1 /*
2 * This file is part of the flashrom project.
3 *
4 * Copyright (C) 2000 Silicon Integrated System Corporation
5 * Copyright (C) 2009,2010 Carl-Daniel Hailfinger
6 * Copyright (C) 2024 Google LLC
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19 #ifndef __LIBPAYLOAD__
20
21 #include <stdbool.h>
22 #include <unistd.h>
23 #include <errno.h>
24 #include <time.h>
25 #include <sys/time.h>
26 #include <stdlib.h>
27 #include <limits.h>
28 #include "flash.h"
29 #include "programmer.h"
30
31 #if HAVE_CLOCK_GETTIME == 1
32
clock_usec_delay(int usecs)33 static void clock_usec_delay(int usecs)
34 {
35 static clockid_t clock_id =
36 #ifdef _POSIX_MONOTONIC_CLOCK
37 CLOCK_MONOTONIC;
38 #else
39 CLOCK_REALTIME;
40 #endif
41
42 struct timespec now;
43 if (clock_gettime(clock_id, &now)) {
44 /* Fall back to realtime clock if monotonic doesn't work */
45 if (clock_id != CLOCK_REALTIME && errno == EINVAL) {
46 clock_id = CLOCK_REALTIME;
47 clock_gettime(clock_id, &now);
48 }
49 }
50
51 const long end_nsec = now.tv_nsec + usecs * 1000L;
52 const struct timespec end = {
53 end_nsec / (1000 * 1000 * 1000) + now.tv_sec,
54 end_nsec % (1000 * 1000 * 1000)
55 };
56 do {
57 clock_gettime(clock_id, &now);
58 } while (now.tv_sec < end.tv_sec || (now.tv_sec == end.tv_sec && now.tv_nsec < end.tv_nsec));
59 }
60
61 #else
62
clock_usec_delay(unsigned int usecs)63 static void clock_usec_delay(unsigned int usecs) {
64 struct timeval start, end;
65 unsigned long elapsed = 0;
66
67 gettimeofday(&start, NULL);
68
69 while (elapsed < usecs) {
70 gettimeofday(&end, NULL);
71 elapsed = 1000000 * (end.tv_sec - start.tv_sec) +
72 (end.tv_usec - start.tv_usec);
73 /* Protect against time going forward too much. */
74 if ((end.tv_sec > start.tv_sec) &&
75 ((end.tv_sec - start.tv_sec) >= LONG_MAX / 1000000 - 1))
76 elapsed = 0;
77 /* Protect against time going backwards during leap seconds. */
78 if ((end.tv_sec < start.tv_sec) || (elapsed > LONG_MAX))
79 elapsed = 0;
80 }
81 }
82
83 #endif /* HAVE_CLOCK_GETTIME == 1 */
84
85 /* Not very precise sleep. */
internal_sleep(unsigned int usecs)86 void internal_sleep(unsigned int usecs)
87 {
88 #if IS_WINDOWS
89 Sleep((usecs + 999) / 1000);
90 #else
91 nanosleep(&(struct timespec){usecs / 1000000, (usecs * 1000) % 1000000000UL}, NULL);
92 #endif
93 }
94
95 static const unsigned min_sleep = CONFIG_DELAY_MINIMUM_SLEEP_US;
96
97 /* Precise delay. */
default_delay(unsigned int usecs)98 void default_delay(unsigned int usecs)
99 {
100 if (usecs < min_sleep) {
101 clock_usec_delay(usecs);
102 } else {
103 internal_sleep(usecs);
104 }
105 }
106
107 #else
108 #include <libpayload.h>
109
default_delay(unsigned int usecs)110 void default_delay(unsigned int usecs)
111 {
112 udelay(usecs);
113 }
114 #endif
115