arch/um/drivers/rtc_kern.c

   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
  16 static time64_t uml_rtc_alarm_time;
  17 static bool uml_rtc_alarm_enabled;
  18 static struct rtc_device *uml_rtc;
  19 static int uml_rtc_irq_fd, uml_rtc_irq;
  20
  21 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
  22
  23 static void uml_rtc_time_travel_alarm(struct time_travel_event *ev)
  24 {
  25         uml_rtc_send_timetravel_alarm();
  26 }
  27
  28 static struct time_travel_event uml_rtc_alarm_event = {
  29         .fn = uml_rtc_time_travel_alarm,
  30 };
  31 #endif
  32
  33 static 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
  44 static 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
  52 static 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
  82 static 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
  91 static 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
  98 static 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
 114 static 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
 137 static 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
 143 static 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;
 166 cleanup:
 167         uml_rtc_cleanup();
 168         return err;
 169 }
 170
 171 static void uml_rtc_remove(struct platform_device *pdev)
 172 {
 173         device_init_wakeup(&pdev->dev, 0);
 174         uml_rtc_cleanup();
 175 }
 176
 177 static struct platform_driver uml_rtc_driver = {
 178         .probe = uml_rtc_probe,
 179         .remove = uml_rtc_remove,
 180         .driver = {
 181                 .name = "uml-rtc",
 182         },
 183 };
 184
 185 static int __init uml_rtc_init(void)
 186 {
 187         struct platform_device *pdev;
 188         int err;
 189
 190         err = platform_driver_register(&uml_rtc_driver);
 191         if (err)
 192                 return err;
 193
 194         pdev = platform_device_alloc("uml-rtc", 0);
 195         if (!pdev) {
 196                 err = -ENOMEM;
 197                 goto unregister;
 198         }
 199
 200         err = platform_device_add(pdev);
 201         if (err)
 202                 goto unregister;
 203         return 0;
 204
 205 unregister:
 206         platform_device_put(pdev);
 207         platform_driver_unregister(&uml_rtc_driver);
 208         return err;
 209 }
 210 device_initcall(uml_rtc_init);