xref: /openbmc/linux/arch/um/os-Linux/time.c (revision 95298d63)
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 <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 
18 static timer_t event_high_res_timer = 0;
19 
20 static inline long long timeval_to_ns(const struct timeval *tv)
21 {
22 	return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
23 		tv->tv_usec * UM_NSEC_PER_USEC;
24 }
25 
26 static inline long long timespec_to_ns(const struct timespec *ts)
27 {
28 	return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) + ts->tv_nsec;
29 }
30 
31 long long os_persistent_clock_emulation(void)
32 {
33 	struct timespec realtime_tp;
34 
35 	clock_gettime(CLOCK_REALTIME, &realtime_tp);
36 	return timespec_to_ns(&realtime_tp);
37 }
38 
39 /**
40  * os_timer_create() - create an new posix (interval) timer
41  */
42 int os_timer_create(void)
43 {
44 	timer_t *t = &event_high_res_timer;
45 
46 	if (timer_create(CLOCK_MONOTONIC, NULL, t) == -1)
47 		return -1;
48 
49 	return 0;
50 }
51 
52 int os_timer_set_interval(unsigned long long nsecs)
53 {
54 	struct itimerspec its;
55 
56 	its.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC;
57 	its.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC;
58 
59 	its.it_interval.tv_sec = nsecs / UM_NSEC_PER_SEC;
60 	its.it_interval.tv_nsec = nsecs % UM_NSEC_PER_SEC;
61 
62 	if (timer_settime(event_high_res_timer, 0, &its, NULL) == -1)
63 		return -errno;
64 
65 	return 0;
66 }
67 
68 int os_timer_one_shot(unsigned long long nsecs)
69 {
70 	struct itimerspec its = {
71 		.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC,
72 		.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC,
73 
74 		.it_interval.tv_sec = 0,
75 		.it_interval.tv_nsec = 0, // we cheat here
76 	};
77 
78 	timer_settime(event_high_res_timer, 0, &its, NULL);
79 	return 0;
80 }
81 
82 /**
83  * os_timer_disable() - disable the posix (interval) timer
84  */
85 void os_timer_disable(void)
86 {
87 	struct itimerspec its;
88 
89 	memset(&its, 0, sizeof(struct itimerspec));
90 	timer_settime(event_high_res_timer, 0, &its, NULL);
91 }
92 
93 long long os_nsecs(void)
94 {
95 	struct timespec ts;
96 
97 	clock_gettime(CLOCK_MONOTONIC,&ts);
98 	return timespec_to_ns(&ts);
99 }
100 
101 /**
102  * os_idle_sleep() - sleep for a given time of nsecs
103  * @nsecs: nanoseconds to sleep
104  */
105 void os_idle_sleep(unsigned long long nsecs)
106 {
107 	struct timespec ts = {
108 		.tv_sec  = nsecs / UM_NSEC_PER_SEC,
109 		.tv_nsec = nsecs % UM_NSEC_PER_SEC
110 	};
111 
112 	/*
113 	 * Relay the signal if clock_nanosleep is interrupted.
114 	 */
115 	if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL))
116 		deliver_alarm();
117 }
118