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