firmware/target/hosted/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 static 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 /* this mutex locks out other Rockbox threads while one runs,
  60  * that enables us to simulate a cooperative environment even if
  61  * the host is preemptive */
  62 static SDL_mutex *m;
  63 static volatile bool threads_exit = false;
  64
  65 extern long start_tick;
  66
  67 void sim_thread_shutdown(void)
  68 {
  69     int i;
  70
  71     /* Tell all threads jump back to their start routines, unlock and exit
  72        gracefully - we'll check each one in turn for it's status. Threads
  73        _could_ terminate via remove_thread or multiple threads could exit
  74        on each unlock but that is safe. */
  75
  76     /* Do this before trying to acquire lock */
  77     threads_exit = true;
  78
  79     /* Take control */
  80     SDL_LockMutex(m);
  81
  82     for (i = 0; i < MAXTHREADS; i++)
  83     {
  84         struct thread_entry *thread = &threads[i];
  85         /* exit all current threads, except the main one */
  86         if (thread->context.t != NULL)
  87         {
  88             /* Signal thread on delay or block */
  89             SDL_Thread *t = thread->context.t;
  90             SDL_SemPost(thread->context.s);
  91             SDL_UnlockMutex(m);
  92             /* Wait for it to finish */
  93             SDL_WaitThread(t, NULL);
  94             /* Relock for next thread signal */
  95             SDL_LockMutex(m);
  96         }
  97     }
  98
  99     SDL_UnlockMutex(m);
 100     SDL_DestroyMutex(m);
 101 }
 102
 103 static void new_thread_id(unsigned int slot_num,
 104                           struct thread_entry *thread)
 105 {
 106     unsigned int version =
 107         (thread->id + (1u << THREAD_ID_VERSION_SHIFT))
 108             & THREAD_ID_VERSION_MASK;
 109
 110     if (version == 0)
 111         version = 1u << THREAD_ID_VERSION_SHIFT;
 112
 113     thread->id = version | (slot_num & THREAD_ID_SLOT_MASK);
 114 }
 115
 116 static struct thread_entry * find_empty_thread_slot(void)
 117 {
 118     struct thread_entry *thread = NULL;
 119     int n;
 120
 121     for (n = 0; n < MAXTHREADS; n++)
 122     {
 123         int state = threads[n].state;
 124
 125         if (state == STATE_KILLED)
 126         {
 127             thread = &threads[n];
 128             break;
 129         }
 130     }
 131
 132     return thread;
 133 }
 134
 135
 136 /* Initialize SDL threading */
 137 void init_threads(void)
 138 {
 139     struct thread_entry *thread;
 140     int n;
 141
 142     memset(cores, 0, sizeof(cores));
 143     memset(threads, 0, sizeof(threads));
 144
 145     m = SDL_CreateMutex();
 146
 147     if (SDL_LockMutex(m) == -1)
 148     {
 149         fprintf(stderr, "Couldn't lock mutex\n");
 150         return;
 151     }
 152
 153     /* Initialize all IDs */
 154     for (n = 0; n < MAXTHREADS; n++)
 155         threads[n].id = THREAD_ID_INIT(n);
 156
 157     /* Slot 0 is reserved for the main thread - initialize it here and
 158        then create the SDL thread - it is possible to have a quick, early
 159        shutdown try to access the structure. */
 160     thread = &threads[0];
 161     thread->stack = (uintptr_t *)"       ";
 162     thread->stack_size = 8;
 163     thread->name = "main";
 164     thread->state = STATE_RUNNING;
 165     thread->context.s = SDL_CreateSemaphore(0);
 166     thread->context.t = NULL; /* NULL for the implicit main thread */
 167     cores[CURRENT_CORE].running = thread;
 168
 169     if (thread->context.s == NULL)
 170     {
 171         fprintf(stderr, "Failed to create main semaphore\n");
 172         return;
 173     }
 174
 175     THREAD_SDL_DEBUGF("Main thread: %p\n", thread);
 176
 177     return;
 178 }
 179
 180 void sim_thread_exception_wait(void)
 181 {
 182     while (1)
 183     {
 184         SDL_Delay(HZ/10);
 185         if (threads_exit)
 186             thread_exit();
 187     }
 188 }
 189
 190 /* A way to yield and leave the threading system for extended periods */
 191 void sim_thread_lock(void *me)
 192 {
 193     SDL_LockMutex(m);
 194     cores[CURRENT_CORE].running = (struct thread_entry *)me;
 195
 196     if (threads_exit)
 197         thread_exit();
 198 }
 199
 200 void * sim_thread_unlock(void)
 201 {
 202     struct thread_entry *current = cores[CURRENT_CORE].running;
 203     SDL_UnlockMutex(m);
 204     return current;
 205 }
 206
 207 struct thread_entry * thread_id_entry(unsigned int thread_id)
 208 {
 209     return (thread_id == THREAD_ID_CURRENT) ?
