sc1200wdt.c revision 103a1d5c57fac3623613b130b104f5b03367b31c 
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
19 *					and Alan Cox.
20 *	20020222 Zwane Mwaikambo	Added probing.
21 *	20020225 Zwane Mwaikambo	Added ISAPNP support.
22 *	20020412 Rob Radez		Broke out start/stop functions
23 *		 <rob@osinvestor.com>	Return proper status instead of
24 *					temperature warning
25 *					Add WDIOC_GETBOOTSTATUS and
26 *					WDIOC_SETOPTIONS ioctls
27 *					Fix CONFIG_WATCHDOG_NOWAYOUT
28 *	20020530 Joel Becker		Add Matt Domsch's nowayout module
29 *					option
30 *	20030116 Adam Belay		Updated to the latest pnp code
31 *
32 */
33
34#include <linux/module.h>
35#include <linux/moduleparam.h>
36#include <linux/miscdevice.h>
37#include <linux/watchdog.h>
38#include <linux/ioport.h>
39#include <linux/spinlock.h>
40#include <linux/notifier.h>
41#include <linux/reboot.h>
42#include <linux/init.h>
43#include <linux/pnp.h>
44#include <linux/fs.h>
45#include <linux/semaphore.h>
46#include <linux/io.h>
47#include <linux/uaccess.h>
48
49#define SC1200_MODULE_VER	"build 20020303"
50#define SC1200_MODULE_NAME	"sc1200wdt"
51#define PFX			SC1200_MODULE_NAME ": "
52
53#define	MAX_TIMEOUT	255	/* 255 minutes */
54#define PMIR		(io)	/* Power Management Index Register */
55#define PMDR		(io+1)	/* Power Management Data Register */
56
57/* Data Register indexes */
58#define FER1		0x00	/* Function enable register 1 */
59#define FER2		0x01	/* Function enable register 2 */
60#define PMC1		0x02	/* Power Management Ctrl 1 */
61#define PMC2		0x03	/* Power Management Ctrl 2 */
62#define PMC3		0x04	/* Power Management Ctrl 3 */
63#define WDTO		0x05	/* Watchdog timeout register */
64#define	WDCF		0x06	/* Watchdog config register */
65#define WDST		0x07	/* Watchdog status register */
66
67/* WDCF bitfields - which devices assert WDO */
68#define KBC_IRQ		0x01	/* Keyboard Controller */
69#define MSE_IRQ		0x02	/* Mouse */
70#define UART1_IRQ	0x03	/* Serial0 */
71#define UART2_IRQ	0x04	/* Serial1 */
72/* 5 -7 are reserved */
73
74static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER;
75static int timeout = 1;
76static int io = -1;
77static int io_len = 2;		/* for non plug and play */
78static unsigned long open_flag;
79static char expect_close;
80static DEFINE_SPINLOCK(sc1200wdt_lock);	/* io port access serialisation */
81
82#if defined CONFIG_PNP
83static int isapnp = 1;
84static struct pnp_dev *wdt_dev;
85
86module_param(isapnp, int, 0);
87MODULE_PARM_DESC(isapnp,
88	"When set to 0 driver ISA PnP support will be disabled");
89#endif
90
91module_param(io, int, 0);
92MODULE_PARM_DESC(io, "io port");
93module_param(timeout, int, 0);
94MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
95
96static int nowayout = WATCHDOG_NOWAYOUT;
97module_param(nowayout, int, 0);
98MODULE_PARM_DESC(nowayout,
99	"Watchdog cannot be stopped once started (default="
100				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
101
102
103
104/* Read from Data Register */
105static inline void __sc1200wdt_read_data(unsigned char index,
106						unsigned char *data)
107{
108	outb_p(index, PMIR);
109	*data = inb(PMDR);
110}
111
112static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
113{
114	spin_lock(&sc1200wdt_lock);
115	__sc1200wdt_read_data(index, data);
116	spin_unlock(&sc1200wdt_lock);
117}
118
119/* Write to Data Register */
120static inline void __sc1200wdt_write_data(unsigned char index,
121						unsigned char data)
122{
123	outb_p(index, PMIR);
124	outb(data, PMDR);
125}
126
127static inline void sc1200wdt_write_data(unsigned char index,
128						unsigned char data)
129{
130	spin_lock(&sc1200wdt_lock);
131	__sc1200wdt_write_data(index, data);
132	spin_unlock(&sc1200wdt_lock);
133}
134
135
136static void sc1200wdt_start(void)
137{
138	unsigned char reg;
139	spin_lock(&sc1200wdt_lock);
140
141	__sc1200wdt_read_data(WDCF, &reg);
142	/* assert WDO when any of the following interrupts are triggered too */
143	reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
144	__sc1200wdt_write_data(WDCF, reg);
145	/* set the timeout and get the ball rolling */
146	__sc1200wdt_write_data(WDTO, timeout);
147
148	spin_unlock(&sc1200wdt_lock);
149}
150
151static void sc1200wdt_stop(void)
152{
153	sc1200wdt_write_data(WDTO, 0);
154}
155
