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 static void new_thread_id(unsigned int slot_num,
  97                           struct thread_entry *thread)
  98 {
  99     unsigned int version =
 100         (thread->id + (1u << THREAD_ID_VERSION_SHIFT))
 101             & THREAD_ID_VERSION_MASK;
 102
 103     if (version == 0)
 104         version = 1u << THREAD_ID_VERSION_SHIFT;
 105
 106     thread->id = version | (slot_num & THREAD_ID_SLOT_MASK);
 107 }
 108
 109 static struct thread_entry * find_empty_thread_slot(void)
 110 {
 111     struct thread_entry *thread = NULL;
 112     int n;
 113
 114     for (n = 0; n < MAXTHREADS; n++)
 115     {
 116         int state = threads[n].state;
 117
 118         if (state == STATE_KILLED)
 119         {
 120             thread = &threads[n];
 121             break;
 122         }
 123     }
 124
 125     return thread;
 126 }
 127
 128 /* Do main thread creation in this file scope to avoid the need to double-
 129    return to a prior call-level which would be unaware of the fact setjmp
 130    was used */
 131 extern void app_main(void *param);
 132 static int thread_sdl_app_main(void *param)
 133 {
 134     SDL_LockMutex(m);
 135     cores[CURRENT_CORE].running = &threads[0];
 136
 137     /* Set the jump address for return */
 138     if (setjmp(thread_jmpbufs[0]) == 0)
 139     {
 140         app_main(param);
 141         /* should not ever be reached but... */
 142         THREAD_PANICF("app_main returned!\n");
 143     }
 144
 145     /* Unlock and exit */
 146     SDL_UnlockMutex(m);
 147     return 0;
 148 }
 149
 150 /* Initialize SDL threading */
 151 bool thread_sdl_init(void *param)
 152 {
 153     struct thread_entry *thread;
 154     int n;
 155
 156     memset(cores, 0, sizeof(cores));
 157     memset(threads, 0, sizeof(threads));
 158
 159     m = SDL_CreateMutex();
 160
 161     if (SDL_LockMutex(m) == -1)
 162     {
 163         fprintf(stderr, "Couldn't lock mutex\n");
 164         return false;
 165     }
 166
 167     /* Initialize all IDs */
 168     for (n = 0; n < MAXTHREADS; n++)
 169         threads[n].id = THREAD_ID_INIT(n);
 170
 171     /* Slot 0 is reserved for the main thread - initialize it here and
 172        then create the SDL thread - it is possible to have a quick, early
 173        shutdown try to access the structure. */
 174     thread = &threads[0];
 175     thread->stack = (uintptr_t *)"       ";
 176     thread->stack_size = 8;
 177     thread->name = "main";
 178     thread->state = STATE_RUNNING;
 179     thread->context.s = SDL_CreateSemaphore(0);
 180     cores[CURRENT_CORE].running = thread;
 181
 182     if (thread->context.s == NULL)
 183     {
 184         fprintf(stderr, "Failed to create main semaphore\n");
 185         return false;
 186     }
 187
 188     thread->context.t = SDL_CreateThread(thread_sdl_app_main, param);
 189
 190     if (thread->context.t == NULL)
 191     {
 192         SDL_DestroySemaphore(thread->context.s);
 193         fprintf(stderr, "Failed to create main thread\n");
 194         return false;
 195     }
 196
 197     THREAD_SDL_DEBUGF("Main thread: %p\n", thread);
 198
 199     SDL_UnlockMutex(m);
 200     return true;
 201 }
 202
 203 /* A way to yield and leave the threading system for extended periods */
 204 void thread_sdl_thread_lock(void *me)
 205 {
 206     SDL_LockMutex(m);
 207     cores[CURRENT_CORE].running = (struct thread_entry *)me;
 208
 209     if (threads_exit)
 210         thread_exit();
 211 }
 212
 213 void * thread_sdl_thread_unlock(void)
 214 {
 215     struct thread_entry *current = cores[CURRENT_CORE].running;
 216     SDL_UnlockMutex(m);
 217     return current;
 218 }
 219
 220 struct thread_entry * thread_id_entry(unsigned int thread_id)
 221 {
 222     return (thread_id == THREAD_ID_CURRENT) ?
