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22#include <linux/module.h>
23#include <linux/moduleparam.h>
24#include <linux/types.h>
25#include <linux/miscdevice.h>
26#include <linux/watchdog.h>
27#include <linux/fs.h>
28#include <linux/reboot.h>
29#include <linux/init.h>
30#include <linux/interrupt.h>
31#include <linux/platform_device.h>
32
33#include <asm/hardware/arm_twd.h>
34#include <asm/uaccess.h>
35
36struct mpcore_wdt {
37 unsigned long timer_alive;
38 struct device *dev;
39 void __iomem *base;
40 int irq;
41 unsigned int perturb;
42 char expect_close;
43};
44
45static struct platform_device *mpcore_wdt_dev;
46
47extern unsigned int mpcore_timer_rate;
48
49#define TIMER_MARGIN 60
50static int mpcore_margin = TIMER_MARGIN;
51module_param(mpcore_margin, int, 0);
52MODULE_PARM_DESC(mpcore_margin, "MPcore timer margin in seconds. (0<mpcore_margin<65536, default=" __MODULE_STRING(TIMER_MARGIN) ")");
53
54static int nowayout = WATCHDOG_NOWAYOUT;
55module_param(nowayout, int, 0);
56MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
57
58#define ONLY_TESTING 0
59static int mpcore_noboot = ONLY_TESTING;
60module_param(mpcore_noboot, int, 0);
61MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, set to 1 to ignore reboots, 0 to reboot (default=" __MODULE_STRING(ONLY_TESTING) ")");
62
63
64
65
66
67static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
68{
69 struct mpcore_wdt *wdt = arg;
70
71
72 if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
73 dev_printk(KERN_CRIT, wdt->dev, "Triggered - Reboot ignored.\n");
74
75
76 writel(1, wdt->base + TWD_WDOG_INTSTAT);
77
78 return IRQ_HANDLED;
79 }
80
81 return IRQ_NONE;
82}
83
84
85
86
87
88
89
90
91static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
92{
93 unsigned int count;
94
95
96 count = (mpcore_timer_rate / 256) * mpcore_margin;
97
98
99 writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
100
101 wdt->perturb = wdt->perturb ? 0 : 1;
102}
103
104static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
105{
106 writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
107 writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
108 writel(0x0, wdt->base + TWD_WDOG_CONTROL);
109}
110
111static void mpcore_wdt_start(struct mpcore_wdt *wdt)
112{
113 dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
114
115
116 mpcore_wdt_keepalive(wdt);
117
118 if (mpcore_noboot) {
119
120 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
121 } else {
122
123 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
124 }
125}
126
127static int mpcore_wdt_set_heartbeat(int t)
128{
129 if (t < 0x0001 || t > 0xFFFF)
130 return -EINVAL;
131
132 mpcore_margin = t;
133 return 0;
134}
135
136
137
138
139static int mpcore_wdt_open(struct inode *inode, struct file *file)
140{
141 struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
142
143 if (test_and_set_bit(0, &wdt->timer_alive))
144 return -EBUSY;
145
146 if (nowayout)
147 __module_get(THIS_MODULE);
148
149 file->private_data = wdt;
150
151
152
153
154 mpcore_wdt_start(wdt);
155
156 return nonseekable_open(inode, file);
157}
158
159static int mpcore_wdt_release(struct inode *inode, struct file *file)
160{
161 struct mpcore_wdt *wdt = file->private_data;
162
163
164
165
166
167 if (wdt->expect_close == 42) {
168 mpcore_wdt_stop(wdt);
169 } else {
170 dev_printk(KERN_CRIT, wdt->dev, "unexpected close, not stopping watchdog!\n");
171 mpcore_wdt_keepalive(wdt);
172 }
173 clear_bit(0, &wdt->timer_alive);
174 wdt->expect_close = 0;
175 return 0;
176}
177
178static ssize_t mpcore_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
179{
180 struct mpcore_wdt *wdt = file->private_data;
181
182
183
184
185 if (len) {
186 if (!nowayout) {
187 size_t i;
188
189
190 wdt->expect_close = 0;
191
192 for (i = 0; i != len; i++) {
193 char c;
194
195 if (get_user(c, data + i))
196 return -EFAULT;
197 if (c == 'V')
198 wdt->expect_close = 42;
199 }
200 }
201 mpcore_wdt_keepalive(wdt);
202 }
203 return len;
204}
205
206static struct watchdog_info ident = {
207 .options = WDIOF_SETTIMEOUT |
208 WDIOF_KEEPALIVEPING |
209 WDIOF_MAGICCLOSE,
210 .identity = "MPcore Watchdog",
211};
212
213static int mpcore_wdt_ioctl(struct inode *inode, struct file *file,
214 unsigned int cmd, unsigned long arg)
215{
216 struct mpcore_wdt *wdt = file->private_data;
217 int ret;
218 union {
219 struct watchdog_info ident;
220 int i;
221 } uarg;
222
223 if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
224 return -ENOTTY;
225
226 if (_IOC_DIR(cmd) & _IOC_WRITE) {
