parport_pc: show the detection of a 2 serial port ITE8874 chip
[linux-2.6.git] / drivers / watchdog / mpcore_wdt.c
1 /*
2  *      Watchdog driver for the mpcore watchdog timer
3  *
4  *      (c) Copyright 2004 ARM Limited
5  *
6  *      Based on the SoftDog driver:
7  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
8  *                                              All Rights Reserved.
9  *
10  *      This program is free software; you can redistribute it and/or
11  *      modify it under the terms of the GNU General Public License
12  *      as published by the Free Software Foundation; either version
13  *      2 of the License, or (at your option) any later version.
14  *
15  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
16  *      warranty for any of this software. This material is provided
17  *      "AS-IS" and at no charge.
18  *
19  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
20  *
21  */
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 #include <linux/slab.h>
34 #include <linux/io.h>
35
36 #include <asm/smp_twd.h>
37
38 struct mpcore_wdt {
39         unsigned long   timer_alive;
40         struct device   *dev;
41         void __iomem    *base;
42         int             irq;
43         unsigned int    perturb;
44         char            expect_close;
45 };
46
47 static struct platform_device *mpcore_wdt_dev;
48 static DEFINE_SPINLOCK(wdt_lock);
49
50 #define TIMER_MARGIN    60
51 static int mpcore_margin = TIMER_MARGIN;
52 module_param(mpcore_margin, int, 0);
53 MODULE_PARM_DESC(mpcore_margin,
54         "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
55                                 __MODULE_STRING(TIMER_MARGIN) ")");
56
57 static int nowayout = WATCHDOG_NOWAYOUT;
58 module_param(nowayout, int, 0);
59 MODULE_PARM_DESC(nowayout,
60         "Watchdog cannot be stopped once started (default="
61                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
62
63 #define ONLY_TESTING    0
64 static int mpcore_noboot = ONLY_TESTING;
65 module_param(mpcore_noboot, int, 0);
66 MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
67         "set to 1 to ignore reboots, 0 to reboot (default="
68                                         __MODULE_STRING(ONLY_TESTING) ")");
69
70 /*
71  *      This is the interrupt handler.  Note that we only use this
72  *      in testing mode, so don't actually do a reboot here.
73  */
74 static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
75 {
76         struct mpcore_wdt *wdt = arg;
77
78         /* Check it really was our interrupt */
79         if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
80                 dev_printk(KERN_CRIT, wdt->dev,
81                                         "Triggered - Reboot ignored.\n");
82                 /* Clear the interrupt on the watchdog */
83                 writel(1, wdt->base + TWD_WDOG_INTSTAT);
84                 return IRQ_HANDLED;
85         }
86         return IRQ_NONE;
87 }
88
89 /*
90  *      mpcore_wdt_keepalive - reload the timer
91  *
92  *      Note that the spec says a DIFFERENT value must be written to the reload
93  *      register each time.  The "perturb" variable deals with this by adding 1
94  *      to the count every other time the function is called.
95  */
96 static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
97 {
98         unsigned long count;
99
100         spin_lock(&wdt_lock);
101         /* Assume prescale is set to 256 */
102         count =  __raw_readl(wdt->base + TWD_WDOG_COUNTER);
103         count = (0xFFFFFFFFU - count) * (HZ / 5);
104         count = (count / 256) * mpcore_margin;
105
106         /* Reload the counter */
107         writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
108         wdt->perturb = wdt->perturb ? 0 : 1;
109         spin_unlock(&wdt_lock);
110 }
111
112 static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
113 {
114         spin_lock(&wdt_lock);
115         writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
116         writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
117         writel(0x0, wdt->base + TWD_WDOG_CONTROL);
118         spin_unlock(&wdt_lock);
119 }
120
121 static void mpcore_wdt_start(struct mpcore_wdt *wdt)
122 {
123         dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
124
125         /* This loads the count register but does NOT start the count yet */
126         mpcore_wdt_keepalive(wdt);
127
128         if (mpcore_noboot) {
129                 /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
130                 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
131         } else {
132                 /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
133                 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
134         }
135 }
136
137 static int mpcore_wdt_set_heartbeat(int t)
138 {
139         if (t < 0x0001 || t > 0xFFFF)
140                 return -EINVAL;
141
142         mpcore_margin = t;
143         return 0;
144 }
145
146 /*
147  *      /dev/watchdog handling
148  */
149 static int mpcore_wdt_open(struct inode *inode, struct file *file)
150 {
151         struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
152
153         if (test_and_set_bit(0, &wdt->timer_alive))
154                 return -EBUSY;
155
156         if (nowayout)
157                 __module_get(THIS_MODULE);
158
159         file->private_data = wdt;
160
161         /*
162          *      Activate timer
163          */
164         mpcore_wdt_start(wdt);
165
166         return nonseekable_open(inode, file);
167 }
168
169 static int mpcore_wdt_release(struct inode *inode, struct file *file)
170 {
171         struct mpcore_wdt *wdt = file->private_data;
172
173         /*
174          *      Shut off the timer.
