1 /*
2 * Eurotech CPU-1220/1410/1420 on board WDT driver
3 *
4 * (c) Copyright 2001 Ascensit <support@ascensit.com>
5 * (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com>
6 * (c) Copyright 2002 Rob Radez <rob@osinvestor.com>
7 *
8 * Based on wdt.c.
9 * Original copyright messages:
10 *
11 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
12 * All Rights Reserved.
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 *
19 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
20 * warranty for any of this software. This material is provided
21 * "AS-IS" and at no charge.
22 *
23 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>*
24 */
25
26 /* Changelog:
27 *
28 * 2001 - Rodolfo Giometti
29 * Initial release
30 *
31 * 2002/04/25 - Rob Radez
32 * clean up #includes
33 * clean up locking
34 * make __setup param unique
35 * proper options in watchdog_info
36 * add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls
37 * add expect_close support
38 *
39 * 2002.05.30 - Joel Becker <joel.becker@oracle.com>
40 * Added Matt Domsch's nowayout module option.
41 */
42
43 /*
44 * The eurotech CPU-1220/1410/1420's watchdog is a part
45 * of the on-board SUPER I/O device SMSC FDC 37B782.
46 */
47
48 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
49
50 #include <linux/interrupt.h>
51 #include <linux/module.h>
52 #include <linux/moduleparam.h>
53 #include <linux/types.h>
54 #include <linux/miscdevice.h>
55 #include <linux/watchdog.h>
56 #include <linux/fs.h>
57 #include <linux/ioport.h>
58 #include <linux/notifier.h>
59 #include <linux/reboot.h>
60 #include <linux/init.h>
61 #include <linux/io.h>
62 #include <linux/uaccess.h>
63
64
65 static unsigned long eurwdt_is_open;
66 static int eurwdt_timeout;
67 static char eur_expect_close;
68 static DEFINE_SPINLOCK(eurwdt_lock);
69
70 /*
71 * You must set these - there is no sane way to probe for this board.
72 */
73
74 static int io = 0x3f0;
75 static int irq = 10;
76 static char *ev = "int";
77
78 #define WDT_TIMEOUT 60 /* 1 minute */
79
80 static bool nowayout = WATCHDOG_NOWAYOUT;
81 module_param(nowayout, bool, 0);
82 MODULE_PARM_DESC(nowayout,
83 "Watchdog cannot be stopped once started (default="
84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
85
86 /*
87 * Some symbolic names
88 */
89
90 #define WDT_CTRL_REG 0x30
91 #define WDT_OUTPIN_CFG 0xe2
92 #define WDT_EVENT_INT 0x00
93 #define WDT_EVENT_REBOOT 0x08
94 #define WDT_UNIT_SEL 0xf1
95 #define WDT_UNIT_SECS 0x80
96 #define WDT_TIMEOUT_VAL 0xf2
97 #define WDT_TIMER_CFG 0xf3
98
99
100 module_param(io, int, 0);
101 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
102 module_param(irq, int, 0);
103 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
104 module_param(ev, charp, 0);
105 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
106
107
108 /*
109 * Programming support
110 */
111
eurwdt_write_reg(u8 index,u8 data)112 static inline void eurwdt_write_reg(u8 index, u8 data)
113 {
114 outb(index, io);
115 outb(data, io+1);
116 }
117
eurwdt_lock_chip(void)118 static inline void eurwdt_lock_chip(void)
119 {
120 outb(0xaa, io);
121 }
122
eurwdt_unlock_chip(void)123 static inline void eurwdt_unlock_chip(void)
124 {
125 outb(0x55, io);
126 eurwdt_write_reg(0x07, 0x08); /* set the logical device */
127 }
128
eurwdt_set_timeout(int timeout)129 static inline void eurwdt_set_timeout(int timeout)
130 {
131 eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
132 }
133
eurwdt_disable_timer(void)134 static inline void eurwdt_disable_timer(void)
135 {
136 eurwdt_set_timeout(0);
137 }
138
eurwdt_activate_timer(void)139 static void eurwdt_activate_timer(void)
140 {
141 eurwdt_disable_timer();
142 eurwdt_write_reg(WDT_CTRL_REG, 0x01); /* activate the WDT */
143 eurwdt_write_reg(WDT_OUTPIN_CFG,
144 !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
145
146 /* Setting interrupt line */
147 if (irq == 2 || irq > 15 || irq < 0) {
148 pr_err("invalid irq number\n");
149 irq = 0; /* if invalid we disable interrupt */
150 }
151 if (irq == 0)
152 pr_info("interrupt disabled\n");
153
154 eurwdt_write_reg(WDT_TIMER_CFG, irq << 4);
155
156 eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */
157 eurwdt_set_timeout(0); /* the default timeout */
158 }
159
160
161 /*
162 * Kernel methods.
