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(¨_rtc_alarm_event); 73 74 if (enable) 75 time_travel_add_event_rel(¨_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 = ¨_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 int uml_rtc_remove(struct platform_device *pdev) 172 { 173 device_init_wakeup(&pdev->dev, 0); 174 uml_rtc_cleanup(); 175 return 0; 176 } 177 178 static struct platform_driver uml_rtc_driver = { 179 .probe = uml_rtc_probe, 180 .remove = uml_rtc_remove, 181 .driver = { 182 .name = "uml-rtc", 183 }, 184 }; 185 186 static int __init uml_rtc_init(void) 187 { 188 struct platform_device *pdev; 189 int err; 190 191 err = platform_driver_register(¨_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; 205 206 unregister: 207 platform_device_put(pdev); 208 platform_driver_unregister(¨_rtc_driver); 209 return err; 210 } 211 device_initcall(uml_rtc_init); 212