xref: /openbmc/linux/drivers/watchdog/sunxi_wdt.c (revision 981ab3f1)
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/delay.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26 #include <linux/platform_device.h>
27 #include <linux/types.h>
28 #include <linux/watchdog.h>
29 
30 #define WDT_MAX_TIMEOUT         16
31 #define WDT_MIN_TIMEOUT         1
32 #define WDT_TIMEOUT_MASK        0x0F
33 
34 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
35 
36 #define WDT_MODE_EN             (1 << 0)
37 
38 #define DRV_NAME		"sunxi-wdt"
39 #define DRV_VERSION		"1.0"
40 
41 static bool nowayout = WATCHDOG_NOWAYOUT;
42 static unsigned int timeout = WDT_MAX_TIMEOUT;
43 
44 /*
45  * This structure stores the register offsets for different variants
46  * of Allwinner's watchdog hardware.
47  */
48 struct sunxi_wdt_reg {
49 	u8 wdt_ctrl;
50 	u8 wdt_cfg;
51 	u8 wdt_mode;
52 	u8 wdt_timeout_shift;
53 	u8 wdt_reset_mask;
54 	u8 wdt_reset_val;
55 };
56 
57 struct sunxi_wdt_dev {
58 	struct watchdog_device wdt_dev;
59 	void __iomem *wdt_base;
60 	const struct sunxi_wdt_reg *wdt_regs;
61 };
62 
63 /*
64  * wdt_timeout_map maps the watchdog timer interval value in seconds to
65  * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
66  *
67  * [timeout seconds] = register value
68  *
69  */
70 
71 static const int wdt_timeout_map[] = {
72 	[1] = 0x1,  /* 1s  */
73 	[2] = 0x2,  /* 2s  */
74 	[3] = 0x3,  /* 3s  */
75 	[4] = 0x4,  /* 4s  */
76 	[5] = 0x5,  /* 5s  */
77 	[6] = 0x6,  /* 6s  */
78 	[8] = 0x7,  /* 8s  */
79 	[10] = 0x8, /* 10s */
80 	[12] = 0x9, /* 12s */
81 	[14] = 0xA, /* 14s */
82 	[16] = 0xB, /* 16s */
83 };
84 
85 
86 static int sunxi_wdt_restart(struct watchdog_device *wdt_dev,
87 			     unsigned long action, void *data)
88 {
89 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
90 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
91 	const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
92 	u32 val;
93 
94 	/* Set system reset function */
95 	val = readl(wdt_base + regs->wdt_cfg);
96 	val &= ~(regs->wdt_reset_mask);
97 	val |= regs->wdt_reset_val;
98 	writel(val, wdt_base + regs->wdt_cfg);
99 
100 	/* Set lowest timeout and enable watchdog */
101 	val = readl(wdt_base + regs->wdt_mode);
102 	val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
103 	val |= WDT_MODE_EN;
104 	writel(val, wdt_base + regs->wdt_mode);
105 
106 	/*
107 	 * Restart the watchdog. The default (and lowest) interval
108 	 * value for the watchdog is 0.5s.
