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 #include <linux/interrupt.h>
49 #include <linux/module.h>
50 #include <linux/moduleparam.h>
51 #include <linux/types.h>
52 #include <linux/miscdevice.h>
53 #include <linux/watchdog.h>
54 #include <linux/fs.h>
55 #include <linux/ioport.h>
56 #include <linux/notifier.h>
57 #include <linux/reboot.h>
58 #include <linux/init.h>
59 #include <linux/io.h>
60 #include <linux/uaccess.h>
61 
62 #include <asm/system.h>
63 
64 static unsigned long eurwdt_is_open;
65 static int eurwdt_timeout;
66 static char eur_expect_close;
67 static spinlock_t eurwdt_lock;
68 
69 /*
70  * You must set these - there is no sane way to probe for this board.
71  */
72 
73 static int io = 0x3f0;
74 static int irq = 10;
75 static char *ev = "int";
76 
77 #define WDT_TIMEOUT		60                /* 1 minute */
78 
79 static int nowayout = WATCHDOG_NOWAYOUT;
80 module_param(nowayout, int, 0);
81 MODULE_PARM_DESC(nowayout,
82 		"Watchdog cannot be stopped once started (default="
83 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
84 
85 /*
86  * Some symbolic names
87  */
88 
89 #define WDT_CTRL_REG		0x30
90 #define WDT_OUTPIN_CFG		0xe2
91 #define WDT_EVENT_INT		0x00
92 #define WDT_EVENT_REBOOT	0x08
93 #define WDT_UNIT_SEL		0xf1
94 #define WDT_UNIT_SECS		0x80
95 #define WDT_TIMEOUT_VAL		0xf2
96 #define WDT_TIMER_CFG		0xf3
97 
98 
99 module_param(io, int, 0);
100 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
101 module_param(irq, int, 0);
102 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
103 module_param(ev, charp, 0);
104 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
105 
106 
107 /*
108  * Programming support
109  */
110 
111 static inline void eurwdt_write_reg(u8 index, u8 data)
112 {
113 	outb(index, io);
114 	outb(data, io+1);
115 }
116 
117 static inline void eurwdt_lock_chip(void)
118 {
119 	outb(0xaa, io);
120 }
121 
122 static inline void eurwdt_unlock_chip(void)
123 {
124 	outb(0x55, io);
125 	eurwdt_write_reg(0x07, 0x08);	/* set the logical device */
126 }
127 
128 static inline void eurwdt_set_timeout(int timeout)
129 {
130 	eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
131 }
132 
133 static inline void eurwdt_disable_timer(void)
134 {
135 	eurwdt_set_timeout(0);
136 }
137 
138 static void eurwdt_activate_timer(void)
139 {
140 	eurwdt_disable_timer();
141 	eurwdt_write_reg(WDT_CTRL_REG, 0x01);	/* activate the WDT */
142 	eurwdt_write_reg(WDT_OUTPIN_CFG,
143 		!strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
144 
145 	/* Setting interrupt line */
146 	if (irq == 2 || irq > 15 || irq < 0) {
147 		printk(KERN_ERR ": invalid irq number\n");
148 		irq = 0;	/* if invalid we disable interrupt */
149 	}
150 	if (irq == 0)
151 		printk(KERN_INFO ": interrupt disabled\n");
152 
153 	eurwdt_write_reg(WDT_TIMER_CFG, irq << 4);
154 
155 	eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS);	/* we use seconds */
156 	eurwdt_set_timeout(0);	/* the default timeout */
157 }
158 
159 
160 /*
161  * Kernel methods.
162  */
163 
164 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
165 {
166 	printk(KERN_CRIT "timeout WDT timeout\n");
167 
168 #ifdef ONLY_TESTING
169 	printk(KERN_CRIT "Would Reboot.\n");
170 #else
171 	printk(KERN_CRIT "Initiating system reboot.\n");
172 	emergency_restart();
173 #endif
174 	return IRQ_HANDLED;
175 }
176 
177 
178 /**
179  * eurwdt_ping:
180  *
181  * Reload counter one with the watchdog timeout.
182  */
183 
184 static void eurwdt_ping(void)
185 {
186 	/* Write the watchdog default value */
187 	eurwdt_set_timeout(eurwdt_timeout);
188 }
189 
190 /**
191  * eurwdt_write:
192  * @file: file handle to the watchdog
193  * @buf: buffer to write (unused as data does not matter here
194  * @count: count of bytes
195  * @ppos: pointer to the position to write. No seeks allowed
196  *
197  * A write to a watchdog device is defined as a keepalive signal. Any
198  * write of data will do, as we we don't define content meaning.
199  */
200 
201 static ssize_t eurwdt_write(struct file *file, const char __user *buf,
202 size_t count, loff_t *ppos)
203 {
204 	if (count) 	{
205 		if (!nowayout) {
206 			size_t i;
207 
208 			eur_expect_close = 0;
209 
210 			for (i = 0; i != count; i++) {
211 				char c;
212 				if (get_user(c, buf + i))
213 					return -EFAULT;
214 				if (c == 'V')
215 					eur_expect_close = 42;
216 			}
217 		}
218 		spin_lock(&eurwdt_lock);
219 		eurwdt_ping();	/* the default timeout */
220 		spin_unlock(&eurwdt_lock);
221 	}
222 	return count;
223 }
224 
225 /**
226  * eurwdt_ioctl:
227  * @file: file handle to the device
228  * @cmd: watchdog command
229  * @arg: argument pointer
230  *
231  * The watchdog API defines a common set of functions for all watchdogs
232  * according to their available features.
