1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *	sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
4  *			integrated watchdog.
5  *
6  *	(c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
7  *
8  *	Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
9  *	provide warranty for any of this software. This material is
10  *	provided "AS-IS" and at no charge.
11  */
12 
13 /*
14  *	Includes, defines, variables, module parameters, ...
15  */
16 
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 
19 /* Includes */
20 #include <linux/module.h>		/* For module specific items */
21 #include <linux/moduleparam.h>		/* For new moduleparam's */
22 #include <linux/types.h>		/* For standard types (like size_t) */
23 #include <linux/errno.h>		/* For the -ENODEV/... values */
24 #include <linux/kernel.h>		/* For printk/... */
25 #include <linux/miscdevice.h>		/* For struct miscdevice */
26 #include <linux/watchdog.h>		/* For the watchdog specific items */
27 #include <linux/init.h>			/* For __init/__exit/... */
28 #include <linux/fs.h>			/* For file operations */
29 #include <linux/platform_device.h>	/* For platform_driver framework */
30 #include <linux/ioport.h>		/* For io-port access */
31 #include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
32 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
33 #include <linux/io.h>			/* For inb/outb/... */
34 
35 /* Module and version information */
36 #define DRV_NAME	"sch311x_wdt"
37 
38 /* Runtime registers */
39 #define GP60			0x47
40 #define WDT_TIME_OUT		0x65
41 #define WDT_VAL			0x66
42 #define WDT_CFG			0x67
43 #define WDT_CTRL		0x68
44 
45 /* internal variables */
46 static unsigned long sch311x_wdt_is_open;
47 static char sch311x_wdt_expect_close;
48 static struct platform_device *sch311x_wdt_pdev;
49 
50 static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };
51 
52 static struct {	/* The devices private data */
53 	/* the Runtime Register base address */
54 	unsigned short runtime_reg;
55 	/* The card's boot status */
56 	int boot_status;
57 	/* the lock for io operations */
58 	spinlock_t io_lock;
59 } sch311x_wdt_data;
60 
61 /* Module load parameters */
62 static unsigned short force_id;
63 module_param(force_id, ushort, 0);
64 MODULE_PARM_DESC(force_id, "Override the detected device ID");
65 
66 #define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */
67 static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
68 module_param(timeout, int, 0);
69 MODULE_PARM_DESC(timeout,
70 	"Watchdog timeout in seconds. 1<= timeout <=15300, default="
71 		__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
72 
73 static bool nowayout = WATCHDOG_NOWAYOUT;
74 module_param(nowayout, bool, 0);
75 MODULE_PARM_DESC(nowayout,
76 	"Watchdog cannot be stopped once started (default="
77 		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
78 
79 /*
80  *	Super-IO functions
81  */
82 
83 static inline void sch311x_sio_enter(int sio_config_port)
84 {
85 	outb(0x55, sio_config_port);
86 }
87 
88 static inline void sch311x_sio_exit(int sio_config_port)
89 {
90 	outb(0xaa, sio_config_port);
91 }
92 
93 static inline int sch311x_sio_inb(int sio_config_port, int reg)
94 {
95 	outb(reg, sio_config_port);
96 	return inb(sio_config_port + 1);
97 }
98 
99 static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
100 {
101 	outb(reg, sio_config_port);
102 	outb(val, sio_config_port + 1);
103 }
104 
105 /*
106  *	Watchdog Operations
107  */
108 
109 static void sch311x_wdt_set_timeout(int t)
110 {
111 	unsigned char timeout_unit = 0x80;
112 
113 	/* When new timeout is bigger then 255 seconds, we will use minutes */
114 	if (t > 255) {
115 		timeout_unit = 0;
116 		t /= 60;
117 	}
118 
119 	/* -- Watchdog Timeout --
120 	 * Bit 0-6 (Reserved)
121 	 * Bit 7   WDT Time-out Value Units Select
122 	 *         (0 = Minutes, 1 = Seconds)
123 	 */
