1 /*
2  *	sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
3  *			integrated watchdog.
4  *
5  *	(c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
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  *	Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
13  *	provide warranty for any of this software. This material is
14  *	provided "AS-IS" and at no charge.
15  */
16 
17 /*
18  *	Includes, defines, variables, module parameters, ...
19  */
20 
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 
23 /* Includes */
24 #include <linux/module.h>		/* For module specific items */
25 #include <linux/moduleparam.h>		/* For new moduleparam's */
26 #include <linux/types.h>		/* For standard types (like size_t) */
27 #include <linux/errno.h>		/* For the -ENODEV/... values */
28 #include <linux/kernel.h>		/* For printk/... */
29 #include <linux/miscdevice.h>		/* For struct miscdevice */
30 #include <linux/watchdog.h>		/* For the watchdog specific items */
31 #include <linux/init.h>			/* For __init/__exit/... */
32 #include <linux/fs.h>			/* For file operations */
33 #include <linux/platform_device.h>	/* For platform_driver framework */
34 #include <linux/ioport.h>		/* For io-port access */
35 #include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
36 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
37 #include <linux/io.h>			/* For inb/outb/... */
38 
39 /* Module and version information */
40 #define DRV_NAME	"sch311x_wdt"
41 
42 /* Runtime registers */
43 #define GP60			0x47
44 #define WDT_TIME_OUT		0x65
45 #define WDT_VAL			0x66
46 #define WDT_CFG			0x67
47 #define WDT_CTRL		0x68
48 
49 /* internal variables */
50 static unsigned long sch311x_wdt_is_open;
51 static char sch311x_wdt_expect_close;
52 static struct platform_device *sch311x_wdt_pdev;
53 
54 static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };
55 
56 static struct {	/* The devices private data */
57 	/* the Runtime Register base address */
58 	unsigned short runtime_reg;
59 	/* The card's boot status */
60 	int boot_status;
61 	/* the lock for io operations */
62 	spinlock_t io_lock;
63 } sch311x_wdt_data;
64 
65 /* Module load parameters */
66 static unsigned short force_id;
67 module_param(force_id, ushort, 0);
68 MODULE_PARM_DESC(force_id, "Override the detected device ID");
69 
70 #define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */
71 static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
72 module_param(timeout, int, 0);
73 MODULE_PARM_DESC(timeout,
74 	"Watchdog timeout in seconds. 1<= timeout <=15300, default="
75 		__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
76 
77 static bool nowayout = WATCHDOG_NOWAYOUT;
78 module_param(nowayout, bool, 0);
79 MODULE_PARM_DESC(nowayout,
80 	"Watchdog cannot be stopped once started (default="
81 		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
82 
83 /*
84  *	Super-IO functions
85  */
86 
87 static inline void sch311x_sio_enter(int sio_config_port)
88 {
89 	outb(0x55, sio_config_port);
90 }
91 
92 static inline void sch311x_sio_exit(int sio_config_port)
93 {
94 	outb(0xaa, sio_config_port);
95 }
96 
97 static inline int sch311x_sio_inb(int sio_config_port, int reg)
98 {
99 	outb(reg, sio_config_port);
100 	return inb(sio_config_port + 1);
101 }
102 
103 static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
104 {
105 	outb(reg, sio_config_port);
106 	outb(val, sio_config_port + 1);
107 }
108 
109 /*
110  *	Watchdog Operations
111  */
112 
113 static void sch311x_wdt_set_timeout(int t)
114 {
115 	unsigned char timeout_unit = 0x80;
116 
117 	/* When new timeout is bigger then 255 seconds, we will use minutes */
118 	if (t > 255) {
119 		timeout_unit = 0;
120 		t /= 60;
121 	}
122 
123 	/* -- Watchdog Timeout --
124 	 * Bit 0-6 (Reserved)
125 	 * Bit 7   WDT Time-out Value Units Select
126 	 *         (0 = Minutes, 1 = Seconds)
127 	 */
