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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#include <linux/uaccess.h>
33
34#include <asm/hardware/arm_twd.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;
46extern unsigned int mpcore_timer_rate;
47
48#define TIMER_MARGIN 60
49static int mpcore_margin = TIMER_MARGIN;
50module_param(mpcore_margin, int, 0);
51MODULE_PARM_DESC(mpcore_margin,
52 "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
53 __MODULE_STRING(TIMER_MARGIN) ")");
54
55static int nowayout = WATCHDOG_NOWAYOUT;
56module_param(nowayout, int, 0);
57MODULE_PARM_DESC(nowayout,
58 "Watchdog cannot be stopped once started (default="
59 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
60
61#define ONLY_TESTING 0
62static int mpcore_noboot = ONLY_TESTING;
63module_param(mpcore_noboot, int, 0);
64MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, set to 1 to ignore reboots, 0 to reboot (default=" __MODULE_STRING(ONLY_TESTING) ")");
65
66
67
68
69
70static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
71{
72 struct mpcore_wdt *wdt = arg;
73
74
75 if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
76 dev_printk(KERN_CRIT, wdt->dev,
77 "Triggered - Reboot ignored.\n");
78
79 writel(1, wdt->base + TWD_WDOG_INTSTAT);
80 return IRQ_HANDLED;
81 }
82 return IRQ_NONE;
83}
84
85
86
87
88
89
90
91
92static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
93{
94 unsigned int count;
95
96
97 count = (mpcore_timer_rate / 256) * mpcore_margin;
98
99
100 spin_lock(&wdt_lock);
101 writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
102 wdt->perturb = wdt->perturb ? 0 : 1;
103 spin_unlock(&wdt_lock);
104}
105
106static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
107{
108 spin_lock(&wdt_lock);
109 writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
110 writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
111 writel(0x0, wdt->base + TWD_WDOG_CONTROL);
112 spin_unlock(&wdt_lock);
113}
114
115static void mpcore_wdt_start(struct mpcore_wdt *wdt)
116{
117 dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
118
119 spin_lock(&wdt_lock);
120
121 mpcore_wdt_keepalive(wdt);
122
123 if (mpcore_noboot) {
124
125 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
126 } else {
127
128 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
129 }
130 spin_unlock(&wdt_lock);
131}
132
133static int mpcore_wdt_set_heartbeat(int t)
134{
135 if (t < 0x0001 || t > 0xFFFF)
136 return -EINVAL;
137
138 mpcore_margin = t;
139 return 0;
140}
141
142
143
144
145static int mpcore_wdt_open(struct inode *inode, struct file *file)
146{
147 struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
148
149 if (test_and_set_bit(0, &wdt->timer_alive))
150 return -EBUSY;
151
152 if (nowayout)
153 __module_get(THIS_MODULE);
154
155 file->private_data = wdt;
156
157
158
159
160 mpcore_wdt_start(wdt);
161
162 return nonseekable_open(inode, file);
163}
164
165static int mpcore_wdt_release(struct inode *inode, struct file *file)
166{
167 struct mpcore_wdt *wdt = file->private_data;
168
169
170
171
172
173 if (wdt->expect_close == 42)
174 mpcore_wdt_stop(wdt);
175 else {
176 dev_printk(KERN_CRIT, wdt->dev,
177 "unexpected close, not stopping watchdog!\n");
178 mpcore_wdt_keepalive(wdt);
179 }
180 clear_bit(0, &wdt->timer_alive);
181 wdt->expect_close = 0;
182 return 0;
183}
184
185static ssize_t mpcore_wdt_write(struct file *file, const char *data,
186 size_t len, loff_t *ppos)
187{
188 struct mpcore_wdt *wdt = file->private_data;
189
190
191
192
193 if (len) {
194 if (!nowayout) {
195 size_t i;
196
197
198 wdt->expect_close = 0;
199
200 for (i = 0; i != len; i++) {
201 char c;
202
203 if (get_user(c, data + i))
204 return -EFAULT;
205 if (c == 'V')
206 wdt->expect_close = 42;
207 }
208 }
209 mpcore_wdt_keepalive(wdt);
210 }
211 return len;
212}
213
214static struct watchdog_info ident = {
215 .options = WDIOF_SETTIMEOUT |
216 WDIOF_KEEPALIVEPING |
217 WDIOF_MAGICCLOSE,
218 .identity = "MPcore Watchdog",
219};
220
221static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
222 unsigned long arg)
223{
224 struct mpcore_wdt *wdt = file->private_data;
225 int ret;
226 union {
227 struct watchdog_info ident;
228 int i;
229 } uarg;
230
231 if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
232 return -ENOTTY;
233
234 if (_IOC_DIR(cmd) & _IOC_WRITE) {
235 ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
236 if (ret)
237 return -EFAULT;
238 }
239
240 switch (cmd) {
241 case WDIOC_GETSUPPORT:
