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
65static unsigned long eurwdt_is_open;
66static int eurwdt_timeout;
67static char eur_expect_close;
68static DEFINE_SPINLOCK(eurwdt_lock);
69
70/*
71 * You must set these - there is no sane way to probe for this board.
72 */
73
74static int io = 0x3f0;
75static int irq = 10;
76static char *ev = "int";
77
78#define WDT_TIMEOUT		60                /* 1 minute */
79
80static bool nowayout = WATCHDOG_NOWAYOUT;
81module_param(nowayout, bool, 0);
82MODULE_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
100module_param(io, int, 0);
101MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
102module_param(irq, int, 0);
103MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
104module_param(ev, charp, 0);
105MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
106
107
108/*
109 * Programming support
110 */
111
112static inline void eurwdt_write_reg(u8 index, u8 data)
113{
114	outb(index, io);
115	outb(data, io+1);
116}
117
118static inline void eurwdt_lock_chip(void)
119{
120	outb(0xaa, io);
121}
122
123static inline void eurwdt_unlock_chip(void)
124{
125	outb(0x55, io);
126	eurwdt_write_reg(0x07, 0x08);	/* set the logical device */
127}
128
129static inline void eurwdt_set_timeout(int timeout)
130{
131	eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
132}
133
134static inline void eurwdt_disable_timer(void)
135{
136	eurwdt_set_timeout(0);
137}
138
139static 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
165static 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
185static 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
202static ssize_t eurwdt_write(struct file *file, const char __user *buf,
203size_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
236static 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
312static 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
334static 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
359static 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
373static 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
382static 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
393static 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
407static 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
426static 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
460out:
461	return ret;
462
463outreboot:
464	unregister_reboot_notifier(&eurwdt_notifier);
465
466outreg:
467	release_region(io, 2);
468
469outirq:
470	free_irq(irq, NULL);
471	goto out;
472}
473
474module_init(eurwdt_init);
475module_exit(eurwdt_exit);
476
477MODULE_AUTHOR("Rodolfo Giometti");
478MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
479MODULE_LICENSE("GPL");
480