1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * sunxi Watchdog Driver
4 *
5 * Copyright (c) 2013 Carlo Caione
6 * 2012 Henrik Nordstrom
7 *
8 * Based on xen_wdt.c
9 * (c) Copyright 2010 Novell, Inc.
10 */
11
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/of.h>
21 #include <linux/of_device.h>
22 #include <linux/platform_device.h>
23 #include <linux/types.h>
24 #include <linux/watchdog.h>
25
26 #define WDT_MAX_TIMEOUT 16
27 #define WDT_MIN_TIMEOUT 1
28 #define WDT_TIMEOUT_MASK 0x0F
29
30 #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1))
31
32 #define WDT_MODE_EN (1 << 0)
33
34 #define DRV_NAME "sunxi-wdt"
35 #define DRV_VERSION "1.0"
36
37 static bool nowayout = WATCHDOG_NOWAYOUT;
38 static unsigned int timeout;
39
40 /*
41 * This structure stores the register offsets for different variants
42 * of Allwinner's watchdog hardware.
43 */
44 struct sunxi_wdt_reg {
45 u8 wdt_ctrl;
46 u8 wdt_cfg;
47 u8 wdt_mode;
48 u8 wdt_timeout_shift;
49 u8 wdt_reset_mask;
50 u8 wdt_reset_val;
51 u32 wdt_key_val;
52 };
53
54 struct sunxi_wdt_dev {
55 struct watchdog_device wdt_dev;
56 void __iomem *wdt_base;
57 const struct sunxi_wdt_reg *wdt_regs;
58 };
59
60 /*
61 * wdt_timeout_map maps the watchdog timer interval value in seconds to
62 * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
63 *
64 * [timeout seconds] = register value
65 *
66 */
67
68 static const int wdt_timeout_map[] = {
69 [1] = 0x1, /* 1s */
70 [2] = 0x2, /* 2s */
71 [3] = 0x3, /* 3s */
72 [4] = 0x4, /* 4s */
73 [5] = 0x5, /* 5s */
74 [6] = 0x6, /* 6s */
75 [8] = 0x7, /* 8s */
76 [10] = 0x8, /* 10s */
77 [12] = 0x9, /* 12s */
78 [14] = 0xA, /* 14s */
79 [16] = 0xB, /* 16s */
80 };
81
82
sunxi_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)83 static int sunxi_wdt_restart(struct watchdog_device *wdt_dev,
84 unsigned long action, void *data)
85 {
86 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
87 void __iomem *wdt_base = sunxi_wdt->wdt_base;
88 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
89 u32 val;
90
91 /* Set system reset function */
92 val = readl(wdt_base + regs->wdt_cfg);
93 val &= ~(regs->wdt_reset_mask);
94 val |= regs->wdt_reset_val;
95 val |= regs->wdt_key_val;
96 writel(val, wdt_base + regs->wdt_cfg);
97
98 /* Set lowest timeout and enable watchdog */
99 val = readl(wdt_base + regs->wdt_mode);
100 val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
101 val |= WDT_MODE_EN;
102 val |= regs->wdt_key_val;
103 writel(val, wdt_base + regs->wdt_mode);
104
105 /*
106 * Restart the watchdog. The default (and lowest) interval
107 * value for the watchdog is 0.5s.
