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
eurwdt_write_reg(u8 index,u8 data)108 static inline void eurwdt_write_reg(u8 index, u8 data)
109 {
110 outb(index, io);
111 outb(data, io+1);
112 }
113
eurwdt_lock_chip(void)114 static inline void eurwdt_lock_chip(void)
115 {
116 outb(0xaa, io);
117 }
118
eurwdt_unlock_chip(void)119 static inline void eurwdt_unlock_chip(void)
120 {
121 outb(0x55, io);
122 eurwdt_write_reg(0x07, 0x08); /* set the logical device */
123 }
124
eurwdt_set_timeout(int timeout)125 static inline void eurwdt_set_timeout(int timeout)
126 {
127 eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
128 }
129
eurwdt_disable_timer(void)130 static inline void eurwdt_disable_timer(void)
131 {
132 eurwdt_set_timeout(0);
133 }
134
eurwdt_activate_timer(void)135 static void eurwdt_activate_timer(void)
136 {
137 eurwdt_disable_timer();
138 eurwdt_write_reg(WDT_CTRL_REG, 0x01); /* activate the WDT */
139 eurwdt_write_reg(WDT_OUTPIN_CFG,
140 !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, irq << 4);
151
152 eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */
153 eurwdt_set_timeout(0); /* the default timeout */
154 }
155
156
157 /*
158 * Kernel methods.
159 */
160
eurwdt_interrupt(int irq,void * dev_id)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
eurwdt_ping(void)181 static void eurwdt_ping(void)
182 {
183 /* Write the watchdog default value */
184 eurwdt_set_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 we don't define content meaning.
196 */
197
eurwdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)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(&eurwdt_lock);
216 eurwdt_ping(); /* the default timeout */
217 spin_unlock(&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
eurwdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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(argp, &ident, 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(&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(&eurwdt_lock);
269 return retval;
270
271 case WDIOC_KEEPALIVE:
272 spin_lock(&eurwdt_lock);
273 eurwdt_ping();
274 spin_unlock(&eurwdt_lock);
275 return 0;
276
277 case WDIOC_SETTIMEOUT:
278 if (copy_from_user(&time, p, sizeof(int)))
279 return -EFAULT;
280
281 /* Sanity check */
282 if (time < 0 || time > 255)
283 return -EINVAL;
284
285 spin_lock(&eurwdt_lock);
286 eurwdt_timeout = time;
287 eurwdt_set_timeout(time);
288 spin_unlock(&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
eurwdt_open(struct inode * inode,struct file * file)308 static int eurwdt_open(struct inode *inode, struct file *file)
309 {
310 if (test_and_set_bit(0, &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, 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
eurwdt_release(struct inode * inode,struct file * file)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(0, &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
eurwdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)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 * cleanup_module:
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
eurwdt_exit(void)404 static void __exit eurwdt_exit(void)
405 {
406 eurwdt_lock_chip();
407
408 misc_deregister(&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
eurwdt_init(void)423 static int __init eurwdt_init(void)
424 {
425 int ret;
426
427 ret = request_irq(irq, eurwdt_interrupt, 0, "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(&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