124 	outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);
125 
126 	/* -- Watchdog Timer Time-out Value --
127 	 * Bit 0-7 Binary coded units (0=Disabled, 1..255)
128 	 */
129 	outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
130 }
131 
132 static void sch311x_wdt_start(void)
133 {
134 	unsigned char t;
135 
136 	spin_lock(&sch311x_wdt_data.io_lock);
137 
138 	/* set watchdog's timeout */
139 	sch311x_wdt_set_timeout(timeout);
140 	/* enable the watchdog */
141 	/* -- General Purpose I/O Bit 6.0 --
142 	 * Bit 0,   In/Out: 0 = Output, 1 = Input
143 	 * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
144 	 * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
145 	 *                           10 = Either Edge Triggered Intr.4
146 	 * Bit 4-6  (Reserved)
147 	 * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
148 	 */
149 	t = inb(sch311x_wdt_data.runtime_reg + GP60);
150 	outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);
151 
152 	spin_unlock(&sch311x_wdt_data.io_lock);
153 
154 }
155 
156 static void sch311x_wdt_stop(void)
157 {
158 	unsigned char t;
159 
160 	spin_lock(&sch311x_wdt_data.io_lock);
161 
162 	/* stop the watchdog */
163 	t = inb(sch311x_wdt_data.runtime_reg + GP60);
164 	outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
165 	/* disable timeout by setting it to 0 */
166 	sch311x_wdt_set_timeout(0);
167 
168 	spin_unlock(&sch311x_wdt_data.io_lock);
169 }
170 
171 static void sch311x_wdt_keepalive(void)
172 {
173 	spin_lock(&sch311x_wdt_data.io_lock);
174 	sch311x_wdt_set_timeout(timeout);
175 	spin_unlock(&sch311x_wdt_data.io_lock);
176 }
177 
178 static int sch311x_wdt_set_heartbeat(int t)
179 {
180 	if (t < 1 || t > (255*60))
181 		return -EINVAL;
182 
183 	/* When new timeout is bigger then 255 seconds,
184 	 * we will round up to minutes (with a max of 255) */
185 	if (t > 255)
186 		t = (((t - 1) / 60) + 1) * 60;
187 
188 	timeout = t;
189 	return 0;
190 }
191 
192 static void sch311x_wdt_get_status(int *status)
193 {
194 	unsigned char new_status;
195 
196 	*status = 0;
197 
198 	spin_lock(&sch311x_wdt_data.io_lock);
199 
200 	/* -- Watchdog timer control --
201 	 * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occurred
202 	 * Bit 1   Reserved
203 	 * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
204 	 * Bit 3   P20 Force Timeout enabled:
205 	 *          0 = P20 activity does not generate the WD timeout event
206 	 *          1 = P20 Allows rising edge of P20, from the keyboard
207 	 *              controller, to force the WD timeout event.
208 	 * Bit 4-7 Reserved
209 	 */
210 	new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
211 	if (new_status & 0x01)
212 		*status |= WDIOF_CARDRESET;
213 
214 	spin_unlock(&sch311x_wdt_data.io_lock);
215 }
216 
217 /*
218  *	/dev/watchdog handling
219  */
220 
221 static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
222 						size_t count, loff_t *ppos)
223 {
224 	if (count) {
225 		if (!nowayout) {
226 			size_t i;
227 
228 			sch311x_wdt_expect_close = 0;
229 
230 			for (i = 0; i != count; i++) {
231 				char c;
232 				if (get_user(c, buf + i))
233 					return -EFAULT;
234 				if (c == 'V')
235 					sch311x_wdt_expect_close = 42;
236 			}
237 		}
238 		sch311x_wdt_keepalive();
239 	}
240 	return count;
241 }
242 
243 static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
244 							unsigned long arg)
245 {
246 	int status;
247 	int new_timeout;
248 	void __user *argp = (void __user *)arg;
249 	int __user *p = argp;
250 	static const struct watchdog_info ident = {
251 		.options		= WDIOF_KEEPALIVEPING |
252 					  WDIOF_SETTIMEOUT |
253 					  WDIOF_MAGICCLOSE,
254 		.firmware_version	= 1,
255 		.identity		= DRV_NAME,
256 	};
257 
258 	switch (cmd) {
259 	case WDIOC_GETSUPPORT:
260 		if (copy_to_user(argp, &ident, sizeof(ident)))
261 			return -EFAULT;
262 		break;
263 
264 	case WDIOC_GETSTATUS:
