1// SPDX-License-Identifier: GPL-2.0
2/* drivers/rtc/rtc-goldfish.c
3 *
4 * Copyright (C) 2007 Google, Inc.
5 * Copyright (C) 2017 Imagination Technologies Ltd.
6 */
7
8#include <linux/io.h>
9#include <linux/module.h>
10#include <linux/of.h>
11#include <linux/platform_device.h>
12#include <linux/rtc.h>
13#include <linux/goldfish.h>
14#include <clocksource/timer-goldfish.h>
15
16struct goldfish_rtc {
17	void __iomem *base;
18	int irq;
19	struct rtc_device *rtc;
20};
21
22static int goldfish_rtc_read_alarm(struct device *dev,
23				   struct rtc_wkalrm *alrm)
24{
25	u64 rtc_alarm;
26	u64 rtc_alarm_low;
27	u64 rtc_alarm_high;
28	void __iomem *base;
29	struct goldfish_rtc *rtcdrv;
30
31	rtcdrv = dev_get_drvdata(dev);
32	base = rtcdrv->base;
33
34	rtc_alarm_low = gf_ioread32(base + TIMER_ALARM_LOW);
35	rtc_alarm_high = gf_ioread32(base + TIMER_ALARM_HIGH);
36	rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
37
38	do_div(rtc_alarm, NSEC_PER_SEC);
39	memset(alrm, 0, sizeof(struct rtc_wkalrm));
40
41	rtc_time64_to_tm(rtc_alarm, &alrm->time);
42
43	if (gf_ioread32(base + TIMER_ALARM_STATUS))
44		alrm->enabled = 1;
45	else
46		alrm->enabled = 0;
47
48	return 0;
49}
50
51static int goldfish_rtc_set_alarm(struct device *dev,
52				  struct rtc_wkalrm *alrm)
53{
54	struct goldfish_rtc *rtcdrv;
55	u64 rtc_alarm64;
56	u64 rtc_status_reg;
57	void __iomem *base;
58
59	rtcdrv = dev_get_drvdata(dev);
60	base = rtcdrv->base;
61
62	if (alrm->enabled) {
63		rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
64		gf_iowrite32((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
65		gf_iowrite32(rtc_alarm64, base + TIMER_ALARM_LOW);
66		gf_iowrite32(1, base + TIMER_IRQ_ENABLED);
67	} else {
68		/*
69		 * if this function was called with enabled=0
70		 * then it could mean that the application is
71		 * trying to cancel an ongoing alarm
72		 */
73		rtc_status_reg = gf_ioread32(base + TIMER_ALARM_STATUS);
74		if (rtc_status_reg)
75			gf_iowrite32(1, base + TIMER_CLEAR_ALARM);
76	}
77
78	return 0;
79}
80
81static int goldfish_rtc_alarm_irq_enable(struct device *dev,
82					 unsigned int enabled)
83{
84	void __iomem *base;
85	struct goldfish_rtc *rtcdrv;
86
87	rtcdrv = dev_get_drvdata(dev);
88	base = rtcdrv->base;
89
90	if (enabled)
91		gf_iowrite32(1, base + TIMER_IRQ_ENABLED);
92	else
93		gf_iowrite32(0, base + TIMER_IRQ_ENABLED);
94
95	return 0;
96}
97
98static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
99{
100	struct goldfish_rtc *rtcdrv = dev_id;
101	void __iomem *base = rtcdrv->base;
102
103	gf_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);
104
105	rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
106
107	return IRQ_HANDLED;
108}
109
110static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
111{
112	struct goldfish_rtc *rtcdrv;
113	void __iomem *base;
114	u64 time_high;
115	u64 time_low;
116	u64 time;
117
118	rtcdrv = dev_get_drvdata(dev);
119	base = rtcdrv->base;
120
121	time_low = gf_ioread32(base + TIMER_TIME_LOW);
122	time_high = gf_ioread32(base + TIMER_TIME_HIGH);
123	time = (time_high << 32) | time_low;
124
125	do_div(time, NSEC_PER_SEC);
126
127	rtc_time64_to_tm(time, tm);
128
129	return 0;
130}
131
132static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
133{
134	struct goldfish_rtc *rtcdrv;
135	void __iomem *base;
136	u64 now64;
137
138	rtcdrv = dev_get_drvdata(dev);
139	base = rtcdrv->base;
140
141	now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
142	gf_iowrite32((now64 >> 32), base + TIMER_TIME_HIGH);
143	gf_iowrite32(now64, base + TIMER_TIME_LOW);
144
145	return 0;
146}
147
148static const struct rtc_class_ops goldfish_rtc_ops = {
149	.read_time	= goldfish_rtc_read_time,
150	.set_time	= goldfish_rtc_set_time,
151	.read_alarm	= goldfish_rtc_read_alarm,
152	.set_alarm	= goldfish_rtc_set_alarm,
153	.alarm_irq_enable = goldfish_rtc_alarm_irq_enable
154};
155
156static int goldfish_rtc_probe(struct platform_device *pdev)
157{
158	struct goldfish_rtc *rtcdrv;
159	int err;
160
161	rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
162	if (!rtcdrv)
163		return -ENOMEM;
164
165	platform_set_drvdata(pdev, rtcdrv);
166	rtcdrv->base = devm_platform_ioremap_resource(pdev, 0);
167	if (IS_ERR(rtcdrv->base))
168		return PTR_ERR(rtcdrv->base);
169
170	rtcdrv->irq = platform_get_irq(pdev, 0);
171	if (rtcdrv->irq < 0)
172		return -ENODEV;
173
174	rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
175	if (IS_ERR(rtcdrv->rtc))
176		return PTR_ERR(rtcdrv->rtc);
177
178	rtcdrv->rtc->ops = &goldfish_rtc_ops;
179	rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
180
181	err = devm_request_irq(&pdev->dev, rtcdrv->irq,
182			       goldfish_rtc_interrupt,
183			       0, pdev->name, rtcdrv);
184	if (err)
185		return err;
186
187	return devm_rtc_register_device(rtcdrv->rtc);
188}
189
190static const struct of_device_id goldfish_rtc_of_match[] = {
191	{ .compatible = "google,goldfish-rtc", },
192	{},
193};
194MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
195
196static struct platform_driver goldfish_rtc = {
197	.probe = goldfish_rtc_probe,
198	.driver = {
199		.name = "goldfish_rtc",
200		.of_match_table = goldfish_rtc_of_match,
201	}
202};
203
204module_platform_driver(goldfish_rtc);
205
206MODULE_LICENSE("GPL v2");
207