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 
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 
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 
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 
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 
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 
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 */
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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(io, int, 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