108 */
109 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
110
111 while (1) {
112 mdelay(5);
113 val = readl(wdt_base + regs->wdt_mode);
114 val |= WDT_MODE_EN;
115 val |= regs->wdt_key_val;
116 writel(val, wdt_base + regs->wdt_mode);
117 }
118 return 0;
119 }
120
sunxi_wdt_ping(struct watchdog_device * wdt_dev)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
sunxi_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)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 reg |= regs->wdt_key_val;
149 writel(reg, wdt_base + regs->wdt_mode);
150
151 sunxi_wdt_ping(wdt_dev);
152
153 return 0;
154 }
155
sunxi_wdt_stop(struct watchdog_device * wdt_dev)156 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
157 {
158 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
159 void __iomem *wdt_base = sunxi_wdt->wdt_base;
160 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
161
162 writel(regs->wdt_key_val, wdt_base + regs->wdt_mode);
163
164 return 0;
165 }
166
sunxi_wdt_start(struct watchdog_device * wdt_dev)167 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
168 {
169 u32 reg;
170 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
171 void __iomem *wdt_base = sunxi_wdt->wdt_base;
172 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
173 int ret;
174
175 ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
176 sunxi_wdt->wdt_dev.timeout);
177 if (ret < 0)
178 return ret;
179
180 /* Set system reset function */
181 reg = readl(wdt_base + regs->wdt_cfg);
182 reg &= ~(regs->wdt_reset_mask);
183 reg |= regs->wdt_reset_val;
184 reg |= regs->wdt_key_val;
185 writel(reg, wdt_base + regs->wdt_cfg);
186
187 /* Enable watchdog */
188 reg = readl(wdt_base + regs->wdt_mode);
189 reg |= WDT_MODE_EN;
190 reg |= regs->wdt_key_val;
191 writel(reg, wdt_base + regs->wdt_mode);
192
193 return 0;
194 }
195
196 static const struct watchdog_info sunxi_wdt_info = {
197 .identity = DRV_NAME,
198 .options = WDIOF_SETTIMEOUT |
199 WDIOF_KEEPALIVEPING |
200 WDIOF_MAGICCLOSE,
201 };
202
203 static const struct watchdog_ops sunxi_wdt_ops = {
204 .owner = THIS_MODULE,
205 .start = sunxi_wdt_start,
206 .stop = sunxi_wdt_stop,
207 .ping = sunxi_wdt_ping,
208 .set_timeout = sunxi_wdt_set_timeout,
209 .restart = sunxi_wdt_restart,
210 };
211
212 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
213 .wdt_ctrl = 0x00,
214 .wdt_cfg = 0x04,
215 .wdt_mode = 0x04,
216 .wdt_timeout_shift = 3,
217 .wdt_reset_mask = 0x02,
218 .wdt_reset_val = 0x02,
219 };
220
221 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
222 .wdt_ctrl = 0x10,
223 .wdt_cfg = 0x14,
224 .wdt_mode = 0x18,
225 .wdt_timeout_shift = 4,
226 .wdt_reset_mask = 0x03,
227 .wdt_reset_val = 0x01,
228 };
229
230 static const struct sunxi_wdt_reg sun20i_wdt_reg = {
231 .wdt_ctrl = 0x10,
232 .wdt_cfg = 0x14,
233 .wdt_mode = 0x18,
234 .wdt_timeout_shift = 4,
235 .wdt_reset_mask = 0x03,
236 .wdt_reset_val = 0x01,
237 .wdt_key_val = 0x16aa0000,
238 };
239
240 static const struct of_device_id sunxi_wdt_dt_ids[] = {
241 { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
242 { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
243 { .compatible = "allwinner,sun20i-d1-wdt", .data = &sun20i_wdt_reg },
244 { /* sentinel */ }
245 };
246 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
247
sunxi_wdt_probe(struct platform_device * pdev)248 static int sunxi_wdt_probe(struct platform_device *pdev)
249 {
250 struct device *dev = &pdev->dev;
251 struct sunxi_wdt_dev *sunxi_wdt;
252 int err;
253
254 sunxi_wdt = devm_kzalloc(dev, sizeof(*sunxi_wdt), GFP_KERNEL);
255 if (!sunxi_wdt)
256 return -ENOMEM;
257
258 sunxi_wdt->wdt_regs = of_device_get_match_data(dev);
259 if (!sunxi_wdt->wdt_regs)
260 return -ENODEV;
261
262 sunxi_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
263 if (IS_ERR(sunxi_wdt->wdt_base))
264 return PTR_ERR(sunxi_wdt->wdt_base);
265
266 sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
267 sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
268 sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
269 sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
270 sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
271 sunxi_wdt->wdt_dev.parent = dev;
272
273 watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, dev);
274 watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
275 watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128);
276
277 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
278
279 sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
280
281 watchdog_stop_on_reboot(&sunxi_wdt->wdt_dev);
282 err = devm_watchdog_register_device(dev, &sunxi_wdt->wdt_dev);
283 if (unlikely(err))
284 return err;
285
286 dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
287 sunxi_wdt->wdt_dev.timeout, nowayout);
288
289 return 0;
290 }
291
292 static struct platform_driver sunxi_wdt_driver = {
293 .probe = sunxi_wdt_probe,
294 .driver = {
295 .name = DRV_NAME,
296 .of_match_table = sunxi_wdt_dt_ids,
297 },
298 };
299
300 module_platform_driver(sunxi_wdt_driver);
301
302 module_param(timeout, uint, 0);
303 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
304
305 module_param(nowayout, bool, 0);
306 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
307 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
308
309 MODULE_LICENSE("GPL");
310 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
311 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
312 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
313 MODULE_VERSION(DRV_VERSION);
314