xref: /linux/drivers/watchdog/sc1200wdt.c (revision 95298d63c67673c654c08952672d016212b26054) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
4  *	(c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
5  *			All Rights Reserved.
6  *	Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
7  *
8  *	The author(s) of this software shall not be held liable for damages
9  *	of any nature resulting due to the use of this software. This
10  *	software is provided AS-IS with no warranties.
11  *
12  *	Changelog:
13  *	20020220 Zwane Mwaikambo	Code based on datasheet, no hardware.
14  *	20020221 Zwane Mwaikambo	Cleanups as suggested by Jeff Garzik
15  *					and Alan Cox.
16  *	20020222 Zwane Mwaikambo	Added probing.
17  *	20020225 Zwane Mwaikambo	Added ISAPNP support.
18  *	20020412 Rob Radez		Broke out start/stop functions
19  *		 <rob@osinvestor.com>	Return proper status instead of
20  *					temperature warning
21  *					Add WDIOC_GETBOOTSTATUS and
22  *					WDIOC_SETOPTIONS ioctls
23  *					Fix CONFIG_WATCHDOG_NOWAYOUT
24  *	20020530 Joel Becker		Add Matt Domsch's nowayout module
25  *					option
26  *	20030116 Adam Belay		Updated to the latest pnp code
27  */
28 
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30 
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/miscdevice.h>
34 #include <linux/watchdog.h>
35 #include <linux/ioport.h>
36 #include <linux/spinlock.h>
37 #include <linux/notifier.h>
38 #include <linux/reboot.h>
39 #include <linux/init.h>
40 #include <linux/pnp.h>
41 #include <linux/fs.h>
42 #include <linux/semaphore.h>
43 #include <linux/io.h>
44 #include <linux/uaccess.h>
45 
46 #define SC1200_MODULE_VER	"build 20020303"
47 #define SC1200_MODULE_NAME	"sc1200wdt"
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 
70 static int timeout = 1;
71 static int io = -1;
72 static int io_len = 2;		/* for non plug and play */
73 static unsigned long open_flag;
74 static char expect_close;
75 static DEFINE_SPINLOCK(sc1200wdt_lock);	/* io port access serialisation */
76 
77 #if defined CONFIG_PNP
78 static int isapnp = 1;
79 static struct pnp_dev *wdt_dev;
80 
81 module_param(isapnp, int, 0);
82 MODULE_PARM_DESC(isapnp,
83 	"When set to 0 driver ISA PnP support will be disabled");
84 #endif
85 
86 module_param_hw(io, int, ioport, 0);
87 MODULE_PARM_DESC(io, "io port");
88 module_param(timeout, int, 0);
89 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
90 
91 static bool nowayout = WATCHDOG_NOWAYOUT;
92 module_param(nowayout, bool, 0);
93 MODULE_PARM_DESC(nowayout,
94 	"Watchdog cannot be stopped once started (default="
95 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
96 
97 
98 
99 /* Read from Data Register */
100 static inline void __sc1200wdt_read_data(unsigned char index,
101 						unsigned char *data)
102 {
103 	outb_p(index, PMIR);
104 	*data = inb(PMDR);
105 }
106 
107 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
108 {
109 	spin_lock(&sc1200wdt_lock);
110 	__sc1200wdt_read_data(index, data);
111 	spin_unlock(&sc1200wdt_lock);
112 }
113 
114 /* Write to Data Register */
115 static inline void __sc1200wdt_write_data(unsigned char index,
116 						unsigned char data)
117 {
118 	outb_p(index, PMIR);
119 	outb(data, PMDR);
120 }
121 
122 static inline void sc1200wdt_write_data(unsigned char index,
123 						unsigned char data)
124 {
125 	spin_lock(&sc1200wdt_lock);
126 	__sc1200wdt_write_data(index, data);
127 	spin_unlock(&sc1200wdt_lock);
128 }
129 
130 
131 static void sc1200wdt_start(void)
132 {
133 	unsigned char reg;
134 	spin_lock(&sc1200wdt_lock);
135 
136 	__sc1200wdt_read_data(WDCF, &reg);
137 	/* assert WDO when any of the following interrupts are triggered too */
138 	reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
139 	__sc1200wdt_write_data(WDCF, reg);
140 	/* set the timeout and get the ball rolling */
141 	__sc1200wdt_write_data(WDTO, timeout);
142 
143 	spin_unlock(&sc1200wdt_lock);
144 }
145 
146 static void sc1200wdt_stop(void)
147 {
148 	sc1200wdt_write_data(WDTO, 0);
149 }
150 
151 /* This returns the status of the WDO signal, inactive high. */
152 static inline int sc1200wdt_status(void)
153 {
154 	unsigned char ret;
155 
156 	sc1200wdt_read_data(WDST, &ret);