128 	outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);
129 
130 	/* -- Watchdog Timer Time-out Value --
131 	 * Bit 0-7 Binary coded units (0=Disabled, 1..255)
132 	 */
133 	outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
134 }
135 
136 static void sch311x_wdt_start(void)
137 {
138 	unsigned char t;
139 
140 	spin_lock(&sch311x_wdt_data.io_lock);
141 
142 	/* set watchdog's timeout */
143 	sch311x_wdt_set_timeout(timeout);
144 	/* enable the watchdog */
145 	/* -- General Purpose I/O Bit 6.0 --
146 	 * Bit 0,   In/Out: 0 = Output, 1 = Input
147 	 * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
148 	 * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
149 	 *                           10 = Either Edge Triggered Intr.4
150 	 * Bit 4-6  (Reserved)
151 	 * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
152 	 */
153 	t = inb(sch311x_wdt_data.runtime_reg + GP60);
154 	outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);
155 
156 	spin_unlock(&sch311x_wdt_data.io_lock);
157 
158 }
159 
160 static void sch311x_wdt_stop(void)
161 {
162 	unsigned char t;
163 
164 	spin_lock(&sch311x_wdt_data.io_lock);
165 
166 	/* stop the watchdog */
167 	t = inb(sch311x_wdt_data.runtime_reg + GP60);
168 	outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
169 	/* disable timeout by setting it to 0 */
170 	sch311x_wdt_set_timeout(0);
171 
172 	spin_unlock(&sch311x_wdt_data.io_lock);
173 }
174 
175 static void sch311x_wdt_keepalive(void)
176 {
177 	spin_lock(&sch311x_wdt_data.io_lock);
178 	sch311x_wdt_set_timeout(timeout);
179 	spin_unlock(&sch311x_wdt_data.io_lock);
180 }
181 
182 static int sch311x_wdt_set_heartbeat(int t)
183 {
184 	if (t < 1 || t > (255*60))
185 		return -EINVAL;
186 
187 	/* When new timeout is bigger then 255 seconds,
188 	 * we will round up to minutes (with a max of 255) */
189 	if (t > 255)
190 		t = (((t - 1) / 60) + 1) * 60;
191 
192 	timeout = t;
193 	return 0;
194 }
195 
196 static void sch311x_wdt_get_status(int *status)
197 {
198 	unsigned char new_status;
199 
200 	*status = 0;
201 
202 	spin_lock(&sch311x_wdt_data.io_lock);
203 
204 	/* -- Watchdog timer control --
205 	 * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occurred
206 	 * Bit 1   Reserved
207 	 * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
208 	 * Bit 3   P20 Force Timeout enabled:
209 	 *          0 = P20 activity does not generate the WD timeout event
210 	 *          1 = P20 Allows rising edge of P20, from the keyboard
211 	 *              controller, to force the WD timeout event.
212 	 * Bit 4-7 Reserved
213 	 */
214 	new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
215 	if (new_status & 0x01)
216 		*status |= WDIOF_CARDRESET;
217 
218 	spin_unlock(&sch311x_wdt_data.io_lock);
219 }
220 
221 /*
222  *	/dev/watchdog handling
223  */
224 
225 static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
226 						size_t count, loff_t *ppos)
227 {
228 	if (count) {
229 		if (!nowayout) {
230 			size_t i;
231 
232 			sch311x_wdt_expect_close = 0;
233 
234 			for (i = 0; i != count; i++) {
235 				char c;
236 				if (get_user(c, buf + i))
237 					return -EFAULT;
238 				if (c == 'V')
239 					sch311x_wdt_expect_close = 42;
240 			}
241 		}
242 		sch311x_wdt_keepalive();
243 	}
244 	return count;
245 }
246 
247 static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
248 							unsigned long arg)
249 {
250 	int status;
251 	int new_timeout;
252 	void __user *argp = (void __user *)arg;
253 	int __user *p = argp;
254 	static const struct watchdog_info ident = {
255 		.options		= WDIOF_KEEPALIVEPING |
256 					  WDIOF_SETTIMEOUT |
257 					  WDIOF_MAGICCLOSE,
258 		.firmware_version	= 1,
259 		.identity		= DRV_NAME,
260 	};
261 
262 	switch (cmd) {
263 	case WDIOC_GETSUPPORT:
264 		if (copy_to_user(argp, &ident, sizeof(ident)))
265 			return -EFAULT;
266 		break;
267 
