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 .write = mixcomwd_write,
228 .unlocked_ioctl = mixcomwd_ioctl,
229 .compat_ioctl = compat_ptr_ioctl,
230 .open = mixcomwd_open,
231 .release = mixcomwd_release,
232 };
233
234 static struct miscdevice mixcomwd_miscdev = {
235 .minor = WATCHDOG_MINOR,
236 .name = "watchdog",
237 .fops = &mixcomwd_fops,
238 };
239
checkcard(int port,int card_id)240 static int __init checkcard(int port, int card_id)
241 {
242 int id;
243
244 if (!request_region(port, 1, "MixCOM watchdog"))
245 return 0;
246
247 id = inb_p(port);
248 if (card_id == MIXCOM_ID)
249 id &= 0x3f;
250
251 if (id != card_id) {
252 release_region(port, 1);
253 return 0;
254 }
255 return 1;
256 }
257
mixcomwd_init(void)258 static int __init mixcomwd_init(void)
259 {
260 int i, ret, found = 0;
261
262 for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {
263 if (checkcard(mixcomwd_io_info[i].ioport,
264 mixcomwd_io_info[i].id)) {
265 found = 1;
266 watchdog_port = mixcomwd_io_info[i].ioport;
267 }
268 }
269
270 if (!found) {
271 pr_err("No card detected, or port not available\n");
272 return -ENODEV;
273 }
274
275 ret = misc_register(&mixcomwd_miscdev);
276 if (ret) {
277 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
278 WATCHDOG_MINOR, ret);
279 goto error_misc_register_watchdog;
280 }
281
282 pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",
283 VERSION, watchdog_port);
284
285 return 0;
286
287 error_misc_register_watchdog:
288 release_region(watchdog_port, 1);
289 watchdog_port = 0x0000;
290 return ret;
291 }
292
mixcomwd_exit(void)293 static void __exit mixcomwd_exit(void)
294 {
295 if (!nowayout) {
296 if (mixcomwd_timer_alive) {
297 pr_warn("I quit now, hardware will probably reboot!\n");
298 del_timer_sync(&mixcomwd_timer);
299 mixcomwd_timer_alive = 0;
300 }
301 }
302 misc_deregister(&mixcomwd_miscdev);
303 release_region(watchdog_port, 1);
304 }
305
306 module_init(mixcomwd_init);
307 module_exit(mixcomwd_exit);
308
309 MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
310 MODULE_DESCRIPTION("MixCom Watchdog driver");
311 MODULE_VERSION(VERSION);
312 MODULE_LICENSE("GPL");
313