265 	{
266 		sch311x_wdt_get_status(&status);
267 		return put_user(status, p);
268 	}
269 	case WDIOC_GETBOOTSTATUS:
270 		return put_user(sch311x_wdt_data.boot_status, p);
271 
272 	case WDIOC_SETOPTIONS:
273 	{
274 		int options, retval = -EINVAL;
275 
276 		if (get_user(options, p))
277 			return -EFAULT;
278 		if (options & WDIOS_DISABLECARD) {
279 			sch311x_wdt_stop();
280 			retval = 0;
281 		}
282 		if (options & WDIOS_ENABLECARD) {
283 			sch311x_wdt_start();
284 			retval = 0;
285 		}
286 		return retval;
287 	}
288 	case WDIOC_KEEPALIVE:
289 		sch311x_wdt_keepalive();
290 		break;
291 
292 	case WDIOC_SETTIMEOUT:
293 		if (get_user(new_timeout, p))
294 			return -EFAULT;
295 		if (sch311x_wdt_set_heartbeat(new_timeout))
296 			return -EINVAL;
297 		sch311x_wdt_keepalive();
298 		fallthrough;
299 	case WDIOC_GETTIMEOUT:
300 		return put_user(timeout, p);
301 	default:
302 		return -ENOTTY;
303 	}
304 	return 0;
305 }
306 
307 static int sch311x_wdt_open(struct inode *inode, struct file *file)
308 {
309 	if (test_and_set_bit(0, &sch311x_wdt_is_open))
310 		return -EBUSY;
311 	/*
312 	 *	Activate
313 	 */
314 	sch311x_wdt_start();
315 	return stream_open(inode, file);
316 }
317 
318 static int sch311x_wdt_close(struct inode *inode, struct file *file)
319 {
320 	if (sch311x_wdt_expect_close == 42) {
321 		sch311x_wdt_stop();
322 	} else {
323 		pr_crit("Unexpected close, not stopping watchdog!\n");
324 		sch311x_wdt_keepalive();
325 	}
326 	clear_bit(0, &sch311x_wdt_is_open);
327 	sch311x_wdt_expect_close = 0;
328 	return 0;
329 }
330 
331 /*
332  *	Kernel Interfaces
333  */
334 
335 static const struct file_operations sch311x_wdt_fops = {
336 	.owner		= THIS_MODULE,
337 	.llseek		= no_llseek,
338 	.write		= sch311x_wdt_write,
339 	.unlocked_ioctl	= sch311x_wdt_ioctl,
340 	.compat_ioctl	= compat_ptr_ioctl,
341 	.open		= sch311x_wdt_open,
342 	.release	= sch311x_wdt_close,
343 };
344 
345 static struct miscdevice sch311x_wdt_miscdev = {
346 	.minor	= WATCHDOG_MINOR,
347 	.name	= "watchdog",
348 	.fops	= &sch311x_wdt_fops,
349 };
350 
351 /*
352  *	Init & exit routines
353  */
354 
355 static int sch311x_wdt_probe(struct platform_device *pdev)
356 {
357 	struct device *dev = &pdev->dev;
358 	int err;
359 
360 	spin_lock_init(&sch311x_wdt_data.io_lock);
361 
362 	if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
363 		dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
364 			sch311x_wdt_data.runtime_reg + GP60,
365 			sch311x_wdt_data.runtime_reg + GP60);
366 		err = -EBUSY;
367 		goto exit;
368 	}
369 
370 	if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
371 								DRV_NAME)) {
372 		dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
373 			sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
374 			sch311x_wdt_data.runtime_reg + WDT_CTRL);
375 		err = -EBUSY;
376 		goto exit_release_region;
377 	}
378 
379 	/* Make sure that the watchdog is not running */
380 	sch311x_wdt_stop();
381 
382 	/* Disable keyboard and mouse interaction and interrupt */
383 	/* -- Watchdog timer configuration --
384 	 * Bit 0   Reserved
385 	 * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
386 	 * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
387 	 * Bit 3   Reserved
388 	 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
389 	 *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
390 	 */
391 	outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);
392 
393 	/* Check that the heartbeat value is within it's range ;
394 	 * if not reset to the default */
395 	if (sch311x_wdt_set_heartbeat(timeout)) {
396 		sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
397 		dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
398 			timeout);
399 	}
400 
401 	/* Get status at boot */
402 	sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);
403 
404 	sch311x_wdt_miscdev.parent = dev;