157 	/* If the bit is inactive, the watchdog is enabled, so return
158 	 * KEEPALIVEPING which is a bit of a kludge because there's nothing
159 	 * else for enabled/disabled status
160 	 */
161 	return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
162 }
163 
164 static int sc1200wdt_open(struct inode *inode, struct file *file)
165 {
166 	/* allow one at a time */
167 	if (test_and_set_bit(0, &open_flag))
168 		return -EBUSY;
169 
170 	if (timeout > MAX_TIMEOUT)
171 		timeout = MAX_TIMEOUT;
172 
173 	sc1200wdt_start();
174 	pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
175 
176 	return stream_open(inode, file);
177 }
178 
179 
180 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
181 						unsigned long arg)
182 {
183 	int new_timeout;
184 	void __user *argp = (void __user *)arg;
185 	int __user *p = argp;
186 	static const struct watchdog_info ident = {
187 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
188 							WDIOF_MAGICCLOSE,
189 		.firmware_version = 0,
190 		.identity = "PC87307/PC97307",
191 	};
192 
193 	switch (cmd) {
194 	case WDIOC_GETSUPPORT:
195 		if (copy_to_user(argp, &ident, sizeof(ident)))
196 			return -EFAULT;
197 		return 0;
198 
199 	case WDIOC_GETSTATUS:
200 		return put_user(sc1200wdt_status(), p);
201 
202 	case WDIOC_GETBOOTSTATUS:
203 		return put_user(0, p);
204 
205 	case WDIOC_SETOPTIONS:
206 	{
207 		int options, retval = -EINVAL;
208 
209 		if (get_user(options, p))
210 			return -EFAULT;
211 
212 		if (options & WDIOS_DISABLECARD) {
213 			sc1200wdt_stop();
214 			retval = 0;
215 		}
216 
217 		if (options & WDIOS_ENABLECARD) {
218 			sc1200wdt_start();
219 			retval = 0;
220 		}
221 
222 		return retval;
223 	}
224 	case WDIOC_KEEPALIVE:
225 		sc1200wdt_write_data(WDTO, timeout);
226 		return 0;
227 
228 	case WDIOC_SETTIMEOUT:
229 		if (get_user(new_timeout, p))
230 			return -EFAULT;
231 		/* the API states this is given in secs */
232 		new_timeout /= 60;
233 		if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
234 			return -EINVAL;
235 		timeout = new_timeout;
236 		sc1200wdt_write_data(WDTO, timeout);
237 		/* fall through - and return the new timeout */
238 
239 	case WDIOC_GETTIMEOUT:
240 		return put_user(timeout * 60, p);
241 
242 	default:
243 		return -ENOTTY;
244 	}
245 }
246 
247 
248 static int sc1200wdt_release(struct inode *inode, struct file *file)
249 {
250 	if (expect_close == 42) {
251 		sc1200wdt_stop();
252 		pr_info("Watchdog disabled\n");
253 	} else {
254 		sc1200wdt_write_data(WDTO, timeout);
255 		pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
256 	}
257 	clear_bit(0, &open_flag);
258 	expect_close = 0;
259 
260 	return 0;
261 }
262 
263 
264 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
265 						size_t len, loff_t *ppos)
266 {
267 	if (len) {
268 		if (!nowayout) {
269 			size_t i;
270 
271 			expect_close = 0;
272 
273 			for (i = 0; i != len; i++) {
274 				char c;
275 
276 				if (get_user(c, data + i))
277 					return -EFAULT;
278 				if (c == 'V')
279 					expect_close = 42;
280 			}
281 		}
282 
283 		sc1200wdt_write_data(WDTO, timeout);
284 		return len;
285 	}
286 
287 	return 0;
288 }
289 
290 
291 static int sc1200wdt_notify_sys(struct notifier_block *this,
292 					unsigned long code, void *unused)
293 {
294 	if (code == SYS_DOWN || code == SYS_HALT)
295 		sc1200wdt_stop();
296 
297 	return NOTIFY_DONE;
298 }
299 
300 
301 static struct notifier_block sc1200wdt_notifier = {
302 	.notifier_call =	sc1200wdt_notify_sys,
303 };
304 
305 static const struct file_operations sc1200wdt_fops = {
306 	.owner		= THIS_MODULE,
307 	.llseek		= no_llseek,
308 	.write		= sc1200wdt_write,
309 	.unlocked_ioctl = sc1200wdt_ioctl,
310 	.compat_ioctl	= compat_ptr_ioctl,
311 	.open		= sc1200wdt_open,
312 	.release	= sc1200wdt_release,
313 };
314 
315 static struct miscdevice sc1200wdt_miscdev = {
316 	.minor		= WATCHDOG_MINOR,
317 	.name		= "watchdog",
318 	.fops		= &sc1200wdt_fops,
319 };
320 
321 
322 static int __init sc1200wdt_probe(void)
323 {
324 	/* The probe works by reading the PMC3 register's default value of 0x0e
325 	 * there is one caveat, if the device disables the parallel port or any
326 	 * of the UARTs we won't be able to detect it.
