1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Eurotech CPU-1220/1410/1420 on board WDT driver |
4 | * |
5 | * (c) Copyright 2001 Ascensit <support@ascensit.com> |
6 | * (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com> |
7 | * (c) Copyright 2002 Rob Radez <rob@osinvestor.com> |
8 | * |
9 | * Based on wdt.c. |
10 | * Original copyright messages: |
11 | * |
12 | * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
13 | * All Rights Reserved. |
14 | * |
15 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
16 | * warranty for any of this software. This material is provided |
17 | * "AS-IS" and at no charge. |
18 | * |
19 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>* |
20 | */ |
21 | |
22 | /* Changelog: |
23 | * |
24 | * 2001 - Rodolfo Giometti |
25 | * Initial release |
26 | * |
27 | * 2002/04/25 - Rob Radez |
28 | * clean up #includes |
29 | * clean up locking |
30 | * make __setup param unique |
31 | * proper options in watchdog_info |
32 | * add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls |
33 | * add expect_close support |
34 | * |
35 | * 2002.05.30 - Joel Becker <joel.becker@oracle.com> |
36 | * Added Matt Domsch's nowayout module option. |
37 | */ |
38 | |
39 | /* |
40 | * The eurotech CPU-1220/1410/1420's watchdog is a part |
41 | * of the on-board SUPER I/O device SMSC FDC 37B782. |
42 | */ |
43 | |
44 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
45 | |
46 | #include <linux/interrupt.h> |
47 | #include <linux/module.h> |
48 | #include <linux/moduleparam.h> |
49 | #include <linux/types.h> |
50 | #include <linux/miscdevice.h> |
51 | #include <linux/watchdog.h> |
52 | #include <linux/fs.h> |
53 | #include <linux/ioport.h> |
54 | #include <linux/notifier.h> |
55 | #include <linux/reboot.h> |
56 | #include <linux/init.h> |
57 | #include <linux/io.h> |
58 | #include <linux/uaccess.h> |
59 | |
60 | |
61 | static unsigned long eurwdt_is_open; |
62 | static int eurwdt_timeout; |
63 | static char eur_expect_close; |
64 | static DEFINE_SPINLOCK(eurwdt_lock); |
65 | |
66 | /* |
67 | * You must set these - there is no sane way to probe for this board. |
68 | */ |
69 | |
70 | static int io = 0x3f0; |
71 | static int irq = 10; |
72 | static char *ev = "int" ; |
73 | |
74 | #define WDT_TIMEOUT 60 /* 1 minute */ |
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 | * Some symbolic names |
84 | */ |
85 | |
86 | #define WDT_CTRL_REG 0x30 |
87 | #define WDT_OUTPIN_CFG 0xe2 |
88 | #define WDT_EVENT_INT 0x00 |
89 | #define WDT_EVENT_REBOOT 0x08 |
90 | #define WDT_UNIT_SEL 0xf1 |
91 | #define WDT_UNIT_SECS 0x80 |
92 | #define WDT_TIMEOUT_VAL 0xf2 |
93 | #define WDT_TIMER_CFG 0xf3 |
94 | |
95 | |
96 | module_param_hw(io, int, ioport, 0); |
97 | MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)" ); |
98 | module_param_hw(irq, int, irq, 0); |
99 | MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)" ); |
100 | module_param(ev, charp, 0); |
101 | MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')" ); |
102 | |
103 | |
104 | /* |
105 | * Programming support |
106 | */ |
107 | |
108 | static inline void eurwdt_write_reg(u8 index, u8 data) |
109 | { |
110 | outb(value: index, port: io); |
111 | outb(value: data, port: io+1); |
112 | } |
113 | |
114 | static inline void eurwdt_lock_chip(void) |
115 | { |
116 | outb(value: 0xaa, port: io); |
117 | } |
118 | |
119 | static inline void eurwdt_unlock_chip(void) |
120 | { |
121 | outb(value: 0x55, port: io); |
