This source file includes following definitions.
- at91rm9200_restart
- at91_wdt_stop
- at91_wdt_start
- at91_wdt_reload
- at91_wdt_open
- at91_wdt_close
- at91_wdt_settimeout
- at91_wdt_ioctl
- at91_wdt_write
- at91wdt_probe
- at91wdt_remove
- at91wdt_shutdown
- at91wdt_suspend
- at91wdt_resume
- at91_wdt_init
- at91_wdt_exit
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8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/bitops.h>
12 #include <linux/delay.h>
13 #include <linux/errno.h>
14 #include <linux/fs.h>
15 #include <linux/init.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/syscon.h>
19 #include <linux/mfd/syscon/atmel-st.h>
20 #include <linux/miscdevice.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/platform_device.h>
24 #include <linux/reboot.h>
25 #include <linux/regmap.h>
26 #include <linux/types.h>
27 #include <linux/watchdog.h>
28 #include <linux/uaccess.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31
32 #define WDT_DEFAULT_TIME 5
33 #define WDT_MAX_TIME 256
34
35 static int wdt_time = WDT_DEFAULT_TIME;
36 static bool nowayout = WATCHDOG_NOWAYOUT;
37 static struct regmap *regmap_st;
38
39 module_param(wdt_time, int, 0);
40 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
41 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
42
43 #ifdef CONFIG_WATCHDOG_NOWAYOUT
44 module_param(nowayout, bool, 0);
45 MODULE_PARM_DESC(nowayout,
46 "Watchdog cannot be stopped once started (default="
47 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48 #endif
49
50
51 static unsigned long at91wdt_busy;
52
53
54
55 static int at91rm9200_restart(struct notifier_block *this,
56 unsigned long mode, void *cmd)
57 {
58
59
60
61 regmap_write(regmap_st, AT91_ST_WDMR,
62 AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
63 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
64
65 mdelay(2000);
66
67 pr_emerg("Unable to restart system\n");
68 return NOTIFY_DONE;
69 }
70
71 static struct notifier_block at91rm9200_restart_nb = {
72 .notifier_call = at91rm9200_restart,
73 .priority = 192,
74 };
75
76
77
78
79 static inline void at91_wdt_stop(void)
80 {
81 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
82 }
83
84
85
86
87 static inline void at91_wdt_start(void)
88 {
89 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
90 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
91 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
92 }
93
94
95
96
97 static inline void at91_wdt_reload(void)
98 {
99 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
100 }
101
102
103
104
105
106
107 static int at91_wdt_open(struct inode *inode, struct file *file)
108 {
109 if (test_and_set_bit(0, &at91wdt_busy))
110 return -EBUSY;
111
112 at91_wdt_start();
113 return stream_open(inode, file);
114 }
115
116
117
118
119
120
121 static int at91_wdt_close(struct inode *inode, struct file *file)
122 {
123
124 if (!nowayout)
125 at91_wdt_stop();
126
127 clear_bit(0, &at91wdt_busy);
128 return 0;
129 }
130
131
132
133
134 static int at91_wdt_settimeout(int new_time)
135 {
136
137
138
139
140
141
142 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
143 return -EINVAL;
144
145
146
147 wdt_time = new_time;
148 return 0;
149 }
150
151 static const struct watchdog_info at91_wdt_info = {
152 .identity = "at91 watchdog",
153 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
154 };
155
156
157
158
159 static long at91_wdt_ioctl(struct file *file,
160 unsigned int cmd, unsigned long arg)
161 {
162 void __user *argp = (void __user *)arg;
163 int __user *p = argp;
164 int new_value;
165
166 switch (cmd) {
167 case WDIOC_GETSUPPORT:
168 return copy_to_user(argp, &at91_wdt_info,
169 sizeof(at91_wdt_info)) ? -EFAULT : 0;
170 case WDIOC_GETSTATUS:
171 case WDIOC_GETBOOTSTATUS:
172 return put_user(0, p);
173 case WDIOC_SETOPTIONS:
174 if (get_user(new_value, p))
