1/*
2 *	National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
3 *	(c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
4 *			All Rights Reserved.
5 *	Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
6 *
7 *	This program is free software; you can redistribute it and/or
8 *	modify it under the terms of the GNU General Public License
9 *	as published by the Free Software Foundation; either version
10 *	2 of the License, or (at your option) any later version.
11 *
12 *	The author(s) of this software shall not be held liable for damages
13 *	of any nature resulting due to the use of this software. This
14 *	software is provided AS-IS with no warranties.
15 *
16 *	Changelog:
17 *	20020220 Zwane Mwaikambo	Code based on datasheet, no hardware.
18 *	20020221 Zwane Mwaikambo	Cleanups as suggested by Jeff Garzik and Alan Cox.
19 *	20020222 Zwane Mwaikambo	Added probing.
20 *	20020225 Zwane Mwaikambo	Added ISAPNP support.
21 *	20020412 Rob Radez		Broke out start/stop functions
22 *		 <rob@osinvestor.com>	Return proper status instead of temperature warning
23 *					Add WDIOC_GETBOOTSTATUS and WDIOC_SETOPTIONS ioctls
24 *					Fix CONFIG_WATCHDOG_NOWAYOUT
25 *	20020530 Joel Becker		Add Matt Domsch's nowayout
26 *					module option
27 */
28
29#include <linux/config.h>
30#include <linux/module.h>
31#include <linux/kernel.h>
32#include <linux/miscdevice.h>
33#include <linux/watchdog.h>
34#include <linux/ioport.h>
35#include <linux/spinlock.h>
36#include <linux/ioport.h>
37#include <asm/semaphore.h>
38#include <asm/io.h>
39#include <asm/uaccess.h>
40#include <linux/notifier.h>
41#include <linux/reboot.h>
42#include <linux/init.h>
43#include <linux/isapnp.h>
44
45#define SC1200_MODULE_VER	"build 20020303"
46#define SC1200_MODULE_NAME	"sc1200wdt"
47#define PFX			SC1200_MODULE_NAME ": "
48
49#define	MAX_TIMEOUT	255	/* 255 minutes */
50#define PMIR		(io)	/* Power Management Index Register */
51#define PMDR		(io+1)	/* Power Management Data Register */
52
53/* Data Register indexes */
54#define FER1		0x00	/* Function enable register 1 */
55#define FER2		0x01	/* Function enable register 2 */
56#define PMC1		0x02	/* Power Management Ctrl 1 */
57#define PMC2		0x03	/* Power Management Ctrl 2 */
58#define PMC3		0x04	/* Power Management Ctrl 3 */
59#define WDTO		0x05	/* Watchdog timeout register */
60#define	WDCF		0x06	/* Watchdog config register */
61#define WDST		0x07	/* Watchdog status register */
62
63/* WDCF bitfields - which devices assert WDO */
64#define KBC_IRQ		0x01	/* Keyboard Controller */
65#define MSE_IRQ		0x02	/* Mouse */
66#define UART1_IRQ	0x03	/* Serial0 */
67#define UART2_IRQ	0x04	/* Serial1 */
68/* 5 -7 are reserved */
69
70static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER;
71static int timeout = 1;
72static int io = -1;
73static int io_len = 2;		/* for non plug and play */
74struct semaphore open_sem;
75static char expect_close;
76spinlock_t sc1200wdt_lock;	/* io port access serialisation */
77
78#if defined CONFIG_ISAPNP || defined CONFIG_ISAPNP_MODULE
79static int isapnp = 1;
80static struct pci_dev *wdt_dev;
81
82MODULE_PARM(isapnp, "i");
83MODULE_PARM_DESC(isapnp, "When set to 0 driver ISA PnP support will be disabled");
84#endif
85
86MODULE_PARM(io, "i");
87MODULE_PARM_DESC(io, "io port");
88MODULE_PARM(timeout, "i");
89MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
90
91#ifdef CONFIG_WATCHDOG_NOWAYOUT
92static int nowayout = 1;
93#else
94static int nowayout = 0;
95#endif
96
97MODULE_PARM(nowayout,"i");
98MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
99
100
101/* Read from Data Register */
102static inline void sc1200wdt_read_data(unsigned char index, unsigned char *data)
103{
104	spin_lock(&sc1200wdt_lock);
105	outb_p(index, PMIR);
106	*data = inb(PMDR);
107	spin_unlock(&sc1200wdt_lock);
108}
109
110
111/* Write to Data Register */
112static inline void sc1200wdt_write_data(unsigned char index, unsigned char data)
113{
114	spin_lock(&sc1200wdt_lock);
115	outb_p(index, PMIR);
116	outb(data, PMDR);
117	spin_unlock(&sc1200wdt_lock);
118}
119
120
121static void sc1200wdt_start(void)
122{
123	unsigned char reg;
124
125	sc1200wdt_read_data(WDCF, &reg);
126	/* assert WDO when any of the following interrupts are triggered too */
127	reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
128	sc1200wdt_write_data(WDCF, reg);
129	/* set the timeout and get the ball rolling */
