Commit | Line | Data |
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d0173278 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
1da177e4 LT |
2 | /* |
3 | * Acquire Single Board Computer Watchdog Timer driver | |
4 | * | |
143a2e54 | 5 | * Based on wdt.c. Original copyright messages: |
1da177e4 | 6 | * |
29fa0586 AC |
7 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
8 | * All Rights Reserved. | |
1da177e4 | 9 | * |
1da177e4 LT |
10 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
11 | * warranty for any of this software. This material is provided | |
12 | * "AS-IS" and at no charge. | |
13 | * | |
29fa0586 | 14 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
1da177e4 | 15 | * |
143a2e54 WVS |
16 | * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> |
17 | * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT | |
18 | * Can't add timeout - driver doesn't allow changing value | |
1da177e4 LT |
19 | */ |
20 | ||
21 | /* | |
22 | * Theory of Operation: | |
23 | * The Watch-Dog Timer is provided to ensure that standalone | |
24 | * Systems can always recover from catastrophic conditions that | |
25985edc | 25 | * caused the CPU to crash. This condition may have occurred by |
1da177e4 LT |
26 | * external EMI or a software bug. When the CPU stops working |
27 | * correctly, hardware on the board will either perform a hardware | |
28 | * reset (cold boot) or a non-maskable interrupt (NMI) to bring the | |
29 | * system back to a known state. | |
30 | * | |
31 | * The Watch-Dog Timer is controlled by two I/O Ports. | |
32 | * 443 hex - Read - Enable or refresh the Watch-Dog Timer | |
33 | * 043 hex - Read - Disable the Watch-Dog Timer | |
34 | * | |
35 | * To enable the Watch-Dog Timer, a read from I/O port 443h must | |
36 | * be performed. This will enable and activate the countdown timer | |
37 | * which will eventually time out and either reset the CPU or cause | |
38 | * an NMI depending on the setting of a jumper. To ensure that this | |
39 | * reset condition does not occur, the Watch-Dog Timer must be | |
40 | * periodically refreshed by reading the same I/O port 443h. | |
41 | * The Watch-Dog Timer is disabled by reading I/O port 043h. | |
42 | * | |
43 | * The Watch-Dog Timer Time-Out Period is set via jumpers. | |
44 | * It can be 1, 2, 10, 20, 110 or 220 seconds. | |
45 | */ | |
46 | ||
76c11f04 WVS |
47 | /* |
48 | * Includes, defines, variables, module parameters, ... | |
49 | */ | |
1da177e4 | 50 | |
27c766aa JP |
51 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
52 | ||
76c11f04 WVS |
53 | /* Includes */ |
54 | #include <linux/module.h> /* For module specific items */ | |
55 | #include <linux/moduleparam.h> /* For new moduleparam's */ | |
56 | #include <linux/types.h> /* For standard types (like size_t) */ | |
57 | #include <linux/errno.h> /* For the -ENODEV/... values */ | |
58 | #include <linux/kernel.h> /* For printk/panic/... */ | |
487722cf | 59 | #include <linux/miscdevice.h> /* For struct miscdevice */ |
76c11f04 WVS |
60 | #include <linux/watchdog.h> /* For the watchdog specific items */ |
61 | #include <linux/fs.h> /* For file operations */ | |
62 | #include <linux/ioport.h> /* For io-port access */ | |
ad5fe323 | 63 | #include <linux/platform_device.h> /* For platform_driver framework */ |
76c11f04 | 64 | #include <linux/init.h> /* For __init/__exit/... */ |
94da1e2e AC |
65 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
66 | #include <linux/io.h> /* For inb/outb/... */ | |
76c11f04 WVS |
67 | |
68 | /* Module information */ | |
69 | #define DRV_NAME "acquirewdt" | |
1da177e4 | 70 | #define WATCHDOG_NAME "Acquire WDT" |
94da1e2e AC |
71 | /* There is no way to see what the correct time-out period is */ |
72 | #define WATCHDOG_HEARTBEAT 0 | |
1da177e4 | 73 | |
76c11f04 | 74 | /* internal variables */ |
94da1e2e AC |
75 | /* the watchdog platform device */ |
76 | static struct platform_device *acq_platform_device; | |
1da177e4 LT |
77 | static unsigned long acq_is_open; |
78 | static char expect_close; | |
79 | ||
76c11f04 | 80 | /* module parameters */ |
94da1e2e AC |
81 | /* You must set this - there is no sane way to probe for this board. */ |
