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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
33 *		  CONFIG_WATCHDOG_NOWAYOUT
34 *
35 * Version 0.6 (2002/04/12): Rob Radez <rob@osinvestor.com>
36 *		- make mixcomwd_opened unsigned,
37 *		  removed lock_kernel/unlock_kernel from mixcomwd_release,
38 *		  modified ioctl a bit to conform to API
39 *
40 */
41
42#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
43
44#define VERSION "0.6"
45#define WATCHDOG_NAME "mixcomwd"
46
47#include <linux/module.h>
48#include <linux/moduleparam.h>
49#include <linux/types.h>
50#include <linux/miscdevice.h>
51#include <linux/ioport.h>
52#include <linux/watchdog.h>
53#include <linux/fs.h>
54#include <linux/reboot.h>
55#include <linux/init.h>
56#include <linux/jiffies.h>
57#include <linux/timer.h>
58#include <linux/uaccess.h>
59#include <linux/io.h>
60
61/*
62 * We have two types of cards that can be probed:
63 * 1) The Mixcom cards: these cards can be found at addresses
64 *    0x180, 0x280, 0x380 with an additional offset of 0xc10.
65 *    (Or 0xd90, 0xe90, 0xf90).
66 * 2) The FlashCOM cards: these cards can be set up at
67 *    0x300 -> 0x378, in 0x8 jumps with an offset of 0x04.
68 *    (Or 0x304 -> 0x37c in 0x8 jumps).
69 *    Each card has it's own ID.
70 */
71#define MIXCOM_ID 0x11
72#define FLASHCOM_ID 0x18
73static struct {
74	int ioport;
75	int id;
76} mixcomwd_io_info[] = {
77	/* The Mixcom cards */
78	{0x0d90, MIXCOM_ID},
79	{0x0e90, MIXCOM_ID},
80	{0x0f90, MIXCOM_ID},
81	/* The FlashCOM cards */
82	{0x0304, FLASHCOM_ID},
83	{0x030c, FLASHCOM_ID},
84	{0x0314, FLASHCOM_ID},
85	{0x031c, FLASHCOM_ID},
86	{0x0324, FLASHCOM_ID},
87	{0x032c, FLASHCOM_ID},
88	{0x0334, FLASHCOM_ID},
89	{0x033c, FLASHCOM_ID},
90	{0x0344, FLASHCOM_ID},
91	{0x034c, FLASHCOM_ID},
92	{0x0354, FLASHCOM_ID},
93	{0x035c, FLASHCOM_ID},
94	{0x0364, FLASHCOM_ID},
95	{0x036c, FLASHCOM_ID},
96	{0x0374, FLASHCOM_ID},
97	{0x037c, FLASHCOM_ID},
98	/* The end of the list */
99	{0x0000, 0},
100};
101
102static void mixcomwd_timerfun(unsigned long d);
103
104static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
105
106static int watchdog_port;
107static int mixcomwd_timer_alive;
108static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun, 0, 0);
109static char expect_close;
110
111static bool nowayout = WATCHDOG_NOWAYOUT;
112module_param(nowayout, bool, 0);
113MODULE_PARM_DESC(nowayout,
114		"Watchdog cannot be stopped once started (default="
115				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
116
117static void mixcomwd_ping(void)
118{
119	outb_p(55, watchdog_port);
120	return;
121}
122
123static void mixcomwd_timerfun(unsigned long d)
124{
125	mixcomwd_ping();
126	mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
127}
128
129/*
130 *	Allow only one person to hold it open
131 */
132
133static int mixcomwd_open(struct inode *inode, struct file *file)
134{
135	if (test_and_set_bit(0, &mixcomwd_opened))
136		return -EBUSY;
137
138	mixcomwd_ping();
139
140	if (nowayout)
141		/*
142		 * fops_get() code via open() has already done
143		 * a try_module_get() so it is safe to do the
144		 * __module_get().
