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
|
/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Task scheduling / events module for Chrome EC operating system */
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include "atomic.h"
#include "common.h"
#include "task.h"
#include "task_id.h"
#include "test_util.h"
#include "timer.h"
struct emu_task_t {
pthread_t thread;
pthread_cond_t resume;
uint32_t event;
timestamp_t wake_time;
uint8_t started;
};
struct task_args {
void (*routine)(void *);
void *d;
};
static struct emu_task_t tasks[TASK_ID_COUNT];
static pthread_cond_t scheduler_cond;
static pthread_mutex_t run_lock;
static task_id_t running_task_id;
static sem_t interrupt_sem;
static pthread_mutex_t interrupt_lock;
static pthread_t interrupt_thread;
static int in_interrupt;
static int interrupt_disabled;
static void (*pending_isr)(void);
static int generator_sleeping;
static timestamp_t generator_sleep_deadline;
static int has_interrupt_generator = 1;
static __thread task_id_t my_task_id; /* thread local task id */
#define TASK(n, r, d, s) void r(void *);
CONFIG_TASK_LIST
CONFIG_TEST_TASK_LIST
#undef TASK
/* Idle task */
void __idle(void *d)
{
while (1)
task_wait_event(-1);
}
void _run_test(void *d)
{
run_test();
}
#define TASK(n, r, d, s) {r, d},
struct task_args task_info[TASK_ID_COUNT] = {
{__idle, NULL},
CONFIG_TASK_LIST
CONFIG_TEST_TASK_LIST
{_run_test, NULL},
};
#undef TASK
#define TASK(n, r, d, s) #n,
static const char * const task_names[] = {
"<< idle >>",
CONFIG_TASK_LIST
CONFIG_TEST_TASK_LIST
"<< test runner >>",
};
#undef TASK
void task_pre_init(void)
{
/* Nothing */
}
int in_interrupt_context(void)
{
return !!in_interrupt;
}
void interrupt_disable(void)
{
interrupt_disabled = 1;
}
void interrupt_enable(void)
{
interrupt_disabled = 0;
}
void _task_execute_isr(int sig)
{
in_interrupt = 1;
pending_isr();
sem_post(&interrupt_sem);
in_interrupt = 0;
}
void task_register_interrupt(void)
{
sem_init(&interrupt_sem, 0, 0);
signal(SIGUSR1, _task_execute_isr);
}
void task_trigger_test_interrupt(void (*isr)(void))
{
if (interrupt_disabled)
return;
pthread_mutex_lock(&interrupt_lock);
/* Suspend current task and excute ISR */
pending_isr = isr;
pthread_kill(tasks[running_task_id].thread, SIGUSR1);
/* Wait for ISR to complete */
sem_wait(&interrupt_sem);
while (in_interrupt)
;
pending_isr = NULL;
pthread_mutex_unlock(&interrupt_lock);
}
void interrupt_generator_udelay(unsigned us)
{
generator_sleep_deadline.val = get_time().val + us;
generator_sleeping = 1;
while (get_time().val < generator_sleep_deadline.val)
;
generator_sleeping = 0;
}
uint32_t task_set_event(task_id_t tskid, uint32_t event, int wait)
{
tasks[tskid].event = event;
if (wait)
return task_wait_event(-1);
return 0;
}
uint32_t task_wait_event(int timeout_us)
{
int tid = task_get_current();
int ret;
pthread_mutex_lock(&interrupt_lock);
if (timeout_us > 0)
tasks[tid].wake_time.val = get_time().val + timeout_us;
/* Transfer control to scheduler */
pthread_cond_signal(&scheduler_cond);
pthread_cond_wait(&tasks[tid].resume, &run_lock);
/* Resume */
ret = tasks[tid].event;
tasks[tid].event = 0;
pthread_mutex_unlock(&interrupt_lock);
return ret;
}
void mutex_lock(struct mutex *mtx)
{
int value = 0;
int id = 1 << task_get_current();
mtx->waiters |= id;
do {
if (mtx->lock == 0) {
mtx->lock = 1;
value = 1;
}
if (!value)
task_wait_event(-1);
} while (!value);
mtx->waiters &= ~id;
