xref: /openbmc/linux/drivers/watchdog/mixcomwd.c (revision b6dfb247)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * MixCom Watchdog: A Simple Hardware Watchdog Device
4  * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis
5  *
6  * Author: Gergely Madarasz <gorgo@itc.hu>
7  *
8  * Copyright (c) 1999 ITConsult-Pro Co. <info@itc.hu>
9  *
10  * Version 0.1 (99/04/15):
11  *		- first version
12  *
13  * Version 0.2 (99/06/16):
14  *		- added kernel timer watchdog ping after close
15  *		  since the hardware does not support watchdog shutdown
16  *
17  * Version 0.3 (99/06/21):
18  *		- added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls
19  *
20  * Version 0.3.1 (99/06/22):
21  *		- allow module removal while internal timer is active,
22  *		  print warning about probable reset
23  *
24  * Version 0.4 (99/11/15):
25  *		- support for one more type board
26  *
27  * Version 0.5 (2001/12/14) Matt Domsch <Matt_Domsch@dell.com>
28  *		- added nowayout module option to override
29  *		  CONFIG_WATCHDOG_NOWAYOUT
30  *
31  * Version 0.6 (2002/04/12): Rob Radez <rob@osinvestor.com>
32  *		- make mixcomwd_opened unsigned,
33  *		  removed lock_kernel/unlock_kernel from mixcomwd_release,
34  *		  modified ioctl a bit to conform to API
35  */
36 
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38 
39 #define VERSION "0.6"
40 #define WATCHDOG_NAME "mixcomwd"
41 
42 #include <linux/module.h>
43 #include <linux/moduleparam.h>
44 #include <linux/types.h>
45 #include <linux/miscdevice.h>
46 #include <linux/ioport.h>
47 #include <linux/watchdog.h>
48 #include <linux/fs.h>
49 #include <linux/reboot.h>
50 #include <linux/init.h>
51 #include <linux/jiffies.h>
52 #include <linux/timer.h>
53 #include <linux/uaccess.h>
54 #include <linux/io.h>
55 
56 /*
57  * We have two types of cards that can be probed:
58  * 1) The Mixcom cards: these cards can be found at addresses
59  *    0x180, 0x280, 0x380 with an additional offset of 0xc10.
60  *    (Or 0xd90, 0xe90, 0xf90).
61  * 2) The FlashCOM cards: these cards can be set up at
62  *    0x300 -> 0x378, in 0x8 jumps with an offset of 0x04.
63  *    (Or 0x304 -> 0x37c in 0x8 jumps).
64  *    Each card has it's own ID.
65  */
66 #define MIXCOM_ID 0x11
67 #define FLASHCOM_ID 0x18
68 static struct {
69 	int ioport;
70 	int id;
71 } mixcomwd_io_info[] = {
72 	/* The Mixcom cards */
73 	{0x0d90, MIXCOM_ID},
74 	{0x0e90, MIXCOM_ID},
75 	{0x0f90, MIXCOM_ID},
76 	/* The FlashCOM cards */
77 	{0x0304, FLASHCOM_ID},
78 	{0x030c, FLASHCOM_ID},
79 	{0x0314, FLASHCOM_ID},
80 	{0x031c, FLASHCOM_ID},
81 	{0x0324, FLASHCOM_ID},
82 	{0x032c, FLASHCOM_ID},
83 	{0x0334, FLASHCOM_ID},
84 	{0x033c, FLASHCOM_ID},
85 	{0x0344, FLASHCOM_ID},
86 	{0x034c, FLASHCOM_ID},
87 	{0x0354, FLASHCOM_ID},
88 	{0x035c, FLASHCOM_ID},
89 	{0x0364, FLASHCOM_ID},
90 	{0x036c, FLASHCOM_ID},
91 	{0x0374, FLASHCOM_ID},
92 	{0x037c, FLASHCOM_ID},
93 	/* The end of the list */
94 	{0x0000, 0},
95 };
96 
97 static void mixcomwd_timerfun(struct timer_list *unused);
98 
99 static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
100 
101 static int watchdog_port;
102 static int mixcomwd_timer_alive;
103 static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun);
104 static char expect_close;
105 
106 static bool nowayout = WATCHDOG_NOWAYOUT;
107 module_param(nowayout, bool, 0);
108 MODULE_PARM_DESC(nowayout,
109 		"Watchdog cannot be stopped once started (default="
110 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
111 
mixcomwd_ping(void)112 static void mixcomwd_ping(void)
113 {
114 	outb_p(55, watchdog_port);
115 	return;
116 }
117 
mixcomwd_timerfun(struct timer_list * unused)118 static void mixcomwd_timerfun(struct timer_list *unused)
119 {
120 	mixcomwd_ping();
121 	mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
122 }
123 
124 /*
125  *	Allow only one person to hold it open
126  */
127 
mixcomwd_open(struct inode * inode,struct file * file)128 static int mixcomwd_open(struct inode *inode, struct file *file)
129 {
130 	if (test_and_set_bit(0, &mixcomwd_opened))
131 		return -EBUSY;
132 
133 	mixcomwd_ping();
134 
135 	if (nowayout)
136 		/*
137 		 * fops_get() code via open() has already done
138 		 * a try_module_get() so it is safe to do the
139 		 * __module_get().