130	sc1200wdt_write_data(WDTO, timeout);
131}
132
133
134static void sc1200wdt_stop(void)
135{
136	sc1200wdt_write_data(WDTO, 0);
137}
138
139
140/* This returns the status of the WDO signal, inactive high. */
141static inline int sc1200wdt_status(void)
142{
143	unsigned char ret;
144
145	sc1200wdt_read_data(WDST, &ret);
146	/* If the bit is inactive, the watchdog is enabled, so return
147	 * KEEPALIVEPING which is a bit of a kludge because there's nothing
148	 * else for enabled/disabled status
149	 */
150	return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;	/* bits 1 - 7 are undefined */
151}
152
153
154static int sc1200wdt_open(struct inode *inode, struct file *file)
155{
156	/* allow one at a time */
157	if (down_trylock(&open_sem))
158		return -EBUSY;
159
160	if (timeout > MAX_TIMEOUT)
161		timeout = MAX_TIMEOUT;
162
163	sc1200wdt_start();
164	printk(KERN_INFO PFX "Watchdog enabled, timeout = %d min(s)", timeout);
165
166	return 0;
167}
168
169
170static int sc1200wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
171{
172	int new_timeout;
173	static struct watchdog_info ident = {
174		options:		WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
175		firmware_version:	0,
176		identity:		"PC87307/PC97307"
177	};
178
179	switch (cmd) {
180		default:
181			return -ENOTTY;	/* Keep Pavel Machek amused ;) */
182
183		case WDIOC_GETSUPPORT:
184			if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof ident))
185				return -EFAULT;
186			return 0;
187
188		case WDIOC_GETSTATUS:
189			return put_user(sc1200wdt_status(), (int *)arg);
190
191		case WDIOC_GETBOOTSTATUS:
192			return put_user(0, (int *)arg);
193
194		case WDIOC_KEEPALIVE:
195			sc1200wdt_write_data(WDTO, timeout);
196			return 0;
197
198		case WDIOC_SETTIMEOUT:
199			if (get_user(new_timeout, (int *)arg))
200				return -EFAULT;
201
202			/* the API states this is given in secs */
203			new_timeout /= 60;
204			if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
205				return -EINVAL;
206
207			timeout = new_timeout;
208			sc1200wdt_write_data(WDTO, timeout);
209			/* fall through and return the new timeout */
210
211		case WDIOC_GETTIMEOUT:
212			return put_user(timeout * 60, (int *)arg);
213
214		case WDIOC_SETOPTIONS:
215		{
216			int options, retval = -EINVAL;
217
218			if (get_user(options, (int *)arg))
219				return -EFAULT;
220
221			if (options & WDIOS_DISABLECARD) {
222				sc1200wdt_stop();
223				retval = 0;
224			}
225
226			if (options & WDIOS_ENABLECARD) {
227				sc1200wdt_start();
228				retval = 0;
229			}
230
231			return retval;
232		}
233	}
234}
235
236
237static int sc1200wdt_release(struct inode *inode, struct file *file)
238{
239	if (expect_close == 42) {
240		sc1200wdt_stop();
241		printk(KERN_INFO PFX "Watchdog disabled\n");
242	} else {
243		sc1200wdt_write_data(WDTO, timeout);
244		printk(KERN_CRIT PFX "Unexpected close!, timeout = %d min(s)\n", timeout);
245	}
246	up(&open_sem);
247	expect_close = 0;
248
249	return 0;
250}
251
252
253static ssize_t sc1200wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
254{
255	if (ppos != &file->f_pos)
256		return -ESPIPE;
257
258	if (len) {
259		if (!nowayout) {
260			size_t i;
261
262			expect_close = 0;
263
264			for (i = 0; i != len; i++)
265			{
266				char c;
267				if(get_user(c, data+i))
268					return -EFAULT;
269				if (c == 'V')
270					expect_close = 42;
271			}
272		}
273		sc1200wdt_write_data(WDTO, timeout);
274		return len;
275	}
276
277	return 0;
278}
279
280
281static int sc1200wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
282{
283	if (code == SYS_DOWN || code == SYS_HALT)
284		sc1200wdt_stop();
285
286	return NOTIFY_DONE;
287}
288
289
290static struct notifier_block sc1200wdt_notifier =
291{
292	notifier_call:	sc1200wdt_notify_sys
293};
294
295static struct file_operations sc1200wdt_fops =
296{
297	owner:		THIS_MODULE,
298	write:		sc1200wdt_write,
299	ioctl:		sc1200wdt_ioctl,
300	open:		sc1200wdt_open,
301	release:	sc1200wdt_release
302};
303
304static struct miscdevice sc1200wdt_miscdev =
305{
306	minor:		WATCHDOG_MINOR,
307	name:		"watchdog",
308	fops:		&sc1200wdt_fops,
309};
310
311
312static int __init sc1200wdt_probe(void)
313{
314	/* The probe works by reading the PMC3 register's default value of 0x0e
315	 * there is one caveat, if the device disables the parallel port or any
316	 * of the UARTs we won't be able to detect it.
