xref: /openbmc/linux/arch/um/os-Linux/time.c (revision 2169e6da)
1 /*
2  * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
3  * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
4  * Copyright (C) 2012-2014 Cisco Systems
5  * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
6  * Licensed under the GPL
7  */
8 
9 #include <stddef.h>
10 #include <errno.h>
11 #include <signal.h>
12 #include <time.h>
13 #include <sys/time.h>
14 #include <kern_util.h>
15 #include <os.h>
16 #include <string.h>
17 #include <timer-internal.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 for a given time of nsecs
104  * @nsecs: nanoseconds to sleep
105  */
106 void os_idle_sleep(unsigned long long nsecs)
107 {
108 	struct timespec ts = {
109 		.tv_sec  = nsecs / UM_NSEC_PER_SEC,
110 		.tv_nsec = nsecs % UM_NSEC_PER_SEC
111 	};
112 
113 	/*
114 	 * Relay the signal if clock_nanosleep is interrupted.
115 	 */
116 	if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL))
117 		deliver_alarm();
118 }
119