arch/um/drivers/rtc_kern.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2020 Intel Corporation
   4  * Author: Johannes Berg <[email protected]>
   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         struct timespec64 ts;
  55         unsigned long long secs;
  56
  57         if (!enable && !uml_rtc_alarm_enabled)
  58                 return 0;
  59
  60         uml_rtc_alarm_enabled = enable;
  61
  62         read_persistent_clock64(&ts);
  63         secs = uml_rtc_alarm_time - ts.tv_sec;
  64
  65         if (time_travel_mode == TT_MODE_OFF) {
  66                 if (!enable) {
  67                         uml_rtc_disable_alarm();
  68                         return 0;
  69                 }
  70
  71                 /* enable or update */
  72                 return uml_rtc_enable_alarm(secs);
  73         } else {
  74                 time_travel_del_event(&uml_rtc_alarm_event);
  75
  76                 if (enable)
  77                         time_travel_add_event_rel(&uml_rtc_alarm_event,
  78                                                   secs * NSEC_PER_SEC -
  79                                                   ts.tv_nsec);
  80         }
  81
  82         return 0;
  83 }
  84
  85 static int uml_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  86 {
  87         uml_rtc_alarm_irq_enable(dev, 0);
  88         uml_rtc_alarm_time = rtc_tm_to_time64(&alrm->time);
  89         uml_rtc_alarm_irq_enable(dev, alrm->enabled);
  90
  91         return 0;
  92 }
  93
  94 static const struct rtc_class_ops uml_rtc_ops = {
  95         .read_time = uml_rtc_read_time,
  96         .read_alarm = uml_rtc_read_alarm,
  97         .alarm_irq_enable = uml_rtc_alarm_irq_enable,
  98         .set_alarm = uml_rtc_set_alarm,
  99 };
 100
 101 static irqreturn_t uml_rtc_interrupt(int irq, void *data)
 102 {
 103         unsigned long long c = 0;
 104
 105         /* alarm triggered, it's now off */
 106         uml_rtc_alarm_enabled = false;
 107
 108         os_read_file(uml_rtc_irq_fd, &c, sizeof(c));
 109         WARN_ON(c == 0);
 110
 111         pm_system_wakeup();
 112         rtc_update_irq(uml_rtc, 1, RTC_IRQF | RTC_AF);
 113
 114         return IRQ_HANDLED;
 115 }
 116
 117 static int uml_rtc_setup(void)
 118 {
 119         int err;
 120
 121         err = uml_rtc_start(time_travel_mode != TT_MODE_OFF);
 122         if (WARN(err < 0, "err = %d\n", err))
 123                 return err;
 124
 125         uml_rtc_irq_fd = err;
 126
 127         err = um_request_irq(UM_IRQ_ALLOC, uml_rtc_irq_fd, IRQ_READ,
 128                              uml_rtc_interrupt, 0, "rtc", NULL);
 129         if (err < 0) {
 130                 uml_rtc_stop(time_travel_mode != TT_MODE_OFF);
 131                 return err;
 132         }
 133
 134         irq_set_irq_wake(err, 1);
 135
 136         uml_rtc_irq = err;
 137         return 0;
 138 }
 139
 140 static void uml_rtc_cleanup(void)
 141 {
 142         um_free_irq(uml_rtc_irq, NULL);
 143         uml_rtc_stop(time_travel_mode != TT_MODE_OFF);
 144 }
 145
 146 static int uml_rtc_probe(struct platform_device *pdev)
 147 {
 148         int err;
 149
 150         err = uml_rtc_setup();
 151         if (err)
 152                 return err;
 153
 154         uml_rtc = devm_rtc_allocate_device(&pdev->dev);
 155         if (IS_ERR(uml_rtc)) {
 156                 err = PTR_ERR(uml_rtc);
 157                 goto cleanup;
 158         }
 159
 160         uml_rtc->ops = &uml_rtc_ops;
 161
 162         device_init_wakeup(&pdev->dev, 1);
 163
 164         err = devm_rtc_register_device(uml_rtc);
 165         if (err)
 166                 goto cleanup;
 167
 168         return 0;
 169 cleanup:
 170         uml_rtc_cleanup();
 171         return err;
 172 }
 173
 174 static void uml_rtc_remove(struct platform_device *pdev)
 175 {
 176         device_init_wakeup(&pdev->dev, 0);
 177         uml_rtc_cleanup();
 178 }
 179
 180 static struct platform_driver uml_rtc_driver = {
 181         .probe = uml_rtc_probe,
 182         .remove = uml_rtc_remove,
 183         .driver = {
 184                 .name = "uml-rtc",
 185         },
 186 };
 187
 188 static int __init uml_rtc_init(void)
 189 {
 190         struct platform_device *pdev;
 191         int err;
 192
 193         err = platform_driver_register(&uml_rtc_driver);
 194         if (err)
 195                 return err;
 196
 197         pdev = platform_device_alloc("uml-rtc", 0);
 198         if (!pdev) {
 199                 err = -ENOMEM;
 200                 goto unregister;
 201         }
 202
 203         err = platform_device_add(pdev);
 204         if (err)
 205                 goto unregister;
 206         return 0;
 207
 208 unregister:
 209         platform_device_put(pdev);
 210         platform_driver_unregister(&uml_rtc_driver);
 211         return err;
 212 }
 213 device_initcall(uml_rtc_init);