327 	 * NB. This could be done with accuracy by reading the SID registers,
328 	 * but we don't have access to those io regions.
329 	 */
330 
331 	unsigned char reg;
332 
333 	sc1200wdt_read_data(PMC3, &reg);
334 	reg &= 0x0f;		/* we don't want the UART busy bits */
335 	return (reg == 0x0e) ? 0 : -ENODEV;
336 }
337 
338 
339 #if defined CONFIG_PNP
340 
341 static const struct pnp_device_id scl200wdt_pnp_devices[] = {
342 	/* National Semiconductor PC87307/PC97307 watchdog component */
343 	{.id = "NSC0800", .driver_data = 0},
344 	{.id = ""},
345 };
346 
347 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
348 					const struct pnp_device_id *dev_id)
349 {
350 	/* this driver only supports one card at a time */
351 	if (wdt_dev || !isapnp)
352 		return -EBUSY;
353 
354 	wdt_dev = dev;
355 	io = pnp_port_start(wdt_dev, 0);
356 	io_len = pnp_port_len(wdt_dev, 0);
357 
358 	if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
359 		pr_err("Unable to register IO port %#x\n", io);
360 		return -EBUSY;
361 	}
362 
363 	pr_info("PnP device found at io port %#x/%d\n", io, io_len);
364 	return 0;
365 }
366 
367 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
368 {
369 	if (wdt_dev) {
370 		release_region(io, io_len);
371 		wdt_dev = NULL;
372 	}
373 }
374 
375 static struct pnp_driver scl200wdt_pnp_driver = {
376 	.name		= "scl200wdt",
377 	.id_table	= scl200wdt_pnp_devices,
378 	.probe		= scl200wdt_pnp_probe,
379 	.remove		= scl200wdt_pnp_remove,
380 };
381 
382 #endif /* CONFIG_PNP */
383 
384 
385 static int __init sc1200wdt_init(void)
386 {
387 	int ret;
388 
389 	pr_info("%s\n", SC1200_MODULE_VER);
390 
391 #if defined CONFIG_PNP
392 	if (isapnp) {
393 		ret = pnp_register_driver(&scl200wdt_pnp_driver);
394 		if (ret)
395 			goto out_clean;
396 	}
397 #endif
398 
399 	if (io == -1) {
400 		pr_err("io parameter must be specified\n");
401 		ret = -EINVAL;
402 		goto out_pnp;
403 	}
404 
405 #if defined CONFIG_PNP
406 	/* now that the user has specified an IO port and we haven't detected
407 	 * any devices, disable pnp support */
408 	if (isapnp)
409 		pnp_unregister_driver(&scl200wdt_pnp_driver);
410 	isapnp = 0;
411 #endif
412 
413 	if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
414 		pr_err("Unable to register IO port %#x\n", io);
415 		ret = -EBUSY;
416 		goto out_pnp;
417 	}
418 
419 	ret = sc1200wdt_probe();
420 	if (ret)
421 		goto out_io;
422 
423 	ret = register_reboot_notifier(&sc1200wdt_notifier);
424 	if (ret) {
425 		pr_err("Unable to register reboot notifier err = %d\n", ret);
426 		goto out_io;
427 	}
428 
429 	ret = misc_register(&sc1200wdt_miscdev);
430 	if (ret) {
431 		pr_err("Unable to register miscdev on minor %d\n",
432 		       WATCHDOG_MINOR);
433 		goto out_rbt;
434 	}
435 
436 	/* ret = 0 */
437 
438 out_clean:
439 	return ret;
440 
441 out_rbt:
442 	unregister_reboot_notifier(&sc1200wdt_notifier);
443 
444 out_io:
445 	release_region(io, io_len);
446 
447 out_pnp:
448 #if defined CONFIG_PNP
449 	if (isapnp)
450 		pnp_unregister_driver(&scl200wdt_pnp_driver);
451 #endif
452 	goto out_clean;
453 }
454 
455 
456 static void __exit sc1200wdt_exit(void)
457 {
458 	misc_deregister(&sc1200wdt_miscdev);
459 	unregister_reboot_notifier(&sc1200wdt_notifier);
460 
461 #if defined CONFIG_PNP
462 	if (isapnp)
463 		pnp_unregister_driver(&scl200wdt_pnp_driver);
464 	else
465 #endif
466 	release_region(io, io_len);
467 }
468 
469 module_init(sc1200wdt_init);
470 module_exit(sc1200wdt_exit);
471 
472 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
473 MODULE_DESCRIPTION(
474 	"Driver for National Semiconductor PC87307/PC97307 watchdog component");
475 MODULE_LICENSE("GPL");
476