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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
4 *
5 * Based on acquirewdt.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
6 * and some other existing drivers
7 *
8 * The authors do NOT admit liability nor provide warranty for
9 * any of this software. This material is provided "AS-IS" in
10 * the hope that it may be useful for others.
11 *
12 * (C) Copyright 2003-2006 Sven Anders <anders@anduras.de>
13 *
14 * History:
15 * 2003 - Created version 1.0 for Linux 2.4.x.
16 * 2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE
17 * features. Released version 1.1
18 *
19 * Theory of operation:
20 *
21 * A Watchdog Timer (WDT) is a hardware circuit that can
22 * reset the computer system in case of a software fault.
23 * You probably knew that already.
24 *
25 * Usually a userspace daemon will notify the kernel WDT driver
26 * via the /dev/watchdog special device file that userspace is
27 * still alive, at regular intervals. When such a notification
28 * occurs, the driver will usually tell the hardware watchdog
29 * that everything is in order, and that the watchdog should wait
30 * for yet another little while to reset the system.
31 * If userspace fails (RAM error, kernel bug, whatever), the
32 * notifications cease to occur, and the hardware watchdog will
33 * reset the system (causing a reboot) after the timeout occurs.
34 *
35 * Create device with:
36 * mknod /dev/watchdog c 10 130
37 *
38 * For an example userspace keep-alive daemon, see:
39 * Documentation/watchdog/wdt.rst
40 */
41
42#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
43
44#include <linux/module.h>
45#include <linux/moduleparam.h>
46#include <linux/types.h>
47#include <linux/miscdevice.h>
48#include <linux/watchdog.h>
49#include <linux/delay.h>
50#include <linux/fs.h>
51#include <linux/ioport.h>
52#include <linux/notifier.h>
53#include <linux/reboot.h>
54#include <linux/init.h>
55#include <linux/spinlock.h>
56#include <linux/io.h>
57#include <linux/uaccess.h>
58
59
60/* enable support for minutes as units? */
61/* (does not always work correctly, so disabled by default!) */
62#define SMSC_SUPPORT_MINUTES
63#undef SMSC_SUPPORT_MINUTES
64
65#define MAX_TIMEOUT 255
66
67#define UNIT_SECOND 0
68#define UNIT_MINUTE 1
69
70#define VERSION "1.1"
71
72#define IOPORT 0x3F0
73#define IOPORT_SIZE 2
74#define IODEV_NO 8
75
76static int unit = UNIT_SECOND; /* timer's unit */
77static int timeout = 60; /* timeout value: default is 60 "units" */
78static unsigned long timer_enabled; /* is the timer enabled? */
79
80static char expect_close; /* is the close expected? */
81
82static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */
83
84static bool nowayout = WATCHDOG_NOWAYOUT;
85
86/* -- Low level function ----------------------------------------*/
87
88/* unlock the IO chip */
89
90static inline void open_io_config(void)
91{
92 outb(0x55, IOPORT);
93 mdelay(1);
94 outb(0x55, IOPORT);
95}
96
97/* lock the IO chip */
98static inline void close_io_config(void)
99{
100 outb(0xAA, IOPORT);
101}
102
103/* select the IO device */
104static inline void select_io_device(unsigned char devno)
105{
106 outb(0x07, IOPORT);
107 outb(devno, IOPORT+1);
108}
109
110/* write to the control register */
111static inline void write_io_cr(unsigned char reg, unsigned char data)
112{
113 outb(reg, IOPORT);
114 outb(data, IOPORT+1);
115}
116
117/* read from the control register */
118static inline char read_io_cr(unsigned char reg)
119{
120 outb(reg, IOPORT);
121 return inb(IOPORT+1);
122}
123
124/* -- Medium level functions ------------------------------------*/
125
126static inline void gpio_bit12(unsigned char reg)
127{
128 /* -- General Purpose I/O Bit 1.2 --
129 * Bit 0, In/Out: 0 = Output, 1 = Input
130 * Bit 1, Polarity: 0 = No Invert, 1 = Invert
131 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable
132 * Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17,
133 * 11 = Either Edge Triggered Intr. 2
134 * Bit 5/6 (Reserved)
135 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
136 */
137 write_io_cr(0xE2, reg);
138}
139
140static inline void gpio_bit13(unsigned char reg)
141{
142 /* -- General Purpose I/O Bit 1.3 --
143 * Bit 0, In/Out: 0 = Output, 1 = Input
144 * Bit 1, Polarity: 0 = No Invert, 1 = Invert
145 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable
146 * Bit 3, Function select: 0 = GPI/O, 1 = LED
147 * Bit 4-6 (Reserved)
148 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
149 */
150 write_io_cr(0xE3, reg);
151}
152
153static inline void wdt_timer_units(unsigned char new_units)
154{
155 /* -- Watchdog timer units --
156 * Bit 0-6 (Reserved)
157 * Bit 7, WDT Time-out Value Units Select
158 * (0 = Minutes, 1 = Seconds)
159 */
160 write_io_cr(0xF1, new_units);
161}
162
163static inline void wdt_timeout_value(unsigned char new_timeout)
164{
165 /* -- Watchdog Timer Time-out Value --
166 * Bit 0-7 Binary coded units (0=Disabled, 1..255)
167 */
168 write_io_cr(0xF2, new_timeout);
169}
170
171static inline void wdt_timer_conf(unsigned char conf)
172{
173 /* -- Watchdog timer configuration --
174 * Bit 0 Joystick enable: 0* = No Reset, 1 = Reset WDT upon
175 * Gameport I/O
176 * Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
177 * Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
178 * Bit 3 Reset the timer
179 * (Wrong in SMsC documentation? Given as: PowerLED Timout
180 * Enabled)
181 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
182 * 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
183 */
184 write_io_cr(0xF3, conf);
185}
186
187static inline void wdt_timer_ctrl(unsigned char reg)
188{
189 /* -- Watchdog timer control --
190 * Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occurred
191 * Bit 1 Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz
192 * Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning)
193 * Bit 3 P20 Force Timeout enabled:
194 * 0 = P20 activity does not generate the WD timeout event
195 * 1 = P20 Allows rising edge of P20, from the keyboard
196 * controller, to force the WD timeout event.
