summaryrefslogtreecommitdiffstats
path: root/firmware/kernel/pthread/thread.c
blob: a80ce876e8ba255bb684adcf6ac25a54e606c184 (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
#include <stdlib.h>
#include <stdbool.h>
#include <errno.h>
#include <pthread.h>
#include "/usr/include/semaphore.h"
#include "kernel.h"
#include "thread.h"

#define NSEC_PER_SEC 1000000000L
static inline void timespec_add_ns(struct timespec *a, uint64_t ns)
{
    lldiv_t q = lldiv(a->tv_nsec + ns, NSEC_PER_SEC);
    a->tv_sec += q.quot;
    a->tv_nsec = q.rem;
}

static int threads_initialized;

struct thread_init_data {
    void (*function)(void);
    bool start_frozen;
    sem_t init_sem;
    struct thread_entry *entry;
};

__thread struct thread_entry *_current;

struct thread_entry* thread_self_entry(void)
{
    return _current;
}

unsigned int thread_self(void)
{
    return (unsigned) pthread_self();
}

static struct thread_entry_item {
    unsigned thread_id;
    struct thread_entry *entry;
} entry_lookup[32];



static struct thread_entry_item *__find_thread_entry(unsigned thread_id)
{
    int i;
    
    for (i = 0; i < 32; i++)
    {
        if (entry_lookup[i].thread_id == thread_id)
            return &entry_lookup[i];
    }
    return NULL;
}

static struct thread_entry *find_thread_entry(unsigned thread_id)
{
    return __find_thread_entry(thread_id)->entry;
}

static void *trampoline(void *arg)
{
    struct thread_init_data *data = arg;

    void (*thread_fn)(void) = data->function;

    _current = data->entry;

    if (data->start_frozen)
    {
        struct corelock thaw_lock;
        struct thread_entry *queue = NULL;
        corelock_init(&thaw_lock);
        corelock_lock(&thaw_lock);

        _current->lock = &thaw_lock;
        _current->bqp = &queue;
        sem_post(&data->init_sem);
        block_thread_switch(_current, _current->lock);
        _current->lock = NULL;

        corelock_unlock(&thaw_lock);
    }
    else
        sem_post(&data->init_sem);

    free(data);
    thread_fn();

    return NULL;
}

void thread_thaw(unsigned int thread_id)
{
    struct thread_entry *e = find_thread_entry(thread_id);
    if (e->lock)
    {
        corelock_lock(e->lock);
        wakeup_thread(e->bqp);
        corelock_unlock(e->lock);
    }
    /* else: no lock. must be running already */
}

void init_threads(void)
{
    struct thread_entry_item *item0 = &entry_lookup[0];
    item0->entry = calloc(1, sizeof(struct thread_entry));
    item0->thread_id = pthread_self();

    _current = item0->entry;
    pthread_cond_init(&item0->entry->cond, NULL);
    threads_initialized = 1;
}


unsigned int create_thread(void (*function)(void),
                           void* stack, size_t stack_size,
                           unsigned flags, const char *name
                           //~ IF_PRIO(, int priority)
                           IF_COP(, unsigned int core))
{
    pthread_t retval;

    struct thread_init_data *data = calloc(1, sizeof(struct thread_init_data));
    struct thread_entry *entry = calloc(1, sizeof(struct thread_entry));
    struct thread_entry_item *item;

    if (!threads_initialized)
        abort();

    data->function = function;
    data->start_frozen = flags & CREATE_THREAD_FROZEN;
    data->entry = entry;
    pthread_cond_init(&entry->cond, NULL);         
    entry->runnable = true;
    entry->l = (struct thread_list) { NULL, NULL };
    sem_init(&data->init_sem, 0, 0);

    if (pthread_create(&retval, NULL, trampoline, data) < 0)
        return -1;

    sem_wait(&data->init_sem);

    item = __find_thread_entry(0);
    item->thread_id = retval;
    item->entry = entry;

    pthread_setname_np(retval, name);
    

    return retval;
}

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_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;
}

/* for block_thread(), _w_tmp() and wakeup_thread() t->lock must point
 * to a corelock instance, and this corelock must be held by the caller */
void block_thread_switch(struct thread_entry *t, struct corelock *cl)
{
    t->runnable = false;
    add_to_list_l(t->bqp, t);
    while(!t->runnable)
        pthread_cond_wait(&t->cond, &cl->mutex);
}

void block_thread_switch_w_tmo(struct thread_entry *t, int timeout, struct corelock *cl)
{
    int err = 0;
    struct timespec ts;

    clock_gettime(CLOCK_REALTIME, &ts);
    timespec_add_ns(&ts, timeout * (NSEC_PER_SEC/HZ));

    t->runnable = false;
    add_to_list_l(t->bqp, t);
    while(!t->runnable && !err)
        err = pthread_cond_timedwait(&t->cond, &cl->mutex, &ts);

    if (err == ETIMEDOUT)
    {   /* the thread timed out and was not explicitely woken up.
         * we need to do this now to mark it runnable again */
        remove_from_list_l(t->bqp, t);
        t->runnable = true;
        if (t->wakeup_ext_cb)
            t->wakeup_ext_cb(t);
    }
}

unsigned int wakeup_thread(struct thread_entry **list)
{
    struct thread_entry *t = *list;
    if (t)
    {
        remove_from_list_l(list, t);
        t->runnable = true;
        pthread_cond_signal(&t->cond);
    }
    return THREAD_NONE;
}


void yield(void) {}

unsigned sleep(unsigned ticks)
{
    struct timespec ts;

    ts.tv_sec = ticks/HZ;
    ts.tv_nsec = (ticks % HZ) * (NSEC_PER_SEC/HZ);

    nanosleep(&ts, NULL);

    return 0;
}