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/platform_device.h>
22 #include <linux/types.h>
23 #include <linux/watchdog.h>
24
25 #define WDT_MAX_TIMEOUT 16
26 #define WDT_MIN_TIMEOUT 1
27 #define WDT_TIMEOUT_MASK 0x0F
28
29 #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1))
30
31 #define WDT_MODE_EN (1 << 0)
32
33 #define DRV_NAME "sunxi-wdt"
34 #define DRV_VERSION "1.0"
35
36 static bool nowayout = WATCHDOG_NOWAYOUT;
37 static unsigned int timeout;
38
39 /*
40 * This structure stores the register offsets for different variants
41 * of Allwinner's watchdog hardware.
42 */
43 struct sunxi_wdt_reg {
44 u8 wdt_ctrl;
45 u8 wdt_cfg;
46 u8 wdt_mode;
47 u8 wdt_timeout_shift;
48 u8 wdt_reset_mask;
49 u8 wdt_reset_val;
50 u32 wdt_key_val;
51 };
52
53 struct sunxi_wdt_dev {
54 struct watchdog_device wdt_dev;
55 void __iomem *wdt_base;
56 const struct sunxi_wdt_reg *wdt_regs;
57 };
58
59 /*
60 * wdt_timeout_map maps the watchdog timer interval value in seconds to
61 * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
62 *
63 * [timeout seconds] = register value
64 *
65 */
66
67 static const int wdt_timeout_map[] = {
68 [1] = 0x1, /* 1s */
69 [2] = 0x2, /* 2s */
70 [3] = 0x3, /* 3s */
71 [4] = 0x4, /* 4s */
72 [5] = 0x5, /* 5s */
73 [6] = 0x6, /* 6s */
74 [8] = 0x7, /* 8s */
75 [10] = 0x8, /* 10s */
76 [12] = 0x9, /* 12s */
77 [14] = 0xA, /* 14s */
78 [16] = 0xB, /* 16s */
79 };
80
81
sunxi_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)82 static int sunxi_wdt_restart(struct watchdog_device *wdt_dev,
83 unsigned long action, void *data)
84 {
85 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
86 void __iomem *wdt_base = sunxi_wdt->wdt_base;
87 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
88 u32 val;
89
90 /* Set system reset function */
91 val = readl(wdt_base + regs->wdt_cfg);
92 val &= ~(regs->wdt_reset_mask);
93 val |= regs->wdt_reset_val;
94 val |= regs->wdt_key_val;
95 writel(val, wdt_base + regs->wdt_cfg);
96
97 /* Set lowest timeout and enable watchdog */
98 val = readl(wdt_base + regs->wdt_mode);
99 val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
100 val |= WDT_MODE_EN;
101 val |= regs->wdt_key_val;
102 writel(val, wdt_base + regs->wdt_mode);
103
104 /*
105 * Restart the watchdog. The default (and lowest) interval
106 * value for the watchdog is 0.5s.
107 */
108 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
109
110 while (1) {
111 mdelay(5);
112 val = readl(wdt_base + regs->wdt_mode);
113 val |= WDT_MODE_EN;
114 val |= regs->wdt_key_val;
115 writel(val, wdt_base + regs->wdt_mode);
116 }
117 return 0;
118 }
119
sunxi_wdt_ping(struct watchdog_device * wdt_dev)120 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
121 {
122 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
123 void __iomem *wdt_base = sunxi_wdt->wdt_base;
124 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
125
126 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
127
128 return 0;
129 }
130
sunxi_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)131 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
132 unsigned int timeout)
133 {
134 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
135 void __iomem *wdt_base = sunxi_wdt->wdt_base;
136 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
137 u32 reg;
138
139 if (wdt_timeout_map[timeout] == 0)
140 timeout++;
141
142 sunxi_wdt->wdt_dev.timeout = timeout;
143
144 reg = readl(wdt_base + regs->wdt_mode);
145 reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
146 reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
147 reg |= regs->wdt_key_val;
148 writel(reg, wdt_base + regs->wdt_mode);
149
150 sunxi_wdt_ping(wdt_dev);
151
152 return 0;
153 }
154
sunxi_wdt_stop(struct watchdog_device * wdt_dev)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(regs->wdt_key_val, wdt_base + regs->wdt_mode);
162
163 return 0;
164 }
165
sunxi_wdt_start(struct watchdog_device * wdt_dev)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 reg |= regs->wdt_key_val;
