1 /*
2 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
3 *
4 * This code is based on wdt.c with original copyright.
5 *
6 * (C) Copyright 2006 Sven Anders, <anders@anduras.de>
7 * and Marcus Junker, <junker@anduras.de>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 *
14 * Neither Sven Anders, Marcus Junker nor ANDURAS AG
15 * admit liability nor provide warranty for any of this software.
16 * This material is provided "AS-IS" and at no charge.
17 *
18 * Release 1.1
19 */
20
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/ioport.h>
28 #include <linux/delay.h>
29 #include <linux/notifier.h>
30 #include <linux/fs.h>
31 #include <linux/reboot.h>
32 #include <linux/init.h>
33 #include <linux/spinlock.h>
34 #include <linux/moduleparam.h>
35 #include <linux/io.h>
36 #include <linux/uaccess.h>
37
38
39 /* #define DEBUG 1 */
40
41 #define DEFAULT_TIMEOUT 1 /* 1 minute */
42 #define MAX_TIMEOUT 255
43
44 #define VERSION "1.1"
45 #define MODNAME "pc87413 WDT"
46 #define DPFX MODNAME " - DEBUG: "
47
48 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */
49 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1)
50 #define SWC_LDN 0x04
51 #define SIOCFG2 0x22 /* Serial IO register */
52 #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */
53 #define WDTO 0x11 /* Watchdog timeout register */
54 #define WDCFG 0x12 /* Watchdog config register */
55
56 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
57
58 static int io = IO_DEFAULT;
59 static int swc_base_addr = -1;
60
61 static int timeout = DEFAULT_TIMEOUT; /* timeout value */
62 static unsigned long timer_enabled; /* is the timer enabled? */
63
64 static char expect_close; /* is the close expected? */
65
66 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */
67
68 static bool nowayout = WATCHDOG_NOWAYOUT;
69
70 /* -- Low level function ----------------------------------------*/
71
72 /* Select pins for Watchdog output */
73
pc87413_select_wdt_out(void)74 static inline void pc87413_select_wdt_out(void)
75 {
76 unsigned int cr_data = 0;
77
78 /* Step 1: Select multiple pin,pin55,as WDT output */
79
80 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
81
82 cr_data = inb(WDT_DATA_IO_PORT);
83
84 cr_data |= 0x80; /* Set Bit7 to 1*/
85 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
86
87 outb_p(cr_data, WDT_DATA_IO_PORT);
88
89 #ifdef DEBUG
90 pr_info(DPFX
91 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
92 cr_data);
93 #endif
94 }
95
96 /* Enable SWC functions */
97
pc87413_enable_swc(void)98 static inline void pc87413_enable_swc(void)
99 {
100 unsigned int cr_data = 0;
101
102 /* Step 2: Enable SWC functions */
103
104 outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */
105 outb_p(SWC_LDN, WDT_DATA_IO_PORT);
106
107 outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */
108 cr_data = inb(WDT_DATA_IO_PORT);
109 cr_data |= 0x01; /* Set Bit0 to 1 */
110 outb_p(0x30, WDT_INDEX_IO_PORT);
111 outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */
112
113 #ifdef DEBUG
114 pr_info(DPFX "pc87413 - Enable SWC functions\n");
115 #endif
116 }
117
118 /* Read SWC I/O base address */
119
pc87413_get_swc_base_addr(void)120 static void pc87413_get_swc_base_addr(void)
121 {
122 unsigned char addr_l, addr_h = 0;
123
124 /* Step 3: Read SWC I/O Base Address */
125
126 outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */
127 addr_h = inb(WDT_DATA_IO_PORT);
128
129 outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */
130
131 addr_l = inb(WDT_DATA_IO_PORT);
132
133 swc_base_addr = (addr_h << 8) + addr_l;
134 #ifdef DEBUG
135 pr_info(DPFX
136 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
137 addr_l, addr_h, swc_base_addr);
138 #endif
139 }
140
141 /* Select Bank 3 of SWC */
142
pc87413_swc_bank3(void)143 static inline void pc87413_swc_bank3(void)
144 {
145 /* Step 4: Select Bank3 of SWC */
146 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
147 #ifdef DEBUG
148 pr_info(DPFX "Select Bank3 of SWC\n");
149 #endif
150 }