122 | eurwdt_write_reg(index: 0x07, data: 0x08); /* set the logical device */ |
123 | } |
124 | |
125 | static inline void eurwdt_set_timeout(int timeout) |
126 | { |
127 | eurwdt_write_reg(WDT_TIMEOUT_VAL, data: (u8) timeout); |
128 | } |
129 | |
130 | static inline void eurwdt_disable_timer(void) |
131 | { |
132 | eurwdt_set_timeout(timeout: 0); |
133 | } |
134 | |
135 | static void eurwdt_activate_timer(void) |
136 | { |
137 | eurwdt_disable_timer(); |
138 | eurwdt_write_reg(WDT_CTRL_REG, data: 0x01); /* activate the WDT */ |
139 | eurwdt_write_reg(WDT_OUTPIN_CFG, |
140 | data: !strcmp("int" , ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT); |
141 | |
142 | /* Setting interrupt line */ |
143 | if (irq == 2 || irq > 15 || irq < 0) { |
144 | pr_err("invalid irq number\n" ); |
145 | irq = 0; /* if invalid we disable interrupt */ |
146 | } |
147 | if (irq == 0) |
148 | pr_info("interrupt disabled\n" ); |
149 | |
150 | eurwdt_write_reg(WDT_TIMER_CFG, data: irq << 4); |
151 | |
152 | eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */ |
153 | eurwdt_set_timeout(timeout: 0); /* the default timeout */ |
154 | } |
155 | |
156 | |
157 | /* |
158 | * Kernel methods. |
159 | */ |
160 | |
161 | static irqreturn_t eurwdt_interrupt(int irq, void *dev_id) |
162 | { |
163 | pr_crit("timeout WDT timeout\n" ); |
164 | |
165 | #ifdef ONLY_TESTING |
166 | pr_crit("Would Reboot\n" ); |
167 | #else |
168 | pr_crit("Initiating system reboot\n" ); |
169 | emergency_restart(); |
170 | #endif |
171 | return IRQ_HANDLED; |
172 | } |
173 | |
174 | |
175 | /** |
176 | * eurwdt_ping: |
177 | * |
178 | * Reload counter one with the watchdog timeout. |
179 | */ |
180 | |
181 | static void eurwdt_ping(void) |
182 | { |
183 | /* Write the watchdog default value */ |
184 | eurwdt_set_timeout(timeout: eurwdt_timeout); |
185 | } |
186 | |
187 | /** |
188 | * eurwdt_write: |
189 | * @file: file handle to the watchdog |
190 | * @buf: buffer to write (unused as data does not matter here |
191 | * @count: count of bytes |
192 | * @ppos: pointer to the position to write. No seeks allowed |
193 | * |
194 | * A write to a watchdog device is defined as a keepalive signal. Any |
195 | * write of data will do, as we don't define content meaning. |
196 | */ |
197 | |
198 | static ssize_t eurwdt_write(struct file *file, const char __user *buf, |
199 | size_t count, loff_t *ppos) |
200 | { |
201 | if (count) { |
202 | if (!nowayout) { |
203 | size_t i; |
204 | |
205 | eur_expect_close = 0; |
206 | |
207 | for (i = 0; i != count; i++) { |
208 | char c; |
209 | if (get_user(c, buf + i)) |
210 | return -EFAULT; |
211 | if (c == 'V') |
212 | eur_expect_close = 42; |
213 | } |
214 | } |
215 | spin_lock(lock: &eurwdt_lock); |
216 | eurwdt_ping(); /* the default timeout */ |
217 | spin_unlock(lock: &eurwdt_lock); |
218 | } |
219 | return count; |
220 | } |
221 | |
222 | /** |
223 | * eurwdt_ioctl: |
224 | * @file: file handle to the device |
225 | * @cmd: watchdog command |
226 | * @arg: argument pointer |
227 | * |
228 | * The watchdog API defines a common set of functions for all watchdogs |
229 | * according to their available features. |
230 | */ |
231 | |
232 | static long eurwdt_ioctl(struct file *file, |
233 | unsigned int cmd, unsigned long arg) |
234 | { |
235 | void __user *argp = (void __user *)arg; |
236 | int __user *p = argp; |
237 | static const struct watchdog_info ident = { |
238 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
239 | | WDIOF_MAGICCLOSE, |
240 | .firmware_version = 1, |
