1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Advantech Single Board Computer WDT driver |
4 | * |
5 | * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> |
6 | * |
7 | * Based on acquirewdt.c which is based on wdt.c. |
8 | * Original copyright messages: |
9 | * |
10 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
11 | * All Rights Reserved. |
12 | * |
13 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
14 | * warranty for any of this software. This material is provided |
15 | * "AS-IS" and at no charge. |
16 | * |
17 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
18 | * |
19 | * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> |
20 | * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT |
21 | * |
22 | * 16-Oct-2002 Rob Radez <rob@osinvestor.com> |
23 | * Clean up ioctls, clean up init + exit, add expect close support, |
24 | * add wdt_start and wdt_stop as parameters. |
25 | */ |
26 | |
27 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
28 | |
29 | #include <linux/module.h> |
30 | #include <linux/moduleparam.h> |
31 | #include <linux/types.h> |
32 | #include <linux/miscdevice.h> |
33 | #include <linux/watchdog.h> |
34 | #include <linux/fs.h> |
35 | #include <linux/ioport.h> |
36 | #include <linux/platform_device.h> |
37 | #include <linux/init.h> |
38 | #include <linux/io.h> |
39 | #include <linux/uaccess.h> |
40 | |
41 | |
42 | #define DRV_NAME "advantechwdt" |
43 | #define WATCHDOG_NAME "Advantech WDT" |
44 | #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ |
45 | |
46 | /* the watchdog platform device */ |
47 | static struct platform_device *advwdt_platform_device; |
48 | static unsigned long advwdt_is_open; |
49 | static char adv_expect_close; |
50 | |
51 | /* |
52 | * You must set these - there is no sane way to probe for this board. |
53 | * |
54 | * To enable or restart, write the timeout value in seconds (1 to 63) |
55 | * to I/O port wdt_start. To disable, read I/O port wdt_stop. |
56 | * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but |
57 | * check your manual (at least the PCA-6159 seems to be different - |
58 | * the manual says wdt_stop is 0x43, not 0x443). |
59 | * (0x43 is also a write-only control register for the 8254 timer!) |
60 | */ |
61 | |
62 | static int wdt_stop = 0x443; |
63 | module_param(wdt_stop, int, 0); |
64 | MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)" ); |
65 | |
66 | static int wdt_start = 0x443; |
67 | module_param(wdt_start, int, 0); |
68 | MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)" ); |
69 | |
70 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ |
71 | module_param(timeout, int, 0); |
72 | MODULE_PARM_DESC(timeout, |
73 | "Watchdog timeout in seconds. 1<= timeout <=63, default=" |
74 | __MODULE_STRING(WATCHDOG_TIMEOUT) "." ); |
75 | |
76 | static bool nowayout = WATCHDOG_NOWAYOUT; |
77 | module_param(nowayout, bool, 0); |
78 | MODULE_PARM_DESC(nowayout, |
79 | "Watchdog cannot be stopped once started (default=" |
80 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
81 | |
82 | /* |
83 | * Watchdog Operations |
84 | */ |
85 | |
86 | static void advwdt_ping(void) |
87 | { |
88 | /* Write a watchdog value */ |
89 | outb_p(value: timeout, port: wdt_start); |
90 | } |
91 | |
92 | static void advwdt_disable(void) |
93 | { |
94 | inb_p(port: wdt_stop); |