268 	case WDIOC_GETSTATUS:
269 	{
270 		sch311x_wdt_get_status(&status);
271 		return put_user(status, p);
272 	}
273 	case WDIOC_GETBOOTSTATUS:
274 		return put_user(sch311x_wdt_data.boot_status, p);
275 
276 	case WDIOC_SETOPTIONS:
277 	{
278 		int options, retval = -EINVAL;
279 
280 		if (get_user(options, p))
281 			return -EFAULT;
282 		if (options & WDIOS_DISABLECARD) {
283 			sch311x_wdt_stop();
284 			retval = 0;
285 		}
286 		if (options & WDIOS_ENABLECARD) {
287 			sch311x_wdt_start();
288 			retval = 0;
289 		}
290 		return retval;
291 	}
292 	case WDIOC_KEEPALIVE:
293 		sch311x_wdt_keepalive();
294 		break;
295 
296 	case WDIOC_SETTIMEOUT:
297 		if (get_user(new_timeout, p))
298 			return -EFAULT;
299 		if (sch311x_wdt_set_heartbeat(new_timeout))
300 			return -EINVAL;
301 		sch311x_wdt_keepalive();
302 		/* Fall through */
303 	case WDIOC_GETTIMEOUT:
304 		return put_user(timeout, p);
305 	default:
306 		return -ENOTTY;
307 	}
308 	return 0;
309 }
310 
311 static int sch311x_wdt_open(struct inode *inode, struct file *file)
312 {
313 	if (test_and_set_bit(0, &sch311x_wdt_is_open))
314 		return -EBUSY;
315 	/*
316 	 *	Activate
317 	 */
318 	sch311x_wdt_start();
319 	return stream_open(inode, file);
320 }
321 
322 static int sch311x_wdt_close(struct inode *inode, struct file *file)
323 {
324 	if (sch311x_wdt_expect_close == 42) {
325 		sch311x_wdt_stop();
326 	} else {
327 		pr_crit("Unexpected close, not stopping watchdog!\n");
328 		sch311x_wdt_keepalive();
329 	}
330 	clear_bit(0, &sch311x_wdt_is_open);
331 	sch311x_wdt_expect_close = 0;
332 	return 0;
333 }
334 
335 /*
336  *	Kernel Interfaces
337  */
338 
339 static const struct file_operations sch311x_wdt_fops = {
340 	.owner		= THIS_MODULE,
341 	.llseek		= no_llseek,
342 	.write		= sch311x_wdt_write,
343 	.unlocked_ioctl	= sch311x_wdt_ioctl,
344 	.open		= sch311x_wdt_open,
345 	.release	= sch311x_wdt_close,
346 };
347 
348 static struct miscdevice sch311x_wdt_miscdev = {
349 	.minor	= WATCHDOG_MINOR,
350 	.name	= "watchdog",
351 	.fops	= &sch311x_wdt_fops,
352 };
353 
354 /*
355  *	Init & exit routines
356  */
357 
358 static int sch311x_wdt_probe(struct platform_device *pdev)
359 {
360 	struct device *dev = &pdev->dev;
361 	int err;
362 
363 	spin_lock_init(&sch311x_wdt_data.io_lock);
364 
365 	if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
366 		dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
367 			sch311x_wdt_data.runtime_reg + GP60,
368 			sch311x_wdt_data.runtime_reg + GP60);
369 		err = -EBUSY;
370 		goto exit;
371 	}
372 
373 	if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
374 								DRV_NAME)) {
375 		dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
376 			sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
377 			sch311x_wdt_data.runtime_reg + WDT_CTRL);
378 		err = -EBUSY;
379 		goto exit_release_region;
380 	}
381 
382 	/* Make sure that the watchdog is not running */
383 	sch311x_wdt_stop();
384 
385 	/* Disable keyboard and mouse interaction and interrupt */
386 	/* -- Watchdog timer configuration --
387 	 * Bit 0   Reserved
388 	 * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
389 	 * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
390 	 * Bit 3   Reserved
391 	 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
392 	 *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
393 	 */
394 	outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);
395 
396 	/* Check that the heartbeat value is within it's range ;
397 	 * if not reset to the default */
398 	if (sch311x_wdt_set_heartbeat(timeout)) {
399 		sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
400 		dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
401 			timeout);
402 	}
403 
404 	/* Get status at boot */
405 	sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);
406 
407 	sch311x_wdt_miscdev.parent = dev;
408 
