xref: /openbmc/linux/drivers/watchdog/meson_wdt.c (revision cc85f87a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *      Meson Watchdog Driver
4  *
5  *      Copyright (c) 2014 Carlo Caione
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/kernel.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/module.h>
16 #include <linux/moduleparam.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19 #include <linux/types.h>
20 #include <linux/watchdog.h>
21 
22 #define DRV_NAME		"meson_wdt"
23 
24 #define MESON_WDT_TC		0x00
25 #define MESON_WDT_DC_RESET	(3 << 24)
26 
27 #define MESON_WDT_RESET		0x04
28 
29 #define MESON_WDT_TIMEOUT	30
30 #define MESON_WDT_MIN_TIMEOUT	1
31 
32 #define MESON_SEC_TO_TC(s, c)	((s) * (c))
33 
34 static bool nowayout = WATCHDOG_NOWAYOUT;
35 static unsigned int timeout;
36 
37 struct meson_wdt_data {
38 	unsigned int enable;
39 	unsigned int terminal_count_mask;
40 	unsigned int count_unit;
41 };
42 
43 static struct meson_wdt_data meson6_wdt_data = {
44 	.enable			= BIT(22),
45 	.terminal_count_mask	= 0x3fffff,
46 	.count_unit		= 100000, /* 10 us */
47 };
48 
49 static struct meson_wdt_data meson8b_wdt_data = {
50 	.enable			= BIT(19),
51 	.terminal_count_mask	= 0xffff,
52 	.count_unit		= 7812, /* 128 us */
53 };
54 
55 struct meson_wdt_dev {
56 	struct watchdog_device wdt_dev;
57 	void __iomem *wdt_base;
58 	const struct meson_wdt_data *data;
59 };
60 
meson_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)61 static int meson_wdt_restart(struct watchdog_device *wdt_dev,
62 			     unsigned long action, void *data)
63 {
64 	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
65 	u32 tc_reboot = MESON_WDT_DC_RESET;
66 
67 	tc_reboot |= meson_wdt->data->enable;
68 
69 	while (1) {
70 		writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
71 		mdelay(5);
72 	}
73 
74 	return 0;
75 }
76 
meson_wdt_ping(struct watchdog_device * wdt_dev)77 static int meson_wdt_ping(struct watchdog_device *wdt_dev)
78 {
79 	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
80 
81 	writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
82 
83 	return 0;
84 }
85 
meson_wdt_change_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)86 static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
87 				     unsigned int timeout)
88 {
89 	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
90 	u32 reg;
91 
92 	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
93 	reg &= ~meson_wdt->data->terminal_count_mask;
94 	reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
95 	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
96 }
97 
meson_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)98 static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
99 				 unsigned int timeout)
100 {
101 	wdt_dev->timeout = timeout;
102 
103 	meson_wdt_change_timeout(wdt_dev, timeout);
104 	meson_wdt_ping(wdt_dev);
105 
106 	return 0;
107 }
108 
meson_wdt_stop(struct watchdog_device * wdt_dev)109 static int meson_wdt_stop(struct watchdog_device *wdt_dev)
110 {
111 	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
112 	u32 reg;
113 
114 	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
115 	reg &= ~meson_wdt->data->enable;
116 	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
117 
118 	return 0;
119 }
120 
meson_wdt_start(struct watchdog_device * wdt_dev)121 static int meson_wdt_start(struct watchdog_device *wdt_dev)
122 {
123 	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
124 	u32 reg;
125 
126 	meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
127 	meson_wdt_ping(wdt_dev);
128 
129 	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
130 	reg |= meson_wdt->data->enable;
131 	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
132 
133 	return 0;
134 }
135 
136 static const struct watchdog_info meson_wdt_info = {
137 	.identity	= DRV_NAME,
138 	.options	= WDIOF_SETTIMEOUT |
139 			  WDIOF_KEEPALIVEPING |
140 			  WDIOF_MAGICCLOSE,
141 };
142 
143 static const struct watchdog_ops meson_wdt_ops = {
144 	.owner		= THIS_MODULE,
145 	.start		= meson_wdt_start,
146 	.stop		= meson_wdt_stop,
147 	.ping		= meson_wdt_ping,
148 	.set_timeout	= meson_wdt_set_timeout,
149 	.restart        = meson_wdt_restart,
150 };
151 
152 static const struct of_device_id meson_wdt_dt_ids[] = {
153 	{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
154 	{ .compatible = "amlogic,meson8-wdt", .data = &meson6_wdt_data },
155 	{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
156 	{ .compatible = "amlogic,meson8m2-wdt", .data = &meson8b_wdt_data },
157 	{ /* sentinel */ }
158 };
159 MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
160 
meson_wdt_probe(struct platform_device * pdev)161 static int meson_wdt_probe(struct platform_device *pdev)
162 {
163 	struct device *dev = &pdev->dev;
164 	struct meson_wdt_dev *meson_wdt;
165 	int err;
166 
167 	meson_wdt = devm_kzalloc(dev, sizeof(*meson_wdt), GFP_KERNEL);
168 	if (!meson_wdt)
169 		return -ENOMEM;
170 
171 	meson_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
172 	if (IS_ERR(meson_wdt->wdt_base))
173 		return PTR_ERR(meson_wdt->wdt_base);
174 
175 	meson_wdt->data = device_get_match_data(dev);
176 
177 	meson_wdt->wdt_dev.parent = dev;
178 	meson_wdt->wdt_dev.info = &meson_wdt_info;
179 	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
180 	meson_wdt->wdt_dev.max_timeout =
181 		meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
182 	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
183 	meson_wdt->wdt_dev.timeout = min_t(unsigned int,
184 					   MESON_WDT_TIMEOUT,
185 					   meson_wdt->wdt_dev.max_timeout);
186 
187 	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
188 
189 	watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, dev);
190 	watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
191 	watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);
192 
193 	meson_wdt_stop(&meson_wdt->wdt_dev);
194 
195 	watchdog_stop_on_reboot(&meson_wdt->wdt_dev);
196 	err = devm_watchdog_register_device(dev, &meson_wdt->wdt_dev);
197 	if (err)
198 		return err;
199 
200 	dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
201 		 meson_wdt->wdt_dev.timeout, nowayout);
202 
203 	return 0;
204 }
205 
206 static struct platform_driver meson_wdt_driver = {
207 	.probe		= meson_wdt_probe,
208 	.driver		= {
209 		.name		= DRV_NAME,
210 		.of_match_table	= meson_wdt_dt_ids,
211 	},
212 };
213 
214 module_platform_driver(meson_wdt_driver);
215 
216 module_param(timeout, uint, 0);
217 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
218 
219 module_param(nowayout, bool, 0);
220 MODULE_PARM_DESC(nowayout,
221 		 "Watchdog cannot be stopped once started (default="
222 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
223 
224 MODULE_LICENSE("GPL");
225 MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
226 MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
227