1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * ICP Wafer 5823 Single Board Computer WDT driver |
4 | * http://www.icpamerica.com/wafer_5823.php |
5 | * May also work on other similar models |
6 | * |
7 | * (c) Copyright 2002 Justin Cormack <justin@street-vision.com> |
8 | * |
9 | * Release 0.02 |
10 | * |
11 | * Based on advantechwdt.c which is based on wdt.c. |
12 | * Original copyright messages: |
13 | * |
14 | * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
15 | * All Rights Reserved. |
16 | * |
17 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
18 | * warranty for any of this software. This material is provided |
19 | * "AS-IS" and at no charge. |
20 | * |
21 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
22 | * |
23 | */ |
24 | |
25 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
26 | |
27 | #include <linux/module.h> |
28 | #include <linux/moduleparam.h> |
29 | #include <linux/miscdevice.h> |
30 | #include <linux/watchdog.h> |
31 | #include <linux/fs.h> |
32 | #include <linux/ioport.h> |
33 | #include <linux/notifier.h> |
34 | #include <linux/reboot.h> |
35 | #include <linux/init.h> |
36 | #include <linux/spinlock.h> |
37 | #include <linux/io.h> |
38 | #include <linux/uaccess.h> |
39 | |
40 | #define WATCHDOG_NAME "Wafer 5823 WDT" |
41 | #define PFX WATCHDOG_NAME ": " |
42 | #define WD_TIMO 60 /* 60 sec default timeout */ |
43 | |
44 | static unsigned long wafwdt_is_open; |
45 | static char expect_close; |
46 | static DEFINE_SPINLOCK(wafwdt_lock); |
47 | |
48 | /* |
49 | * You must set these - there is no sane way to probe for this board. |
50 | * |
51 | * To enable, write the timeout value in seconds (1 to 255) to I/O |
52 | * port WDT_START, then read the port to start the watchdog. To pat |
53 | * the dog, read port WDT_STOP to stop the timer, then read WDT_START |
54 | * to restart it again. |
55 | */ |
56 | |
57 | static int wdt_stop = 0x843; |
58 | static int wdt_start = 0x443; |
59 | |
60 | static int timeout = WD_TIMO; /* in seconds */ |
61 | module_param(timeout, int, 0); |
62 | MODULE_PARM_DESC(timeout, |
63 | "Watchdog timeout in seconds. 1 <= timeout <= 255, default=" |
64 | __MODULE_STRING(WD_TIMO) "." ); |
65 | |
66 | static bool nowayout = WATCHDOG_NOWAYOUT; |
67 | module_param(nowayout, bool, 0); |
68 | MODULE_PARM_DESC(nowayout, |
69 | "Watchdog cannot be stopped once started (default=" |
70 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
71 | |
72 | static void wafwdt_ping(void) |
73 | { |
74 | /* pat watchdog */ |
75 | spin_lock(lock: &wafwdt_lock); |
76 | inb_p(port: wdt_stop); |
77 | inb_p(port: wdt_start); |
78 | spin_unlock(lock: &wafwdt_lock); |
79 | } |
80 | |
81 | static void wafwdt_start(void) |
82 | { |
83 | /* start up watchdog */ |
84 | outb_p(value: timeout, port: wdt_start); |
85 | inb_p(port: wdt_start); |
86 | } |
87 | |
88 | static void wafwdt_stop(void) |
89 | { |
90 | /* stop watchdog */ |
91 | inb_p(port: wdt_stop); |
92 | } |
93 | |
94 | static ssize_t wafwdt_write(struct file *file, const char __user *buf, |
95 | size_t count, loff_t *ppos) |