}
void mutex_unlock(struct mutex *mtx)
{
int v;
mtx->lock = 0;
for (v = 31; v >= 0; --v)
if ((1ul << v) & mtx->waiters) {
mtx->waiters &= ~(1ul << v);
task_set_event(v, TASK_EVENT_MUTEX, 0);
break;
}
}
task_id_t task_get_current(void)
{
return my_task_id;
}
void wait_for_task_started(void)
{
int i, ok;
while (1) {
ok = 1;
for (i = 0; i < TASK_ID_COUNT - 1; ++i)
if (!tasks[i].started) {
msleep(10);
ok = 0;
break;
}
if (ok)
return;
}
}
static task_id_t task_get_next_wake(void)
{
int i;
timestamp_t min_time;
int which_task = TASK_ID_INVALID;
min_time.val = ~0ull;
for (i = TASK_ID_COUNT - 1; i >= 0; --i)
if (min_time.val >= tasks[i].wake_time.val) {
min_time.val = tasks[i].wake_time.val;
which_task = i;
}
return which_task;
}
static int fast_forward(void)
{
/*
* No task has event pending, and thus the next time we have an
* event to process must be either of:
* 1. Interrupt generator triggers an interrupt
* 2. The next wake alarm is reached
* So we should check whether an interrupt may happen, and fast
* forward to the nearest among:
* 1. When interrupt generator wakes up
* 2. When the next task wakes up
*/
int task_id = task_get_next_wake();
if (!has_interrupt_generator) {
if (task_id == TASK_ID_INVALID) {
return TASK_ID_IDLE;
} else {
force_time(tasks[task_id].wake_time);
return task_id;
}
}
if (!generator_sleeping)
return TASK_ID_IDLE;
if (task_id != TASK_ID_INVALID &&
tasks[task_id].wake_time.val < generator_sleep_deadline.val) {
force_time(tasks[task_id].wake_time);
return task_id;
} else {
force_time(generator_sleep_deadline);
return TASK_ID_IDLE;
}
}
void task_scheduler(void)
{
int i;
timestamp_t now;
while (1) {
now = get_time();
i = TASK_ID_COUNT - 1;
while (i >= 0) {
if (tasks[i].event || now.val >= tasks[i].wake_time.val)
break;
--i;
}
if (i < 0)
i = fast_forward();
tasks[i].wake_time.val = ~0ull;
running_task_id = i;
tasks[i].started = 1;
pthread_cond_signal(&tasks[i].resume);
pthread_cond_wait(&scheduler_cond, &run_lock);
}
}
void *_task_start_impl(void *a)
{
long tid = (long)a;
struct task_args *arg = task_info + tid;
my_task_id = tid;
pthread_mutex_lock(&run_lock);
/* Wait for scheduler */
task_wait_event(1);
tasks[tid].event = 0;
/* Start the task routine */
(arg->routine)(arg->d);
/* Catch exited routine */
while (1)
task_wait_event(-1);
}
test_mockable void interrupt_generator(void)
{
has_interrupt_generator = 0;
}
void *_task_int_generator_start(void *d)
{
my_task_id = TASK_ID_INT_GEN;
interrupt_generator();
return NULL;
}
int task_start(void)
{
int i;
task_register_interrupt();
pthread_mutex_init(&run_lock, NULL);
pthread_mutex_init(&interrupt_lock, NULL);
pthread_cond_init(&scheduler_cond, NULL);
pthread_mutex_lock(&run_lock);
for (i = 0; i < TASK_ID_COUNT; ++i) {
tasks[i].event = TASK_EVENT_WAKE;
tasks[i].wake_time.val = ~0ull;
tasks[i].started = 0;
pthread_cond_init(&tasks[i].resume, NULL);
pthread_create(&tasks[i].thread, NULL, _task_start_impl,
(void *)(uintptr_t)i);
pthread_cond_wait(&scheduler_cond, &run_lock);
/*
* Interrupt lock is grabbed by the task which just started.
* Let's unlock it so the next task can be started.
*/
pthread_mutex_unlock(&interrupt_lock);
}
/*
* All tasks are now waiting in task_wait_event(). Lock interrupt_lock
* here so the first task chosen sees it locked.
*/
pthread_mutex_lock(&interrupt_lock);
pthread_create(&interrupt_thread, NULL,
_task_int_generator_start, NULL);
task_scheduler();
return 0;
}
|