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 	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 
uml_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)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 
uml_rtc_interrupt(int irq,void * data)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 
uml_rtc_setup(void)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 
uml_rtc_cleanup(void)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 
uml_rtc_probe(struct platform_device * pdev)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 
uml_rtc_remove(struct platform_device * pdev)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 
uml_rtc_init(void)186 static 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 
206 unregister:
207 	platform_device_put(pdev);
208 	platform_driver_unregister(&uml_rtc_driver);
209 	return err;
210 }
211 device_initcall(uml_rtc_init);
212