virtio_blk: use a wrapper function to access io context information of IO requests
[linux-3.10.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@redhat.com>, All Rights Reserved.
8  *                              http://www.redhat.com
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
34 #include <asm/hardware/arm_twd.h>
35
36 struct 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
45 static struct platform_device *mpcore_wdt_dev;
46 extern unsigned int mpcore_timer_rate;
47
48 #define TIMER_MARGIN    60
49 static int mpcore_margin = TIMER_MARGIN;
50 module_param(mpcore_margin, int, 0);
51 MODULE_PARM_DESC(mpcore_margin,
52         "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
53                                 __MODULE_STRING(TIMER_MARGIN) ")");
54
55 static int nowayout = WATCHDOG_NOWAYOUT;
56 module_param(nowayout, int, 0);
57 MODULE_PARM_DESC(nowayout,
58         "Watchdog cannot be stopped once started (default="
59                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
60
61 #define ONLY_TESTING    0
62 static int mpcore_noboot = ONLY_TESTING;
63 module_param(mpcore_noboot, int, 0);
64 MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, set to 1 to ignore reboots, 0 to reboot (default=" __MODULE_STRING(ONLY_TESTING) ")");
65
66 /*
67  *      This is the interrupt handler.  Note that we only use this
68  *      in testing mode, so don't actually do a reboot here.
69  */
70 static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
71 {
72         struct mpcore_wdt *wdt = arg;
73
74         /* Check it really was our interrupt */
75         if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
76                 dev_printk(KERN_CRIT, wdt->dev,
77                                         "Triggered - Reboot ignored.\n");
78                 /* Clear the interrupt on the watchdog */
79                 writel(1, wdt->base + TWD_WDOG_INTSTAT);
80                 return IRQ_HANDLED;
81         }
82         return IRQ_NONE;
83 }
84
85 /*
86  *      mpcore_wdt_keepalive - reload the timer
87  *
88  *      Note that the spec says a DIFFERENT value must be written to the reload
89  *      register each time.  The "perturb" variable deals with this by adding 1
90  *      to the count every other time the function is called.
91  */
92 static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
93 {
94         unsigned int count;
95
96         /* Assume prescale is set to 256 */
97         count = (mpcore_timer_rate / 256) * mpcore_margin;
98
99         /* Reload the counter */
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
106 static 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
115 static 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         /* This loads the count register but does NOT start the count yet */
121         mpcore_wdt_keepalive(wdt);
122
123         if (mpcore_noboot) {
124                 /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
125                 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
126         } else {
127                 /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
128                 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
129         }
130         spin_unlock(&wdt_lock);
131 }
132
133 static 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  *      /dev/watchdog handling
144  */
145 static 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          *      Activate timer
159          */
160         mpcore_wdt_start(wdt);
161
162         return nonseekable_open(inode, file);
163 }
164
165 static int mpcore_wdt_release(struct inode *inode, struct file *file)
166 {
167         struct mpcore_wdt *wdt = file->private_data;
168
169         /*
170          *      Shut off the timer.
171          *      Lock it in if it's a module and we set nowayout
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
185 static 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          *      Refresh the timer.
192          */
193         if (len) {
194                 if (!nowayout) {
195                         size_t i;
196
197                         /* In case it was set long ago */
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
214 static struct watchdog_info ident = {
215         .options                = WDIOF_SETTIMEOUT |
216                                   WDIOF_KEEPALIVEPING |
217                                   WDIOF_MAGICCLOSE,
218         .identity               = "MPcore Watchdog",
219 };
220
221 static 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                 /* Fall */
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  *      System shutdown handler.  Turn off the watchdog if we're
295  *      restarting or halting the system.
296  */
297 static 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  *      Kernel Interfaces
307  */
308 static 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
317 static struct miscdevice mpcore_wdt_miscdev = {
318         .minor          = WATCHDOG_MINOR,
319         .name           = "watchdog",
320         .fops           = &mpcore_wdt_fops,
321 };
322
323 static int __devinit mpcore_wdt_probe(struct platform_device *dev)
324 {
325         struct mpcore_wdt *wdt;
326         struct resource *res;
327         int ret;
328
329         /* We only accept one device, and it must have an id of -1 */
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
380 err_irq:
381         misc_deregister(&mpcore_wdt_miscdev);
382 err_misc:
383         iounmap(wdt->base);
384 err_free:
385         kfree(wdt);
386 err_out:
387         return ret;
388 }
389
390 static 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 /* work with hotplug and coldplug */
407 MODULE_ALIAS("platform:mpcore_wdt");
408
409 static 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
419 static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
420
421 static int __init mpcore_wdt_init(void)
422 {
423         /*
424          * Check that the margin value is within it's range;
425          * if not reset to the default
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
438 static void __exit mpcore_wdt_exit(void)
439 {
440         platform_driver_unregister(&mpcore_wdt_driver);
441 }
442
443 module_init(mpcore_wdt_init);
444 module_exit(mpcore_wdt_exit);
445
446 MODULE_AUTHOR("ARM Limited");
447 MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
448 MODULE_LICENSE("GPL");
449 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);