241 | .identity = "WDT Eurotech CPU-1220/1410" , |
242 | }; |
243 | |
244 | int time; |
245 | int options, retval = -EINVAL; |
246 | |
247 | switch (cmd) { |
248 | case WDIOC_GETSUPPORT: |
249 | return copy_to_user(to: argp, from: &ident, n: sizeof(ident)) ? -EFAULT : 0; |
250 | |
251 | case WDIOC_GETSTATUS: |
252 | case WDIOC_GETBOOTSTATUS: |
253 | return put_user(0, p); |
254 | |
255 | case WDIOC_SETOPTIONS: |
256 | if (get_user(options, p)) |
257 | return -EFAULT; |
258 | spin_lock(lock: &eurwdt_lock); |
259 | if (options & WDIOS_DISABLECARD) { |
260 | eurwdt_disable_timer(); |
261 | retval = 0; |
262 | } |
263 | if (options & WDIOS_ENABLECARD) { |
264 | eurwdt_activate_timer(); |
265 | eurwdt_ping(); |
266 | retval = 0; |
267 | } |
268 | spin_unlock(lock: &eurwdt_lock); |
269 | return retval; |
270 | |
271 | case WDIOC_KEEPALIVE: |
272 | spin_lock(lock: &eurwdt_lock); |
273 | eurwdt_ping(); |
274 | spin_unlock(lock: &eurwdt_lock); |
275 | return 0; |
276 | |
277 | case WDIOC_SETTIMEOUT: |
278 | if (copy_from_user(to: &time, from: p, n: sizeof(int))) |
279 | return -EFAULT; |
280 | |
281 | /* Sanity check */ |
282 | if (time < 0 || time > 255) |
283 | return -EINVAL; |
284 | |
285 | spin_lock(lock: &eurwdt_lock); |
286 | eurwdt_timeout = time; |
287 | eurwdt_set_timeout(timeout: time); |
288 | spin_unlock(lock: &eurwdt_lock); |
289 | fallthrough; |
290 | |
291 | case WDIOC_GETTIMEOUT: |
292 | return put_user(eurwdt_timeout, p); |
293 | |
294 | default: |
295 | return -ENOTTY; |
296 | } |
297 | } |
298 | |
299 | /** |
300 | * eurwdt_open: |
301 | * @inode: inode of device |
302 | * @file: file handle to device |
303 | * |
304 | * The misc device has been opened. The watchdog device is single |
305 | * open and on opening we load the counter. |
306 | */ |
307 | |
308 | static int eurwdt_open(struct inode *inode, struct file *file) |
309 | { |
310 | if (test_and_set_bit(nr: 0, addr: &eurwdt_is_open)) |
311 | return -EBUSY; |
312 | eurwdt_timeout = WDT_TIMEOUT; /* initial timeout */ |
313 | /* Activate the WDT */ |
314 | eurwdt_activate_timer(); |
315 | return stream_open(inode, filp: file); |
316 | } |
317 | |
318 | /** |
319 | * eurwdt_release: |
320 | * @inode: inode to board |
321 | * @file: file handle to board |
322 | * |
323 | * The watchdog has a configurable API. There is a religious dispute |
324 | * between people who want their watchdog to be able to shut down and |
325 | * those who want to be sure if the watchdog manager dies the machine |
326 | * reboots. In the former case we disable the counters, in the latter |
327 | * case you have to open it again very soon. |
328 | */ |
329 | |
330 | static int eurwdt_release(struct inode *inode, struct file *file) |
331 | { |
332 | if (eur_expect_close == 42) |
333 | eurwdt_disable_timer(); |
334 | else { |
335 | pr_crit("Unexpected close, not stopping watchdog!\n" ); |
336 | eurwdt_ping(); |
337 | } |
338 | clear_bit(nr: 0, addr: &eurwdt_is_open); |
339 | eur_expect_close = 0; |
340 | return 0; |
341 | } |
342 | |
343 | /** |
344 | * eurwdt_notify_sys: |
345 | * @this: our notifier block |
346 | * @code: the event being reported |
347 | * @unused: unused |
348 | * |
349 | * Our notifier is called on system shutdowns. We want to turn the card |
350 | * off at reboot otherwise the machine will reboot again during memory |
351 | * test or worse yet during the following fsck. This would suck, in fact |
352 | * trust me - if it happens it does suck. |
353 | */ |
354 | |
