1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020 Intel Corporation
4 * Author: Johannes Berg <johannes@sipsolutions.net>
5 */
6#include <stdbool.h>
7#include <os.h>
8#include <errno.h>
9#include <sched.h>
10#include <unistd.h>
11#include <kern_util.h>
12#include <sys/select.h>
13#include <stdio.h>
14#include <sys/timerfd.h>
15#include "rtc.h"
16
17static int uml_rtc_irq_fds[2];
18
19void uml_rtc_send_timetravel_alarm(void)
20{
21 unsigned long long c = 1;
22
23 CATCH_EINTR(write(uml_rtc_irq_fds[1], &c, sizeof(c)));
24}
25
26int uml_rtc_start(bool timetravel)
27{
28 int err;
29
30 if (timetravel) {
31 err = os_pipe(uml_rtc_irq_fds, 1, 1);
32 if (err)
33 goto fail;
34 } else {
35 uml_rtc_irq_fds[0] = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
36 if (uml_rtc_irq_fds[0] < 0) {
37 err = -errno;
38 goto fail;
39 }
40
41 /* apparently timerfd won't send SIGIO, use workaround */
42 sigio_broken();
43 err = add_sigio_fd(uml_rtc_irq_fds[0]);
44 if (err < 0) {
45 close(uml_rtc_irq_fds[0]);
46 goto fail;
47 }
48 }
49
50 return uml_rtc_irq_fds[0];
51fail:
52 uml_rtc_stop(timetravel);
53 return err;
54}
55
56int uml_rtc_enable_alarm(unsigned long long delta_seconds)
57{
58 struct itimerspec it = {
59 .it_value = {
60 .tv_sec = delta_seconds,
61 },
62 };
63
64 if (timerfd_settime(uml_rtc_irq_fds[0], 0, &it, NULL))
65 return -errno;
66 return 0;
67}
68
69void uml_rtc_disable_alarm(void)
70{
71 uml_rtc_enable_alarm(delta_seconds: 0);
72}
73
74void uml_rtc_stop(bool timetravel)
75{
76 if (timetravel)
77 os_close_file(uml_rtc_irq_fds[1]);
78 else
79 ignore_sigio_fd(uml_rtc_irq_fds[0]);
80 os_close_file(uml_rtc_irq_fds[0]);
81}
82

source code of linux/arch/um/drivers/rtc_user.c