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
 16static time64_t uml_rtc_alarm_time;
 17static bool uml_rtc_alarm_enabled;
 18static struct rtc_device *uml_rtc;
 19static int uml_rtc_irq_fd, uml_rtc_irq;
 20
 21#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
 22
 23static void uml_rtc_time_travel_alarm(struct time_travel_event *ev)
 24{
 25	uml_rtc_send_timetravel_alarm();
 26}
 27
 28static struct time_travel_event uml_rtc_alarm_event = {
 29	.fn = uml_rtc_time_travel_alarm,
 30};
 31#endif
 32
 33static 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
 44static 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
 52static 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
 82static 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
 91static 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
 98static 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
114static 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
137static 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
143static 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;
166cleanup:
167	uml_rtc_cleanup();
168	return err;
169}
170
171static 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
178static 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
186static 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
206unregister:
207	platform_device_put(pdev);
208	platform_driver_unregister(&uml_rtc_driver);
209	return err;
210}
211device_initcall(uml_rtc_init);