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 
112 static inline void eurwdt_write_reg(u8 index, u8 data)
113 {
114 	outb(index, io);
115 	outb(data, io+1);
116 }
117 
118 static inline void eurwdt_lock_chip(void)
119 {
120 	outb(0xaa, io);
121 }
122 
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 
129 static inline void eurwdt_set_timeout(int timeout)
130 {
131 	eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
132 }
133 
134 static inline void eurwdt_disable_timer(void)
135 {
136 	eurwdt_set_timeout(0);
137 }
138 
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 
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 
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 
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 
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 
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 
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 
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, 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