242 uarg.ident = ident;
243 ret = 0;
244 break;
245
246 case WDIOC_GETSTATUS:
247 case WDIOC_GETBOOTSTATUS:
248 uarg.i = 0;
249 ret = 0;
250 break;
251
252 case WDIOC_SETOPTIONS:
253 ret = -EINVAL;
254 if (uarg.i & WDIOS_DISABLECARD) {
255 mpcore_wdt_stop(wdt);
256 ret = 0;
257 }
258 if (uarg.i & WDIOS_ENABLECARD) {
259 mpcore_wdt_start(wdt);
260 ret = 0;
261 }
262 break;
263
264 case WDIOC_KEEPALIVE:
265 mpcore_wdt_keepalive(wdt);
266 ret = 0;
267 break;
268
269 case WDIOC_SETTIMEOUT:
270 ret = mpcore_wdt_set_heartbeat(uarg.i);
271 if (ret)
272 break;
273
274 mpcore_wdt_keepalive(wdt);
275
276 case WDIOC_GETTIMEOUT:
277 uarg.i = mpcore_margin;
278 ret = 0;
279 break;
280
281 default:
282 return -ENOTTY;
283 }
284
285 if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
286 ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
287 if (ret)
288 ret = -EFAULT;
289 }
290 return ret;
291}
292
293
294
295
296
297static void mpcore_wdt_shutdown(struct platform_device *dev)
298{
299 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
300
301 if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
302 mpcore_wdt_stop(wdt);
303}
304
305
306
307
308static const struct file_operations mpcore_wdt_fops = {
309 .owner = THIS_MODULE,
310 .llseek = no_llseek,
311 .write = mpcore_wdt_write,
312 .unlocked_ioctl = mpcore_wdt_ioctl,
313 .open = mpcore_wdt_open,
314 .release = mpcore_wdt_release,
315};
316
317static struct miscdevice mpcore_wdt_miscdev = {
318 .minor = WATCHDOG_MINOR,
319 .name = "watchdog",
320 .fops = &mpcore_wdt_fops,
321};
322
323static int __devinit mpcore_wdt_probe(struct platform_device *dev)
324{
325 struct mpcore_wdt *wdt;
326 struct resource *res;
327 int ret;
328
329
330 if (dev->id != -1)
331 return -ENODEV;
332
333 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
334 if (!res) {
335 ret = -ENODEV;
336 goto err_out;
337 }
338
339 wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
340 if (!wdt) {
341 ret = -ENOMEM;
342 goto err_out;
343 }
344
345 wdt->dev = &dev->dev;
346 wdt->irq = platform_get_irq(dev, 0);
347 if (wdt->irq < 0) {
348 ret = -ENXIO;
349 goto err_free;
350 }
351 wdt->base = ioremap(res->start, res->end - res->start + 1);
352 if (!wdt->base) {
353 ret = -ENOMEM;
354 goto err_free;
355 }
356
357 mpcore_wdt_miscdev.parent = &dev->dev;
358 ret = misc_register(&mpcore_wdt_miscdev);
359 if (ret) {
360 dev_printk(KERN_ERR, _dev,
361 "cannot register miscdev on minor=%d (err=%d)\n",
362 WATCHDOG_MINOR, ret);
363 goto err_misc;
364 }
365
366 ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED,
367 "mpcore_wdt", wdt);
368 if (ret) {
369 dev_printk(KERN_ERR, _dev,
370 "cannot register IRQ%d for watchdog\n", wdt->irq);
371 goto err_irq;
372 }
373
374 mpcore_wdt_stop(wdt);
375 platform_set_drvdata(&dev->dev, wdt);
376 mpcore_wdt_dev = dev;
377
378 return 0;
379
380err_irq:
381 misc_deregister(&mpcore_wdt_miscdev);
382err_misc:
383 iounmap(wdt->base);
384err_free:
385 kfree(wdt);
386err_out:
387 return ret;
388}
389
390static int __devexit mpcore_wdt_remove(struct platform_device *dev)
391{
392 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
393
394 platform_set_drvdata(dev, NULL);
395
396 misc_deregister(&mpcore_wdt_miscdev);
397
398 mpcore_wdt_dev = NULL;
399
400 free_irq(wdt->irq, wdt);
401 iounmap(wdt->base);
402 kfree(wdt);
403 return 0;
404}
405
406
407MODULE_ALIAS("platform:mpcore_wdt");
408
409static struct platform_driver mpcore_wdt_driver = {
410 .probe = mpcore_wdt_probe,
411 .remove = __devexit_p(mpcore_wdt_remove),
412 .shutdown = mpcore_wdt_shutdown,
413 .driver = {
414 .owner = THIS_MODULE,
415 .name = "mpcore_wdt",
416 },
417};
418
419static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
420
421static int __init mpcore_wdt_init(void)
422{
423
424
425
426
427 if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
428 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
429 printk(KERN_INFO "mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
430 TIMER_MARGIN);
431 }
432
433 printk(banner, mpcore_noboot, mpcore_margin, nowayout);
434
435 return platform_driver_register(&mpcore_wdt_driver);
436}
437
438static void __exit mpcore_wdt_exit(void)
439{
440 platform_driver_unregister(&mpcore_wdt_driver);
441}
442
443module_init(mpcore_wdt_init);
444module_exit(mpcore_wdt_exit);
445
446MODULE_AUTHOR("ARM Limited");
447MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
448MODULE_LICENSE("GPL");
449MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
450
