xref: /openbmc/linux/drivers/watchdog/sunxi_wdt.c (revision b34e08d5)
1 /*
2  *      sunxi Watchdog Driver
3  *
4  *      Copyright (c) 2013 Carlo Caione
5  *                    2012 Henrik Nordstrom
6  *
7  *      This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License
9  *      as published by the Free Software Foundation; either version
10  *      2 of the License, or (at your option) any later version.
11  *
12  *      Based on xen_wdt.c
13  *      (c) Copyright 2010 Novell, Inc.
14  */
15 
16 #include <linux/clk.h>
17 #include <linux/err.h>
18 #include <linux/init.h>
19 #include <linux/io.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/of.h>
24 #include <linux/platform_device.h>
25 #include <linux/types.h>
26 #include <linux/watchdog.h>
27 
28 #define WDT_MAX_TIMEOUT         16
29 #define WDT_MIN_TIMEOUT         1
30 #define WDT_MODE_TIMEOUT(n)     ((n) << 3)
31 #define WDT_TIMEOUT_MASK        WDT_MODE_TIMEOUT(0x0F)
32 
33 #define WDT_CTRL                0x00
34 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
35 
36 #define WDT_MODE                0x04
37 #define WDT_MODE_EN             (1 << 0)
38 #define WDT_MODE_RST_EN         (1 << 1)
39 
40 #define DRV_NAME		"sunxi-wdt"
41 #define DRV_VERSION		"1.0"
42 
43 static bool nowayout = WATCHDOG_NOWAYOUT;
44 static unsigned int timeout = WDT_MAX_TIMEOUT;
45 
46 struct sunxi_wdt_dev {
47 	struct watchdog_device wdt_dev;
48 	void __iomem *wdt_base;
49 };
50 
51 /*
52  * wdt_timeout_map maps the watchdog timer interval value in seconds to
53  * the value of the register WDT_MODE bit 3:6
54  *
55  * [timeout seconds] = register value
56  *
57  */
58 
59 static const int wdt_timeout_map[] = {
60 	[1] = 0b0001,  /* 1s  */
61 	[2] = 0b0010,  /* 2s  */
62 	[3] = 0b0011,  /* 3s  */
63 	[4] = 0b0100,  /* 4s  */
64 	[5] = 0b0101,  /* 5s  */
65 	[6] = 0b0110,  /* 6s  */
66 	[8] = 0b0111,  /* 8s  */
67 	[10] = 0b1000, /* 10s */
68 	[12] = 0b1001, /* 12s */
69 	[14] = 0b1010, /* 14s */
70 	[16] = 0b1011, /* 16s */
71 };
72 
73 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
74 {
75 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
76 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
77 
78 	iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
79 
80 	return 0;
81 }
82 
83 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
84 		unsigned int timeout)
85 {
86 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
87 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
88 	u32 reg;
89 
90 	if (wdt_timeout_map[timeout] == 0)
91 		timeout++;
92 
93 	sunxi_wdt->wdt_dev.timeout = timeout;
94 
95 	reg = ioread32(wdt_base + WDT_MODE);
96 	reg &= ~WDT_TIMEOUT_MASK;
97 	reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]);
98 	iowrite32(reg, wdt_base + WDT_MODE);
99 
100 	sunxi_wdt_ping(wdt_dev);
101 
102 	return 0;
103 }
104 
105 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
106 {
107 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
108 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
109 
110 	iowrite32(0, wdt_base + WDT_MODE);
111 
112 	return 0;
113 }
114 
115 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
116 {
117 	u32 reg;
118 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
119 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
120 	int ret;
121 
122 	ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
123 			sunxi_wdt->wdt_dev.timeout);
124 	if (ret < 0)
125 		return ret;
126 
127 	reg = ioread32(wdt_base + WDT_MODE);
128 	reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
129 	iowrite32(reg, wdt_base + WDT_MODE);
130 
131 	return 0;
132 }
133 
134 static const struct watchdog_info sunxi_wdt_info = {
135 	.identity	= DRV_NAME,
136 	.options	= WDIOF_SETTIMEOUT |
137 			  WDIOF_KEEPALIVEPING |
138 			  WDIOF_MAGICCLOSE,
139 };
140 
141 static const struct watchdog_ops sunxi_wdt_ops = {
142 	.owner		= THIS_MODULE,
143 	.start		= sunxi_wdt_start,
144 	.stop		= sunxi_wdt_stop,
145 	.ping		= sunxi_wdt_ping,
146 	.set_timeout	= sunxi_wdt_set_timeout,
147 };
148 
149 static int sunxi_wdt_probe(struct platform_device *pdev)
150 {
151 	struct sunxi_wdt_dev *sunxi_wdt;
152 	struct resource *res;
153 	int err;
154 
155 	sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
156 	if (!sunxi_wdt)
157 		return -EINVAL;
158 
159 	platform_set_drvdata(pdev, sunxi_wdt);
160 
161 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
162 	sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
163 	if (IS_ERR(sunxi_wdt->wdt_base))
164 		return PTR_ERR(sunxi_wdt->wdt_base);
165 
166 	sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
167 	sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
168 	sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
169 	sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
170 	sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
171 	sunxi_wdt->wdt_dev.parent = &pdev->dev;
172 
173 	watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
174 	watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
175 
176 	watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
177 
178 	sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
179 
180 	err = watchdog_register_device(&sunxi_wdt->wdt_dev);
181 	if (unlikely(err))
182 		return err;
183 
184 	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
185 			sunxi_wdt->wdt_dev.timeout, nowayout);
186 
187 	return 0;
188 }
189 
190 static int sunxi_wdt_remove(struct platform_device *pdev)
191 {
192 	struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
193 
194 	watchdog_unregister_device(&sunxi_wdt->wdt_dev);
195 	watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
196 
197 	return 0;
198 }
199 
200 static void sunxi_wdt_shutdown(struct platform_device *pdev)
201 {
202 	struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
203 
204 	sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
205 }
206 
207 static const struct of_device_id sunxi_wdt_dt_ids[] = {
208 	{ .compatible = "allwinner,sun4i-a10-wdt" },
209 	{ /* sentinel */ }
210 };
211 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
212 
213 static struct platform_driver sunxi_wdt_driver = {
214 	.probe		= sunxi_wdt_probe,
215 	.remove		= sunxi_wdt_remove,
216 	.shutdown	= sunxi_wdt_shutdown,
217 	.driver		= {
218 		.owner		= THIS_MODULE,
219 		.name		= DRV_NAME,
220 		.of_match_table	= sunxi_wdt_dt_ids,
221 	},
222 };
223 
224 module_platform_driver(sunxi_wdt_driver);
225 
226 module_param(timeout, uint, 0);
227 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
228 
229 module_param(nowayout, bool, 0);
230 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
231 		"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
232 
233 MODULE_LICENSE("GPL");
234 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
235 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
236 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
237 MODULE_VERSION(DRV_VERSION);
238