227 ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
228 if (ret)
229 return -EFAULT;
230 }
231
232 switch (cmd) {
233 case WDIOC_GETSUPPORT:
234 uarg.ident = ident;
235 ret = 0;
236 break;
237
238 case WDIOC_SETOPTIONS:
239 ret = -EINVAL;
240 if (uarg.i & WDIOS_DISABLECARD) {
241 mpcore_wdt_stop(wdt);
242 ret = 0;
243 }
244 if (uarg.i & WDIOS_ENABLECARD) {
245 mpcore_wdt_start(wdt);
246 ret = 0;
247 }
248 break;
249
250 case WDIOC_GETSTATUS:
251 case WDIOC_GETBOOTSTATUS:
252 uarg.i = 0;
253 ret = 0;
254 break;
255
256 case WDIOC_KEEPALIVE:
257 mpcore_wdt_keepalive(wdt);
258 ret = 0;
259 break;
260
261 case WDIOC_SETTIMEOUT:
262 ret = mpcore_wdt_set_heartbeat(uarg.i);
263 if (ret)
264 break;
265
266 mpcore_wdt_keepalive(wdt);
267
268 case WDIOC_GETTIMEOUT:
269 uarg.i = mpcore_margin;
270 ret = 0;
271 break;
272
273 default:
274 return -ENOTTY;
275 }
276
277 if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
278 ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
279 if (ret)
280 ret = -EFAULT;
281 }
282 return ret;
283}
284
285
286
287
288
289static void mpcore_wdt_shutdown(struct platform_device *dev)
290{
291 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
292
293 if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
294 mpcore_wdt_stop(wdt);
295}
296
297
298
299
300static const struct file_operations mpcore_wdt_fops = {
301 .owner = THIS_MODULE,
302 .llseek = no_llseek,
303 .write = mpcore_wdt_write,
304 .ioctl = mpcore_wdt_ioctl,
305 .open = mpcore_wdt_open,
306 .release = mpcore_wdt_release,
307};
308
309static struct miscdevice mpcore_wdt_miscdev = {
310 .minor = WATCHDOG_MINOR,
311 .name = "watchdog",
312 .fops = &mpcore_wdt_fops,
313};
314
315static int __devinit mpcore_wdt_probe(struct platform_device *dev)
316{
317 struct mpcore_wdt *wdt;
318 struct resource *res;
319 int ret;
320
321
322 if (dev->id != -1)
323 return -ENODEV;
324
325 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
326 if (!res) {
327 ret = -ENODEV;
328 goto err_out;
329 }
330
331 wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
332 if (!wdt) {
333 ret = -ENOMEM;
334 goto err_out;
335 }
336
337 wdt->dev = &dev->dev;
338 wdt->irq = platform_get_irq(dev, 0);
339 if (wdt->irq < 0) {
340 ret = -ENXIO;
341 goto err_free;
342 }
343 wdt->base = ioremap(res->start, res->end - res->start + 1);
344 if (!wdt->base) {
345 ret = -ENOMEM;
346 goto err_free;
347 }
348
349 mpcore_wdt_miscdev.parent = &dev->dev;
350 ret = misc_register(&mpcore_wdt_miscdev);
351 if (ret) {
352 dev_printk(KERN_ERR, _dev, "cannot register miscdev on minor=%d (err=%d)\n",
353 WATCHDOG_MINOR, ret);
354 goto err_misc;
355 }
356
357 ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED, "mpcore_wdt", wdt);
358 if (ret) {
359 dev_printk(KERN_ERR, _dev, "cannot register IRQ%d for watchdog\n", wdt->irq);
360 goto err_irq;
361 }
362
363 mpcore_wdt_stop(wdt);
364 platform_set_drvdata(&dev->dev, wdt);
365 mpcore_wdt_dev = dev;
366
367 return 0;
368
369 err_irq:
370 misc_deregister(&mpcore_wdt_miscdev);
371 err_misc:
372 iounmap(wdt->base);
373 err_free:
374 kfree(wdt);
375 err_out:
376 return ret;
377}
378
379static int __devexit mpcore_wdt_remove(struct platform_device *dev)
380{
381 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
382
383 platform_set_drvdata(dev, NULL);
384
385 misc_deregister(&mpcore_wdt_miscdev);
386
387 mpcore_wdt_dev = NULL;
388
389 free_irq(wdt->irq, wdt);
390 iounmap(wdt->base);
391 kfree(wdt);
392 return 0;
393}
394
395static struct platform_driver mpcore_wdt_driver = {
396 .probe = mpcore_wdt_probe,
397 .remove = __devexit_p(mpcore_wdt_remove),
398 .shutdown = mpcore_wdt_shutdown,
399 .driver = {
400 .owner = THIS_MODULE,
401 .name = "mpcore_wdt",
402 },
403};
404
405static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
406
407static int __init mpcore_wdt_init(void)
408{
409
410
411
412
413 if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
414 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
415 printk(KERN_INFO "mpcore_margin value must be 0<mpcore_margin<65536, using %d\n",
416 TIMER_MARGIN);
417 }
418
419 printk(banner, mpcore_noboot, mpcore_margin, nowayout);
420
421 return platform_driver_register(&mpcore_wdt_driver);
422}
423
424static void __exit mpcore_wdt_exit(void)
425{
426 platform_driver_unregister(&mpcore_wdt_driver);
427}
428
429module_init(mpcore_wdt_init);
430module_exit(mpcore_wdt_exit);
431
432MODULE_AUTHOR("ARM Limited");
433MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
434MODULE_LICENSE("GPL");
435MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
436
