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 volatile bool threads_exit = false;
  61
  62 extern long start_tick;
  63
  64 void thread_sdl_shutdown(void)
  65 {
  66     int i;
  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
  73     /* Do this before trying to acquire lock */
  74     threads_exit = true;
  75
  76     /* Take control */
  77     SDL_LockMutex(m);
  78
  79     for (i = 0; i < MAXTHREADS; i++)
  80     {
  81         struct thread_entry *thread = &threads[i];
  82         if (thread->context.t != NULL)
  83         {
  84             /* Signal thread on delay or block */
  85             SDL_Thread *t = thread->context.t;
  86             SDL_SemPost(thread->context.s);
  87             SDL_UnlockMutex(m);
  88             /* Wait for it to finish */
  89             SDL_WaitThread(t, NULL);
  90             /* Relock for next thread signal */
  91             SDL_LockMutex(m);
  92         }
  93     }
  94
  95     SDL_UnlockMutex(m);
  96     SDL_DestroyMutex(m);
  97 }
  98
  99 static void new_thread_id(unsigned int slot_num,
 100                           struct thread_entry *thread)
 101 {
 102     unsigned int version =
 103         (thread->id + (1u << THREAD_ID_VERSION_SHIFT))
 104             & THREAD_ID_VERSION_MASK;
 105
 106     if (version == 0)
 107         version = 1u << THREAD_ID_VERSION_SHIFT;
 108
 109     thread->id = version | (slot_num & THREAD_ID_SLOT_MASK);
 110 }
 111
 112 static struct thread_entry * find_empty_thread_slot(void)
 113 {
 114     struct thread_entry *thread = NULL;
 115     int n;
 116
 117     for (n = 0; n < MAXTHREADS; n++)
 118     {
 119         int state = threads[n].state;
 120
 121         if (state == STATE_KILLED)
 122         {
 123             thread = &threads[n];
 124             break;
 125         }
 126     }
 127
 128     return thread;
 129 }
 130
 131 /* Do main thread creation in this file scope to avoid the need to double-
 132    return to a prior call-level which would be unaware of the fact setjmp
 133    was used */
 134 extern void app_main(void *param);
 135 static int thread_sdl_app_main(void *param)
 136 {
 137     SDL_LockMutex(m);
 138     cores[CURRENT_CORE].running = &threads[0];
 139
 140     /* Set the jump address for return */
 141     if (setjmp(thread_jmpbufs[0]) == 0)
 142     {
 143         app_main(param);
 144         /* should not ever be reached but... */
 145         THREAD_PANICF("app_main returned!\n");
 146     }
 147
 148     /* Unlock and exit */
 149     SDL_UnlockMutex(m);
 150     return 0;
 151 }
 152
 153 /* Initialize SDL threading */
 154 bool thread_sdl_init(void *param)
 155 {
 156     struct thread_entry *thread;
 157     int n;
 158
 159     memset(cores, 0, sizeof(cores));
 160     memset(threads, 0, sizeof(threads));
 161
 162     m = SDL_CreateMutex();
 163
 164     if (SDL_LockMutex(m) == -1)
 165     {
 166         fprintf(stderr, "Couldn't lock mutex\n");
 167         return false;
 168     }
 169
 170     /* Initialize all IDs */
 171     for (n = 0; n < MAXTHREADS; n++)
 172         threads[n].id = THREAD_ID_INIT(n);
 173
 174     /* Slot 0 is reserved for the main thread - initialize it here and
 175        then create the SDL thread - it is possible to have a quick, early
 176        shutdown try to access the structure. */
 177     thread = &threads[0];
 178     thread->stack = (uintptr_t *)"       ";
 179     thread->stack_size = 8;
 180     thread->name = "main";
 181     thread->state = STATE_RUNNING;
 182     thread->context.s = SDL_CreateSemaphore(0);
 183     cores[CURRENT_CORE].running = thread;
 184
 185     if (thread->context.s == NULL)
 186     {
 187         fprintf(stderr, "Failed to create main semaphore\n");
 188         return false;
 189     }
 190
 191     thread->context.t = SDL_CreateThread(thread_sdl_app_main, param);
 192
 193     if (thread->context.t == NULL)
 194     {
 195         SDL_DestroySemaphore(thread->context.s);
 196         fprintf(stderr, "Failed to create main thread\n");
 197         return false;
 198     }
 199
 200     THREAD_SDL_DEBUGF("Main thread: %p\n", thread);
 201
 202     SDL_UnlockMutex(m);
 203     return true;
 204 }
 205
 206 void thread_sdl_exception_wait(void)
 207 {
 208     while (1)
 209     {
 210         SDL_Delay(HZ/10);
 211         if (threads_exit)
 212             thread_exit();
 213     }
 214 }
 215
 216 /* A way to yield and leave the threading system for extended periods */
 217 void thread_sdl_thread_lock(void *me)
 218 {
 219     SDL_LockMutex(m);
 220     cores[CURRENT_CORE].running = (struct thread_entry *)me;
 221
 222     if (threads_exit)
 223         thread_exit();
 224 }
 225
 226 void * thread_sdl_thread_unlock(void)
 227 {
 228     struct thread_entry *current = cores[CURRENT_CORE].running;
 229     SDL_UnlockMutex(m);
 230     return current;
 231 }
 232
 233 struct thread_entry * thread_id_entry(unsigned int thread_id)
 234 {
 235     return (thread_id == THREAD_ID_CURRENT) ?