 223         cores[CURRENT_CORE].running :
 224         &threads[thread_id & THREAD_ID_SLOT_MASK];
 225 }
 226
 227 static void add_to_list_l(struct thread_entry **list,
 228                           struct thread_entry *thread)
 229 {
 230     if (*list == NULL)
 231     {
 232         /* Insert into unoccupied list */
 233         thread->l.next = thread;
 234         thread->l.prev = thread;
 235         *list = thread;
 236     }
 237     else
 238     {
 239         /* Insert last */
 240         thread->l.next = *list;
 241         thread->l.prev = (*list)->l.prev;
 242         thread->l.prev->l.next = thread;
 243         (*list)->l.prev = thread;
 244     }
 245 }
 246
 247 static void remove_from_list_l(struct thread_entry **list,
 248                                struct thread_entry *thread)
 249 {
 250     if (thread == thread->l.next)
 251     {
 252         /* The only item */
 253         *list = NULL;
 254         return;
 255     }
 256
 257     if (thread == *list)
 258     {
 259         /* List becomes next item */
 260         *list = thread->l.next;
 261     }
 262
 263     /* Fix links to jump over the removed entry. */
 264     thread->l.prev->l.next = thread->l.next;
 265     thread->l.next->l.prev = thread->l.prev;
 266 }
 267
 268 unsigned int thread_get_current(void)
 269 {
 270     return cores[CURRENT_CORE].running->id;
 271 }
 272
 273 void switch_thread(void)
 274 {
 275     struct thread_entry *current = cores[CURRENT_CORE].running;
 276
 277     enable_irq();
 278
 279     switch (current->state)
 280     {
 281     case STATE_RUNNING:
 282     {
 283         SDL_UnlockMutex(m);
 284         /* Any other thread waiting already will get it first */
 285         SDL_LockMutex(m);
 286         break;
 287         } /* STATE_RUNNING: */
 288
 289     case STATE_BLOCKED:
 290     {
 291         int oldlevel;
 292
 293         SDL_UnlockMutex(m);
 294         SDL_SemWait(current->context.s);
 295         SDL_LockMutex(m);
 296
 297         oldlevel = disable_irq_save();
 298         current->state = STATE_RUNNING;
 299         restore_irq(oldlevel);
 300         break;
 301         } /* STATE_BLOCKED: */
 302
 303     case STATE_BLOCKED_W_TMO:
 304     {
 305         int result, oldlevel;
 306
 307         SDL_UnlockMutex(m);
 308         result = SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 309         SDL_LockMutex(m);
 310
 311         oldlevel = disable_irq_save();
 312
 313         if (current->state == STATE_BLOCKED_W_TMO)
 314         {
 315             /* Timed out */
 316             remove_from_list_l(current->bqp, current);
 317
 318 #ifdef HAVE_WAKEUP_EXT_CB
 319             if (current->wakeup_ext_cb != NULL)
 320                 current->wakeup_ext_cb(current);
 321 #endif
 322             current->state = STATE_RUNNING;
 323         }
 324
 325         if (result == SDL_MUTEX_TIMEDOUT)
 326         {
 327             /* Other signals from an explicit wake could have been made before
 328              * arriving here if we timed out waiting for the semaphore. Make
 329              * sure the count is reset. */
 330             while (SDL_SemValue(current->context.s) > 0)
 331                 SDL_SemTryWait(current->context.s);
 332         }
 333
 334         restore_irq(oldlevel);
 335         break;
 336         } /* STATE_BLOCKED_W_TMO: */
 337
 338     case STATE_SLEEPING:
 339     {
 340         SDL_UnlockMutex(m);
 341         SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 342         SDL_LockMutex(m);
 343         current->state = STATE_RUNNING;
 344         break;
 345         } /* STATE_SLEEPING: */
 346     }
 347
 348     cores[CURRENT_CORE].running = current;
 349
 350     if (threads_exit)
 351         thread_exit();
 352 }
 353
 354 void sleep_thread(int ticks)
 355 {
 356     struct thread_entry *current = cores[CURRENT_CORE].running;
 357     int rem;
 358
 359     current->state = STATE_SLEEPING;
 360
 361     rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
 362     if (rem < 0)
 363         rem = 0;
 364