96 | { |
97 | /* See if we got the magic character 'V' and reload the timer */ |
98 | if (count) { |
99 | if (!nowayout) { |
100 | size_t i; |
101 | |
102 | /* In case it was set long ago */ |
103 | expect_close = 0; |
104 | |
105 | /* scan to see whether or not we got the magic |
106 | character */ |
107 | for (i = 0; i != count; i++) { |
108 | char c; |
109 | if (get_user(c, buf + i)) |
110 | return -EFAULT; |
111 | if (c == 'V') |
112 | expect_close = 42; |
113 | } |
114 | } |
115 | /* Well, anyhow someone wrote to us, we should |
116 | return that favour */ |
117 | wafwdt_ping(); |
118 | } |
119 | return count; |
120 | } |
121 | |
122 | static long wafwdt_ioctl(struct file *file, unsigned int cmd, |
123 | unsigned long arg) |
124 | { |
125 | int new_timeout; |
126 | void __user *argp = (void __user *)arg; |
127 | int __user *p = argp; |
128 | static const struct watchdog_info ident = { |
129 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
130 | WDIOF_MAGICCLOSE, |
131 | .firmware_version = 1, |
132 | .identity = "Wafer 5823 WDT" , |
133 | }; |
134 | |
135 | switch (cmd) { |
136 | case WDIOC_GETSUPPORT: |
137 | if (copy_to_user(to: argp, from: &ident, n: sizeof(ident))) |
138 | return -EFAULT; |
139 | break; |
140 | |
141 | case WDIOC_GETSTATUS: |
142 | case WDIOC_GETBOOTSTATUS: |
143 | return put_user(0, p); |
144 | |
145 | case WDIOC_SETOPTIONS: |
146 | { |
147 | int options, retval = -EINVAL; |
148 | |
149 | if (get_user(options, p)) |
150 | return -EFAULT; |
151 | |
152 | if (options & WDIOS_DISABLECARD) { |
153 | wafwdt_stop(); |
154 | retval = 0; |
155 | } |
156 | |
157 | if (options & WDIOS_ENABLECARD) { |
158 | wafwdt_start(); |
159 | retval = 0; |
160 | } |
161 | |
162 | return retval; |
163 | } |
164 | |
165 | case WDIOC_KEEPALIVE: |
166 | wafwdt_ping(); |
167 | break; |
168 | |
169 | case WDIOC_SETTIMEOUT: |
170 | if (get_user(new_timeout, p)) |
171 | return -EFAULT; |
172 | if ((new_timeout < 1) || (new_timeout > 255)) |
173 | return -EINVAL; |
174 | timeout = new_timeout; |
175 | wafwdt_stop(); |
176 | wafwdt_start(); |
177 | fallthrough; |
178 | case WDIOC_GETTIMEOUT: |
179 | return put_user(timeout, p); |
180 | |
181 | default: |
182 | return -ENOTTY; |
183 | } |
184 | return 0; |
185 | } |
186 | |
187 | static int wafwdt_open(struct inode *inode, struct file *file) |
188 | { |
189 | if (test_and_set_bit(nr: 0, addr: &wafwdt_is_open)) |
190 | return -EBUSY; |
191 | |
192 | /* |
193 | * Activate |
194 | */ |
195 | wafwdt_start(); |
196 | return stream_open(inode, filp: file); |
197 | } |
198 | |
199 | static int wafwdt_close(struct inode *inode, struct file *file) |
200 | { |
201 | if (expect_close == 42) |
202 | wafwdt_stop(); |
203 | else { |
204 | pr_crit("WDT device closed unexpectedly. WDT will not stop!\n" ); |
205 | wafwdt_ping(); |
206 | } |
207 | clear_bit(nr: 0, addr: &wafwdt_is_open); |
208 | expect_close = 0; |
209 | return 0; |
210 | } |
211 | |
212 | /* |
213 | * Notifier for system down |
214 | */ |
215 | |
216 | static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, |
