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18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/errno.h>
21#include <linux/fs.h>
22#include <linux/init.h>
23#include <linux/io.h>
24#include <linux/kernel.h>
25#include <linux/miscdevice.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/platform_device.h>
29#include <linux/types.h>
30#include <linux/watchdog.h>
31#include <linux/jiffies.h>
32#include <linux/timer.h>
33#include <linux/bitops.h>
34#include <linux/uaccess.h>
35#include <linux/of.h>
36
37#include "at91sam9_wdt.h"
38
39#define DRV_NAME "AT91SAM9 Watchdog"
40
41#define wdt_read(field) \
42 __raw_readl(at91wdt_private.base + field)
43#define wdt_write(field, val) \
44 __raw_writel((val), at91wdt_private.base + field)
45
46
47
48
49
50#define ms_to_ticks(t) (((t << 8) / 1000) - 1)
51#define ticks_to_ms(t) (((t + 1) * 1000) >> 8)
52
53
54#define WDT_HW_TIMEOUT 2
55
56
57#define WDT_TIMEOUT (HZ/2)
58
59
60#define WDT_HEARTBEAT 15
61static int heartbeat = WDT_HEARTBEAT;
62module_param(heartbeat, int, 0);
63MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
64 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
65
66static bool nowayout = WATCHDOG_NOWAYOUT;
67module_param(nowayout, bool, 0);
68MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
69 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70
71static void at91_ping(unsigned long data);
72
73static struct {
74 void __iomem *base;
75 unsigned long next_heartbeat;
76 unsigned long open;
77 char expect_close;
78 struct timer_list timer;
79} at91wdt_private;
80
81
82
83
84
85
86
87static inline void at91_wdt_reset(void)
88{
89 wdt_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
90}
91
92
93
94
95static void at91_ping(unsigned long data)
96{
97 if (time_before(jiffies, at91wdt_private.next_heartbeat) ||
98 (!nowayout && !at91wdt_private.open)) {
99 at91_wdt_reset();
100 mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT);
101 } else
102 pr_crit("I will reset your machine !\n");
103}
104
105
106
107
108static int at91_wdt_open(struct inode *inode, struct file *file)
109{
110 if (test_and_set_bit(0, &at91wdt_private.open))
111 return -EBUSY;
112
113 at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ;
114 mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT);
115
116 return nonseekable_open(inode, file);
117}
118
119
120
121
122static int at91_wdt_close(struct inode *inode, struct file *file)
123{
124 clear_bit(0, &at91wdt_private.open);
125
126
127 if (!at91wdt_private.expect_close)
128 del_timer(&at91wdt_private.timer);
129
130 at91wdt_private.expect_close = 0;
131 return 0;
132}
133
134
135
136
137
138static int at91_wdt_settimeout(unsigned int timeout)
139{
140 unsigned int reg;
141 unsigned int mr;
142
143
144 mr = wdt_read(AT91_WDT_MR);
145 if (mr & AT91_WDT_WDDIS) {
146 pr_err("sorry, watchdog is disabled\n");
147 return -EIO;
148 }
149
150
151
152
153
154
155
156 reg = AT91_WDT_WDRSTEN
157
158 | AT91_WDT_WDDBGHLT
159 | AT91_WDT_WDD
160 | (timeout & AT91_WDT_WDV);
161 wdt_write(AT91_WDT_MR, reg);
162
163 return 0;
164}
165
166static const struct watchdog_info at91_wdt_info = {
167 .identity = DRV_NAME,
168 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
169 WDIOF_MAGICCLOSE,
170};
171
172
173
174
175static long at91_wdt_ioctl(struct file *file,
176 unsigned int cmd, unsigned long arg)
177{
178 void __user *argp = (void __user *)arg;
179 int __user *p = argp;
180 int new_value;
181
182 switch (cmd) {
183 case WDIOC_GETSUPPORT:
184 return copy_to_user(argp, &at91_wdt_info,
