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