summaryrefslogtreecommitdiffstats
path: root/uisimulator/sdl/thread-sdl.c
blob: ab1086dd7d8733b00e84e28efa8090a518b1bd03 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2006 Dan Everton
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <stdbool.h>
#include <time.h>
#include <SDL.h>
#include <SDL_thread.h>
#include <stdlib.h>
#include <memory.h>
#include <setjmp.h>
#include "system-sdl.h"
#include "thread-sdl.h"
#include "system.h"
#include "kernel.h"
#include "thread.h"
#include "debug.h"

/* Define this as 1 to show informational messages that are not errors. */
#define THREAD_SDL_DEBUGF_ENABLED 0

#if THREAD_SDL_DEBUGF_ENABLED
#define THREAD_SDL_DEBUGF(...) DEBUGF(__VA_ARGS__)
static char __name[32];
#define THREAD_SDL_GET_NAME(thread) \
    ({ thread_get_name(__name, ARRAYLEN(__name), thread); __name; })
#else
#define THREAD_SDL_DEBUGF(...)
#define THREAD_SDL_GET_NAME(thread)
#endif

#define THREAD_PANICF(str...) \
    ({ fprintf(stderr, str); exit(-1); })

/* Thread/core entries as in rockbox core */
struct core_entry cores[NUM_CORES];
struct thread_entry threads[MAXTHREADS];
/* Jump buffers for graceful exit - kernel threads don't stay neatly
 * in their start routines responding to messages so this is the only
 * way to get them back in there so they may exit */
static jmp_buf thread_jmpbufs[MAXTHREADS];
static SDL_mutex *m;
static bool threads_exit = false;

extern long start_tick;

void thread_sdl_shutdown(void)
{
    int i;
    /* Take control */
    SDL_LockMutex(m);

    /* Tell all threads jump back to their start routines, unlock and exit
       gracefully - we'll check each one in turn for it's status. Threads
       _could_ terminate via remove_thread or multiple threads could exit
       on each unlock but that is safe. */
    threads_exit = true;

    for (i = 0; i < MAXTHREADS; i++)
    {
        struct thread_entry *thread = &threads[i];
        if (thread->context.t != NULL)
        {
            /* Signal thread on delay or block */
            SDL_Thread *t = thread->context.t;
            SDL_SemPost(thread->context.s);
            SDL_UnlockMutex(m);
            /* Wait for it to finish */
            SDL_WaitThread(t, NULL);
            /* Relock for next thread signal */
            SDL_LockMutex(m);
        }        
    }

    SDL_UnlockMutex(m);
    SDL_DestroyMutex(m);
}

static void new_thread_id(unsigned int slot_num,
                          struct thread_entry *thread)
{
    unsigned int version =
        (thread->id + (1u << THREAD_ID_VERSION_SHIFT))
            & THREAD_ID_VERSION_MASK;

    if (version == 0)
        version = 1u << THREAD_ID_VERSION_SHIFT;

    thread->id = version | (slot_num & THREAD_ID_SLOT_MASK);
}

static struct thread_entry * find_empty_thread_slot(void)
{
    struct thread_entry *thread = NULL;
    int n;

    for (n = 0; n < MAXTHREADS; n++)
    {
        int state = threads[n].state;

        if (state == STATE_KILLED)
        {
            thread = &threads[n];
            break;
        }
    }

    return thread;
}

/* Do main thread creation in this file scope to avoid the need to double-
   return to a prior call-level which would be unaware of the fact setjmp
   was used */
extern void app_main(void *param);
static int thread_sdl_app_main(void *param)
{
    SDL_LockMutex(m);
    cores[CURRENT_CORE].running = &threads[0];

    /* Set the jump address for return */
    if (setjmp(thread_jmpbufs[0]) == 0)
    {
        app_main(param);
        /* should not ever be reached but... */
        THREAD_PANICF("app_main returned!\n");
    }

    /* Unlock and exit */
    SDL_UnlockMutex(m);
    return 0;
}

/* Initialize SDL threading */
bool thread_sdl_init(void *param)
{
    struct thread_entry *thread;
    int n;

    memset(cores, 0, sizeof(cores));
    memset(threads, 0, sizeof(threads));

    m = SDL_CreateMutex();

    if (SDL_LockMutex(m) == -1)
    {
        fprintf(stderr, "Couldn't lock mutex\n");
        return false;
    }