185 sizeof(at91_wdt_info)) ? -EFAULT : 0;
186
187 case WDIOC_GETSTATUS:
188 case WDIOC_GETBOOTSTATUS:
189 return put_user(0, p);
190
191 case WDIOC_KEEPALIVE:
192 at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ;
193 return 0;
194
195 case WDIOC_SETTIMEOUT:
196 if (get_user(new_value, p))
197 return -EFAULT;
198
199 heartbeat = new_value;
200 at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ;
201
202 return put_user(new_value, p);
203
204 case WDIOC_GETTIMEOUT:
205 return put_user(heartbeat, p);
206 }
207 return -ENOTTY;
208}
209
210
211
212
213static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len,
214 loff_t *ppos)
215{
216 if (!len)
217 return 0;
218
219
220 if (!nowayout) {
221 size_t i;
222
223 at91wdt_private.expect_close = 0;
224
225 for (i = 0; i < len; i++) {
226 char c;
227 if (get_user(c, data + i))
228 return -EFAULT;
229 if (c == 'V') {
230 at91wdt_private.expect_close = 42;
231 break;
232 }
233 }
234 }
235
236 at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ;
237
238 return len;
239}
240
241
242
243static const struct file_operations at91wdt_fops = {
244 .owner = THIS_MODULE,
245 .llseek = no_llseek,
246 .unlocked_ioctl = at91_wdt_ioctl,
247 .open = at91_wdt_open,
248 .release = at91_wdt_close,
249 .write = at91_wdt_write,
250};
251
252static struct miscdevice at91wdt_miscdev = {
253 .minor = WATCHDOG_MINOR,
254 .name = "watchdog",
255 .fops = &at91wdt_fops,
256};
257
258static int __init at91wdt_probe(struct platform_device *pdev)
259{
260 struct resource *r;
261 int res;
262
263 if (at91wdt_miscdev.parent)
264 return -EBUSY;
265 at91wdt_miscdev.parent = &pdev->dev;
266
267 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
268 if (!r)
269 return -ENODEV;
270 at91wdt_private.base = ioremap(r->start, resource_size(r));
271 if (!at91wdt_private.base) {
272 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
273 return -ENOMEM;
274 }
275
276
277 res = at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000));
278 if (res)
279 return res;
280
281 res = misc_register(&at91wdt_miscdev);
282 if (res)
283 return res;
284
285 at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ;
286 setup_timer(&at91wdt_private.timer, at91_ping, 0);
287 mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT);
288
289 pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
290 heartbeat, nowayout);
291
292 return 0;
293}
294
295static int __exit at91wdt_remove(struct platform_device *pdev)
296{
297 int res;
298
299 res = misc_deregister(&at91wdt_miscdev);
300 if (!res)
301 at91wdt_miscdev.parent = NULL;
302
303 return res;
304}
305
306#if defined(CONFIG_OF)
307static const struct of_device_id at91_wdt_dt_ids[] __initconst = {
308 { .compatible = "atmel,at91sam9260-wdt" },
309 { }
310};
311
312MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
313#endif
314
315static struct platform_driver at91wdt_driver = {
316 .remove = __exit_p(at91wdt_remove),
317 .driver = {
318 .name = "at91_wdt",
319 .owner = THIS_MODULE,
320 .of_match_table = of_match_ptr(at91_wdt_dt_ids),
321 },
322};
323
324static int __init at91sam_wdt_init(void)
325{
326 return platform_driver_probe(&at91wdt_driver, at91wdt_probe);
327}
328
329static void __exit at91sam_wdt_exit(void)
330{
331 platform_driver_unregister(&at91wdt_driver);
332}
333
334module_init(at91sam_wdt_init);
335module_exit(at91sam_wdt_exit);
336
337MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>");
338MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
339MODULE_LICENSE("GPL");
340MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
341