233  */
234 
235 static long eurwdt_ioctl(struct file *file,
236 					unsigned int cmd, unsigned long arg)
237 {
238 	void __user *argp = (void __user *)arg;
239 	int __user *p = argp;
240 	static const struct watchdog_info ident = {
241 		.options	  = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
242 							| WDIOF_MAGICCLOSE,
243 		.firmware_version = 1,
244 		.identity	  = "WDT Eurotech CPU-1220/1410",
245 	};
246 
247 	int time;
248 	int options, retval = -EINVAL;
249 
250 	switch (cmd) {
251 	case WDIOC_GETSUPPORT:
252 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
253 
254 	case WDIOC_GETSTATUS:
255 	case WDIOC_GETBOOTSTATUS:
256 		return put_user(0, p);
257 
258 	case WDIOC_SETOPTIONS:
259 		if (get_user(options, p))
260 			return -EFAULT;
261 		spin_lock(&eurwdt_lock);
262 		if (options & WDIOS_DISABLECARD) {
263 			eurwdt_disable_timer();
264 			retval = 0;
265 		}
266 		if (options & WDIOS_ENABLECARD) {
267 			eurwdt_activate_timer();
268 			eurwdt_ping();
269 			retval = 0;
270 		}
271 		spin_unlock(&eurwdt_lock);
272 		return retval;
273 
274 	case WDIOC_KEEPALIVE:
275 		spin_lock(&eurwdt_lock);
276 		eurwdt_ping();
277 		spin_unlock(&eurwdt_lock);
278 		return 0;
279 
280 	case WDIOC_SETTIMEOUT:
281 		if (copy_from_user(&time, p, sizeof(int)))
282 			return -EFAULT;
283 
284 		/* Sanity check */
285 		if (time < 0 || time > 255)
286 			return -EINVAL;
287 
288 		spin_lock(&eurwdt_lock);
289 		eurwdt_timeout = time;
290 		eurwdt_set_timeout(time);
291 		spin_unlock(&eurwdt_lock);
292 		/* Fall */
293 
294 	case WDIOC_GETTIMEOUT:
295 		return put_user(eurwdt_timeout, p);
296 
297 	default:
298 		return -ENOTTY;
299 	}
300 }
301 
302 /**
303  * eurwdt_open:
304  * @inode: inode of device
305  * @file: file handle to device
306  *
307  * The misc device has been opened. The watchdog device is single
308  * open and on opening we load the counter.
309  */
310 
311 static int eurwdt_open(struct inode *inode, struct file *file)
312 {
313 	if (test_and_set_bit(0, &eurwdt_is_open))
314 		return -EBUSY;
315 	eurwdt_timeout = WDT_TIMEOUT;	/* initial timeout */
316 	/* Activate the WDT */
317 	eurwdt_activate_timer();
318 	return nonseekable_open(inode, file);
319 }
320 
321 /**
322  * eurwdt_release:
323  * @inode: inode to board
324  * @file: file handle to board
325  *
326  * The watchdog has a configurable API. There is a religious dispute
327  * between people who want their watchdog to be able to shut down and
328  * those who want to be sure if the watchdog manager dies the machine
329  * reboots. In the former case we disable the counters, in the latter
330  * case you have to open it again very soon.
331  */
332 
333 static int eurwdt_release(struct inode *inode, struct file *file)
334 {
335 	if (eur_expect_close == 42)
336 		eurwdt_disable_timer();
337 	else {
338 		printk(KERN_CRIT
339 			"eurwdt: 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 
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 
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 
426 static int __init eurwdt_init(void)
427 {
428 	int ret;
429 
430 	ret = request_irq(irq, eurwdt_interrupt, IRQF_DISABLED, "eurwdt", NULL);
431 	if (ret) {
432 		printk(KERN_ERR "eurwdt: IRQ %d is not free.\n", irq);
433 		goto out;
434 	}
435 
436 	if (!request_region(io, 2, "eurwdt")) {
437 		printk(KERN_ERR "eurwdt: 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 		printk(KERN_ERR
445 		    "eurwdt: can't register reboot notifier (err=%d)\n", ret);
446 		goto outreg;
447 	}
448 
449 	spin_lock_init(&eurwdt_lock);
450 
451 	ret = misc_register(&eurwdt_miscdev);
452 	if (ret) {
453 		printk(KERN_ERR "eurwdt: can't misc_register on minor=%d\n",
454 		WATCHDOG_MINOR);
455 		goto outreboot;
456 	}
457 
458 	eurwdt_unlock_chip();
459 
460 	ret = 0;
461 	printk(KERN_INFO "Eurotech WDT driver 0.01 at %X (Interrupt %d)"
462 		" - timeout event: %s\n",
463 		io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
464 
465 out:
466 	return ret;
467 
468 outreboot:
469 	unregister_reboot_notifier(&eurwdt_notifier);
470 
471 outreg:
472 	release_region(io, 2);
473 
474 outirq:
475 	free_irq(irq, NULL);
476 	goto out;
477 }
478 
479 module_init(eurwdt_init);
480 module_exit(eurwdt_exit);
481 
482 MODULE_AUTHOR("Rodolfo Giometti");
483 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
484 MODULE_LICENSE("GPL");
485 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
486