xref: /openbmc/linux/arch/um/os-Linux/time.c (revision 1edd0337)
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 timespec_to_ns(const struct timespec *ts)
22 {
23 	return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) + ts->tv_nsec;
24 }
25 
26 long long os_persistent_clock_emulation(void)
27 {
28 	struct timespec realtime_tp;
29 
30 	clock_gettime(CLOCK_REALTIME, &realtime_tp);
31 	return timespec_to_ns(&realtime_tp);
32 }
33 
34 /**
35  * os_timer_create() - create an new posix (interval) timer
36  */
37 int os_timer_create(void)
38 {
39 	timer_t *t = &event_high_res_timer;
40 
41 	if (timer_create(CLOCK_MONOTONIC, NULL, t) == -1)
42 		return -1;
43 
44 	return 0;
45 }
46 
47 int os_timer_set_interval(unsigned long long nsecs)
48 {
49 	struct itimerspec its;
50 
51 	its.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC;
52 	its.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC;
53 
54 	its.it_interval.tv_sec = nsecs / UM_NSEC_PER_SEC;
55 	its.it_interval.tv_nsec = nsecs % UM_NSEC_PER_SEC;
56 
57 	if (timer_settime(event_high_res_timer, 0, &its, NULL) == -1)
58 		return -errno;
59 
60 	return 0;
61 }
62 
63 int os_timer_one_shot(unsigned long long nsecs)
64 {
65 	struct itimerspec its = {
66 		.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC,
67 		.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC,
68 
69 		.it_interval.tv_sec = 0,
70 		.it_interval.tv_nsec = 0, // we cheat here
71 	};
72 
73 	timer_settime(event_high_res_timer, 0, &its, NULL);
74 	return 0;
75 }
76 
77 /**
78  * os_timer_disable() - disable the posix (interval) timer
79  */
80 void os_timer_disable(void)
81 {
82 	struct itimerspec its;
83 
84 	memset(&its, 0, sizeof(struct itimerspec));
85 	timer_settime(event_high_res_timer, 0, &its, NULL);
86 }
87 
88 long long os_nsecs(void)
89 {
90 	struct timespec ts;
91 
92 	clock_gettime(CLOCK_MONOTONIC,&ts);
93 	return timespec_to_ns(&ts);
94 }
95 
96 /**
97  * os_idle_sleep() - sleep until interrupted
98  */
99 void os_idle_sleep(void)
100 {
101 	struct itimerspec its;
102 	sigset_t set, old;
103 
104 	/* block SIGALRM while we analyze the timer state */
105 	sigemptyset(&set);
106 	sigaddset(&set, SIGALRM);
107 	sigprocmask(SIG_BLOCK, &set, &old);
108 
109 	/* check the timer, and if it'll fire then wait for it */
110 	timer_gettime(event_high_res_timer, &its);
111 	if (its.it_value.tv_sec || its.it_value.tv_nsec)
112 		sigsuspend(&old);
113 	/* either way, restore the signal mask */
114 	sigprocmask(SIG_UNBLOCK, &set, NULL);
115 }
116