217 | void *unused) |
218 | { |
219 | if (code == SYS_DOWN || code == SYS_HALT) |
220 | wafwdt_stop(); |
221 | return NOTIFY_DONE; |
222 | } |
223 | |
224 | /* |
225 | * Kernel Interfaces |
226 | */ |
227 | |
228 | static const struct file_operations wafwdt_fops = { |
229 | .owner = THIS_MODULE, |
230 | .llseek = no_llseek, |
231 | .write = wafwdt_write, |
232 | .unlocked_ioctl = wafwdt_ioctl, |
233 | .compat_ioctl = compat_ptr_ioctl, |
234 | .open = wafwdt_open, |
235 | .release = wafwdt_close, |
236 | }; |
237 | |
238 | static struct miscdevice wafwdt_miscdev = { |
239 | .minor = WATCHDOG_MINOR, |
240 | .name = "watchdog" , |
241 | .fops = &wafwdt_fops, |
242 | }; |
243 | |
244 | /* |
245 | * The WDT needs to learn about soft shutdowns in order to |
246 | * turn the timebomb registers off. |
247 | */ |
248 | |
249 | static struct notifier_block wafwdt_notifier = { |
250 | .notifier_call = wafwdt_notify_sys, |
251 | }; |
252 | |
253 | static int __init wafwdt_init(void) |
254 | { |
255 | int ret; |
256 | |
257 | pr_info("WDT driver for Wafer 5823 single board computer initialising\n" ); |
258 | |
259 | if (timeout < 1 || timeout > 255) { |
260 | timeout = WD_TIMO; |
261 | pr_info("timeout value must be 1 <= x <= 255, using %d\n" , |
262 | timeout); |
263 | } |
264 | |
265 | if (wdt_stop != wdt_start) { |
266 | if (!request_region(wdt_stop, 1, "Wafer 5823 WDT" )) { |
267 | pr_err("I/O address 0x%04x already in use\n" , wdt_stop); |
268 | ret = -EIO; |
269 | goto error; |
270 | } |
271 | } |
272 | |
273 | if (!request_region(wdt_start, 1, "Wafer 5823 WDT" )) { |
274 | pr_err("I/O address 0x%04x already in use\n" , wdt_start); |
275 | ret = -EIO; |
276 | goto error2; |
277 | } |
278 | |
279 | ret = register_reboot_notifier(&wafwdt_notifier); |
280 | if (ret != 0) { |
281 | pr_err("cannot register reboot notifier (err=%d)\n" , ret); |
282 | goto error3; |
283 | } |
284 | |
285 | ret = misc_register(misc: &wafwdt_miscdev); |
286 | if (ret != 0) { |
287 | pr_err("cannot register miscdev on minor=%d (err=%d)\n" , |
288 | WATCHDOG_MINOR, ret); |
289 | goto error4; |
290 | } |
291 | |
292 | pr_info("initialized. timeout=%d sec (nowayout=%d)\n" , |
293 | timeout, nowayout); |
294 | |
295 | return ret; |
296 | error4: |
297 | unregister_reboot_notifier(&wafwdt_notifier); |
298 | error3: |
299 | release_region(wdt_start, 1); |
300 | error2: |
301 | if (wdt_stop != wdt_start) |
302 | release_region(wdt_stop, 1); |
303 | error: |
304 | return ret; |
305 | } |
306 | |
307 | static void __exit wafwdt_exit(void) |
308 | { |
309 | misc_deregister(misc: &wafwdt_miscdev); |
310 | unregister_reboot_notifier(&wafwdt_notifier); |
311 | if (wdt_stop != wdt_start) |
312 | release_region(wdt_stop, 1); |
313 | release_region(wdt_start, 1); |
314 | } |
315 | |
316 | module_init(wafwdt_init); |
317 | module_exit(wafwdt_exit); |
318 | |
319 | MODULE_AUTHOR("Justin Cormack" ); |
320 | MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver" ); |
321 | MODULE_LICENSE("GPL" ); |
322 | |
323 | /* end of wafer5823wdt.c */ |
324 | |