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#include <linux/module.h>
22#include <linux/types.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/ioport.h>
26#include <linux/delay.h>
27#include <linux/notifier.h>
28#include <linux/fs.h>
29#include <linux/reboot.h>
30#include <linux/init.h>
31#include <linux/spinlock.h>
32#include <linux/moduleparam.h>
33#include <linux/version.h>
34
35#include <asm/io.h>
36#include <asm/uaccess.h>
37#include <asm/system.h>
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 PFX                 MODNAME ": "
47#define DPFX                MODNAME " - DEBUG: "
48
49#define WDT_INDEX_IO_PORT   (io+0)       /* I/O port base (index register) */
50#define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
51#define SWC_LDN             0x04
52#define SIOCFG2             0x22         /* Serial IO register */
53#define WDCTL               0x10         /* Watchdog-Timer-Controll-Register */
54#define WDTO                0x11         /* Watchdog timeout register */
55#define WDCFG               0x12         /* Watchdog config register */
56
57static int io = 0x2E;		         /* Address used on Portwell Boards */
58
59static int timeout = DEFAULT_TIMEOUT;    /* timeout value */
60static unsigned long timer_enabled = 0;  /* is the timer enabled? */
61
62static char expect_close;                /* is the close expected? */
63
64static spinlock_t io_lock;               /* to guard the watchdog from io races */
65
66static int nowayout = WATCHDOG_NOWAYOUT;
67
68/* -- Low level function ----------------------------------------*/
69
70/* Select pins for Watchdog output */
71
72static inline void pc87413_select_wdt_out (void)
73{
74	unsigned int cr_data = 0;
75
76	/* Step 1: Select multiple pin,pin55,as WDT output */
77
78	outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
79
80	cr_data = inb (WDT_DATA_IO_PORT);
81
82	cr_data |= 0x80; /* Set Bit7 to 1*/
83	outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
84
85	outb_p(cr_data, WDT_DATA_IO_PORT);
86
87#ifdef DEBUG
88	printk(KERN_INFO DPFX "Select multiple pin,pin55,as WDT output:"
89	                      " Bit7 to 1: %d\n", cr_data);
90#endif
91}
92
93/* Enable SWC functions */
94
95static inline void pc87413_enable_swc(void)
96{
97	unsigned int cr_data=0;
98
99	/* Step 2: Enable SWC functions */
100
101	outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
102	outb_p(SWC_LDN, WDT_DATA_IO_PORT);
103
104	outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
105	cr_data = inb(WDT_DATA_IO_PORT);
106	cr_data |= 0x01;                        /* Set Bit0 to 1 */
107	outb_p(0x30, WDT_INDEX_IO_PORT);
108	outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
109
110#ifdef DEBUG
111	printk(KERN_INFO DPFX "pc87413 - Enable SWC functions\n");
112#endif
113}
114
115/* Read SWC I/O base address */
116
117static inline unsigned int pc87413_get_swc_base(void)
118{
119	unsigned int  swc_base_addr = 0;
120	unsigned char addr_l, addr_h = 0;
121
122	/* Step 3: Read SWC I/O Base Address */
123
124	outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
125	addr_h = inb(WDT_DATA_IO_PORT);
126
127	outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */
128
129	addr_l = inb(WDT_DATA_IO_PORT);
130
131	swc_base_addr = (addr_h << 8) + addr_l;
132
133#ifdef DEBUG
134	printk(KERN_INFO DPFX "Read SWC I/O Base Address: low %d, high %d,"
135	                      " res %d\n", addr_l, addr_h, swc_base_addr);
136#endif
137
138	return swc_base_addr;
139}
140
141/* Select Bank 3 of SWC */
142
143static inline void pc87413_swc_bank3(unsigned int swc_base_addr)
144{
145	/* Step 4: Select Bank3 of SWC */
146
147	outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
148
149#ifdef DEBUG
150	printk(KERN_INFO DPFX "Select Bank3 of SWC\n");
151#endif
152}
153
154/* Set watchdog timeout to x minutes */
155
156static inline void pc87413_programm_wdto(unsigned int swc_base_addr,
157					 char pc87413_time)
158{
159	/* Step 5: Programm WDTO, Twd. */
160
161	outb_p(pc87413_time, swc_base_addr + WDTO);
162
163#ifdef DEBUG
164	printk(KERN_INFO DPFX "Set WDTO to %d minutes\n", pc87413_time);
165#endif
166}
167
168/* Enable WDEN */
169