317	 * Nb. This could be done with accuracy by reading the SID registers, but
318	 * we don't have access to those io regions.
319	 */
320
321	unsigned char reg;
322
323	sc1200wdt_read_data(PMC3, &reg);
324	reg &= 0x0f;				/* we don't want the UART busy bits */
325	return (reg == 0x0e) ? 0 : -ENODEV;
326}
327
328
329#if defined CONFIG_ISAPNP || defined CONFIG_ISAPNP_MODULE
330
331static int __init sc1200wdt_isapnp_probe(void)
332{
333	int ret;
334
335	/* The WDT is logical device 8 on the main device */
336	wdt_dev = isapnp_find_dev(NULL, ISAPNP_VENDOR('N','S','C'), ISAPNP_FUNCTION(0x08), NULL);
337	if (!wdt_dev)
338		return -ENODEV;
339
340	if (wdt_dev->prepare(wdt_dev) < 0) {
341		printk(KERN_ERR PFX "ISA PnP found device that could not be autoconfigured\n");
342		return -EAGAIN;
343	}
344
345	if (!(pci_resource_flags(wdt_dev, 0) & IORESOURCE_IO)) {
346		printk(KERN_ERR PFX "ISA PnP could not find io ports\n");
347		return -ENODEV;
348	}
349
350	ret = wdt_dev->activate(wdt_dev);
351	if (ret && (ret != -EBUSY))
352		return -ENOMEM;
353
354	/* io port resource overriding support? */
355	io = pci_resource_start(wdt_dev, 0);
356	io_len = pci_resource_len(wdt_dev, 0);
357
358	printk(KERN_DEBUG PFX "ISA PnP found device at io port %#x/%d\n", io, io_len);
359	return 0;
360}
361
362#endif /* CONFIG_ISAPNP */
363
364
365static int __init sc1200wdt_init(void)
366{
367	int ret;
368
369	printk(banner);
370
371	spin_lock_init(&sc1200wdt_lock);
372	sema_init(&open_sem, 1);
373
374#if defined CONFIG_ISAPNP || defined CONFIG_ISAPNP_MODULE
375	if (isapnp) {
376		ret = sc1200wdt_isapnp_probe();
377		if (ret)
378			goto out_clean;
379	}
380#endif
381
382	if (io == -1) {
383		printk(KERN_ERR PFX "io parameter must be specified\n");
384		ret = -EINVAL;
385		goto out_clean;
386	}
387
388	if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
389		printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
390		ret = -EBUSY;
391		goto out_pnp;
392	}
393
394	ret = sc1200wdt_probe();
395	if (ret)
396		goto out_io;
397
398	ret = register_reboot_notifier(&sc1200wdt_notifier);
399	if (ret) {
400		printk(KERN_ERR PFX "Unable to register reboot notifier err = %d\n", ret);
401		goto out_io;
402	}
403
404	ret = misc_register(&sc1200wdt_miscdev);
405	if (ret) {
406		printk(KERN_ERR PFX "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR);
407		goto out_rbt;
408	}
409
410	/* ret = 0 */
411
412out_clean:
413	return ret;
414
415out_rbt:
416	unregister_reboot_notifier(&sc1200wdt_notifier);
417
418out_io:
419	release_region(io, io_len);
420
421out_pnp:
422#if defined CONFIG_ISAPNP || defined CONFIG_ISAPNP_MODULE
423	if (isapnp && wdt_dev)
424		wdt_dev->deactivate(wdt_dev);
425#endif
426	goto out_clean;
427}
428
429
430static void __exit sc1200wdt_exit(void)
431{
432	misc_deregister(&sc1200wdt_miscdev);
433	unregister_reboot_notifier(&sc1200wdt_notifier);
434
435#if defined CONFIG_ISAPNP || defined CONFIG_ISAPNP_MODULE
436	if(isapnp && wdt_dev)
437		wdt_dev->deactivate(wdt_dev);
438#endif
439
440	release_region(io, io_len);
441}
442
443
444#ifndef MODULE
445static int __init sc1200wdt_setup(char *str)
446{
447	int ints[4];
448
449	str = get_options (str, ARRAY_SIZE(ints), ints);
450
451	if (ints[0] > 0) {
452		io = ints[1];
453		if (ints[0] > 1)
454			timeout = ints[2];
455
456#if defined CONFIG_ISAPNP || defined CONFIG_ISAPNP_MODULE
457		if (ints[0] > 2)
458			isapnp = ints[3];
459#endif
460	}
461
462	return 1;
463}
464
465__setup("sc1200wdt=", sc1200wdt_setup);
466#endif /* MODULE */
467
468
469module_init(sc1200wdt_init);
470module_exit(sc1200wdt_exit);
471
472MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
473MODULE_DESCRIPTION("Driver for National Semiconductor PC87307/PC97307 watchdog component");
474MODULE_LICENSE("GPL");
475EXPORT_NO_SYMBOLS;
476
477