151
152 /* Set watchdog timeout to x minutes */
153
pc87413_programm_wdto(char pc87413_time)154 static inline void pc87413_programm_wdto(char pc87413_time)
155 {
156 /* Step 5: Programm WDTO, Twd. */
157 outb_p(pc87413_time, swc_base_addr + WDTO);
158 #ifdef DEBUG
159 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
160 #endif
161 }
162
163 /* Enable WDEN */
164
pc87413_enable_wden(void)165 static inline void pc87413_enable_wden(void)
166 {
167 /* Step 6: Enable WDEN */
168 outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
169 #ifdef DEBUG
170 pr_info(DPFX "Enable WDEN\n");
171 #endif
172 }
173
174 /* Enable SW_WD_TREN */
pc87413_enable_sw_wd_tren(void)175 static inline void pc87413_enable_sw_wd_tren(void)
176 {
177 /* Enable SW_WD_TREN */
178 outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
179 #ifdef DEBUG
180 pr_info(DPFX "Enable SW_WD_TREN\n");
181 #endif
182 }
183
184 /* Disable SW_WD_TREN */
185
pc87413_disable_sw_wd_tren(void)186 static inline void pc87413_disable_sw_wd_tren(void)
187 {
188 /* Disable SW_WD_TREN */
189 outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
190 #ifdef DEBUG
191 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
192 #endif
193 }
194
195 /* Enable SW_WD_TRG */
196
pc87413_enable_sw_wd_trg(void)197 static inline void pc87413_enable_sw_wd_trg(void)
198 {
199 /* Enable SW_WD_TRG */
200 outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
201 #ifdef DEBUG
202 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
203 #endif
204 }
205
206 /* Disable SW_WD_TRG */
207
pc87413_disable_sw_wd_trg(void)208 static inline void pc87413_disable_sw_wd_trg(void)
209 {
210 /* Disable SW_WD_TRG */
211 outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
212 #ifdef DEBUG
213 pr_info(DPFX "Disable SW_WD_TRG\n");
214 #endif
215 }
216
217 /* -- Higher level functions ------------------------------------*/
218
219 /* Enable the watchdog */
220
pc87413_enable(void)221 static void pc87413_enable(void)
222 {
223 spin_lock(&io_lock);
224
225 pc87413_swc_bank3();
226 pc87413_programm_wdto(timeout);
227 pc87413_enable_wden();
228 pc87413_enable_sw_wd_tren();
229 pc87413_enable_sw_wd_trg();
230
231 spin_unlock(&io_lock);
232 }
233
234 /* Disable the watchdog */
235
pc87413_disable(void)236 static void pc87413_disable(void)
237 {
238 spin_lock(&io_lock);
239
240 pc87413_swc_bank3();
241 pc87413_disable_sw_wd_tren();
242 pc87413_disable_sw_wd_trg();
243 pc87413_programm_wdto(0);
244
245 spin_unlock(&io_lock);
246 }
247
248 /* Refresh the watchdog */
249
pc87413_refresh(void)250 static void pc87413_refresh(void)
251 {
252 spin_lock(&io_lock);
253
254 pc87413_swc_bank3();
255 pc87413_disable_sw_wd_tren();
256 pc87413_disable_sw_wd_trg();
257 pc87413_programm_wdto(timeout);
258 pc87413_enable_wden();
259 pc87413_enable_sw_wd_tren();
260 pc87413_enable_sw_wd_trg();
261
262 spin_unlock(&io_lock);
263 }
264
265 /* -- File operations -------------------------------------------*/
266
267 /**
268 * pc87413_open:
269 * @inode: inode of device
270 * @file: file handle to device
271 *
272 */
273
pc87413_open(struct inode * inode,struct file * file)274 static int pc87413_open(struct inode *inode, struct file *file)
275 {
276 /* /dev/watchdog can only be opened once */
277
278 if (test_and_set_bit(0, &timer_enabled))
279 return -EBUSY;
280
281 if (nowayout)
282 __module_get(THIS_MODULE);
283
284 /* Reload and activate timer */
285 pc87413_refresh();
286
287 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
288
289 return nonseekable_open(inode, file);
290 }
291
292 /**
293 * pc87413_release:
294 * @inode: inode to board
295 * @file: file handle to board
296 *
297 * The watchdog has a configurable API. There is a religious dispute
298 * between people who want their watchdog to be able to shut down and
299 * those who want to be sure if the watchdog manager dies the machine
300 * reboots. In the former case we disable the counters, in the latter
301 * case you have to open it again very soon.
