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
uml_rtc_time_travel_alarm(struct time_travel_event * ev)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
uml_rtc_read_time(struct device * dev,struct rtc_time * tm)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
uml_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)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
uml_rtc_alarm_irq_enable(struct device * dev,unsigned int enable)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(¨_rtc_alarm_event);
75
76 if (enable)
77 time_travel_add_event_rel(¨_rtc_alarm_event,
78 secs * NSEC_PER_SEC -
79 ts.tv_nsec);
80 }
81
82 return 0;
83 }
84
uml_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)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
uml_rtc_interrupt(int irq,void * data)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
uml_rtc_setup(void)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
uml_rtc_cleanup(void)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
uml_rtc_probe(struct platform_device * pdev)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 = ¨_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
uml_rtc_remove(struct platform_device * pdev)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
uml_rtc_init(void)188 static int __init uml_rtc_init(void)
189 {
190 struct platform_device *pdev;
191 int err;
192
193 err = platform_driver_register(¨_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(¨_rtc_driver);
211 return err;
212 }
213 device_initcall(uml_rtc_init);
214