184 writel(reg, wdt_base + regs->wdt_cfg);
185
186 /* Enable watchdog */
187 reg = readl(wdt_base + regs->wdt_mode);
188 reg |= WDT_MODE_EN;
189 reg |= regs->wdt_key_val;
190 writel(reg, wdt_base + regs->wdt_mode);
191
192 return 0;
193 }
194
195 static const struct watchdog_info sunxi_wdt_info = {
196 .identity = DRV_NAME,
197 .options = WDIOF_SETTIMEOUT |
198 WDIOF_KEEPALIVEPING |
199 WDIOF_MAGICCLOSE,
200 };
201
202 static const struct watchdog_ops sunxi_wdt_ops = {
203 .owner = THIS_MODULE,
204 .start = sunxi_wdt_start,
205 .stop = sunxi_wdt_stop,
206 .ping = sunxi_wdt_ping,
207 .set_timeout = sunxi_wdt_set_timeout,
208 .restart = sunxi_wdt_restart,
209 };
210
211 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
212 .wdt_ctrl = 0x00,
213 .wdt_cfg = 0x04,
214 .wdt_mode = 0x04,
215 .wdt_timeout_shift = 3,
216 .wdt_reset_mask = 0x02,
217 .wdt_reset_val = 0x02,
218 };
219
220 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
221 .wdt_ctrl = 0x10,
222 .wdt_cfg = 0x14,
223 .wdt_mode = 0x18,
224 .wdt_timeout_shift = 4,
225 .wdt_reset_mask = 0x03,
226 .wdt_reset_val = 0x01,
227 };
228
229 static const struct sunxi_wdt_reg sun20i_wdt_reg = {
230 .wdt_ctrl = 0x10,
231 .wdt_cfg = 0x14,
232 .wdt_mode = 0x18,
233 .wdt_timeout_shift = 4,
234 .wdt_reset_mask = 0x03,
235 .wdt_reset_val = 0x01,
236 .wdt_key_val = 0x16aa0000,
237 };
238
239 static const struct of_device_id sunxi_wdt_dt_ids[] = {
240 { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
241 { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
242 { .compatible = "allwinner,sun20i-d1-wdt", .data = &sun20i_wdt_reg },
243 { /* sentinel */ }
244 };
245 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
246
sunxi_wdt_probe(struct platform_device * pdev)247 static int sunxi_wdt_probe(struct platform_device *pdev)
248 {
249 struct device *dev = &pdev->dev;
250 struct sunxi_wdt_dev *sunxi_wdt;
251 int err;
252
253 sunxi_wdt = devm_kzalloc(dev, sizeof(*sunxi_wdt), GFP_KERNEL);
254 if (!sunxi_wdt)
255 return -ENOMEM;
256
257 sunxi_wdt->wdt_regs = of_device_get_match_data(dev);
258 if (!sunxi_wdt->wdt_regs)
259 return -ENODEV;
260
261 sunxi_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
262 if (IS_ERR(sunxi_wdt->wdt_base))
263 return PTR_ERR(sunxi_wdt->wdt_base);
264
265 sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
266 sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
267 sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
268 sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
269 sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
270 sunxi_wdt->wdt_dev.parent = dev;
271
272 watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, dev);
273 watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
274 watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128);
275
276 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
277
278 sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
279
280 watchdog_stop_on_reboot(&sunxi_wdt->wdt_dev);
281 err = devm_watchdog_register_device(dev, &sunxi_wdt->wdt_dev);
282 if (unlikely(err))
283 return err;
284
285 dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
286 sunxi_wdt->wdt_dev.timeout, nowayout);
287
288 return 0;
289 }
290
291 static struct platform_driver sunxi_wdt_driver = {
292 .probe = sunxi_wdt_probe,
293 .driver = {
294 .name = DRV_NAME,
295 .of_match_table = sunxi_wdt_dt_ids,
296 },
297 };
298
299 module_platform_driver(sunxi_wdt_driver);
300
301 module_param(timeout, uint, 0);
302 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
303
304 module_param(nowayout, bool, 0);
305 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
306 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
307
308 MODULE_LICENSE("GPL");
309 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
310 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
311 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
312 MODULE_VERSION(DRV_VERSION);
313