175          *      Lock it in if it's a module and we set nowayout
176          */
177         if (wdt->expect_close == 42)
178                 mpcore_wdt_stop(wdt);
179         else {
180                 dev_printk(KERN_CRIT, wdt->dev,
181                                 "unexpected close, not stopping watchdog!\n");
182                 mpcore_wdt_keepalive(wdt);
183         }
184         clear_bit(0, &wdt->timer_alive);
185         wdt->expect_close = 0;
186         return 0;
187 }
188
189 static ssize_t mpcore_wdt_write(struct file *file, const char *data,
190                                                 size_t len, loff_t *ppos)
191 {
192         struct mpcore_wdt *wdt = file->private_data;
193
194         /*
195          *      Refresh the timer.
196          */
197         if (len) {
198                 if (!nowayout) {
199                         size_t i;
200
201                         /* In case it was set long ago */
202                         wdt->expect_close = 0;
203
204                         for (i = 0; i != len; i++) {
205                                 char c;
206
207                                 if (get_user(c, data + i))
208                                         return -EFAULT;
209                                 if (c == 'V')
210                                         wdt->expect_close = 42;
211                         }
212                 }
213                 mpcore_wdt_keepalive(wdt);
214         }
215         return len;
216 }
217
218 static const struct watchdog_info ident = {
219         .options                = WDIOF_SETTIMEOUT |
220                                   WDIOF_KEEPALIVEPING |
221                                   WDIOF_MAGICCLOSE,
222         .identity               = "MPcore Watchdog",
223 };
224
225 static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
226                                                         unsigned long arg)
227 {
228         struct mpcore_wdt *wdt = file->private_data;
229         int ret;
230         union {
231                 struct watchdog_info ident;
232                 int i;
233         } uarg;
234
235         if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
236                 return -ENOTTY;
237
238         if (_IOC_DIR(cmd) & _IOC_WRITE) {
239                 ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
240                 if (ret)
241                         return -EFAULT;
242         }
243
244         switch (cmd) {
245         case WDIOC_GETSUPPORT:
246                 uarg.ident = ident;
247                 ret = 0;
248                 break;
249
250         case WDIOC_GETSTATUS:
251         case WDIOC_GETBOOTSTATUS:
252                 uarg.i = 0;
253                 ret = 0;
254                 break;
255
256         case WDIOC_SETOPTIONS:
257                 ret = -EINVAL;
258                 if (uarg.i & WDIOS_DISABLECARD) {
259                         mpcore_wdt_stop(wdt);
260                         ret = 0;
261                 }
262                 if (uarg.i & WDIOS_ENABLECARD) {
263                         mpcore_wdt_start(wdt);
264                         ret = 0;
265                 }
266                 break;
267
268         case WDIOC_KEEPALIVE:
269                 mpcore_wdt_keepalive(wdt);
270                 ret = 0;
271                 break;
272
273         case WDIOC_SETTIMEOUT:
274                 ret = mpcore_wdt_set_heartbeat(uarg.i);
275                 if (ret)
276                         break;
277
278                 mpcore_wdt_keepalive(wdt);
279                 /* Fall */
280         case WDIOC_GETTIMEOUT:
281                 uarg.i = mpcore_margin;
282                 ret = 0;
283                 break;
284
285         default:
286                 return -ENOTTY;
287         }
288
289         if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
290                 ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
291                 if (ret)
292                         ret = -EFAULT;
293         }
294         return ret;
295 }
296
297 /*
298  *      System shutdown handler.  Turn off the watchdog if we're
299  *      restarting or halting the system.