302 */
303
pc87413_release(struct inode * inode,struct file * file)304 static int pc87413_release(struct inode *inode, struct file *file)
305 {
306 /* Shut off the timer. */
307
308 if (expect_close == 42) {
309 pc87413_disable();
310 pr_info("Watchdog disabled, sleeping again...\n");
311 } else {
312 pr_crit("Unexpected close, not stopping watchdog!\n");
313 pc87413_refresh();
314 }
315 clear_bit(0, &timer_enabled);
316 expect_close = 0;
317 return 0;
318 }
319
320 /**
321 * pc87413_status:
322 *
323 * return, if the watchdog is enabled (timeout is set...)
324 */
325
326
pc87413_status(void)327 static int pc87413_status(void)
328 {
329 return 0; /* currently not supported */
330 }
331
332 /**
333 * pc87413_write:
334 * @file: file handle to the watchdog
335 * @data: data buffer to write
336 * @len: length in bytes
337 * @ppos: pointer to the position to write. No seeks allowed
338 *
339 * A write to a watchdog device is defined as a keepalive signal. Any
340 * write of data will do, as we we don't define content meaning.
341 */
342
pc87413_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)343 static ssize_t pc87413_write(struct file *file, const char __user *data,
344 size_t len, loff_t *ppos)
345 {
346 /* See if we got the magic character 'V' and reload the timer */
347 if (len) {
348 if (!nowayout) {
349 size_t i;
350
351 /* reset expect flag */
352 expect_close = 0;
353
354 /* scan to see whether or not we got the
355 magic character */
356 for (i = 0; i != len; i++) {
357 char c;
358 if (get_user(c, data + i))
359 return -EFAULT;
360 if (c == 'V')
361 expect_close = 42;
362 }
363 }
364
365 /* someone wrote to us, we should reload the timer */
366 pc87413_refresh();
367 }
368 return len;
369 }
370
371 /**
372 * pc87413_ioctl:
373 * @file: file handle to the device
374 * @cmd: watchdog command
375 * @arg: argument pointer
376 *
377 * The watchdog API defines a common set of functions for all watchdogs
378 * according to their available features. We only actually usefully support
379 * querying capabilities and current status.
380 */
381
pc87413_ioctl(struct file * file,unsigned int cmd,unsigned long arg)382 static long pc87413_ioctl(struct file *file, unsigned int cmd,
383 unsigned long arg)
384 {
385 int new_timeout;
386
387 union {
388 struct watchdog_info __user *ident;
389 int __user *i;
390 } uarg;
391
392 static const struct watchdog_info ident = {
393 .options = WDIOF_KEEPALIVEPING |
394 WDIOF_SETTIMEOUT |
395 WDIOF_MAGICCLOSE,
396 .firmware_version = 1,
397 .identity = "PC87413(HF/F) watchdog",
398 };
399
400 uarg.i = (int __user *)arg;
401
402 switch (cmd) {
403 case WDIOC_GETSUPPORT:
404 return copy_to_user(uarg.ident, &ident,
405 sizeof(ident)) ? -EFAULT : 0;
406 case WDIOC_GETSTATUS:
407 return put_user(pc87413_status(), uarg.i);
408 case WDIOC_GETBOOTSTATUS:
409 return put_user(0, uarg.i);
410 case WDIOC_SETOPTIONS:
411 {
412 int options, retval = -EINVAL;
413 if (get_user(options, uarg.i))
414 return -EFAULT;
415 if (options & WDIOS_DISABLECARD) {
416 pc87413_disable();
417 retval = 0;
418 }
419 if (options & WDIOS_ENABLECARD) {
420 pc87413_enable();
421 retval = 0;
422 }
423 return retval;
424 }
425 case WDIOC_KEEPALIVE:
426 pc87413_refresh();
427 #ifdef DEBUG
428 pr_info(DPFX "keepalive\n");
429 #endif
430 return 0;
431 case WDIOC_SETTIMEOUT:
432 if (get_user(new_timeout, uarg.i))
433 return -EFAULT;
434 /* the API states this is given in secs */
435 new_timeout /= 60;
436 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
437 return -EINVAL;
438 timeout = new_timeout;
439 pc87413_refresh();
440 /* fall through and return the new timeout... */
441 case WDIOC_GETTIMEOUT:
442 new_timeout = timeout * 60;
443 return put_user(new_timeout, uarg.i);
444 default:
445 return -ENOTTY;
446 }
447 }
448
449 /* -- Notifier funtions -----------------------------------------*/
450
451 /**
452 * notify_sys:
453 * @this: our notifier block
454 * @code: the event being reported
455 * @unused: unused
456 *
457 * Our notifier is called on system shutdowns. We want to turn the card
458 * off at reboot otherwise the machine will reboot again during memory
459 * test or worse yet during the following fsck. This would suck, in fact
460 * trust me - if it happens it does suck.