95 | } |
96 | |
97 | static int advwdt_set_heartbeat(int t) |
98 | { |
99 | if (t < 1 || t > 63) |
100 | return -EINVAL; |
101 | timeout = t; |
102 | return 0; |
103 | } |
104 | |
105 | /* |
106 | * /dev/watchdog handling |
107 | */ |
108 | |
109 | static ssize_t advwdt_write(struct file *file, const char __user *buf, |
110 | size_t count, loff_t *ppos) |
111 | { |
112 | if (count) { |
113 | if (!nowayout) { |
114 | size_t i; |
115 | |
116 | adv_expect_close = 0; |
117 | |
118 | for (i = 0; i != count; i++) { |
119 | char c; |
120 | if (get_user(c, buf + i)) |
121 | return -EFAULT; |
122 | if (c == 'V') |
123 | adv_expect_close = 42; |
124 | } |
125 | } |
126 | advwdt_ping(); |
127 | } |
128 | return count; |
129 | } |
130 | |
131 | static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
132 | { |
133 | int new_timeout; |
134 | void __user *argp = (void __user *)arg; |
135 | int __user *p = argp; |
136 | static const struct watchdog_info ident = { |
137 | .options = WDIOF_KEEPALIVEPING | |
138 | WDIOF_SETTIMEOUT | |
139 | WDIOF_MAGICCLOSE, |
140 | .firmware_version = 1, |
141 | .identity = WATCHDOG_NAME, |
142 | }; |
143 | |
144 | switch (cmd) { |
145 | case WDIOC_GETSUPPORT: |
146 | if (copy_to_user(to: argp, from: &ident, n: sizeof(ident))) |
147 | return -EFAULT; |
148 | break; |
149 | |
150 | case WDIOC_GETSTATUS: |
151 | case WDIOC_GETBOOTSTATUS: |
152 | return put_user(0, p); |
153 | |
154 | case WDIOC_SETOPTIONS: |
155 | { |
156 | int options, retval = -EINVAL; |
157 | |
158 | if (get_user(options, p)) |
159 | return -EFAULT; |
160 | if (options & WDIOS_DISABLECARD) { |
161 | advwdt_disable(); |
162 | retval = 0; |
163 | } |
164 | if (options & WDIOS_ENABLECARD) { |
165 | advwdt_ping(); |
166 | retval = 0; |
167 | } |
168 | return retval; |
169 | } |
170 | case WDIOC_KEEPALIVE: |
171 | advwdt_ping(); |
172 | break; |
173 | |
174 | case WDIOC_SETTIMEOUT: |
175 | if (get_user(new_timeout, p)) |
176 | return -EFAULT; |
177 | if (advwdt_set_heartbeat(t: new_timeout)) |
178 | return -EINVAL; |
179 | advwdt_ping(); |
180 | fallthrough; |
181 | case WDIOC_GETTIMEOUT: |
182 | return put_user(timeout, p); |
183 | default: |
184 | return -ENOTTY; |
185 | } |
186 | return 0; |
187 | } |
188 | |
189 | static int advwdt_open(struct inode *inode, struct file *file) |
190 | { |
191 | if (test_and_set_bit(nr: 0, addr: &advwdt_is_open)) |
192 | return -EBUSY; |
193 | /* |
194 | * Activate |
195 | */ |
196 | |
197 | advwdt_ping(); |
198 | return stream_open(inode, filp: file); |
199 | } |
200 | |
201 | static int advwdt_close(struct inode *inode, struct file *file) |
202 | { |
203 | if (adv_expect_close == 42) { |
204 | advwdt_disable(); |
205 | } else { |
206 | pr_crit("Unexpected close, not stopping watchdog!\n" ); |
207 | advwdt_ping(); |
208 | } |
209 | clear_bit(nr: 0, addr: &advwdt_is_open); |
210 | adv_expect_close = 0; |
211 | return 0; |
212 | } |
213 | |
214 | /* |
215 | * Kernel Interfaces |
216 | */ |
217 | |
218 | static const struct file_operations advwdt_fops = { |
219 | .owner = THIS_MODULE, |
220 | .llseek = no_llseek, |
221 | .write = advwdt_write, |
222 | .unlocked_ioctl = advwdt_ioctl, |
223 | .compat_ioctl = compat_ptr_ioctl, |
224 | .open = advwdt_open, |
225 | .release = advwdt_close, |
226 | }; |
227 | |
228 | static struct miscdevice advwdt_miscdev = { |