 210         cores[CURRENT_CORE].running :
 211         &threads[thread_id & THREAD_ID_SLOT_MASK];
 212 }
 213
 214 static void add_to_list_l(struct thread_entry **list,
 215                           struct thread_entry *thread)
 216 {
 217     if (*list == NULL)
 218     {
 219         /* Insert into unoccupied list */
 220         thread->l.next = thread;
 221         thread->l.prev = thread;
 222         *list = thread;
 223     }
 224     else
 225     {
 226         /* Insert last */
 227         thread->l.next = *list;
 228         thread->l.prev = (*list)->l.prev;
 229         thread->l.prev->l.next = thread;
 230         (*list)->l.prev = thread;
 231     }
 232 }
 233
 234 static void remove_from_list_l(struct thread_entry **list,
 235                                struct thread_entry *thread)
 236 {
 237     if (thread == thread->l.next)
 238     {
 239         /* The only item */
 240         *list = NULL;
 241         return;
 242     }
 243
 244     if (thread == *list)
 245     {
 246         /* List becomes next item */
 247         *list = thread->l.next;
 248     }
 249
 250     /* Fix links to jump over the removed entry. */
 251     thread->l.prev->l.next = thread->l.next;
 252     thread->l.next->l.prev = thread->l.prev;
 253 }
 254
 255 unsigned int thread_get_current(void)
 256 {
 257     return cores[CURRENT_CORE].running->id;
 258 }
 259
 260 void switch_thread(void)
 261 {
 262     struct thread_entry *current = cores[CURRENT_CORE].running;
 263
 264     enable_irq();
 265
 266     switch (current->state)
 267     {
 268     case STATE_RUNNING:
 269     {
 270         SDL_UnlockMutex(m);
 271         /* Any other thread waiting already will get it first */
 272         SDL_LockMutex(m);
 273         break;
 274         } /* STATE_RUNNING: */
 275
 276     case STATE_BLOCKED:
 277     {
 278         int oldlevel;
 279
 280         SDL_UnlockMutex(m);
 281         SDL_SemWait(current->context.s);
 282         SDL_LockMutex(m);
 283
 284         oldlevel = disable_irq_save();
 285         current->state = STATE_RUNNING;
 286         restore_irq(oldlevel);
 287         break;
 288         } /* STATE_BLOCKED: */
 289
 290     case STATE_BLOCKED_W_TMO:
 291     {
 292         int result, oldlevel;
 293
 294         SDL_UnlockMutex(m);
 295         result = SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 296         SDL_LockMutex(m);
 297
 298         oldlevel = disable_irq_save();
 299
 300         if (current->state == STATE_BLOCKED_W_TMO)
 301         {
 302             /* Timed out */
 303             remove_from_list_l(current->bqp, current);
 304
 305 #ifdef HAVE_WAKEUP_EXT_CB
 306             if (current->wakeup_ext_cb != NULL)
 307                 current->wakeup_ext_cb(current);
 308 #endif
 309             current->state = STATE_RUNNING;
 310         }
 311
 312         if (result == SDL_MUTEX_TIMEDOUT)
 313         {
 314             /* Other signals from an explicit wake could have been made before
 315              * arriving here if we timed out waiting for the semaphore. Make
 316              * sure the count is reset. */
 317             while (SDL_SemValue(current->context.s) > 0)
 318                 SDL_SemTryWait(current->context.s);
 319         }
 320
 321         restore_irq(oldlevel);
 322         break;
 323         } /* STATE_BLOCKED_W_TMO: */
 324
 325     case STATE_SLEEPING:
 326     {
 327         SDL_UnlockMutex(m);
 328         SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
 329         SDL_LockMutex(m);
 330         current->state = STATE_RUNNING;
 331         break;
 332         } /* STATE_SLEEPING: */
 333     }
 334
 335     cores[CURRENT_CORE].running = current;
 336
 337     if (threads_exit)
 338         thread_exit();
 339 }
 340
 341 void sleep_thread(int ticks)
 342 {
 343     struct thread_entry *current = cores[CURRENT_CORE].running;
 344     int rem;
 345
 346     current->state = STATE_SLEEPING;
 347
 348     rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
 349     if (rem < 0)
 350         rem = 0;
 351