175 return -EFAULT;
176 if (new_value & WDIOS_DISABLECARD)
177 at91_wdt_stop();
178 if (new_value & WDIOS_ENABLECARD)
179 at91_wdt_start();
180 return 0;
181 case WDIOC_KEEPALIVE:
182 at91_wdt_reload();
183 return 0;
184 case WDIOC_SETTIMEOUT:
185 if (get_user(new_value, p))
186 return -EFAULT;
187 if (at91_wdt_settimeout(new_value))
188 return -EINVAL;
189
190 at91_wdt_start();
191
192 return put_user(wdt_time, p);
193 case WDIOC_GETTIMEOUT:
194 return put_user(wdt_time, p);
195 default:
196 return -ENOTTY;
197 }
198 }
199
200
201
202
203 static ssize_t at91_wdt_write(struct file *file, const char *data,
204 size_t len, loff_t *ppos)
205 {
206 at91_wdt_reload();
207 return len;
208 }
209
210
211
212 static const struct file_operations at91wdt_fops = {
213 .owner = THIS_MODULE,
214 .llseek = no_llseek,
215 .unlocked_ioctl = at91_wdt_ioctl,
216 .open = at91_wdt_open,
217 .release = at91_wdt_close,
218 .write = at91_wdt_write,
219 };
220
221 static struct miscdevice at91wdt_miscdev = {
222 .minor = WATCHDOG_MINOR,
223 .name = "watchdog",
224 .fops = &at91wdt_fops,
225 };
226
227 static int at91wdt_probe(struct platform_device *pdev)
228 {
229 struct device *dev = &pdev->dev;
230 struct device *parent;
231 int res;
232
233 if (at91wdt_miscdev.parent)
234 return -EBUSY;
235 at91wdt_miscdev.parent = &pdev->dev;
236
237 parent = dev->parent;
238 if (!parent) {
239 dev_err(dev, "no parent\n");
240 return -ENODEV;
241 }
242
243 regmap_st = syscon_node_to_regmap(parent->of_node);
244 if (IS_ERR(regmap_st))
245 return -ENODEV;
246
247 res = misc_register(&at91wdt_miscdev);
248 if (res)
249 return res;
250
251 res = register_restart_handler(&at91rm9200_restart_nb);
252 if (res)
253 dev_warn(dev, "failed to register restart handler\n");
254
255 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
256 wdt_time, nowayout ? ", nowayout" : "");
257 return 0;
258 }
259
260 static int at91wdt_remove(struct platform_device *pdev)
261 {
262 struct device *dev = &pdev->dev;
263 int res;
264
265 res = unregister_restart_handler(&at91rm9200_restart_nb);
266 if (res)
267 dev_warn(dev, "failed to unregister restart handler\n");
268
269 misc_deregister(&at91wdt_miscdev);
270 at91wdt_miscdev.parent = NULL;
271
272 return res;
273 }
274
275 static void at91wdt_shutdown(struct platform_device *pdev)
276 {
277 at91_wdt_stop();
278 }
279
280 #ifdef CONFIG_PM
281
282 static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
283 {
284 at91_wdt_stop();
285 return 0;
286 }
287
288 static int at91wdt_resume(struct platform_device *pdev)
289 {
290 if (at91wdt_busy)
291 at91_wdt_start();
292 return 0;
293 }
294
295 #else
296 #define at91wdt_suspend NULL
297 #define at91wdt_resume NULL
298 #endif
299
300 static const struct of_device_id at91_wdt_dt_ids[] = {
301 { .compatible = "atmel,at91rm9200-wdt" },
302 { }
303 };
304 MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
305
306 static struct platform_driver at91wdt_driver = {
307 .probe = at91wdt_probe,
308 .remove = at91wdt_remove,
309 .shutdown = at91wdt_shutdown,
310 .suspend = at91wdt_suspend,
311 .resume = at91wdt_resume,
312 .driver = {
313 .name = "atmel_st_watchdog",
314 .of_match_table = at91_wdt_dt_ids,
315 },
316 };
317
318 static int __init at91_wdt_init(void)
319 {
320
321
322 if (at91_wdt_settimeout(wdt_time)) {
323 at91_wdt_settimeout(WDT_DEFAULT_TIME);
324 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
325 wdt_time);
326 }
327
328 return platform_driver_register(&at91wdt_driver);
329 }
330
331 static void __exit at91_wdt_exit(void)
332 {
333 platform_driver_unregister(&at91wdt_driver);
334 }
335
336 module_init(at91_wdt_init);
337 module_exit(at91_wdt_exit);
338
339 MODULE_AUTHOR("Andrew Victor");
340 MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
341 MODULE_LICENSE("GPL");
342 MODULE_ALIAS("platform:atmel_st_watchdog");