82 | static int wdt_stop = 0x43; | |
1da177e4 LT |
83 | module_param(wdt_stop, int, 0); |
84 | MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)"); | |
85 | ||
94da1e2e AC |
86 | /* You must set this - there is no sane way to probe for this board. */ |
87 | static int wdt_start = 0x443; | |
1da177e4 LT |
88 | module_param(wdt_start, int, 0); |
89 | MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)"); | |
90 | ||
86a1e189 WVS |
91 | static bool nowayout = WATCHDOG_NOWAYOUT; |
92 | module_param(nowayout, bool, 0); | |
94da1e2e AC |
93 | MODULE_PARM_DESC(nowayout, |
94 | "Watchdog cannot be stopped once started (default=" | |
95 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 LT |
96 | |
97 | /* | |
76c11f04 | 98 | * Watchdog Operations |
1da177e4 LT |
99 | */ |
100 | ||
101 | static void acq_keepalive(void) | |
102 | { | |
103 | /* Write a watchdog value */ | |
104 | inb_p(wdt_start); | |
105 | } | |
106 | ||
107 | static void acq_stop(void) | |
108 | { | |
109 | /* Turn the card off */ | |
110 | inb_p(wdt_stop); | |
111 | } | |
112 | ||
113 | /* | |
76c11f04 | 114 | * /dev/watchdog handling |
1da177e4 LT |
115 | */ |
116 | ||
94da1e2e AC |
117 | static ssize_t acq_write(struct file *file, const char __user *buf, |
118 | size_t count, loff_t *ppos) | |
1da177e4 LT |
119 | { |
120 | /* See if we got the magic character 'V' and reload the timer */ | |
94da1e2e | 121 | if (count) { |
1da177e4 LT |
122 | if (!nowayout) { |
123 | size_t i; | |
1da177e4 | 124 | /* note: just in case someone wrote the magic character |
7944d3a5 | 125 | five months ago... */ |
1da177e4 | 126 | expect_close = 0; |
94da1e2e AC |
127 | /* scan to see whether or not we got the |
128 | magic character */ | |
1da177e4 LT |
129 | for (i = 0; i != count; i++) { |
130 | char c; | |
131 | if (get_user(c, buf + i)) | |
132 | return -EFAULT; | |
133 | if (c == 'V') | |
134 | expect_close = 42; | |
135 | } | |
136 | } | |
94da1e2e AC |
137 | /* Well, anyhow someone wrote to us, we should |
138 | return that favour */ | |
1da177e4 LT |
139 | acq_keepalive(); |
140 | } | |
141 | return count; | |
142 | } | |
143 | ||
94da1e2e | 144 | static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
145 | { |
146 | int options, retval = -EINVAL; | |
147 | void __user *argp = (void __user *)arg; | |
148 | int __user *p = argp; | |
42747d71 | 149 | static const struct watchdog_info ident = { |
1da177e4 LT |
150 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
151 | .firmware_version = 1, | |
76c11f04 | 152 | .identity = WATCHDOG_NAME, |
1da177e4 LT |
153 | }; |
154 | ||
94da1e2e | 155 | switch (cmd) { |
1da177e4 | 156 | case WDIOC_GETSUPPORT: |
94da1e2e | 157 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
1da177e4 LT |
158 | |
159 | case WDIOC_GETSTATUS: | |
160 | case WDIOC_GETBOOTSTATUS: | |
94da1e2e | 161 | return put_user(0, p); |
1da177e4 | 162 | |
1da177e4 LT |
163 | case WDIOC_SETOPTIONS: |
164 | { | |
94da1e2e AC |
165 | if (get_user(options, p)) |
166 | return -EFAULT; | |
167 | if (options & WDIOS_DISABLECARD) { | |
168 | acq_stop(); | |
169 | retval = 0; | |
170 | } | |
171 | if (options & WDIOS_ENABLECARD) { | |
172 | acq_keepalive(); | |
173 | retval = 0; | |
174 | } | |
175 | return retval; | |
1da177e4 | 176 | } |
0c06090c WVS |
177 | case WDIOC_KEEPALIVE: |
178 | acq_keepalive(); | |
179 | return 0; | |
180 | ||
181 | case WDIOC_GETTIMEOUT: | |
182 | return put_user(WATCHDOG_HEARTBEAT, p); | |
183 | ||
1da177e4 | 184 | default: |
94da1e2e | 185 | return -ENOTTY; |
1da177e4 LT |
186 | } |
187 | } | |
188 | ||
189 | static int acq_open(struct inode *inode, struct file *file) | |
190 | { | |
191 | if (test_and_set_bit(0, &acq_is_open)) | |
192 | return -EBUSY; | |
193 | ||
194 | if (nowayout) | |
195 | __module_get(THIS_MODULE); | |
196 | ||
197 | /* Activate */ | |
198 | acq_keepalive(); | |
c5bf68fe | 199 | return stream_open(inode, file); |
1da177e4 LT |
200 | } |
201 | ||
202 | static int acq_close(struct inode *inode, struct file *file) | |
203 | { | |
204 | if (expect_close == 42) { | |
205 | acq_stop(); | |
206 | } else { | |