 352     current->tmo_tick = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
 353 }
 354
 355 void block_thread(struct thread_entry *current)
 356 {
 357     current->state = STATE_BLOCKED;
 358     add_to_list_l(current->bqp, current);
 359 }
 360
 361 void block_thread_w_tmo(struct thread_entry *current, int ticks)
 362 {
 363     current->state = STATE_BLOCKED_W_TMO;
 364     current->tmo_tick = (1000/HZ)*ticks;
 365     add_to_list_l(current->bqp, current);
 366 }
 367
 368 unsigned int wakeup_thread(struct thread_entry **list)
 369 {
 370     struct thread_entry *thread = *list;
 371
 372     if (thread != NULL)
 373     {
 374         switch (thread->state)
 375         {
 376         case STATE_BLOCKED:
 377         case STATE_BLOCKED_W_TMO:
 378             remove_from_list_l(list, thread);
 379             thread->state = STATE_RUNNING;
 380             SDL_SemPost(thread->context.s);
 381             return THREAD_OK;
 382         }
 383     }
 384
 385     return THREAD_NONE;
 386 }
 387
 388 unsigned int thread_queue_wake(struct thread_entry **list)
 389 {
 390     unsigned int result = THREAD_NONE;
 391
 392     for (;;)
 393     {
 394         unsigned int rc = wakeup_thread(list);
 395
 396         if (rc == THREAD_NONE)
 397             break;
 398
 399         result |= rc;
 400     }
 401
 402     return result;
 403 }
 404
 405 void thread_thaw(unsigned int thread_id)
 406 {
 407     struct thread_entry *thread = thread_id_entry(thread_id);
 408
 409     if (thread->id == thread_id && thread->state == STATE_FROZEN)
 410     {
 411         thread->state = STATE_RUNNING;
 412         SDL_SemPost(thread->context.s);
 413     }
 414 }
 415
 416 int runthread(void *data)
 417 {
 418     struct thread_entry *current;
 419     jmp_buf *current_jmpbuf;
 420
 421     /* Cannot access thread variables before locking the mutex as the
 422        data structures may not be filled-in yet. */
 423     SDL_LockMutex(m);
 424     cores[CURRENT_CORE].running = (struct thread_entry *)data;
 425     current = cores[CURRENT_CORE].running;
 426     current_jmpbuf = &thread_jmpbufs[current - threads];
 427
 428     /* Setup jump for exit */
 429     if (setjmp(*current_jmpbuf) == 0)
 430     {
 431         /* Run the thread routine */
 432         if (current->state == STATE_FROZEN)
 433         {
 434             SDL_UnlockMutex(m);
 435             SDL_SemWait(current->context.s);
 436             SDL_LockMutex(m);
 437             cores[CURRENT_CORE].running = current;
 438         }
 439
 440         if (!threads_exit)
 441         {
 442             current->context.start();
 443             THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
 444                               current - threads, THREAD_SDL_GET_NAME(current));
 445             /* Thread routine returned - suicide */
 446         }
 447
 448         thread_exit();
 449     }
 450     else
 451     {
 452         /* Unlock and exit */
 453         SDL_UnlockMutex(m);
 454     }
 455
 456     return 0;
 457 }
 458
 459 unsigned int create_thread(void (*function)(void),
 460                            void* stack, size_t stack_size,
 461                            unsigned flags, const char *name)
 462 {
 463     struct thread_entry *thread;
 464     SDL_Thread* t;
 465     SDL_sem *s;
 466
 467     THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");
 468
 469     thread = find_empty_thread_slot();
 470     if (thread == NULL)
 471     {
 472         DEBUGF("Failed to find thread slot\n");
 473         return 0;
 474     }
 475
 476     s = SDL_CreateSemaphore(0);
 477     if (s == NULL)
 478     {
 479         DEBUGF("Failed to create semaphore\n");
 480         return 0;
 481     }
 482
 483     t = SDL_CreateThread(runthread, thread);
 484     if (t == NULL)
 485     {
 486         DEBUGF("Failed to create SDL thread\n");
 487         SDL_DestroySemaphore(s);
 488         return 0;
 489     }
 490
 491     thread->stack = stack;
 492     thread->stack_size = stack_size;
 493     thread->name = name;
 494     thread->state = (flags & CREATE_THREAD_FROZEN) ?