 236         cores[CURRENT_CORE].running :
 237         &threads[thread_id & THREAD_ID_SLOT_MASK];
 238 }
 239
 240 static void add_to_list_l(struct thread_entry **list,
 241                           struct thread_entry *thread)
 242 {
 243     if (*list == NULL)
 244     {
 245         /* Insert into unoccupied list */
 246         thread->l.next = thread;
 247         thread->l.prev = thread;
 248         *list = thread;
 249     }
 250     else
 251     {
 252         /* Insert last */
 253         thread->l.next = *list;
 254         thread->l.prev = (*list)->l.prev;
 255         thread->l.prev->l.next = thread;
 256         (*list)->l.prev = thread;
 257     }
 258 }
 259
 260 static void remove_from_list_l(struct thread_entry **list,
 261                                struct thread_entry *thread)
 262 {
 263     if (thread == thread->l.next)
 264     {
 265         /* The only item */
 266         *list = NULL;
 267         return;
 268     }
 269
 270     if (thread == *list)
 271     {
 272         /* List becomes next item */
 273         *list = thread->l.next;
 274     }
 275
 276     /* Fix links to jump over the removed entry. */
 277     thread->l.prev->l.next = thread->l.next;
 278     thread->l.next->l.prev = thread->l.prev;
 279 }
 280
 281 unsigned int thread_get_current(void)
 282 {
 283     return cores[CURRENT_CORE].running->id;
 284 }
 285
 286 void switch_thread(void)
 287 {
 288     struct thread_entry *current = cores[CURRENT_CORE].running;
 289
 290     enable_irq();
 291
 292     switch (current->state)
 293     {
 294     case STATE_RUNNING:
 295     {
 296         SDL_UnlockMutex(m);
 297         /* Any other thread waiting already will get it first */
 298         SDL_LockMutex(m);
 299         break;
 300         } /* STATE_RUNNING: */
 301
 302     case STATE_BLOCKED:
 303     {
 304         int oldlevel;
 305
 306         SDL_UnlockMutex(m);
 307         SDL_SemWait(current->context.s);
 308         SDL_LockMutex(m);
 309
 310         oldlevel = disable_irq_save();
 311         current->state = STATE_RUNNING;
 312         restore_irq(oldlevel);
 313         break;
 314         } /* STATE_BLOCKED: */
 315
 316     case STATE_BLOCKED_W_TMO:
 317     {
 318         int result, oldlevel;
 319
 320         SDL_UnlockMutex(m);
 321         result = SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 322         SDL_LockMutex(m);
 323
 324         oldlevel = disable_irq_save();
 325
 326         if (current->state == STATE_BLOCKED_W_TMO)
 327         {
 328             /* Timed out */
 329             remove_from_list_l(current->bqp, current);
 330
 331 #ifdef HAVE_WAKEUP_EXT_CB
 332             if (current->wakeup_ext_cb != NULL)
 333                 current->wakeup_ext_cb(current);
 334 #endif
 335             current->state = STATE_RUNNING;
 336         }
 337
 338         if (result == SDL_MUTEX_TIMEDOUT)
 339         {
 340             /* Other signals from an explicit wake could have been made before
 341              * arriving here if we timed out waiting for the semaphore. Make
 342              * sure the count is reset. */
 343             while (SDL_SemValue(current->context.s) > 0)
 344                 SDL_SemTryWait(current->context.s);
 345         }
 346
 347         restore_irq(oldlevel);
 348         break;
 349         } /* STATE_BLOCKED_W_TMO: */
 350
 351     case STATE_SLEEPING:
 352     {
 353         SDL_UnlockMutex(m);
 354         SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 355         SDL_LockMutex(m);
 356         current->state = STATE_RUNNING;
 357         break;
 358         } /* STATE_SLEEPING: */
 359     }
 360
 361     cores[CURRENT_CORE].running = current;
 362
 363     if (threads_exit)
 364         thread_exit();
 365 }
 366
 367 void sleep_thread(int ticks)
 368 {
 369     struct thread_entry *current = cores[CURRENT_CORE].running;
 370     int rem;
 371
 372     current->state = STATE_SLEEPING;
 373
 374     rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
 375     if (rem < 0)
 376         rem = 0;
 377