145		 */
146		__module_get(THIS_MODULE);
147	else {
148		if (mixcomwd_timer_alive) {
149			del_timer(&mixcomwd_timer);
150			mixcomwd_timer_alive = 0;
151		}
152	}
153	return nonseekable_open(inode, file);
154}
155
156static int mixcomwd_release(struct inode *inode, struct file *file)
157{
158	if (expect_close == 42) {
159		if (mixcomwd_timer_alive) {
160			pr_err("release called while internal timer alive\n");
161			return -EBUSY;
162		}
163		mixcomwd_timer_alive = 1;
164		mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
165	} else
166		pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
167
168	clear_bit(0, &mixcomwd_opened);
169	expect_close = 0;
170	return 0;
171}
172
173
174static ssize_t mixcomwd_write(struct file *file, const char __user *data,
175						size_t len, loff_t *ppos)
176{
177	if (len) {
178		if (!nowayout) {
179			size_t i;
180
181			/* In case it was set long ago */
182			expect_close = 0;
183
184			for (i = 0; i != len; i++) {
185				char c;
186				if (get_user(c, data + i))
187					return -EFAULT;
188				if (c == 'V')
189					expect_close = 42;
190			}
191		}
192		mixcomwd_ping();
193	}
194	return len;
195}
196
197static long mixcomwd_ioctl(struct file *file,
198				unsigned int cmd, unsigned long arg)
199{
200	void __user *argp = (void __user *)arg;
201	int __user *p = argp;
202	int status;
203	static const struct watchdog_info ident = {
204		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
205		.firmware_version = 1,
206		.identity = "MixCOM watchdog",
207	};
208
209	switch (cmd) {
210	case WDIOC_GETSUPPORT:
211		if (copy_to_user(argp, &ident, sizeof(ident)))
212			return -EFAULT;
213		break;
214	case WDIOC_GETSTATUS:
215		status = mixcomwd_opened;
216		if (!nowayout)
217			status |= mixcomwd_timer_alive;
218		return put_user(status, p);
219	case WDIOC_GETBOOTSTATUS:
220		return put_user(0, p);
221	case WDIOC_KEEPALIVE:
222		mixcomwd_ping();
223		break;
224	default:
225		return -ENOTTY;
226	}
227	return 0;
228}
229
230static const struct file_operations mixcomwd_fops = {
231	.owner		= THIS_MODULE,
232	.llseek		= no_llseek,
233	.write		= mixcomwd_write,
234	.unlocked_ioctl	= mixcomwd_ioctl,
235	.open		= mixcomwd_open,
236	.release	= mixcomwd_release,
237};
238
239static struct miscdevice mixcomwd_miscdev = {
240	.minor	= WATCHDOG_MINOR,
241	.name	= "watchdog",
242	.fops	= &mixcomwd_fops,
243};
244
245static int __init checkcard(int port, int card_id)
246{
247	int id;
248
249	if (!request_region(port, 1, "MixCOM watchdog"))
250		return 0;
251
252	id = inb_p(port);
253	if (card_id == MIXCOM_ID)
254		id &= 0x3f;
255
256	if (id != card_id) {
257		release_region(port, 1);
258		return 0;
259	}
260	return 1;
261}
262
263static int __init mixcomwd_init(void)
264{
265	int i, ret, found = 0;
266
267	for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {
268		if (checkcard(mixcomwd_io_info[i].ioport,
269			      mixcomwd_io_info[i].id)) {
270			found = 1;
271			watchdog_port = mixcomwd_io_info[i].ioport;
272		}
273	}
274
275	if (!found) {
276		pr_err("No card detected, or port not available\n");
277		return -ENODEV;
278	}
279
280	ret = misc_register(&mixcomwd_miscdev);
281	if (ret) {
282		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
283		       WATCHDOG_MINOR, ret);
284		goto error_misc_register_watchdog;
285	}
286
287	pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",
288		VERSION, watchdog_port);
289
290	return 0;
291
292error_misc_register_watchdog:
293	release_region(watchdog_port, 1);
294	watchdog_port = 0x0000;
295	return ret;
296}
297
298static void __exit mixcomwd_exit(void)
299{
300	if (!nowayout) {
301		if (mixcomwd_timer_alive) {
302			pr_warn("I quit now, hardware will probably reboot!\n");
303			del_timer_sync(&mixcomwd_timer);
304			mixcomwd_timer_alive = 0;
305		}
306	}
307	misc_deregister(&mixcomwd_miscdev);
308	release_region(watchdog_port, 1);
309}
310
311module_init(mixcomwd_init);
312module_exit(mixcomwd_exit);
313
314MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
315MODULE_DESCRIPTION("MixCom Watchdog driver");
316MODULE_VERSION(VERSION);
317MODULE_LICENSE("GPL");
318