461 */
462
pc87413_notify_sys(struct notifier_block * this,unsigned long code,void * unused)463 static int pc87413_notify_sys(struct notifier_block *this,
464 unsigned long code,
465 void *unused)
466 {
467 if (code == SYS_DOWN || code == SYS_HALT)
468 /* Turn the card off */
469 pc87413_disable();
470 return NOTIFY_DONE;
471 }
472
473 /* -- Module's structures ---------------------------------------*/
474
475 static const struct file_operations pc87413_fops = {
476 .owner = THIS_MODULE,
477 .llseek = no_llseek,
478 .write = pc87413_write,
479 .unlocked_ioctl = pc87413_ioctl,
480 .open = pc87413_open,
481 .release = pc87413_release,
482 };
483
484 static struct notifier_block pc87413_notifier = {
485 .notifier_call = pc87413_notify_sys,
486 };
487
488 static struct miscdevice pc87413_miscdev = {
489 .minor = WATCHDOG_MINOR,
490 .name = "watchdog",
491 .fops = &pc87413_fops,
492 };
493
494 /* -- Module init functions -------------------------------------*/
495
496 /**
497 * pc87413_init: module's "constructor"
498 *
499 * Set up the WDT watchdog board. All we have to do is grab the
500 * resources we require and bitch if anyone beat us to them.
501 * The open() function will actually kick the board off.
502 */
503
pc87413_init(void)504 static int __init pc87413_init(void)
505 {
506 int ret;
507
508 pr_info("Version " VERSION " at io 0x%X\n",
509 WDT_INDEX_IO_PORT);
510
511 if (!request_muxed_region(io, 2, MODNAME))
512 return -EBUSY;
513
514 ret = register_reboot_notifier(&pc87413_notifier);
515 if (ret != 0)
516 pr_err("cannot register reboot notifier (err=%d)\n", ret);
517
518 ret = misc_register(&pc87413_miscdev);
519 if (ret != 0) {
520 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
521 WATCHDOG_MINOR, ret);
522 goto reboot_unreg;
523 }
524 pr_info("initialized. timeout=%d min\n", timeout);
525
526 pc87413_select_wdt_out();
527 pc87413_enable_swc();
528 pc87413_get_swc_base_addr();
529
530 if (!request_region(swc_base_addr, 0x20, MODNAME)) {
531 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
532 ret = -EBUSY;
533 goto misc_unreg;
534 }
535
536 pc87413_enable();
537
538 release_region(io, 2);
539 return 0;
540
541 misc_unreg:
542 misc_deregister(&pc87413_miscdev);
543 reboot_unreg:
544 unregister_reboot_notifier(&pc87413_notifier);
545 release_region(io, 2);
546 return ret;
547 }
548
549 /**
550 * pc87413_exit: module's "destructor"
551 *
552 * Unload the watchdog. You cannot do this with any file handles open.
553 * If your watchdog is set to continue ticking on close and you unload
554 * it, well it keeps ticking. We won't get the interrupt but the board
555 * will not touch PC memory so all is fine. You just have to load a new
556 * module in 60 seconds or reboot.
557 */
558
pc87413_exit(void)559 static void __exit pc87413_exit(void)
560 {
561 /* Stop the timer before we leave */
562 if (!nowayout) {
563 pc87413_disable();
564 pr_info("Watchdog disabled\n");
565 }
566
567 misc_deregister(&pc87413_miscdev);
568 unregister_reboot_notifier(&pc87413_notifier);
569 release_region(swc_base_addr, 0x20);
570
571 pr_info("watchdog component driver removed\n");
572 }
573
574 module_init(pc87413_init);
575 module_exit(pc87413_exit);
576
577 MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
578 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
579 MODULE_DESCRIPTION("PC87413 WDT driver");
580 MODULE_LICENSE("GPL");
581
582 module_param_hw(io, int, ioport, 0);
583 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
584 __MODULE_STRING(IO_DEFAULT) ").");
585
586 module_param(timeout, int, 0);
587 MODULE_PARM_DESC(timeout,
588 "Watchdog timeout in minutes (default="
589 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
590
591 module_param(nowayout, bool, 0);
592 MODULE_PARM_DESC(nowayout,
593 "Watchdog cannot be stopped once started (default="
594 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
595
596
