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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
35static int wdt_time = WDT_DEFAULT_TIME;
36static bool nowayout = WATCHDOG_NOWAYOUT;
37static struct regmap *regmap_st;
38
39module_param(wdt_time, int, 0);
40MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
41 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
42
43#ifdef CONFIG_WATCHDOG_NOWAYOUT
44module_param(nowayout, bool, 0);
45MODULE_PARM_DESC(nowayout,
46 "Watchdog cannot be stopped once started (default="
47 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48#endif
49
50
51static unsigned long at91wdt_busy;
52
53
54
55static 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
71static struct notifier_block at91rm9200_restart_nb = {
72 .notifier_call = at91rm9200_restart,
73 .priority = 192,
74};
75
76
77
78
79static inline void at91_wdt_stop(void)
80{
81 regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
82}
83
84
85
86
87static 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
97static 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
107static 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
121static 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
134static 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
151static const struct watchdog_info at91_wdt_info = {
152 .identity = "at91 watchdog",
153 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
154};
155
156
157
158
159static 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
203static 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
212static const struct file_operations at91wdt_fops = {
213 .owner = THIS_MODULE,
214 .llseek = no_llseek,
215 .unlocked_ioctl = at91_wdt_ioctl,
216 .compat_ioctl = compat_ptr_ioctl,
217 .open = at91_wdt_open,
218 .release = at91_wdt_close,
219 .write = at91_wdt_write,
220};
221
222static struct miscdevice at91wdt_miscdev = {
223 .minor = WATCHDOG_MINOR,
224 .name = "watchdog",
225 .fops = &at91wdt_fops,
226};
227
228static int at91wdt_probe(struct platform_device *pdev)
229{
230 struct device *dev = &pdev->dev;
231 struct device *parent;
232 int res;
233
234 if (at91wdt_miscdev.parent)
235 return -EBUSY;
236 at91wdt_miscdev.parent = &pdev->dev;
237
238 parent = dev->parent;
239 if (!parent) {
240 dev_err(dev, "no parent\n");
241 return -ENODEV;
242 }
243
244 regmap_st = syscon_node_to_regmap(parent->of_node);
245 if (IS_ERR(regmap_st))
246 return -ENODEV;
247
248 res = misc_register(&at91wdt_miscdev);
249 if (res)
250 return res;
251
252 res = register_restart_handler(&at91rm9200_restart_nb);
253 if (res)
254 dev_warn(dev, "failed to register restart handler\n");
255
256 pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
257 wdt_time, nowayout ? ", nowayout" : "");
258 return 0;
259}
260
261static int at91wdt_remove(struct platform_device *pdev)
262{
263 struct device *dev = &pdev->dev;
264 int res;
265
266 res = unregister_restart_handler(&at91rm9200_restart_nb);
267 if (res)
268 dev_warn(dev, "failed to unregister restart handler\n");
269
270 misc_deregister(&at91wdt_miscdev);
271 at91wdt_miscdev.parent = NULL;
272
273 return res;
274}
275
276static void at91wdt_shutdown(struct platform_device *pdev)
277{
278 at91_wdt_stop();
279}
280
281#ifdef CONFIG_PM
282
283static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
284{
285 at91_wdt_stop();
286 return 0;
287}
288
289static int at91wdt_resume(struct platform_device *pdev)
290{
291 if (at91wdt_busy)
292 at91_wdt_start();
293 return 0;
294}
295
296#else
297#define at91wdt_suspend NULL
298#define at91wdt_resume NULL
299#endif
300
301static const struct of_device_id at91_wdt_dt_ids[] = {
302 { .compatible = "atmel,at91rm9200-wdt" },
303 { }
304};
305MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
306
307static struct platform_driver at91wdt_driver = {
308 .probe = at91wdt_probe,
309 .remove = at91wdt_remove,
310 .shutdown = at91wdt_shutdown,
311 .suspend = at91wdt_suspend,
312 .resume = at91wdt_resume,
313 .driver = {
314 .name = "atmel_st_watchdog",
315 .of_match_table = at91_wdt_dt_ids,
316 },
317};
318
319static int __init at91_wdt_init(void)
320{
321
322
323 if (at91_wdt_settimeout(wdt_time)) {
324 at91_wdt_settimeout(WDT_DEFAULT_TIME);
325 pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
326 wdt_time);
327 }
328
329 return platform_driver_register(&at91wdt_driver);
330}
331
332static void __exit at91_wdt_exit(void)
333{
334 platform_driver_unregister(&at91wdt_driver);
335}
336
337module_init(at91_wdt_init);
338module_exit(at91_wdt_exit);
339
340MODULE_AUTHOR("Andrew Victor");
341MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
342MODULE_LICENSE("GPL");
343MODULE_ALIAS("platform:atmel_st_watchdog");
344