229 | .minor = WATCHDOG_MINOR, |
230 | .name = "watchdog" , |
231 | .fops = &advwdt_fops, |
232 | }; |
233 | |
234 | /* |
235 | * Init & exit routines |
236 | */ |
237 | |
238 | static int __init advwdt_probe(struct platform_device *dev) |
239 | { |
240 | int ret; |
241 | |
242 | if (wdt_stop != wdt_start) { |
243 | if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { |
244 | pr_err("I/O address 0x%04x already in use\n" , |
245 | wdt_stop); |
246 | ret = -EIO; |
247 | goto out; |
248 | } |
249 | } |
250 | |
251 | if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { |
252 | pr_err("I/O address 0x%04x already in use\n" , wdt_start); |
253 | ret = -EIO; |
254 | goto unreg_stop; |
255 | } |
256 | |
257 | /* Check that the heartbeat value is within it's range ; |
258 | * if not reset to the default */ |
259 | if (advwdt_set_heartbeat(t: timeout)) { |
260 | advwdt_set_heartbeat(WATCHDOG_TIMEOUT); |
261 | pr_info("timeout value must be 1<=x<=63, using %d\n" , timeout); |
262 | } |
263 | |
264 | ret = misc_register(misc: &advwdt_miscdev); |
265 | if (ret != 0) { |
266 | pr_err("cannot register miscdev on minor=%d (err=%d)\n" , |
267 | WATCHDOG_MINOR, ret); |
268 | goto unreg_regions; |
269 | } |
270 | pr_info("initialized. timeout=%d sec (nowayout=%d)\n" , |
271 | timeout, nowayout); |
272 | out: |
273 | return ret; |
274 | unreg_regions: |
275 | release_region(wdt_start, 1); |
276 | unreg_stop: |
277 | if (wdt_stop != wdt_start) |
278 | release_region(wdt_stop, 1); |
279 | goto out; |
280 | } |
281 | |
282 | static void advwdt_remove(struct platform_device *dev) |
283 | { |
284 | misc_deregister(misc: &advwdt_miscdev); |
285 | release_region(wdt_start, 1); |
286 | if (wdt_stop != wdt_start) |
287 | release_region(wdt_stop, 1); |
288 | } |
289 | |
290 | static void advwdt_shutdown(struct platform_device *dev) |
291 | { |
292 | /* Turn the WDT off if we have a soft shutdown */ |
293 | advwdt_disable(); |
294 | } |
295 | |
296 | static struct platform_driver advwdt_driver = { |
297 | .remove_new = advwdt_remove, |
298 | .shutdown = advwdt_shutdown, |
299 | .driver = { |
300 | .name = DRV_NAME, |
301 | }, |
302 | }; |
303 | |
304 | static int __init advwdt_init(void) |
305 | { |
306 | int err; |
307 | |
308 | pr_info("WDT driver for Advantech single board computer initialising\n" ); |
309 | |
310 | advwdt_platform_device = platform_device_register_simple(DRV_NAME, |
311 | id: -1, NULL, num: 0); |
312 | if (IS_ERR(ptr: advwdt_platform_device)) |
313 | return PTR_ERR(ptr: advwdt_platform_device); |
314 | |
315 | err = platform_driver_probe(&advwdt_driver, advwdt_probe); |
316 | if (err) |
317 | goto unreg_platform_device; |
318 | |
319 | return 0; |
320 | |
321 | unreg_platform_device: |
322 | platform_device_unregister(advwdt_platform_device); |
323 | return err; |
324 | } |
325 | |
326 | static void __exit advwdt_exit(void) |
327 | { |
328 | platform_device_unregister(advwdt_platform_device); |
329 | platform_driver_unregister(&advwdt_driver); |
330 | pr_info("Watchdog Module Unloaded\n" ); |
331 | } |
332 | |
333 | module_init(advwdt_init); |
334 | module_exit(advwdt_exit); |
335 | |
336 | MODULE_LICENSE("GPL" ); |
337 | MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>" ); |
338 | MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver" ); |
339 | |