdl_thread_lock(void *me)
 167 {
 168     SDL_LockMutex(m);
 169     cores[CURRENT_CORE].running = (struct thread_entry *)me;
 170
 171     if (threads_exit)
 172         thread_exit();
 173 }
 174
 175 void * thread_sdl_thread_unlock(void)
 176 {
 177     struct thread_entry *current = cores[CURRENT_CORE].running;
 178     SDL_UnlockMutex(m);
 179     return current;
 180 }
 181
 182 static struct thread_entry * find_empty_thread_slot(void)
 183 {
 184     struct thread_entry *thread = NULL;
 185     int n;
 186
 187     for (n = 0; n < MAXTHREADS; n++)
 188     {
 189         int state = threads[n].state;
 190
 191         if (state == STATE_KILLED)
 192         {
 193             thread = &threads[n];
 194             break;
 195         }
 196     }
 197
 198     return thread;
 199 }
 200
 201 static void add_to_list_l(struct thread_entry **list,
 202                           struct thread_entry *thread)
 203 {
 204     if (*list == NULL)
 205     {
 206         /* Insert into unoccupied list */
 207         thread->l.next = thread;
 208         thread->l.prev = thread;
 209         *list = thread;
 210     }
 211     else
 212     {
 213         /* Insert last */
 214         thread->l.next = *list;
 215         thread->l.prev = (*list)->l.prev;
 216         thread->l.prev->l.next = thread;
 217         (*list)->l.prev = thread;
 218     }
 219 }
 220
 221 static void remove_from_list_l(struct thread_entry **list,
 222                                struct thread_entry *thread)
 223 {
 224     if (thread == thread->l.next)
 225     {
 226         /* The only item */
 227         *list = NULL;
 228         return;
 229     }
 230
 231     if (thread == *list)
 232     {
 233         /* List becomes next item */
 234         *list = thread->l.next;
 235     }
 236
 237     /* Fix links to jump over the removed entry. */
 238     thread->l.prev->l.next = thread->l.next;
 239     thread->l.next->l.prev = thread->l.prev;
 240 }
 241
 242 struct thread_entry *thread_get_current(void)
 243 {
 244     return cores[CURRENT_CORE].running;
 245 }
 246
 247 void switch_thread(void)
 248 {
 249     struct thread_entry *current = cores[CURRENT_CORE].running;
 250
 251     enable_irq();
 252
 253     switch (current->state)
 254     {
 255     case STATE_RUNNING:
 256     {
 257         SDL_UnlockMutex(m);
 258         /* Any other thread waiting already will get it first */
 259         SDL_LockMutex(m);
 260         break;
 261         } /* STATE_RUNNING: */
 262
 263     case STATE_BLOCKED:
 264     {
 265         int oldlevel;
 266
 267         SDL_UnlockMutex(m);
 268         SDL_SemWait(current->context.s);
 269         SDL_LockMutex(m);
 270
 271         oldlevel = disable_irq_save();
 272         current->state = STATE_RUNNING;
 273         restore_irq(oldlevel);
 274         break;
 275         } /* STATE_BLOCKED: */
 276
 277     case STATE_BLOCKED_W_TMO:
 278     {
 279         int result, oldlevel;
 280
 281         SDL_UnlockMutex(m);
 282         result = SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 283         SDL_LockMutex(m);
 284
 285         oldlevel = disable_irq_save();
 286
 287         if (current->state == STATE_BLOCKED_W_TMO)
 288         {
 289             /* Timed out */
 290             remove_from_list_l(current->bqp, current);
 291
 292 #ifdef HAVE_WAKEUP_EXT_CB
 293             if (current->wakeup_ext_cb != NULL)
 294                 current->wakeup_ext_cb(current);
 295 #endif
 296             current->state = STATE_RUNNING;
 297         }
 298
 299         if (result == SDL_MUTEX_TIMEDOUT)
 300         {
 301             /* Other signals from an explicit wake could have been made before
 302              * arriving here if we timed out waiting for the semaphore. Make
 303              * sure the count is reset. */
 304             while (SDL_SemValue(current->context.s) > 0)
 305                 SDL_SemTryWait(current->context.s);
 306         }
 307
 308         restore_irq(oldlevel);
 309         break;
 310         } /* STATE_BLOCKED_W_TMO: */
 311
 312     case STATE_SLEEPING:
 313     {
 314         SDL_UnlockMutex(m);
 315         SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 316         SDL_LockMutex(m);
 317         current->state = STATE_RUNNING;
 318         break;
 319         } /* STATE_SLEEPING: */
 320     }
 321
 322     cores[CURRENT_CORE].running = current;