 378     current->tmo_tick = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
 379 }
 380
 381 void block_thread(struct thread_entry *current)
 382 {
 383     current->state = STATE_BLOCKED;
 384     add_to_list_l(current->bqp, current);
 385 }
 386
 387 void block_thread_w_tmo(struct thread_entry *current, int ticks)
 388 {
 389     current->state = STATE_BLOCKED_W_TMO;
 390     current->tmo_tick = (1000/HZ)*ticks;
 391     add_to_list_l(current->bqp, current);
 392 }
 393
 394 unsigned int wakeup_thread(struct thread_entry **list)
 395 {
 396     struct thread_entry *thread = *list;
 397
 398     if (thread != NULL)
 399     {
 400         switch (thread->state)
 401         {
 402         case STATE_BLOCKED:
 403         case STATE_BLOCKED_W_TMO:
 404             remove_from_list_l(list, thread);
 405             thread->state = STATE_RUNNING;
 406             SDL_SemPost(thread->context.s);
 407             return THREAD_OK;
 408         }
 409     }
 410
 411     return THREAD_NONE;
 412 }
 413
 414 unsigned int thread_queue_wake(struct thread_entry **list)
 415 {
 416     unsigned int result = THREAD_NONE;
 417
 418     for (;;)
 419     {
 420         unsigned int rc = wakeup_thread(list);
 421
 422         if (rc == THREAD_NONE)
 423             break;
 424
 425         result |= rc;
 426     }
 427
 428     return result;
 429 }
 430
 431 void thread_thaw(unsigned int thread_id)
 432 {
 433     struct thread_entry *thread = thread_id_entry(thread_id);
 434
 435     if (thread->id == thread_id && thread->state == STATE_FROZEN)
 436     {
 437         thread->state = STATE_RUNNING;
 438         SDL_SemPost(thread->context.s);
 439     }
 440 }
 441
 442 int runthread(void *data)
 443 {
 444     struct thread_entry *current;
 445     jmp_buf *current_jmpbuf;
 446
 447     /* Cannot access thread variables before locking the mutex as the
 448        data structures may not be filled-in yet. */
 449     SDL_LockMutex(m);
 450     cores[CURRENT_CORE].running = (struct thread_entry *)data;
 451     current = cores[CURRENT_CORE].running;
 452     current_jmpbuf = &thread_jmpbufs[current - threads];
 453
 454     /* Setup jump for exit */
 455     if (setjmp(*current_jmpbuf) == 0)
 456     {
 457         /* Run the thread routine */
 458         if (current->state == STATE_FROZEN)
 459         {
 460             SDL_UnlockMutex(m);
 461             SDL_SemWait(current->context.s);
 462             SDL_LockMutex(m);
 463             cores[CURRENT_CORE].running = current;
 464         }
 465
 466         if (!threads_exit)
 467         {
 468             current->context.start();
 469             THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
 470                               current - threads, THREAD_SDL_GET_NAME(current));
 471             /* Thread routine returned - suicide */
 472         }
 473
 474         thread_exit();
 475     }
 476     else
 477     {
 478         /* Unlock and exit */
 479         SDL_UnlockMutex(m);
 480     }
 481
 482     return 0;
 483 }
 484
 485 unsigned int create_thread(void (*function)(void),
 486                            void* stack, size_t stack_size,
 487                            unsigned flags, const char *name)
 488 {
 489     struct thread_entry *thread;
 490     SDL_Thread* t;
 491     SDL_sem *s;
 492
 493     THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");
 494
 495     thread = find_empty_thread_slot();
 496     if (thread == NULL)
 497     {
 498         DEBUGF("Failed to find thread slot\n");
 499         return 0;
 500     }
 501
 502     s = SDL_CreateSemaphore(0);
 503     if (s == NULL)
 504     {
 505         DEBUGF("Failed to create semaphore\n");
 506         return 0;
 507     }
 508
 509     t = SDL_CreateThread(runthread, thread);
 510     if (t == NULL)
 511     {
 512         DEBUGF("Failed to create SDL thread\n");
 513         SDL_DestroySemaphore(s);
 514         return 0;
 515     }
 516
 517     thread->stack = stack;
 518     thread->stack_size = stack_size;
 519     thread->name = name;
 520     thread->state = (flags & CREATE_THREAD_FROZEN) ?