300  */
301 static void mpcore_wdt_shutdown(struct platform_device *dev)
302 {
303         struct mpcore_wdt *wdt = platform_get_drvdata(dev);
304
305         if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
306                 mpcore_wdt_stop(wdt);
307 }
308
309 /*
310  *      Kernel Interfaces
311  */
312 static const struct file_operations mpcore_wdt_fops = {
313         .owner          = THIS_MODULE,
314         .llseek         = no_llseek,
315         .write          = mpcore_wdt_write,
316         .unlocked_ioctl = mpcore_wdt_ioctl,
317         .open           = mpcore_wdt_open,
318         .release        = mpcore_wdt_release,
319 };
320
321 static struct miscdevice mpcore_wdt_miscdev = {
322         .minor          = WATCHDOG_MINOR,
323         .name           = "watchdog",
324         .fops           = &mpcore_wdt_fops,
325 };
326
327 static int __devinit mpcore_wdt_probe(struct platform_device *dev)
328 {
329         struct mpcore_wdt *wdt;
330         struct resource *res;
331         int ret;
332
333         /* We only accept one device, and it must have an id of -1 */
334         if (dev->id != -1)
335                 return -ENODEV;
336
337         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
338         if (!res) {
339                 ret = -ENODEV;
340                 goto err_out;
341         }
342
343         wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
344         if (!wdt) {
345                 ret = -ENOMEM;
346                 goto err_out;
347         }
348
349         wdt->dev = &dev->dev;
350         wdt->irq = platform_get_irq(dev, 0);
351         if (wdt->irq < 0) {
352                 ret = -ENXIO;
353                 goto err_free;
354         }
355         wdt->base = ioremap(res->start, resource_size(res));
356         if (!wdt->base) {
357                 ret = -ENOMEM;
358                 goto err_free;
359         }
360
361         mpcore_wdt_miscdev.parent = &dev->dev;
362         ret = misc_register(&mpcore_wdt_miscdev);
363         if (ret) {
364                 dev_printk(KERN_ERR, wdt->dev,
365                         "cannot register miscdev on minor=%d (err=%d)\n",
366                                                         WATCHDOG_MINOR, ret);
367                 goto err_misc;
368         }
369
370         ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED,
371                                                         "mpcore_wdt", wdt);
372         if (ret) {
373                 dev_printk(KERN_ERR, wdt->dev,
374                         "cannot register IRQ%d for watchdog\n", wdt->irq);
375                 goto err_irq;
376         }
377
378         mpcore_wdt_stop(wdt);
379         platform_set_drvdata(dev, wdt);
380         mpcore_wdt_dev = dev;
381
382         return 0;
383
384 err_irq:
385         misc_deregister(&mpcore_wdt_miscdev);
386 err_misc:
387         iounmap(wdt->base);
388 err_free:
389         kfree(wdt);
390 err_out:
391         return ret;
392 }
393
394 static int __devexit mpcore_wdt_remove(struct platform_device *dev)
395 {
396         struct mpcore_wdt *wdt = platform_get_drvdata(dev);
397
398         platform_set_drvdata(dev, NULL);
399
400         misc_deregister(&mpcore_wdt_miscdev);
401
402         mpcore_wdt_dev = NULL;
403
404         free_irq(wdt->irq, wdt);
405         iounmap(wdt->base);
406         kfree(wdt);
407         return 0;
408 }
409
410 /* work with hotplug and coldplug */
411 MODULE_ALIAS("platform:mpcore_wdt");
412
413 static struct platform_driver mpcore_wdt_driver = {
414         .probe          = mpcore_wdt_probe,
415         .remove         = __devexit_p(mpcore_wdt_remove),
416         .shutdown       = mpcore_wdt_shutdown,
417         .driver         = {
418                 .owner  = THIS_MODULE,
419                 .name   = "mpcore_wdt",
420         },
421 };
422
423 static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. "
424                 "mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
425
426 static int __init mpcore_wdt_init(void)
427 {
428         /*
429          * Check that the margin value is within it's range;
430          * if not reset to the default
431          */
432         if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
433                 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
434                 printk(KERN_INFO "mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
435                         TIMER_MARGIN);
436         }
437
438         printk(banner, mpcore_noboot, mpcore_margin, nowayout);
439
440         return platform_driver_register(&mpcore_wdt_driver);
441 }
442
443 static void __exit mpcore_wdt_exit(void)
444 {
445         platform_driver_unregister(&mpcore_wdt_driver);
446 }
447
448 module_init(mpcore_wdt_init);
449 module_exit(mpcore_wdt_exit);
450
451 MODULE_AUTHOR("ARM Limited");
452 MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
453 MODULE_LICENSE("GPL");
454 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);