xref: /openbmc/linux/arch/um/os-Linux/time.c (revision f3539c12)
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) +
30 		ts->tv_nsec;
31 }
32 
33 long long os_persistent_clock_emulation (void) {
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* timer) {
44 
45 	timer_t* t = timer;
46 
47 	if(t == NULL) {
48 		t = &event_high_res_timer;
49 	}
50 
51 	if (timer_create(
52 		CLOCK_MONOTONIC,
53 		NULL,
54 		t) == -1) {
55 		return -1;
56 	}
57 	return 0;
58 }
59 
60 int os_timer_set_interval(void* timer, void* i)
61 {
62 	struct itimerspec its;
63 	unsigned long long nsec;
64 	timer_t* t = timer;
65 	struct itimerspec* its_in = i;
66 
67 	if(t == NULL) {
68 		t = &event_high_res_timer;
69 	}
70 
71 	nsec = UM_NSEC_PER_SEC / UM_HZ;
72 
73 	if(its_in != NULL) {
74 		its.it_value.tv_sec = its_in->it_value.tv_sec;
75 		its.it_value.tv_nsec = its_in->it_value.tv_nsec;
76 	} else {
77 		its.it_value.tv_sec = 0;
78 		its.it_value.tv_nsec = nsec;
79 	}
80 
81 	its.it_interval.tv_sec = 0;
82 	its.it_interval.tv_nsec = nsec;
83 
84 	if(timer_settime(*t, 0, &its, NULL) == -1) {
85 		return -errno;
86 	}
87 
88 	return 0;
89 }
90 
91 /**
92  * os_timer_remain() - returns the remaining nano seconds of the given interval
93  *                     timer
94  * Because this is the remaining time of an interval timer, which correspondends
95  * to HZ, this value can never be bigger than one second. Just
96  * the nanosecond part of the timer is returned.
97  * The returned time is relative to the start time of the interval timer.
98  * Return an negative value in an error case.
99  */
100 long os_timer_remain(void* timer)
101 {
102 	struct itimerspec its;
103 	timer_t* t = timer;
104 
105 	if(t == NULL) {
106 		t = &event_high_res_timer;
107 	}
108 
109 	if(timer_gettime(t, &its) == -1) {
110 		return -errno;
111 	}
112 
113 	return its.it_value.tv_nsec;
114 }
115 
116 int os_timer_one_shot(int ticks)
117 {
118 	struct itimerspec its;
119 	unsigned long long nsec;
120 	unsigned long sec;
121 
122     nsec = (ticks + 1);
123     sec = nsec / UM_NSEC_PER_SEC;
124 	nsec = nsec % UM_NSEC_PER_SEC;
125 
126 	its.it_value.tv_sec = nsec / UM_NSEC_PER_SEC;
127 	its.it_value.tv_nsec = nsec;
128 
129 	its.it_interval.tv_sec = 0;
130 	its.it_interval.tv_nsec = 0; // we cheat here
131 
132 	timer_settime(event_high_res_timer, 0, &its, NULL);
133 	return 0;
134 }
135 
136 /**
137  * os_timer_disable() - disable the posix (interval) timer
138  * Returns the remaining interval timer time in nanoseconds
139  */
140 long long os_timer_disable(void)
141 {
142 	struct itimerspec its;
143 
144 	memset(&its, 0, sizeof(struct itimerspec));
145 	timer_settime(event_high_res_timer, 0, &its, &its);
146 
147 	return its.it_value.tv_sec * UM_NSEC_PER_SEC + its.it_value.tv_nsec;
148 }
149 
150 long long os_vnsecs(void)
151 {
152 	struct timespec ts;
153 
154 	clock_gettime(CLOCK_PROCESS_CPUTIME_ID,&ts);
155 	return timespec_to_ns(&ts);
156 }
157 
158 long long os_nsecs(void)
159 {
160 	struct timespec ts;
161 
162 	clock_gettime(CLOCK_MONOTONIC,&ts);
163 	return timespec_to_ns(&ts);
164 }
165 
166 /**
167  * os_idle_sleep() - sleep for a given time of nsecs
168  * @nsecs: nanoseconds to sleep
169  */
170 void os_idle_sleep(unsigned long long nsecs)
171 {
172 	struct timespec ts;
173 
174 	if (nsecs <= 0) {
175 		return;
176 	}
177 
178 	ts = ((struct timespec) {
179 			.tv_sec  = nsecs / UM_NSEC_PER_SEC,
180 			.tv_nsec = nsecs % UM_NSEC_PER_SEC
181 	});
182 
183 	/*
184 	 * Relay the signal if clock_nanosleep is interrupted.
185 	 */
186 	if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL)) {
187 		deliver_alarm();
188 	}
189 }
190