27c766aa | 207 | pr_crit("Unexpected close, not stopping watchdog!\n"); |
1da177e4 LT |
208 | acq_keepalive(); |
209 | } | |
210 | clear_bit(0, &acq_is_open); | |
211 | expect_close = 0; | |
212 | return 0; | |
213 | } | |
214 | ||
1da177e4 LT |
215 | /* |
216 | * Kernel Interfaces | |
217 | */ | |
218 | ||
62322d25 | 219 | static const struct file_operations acq_fops = { |
1da177e4 LT |
220 | .owner = THIS_MODULE, |
221 | .llseek = no_llseek, | |
222 | .write = acq_write, | |
94da1e2e | 223 | .unlocked_ioctl = acq_ioctl, |
b6dfb247 | 224 | .compat_ioctl = compat_ptr_ioctl, |
1da177e4 LT |
225 | .open = acq_open, |
226 | .release = acq_close, | |
227 | }; | |
228 | ||
76c11f04 WVS |
229 | static struct miscdevice acq_miscdev = { |
230 | .minor = WATCHDOG_MINOR, | |
231 | .name = "watchdog", | |
232 | .fops = &acq_fops, | |
1da177e4 LT |
233 | }; |
234 | ||
76c11f04 WVS |
235 | /* |
236 | * Init & exit routines | |
237 | */ | |
238 | ||
b0e0b4b5 | 239 | static int __init acq_probe(struct platform_device *dev) |
1da177e4 LT |
240 | { |
241 | int ret; | |
242 | ||
1da177e4 LT |
243 | if (wdt_stop != wdt_start) { |
244 | if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { | |
27c766aa | 245 | pr_err("I/O address 0x%04x already in use\n", wdt_stop); |
1da177e4 LT |
246 | ret = -EIO; |
247 | goto out; | |
248 | } | |
249 | } | |
250 | ||
251 | if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { | |
27c766aa | 252 | pr_err("I/O address 0x%04x already in use\n", wdt_start); |
1da177e4 LT |
253 | ret = -EIO; |
254 | goto unreg_stop; | |
255 | } | |
1da177e4 LT |
256 | ret = misc_register(&acq_miscdev); |
257 | if (ret != 0) { | |
27c766aa JP |
258 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
259 | WATCHDOG_MINOR, ret); | |
98c08e98 | 260 | goto unreg_regions; |
1da177e4 | 261 | } |
27c766aa | 262 | pr_info("initialized. (nowayout=%d)\n", nowayout); |
1da177e4 LT |
263 | |
264 | return 0; | |
1da177e4 LT |
265 | unreg_regions: |
266 | release_region(wdt_start, 1); | |
267 | unreg_stop: | |
268 | if (wdt_stop != wdt_start) | |
269 | release_region(wdt_stop, 1); | |
270 | out: | |
271 | return ret; | |
272 | } | |
273 | ||
4b12b896 | 274 | static int acq_remove(struct platform_device *dev) |
1da177e4 LT |
275 | { |
276 | misc_deregister(&acq_miscdev); | |
94da1e2e AC |
277 | release_region(wdt_start, 1); |
278 | if (wdt_stop != wdt_start) | |
279 | release_region(wdt_stop, 1); | |
ad5fe323 WVS |
280 | |
281 | return 0; | |
282 | } | |
283 | ||
98c08e98 WVS |
284 | static void acq_shutdown(struct platform_device *dev) |
285 | { | |
286 | /* Turn the WDT off if we have a soft shutdown */ | |
287 | acq_stop(); | |
288 | } | |
289 | ||
ad5fe323 | 290 | static struct platform_driver acquirewdt_driver = { |
82268714 | 291 | .remove = acq_remove, |
98c08e98 | 292 | .shutdown = acq_shutdown, |
ad5fe323 | 293 | .driver = { |
ad5fe323 WVS |
294 | .name = DRV_NAME, |
295 | }, | |
296 | }; | |
297 | ||
298 | static int __init acq_init(void) | |
299 | { | |
300 | int err; | |
301 | ||
27c766aa | 302 | pr_info("WDT driver for Acquire single board computer initialising\n"); |
ad5fe323 | 303 | |
94da1e2e AC |
304 | acq_platform_device = platform_device_register_simple(DRV_NAME, |
305 | -1, NULL, 0); | |
b0e0b4b5 JD |
306 | if (IS_ERR(acq_platform_device)) |
307 | return PTR_ERR(acq_platform_device); | |
308 | ||
309 | err = platform_driver_probe(&acquirewdt_driver, acq_probe); | |
310 | if (err) | |
311 | goto unreg_platform_device; | |
ad5fe323 WVS |
312 | return 0; |
313 | ||
b0e0b4b5 JD |
314 | unreg_platform_device: |
315 | platform_device_unregister(acq_platform_device); | |
ad5fe323 WVS |
316 | return err; |
317 | } | |
318 | ||
319 | static void __exit acq_exit(void) | |
320 | { | |
321 | platform_device_unregister(acq_platform_device); | |
322 | platform_driver_unregister(&acquirewdt_driver); | |
27c766aa | 323 | pr_info("Watchdog Module Unloaded\n"); |
1da177e4 LT |
324 | } |
325 | ||
326 | module_init(acq_init); | |
327 | module_exit(acq_exit); | |
328 | ||
329 | MODULE_AUTHOR("David Woodhouse"); | |
330 | MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); | |
331 | MODULE_LICENSE("GPL"); |