 365     current->tmo_tick = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
 366 }
 367
 368 void block_thread(struct thread_entry *current)
 369 {
 370     current->state = STATE_BLOCKED;
 371     add_to_list_l(current->bqp, current);
 372 }
 373
 374 void block_thread_w_tmo(struct thread_entry *current, int ticks)
 375 {
 376     current->state = STATE_BLOCKED_W_TMO;
 377     current->tmo_tick = (1000/HZ)*ticks;
 378     add_to_list_l(current->bqp, current);
 379 }
 380
 381 unsigned int wakeup_thread(struct thread_entry **list)
 382 {
 383     struct thread_entry *thread = *list;
 384
 385     if (thread != NULL)
 386     {
 387         switch (thread->state)
 388         {
 389         case STATE_BLOCKED:
 390         case STATE_BLOCKED_W_TMO:
 391             remove_from_list_l(list, thread);
 392             thread->state = STATE_RUNNING;
 393             SDL_SemPost(thread->context.s);
 394             return THREAD_OK;
 395         }
 396     }
 397
 398     return THREAD_NONE;
 399 }
 400
 401 unsigned int thread_queue_wake(struct thread_entry **list)
 402 {
 403     unsigned int result = THREAD_NONE;
 404
 405     for (;;)
 406     {
 407         unsigned int rc = wakeup_thread(list);
 408
 409         if (rc == THREAD_NONE)
 410             break;
 411
 412         result |= rc;
 413     }
 414
 415     return result;
 416 }
 417
 418 void thread_thaw(unsigned int thread_id)
 419 {
 420     struct thread_entry *thread = thread_id_entry(thread_id);
 421
 422     if (thread->id == thread_id && thread->state == STATE_FROZEN)
 423     {
 424         thread->state = STATE_RUNNING;
 425         SDL_SemPost(thread->context.s);
 426     }
 427 }
 428
 429 int runthread(void *data)
 430 {
 431     struct thread_entry *current;
 432     jmp_buf *current_jmpbuf;
 433
 434     /* Cannot access thread variables before locking the mutex as the
 435        data structures may not be filled-in yet. */
 436     SDL_LockMutex(m);
 437     cores[CURRENT_CORE].running = (struct thread_entry *)data;
 438     current = cores[CURRENT_CORE].running;
 439     current_jmpbuf = &thread_jmpbufs[current - threads];
 440
 441     /* Setup jump for exit */
 442     if (setjmp(*current_jmpbuf) == 0)
 443     {
 444         /* Run the thread routine */
 445         if (current->state == STATE_FROZEN)
 446         {
 447             SDL_UnlockMutex(m);
 448             SDL_SemWait(current->context.s);
 449             SDL_LockMutex(m);
 450             cores[CURRENT_CORE].running = current;
 451         }
 452
 453         if (!threads_exit)
 454         {
 455             current->context.start();
 456             THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
 457                               current - threads, THREAD_SDL_GET_NAME(current));
 458             /* Thread routine returned - suicide */
 459         }
 460
 461         thread_exit();
 462     }
 463     else
 464     {
 465         /* Unlock and exit */
 466         SDL_UnlockMutex(m);
 467     }
 468
 469     return 0;
 470 }
 471
 472 unsigned int create_thread(void (*function)(void),
 473                            void* stack, size_t stack_size,
 474                            unsigned flags, const char *name)
 475 {
 476     struct thread_entry *thread;
 477     SDL_Thread* t;
 478     SDL_sem *s;
 479
 480     THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");
 481
 482     thread = find_empty_thread_slot();
 483     if (thread == NULL)
 484     {
 485         DEBUGF("Failed to find thread slot\n");
 486         return 0;
 487     }
 488
 489     s = SDL_CreateSemaphore(0);
 490     if (s == NULL)
 491     {
 492         DEBUGF("Failed to create semaphore\n");
 493         return 0;
 494     }
 495
 496     t = SDL_CreateThread(runthread, thread);
 497     if (t == NULL)
 498     {
 499         DEBUGF("Failed to create SDL thread\n");
 500         SDL_DestroySemaphore(s);
 501         return 0;
 502     }
 503
 504     thread->stack = stack;
 505     thread->stack_size = stack_size;
 506     thread->name = name;
 507     thread->state = (flags & CREATE_THREAD_FROZEN) ?