 495         STATE_FROZEN : STATE_RUNNING;
 496     thread->context.start = function;
 497     thread->context.t = t;
 498     thread->context.s = s;
 499
 500     THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
 501                       thread - threads, THREAD_SDL_GET_NAME(thread));
 502
 503     return thread->id;
 504 }
 505
 506 #ifndef ALLOW_REMOVE_THREAD
 507 static void remove_thread(unsigned int thread_id)
 508 #else
 509 void remove_thread(unsigned int thread_id)
 510 #endif
 511 {
 512     struct thread_entry *current = cores[CURRENT_CORE].running;
 513     struct thread_entry *thread = thread_id_entry(thread_id);
 514
 515     SDL_Thread *t;
 516     SDL_sem *s;
 517
 518     if (thread_id != THREAD_ID_CURRENT && thread->id != thread_id)
 519         return;
 520
 521     int oldlevel = disable_irq_save();
 522
 523     t = thread->context.t;
 524     s = thread->context.s;
 525     thread->context.t = NULL;
 526
 527     if (thread != current)
 528     {
 529         switch (thread->state)
 530         {
 531         case STATE_BLOCKED:
 532         case STATE_BLOCKED_W_TMO:
 533             /* Remove thread from object it's waiting on */
 534             remove_from_list_l(thread->bqp, thread);
 535
 536 #ifdef HAVE_WAKEUP_EXT_CB
 537             if (thread->wakeup_ext_cb != NULL)
 538                 thread->wakeup_ext_cb(thread);
 539 #endif
 540             break;
 541         }
 542
 543         SDL_SemPost(s);
 544     }
 545
 546     THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
 547         thread - threads, THREAD_SDL_GET_NAME(thread));
 548
 549     new_thread_id(thread->id, thread);
 550     thread->state = STATE_KILLED;
 551     thread_queue_wake(&thread->queue);
 552
 553     SDL_DestroySemaphore(s);
 554
 555     if (thread == current)
 556     {
 557         /* Do a graceful exit - perform the longjmp back into the thread
 558            function to return */
 559         restore_irq(oldlevel);
 560         longjmp(thread_jmpbufs[current - threads], 1);
 561     }
 562
 563     SDL_KillThread(t);
 564     restore_irq(oldlevel);
 565 }
 566
 567 void thread_exit(void)
 568 {
 569     remove_thread(THREAD_ID_CURRENT);
 570 }
 571
 572 void thread_wait(unsigned int thread_id)
 573 {
 574     struct thread_entry *current = cores[CURRENT_CORE].running;
 575     struct thread_entry *thread = thread_id_entry(thread_id);
 576
 577     if (thread_id == THREAD_ID_CURRENT ||
 578         (thread->id == thread_id && thread->state != STATE_KILLED))
 579     {
 580         current->bqp = &thread->queue;
 581         block_thread(current);
 582         switch_thread();
 583     }
 584 }
 585
 586 int thread_stack_usage(const struct thread_entry *thread)
 587 {
 588     return 50;
 589     (void)thread;
 590 }
 591
 592 /* Return name if one or ID if none */
 593 void thread_get_name(char *buffer, int size,
 594                      struct thread_entry *thread)
 595 {
 596     if (size <= 0)
 597         return;
 598
 599     *buffer = '\0';
 600
 601     if (thread)
 602     {
 603         /* Display thread name if one or ID if none */
 604         bool named = thread->name && *thread->name;
 605         const char *fmt = named ? "%s" : "%08lX";
 606         intptr_t name = named ?
 607             (intptr_t)thread->name : (intptr_t)thread;
 608         snprintf(buffer, size, fmt, name);
 609     }
 610 }