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 <linux/platform_device.h>
   7#include <linux/time-internal.h>
   8#include <linux/suspend.h>
   9#include <linux/err.h>
  10#include <linux/rtc.h>
  11#include <kern_util.h>
  12#include <irq_kern.h>
  13#include <os.h>
  14#include "rtc.h"
  15
  16static time64_t uml_rtc_alarm_time;
  17static bool uml_rtc_alarm_enabled;
  18static struct rtc_device *uml_rtc;
  19static int uml_rtc_irq_fd, uml_rtc_irq;
  20
  21#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
  22
  23static void uml_rtc_time_travel_alarm(struct time_travel_event *ev)
  24{
  25        uml_rtc_send_timetravel_alarm();
  26}
  27
  28static struct time_travel_event uml_rtc_alarm_event = {
  29        .fn = uml_rtc_time_travel_alarm,
  30};
  31#endif
  32
  33static int uml_rtc_read_time(struct device *dev, struct rtc_time *tm)
  34{
  35        struct timespec64 ts;
  36
  37        /* Use this to get correct time in time-travel mode */
  38        read_persistent_clock64(&ts);
  39        rtc_time64_to_tm(timespec64_to_ktime(ts) / NSEC_PER_SEC, tm);
  40
  41        return 0;
  42}
  43
  44static int uml_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  45{
  46        rtc_time64_to_tm(uml_rtc_alarm_time, &alrm->time);
  47        alrm->enabled = uml_rtc_alarm_enabled;
  48
  49        return 0;
  50}
  51
  52static int uml_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
  53{
  54        unsigned long long secs;
  55
  56        if (!enable && !uml_rtc_alarm_enabled)
  57                return 0;
  58
  59        uml_rtc_alarm_enabled = enable;
  60
  61        secs = uml_rtc_alarm_time - ktime_get_real_seconds();
  62
  63        if (time_travel_mode == TT_MODE_OFF) {
  64                if (!enable) {
  65                        uml_rtc_disable_alarm();
  66                        return 0;
  67                }
  68
  69                /* enable or update */
  70                return uml_rtc_enable_alarm(secs);
  71        } else {
  72                time_travel_del_event(&uml_rtc_alarm_event);
  73
  74                if (enable)
  75                        time_travel_add_event_rel(&uml_rtc_alarm_event,
  76                                                  secs * NSEC_PER_SEC);
  77        }
  78
  79        return 0;
  80}
  81
  82static int uml_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  83{
  84        uml_rtc_alarm_irq_enable(dev, 0);
  85        uml_rtc_alarm_time = rtc_tm_to_time64(&alrm->time);
  86        uml_rtc_alarm_irq_enable(dev, alrm->enabled);
  87
  88        return 0;
  89}
  90
  91static const struct rtc_class_ops uml_rtc_ops = {
  92        .read_time = uml_rtc_read_time,
  93        .read_alarm = uml_rtc_read_alarm,
  94        .alarm_irq_enable = uml_rtc_alarm_irq_enable,
  95        .set_alarm = uml_rtc_set_alarm,
  96};
  97
  98static irqreturn_t uml_rtc_interrupt(int irq, void *data)
  99{
 100        unsigned long long c = 0;
 101
 102        /* alarm triggered, it's now off */
 103        uml_rtc_alarm_enabled = false;
 104
 105        os_read_file(uml_rtc_irq_fd, &c, sizeof(c));
 106        WARN_ON(c == 0);
 107
 108        pm_system_wakeup();
 109        rtc_update_irq(uml_rtc, 1, RTC_IRQF | RTC_AF);
 110
 111        return IRQ_HANDLED;
 112}
 113
 114static int uml_rtc_setup(void)
 115{
 116        int err;
 117
 118        err = uml_rtc_start(time_travel_mode != TT_MODE_OFF);
 119        if (WARN(err < 0, "err = %d\n", err))
 120                return err;
 121
 122        uml_rtc_irq_fd = err;
 123
 124        err = um_request_irq(UM_IRQ_ALLOC, uml_rtc_irq_fd, IRQ_READ,
 125                             uml_rtc_interrupt, 0, "rtc", NULL);
 126        if (err < 0) {
 127                uml_rtc_stop(time_travel_mode != TT_MODE_OFF);
 128                return err;
 129        }
 130
 131        irq_set_irq_wake(err, 1);
 132
 133        uml_rtc_irq = err;
 134        return 0;
 135}
 136
 137static void uml_rtc_cleanup(void)
 138{
 139        um_free_irq(uml_rtc_irq, NULL);
 140        uml_rtc_stop(time_travel_mode != TT_MODE_OFF);
 141}
 142
 143static int uml_rtc_probe(struct platform_device *pdev)
 144{
 145        int err;
 146
 147        err = uml_rtc_setup();
 148        if (err)
 149                return err;
 150
 151        uml_rtc = devm_rtc_allocate_device(&pdev->dev);
 152        if (IS_ERR(uml_rtc)) {
 153                err = PTR_ERR(uml_rtc);
 154                goto cleanup;
 155        }
 156
 157        uml_rtc->ops = &uml_rtc_ops;
 158
 159        device_init_wakeup(&pdev->dev, 1);
 160
 161        err = devm_rtc_register_device(uml_rtc);
 162        if (err)
 163                goto cleanup;
 164
 165        return 0;
 166cleanup:
 167        uml_rtc_cleanup();
 168        return err;
 169}
 170
 171static int uml_rtc_remove(struct platform_device *pdev)
 172{
 173        device_init_wakeup(&pdev->dev, 0);
 174        uml_rtc_cleanup();
 175        return 0;
 176}
 177
 178static struct platform_driver uml_rtc_driver = {
 179        .probe = uml_rtc_probe,
 180        .remove = uml_rtc_remove,
 181        .driver = {
 182                .name = "uml-rtc",
 183        },
 184};
 185
 186static int __init uml_rtc_init(void)
 187{
 188        struct platform_device *pdev;
 189        int err;
 190
 191        err = platform_driver_register(&uml_rtc_driver);
 192        if (err)
 193                return err;
 194
 195        pdev = platform_device_alloc("uml-rtc", 0);
 196        if (!pdev) {
 197                err = -ENOMEM;
 198                goto unregister;
 199        }
 200
 201        err = platform_device_add(pdev);
 202        if (err)
 203                goto unregister;
 204        return 0;
 205
 206unregister:
 207        platform_device_put(pdev);
 208        platform_driver_unregister(&uml_rtc_driver);
 209        return err;
 210}
 211device_initcall(uml_rtc_init);
 212