    /* Initialize all IDs */
    for (n = 0; n < MAXTHREADS; n++)
        threads[n].id = THREAD_ID_INIT(n);

    /* Slot 0 is reserved for the main thread - initialize it here and
       then create the SDL thread - it is possible to have a quick, early
       shutdown try to access the structure. */
    thread = &threads[0];
    thread->stack = (uintptr_t *)"       ";
    thread->stack_size = 8;
    thread->name = "main";
    thread->state = STATE_RUNNING;
    thread->context.s = SDL_CreateSemaphore(0);
    cores[CURRENT_CORE].running = thread;
 
    if (thread->context.s == NULL)
    {
        fprintf(stderr, "Failed to create main semaphore\n");
        return false;
    }

    thread->context.t = SDL_CreateThread(thread_sdl_app_main, param);

    if (thread->context.t == NULL)
    {
        SDL_DestroySemaphore(thread->context.s);
        fprintf(stderr, "Failed to create main thread\n");
        return false;
    }

    THREAD_SDL_DEBUGF("Main thread: %p\n", thread);

    SDL_UnlockMutex(m);
    return true;
}

/* A way to yield and leave the threading system for extended periods */
void thread_sdl_thread_lock(void *me)
{
    SDL_LockMutex(m);
    cores[CURRENT_CORE].running = (struct thread_entry *)me;

    if (threads_exit)
        thread_exit();
}

void * thread_sdl_thread_unlock(void)
{
    struct thread_entry *current = cores[CURRENT_CORE].running;
    SDL_UnlockMutex(m);
    return current;
}

struct thread_entry * thread_id_entry(unsigned int thread_id)
{
    return (thread_id == THREAD_ID_CURRENT) ? 
        cores[CURRENT_CORE].running :
        &threads[thread_id & THREAD_ID_SLOT_MASK];
}

static void add_to_list_l(struct thread_entry **list,
                          struct thread_entry *thread)
{
    if (*list == NULL)
    {
        /* Insert into unoccupied list */
        thread->l.next = thread;
        thread->l.prev = thread;
        *list = thread;
    }
    else
    {
        /* Insert last */
        thread->l.next = *list;
        thread->l.prev = (*list)->l.prev;
        thread->l.prev->l.next = thread;
        (*list)->l.prev = thread;
    }
}

static void remove_from_list_l(struct thread_entry **list,
                               struct thread_entry *thread)
{
    if (thread == thread->l.next)
    {
        /* The only item */
        *list = NULL;
        return;
    }

    if (thread == *list)
    {
        /* List becomes next item */
        *list = thread->l.next;
    }

    /* Fix links to jump over the removed entry. */
    thread->l.prev->l.next = thread->l.next;
    thread->l.next->l.prev = thread->l.prev;
}

unsigned int thread_get_current(void)
{
    return cores[CURRENT_CORE].running->id;
}

void switch_thread(void)
{
    struct thread_entry *current = cores[CURRENT_CORE].running;

    enable_irq();

    switch (current->state)
    {
    case STATE_RUNNING:
    {
        SDL_UnlockMutex(m);
        /* Any other thread waiting already will get it first */
        SDL_LockMutex(m);
        break;
        } /* STATE_RUNNING: */

    case STATE_BLOCKED:
    {
        int oldlevel;

        SDL_UnlockMutex(m);
        SDL_SemWait(current->context.s);
        SDL_LockMutex(m);

        oldlevel = disable_irq_save();
        current->state = STATE_RUNNING;
        restore_irq(oldlevel);
        break;
        } /* STATE_BLOCKED: */

    case STATE_BLOCKED_W_TMO:
    {
        int result, oldlevel;

        SDL_UnlockMutex(m);
        result = SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
        SDL_LockMutex(m);

        oldlevel = disable_irq_save();

        if (current->state == STATE_BLOCKED_W_TMO)
        {
            /* Timed out */
            remove_from_list_l(current->bqp, current);