163 */
164
eurwdt_interrupt(int irq,void * dev_id)165 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
166 {
167 pr_crit("timeout WDT timeout\n");
168
169 #ifdef ONLY_TESTING
170 pr_crit("Would Reboot\n");
171 #else
172 pr_crit("Initiating system reboot\n");
173 emergency_restart();
174 #endif
175 return IRQ_HANDLED;
176 }
177
178
179 /**
180 * eurwdt_ping:
181 *
182 * Reload counter one with the watchdog timeout.
183 */
184
eurwdt_ping(void)185 static void eurwdt_ping(void)
186 {
187 /* Write the watchdog default value */
188 eurwdt_set_timeout(eurwdt_timeout);
189 }
190
191 /**
192 * eurwdt_write:
193 * @file: file handle to the watchdog
194 * @buf: buffer to write (unused as data does not matter here
195 * @count: count of bytes
196 * @ppos: pointer to the position to write. No seeks allowed
197 *
198 * A write to a watchdog device is defined as a keepalive signal. Any
199 * write of data will do, as we we don't define content meaning.
200 */
201
eurwdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)202 static ssize_t eurwdt_write(struct file *file, const char __user *buf,
203 size_t count, loff_t *ppos)
204 {
205 if (count) {
206 if (!nowayout) {
207 size_t i;
208
209 eur_expect_close = 0;
210
211 for (i = 0; i != count; i++) {
212 char c;
213 if (get_user(c, buf + i))
214 return -EFAULT;
215 if (c == 'V')
216 eur_expect_close = 42;
217 }
218 }
219 spin_lock(&eurwdt_lock);
220 eurwdt_ping(); /* the default timeout */
221 spin_unlock(&eurwdt_lock);
222 }
223 return count;
224 }
225
226 /**
227 * eurwdt_ioctl:
228 * @file: file handle to the device
229 * @cmd: watchdog command
230 * @arg: argument pointer
231 *
232 * The watchdog API defines a common set of functions for all watchdogs
233 * according to their available features.
234 */
235
eurwdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)236 static long eurwdt_ioctl(struct file *file,
237 unsigned int cmd, unsigned long arg)
238 {
239 void __user *argp = (void __user *)arg;
240 int __user *p = argp;
241 static const struct watchdog_info ident = {
242 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
243 | WDIOF_MAGICCLOSE,
244 .firmware_version = 1,
245 .identity = "WDT Eurotech CPU-1220/1410",
246 };
247
248 int time;
249 int options, retval = -EINVAL;
250
251 switch (cmd) {
252 case WDIOC_GETSUPPORT:
253 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
254
255 case WDIOC_GETSTATUS:
256 case WDIOC_GETBOOTSTATUS:
257 return put_user(0, p);
258
259 case WDIOC_SETOPTIONS:
260 if (get_user(options, p))
261 return -EFAULT;
262 spin_lock(&eurwdt_lock);
263 if (options & WDIOS_DISABLECARD) {
264 eurwdt_disable_timer();
265 retval = 0;
266 }
267 if (options & WDIOS_ENABLECARD) {
268 eurwdt_activate_timer();
269 eurwdt_ping();
270 retval = 0;
271 }
272 spin_unlock(&eurwdt_lock);
273 return retval;
274
275 case WDIOC_KEEPALIVE:
276 spin_lock(&eurwdt_lock);
277 eurwdt_ping();
278 spin_unlock(&eurwdt_lock);
279 return 0;
280
281 case WDIOC_SETTIMEOUT:
282 if (copy_from_user(&time, p, sizeof(int)))
283 return -EFAULT;
284
285 /* Sanity check */
286 if (time < 0 || time > 255)
287 return -EINVAL;
288
289 spin_lock(&eurwdt_lock);
290 eurwdt_timeout = time;
291 eurwdt_set_timeout(time);
292 spin_unlock(&eurwdt_lock);
293 /* Fall */
294
295 case WDIOC_GETTIMEOUT:
296 return put_user(eurwdt_timeout, p);
297
298 default:
299 return -ENOTTY;
300 }
301 }
302
303 /**
304 * eurwdt_open:
305 * @inode: inode of device
306 * @file: file handle to device
307 *
308 * The misc device has been opened. The watchdog device is single
309 * open and on opening we load the counter.
