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11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/bitops.h>
15#include <linux/delay.h>
16#include <linux/errno.h>
17#include <linux/fs.h>
18#include <linux/init.h>
19#include <linux/io.h>
20#include <linux/kernel.h>
21#include <linux/mfd/syscon.h>
22#include <linux/mfd/syscon/atmel-st.h>
23#include <linux/miscdevice.h>
24#include <linux/module.h>
25#include <linux/moduleparam.h>
26#include <linux/platform_device.h>
27#include <linux/reboot.h>
28#include <linux/regmap.h>
29#include <linux/types.h>
30#include <linux/watchdog.h>
31#include <linux/uaccess.h>
32#include <linux/of.h>
33#include <linux/of_device.h>
34
35#define WDT_DEFAULT_TIME 5
36#define WDT_MAX_TIME 256
37
38static int wdt_time = WDT_DEFAULT_TIME;
39static bool nowayout = WATCHDOG_NOWAYOUT;
40static struct regmap *regmap_st;
41
42module_param(wdt_time, int, 0);
43MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
44 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
45
46#ifdef CONFIG_WATCHDOG_NOWAYOUT
47module_param(nowayout, bool, 0);
48MODULE_PARM_DESC(nowayout,
49 "Watchdog cannot be stopped once started (default="
50 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
51#endif
52
53
54static unsigned long at91wdt_busy;
55
56
57
58static int at91rm9200_restart(struct notifier_block *this,
59 unsigned long mode, void *cmd)
60{
61
62
63
64 regmap_write(regmap_st, AT91_ST_WDMR,
65 AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
66 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
67
68 mdelay(2000);
69
70 pr_emerg("Unable to restart system\n");
71 return NOTIFY_DONE;
72}
73
74static struct notifier_block at91rm9200_restart_nb = {
75 .notifier_call = at91rm9200_restart,
76 .priority = 192,
77};
78
79
80
81
82static inline void at91_wdt_stop(void)
83{
84 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
85}
86
87
88
89
90static inline void at91_wdt_start(void)
91{
92 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
93 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
94 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
95}
96
97
98
99
100static inline void at91_wdt_reload(void)
101{
102 regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
103}
104
105
106
107
108
109
110static int at91_wdt_open(struct inode *inode, struct file *file)
111{
112 if (test_and_set_bit(0, &at91wdt_busy))
113 return -EBUSY;
114
115 at91_wdt_start();
116 return nonseekable_open(inode, file);
117}
118
119
120
121
122
123
124static int at91_wdt_close(struct inode *inode, struct file *file)
125{
126
127 if (!nowayout)
128 at91_wdt_stop();
129
130 clear_bit(0, &at91wdt_busy);
131 return 0;
132}
133
134
135
136
137static int at91_wdt_settimeout(int new_time)
138{
139
140
141
142
143
144
145 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
146 return -EINVAL;
147
148
149
150 wdt_time = new_time;
151 return 0;
152}
153
154static const struct watchdog_info at91_wdt_info = {
155 .identity = "at91 watchdog",
156 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
157};
158
159
160
161
162static long at91_wdt_ioctl(struct file *file,
163 unsigned int cmd, unsigned long arg)
164{
165 void __user *argp = (void __user *)arg;
166 int __user *p = argp;
167 int new_value;
168
169 switch (cmd) {
170 case WDIOC_GETSUPPORT:
171 return copy_to_user(argp, &at91_wdt_info,
172 sizeof(at91_wdt_info)) ? -EFAULT : 0;
173 case WDIOC_GETSTATUS:
174 case WDIOC_GETBOOTSTATUS:
175 return put_user(0, p);
176 case WDIOC_SETOPTIONS:
177 if (get_user(new_value, p))
178 return -EFAULT;
179 if (new_value & WDIOS_DISABLECARD)
180 at91_wdt_stop();
181 if (new_value & WDIOS_ENABLECARD)
182 at91_wdt_start();