405 
406 	err = misc_register(&sch311x_wdt_miscdev);
407 	if (err != 0) {
408 		dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
409 							WATCHDOG_MINOR, err);
410 		goto exit_release_region2;
411 	}
412 
413 	dev_info(dev,
414 		"SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
415 		timeout, nowayout);
416 
417 	return 0;
418 
419 exit_release_region2:
420 	release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
421 exit_release_region:
422 	release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
423 	sch311x_wdt_data.runtime_reg = 0;
424 exit:
425 	return err;
426 }
427 
428 static void sch311x_wdt_remove(struct platform_device *pdev)
429 {
430 	/* Stop the timer before we leave */
431 	if (!nowayout)
432 		sch311x_wdt_stop();
433 
434 	/* Deregister */
435 	misc_deregister(&sch311x_wdt_miscdev);
436 	release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
437 	release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
438 	sch311x_wdt_data.runtime_reg = 0;
439 }
440 
441 static void sch311x_wdt_shutdown(struct platform_device *dev)
442 {
443 	/* Turn the WDT off if we have a soft shutdown */
444 	sch311x_wdt_stop();
445 }
446 
447 static struct platform_driver sch311x_wdt_driver = {
448 	.probe		= sch311x_wdt_probe,
449 	.remove_new	= sch311x_wdt_remove,
450 	.shutdown	= sch311x_wdt_shutdown,
451 	.driver		= {
452 		.name = DRV_NAME,
453 	},
454 };
455 
456 static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
457 {
458 	int err = 0, reg;
459 	unsigned short base_addr;
460 	unsigned char dev_id;
461 
462 	sch311x_sio_enter(sio_config_port);
463 
464 	/* Check device ID. We currently know about:
465 	 * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
466 	reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
467 	if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
468 		err = -ENODEV;
469 		goto exit;
470 	}
471 	dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
472 
473 	/* Select logical device A (runtime registers) */
474 	sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
475 
476 	/* Check if Logical Device Register is currently active */
477 	if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
478 		pr_info("Seems that LDN 0x0a is not active...\n");
479 
480 	/* Get the base address of the runtime registers */
481 	base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
482 			   sch311x_sio_inb(sio_config_port, 0x61);
483 	if (!base_addr) {
484 		pr_err("Base address not set\n");
485 		err = -ENODEV;
486 		goto exit;
487 	}
488 	*addr = base_addr;
489 
490 	pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
491 
492 exit:
493 	sch311x_sio_exit(sio_config_port);
494 	return err;
495 }
496 
497 static int __init sch311x_wdt_init(void)
498 {
499 	int err, i, found = 0;
500 	unsigned short addr = 0;
501 
502 	for (i = 0; !found && sch311x_ioports[i]; i++)
503 		if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
504 			found++;
505 
506 	if (!found)
507 		return -ENODEV;
508 
509 	sch311x_wdt_data.runtime_reg = addr;
510 
511 	err = platform_driver_register(&sch311x_wdt_driver);
512 	if (err)
513 		return err;
514 
515 	sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
516 								NULL, 0);
517 
518 	if (IS_ERR(sch311x_wdt_pdev)) {
519 		err = PTR_ERR(sch311x_wdt_pdev);
520 		goto unreg_platform_driver;
521 	}
522 
523 	return 0;
524 
525 unreg_platform_driver:
526 	platform_driver_unregister(&sch311x_wdt_driver);
527 	return err;
528 }
529 
530 static void __exit sch311x_wdt_exit(void)
531 {
532 	platform_device_unregister(sch311x_wdt_pdev);
533 	platform_driver_unregister(&sch311x_wdt_driver);
534 }
535 
536 module_init(sch311x_wdt_init);
537 module_exit(sch311x_wdt_exit);
538 
539 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
540 MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
541 MODULE_LICENSE("GPL");
542