170static inline void pc87413_enable_wden(unsigned int swc_base_addr)
171{
172	/* Step 6: Enable WDEN */
173
174	outb_p(inb (swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
175
176#ifdef DEBUG
177	printk(KERN_INFO DPFX "Enable WDEN\n");
178#endif
179}
180
181/* Enable SW_WD_TREN */
182static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr)
183{
184	/* Enable SW_WD_TREN */
185
186	outb_p(inb (swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
187
188#ifdef DEBUG
189	printk(KERN_INFO DPFX "Enable SW_WD_TREN\n");
190#endif
191}
192
193/* Disable SW_WD_TREN */
194
195static inline void pc87413_disable_sw_wd_tren(unsigned int swc_base_addr)
196{
197	/* Disable SW_WD_TREN */
198
199	outb_p(inb (swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
200
201#ifdef DEBUG
202	printk(KERN_INFO DPFX "pc87413 - Disable SW_WD_TREN\n");
203#endif
204}
205
206/* Enable SW_WD_TRG */
207
208static inline void pc87413_enable_sw_wd_trg(unsigned int swc_base_addr)
209{
210	/* Enable SW_WD_TRG */
211
212	outb_p(inb (swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
213
214#ifdef DEBUG
215	printk(KERN_INFO DPFX "pc87413 - Enable SW_WD_TRG\n");
216#endif
217}
218
219/* Disable SW_WD_TRG */
220
221static inline void pc87413_disable_sw_wd_trg(unsigned int swc_base_addr)
222{
223	/* Disable SW_WD_TRG */
224
225	outb_p(inb (swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
226
227#ifdef DEBUG
228	printk(KERN_INFO DPFX "Disable SW_WD_TRG\n");
229#endif
230}
231
232/* -- Higher level functions ------------------------------------*/
233
234/* Enable the watchdog */
235
236static void pc87413_enable(void)
237{
238	unsigned int swc_base_addr;
239
240	spin_lock(&io_lock);
241
242	pc87413_select_wdt_out();
243	pc87413_enable_swc();
244	swc_base_addr = pc87413_get_swc_base();
245	pc87413_swc_bank3(swc_base_addr);
246	pc87413_programm_wdto(swc_base_addr, timeout);
247	pc87413_enable_wden(swc_base_addr);
248	pc87413_enable_sw_wd_tren(swc_base_addr);
249	pc87413_enable_sw_wd_trg(swc_base_addr);
250
251	spin_unlock(&io_lock);
252}
253
254/* Disable the watchdog */
255
256static void pc87413_disable(void)
257{
258	unsigned int swc_base_addr;
259
260	spin_lock(&io_lock);
261
262	pc87413_select_wdt_out();
263	pc87413_enable_swc();
264	swc_base_addr = pc87413_get_swc_base();
265	pc87413_swc_bank3(swc_base_addr);
266	pc87413_disable_sw_wd_tren(swc_base_addr);
267	pc87413_disable_sw_wd_trg(swc_base_addr);
268	pc87413_programm_wdto(swc_base_addr, 0);
269
270	spin_unlock(&io_lock);
271}
272
273/* Refresh the watchdog */
274
275static void pc87413_refresh(void)
276{
277	unsigned int swc_base_addr;
278
279	spin_lock(&io_lock);
280
281	pc87413_select_wdt_out();
282	pc87413_enable_swc();
283	swc_base_addr = pc87413_get_swc_base();
284	pc87413_swc_bank3(swc_base_addr);
285	pc87413_disable_sw_wd_tren(swc_base_addr);
286	pc87413_disable_sw_wd_trg(swc_base_addr);
287	pc87413_programm_wdto(swc_base_addr, timeout);
288	pc87413_enable_wden(swc_base_addr);
289	pc87413_enable_sw_wd_tren(swc_base_addr);
290	pc87413_enable_sw_wd_trg(swc_base_addr);
291
292	spin_unlock(&io_lock);
293}
294
295/* -- File operations -------------------------------------------*/
296
297/**
298 *	pc87413_open:
299 *	@inode: inode of device
300 *	@file: file handle to device
301 *
302 */
303
304static int pc87413_open(struct inode *inode, struct file *file)
305{
306	/* /dev/watchdog can only be opened once */
307
308	if (test_and_set_bit(0, &timer_enabled))
309		return -EBUSY;
310
311	if (nowayout)
312		__module_get(THIS_MODULE);
313
314	/* Reload and activate timer */
315	pc87413_refresh();
316
317	printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to"
318	                         " %d minute(s).\n", timeout);
319
320	return nonseekable_open(inode, file);
321}
322
323/**
324 *	pc87413_release:
325 *	@inode: inode to board
326 *	@file: file handle to board
327 *
328 *	The watchdog has a configurable API. There is a religious dispute
329 *	between people who want their watchdog to be able to shut down and
330 *	those who want to be sure if the watchdog manager dies the machine
331 *	reboots. In the former case we disable the counters, in the latter
332 *	case you have to open it again very soon.