 323
 324     if (threads_exit)
 325         thread_exit();
 326 }
 327
 328 void sleep_thread(int ticks)
 329 {
 330     struct thread_entry *current = cores[CURRENT_CORE].running;
 331     int rem;
 332
 333     current->state = STATE_SLEEPING;
 334
 335     rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
 336     if (rem < 0)
 337         rem = 0;
 338
 339     current->tmo_tick = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
 340 }
 341
 342 void block_thread(struct thread_entry *current)
 343 {
 344     current->state = STATE_BLOCKED;
 345     add_to_list_l(current->bqp, current);
 346 }
 347
 348 void block_thread_w_tmo(struct thread_entry *current, int ticks)
 349 {
 350     current->state = STATE_BLOCKED_W_TMO;
 351     current->tmo_tick = (1000/HZ)*ticks;
 352     add_to_list_l(current->bqp, current);
 353 }
 354
 355 unsigned int wakeup_thread(struct thread_entry **list)
 356 {
 357     struct thread_entry *thread = *list;
 358
 359     if (thread != NULL)
 360     {
 361         switch (thread->state)
 362         {
 363         case STATE_BLOCKED:
 364         case STATE_BLOCKED_W_TMO:
 365             remove_from_list_l(list, thread);
 366             thread->state = STATE_RUNNING;
 367             SDL_SemPost(thread->context.s);
 368             return THREAD_OK;
 369         }
 370     }
 371
 372     return THREAD_NONE;
 373 }
 374
 375 unsigned int thread_queue_wake(struct thread_entry **list)
 376 {
 377     unsigned int result = THREAD_NONE;
 378
 379     for (;;)
 380     {
 381         unsigned int rc = wakeup_thread(list);
 382
 383         if (rc == THREAD_NONE)
 384             break;
 385
 386         result |= rc;
 387     }
 388
 389     return result;
 390 }
 391
 392 void thread_thaw(struct thread_entry *thread)
 393 {
 394     if (thread->state == STATE_FROZEN)
 395     {
 396         thread->state = STATE_RUNNING;
 397         SDL_SemPost(thread->context.s);
 398     }
 399 }
 400
 401 int runthread(void *data)
 402 {
 403     struct thread_entry *current;
 404     jmp_buf *current_jmpbuf;
 405
 406     /* Cannot access thread variables before locking the mutex as the
 407        data structures may not be filled-in yet. */
 408     SDL_LockMutex(m);
 409     cores[CURRENT_CORE].running = (struct thread_entry *)data;
 410     current = cores[CURRENT_CORE].running;
 411     current_jmpbuf = &thread_jmpbufs[current - threads];
 412
 413     /* Setup jump for exit */
 414     if (setjmp(*current_jmpbuf) == 0)
 415     {
 416         /* Run the thread routine */
 417         if (current->state == STATE_FROZEN)
 418         {
 419             SDL_UnlockMutex(m);
 420             SDL_SemWait(current->context.s);
 421             SDL_LockMutex(m);
 422             cores[CURRENT_CORE].running = current;
 423         }
 424
 425         if (!threads_exit)
 426         {
 427             current->context.start();
 428             THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
 429                               current - threads, THREAD_SDL_GET_NAME(current));
 430             /* Thread routine returned - suicide */
 431         }
 432
 433         thread_exit();
 434     }
 435     else
 436     {
 437         /* Unlock and exit */
 438         SDL_UnlockMutex(m);
 439     }
 440
 441     return 0;
 442 }
 443
 444 struct thread_entry*
 445     create_thread(void (*function)(void), void* stack, size_t stack_size,
 446                   unsigned flags, const char *name)
 447 {
 448     struct thread_entry *thread;
 449     SDL_Thread* t;
 450     SDL_sem *s;
 451
 452     THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");
 453
 454     thread = find_empty_thread_slot();
 455     if (thread == NULL)
 456     {
 457         DEBUGF("Failed to find thread slot\n");
 458         return NULL;
 459     }
 460
 461     s = SDL_CreateSemaphore(0);
 462     if (s == NULL)
 463     {
 464         DEBUGF("Failed to create semaphore\n");
 465         return NULL;
 466     }
 467
 468     t = SDL_CreateThread(runthread, thread);
 469     if (t == NULL)
 470     {
 471         DEBUGF("Failed to create SDL thread\n");
 472         SDL_DestroySemaphore(s);
 473         return NULL;
 474     }
 475
 476     thread->stack = stack;
 477     thread->stack_size = stack_size;
 478     thread->name = name;
 479     thread->state = (flags & CREATE_THREAD_FROZEN) ?