140 		 */
141 		__module_get(THIS_MODULE);
142 	else {
143 		if (mixcomwd_timer_alive) {
144 			del_timer(&mixcomwd_timer);
145 			mixcomwd_timer_alive = 0;
146 		}
147 	}
148 	return stream_open(inode, file);
149 }
150 
mixcomwd_release(struct inode * inode,struct file * file)151 static int mixcomwd_release(struct inode *inode, struct file *file)
152 {
153 	if (expect_close == 42) {
154 		if (mixcomwd_timer_alive) {
155 			pr_err("release called while internal timer alive\n");
156 			return -EBUSY;
157 		}
158 		mixcomwd_timer_alive = 1;
159 		mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
160 	} else
161 		pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
162 
163 	clear_bit(0, &mixcomwd_opened);
164 	expect_close = 0;
165 	return 0;
166 }
167 
168 
mixcomwd_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)169 static ssize_t mixcomwd_write(struct file *file, const char __user *data,
170 						size_t len, loff_t *ppos)
171 {
172 	if (len) {
173 		if (!nowayout) {
174 			size_t i;
175 
176 			/* In case it was set long ago */
177 			expect_close = 0;
178 
179 			for (i = 0; i != len; i++) {
180 				char c;
181 				if (get_user(c, data + i))
182 					return -EFAULT;
183 				if (c == 'V')
184 					expect_close = 42;
185 			}
186 		}
187 		mixcomwd_ping();
188 	}
189 	return len;
190 }
191 
mixcomwd_ioctl(struct file * file,unsigned int cmd,unsigned long arg)192 static long mixcomwd_ioctl(struct file *file,
193 				unsigned int cmd, unsigned long arg)
194 {
195 	void __user *argp = (void __user *)arg;
196 	int __user *p = argp;
197 	int status;
198 	static const struct watchdog_info ident = {
199 		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
200 		.firmware_version = 1,
201 		.identity = "MixCOM watchdog",
202 	};
203 
204 	switch (cmd) {
205 	case WDIOC_GETSUPPORT:
206 		if (copy_to_user(argp, &ident, sizeof(ident)))
207 			return -EFAULT;
208 		break;
209 	case WDIOC_GETSTATUS:
210 		status = mixcomwd_opened;
211 		if (!nowayout)
212 			status |= mixcomwd_timer_alive;
213 		return put_user(status, p);
214 	case WDIOC_GETBOOTSTATUS:
215 		return put_user(0, p);
216 	case WDIOC_KEEPALIVE:
217 		mixcomwd_ping();
218 		break;
219 	default:
220 		return -ENOTTY;
221 	}
222 	return 0;
223 }
224 
225 static const struct file_operations mixcomwd_fops = {
226 	.owner		= THIS_MODULE,
227 	.llseek		= no_llseek,
228 	.write		= mixcomwd_write,
229 	.unlocked_ioctl	= mixcomwd_ioctl,
230 	.compat_ioctl	= compat_ptr_ioctl,
231 	.open		= mixcomwd_open,
232 	.release	= mixcomwd_release,
233 };
234 
235 static struct miscdevice mixcomwd_miscdev = {
236 	.minor	= WATCHDOG_MINOR,
237 	.name	= "watchdog",
238 	.fops	= &mixcomwd_fops,
239 };
240 
checkcard(int port,int card_id)241 static int __init checkcard(int port, int card_id)
242 {
243 	int id;
244 
245 	if (!request_region(port, 1, "MixCOM watchdog"))
246 		return 0;
247 
248 	id = inb_p(port);
249 	if (card_id == MIXCOM_ID)
250 		id &= 0x3f;
251 
252 	if (id != card_id) {
253 		release_region(port, 1);
254 		return 0;
255 	}
256 	return 1;
257 }
258 
mixcomwd_init(void)259 static int __init mixcomwd_init(void)
260 {
261 	int i, ret, found = 0;
262 
263 	for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {
264 		if (checkcard(mixcomwd_io_info[i].ioport,
265 			      mixcomwd_io_info[i].id)) {
266 			found = 1;
267 			watchdog_port = mixcomwd_io_info[i].ioport;
268 		}
269 	}
270 
271 	if (!found) {
272 		pr_err("No card detected, or port not available\n");
273 		return -ENODEV;
274 	}
275 
276 	ret = misc_register(&mixcomwd_miscdev);
277 	if (ret) {
278 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
279 		       WATCHDOG_MINOR, ret);
280 		goto error_misc_register_watchdog;
281 	}
282 
283 	pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",
284 		VERSION, watchdog_port);
285 
286 	return 0;
287 
288 error_misc_register_watchdog:
289 	release_region(watchdog_port, 1);
290 	watchdog_port = 0x0000;
291 	return ret;
292 }
293 
mixcomwd_exit(void)294 static void __exit mixcomwd_exit(void)
295 {
296 	if (!nowayout) {
297 		if (mixcomwd_timer_alive) {
298 			pr_warn("I quit now, hardware will probably reboot!\n");
299 			del_timer_sync(&mixcomwd_timer);
300 			mixcomwd_timer_alive = 0;
301 		}
302 	}
303 	misc_deregister(&mixcomwd_miscdev);
304 	release_region(watchdog_port, 1);
305 }
306 
307 module_init(mixcomwd_init);
308 module_exit(mixcomwd_exit);
309 
310 MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
311 MODULE_DESCRIPTION("MixCom Watchdog driver");
312 MODULE_VERSION(VERSION);
313 MODULE_LICENSE("GPL");
314