333 */
334
335static int pc87413_release(struct inode *inode, struct file *file)
336{
337	/* Shut off the timer. */
338
339	if (expect_close == 42) {
340		pc87413_disable();
341		printk(KERN_INFO MODNAME "Watchdog disabled,"
342		                         " sleeping again...\n");
343	} else {
344		printk(KERN_CRIT MODNAME "Unexpected close, not stopping"
345		                         " watchdog!\n");
346		pc87413_refresh();
347	}
348
349	clear_bit(0, &timer_enabled);
350	expect_close = 0;
351
352	return 0;
353}
354
355/**
356 *	pc87413_status:
357 *
358 *      return, if the watchdog is enabled (timeout is set...)
359 */
360
361
362static int pc87413_status(void)
363{
364	  return 0; /* currently not supported */
365}
366
367/**
368 *	pc87413_write:
369 *	@file: file handle to the watchdog
370 *	@data: data buffer to write
371 *	@len: length in bytes
372 *	@ppos: pointer to the position to write. No seeks allowed
373 *
374 *	A write to a watchdog device is defined as a keepalive signal. Any
375 *	write of data will do, as we we don't define content meaning.
376 */
377
378static ssize_t pc87413_write(struct file *file, const char __user *data,
379			     size_t len, loff_t *ppos)
380{
381	/* See if we got the magic character 'V' and reload the timer */
382	if (len) {
383		if (!nowayout) {
384			size_t i;
385
386			/* reset expect flag */
387			expect_close = 0;
388
389			/* scan to see whether or not we got the magic character */
390			for (i = 0; i != len; i++) {
391				char c;
392				if (get_user(c, data+i))
393					return -EFAULT;
394				if (c == 'V')
395					expect_close = 42;
396			}
397		}
398
399		/* someone wrote to us, we should reload the timer */
400		pc87413_refresh();
401	}
402	return len;
403}
404
405/**
406 *	pc87413_ioctl:
407 *	@inode: inode of the device
408 *	@file: file handle to the device
409 *	@cmd: watchdog command
410 *	@arg: argument pointer
411 *
412 *	The watchdog API defines a common set of functions for all watchdogs
413 *	according to their available features. We only actually usefully support
414 *	querying capabilities and current status.
415 */
416
417static int pc87413_ioctl(struct inode *inode, struct file *file,
418			 unsigned int cmd, unsigned long arg)
419{
420	int new_timeout;
421
422	union {
423		struct watchdog_info __user *ident;
424		int __user *i;
425	} uarg;
426
427	static struct watchdog_info ident = {
428		.options          = WDIOF_KEEPALIVEPING |
429		                    WDIOF_SETTIMEOUT |
430		                    WDIOF_MAGICCLOSE,
431		.firmware_version = 1,
432		.identity         = "PC87413(HF/F) watchdog"
433	};
434
435	uarg.i = (int __user *)arg;
436
437	switch(cmd) {
438		default:
439			return -ENOTTY;
440
441		case WDIOC_GETSUPPORT:
442			return copy_to_user(uarg.ident, &ident,
443				sizeof(ident)) ? -EFAULT : 0;
444
445		case WDIOC_GETSTATUS:
446			return put_user(pc87413_status(), uarg.i);
447
448		case WDIOC_GETBOOTSTATUS:
449			return put_user(0, uarg.i);
450
451		case WDIOC_KEEPALIVE:
452			pc87413_refresh();
453#ifdef DEBUG
454	                printk(KERN_INFO DPFX "keepalive\n");
455#endif
456			return 0;
457
458		case WDIOC_SETTIMEOUT:
459			if (get_user(new_timeout, uarg.i))
460				return -EFAULT;
461
462			// the API states this is given in secs
463			new_timeout /= 60;
464
465			if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
466				return -EINVAL;
467
468			timeout = new_timeout;
469			pc87413_refresh();
470
471			// fall through and return the new timeout...
