1/*
2 * MixCom Watchdog: A Simple Hardware Watchdog Device
3 * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis
4 *
5 * Author: Gergely Madarasz <gorgo@itc.hu>
6 *
7 * Copyright (c) 1999 ITConsult-Pro Co. <info@itc.hu>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 *
14 * Version 0.1 (99/04/15):
15 *		- first version
16 *
17 * Version 0.2 (99/06/16):
18 *		- added kernel timer watchdog ping after close
19 *		  since the hardware does not support watchdog shutdown
20 *
21 * Version 0.3 (99/06/21):
22 *		- added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls
23 *
24 * Version 0.3.1 (99/06/22):
25 *		- allow module removal while internal timer is active,
26 *		  print warning about probable reset
27 *
28 * Version 0.4 (99/11/15):
29 *		- support for one more type board
30 *
31 * Version 0.5 (2001/12/14) Matt Domsch <Matt_Domsch@dell.com>
32 *              - added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
33 *
34 */
35
36#define VERSION "0.5"
37
38#include <linux/module.h>
39#include <linux/moduleparam.h>
40#include <linux/types.h>
41#include <linux/miscdevice.h>
42#include <linux/ioport.h>
43#include <linux/watchdog.h>
44#include <linux/fs.h>
45#include <linux/reboot.h>
46#include <linux/init.h>
47#include <linux/jiffies.h>
48#include <linux/timer.h>
49#include <asm/uaccess.h>
50#include <asm/io.h>
51
52static int mixcomwd_ioports[] = { 0x180, 0x280, 0x380, 0x000 };
53
54#define MIXCOM_WATCHDOG_OFFSET 0xc10
55#define MIXCOM_ID 0x11
56#define FLASHCOM_WATCHDOG_OFFSET 0x4
57#define FLASHCOM_ID 0x18
58
59static void mixcomwd_timerfun(unsigned long d);
60
61static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
62
63static int watchdog_port;
64static int mixcomwd_timer_alive;
65static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun, 0, 0);
66static char expect_close;
67
68static int nowayout = WATCHDOG_NOWAYOUT;
69module_param(nowayout, int, 0);
70MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71
72static void mixcomwd_ping(void)
73{
74	outb_p(55,watchdog_port);
75	return;
76}
77
78static void mixcomwd_timerfun(unsigned long d)
79{
80	mixcomwd_ping();
81
82	mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
83}
84
85/*
86 *	Allow only one person to hold it open
87 */
88
89static int mixcomwd_open(struct inode *inode, struct file *file)
90{
91	if(test_and_set_bit(0,&mixcomwd_opened)) {
92		return -EBUSY;
93	}
94	mixcomwd_ping();
95
96	if (nowayout) {
97		/*
98		 * fops_get() code via open() has already done
99		 * a try_module_get() so it is safe to do the
100		 * __module_get().
101		 */
102		__module_get(THIS_MODULE);
103	} else {
104		if(mixcomwd_timer_alive) {
105			del_timer(&mixcomwd_timer);
106			mixcomwd_timer_alive=0;
107		}
108	}
109	return nonseekable_open(inode, file);
110}
111
112static int mixcomwd_release(struct inode *inode, struct file *file)
113{
114	if (expect_close == 42) {
115		if(mixcomwd_timer_alive) {
116			printk(KERN_ERR "mixcomwd: release called while internal timer alive");
117			return -EBUSY;
118		}
119		mixcomwd_timer_alive=1;
120		mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
121	} else {
122		printk(KERN_CRIT "mixcomwd: WDT device closed unexpectedly.  WDT will not stop!\n");
123	}
124
125	clear_bit(0,&mixcomwd_opened);
126	expect_close=0;
127	return 0;
128}
129
130
131static ssize_t mixcomwd_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
132{
133	if(len)
134	{
135		if (!nowayout) {
136			size_t i;
137
138			/* In case it was set long ago */
139			expect_close = 0;
140
141			for (i = 0; i != len; i++) {