355 | static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code, |
356 | void *unused) |
357 | { |
358 | if (code == SYS_DOWN || code == SYS_HALT) |
359 | eurwdt_disable_timer(); /* Turn the card off */ |
360 | |
361 | return NOTIFY_DONE; |
362 | } |
363 | |
364 | /* |
365 | * Kernel Interfaces |
366 | */ |
367 | |
368 | |
369 | static const struct file_operations eurwdt_fops = { |
370 | .owner = THIS_MODULE, |
371 | .llseek = no_llseek, |
372 | .write = eurwdt_write, |
373 | .unlocked_ioctl = eurwdt_ioctl, |
374 | .compat_ioctl = compat_ptr_ioctl, |
375 | .open = eurwdt_open, |
376 | .release = eurwdt_release, |
377 | }; |
378 | |
379 | static struct miscdevice eurwdt_miscdev = { |
380 | .minor = WATCHDOG_MINOR, |
381 | .name = "watchdog" , |
382 | .fops = &eurwdt_fops, |
383 | }; |
384 | |
385 | /* |
386 | * The WDT card needs to learn about soft shutdowns in order to |
387 | * turn the timebomb registers off. |
388 | */ |
389 | |
390 | static struct notifier_block eurwdt_notifier = { |
391 | .notifier_call = eurwdt_notify_sys, |
392 | }; |
393 | |
394 | /** |
395 | * eurwdt_exit: |
396 | * |
397 | * Unload the watchdog. You cannot do this with any file handles open. |
398 | * If your watchdog is set to continue ticking on close and you unload |
399 | * it, well it keeps ticking. We won't get the interrupt but the board |
400 | * will not touch PC memory so all is fine. You just have to load a new |
401 | * module in 60 seconds or reboot. |
402 | */ |
403 | |
404 | static void __exit eurwdt_exit(void) |
405 | { |
406 | eurwdt_lock_chip(); |
407 | |
408 | misc_deregister(misc: &eurwdt_miscdev); |
409 | |
410 | unregister_reboot_notifier(&eurwdt_notifier); |
411 | release_region(io, 2); |
412 | free_irq(irq, NULL); |
413 | } |
414 | |
415 | /** |
416 | * eurwdt_init: |
417 | * |
418 | * Set up the WDT watchdog board. After grabbing the resources |
419 | * we require we need also to unlock the device. |
420 | * The open() function will actually kick the board off. |
421 | */ |
422 | |
423 | static int __init eurwdt_init(void) |
424 | { |
425 | int ret; |
426 | |
427 | ret = request_irq(irq, handler: eurwdt_interrupt, flags: 0, name: "eurwdt" , NULL); |
428 | if (ret) { |
429 | pr_err("IRQ %d is not free\n" , irq); |
430 | goto out; |
431 | } |
432 | |
433 | if (!request_region(io, 2, "eurwdt" )) { |
434 | pr_err("IO %X is not free\n" , io); |
435 | ret = -EBUSY; |
436 | goto outirq; |
437 | } |
438 | |
439 | ret = register_reboot_notifier(&eurwdt_notifier); |
440 | if (ret) { |
441 | pr_err("can't register reboot notifier (err=%d)\n" , ret); |
442 | goto outreg; |
443 | } |
444 | |
445 | ret = misc_register(misc: &eurwdt_miscdev); |
446 | if (ret) { |
447 | pr_err("can't misc_register on minor=%d\n" , WATCHDOG_MINOR); |
448 | goto outreboot; |
449 | } |
450 | |
451 | eurwdt_unlock_chip(); |
452 | |
453 | ret = 0; |
454 | pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n" , |
455 | io, irq, (!strcmp("int" , ev) ? "int" : "reboot" )); |
456 | |
457 | out: |
458 | return ret; |
459 | |
460 | outreboot: |
461 | unregister_reboot_notifier(&eurwdt_notifier); |
462 | |
463 | outreg: |
464 | release_region(io, 2); |
465 | |
466 | outirq: |
467 | free_irq(irq, NULL); |
468 | goto out; |
469 | } |
470 | |
471 | module_init(eurwdt_init); |
472 | module_exit(eurwdt_exit); |
473 | |
474 | MODULE_AUTHOR("Rodolfo Giometti" ); |
475 | MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog" ); |
476 | MODULE_LICENSE("GPL" ); |
477 | |