109 	 */
110 	writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
111 
112 	while (1) {
113 		mdelay(5);
114 		val = readl(wdt_base + regs->wdt_mode);
115 		val |= WDT_MODE_EN;
116 		writel(val, wdt_base + regs->wdt_mode);
117 	}
118 	return 0;
119 }
120 
121 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
122 {
123 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
124 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
125 	const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
126 
127 	writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
128 
129 	return 0;
130 }
131 
132 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
133 		unsigned int timeout)
134 {
135 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
136 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
137 	const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
138 	u32 reg;
139 
140 	if (wdt_timeout_map[timeout] == 0)
141 		timeout++;
142 
143 	sunxi_wdt->wdt_dev.timeout = timeout;
144 
145 	reg = readl(wdt_base + regs->wdt_mode);
146 	reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
147 	reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
148 	writel(reg, wdt_base + regs->wdt_mode);
149 
150 	sunxi_wdt_ping(wdt_dev);
151 
152 	return 0;
153 }
154 
155 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
156 {
157 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
158 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
159 	const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
160 
161 	writel(0, wdt_base + regs->wdt_mode);
162 
163 	return 0;
164 }
165 
166 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
167 {
168 	u32 reg;
169 	struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
170 	void __iomem *wdt_base = sunxi_wdt->wdt_base;
171 	const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
172 	int ret;
173 
174 	ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
175 			sunxi_wdt->wdt_dev.timeout);
176 	if (ret < 0)
177 		return ret;
178 
179 	/* Set system reset function */
180 	reg = readl(wdt_base + regs->wdt_cfg);
181 	reg &= ~(regs->wdt_reset_mask);
182 	reg |= regs->wdt_reset_val;
183 	writel(reg, wdt_base + regs->wdt_cfg);
184 
185 	/* Enable watchdog */
186 	reg = readl(wdt_base + regs->wdt_mode);
187 	reg |= WDT_MODE_EN;
188 	writel(reg, wdt_base + regs->wdt_mode);
189 
190 	return 0;
191 }
192 
193 static const struct watchdog_info sunxi_wdt_info = {
194 	.identity	= DRV_NAME,
195 	.options	= WDIOF_SETTIMEOUT |
196 			  WDIOF_KEEPALIVEPING |
197 			  WDIOF_MAGICCLOSE,
198 };
199 
200 static const struct watchdog_ops sunxi_wdt_ops = {
201 	.owner		= THIS_MODULE,
202 	.start		= sunxi_wdt_start,
203 	.stop		= sunxi_wdt_stop,
204 	.ping		= sunxi_wdt_ping,
205 	.set_timeout	= sunxi_wdt_set_timeout,
206 	.restart	= sunxi_wdt_restart,
207 };
208 
209 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
210 	.wdt_ctrl = 0x00,
211 	.wdt_cfg = 0x04,
212 	.wdt_mode = 0x04,
213 	.wdt_timeout_shift = 3,
214 	.wdt_reset_mask = 0x02,
215 	.wdt_reset_val = 0x02,
216 };
217 
218 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
219 	.wdt_ctrl = 0x10,
220 	.wdt_cfg = 0x14,
221 	.wdt_mode = 0x18,
222 	.wdt_timeout_shift = 4,
223 	.wdt_reset_mask = 0x03,
224 	.wdt_reset_val = 0x01,
225 };
226 
227 static const struct of_device_id sunxi_wdt_dt_ids[] = {
228 	{ .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
229 	{ .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
230 	{ /* sentinel */ }
231 };
232 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
233 
234 static int sunxi_wdt_probe(struct platform_device *pdev)
235 {
236 	struct sunxi_wdt_dev *sunxi_wdt;
237 	const struct of_device_id *device;
238 	struct resource *res;
239 	int err;
240 
241 	sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
242 	if (!sunxi_wdt)
243 		return -EINVAL;
244 
245 	device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
246 	if (!device)
247 		return -ENODEV;
248 
249 	sunxi_wdt->wdt_regs = device->data;
250 
251 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
252 	sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
253 	if (IS_ERR(sunxi_wdt->wdt_base))
254 		return PTR_ERR(sunxi_wdt->wdt_base);
255 
256 	sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
257 	sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
258 	sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
259 	sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
260 	sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
261 	sunxi_wdt->wdt_dev.parent = &pdev->dev;
262 
263 	watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
264 	watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
265 	watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128);
266 
267 	watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
268 
269 	sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
270 
271 	watchdog_stop_on_reboot(&sunxi_wdt->wdt_dev);
272 	err = devm_watchdog_register_device(&pdev->dev, &sunxi_wdt->wdt_dev);
273 	if (unlikely(err))
274 		return err;
275 
276 	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
277 			sunxi_wdt->wdt_dev.timeout, nowayout);
278 
279 	return 0;
280 }
281 
282 static struct platform_driver sunxi_wdt_driver = {
283 	.probe		= sunxi_wdt_probe,
284 	.driver		= {
285 		.name		= DRV_NAME,
286 		.of_match_table	= sunxi_wdt_dt_ids,
287 	},
288 };
289 
290 module_platform_driver(sunxi_wdt_driver);
291 
292 module_param(timeout, uint, 0);
293 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
294 
295 module_param(nowayout, bool, 0);
296 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
297 		"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
298 
299 MODULE_LICENSE("GPL");
300 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
301 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
302 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
303 MODULE_VERSION(DRV_VERSION);
304