 508         STATE_FROZEN : STATE_RUNNING;
 509     thread->context.start = function;
 510     thread->context.t = t;
 511     thread->context.s = s;
 512
 513     THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
 514                       thread - threads, THREAD_SDL_GET_NAME(thread));
 515
 516     return thread->id;
 517 }
 518
 519 void init_threads(void)
 520 {
 521     /* Main thread is already initialized */
 522     if (cores[CURRENT_CORE].running != &threads[0])
 523     {
 524         THREAD_PANICF("Wrong main thread in init_threads: %p\n",
 525                       cores[CURRENT_CORE].running);
 526     }
 527
 528     THREAD_SDL_DEBUGF("First Thread: %d (%s)\n",
 529             0, THREAD_SDL_GET_NAME(&threads[0]));
 530 }
 531
 532 #ifndef ALLOW_REMOVE_THREAD
 533 static void remove_thread(unsigned int thread_id)
 534 #else
 535 void remove_thread(unsigned int thread_id)
 536 #endif
 537 {
 538     struct thread_entry *current = cores[CURRENT_CORE].running;
 539     struct thread_entry *thread = thread_id_entry(thread_id);
 540
 541     SDL_Thread *t;
 542     SDL_sem *s;
 543
 544     if (thread_id != THREAD_ID_CURRENT && thread->id != thread_id)
 545         return;
 546
 547     int oldlevel = disable_irq_save();
 548
 549     t = thread->context.t;
 550     s = thread->context.s;
 551     thread->context.t = NULL;
 552
 553     if (thread != current)
 554     {
 555         switch (thread->state)
 556         {
 557         case STATE_BLOCKED:
 558         case STATE_BLOCKED_W_TMO:
 559             /* Remove thread from object it's waiting on */
 560             remove_from_list_l(thread->bqp, thread);
 561
 562 #ifdef HAVE_WAKEUP_EXT_CB
 563             if (thread->wakeup_ext_cb != NULL)
 564                 thread->wakeup_ext_cb(thread);
 565 #endif
 566             break;
 567         }
 568
 569         SDL_SemPost(s);
 570     }
 571
 572     THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
 573         thread - threads, THREAD_SDL_GET_NAME(thread));
 574
 575     new_thread_id(thread->id, thread);
 576     thread->state = STATE_KILLED;
 577     thread_queue_wake(&thread->queue);
 578
 579     SDL_DestroySemaphore(s);
 580
 581     if (thread == current)
 582     {
 583         /* Do a graceful exit - perform the longjmp back into the thread
 584            function to return */
 585         restore_irq(oldlevel);
 586         longjmp(thread_jmpbufs[current - threads], 1);
 587     }
 588
 589     SDL_KillThread(t);
 590     restore_irq(oldlevel);
 591 }
 592
 593 void thread_exit(void)
 594 {
 595     remove_thread(THREAD_ID_CURRENT);
 596 }
 597
 598 void thread_wait(unsigned int thread_id)
 599 {
 600     struct thread_entry *current = cores[CURRENT_CORE].running;
 601     struct thread_entry *thread = thread_id_entry(thread_id);
 602
 603     if (thread_id == THREAD_ID_CURRENT ||
 604         (thread->id == thread_id && thread->state != STATE_KILLED))
 605     {
 606         current->bqp = &thread->queue;
 607         block_thread(current);
 608         switch_thread();
 609     }
 610 }
 611
 612 int thread_stack_usage(const struct thread_entry *thread)
 613 {
 614     return 50;
 615     (void)thread;
 616 }
 617
 618 /* Return name if one or ID if none */
 619 void thread_get_name(char *buffer, int size,
 620                      struct thread_entry *thread)
 621 {
 622     if (size <= 0)
 623         return;
 624
 625     *buffer = '\0';
 626
 627     if (thread)
 628     {
 629         /* Display thread name if one or ID if none */
 630         bool named = thread->name && *thread->name;
 631         const char *fmt = named ? "%s" : "%08lX";
 632         intptr_t name = named ?
 633             (intptr_t)thread->name : (intptr_t)thread;
 634         snprintf(buffer, size, fmt, name);
 635     }
 636 }