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 | |
112 | static void mixcomwd_ping(void) |
113 | { |
114 | outb_p(value: 55, port: watchdog_port); |
115 | return; |
116 | } |
117 | |
118 | static void mixcomwd_timerfun(struct timer_list *unused) |
119 | { |
120 | mixcomwd_ping(); |
121 | mod_timer(timer: &mixcomwd_timer, expires: jiffies + 5 * HZ); |
122 | } |
123 | |
124 | /* |
125 | * Allow only one person to hold it open |
126 | */ |
127 | |
128 | static int mixcomwd_open(struct inode *inode, struct file *file) |
129 | { |
130 | if (test_and_set_bit(nr: 0, addr: &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(timer: &mixcomwd_timer); |
145 | mixcomwd_timer_alive = 0; |
146 | } |
147 | } |
148 | return stream_open(inode, filp: file); |
149 | } |
150 | |
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(timer: &mixcomwd_timer, expires: jiffies + 5 * HZ); |
160 | } else |
161 | pr_crit("WDT device closed unexpectedly. WDT will not stop!\n" ); |
162 | |
163 | clear_bit(nr: 0, addr: &mixcomwd_opened); |
164 | expect_close = 0; |
165 | return 0; |
166 | } |
167 | |
168 | |
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 | |
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(to: argp, from: &ident, n: 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 | |
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 | |
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(port: mixcomwd_io_info[i].ioport, |
265 | card_id: 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(misc: &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 | |
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(timer: &mixcomwd_timer); |
300 | mixcomwd_timer_alive = 0; |
301 | } |
302 | } |
303 | misc_deregister(misc: &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 | |