156/* This returns the status of the WDO signal, inactive high. */
157static inline int sc1200wdt_status(void)
158{
159	unsigned char ret;
160
161	sc1200wdt_read_data(WDST, &ret);
162	/* If the bit is inactive, the watchdog is enabled, so return
163	 * KEEPALIVEPING which is a bit of a kludge because there's nothing
164	 * else for enabled/disabled status
165	 */
166	return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
167}
168
169static int sc1200wdt_open(struct inode *inode, struct file *file)
170{
171	/* allow one at a time */
172	if (test_and_set_bit(0, &open_flag))
173		return -EBUSY;
174
175	if (timeout > MAX_TIMEOUT)
176		timeout = MAX_TIMEOUT;
177
178	sc1200wdt_start();
179	printk(KERN_INFO PFX "Watchdog enabled, timeout = %d min(s)", timeout);
180
181	return nonseekable_open(inode, file);
182}
183
184
185static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
186						unsigned long arg)
187{
188	int new_timeout;
189	void __user *argp = (void __user *)arg;
190	int __user *p = argp;
191	static const struct watchdog_info ident = {
192		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
193							WDIOF_MAGICCLOSE,
194		.firmware_version = 0,
195		.identity = "PC87307/PC97307",
196	};
197
198	switch (cmd) {
199
200	case WDIOC_GETSUPPORT:
201		if (copy_to_user(argp, &ident, sizeof ident))
202			return -EFAULT;
203		return 0;
204
205	case WDIOC_GETSTATUS:
206		return put_user(sc1200wdt_status(), p);
207
208	case WDIOC_GETBOOTSTATUS:
209		return put_user(0, p);
210
211	case WDIOC_KEEPALIVE:
212		sc1200wdt_write_data(WDTO, timeout);
213		return 0;
214
215	case WDIOC_SETTIMEOUT:
216		if (get_user(new_timeout, p))
217			return -EFAULT;
218		/* the API states this is given in secs */
219		new_timeout /= 60;
220		if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
221			return -EINVAL;
222		timeout = new_timeout;
223		sc1200wdt_write_data(WDTO, timeout);
224		/* fall through and return the new timeout */
225
226	case WDIOC_GETTIMEOUT:
227		return put_user(timeout * 60, p);
228
229	case WDIOC_SETOPTIONS:
230	{
231		int options, retval = -EINVAL;
232
233		if (get_user(options, p))
234			return -EFAULT;
235
236		if (options & WDIOS_DISABLECARD) {
237			sc1200wdt_stop();
238			retval = 0;
239		}
240
241		if (options & WDIOS_ENABLECARD) {
242			sc1200wdt_start();
243			retval = 0;
244		}
245
246		return retval;
247	}
248	default:
249		return -ENOTTY;
250	}
251}
252
253
254static int sc1200wdt_release(struct inode *inode, struct file *file)
255{
256	if (expect_close == 42) {
257		sc1200wdt_stop();
258		printk(KERN_INFO PFX "Watchdog disabled\n");
259	} else {
260		sc1200wdt_write_data(WDTO, timeout);
261		printk(KERN_CRIT PFX
262			"Unexpected close!, timeout = %d min(s)\n", timeout);
263	}
264	clear_bit(0, &open_flag);
265	expect_close = 0;
266
267	return 0;
268}
269
270
271static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
272						size_t len, loff_t *ppos)
273{
274	if (len) {
275		if (!nowayout) {
276			size_t i;
277
278			expect_close = 0;
279
280			for (i = 0; i != len; i++) {
281				char c;
282
283				if (get_user(c, data+i))
284					return -EFAULT;
285				if (c == 'V')
286					expect_close = 42;
287			}
288		}
289
290		sc1200wdt_write_data(WDTO, timeout);
291		return len;
292	}
293
294	return 0;
295}
296
297
298static int sc1200wdt_notify_sys(struct notifier_block *this,
299					unsigned long code, void *unused)
300{
301	if (code == SYS_DOWN || code == SYS_HALT)
302		sc1200wdt_stop();
303
304	return NOTIFY_DONE;
305}
306
307
308static struct notifier_block sc1200wdt_notifier = {
309	.notifier_call =	sc1200wdt_notify_sys,
310};
311
312static const struct file_operations sc1200wdt_fops = {
313	.owner		= THIS_MODULE,
314	.llseek		= no_llseek,
315	.write		= sc1200wdt_write,
316	.unlocked_ioctl = sc1200wdt_ioctl,
317	.open		= sc1200wdt_open,
318	.release	= sc1200wdt_release,
319};
320
321static struct miscdevice sc1200wdt_miscdev = {
322	.minor		= WATCHDOG_MINOR,
323	.name		= "watchdog",
324	.fops		= &sc1200wdt_fops,
325};
326
327
328static int __init sc1200wdt_probe(void)
329{
330	/* The probe works by reading the PMC3 register's default value of 0x0e
331	 * there is one caveat, if the device disables the parallel port or any
332	 * of the UARTs we won't be able to detect it.