183 return 0;
184 case WDIOC_KEEPALIVE:
185 at91_wdt_reload();
186 return 0;
187 case WDIOC_SETTIMEOUT:
188 if (get_user(new_value, p))
189 return -EFAULT;
190 if (at91_wdt_settimeout(new_value))
191 return -EINVAL;
192
193 at91_wdt_start();
194
195 return put_user(wdt_time, p);
196 case WDIOC_GETTIMEOUT:
197 return put_user(wdt_time, p);
198 default:
199 return -ENOTTY;
200 }
201}
202
203
204
205
206static ssize_t at91_wdt_write(struct file *file, const char *data,
207 size_t len, loff_t *ppos)
208{
209 at91_wdt_reload();
210 return len;
211}
212
213
214
215static const struct file_operations at91wdt_fops = {
216 .owner = THIS_MODULE,
217 .llseek = no_llseek,
218 .unlocked_ioctl = at91_wdt_ioctl,
219 .open = at91_wdt_open,
220 .release = at91_wdt_close,
221 .write = at91_wdt_write,
222};
223
224static struct miscdevice at91wdt_miscdev = {
225 .minor = WATCHDOG_MINOR,
226 .name = "watchdog",
227 .fops = &at91wdt_fops,
228};
229
230static int at91wdt_probe(struct platform_device *pdev)
231{
232 struct device *dev = &pdev->dev;
233 struct device *parent;
234 int res;
235
236 if (at91wdt_miscdev.parent)
237 return -EBUSY;
238 at91wdt_miscdev.parent = &pdev->dev;
239
240 parent = dev->parent;
241 if (!parent) {
242 dev_err(dev, "no parent\n");
243 return -ENODEV;
244 }
245
246 regmap_st = syscon_node_to_regmap(parent->of_node);
247 if (!regmap_st)
248 return -ENODEV;
249
250 res = misc_register(&at91wdt_miscdev);
251 if (res)
252 return res;
253
254 res = register_restart_handler(&at91rm9200_restart_nb);
255 if (res)
256 dev_warn(dev, "failed to register restart handler\n");
257
258 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
259 wdt_time, nowayout ? ", nowayout" : "");
260 return 0;
261}
262
263static int at91wdt_remove(struct platform_device *pdev)
264{
265 struct device *dev = &pdev->dev;
266 int res;
267
268 res = unregister_restart_handler(&at91rm9200_restart_nb);
269 if (res)
270 dev_warn(dev, "failed to unregister restart handler\n");
271
272 res = misc_deregister(&at91wdt_miscdev);
273 if (!res)
274 at91wdt_miscdev.parent = NULL;
275
276 return res;
277}
278
279static void at91wdt_shutdown(struct platform_device *pdev)
280{
281 at91_wdt_stop();
282}
283
284#ifdef CONFIG_PM
285
286static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
287{
288 at91_wdt_stop();
289 return 0;
290}
291
292static int at91wdt_resume(struct platform_device *pdev)
293{
294 if (at91wdt_busy)
295 at91_wdt_start();
296 return 0;
297}
298
299#else
300#define at91wdt_suspend NULL
301#define at91wdt_resume NULL
302#endif
303
304static const struct of_device_id at91_wdt_dt_ids[] = {
305 { .compatible = "atmel,at91rm9200-wdt" },
306 { }
307};
308MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
309
310static struct platform_driver at91wdt_driver = {
311 .probe = at91wdt_probe,
312 .remove = at91wdt_remove,
313 .shutdown = at91wdt_shutdown,
314 .suspend = at91wdt_suspend,
315 .resume = at91wdt_resume,
316 .driver = {
317 .name = "atmel_st_watchdog",
318 .of_match_table = at91_wdt_dt_ids,
319 },
320};
321
322static int __init at91_wdt_init(void)
323{
324
325
326 if (at91_wdt_settimeout(wdt_time)) {
327 at91_wdt_settimeout(WDT_DEFAULT_TIME);
328 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
329 wdt_time);
330 }
331
332 return platform_driver_register(&at91wdt_driver);
333}
334
335static void __exit at91_wdt_exit(void)
336{
337 platform_driver_unregister(&at91wdt_driver);
338}
339
340module_init(at91_wdt_init);
341module_exit(at91_wdt_exit);
342
343MODULE_AUTHOR("Andrew Victor");
344MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
345MODULE_LICENSE("GPL");
346MODULE_ALIAS("platform:atmel_st_watchdog");
347