#ifdef HAVE_WAKEUP_EXT_CB
            if (current->wakeup_ext_cb != NULL)
                current->wakeup_ext_cb(current);
#endif
            current->state = STATE_RUNNING;
        }

        if (result == SDL_MUTEX_TIMEDOUT)
        {
            /* Other signals from an explicit wake could have been made before
             * arriving here if we timed out waiting for the semaphore. Make
             * sure the count is reset. */
            while (SDL_SemValue(current->context.s) > 0)
                SDL_SemTryWait(current->context.s);
        }

        restore_irq(oldlevel);
        break;
        } /* STATE_BLOCKED_W_TMO: */

    case STATE_SLEEPING:
    {
        SDL_UnlockMutex(m);
        SDL_SemWaitTimeout(current->context.s, current->tmo_tick);
        SDL_LockMutex(m);
        current->state = STATE_RUNNING;
        break;
        } /* STATE_SLEEPING: */
    }

    cores[CURRENT_CORE].running = current;

    if (threads_exit)
        thread_exit();
}

void sleep_thread(int ticks)
{
    struct thread_entry *current = cores[CURRENT_CORE].running;
    int rem;

    current->state = STATE_SLEEPING;

    rem = (SDL_GetTicks() - start_tick) % (1000/HZ);
    if (rem < 0)
        rem = 0;

    current->tmo_tick = (1000/HZ) * ticks + ((1000/HZ)-1) - rem;
}

void block_thread(struct thread_entry *current)
{
    current->state = STATE_BLOCKED;
    add_to_list_l(current->bqp, current);
}

void block_thread_w_tmo(struct thread_entry *current, int ticks)
{
    current->state = STATE_BLOCKED_W_TMO;
    current->tmo_tick = (1000/HZ)*ticks;
    add_to_list_l(current->bqp, current);
}

unsigned int wakeup_thread(struct thread_entry **list)
{
    struct thread_entry *thread = *list;

    if (thread != NULL)
    {
        switch (thread->state)
        {
        case STATE_BLOCKED:
        case STATE_BLOCKED_W_TMO:
            remove_from_list_l(list, thread);
            thread->state = STATE_RUNNING;
            SDL_SemPost(thread->context.s);
            return THREAD_OK;
        }
    }

    return THREAD_NONE;
}

unsigned int thread_queue_wake(struct thread_entry **list)
{
    unsigned int result = THREAD_NONE;

    for (;;)
    {
        unsigned int rc = wakeup_thread(list);

        if (rc == THREAD_NONE)
            break;

        result |= rc;        
    }

    return result;
}

void thread_thaw(unsigned int thread_id)
{
    struct thread_entry *thread = thread_id_entry(thread_id);

    if (thread->id == thread_id && thread->state == STATE_FROZEN)
    {
        thread->state = STATE_RUNNING;
        SDL_SemPost(thread->context.s);
    }
}

int runthread(void *data)
{
    struct thread_entry *current;
    jmp_buf *current_jmpbuf;

    /* Cannot access thread variables before locking the mutex as the
       data structures may not be filled-in yet. */
    SDL_LockMutex(m);
    cores[CURRENT_CORE].running = (struct thread_entry *)data;
    current = cores[CURRENT_CORE].running;
    current_jmpbuf = &thread_jmpbufs[current - threads];

    /* Setup jump for exit */
    if (setjmp(*current_jmpbuf) == 0)
    {
        /* Run the thread routine */
        if (current->state == STATE_FROZEN)
        {
            SDL_UnlockMutex(m);
            SDL_SemWait(current->context.s);
            SDL_LockMutex(m);
            cores[CURRENT_CORE].running = current;
        }

        if (!threads_exit)
        {
            current->context.start();
            THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
                              current - threads, THREAD_SDL_GET_NAME(current));
            /* Thread routine returned - suicide */
        }

        thread_exit();
    }
    else
    {
        /* Unlock and exit */
        SDL_UnlockMutex(m);
    }

    return 0;
}

unsigned int create_thread(void (*function)(void),
                           void* stack, size_t stack_size,
                           unsigned flags, const char *name)
{
    struct thread_entry *thread;
    SDL_Thread* t;
    SDL_sem *s;

    THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");

    thread = find_empty_thread_slot();
    if (thread == NULL)
    {
        DEBUGF("Failed to find thread slot\n");
        return 0;
    }

    s = SDL_CreateSemaphore(0);
    if (s == NULL)
    {
        DEBUGF("Failed to create semaphore\n");
        return 0;
    }

    t = SDL_CreateThread(runthread, thread);
    if (t == NULL)
    {
        DEBUGF("Failed to create SDL thread\n");
        SDL_DestroySemaphore(s);
        return 0;
    }

    thread->stack = stack;
    thread->stack_size = stack_size;
    thread->name = name;
    thread->state = (flags & CREATE_THREAD_FROZEN) ?
        STATE_FROZEN : STATE_RUNNING;
    thread->context.start = function;
    thread->context.t = t;
    thread->context.s = s;

    THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
                      thread - threads, THREAD_SDL_GET_NAME(thread));

    return thread->id;
}

void init_threads(void)
{
    /* Main thread is already initialized */
    if (cores[CURRENT_CORE].running != &threads[0])
    {
        THREAD_PANICF("Wrong main thread in init_threads: %p\n",
                      cores[CURRENT_CORE].running);
    }

    THREAD_SDL_DEBUGF("First Thread: %d (%s)\n",
            0, THREAD_SDL_GET_NAME(&threads[0]));
}

#ifndef ALLOW_REMOVE_THREAD
static void remove_thread(unsigned int thread_id)
#else
void remove_thread(unsigned int thread_id)
#endif
{
    struct thread_entry *current = cores[CURRENT_CORE].running;
    struct thread_entry *thread = thread_id_entry(thread_id);

    SDL_Thread *t;
    SDL_sem *s;

    if (thread_id != THREAD_ID_CURRENT && thread->id != thread_id)
        return;

    int oldlevel = disable_irq_save();

    t = thread->context.t;
    s = thread->context.s;
    thread->context.t = NULL;

    if (thread != current)
    {
        switch (thread->state)
        {
        case STATE_BLOCKED:
        case STATE_BLOCKED_W_TMO:
            /* Remove thread from object it's waiting on */
            remove_from_list_l(thread->bqp, thread);

#ifdef HAVE_WAKEUP_EXT_CB
            if (thread->wakeup_ext_cb != NULL)
                thread->wakeup_ext_cb(thread);
#endif
            break;
        }

        SDL_SemPost(s);
    }

    THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
        thread - threads, THREAD_SDL_GET_NAME(thread));

    new_thread_id(thread->id, thread);
    thread->state = STATE_KILLED;
    thread_queue_wake(&thread->queue);

    SDL_DestroySemaphore(s);

    if (thread == current)
    {
        /* Do a graceful exit - perform the longjmp back into the thread
           function to return */
        restore_irq(oldlevel);
        longjmp(thread_jmpbufs[current - threads], 1);
    }

    SDL_KillThread(t);
    restore_irq(oldlevel);
}

void thread_exit(void)
{
    remove_thread(THREAD_ID_CURRENT);
}

void thread_wait(unsigned int thread_id)
{
    struct thread_entry *current = cores[CURRENT_CORE].running;
    struct thread_entry *thread = thread_id_entry(thread_id);

    if (thread_id == THREAD_ID_CURRENT ||
        (thread->id == thread_id && thread->state != STATE_KILLED))
    {
        current->bqp = &thread->queue;
        block_thread(current);
        switch_thread();
    }
}

int thread_stack_usage(const struct thread_entry *thread)
{
    return 50;
    (void)thread;
}

/* Return name if one or ID if none */
void thread_get_name(char *buffer, int size,
                     struct thread_entry *thread)
{
    if (size <= 0)
        return;

    *buffer = '\0';

    if (thread)
    {
        /* Display thread name if one or ID if none */
        bool named = thread->name && *thread->name;
        const char *fmt = named ? "%s" : "%08lX";
        intptr_t name = named ?
            (intptr_t)thread->name : (intptr_t)thread;
        snprintf(buffer, size, fmt, name);
    }
}