 521         STATE_FROZEN : STATE_RUNNING;
 522     thread->context.start = function;
 523     thread->context.t = t;
 524     thread->context.s = s;
 525
 526     THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
 527                       thread - threads, THREAD_SDL_GET_NAME(thread));
 528
 529     return thread->id;
 530 }
 531
 532 void init_threads(void)
 533 {
 534     /* Main thread is already initialized */
 535     if (cores[CURRENT_CORE].running != &threads[0])
 536     {
 537         THREAD_PANICF("Wrong main thread in init_threads: %p\n",
 538                       cores[CURRENT_CORE].running);
 539     }
 540
 541     THREAD_SDL_DEBUGF("First Thread: %d (%s)\n",
 542             0, THREAD_SDL_GET_NAME(&threads[0]));
 543 }
 544
 545 #ifndef ALLOW_REMOVE_THREAD
 546 static void remove_thread(unsigned int thread_id)
 547 #else
 548 void remove_thread(unsigned int thread_id)
 549 #endif
 550 {
 551     struct thread_entry *current = cores[CURRENT_CORE].running;
 552     struct thread_entry *thread = thread_id_entry(thread_id);
 553
 554     SDL_Thread *t;
 555     SDL_sem *s;
 556
 557     if (thread_id != THREAD_ID_CURRENT && thread->id != thread_id)
 558         return;
 559
 560     int oldlevel = disable_irq_save();
 561
 562     t = thread->context.t;
 563     s = thread->context.s;
 564     thread->context.t = NULL;
 565
 566     if (thread != current)
 567     {
 568         switch (thread->state)
 569         {
 570         case STATE_BLOCKED:
 571         case STATE_BLOCKED_W_TMO:
 572             /* Remove thread from object it's waiting on */
 573             remove_from_list_l(thread->bqp, thread);
 574
 575 #ifdef HAVE_WAKEUP_EXT_CB
 576             if (thread->wakeup_ext_cb != NULL)
 577                 thread->wakeup_ext_cb(thread);
 578 #endif
 579             break;
 580         }
 581
 582         SDL_SemPost(s);
 583     }
 584
 585     THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
 586         thread - threads, THREAD_SDL_GET_NAME(thread));
 587
 588     new_thread_id(thread->id, thread);
 589     thread->state = STATE_KILLED;
 590     thread_queue_wake(&thread->queue);
 591
 592     SDL_DestroySemaphore(s);
 593
 594     if (thread == current)
 595     {
 596         /* Do a graceful exit - perform the longjmp back into the thread
 597            function to return */
 598         restore_irq(oldlevel);
 599         longjmp(thread_jmpbufs[current - threads], 1);
 600     }
 601
 602     SDL_KillThread(t);
 603     restore_irq(oldlevel);
 604 }
 605
 606 void thread_exit(void)
 607 {
 608     remove_thread(THREAD_ID_CURRENT);
 609 }
 610
 611 void thread_wait(unsigned int thread_id)
 612 {
 613     struct thread_entry *current = cores[CURRENT_CORE].running;
 614     struct thread_entry *thread = thread_id_entry(thread_id);
 615
 616     if (thread_id == THREAD_ID_CURRENT ||
 617         (thread->id == thread_id && thread->state != STATE_KILLED))
 618     {
 619         current->bqp = &thread->queue;
 620         block_thread(current);
 621         switch_thread();
 622     }
 623 }
 624
 625 int thread_stack_usage(const struct thread_entry *thread)
 626 {
 627     return 50;
 628     (void)thread;
 629 }
 630
 631 /* Return name if one or ID if none */
 632 void thread_get_name(char *buffer, int size,
 633                      struct thread_entry *thread)
 634 {
 635     if (size <= 0)
 636         return;
 637
 638     *buffer = '\0';
 639
 640     if (thread)
 641     {
 642         /* Display thread name if one or ID if none */
 643         bool named = thread->name && *thread->name;
 644         const char *fmt = named ? "%s" : "%08lX";
 645         intptr_t name = named ?
 646             (intptr_t)thread->name : (intptr_t)thread;
 647         snprintf(buffer, size, fmt, name);
 648     }
 649 }