333	 * NB. This could be done with accuracy by reading the SID registers,
334	 * but we don't have access to those io regions.
335	 */
336
337	unsigned char reg;
338
339	sc1200wdt_read_data(PMC3, &reg);
340	reg &= 0x0f;		/* we don't want the UART busy bits */
341	return (reg == 0x0e) ? 0 : -ENODEV;
342}
343
344
345#if defined CONFIG_PNP
346
347static struct pnp_device_id scl200wdt_pnp_devices[] = {
348	/* National Semiconductor PC87307/PC97307 watchdog component */
349	{.id = "NSC0800", .driver_data = 0},
350	{.id = ""},
351};
352
353static int scl200wdt_pnp_probe(struct pnp_dev *dev,
354					const struct pnp_device_id *dev_id)
355{
356	/* this driver only supports one card at a time */
357	if (wdt_dev || !isapnp)
358		return -EBUSY;
359
360	wdt_dev = dev;
361	io = pnp_port_start(wdt_dev, 0);
362	io_len = pnp_port_len(wdt_dev, 0);
363
364	if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
365		printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
366		return -EBUSY;
367	}
368
369	printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
370								io, io_len);
371	return 0;
372}
373
374static void scl200wdt_pnp_remove(struct pnp_dev *dev)
375{
376	if (wdt_dev) {
377		release_region(io, io_len);
378		wdt_dev = NULL;
379	}
380}
381
382static struct pnp_driver scl200wdt_pnp_driver = {
383	.name		= "scl200wdt",
384	.id_table	= scl200wdt_pnp_devices,
385	.probe		= scl200wdt_pnp_probe,
386	.remove		= scl200wdt_pnp_remove,
387};
388
389#endif /* CONFIG_PNP */
390
391
392static int __init sc1200wdt_init(void)
393{
394	int ret;
395
396	printk("%s\n", banner);
397
398#if defined CONFIG_PNP
399	if (isapnp) {
400		ret = pnp_register_driver(&scl200wdt_pnp_driver);
401		if (ret)
402			goto out_clean;
403	}
404#endif
405
406	if (io == -1) {
407		printk(KERN_ERR PFX "io parameter must be specified\n");
408		ret = -EINVAL;
409		goto out_pnp;
410	}
411
412#if defined CONFIG_PNP
413	/* now that the user has specified an IO port and we haven't detected
414	 * any devices, disable pnp support */
415	isapnp = 0;
416	pnp_unregister_driver(&scl200wdt_pnp_driver);
417#endif
418
419	if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
420		printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
421		ret = -EBUSY;
422		goto out_pnp;
423	}
424
425	ret = sc1200wdt_probe();
426	if (ret)
427		goto out_io;
428
429	ret = register_reboot_notifier(&sc1200wdt_notifier);
430	if (ret) {
431		printk(KERN_ERR PFX
432			"Unable to register reboot notifier err = %d\n", ret);
433		goto out_io;
434	}
435
436	ret = misc_register(&sc1200wdt_miscdev);
437	if (ret) {
438		printk(KERN_ERR PFX
439			"Unable to register miscdev on minor %d\n",
440							WATCHDOG_MINOR);
441		goto out_rbt;
442	}
443
444	/* ret = 0 */
445
446out_clean:
447	return ret;
448
449out_rbt:
450	unregister_reboot_notifier(&sc1200wdt_notifier);
451
452out_io:
453	release_region(io, io_len);
454
455out_pnp:
456#if defined CONFIG_PNP
457	if (isapnp)
458		pnp_unregister_driver(&scl200wdt_pnp_driver);
459#endif
460	goto out_clean;
461}
462
463
464static void __exit sc1200wdt_exit(void)
465{
466	misc_deregister(&sc1200wdt_miscdev);
467	unregister_reboot_notifier(&sc1200wdt_notifier);
468
469#if defined CONFIG_PNP
470	if (isapnp)
471		pnp_unregister_driver(&scl200wdt_pnp_driver);
472	else
473#endif
474	release_region(io, io_len);
475}
476
477module_init(sc1200wdt_init);
478module_exit(sc1200wdt_exit);
479
480MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
481MODULE_DESCRIPTION("Driver for National Semiconductor PC87307/PC97307 watchdog component");
482MODULE_LICENSE("GPL");
483MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
484