xref: /openbmc/linux/arch/um/os-Linux/time.c (revision 842ed298)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
4  * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
5  * Copyright (C) 2012-2014 Cisco Systems
6  * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
7  */
8 
9 #include <stddef.h>
10 #include <unistd.h>
11 #include <errno.h>
12 #include <signal.h>
13 #include <time.h>
14 #include <sys/time.h>
15 #include <kern_util.h>
16 #include <os.h>
17 #include <string.h>
18 
19 static timer_t event_high_res_timer = 0;
20 
21 static inline long long timeval_to_ns(const struct timeval *tv)
22 {
23 	return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
24 		tv->tv_usec * UM_NSEC_PER_USEC;
25 }
26 
27 static inline long long timespec_to_ns(const struct timespec *ts)
28 {
29 	return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) + ts->tv_nsec;
30 }
31 
32 long long os_persistent_clock_emulation(void)
33 {
34 	struct timespec realtime_tp;
35 
36 	clock_gettime(CLOCK_REALTIME, &realtime_tp);
37 	return timespec_to_ns(&realtime_tp);
38 }
39 
40 /**
41  * os_timer_create() - create an new posix (interval) timer
42  */
43 int os_timer_create(void)
44 {
45 	timer_t *t = &event_high_res_timer;
46 
47 	if (timer_create(CLOCK_MONOTONIC, NULL, t) == -1)
48 		return -1;
49 
50 	return 0;
51 }
52 
53 int os_timer_set_interval(unsigned long long nsecs)
54 {
55 	struct itimerspec its;
56 
57 	its.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC;
58 	its.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC;
59 
60 	its.it_interval.tv_sec = nsecs / UM_NSEC_PER_SEC;
61 	its.it_interval.tv_nsec = nsecs % UM_NSEC_PER_SEC;
62 
63 	if (timer_settime(event_high_res_timer, 0, &its, NULL) == -1)
64 		return -errno;
65 
66 	return 0;
67 }
68 
69 int os_timer_one_shot(unsigned long long nsecs)
70 {
71 	struct itimerspec its = {
72 		.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC,
73 		.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC,
74 
75 		.it_interval.tv_sec = 0,
76 		.it_interval.tv_nsec = 0, // we cheat here
77 	};
78 
79 	timer_settime(event_high_res_timer, 0, &its, NULL);
80 	return 0;
81 }
82 
83 /**
84  * os_timer_disable() - disable the posix (interval) timer
85  */
86 void os_timer_disable(void)
87 {
88 	struct itimerspec its;
89 
90 	memset(&its, 0, sizeof(struct itimerspec));
91 	timer_settime(event_high_res_timer, 0, &its, NULL);
92 }
93 
94 long long os_nsecs(void)
95 {
96 	struct timespec ts;
97 
98 	clock_gettime(CLOCK_MONOTONIC,&ts);
99 	return timespec_to_ns(&ts);
100 }
101 
102 /**
103  * os_idle_sleep() - sleep until interrupted
104  */
105 void os_idle_sleep(void)
106 {
107 	struct itimerspec its;
108 	sigset_t set, old;
109 
110 	/* block SIGALRM while we analyze the timer state */
111 	sigemptyset(&set);
112 	sigaddset(&set, SIGALRM);
113 	sigprocmask(SIG_BLOCK, &set, &old);
114 
115 	/* check the timer, and if it'll fire then wait for it */
116 	timer_gettime(event_high_res_timer, &its);
117 	if (its.it_value.tv_sec || its.it_value.tv_nsec)
118 		sigsuspend(&old);
119 	/* either way, restore the signal mask */
120 	sigprocmask(SIG_UNBLOCK, &set, NULL);
121 }
122