142				char c;
143				if (get_user(c, data + i))
144					return -EFAULT;
145				if (c == 'V')
146					expect_close = 42;
147			}
148		}
149		mixcomwd_ping();
150	}
151	return len;
152}
153
154static int mixcomwd_ioctl(struct inode *inode, struct file *file,
155	unsigned int cmd, unsigned long arg)
156{
157	void __user *argp = (void __user *)arg;
158	int __user *p = argp;
159	int status;
160	static struct watchdog_info ident = {
161		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
162		.firmware_version = 1,
163		.identity = "MixCOM watchdog",
164	};
165
166	switch(cmd)
167	{
168		case WDIOC_GETSTATUS:
169			status=mixcomwd_opened;
170			if (!nowayout) {
171				status|=mixcomwd_timer_alive;
172			}
173			if (copy_to_user(p, &status, sizeof(int))) {
174				return -EFAULT;
175			}
176			break;
177		case WDIOC_GETSUPPORT:
178			if (copy_to_user(argp, &ident, sizeof(ident))) {
179				return -EFAULT;
180			}
181			break;
182		case WDIOC_KEEPALIVE:
183			mixcomwd_ping();
184			break;
185		default:
186			return -ENOTTY;
187	}
188	return 0;
189}
190
191static const struct file_operations mixcomwd_fops=
192{
193	.owner		= THIS_MODULE,
194	.llseek		= no_llseek,
195	.write		= mixcomwd_write,
196	.ioctl		= mixcomwd_ioctl,
197	.open		= mixcomwd_open,
198	.release	= mixcomwd_release,
199};
200
201static struct miscdevice mixcomwd_miscdev=
202{
203	.minor	= WATCHDOG_MINOR,
204	.name	= "watchdog",
205	.fops	= &mixcomwd_fops,
206};
207
208static int __init mixcomwd_checkcard(int port)
209{
210	int id;
211
212	port += MIXCOM_WATCHDOG_OFFSET;
213	if (!request_region(port, 1, "MixCOM watchdog")) {
214		return 0;
215	}
216
217	id=inb_p(port) & 0x3f;
218	if(id!=MIXCOM_ID) {
219		release_region(port, 1);
220		return 0;
221	}
222	return port;
223}
224
225static int __init flashcom_checkcard(int port)
226{
227	int id;
228
229	port += FLASHCOM_WATCHDOG_OFFSET;
230	if (!request_region(port, 1, "MixCOM watchdog")) {
231		return 0;
232	}
233
234	id=inb_p(port);
235 	if(id!=FLASHCOM_ID) {
236		release_region(port, 1);
237		return 0;
238	}
239 	return port;
240 }
241
242static int __init mixcomwd_init(void)
243{
244	int i;
245	int ret;
246	int found=0;
247
248	for (i = 0; !found && mixcomwd_ioports[i] != 0; i++) {
249		watchdog_port = mixcomwd_checkcard(mixcomwd_ioports[i]);
250		if (watchdog_port) {
251			found = 1;
252		}
253	}
254
255	/* The FlashCOM card can be set up at 0x300 -> 0x378, in 0x8 jumps */
256	for (i = 0x300; !found && i < 0x380; i+=0x8) {
257		watchdog_port = flashcom_checkcard(i);
258		if (watchdog_port) {
259			found = 1;
260		}
261	}
262
263	if (!found) {
264		printk("mixcomwd: No card detected, or port not available.\n");
265		return -ENODEV;
266	}
267
268	ret = misc_register(&mixcomwd_miscdev);
269	if (ret)
270	{
271		release_region(watchdog_port, 1);
272		return ret;
273	}
274
275	printk(KERN_INFO "MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",VERSION,watchdog_port);
276
277	return 0;
278}
279
280static void __exit mixcomwd_exit(void)
281{
282	if (!nowayout) {
283		if(mixcomwd_timer_alive) {
284			printk(KERN_WARNING "mixcomwd: I quit now, hardware will"
285			       " probably reboot!\n");
286			del_timer_sync(&mixcomwd_timer);
287			mixcomwd_timer_alive=0;
288		}
289	}
290	release_region(watchdog_port,1);
291	misc_deregister(&mixcomwd_miscdev);
292}
293
294module_init(mixcomwd_init);
295module_exit(mixcomwd_exit);
296
297MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
298MODULE_DESCRIPTION("MixCom Watchdog driver");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
301