472
473		case WDIOC_GETTIMEOUT:
474
475		        new_timeout = timeout * 60;
476
477			return put_user(new_timeout, uarg.i);
478
479		case WDIOC_SETOPTIONS:
480		{
481			int options, retval = -EINVAL;
482
483			if (get_user(options, uarg.i))
484				return -EFAULT;
485
486			if (options & WDIOS_DISABLECARD) {
487			        pc87413_disable();
488				retval = 0;
489			}
490
491			if (options & WDIOS_ENABLECARD) {
492				pc87413_enable();
493				retval = 0;
494			}
495
496			return retval;
497		}
498	}
499}
500
501/* -- Notifier funtions -----------------------------------------*/
502
503/**
504 *	notify_sys:
505 *	@this: our notifier block
506 *	@code: the event being reported
507 *	@unused: unused
508 *
509 *	Our notifier is called on system shutdowns. We want to turn the card
510 *	off at reboot otherwise the machine will reboot again during memory
511 *	test or worse yet during the following fsck. This would suck, in fact
512 *	trust me - if it happens it does suck.
513 */
514
515static int pc87413_notify_sys(struct notifier_block *this,
516			      unsigned long code,
517			      void *unused)
518{
519	if (code == SYS_DOWN || code == SYS_HALT)
520	{
521		/* Turn the card off */
522		pc87413_disable();
523	}
524	return NOTIFY_DONE;
525}
526
527/* -- Module's structures ---------------------------------------*/
528
529static const struct file_operations pc87413_fops = {
530	.owner		= THIS_MODULE,
531	.llseek		= no_llseek,
532	.write		= pc87413_write,
533	.ioctl		= pc87413_ioctl,
534	.open		= pc87413_open,
535	.release	= pc87413_release,
536};
537
538static struct notifier_block pc87413_notifier =
539{
540	.notifier_call  = pc87413_notify_sys,
541};
542
543static struct miscdevice pc87413_miscdev=
544{
545	.minor          = WATCHDOG_MINOR,
546	.name           = "watchdog",
547	.fops           = &pc87413_fops
548};
549
550/* -- Module init functions -------------------------------------*/
551
552/**
553 * 	pc87413_init: module's "constructor"
554 *
555 *	Set up the WDT watchdog board. All we have to do is grab the
556 *	resources we require and bitch if anyone beat us to them.
557 *	The open() function will actually kick the board off.
558 */
559
560static int __init pc87413_init(void)
561{
562	int ret;
563
564	spin_lock_init(&io_lock);
565
566	printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n", WDT_INDEX_IO_PORT);
567
568	/* request_region(io, 2, "pc87413"); */
569
570	ret = register_reboot_notifier(&pc87413_notifier);
571	if (ret != 0) {
572		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
573			ret);
574	}
575
576	ret = misc_register(&pc87413_miscdev);
577
578	if (ret != 0) {
579		printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
580			WATCHDOG_MINOR, ret);
581		unregister_reboot_notifier(&pc87413_notifier);
582		return ret;
583	}
584
585	printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout);
586
587	pc87413_enable();
588
589	return 0;
590}
591
592/**
593 *	pc87413_exit: module's "destructor"
594 *
595 *	Unload the watchdog. You cannot do this with any file handles open.
596 *	If your watchdog is set to continue ticking on close and you unload
597 *	it, well it keeps ticking. We won't get the interrupt but the board
598 *	will not touch PC memory so all is fine. You just have to load a new
599 *	module in 60 seconds or reboot.
600 */
601
602static void __exit pc87413_exit(void)
603{
604	/* Stop the timer before we leave */
605	if (!nowayout)
606	{
607		pc87413_disable();
608		printk(KERN_INFO MODNAME "Watchdog disabled.\n");
609	}
610
611	misc_deregister(&pc87413_miscdev);
612	unregister_reboot_notifier(&pc87413_notifier);
613	/* release_region(io,2); */
614
615	printk(MODNAME " watchdog component driver removed.\n");
616}
617
618module_init(pc87413_init);
619module_exit(pc87413_exit);
620
621MODULE_AUTHOR("Sven Anders <anders@anduras.de>, Marcus Junker <junker@anduras.de>,");
622MODULE_DESCRIPTION("PC87413 WDT driver");
623MODULE_LICENSE("GPL");
624
625MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
626
627module_param(io, int, 0);
628MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ").");
629
630module_param(timeout, int, 0);
631MODULE_PARM_DESC(timeout, "Watchdog timeout in minutes (default=" __MODULE_STRING(timeout) ").");
632
633module_param(nowayout, int, 0);
634MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
635