310 */
311
eurwdt_open(struct inode * inode,struct file * file)312 static int eurwdt_open(struct inode *inode, struct file *file)
313 {
314 if (test_and_set_bit(0, &eurwdt_is_open))
315 return -EBUSY;
316 eurwdt_timeout = WDT_TIMEOUT; /* initial timeout */
317 /* Activate the WDT */
318 eurwdt_activate_timer();
319 return nonseekable_open(inode, file);
320 }
321
322 /**
323 * eurwdt_release:
324 * @inode: inode to board
325 * @file: file handle to board
326 *
327 * The watchdog has a configurable API. There is a religious dispute
328 * between people who want their watchdog to be able to shut down and
329 * those who want to be sure if the watchdog manager dies the machine
330 * reboots. In the former case we disable the counters, in the latter
331 * case you have to open it again very soon.
332 */
333
eurwdt_release(struct inode * inode,struct file * file)334 static int eurwdt_release(struct inode *inode, struct file *file)
335 {
336 if (eur_expect_close == 42)
337 eurwdt_disable_timer();
338 else {
339 pr_crit("Unexpected close, not stopping watchdog!\n");
340 eurwdt_ping();
341 }
342 clear_bit(0, &eurwdt_is_open);
343 eur_expect_close = 0;
344 return 0;
345 }
346
347 /**
348 * eurwdt_notify_sys:
349 * @this: our notifier block
350 * @code: the event being reported
351 * @unused: unused
352 *
353 * Our notifier is called on system shutdowns. We want to turn the card
354 * off at reboot otherwise the machine will reboot again during memory
355 * test or worse yet during the following fsck. This would suck, in fact
356 * trust me - if it happens it does suck.
357 */
358
eurwdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)359 static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code,
360 void *unused)
361 {
362 if (code == SYS_DOWN || code == SYS_HALT)
363 eurwdt_disable_timer(); /* Turn the card off */
364
365 return NOTIFY_DONE;
366 }
367
368 /*
369 * Kernel Interfaces
370 */
371
372
373 static const struct file_operations eurwdt_fops = {
374 .owner = THIS_MODULE,
375 .llseek = no_llseek,
376 .write = eurwdt_write,
377 .unlocked_ioctl = eurwdt_ioctl,
378 .open = eurwdt_open,
379 .release = eurwdt_release,
380 };
381
382 static struct miscdevice eurwdt_miscdev = {
383 .minor = WATCHDOG_MINOR,
384 .name = "watchdog",
385 .fops = &eurwdt_fops,
386 };
387
388 /*
389 * The WDT card needs to learn about soft shutdowns in order to
390 * turn the timebomb registers off.
391 */
392
393 static struct notifier_block eurwdt_notifier = {
394 .notifier_call = eurwdt_notify_sys,
395 };
396
397 /**
398 * cleanup_module:
399 *
400 * Unload the watchdog. You cannot do this with any file handles open.
401 * If your watchdog is set to continue ticking on close and you unload
402 * it, well it keeps ticking. We won't get the interrupt but the board
403 * will not touch PC memory so all is fine. You just have to load a new
404 * module in 60 seconds or reboot.
405 */
406
eurwdt_exit(void)407 static void __exit eurwdt_exit(void)
408 {
409 eurwdt_lock_chip();
410
411 misc_deregister(&eurwdt_miscdev);
412
413 unregister_reboot_notifier(&eurwdt_notifier);
414 release_region(io, 2);
415 free_irq(irq, NULL);
416 }
417
418 /**
419 * eurwdt_init:
420 *
421 * Set up the WDT watchdog board. After grabbing the resources
422 * we require we need also to unlock the device.
423 * The open() function will actually kick the board off.
424 */
425
eurwdt_init(void)426 static int __init eurwdt_init(void)
427 {
428 int ret;
429
430 ret = request_irq(irq, eurwdt_interrupt, 0, "eurwdt", NULL);
431 if (ret) {
432 pr_err("IRQ %d is not free\n", irq);
433 goto out;
434 }
435
436 if (!request_region(io, 2, "eurwdt")) {
437 pr_err("IO %X is not free\n", io);
438 ret = -EBUSY;
439 goto outirq;
440 }
441
442 ret = register_reboot_notifier(&eurwdt_notifier);
443 if (ret) {
444 pr_err("can't register reboot notifier (err=%d)\n", ret);
445 goto outreg;
446 }
447
448 ret = misc_register(&eurwdt_miscdev);
449 if (ret) {
450 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
451 goto outreboot;
452 }
453
454 eurwdt_unlock_chip();
455
456 ret = 0;
457 pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n",
458 io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
459
460 out:
461 return ret;
462
463 outreboot:
464 unregister_reboot_notifier(&eurwdt_notifier);
465
466 outreg:
467 release_region(io, 2);
468
469 outirq:
470 free_irq(irq, NULL);
471 goto out;
472 }
473
474 module_init(eurwdt_init);
475 module_exit(eurwdt_exit);
476
477 MODULE_AUTHOR("Rodolfo Giometti");
478 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
479 MODULE_LICENSE("GPL");
480 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
481