LXR linux/arch/um/drivers/rtc

   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                int 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(uml_rtc_irq_fds[0]);
  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(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