 480         STATE_FROZEN : STATE_RUNNING;
 481     thread->context.start = function;
 482     thread->context.t = t;
 483     thread->context.s = s;
 484
 485     THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
 486                       thread - threads, THREAD_SDL_GET_NAME(thread));
 487
 488     return thread;
 489 }
 490
 491 void init_threads(void)
 492 {
 493     /* Main thread is already initialized */
 494     if (cores[CURRENT_CORE].running != &threads[0])
 495     {
 496         THREAD_PANICF("Wrong main thread in init_threads: %p\n",
 497                       cores[CURRENT_CORE].running);
 498     }
 499
 500     THREAD_SDL_DEBUGF("First Thread: %d (%s)\n",
 501             0, THREAD_SDL_GET_NAME(&threads[0]));
 502 }
 503
 504 void remove_thread(struct thread_entry *thread)
 505 {
 506     struct thread_entry *current = cores[CURRENT_CORE].running;
 507     SDL_Thread *t;
 508     SDL_sem *s;
 509
 510     int oldlevel = disable_irq_save();
 511
 512     if (thread == NULL)
 513     {
 514         thread = current;
 515     }
 516
 517     t = thread->context.t;
 518     s = thread->context.s;
 519     thread->context.t = NULL;
 520
 521     if (thread != current)
 522     {
 523         switch (thread->state)
 524         {
 525         case STATE_BLOCKED:
 526         case STATE_BLOCKED_W_TMO:
 527             /* Remove thread from object it's waiting on */
 528             remove_from_list_l(thread->bqp, thread);
 529
 530 #ifdef HAVE_WAKEUP_EXT_CB
 531             if (thread->wakeup_ext_cb != NULL)
 532                 thread->wakeup_ext_cb(thread);
 533 #endif
 534             break;
 535         }
 536
 537         SDL_SemPost(s);
 538     }
 539
 540     THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
 541         thread - threads, THREAD_SDL_GET_NAME(thread));
 542
 543     thread->state = STATE_KILLED;
 544     thread_queue_wake(&thread->queue);
 545
 546     SDL_DestroySemaphore(s);
 547
 548     if (thread == current)
 549     {
 550         /* Do a graceful exit - perform the longjmp back into the thread
 551            function to return */
 552         restore_irq(oldlevel);
 553         longjmp(thread_jmpbufs[current - threads], 1);
 554     }
 555
 556     SDL_KillThread(t);
 557     restore_irq(oldlevel);
 558 }
 559
 560 void thread_exit(void)
 561 {
 562     remove_thread(NULL);
 563 }
 564
 565 void thread_wait(struct thread_entry *thread)
 566 {
 567     struct thread_entry *current = cores[CURRENT_CORE].running;
 568
 569     if (thread == NULL)
 570         thread = current;
 571
 572     if (thread->state != STATE_KILLED)
 573     {
 574         current->bqp = &thread->queue;
 575         block_thread(current);
 576         switch_thread();
 577     }
 578 }
 579
 580 int thread_stack_usage(const struct thread_entry *thread)
 581 {
 582     return 50;
 583     (void)thread;
 584 }
 585
 586 unsigned thread_get_status(const struct thread_entry *thread)
 587 {
 588     return thread->state;
 589 }
 590
 591 /* Return name if one or ID if none */
 592 void thread_get_name(char *buffer, int size,
 593                      struct thread_entry *thread)
 594 {
 595     if (size <= 0)
 596         return;
 597
 598     *buffer = '\0';
 599
 600     if (thread)
 601     {
 602         /* Display thread name if one or ID if none */
 603         bool named = thread->name && *thread->name;
 604         const char *fmt = named ? "%s" : "%08lX";
 605         intptr_t name = named ?
 606             (intptr_t)thread->name : (intptr_t)thread;
 607         snprintf(buffer, size, fmt, name);
 608     }
 609 }