409 	err = misc_register(&sch311x_wdt_miscdev);
410 	if (err != 0) {
411 		dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
412 							WATCHDOG_MINOR, err);
413 		goto exit_release_region2;
414 	}
415 
416 	dev_info(dev,
417 		"SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
418 		timeout, nowayout);
419 
420 	return 0;
421 
422 exit_release_region2:
423 	release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
424 exit_release_region:
425 	release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
426 	sch311x_wdt_data.runtime_reg = 0;
427 exit:
428 	return err;
429 }
430 
431 static int sch311x_wdt_remove(struct platform_device *pdev)
432 {
433 	/* Stop the timer before we leave */
434 	if (!nowayout)
435 		sch311x_wdt_stop();
436 
437 	/* Deregister */
438 	misc_deregister(&sch311x_wdt_miscdev);
439 	release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
440 	release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
441 	sch311x_wdt_data.runtime_reg = 0;
442 	return 0;
443 }
444 
445 static void sch311x_wdt_shutdown(struct platform_device *dev)
446 {
447 	/* Turn the WDT off if we have a soft shutdown */
448 	sch311x_wdt_stop();
449 }
450 
451 static struct platform_driver sch311x_wdt_driver = {
452 	.probe		= sch311x_wdt_probe,
453 	.remove		= sch311x_wdt_remove,
454 	.shutdown	= sch311x_wdt_shutdown,
455 	.driver		= {
456 		.name = DRV_NAME,
457 	},
458 };
459 
460 static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
461 {
462 	int err = 0, reg;
463 	unsigned short base_addr;
464 	unsigned char dev_id;
465 
466 	sch311x_sio_enter(sio_config_port);
467 
468 	/* Check device ID. We currently know about:
469 	 * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
470 	reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
471 	if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
472 		err = -ENODEV;
473 		goto exit;
474 	}
475 	dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
476 
477 	/* Select logical device A (runtime registers) */
478 	sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
479 
480 	/* Check if Logical Device Register is currently active */
481 	if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
482 		pr_info("Seems that LDN 0x0a is not active...\n");
483 
484 	/* Get the base address of the runtime registers */
485 	base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
486 			   sch311x_sio_inb(sio_config_port, 0x61);
487 	if (!base_addr) {
488 		pr_err("Base address not set\n");
489 		err = -ENODEV;
490 		goto exit;
491 	}
492 	*addr = base_addr;
493 
494 	pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
495 
496 exit:
497 	sch311x_sio_exit(sio_config_port);
498 	return err;
499 }
500 
501 static int __init sch311x_wdt_init(void)
502 {
503 	int err, i, found = 0;
504 	unsigned short addr = 0;
505 
506 	for (i = 0; !found && sch311x_ioports[i]; i++)
507 		if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
508 			found++;
509 
510 	if (!found)
511 		return -ENODEV;
512 
513 	sch311x_wdt_data.runtime_reg = addr;
514 
515 	err = platform_driver_register(&sch311x_wdt_driver);
516 	if (err)
517 		return err;
518 
519 	sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
520 								NULL, 0);
521 
522 	if (IS_ERR(sch311x_wdt_pdev)) {
523 		err = PTR_ERR(sch311x_wdt_pdev);
524 		goto unreg_platform_driver;
525 	}
526 
527 	return 0;
528 
529 unreg_platform_driver:
530 	platform_driver_unregister(&sch311x_wdt_driver);
531 	return err;
532 }
533 
534 static void __exit sch311x_wdt_exit(void)
535 {
536 	platform_device_unregister(sch311x_wdt_pdev);
537 	platform_driver_unregister(&sch311x_wdt_driver);
538 }
539 
540 module_init(sch311x_wdt_init);
541 module_exit(sch311x_wdt_exit);
542 
543 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
544 MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
545 MODULE_LICENSE("GPL");
546