197 * Bit 4 (Reserved)
198 * -- Soft power management --
199 * Bit 5 Stop Counter: 1 = Stop software power down counter
200 * set via register 0xB8, (self-cleaning)
201 * (Upon read: 0 = Counter running, 1 = Counter stopped)
202 * Bit 6 Restart Counter: 1 = Restart software power down counter
203 * set via register 0xB8, (self-cleaning)
204 * Bit 7 SPOFF: 1 = Force software power down (self-cleaning)
205 */
206 write_io_cr(0xF4, reg);
207}
208
209/* -- Higher level functions ------------------------------------*/
210
211/* initialize watchdog */
212
213static void wb_smsc_wdt_initialize(void)
214{
215 unsigned char old;
216
217 spin_lock(&io_lock);
218 open_io_config();
219 select_io_device(IODEV_NO);
220
221 /* enable the watchdog */
222 gpio_bit13(0x08); /* Select pin 80 = LED not GPIO */
223 gpio_bit12(0x0A); /* Set pin 79 = WDT not
224 GPIO/Output/Polarity=Invert */
225 /* disable the timeout */
226 wdt_timeout_value(0);
227
228 /* reset control register */
229 wdt_timer_ctrl(0x00);
230
231 /* reset configuration register */
232 wdt_timer_conf(0x00);
233
234 /* read old (timer units) register */
235 old = read_io_cr(0xF1) & 0x7F;
236 if (unit == UNIT_SECOND)
237 old |= 0x80; /* set to seconds */
238
239 /* set the watchdog timer units */
240 wdt_timer_units(old);
241
242 close_io_config();
243 spin_unlock(&io_lock);
244}
245
246/* shutdown the watchdog */
247
248static void wb_smsc_wdt_shutdown(void)
249{
250 spin_lock(&io_lock);
251 open_io_config();
252 select_io_device(IODEV_NO);
253
254 /* disable the watchdog */
255 gpio_bit13(0x09);
256 gpio_bit12(0x09);
257
258 /* reset watchdog config register */
259 wdt_timer_conf(0x00);
260
261 /* reset watchdog control register */
262 wdt_timer_ctrl(0x00);
263
264 /* disable timeout */
265 wdt_timeout_value(0x00);
266
267 close_io_config();
268 spin_unlock(&io_lock);
269}
270
271/* set timeout => enable watchdog */
272
273static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
274{
275 spin_lock(&io_lock);
276 open_io_config();
277 select_io_device(IODEV_NO);
278
279 /* set Power LED to blink, if we enable the timeout */
280 wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02);
281
282 /* set timeout value */
283 wdt_timeout_value(new_timeout);
284
285 close_io_config();
286 spin_unlock(&io_lock);
287}
288
289/* get timeout */
290
291static unsigned char wb_smsc_wdt_get_timeout(void)
292{
293 unsigned char set_timeout;
294
295 spin_lock(&io_lock);
296 open_io_config();
297 select_io_device(IODEV_NO);
298 set_timeout = read_io_cr(0xF2);
299 close_io_config();
300 spin_unlock(&io_lock);
301
302 return set_timeout;
303}
304
305/* disable watchdog */
306
307static void wb_smsc_wdt_disable(void)
308{
309 /* set the timeout to 0 to disable the watchdog */
310 wb_smsc_wdt_set_timeout(0);
311}
312
313/* enable watchdog by setting the current timeout */
314
315static void wb_smsc_wdt_enable(void)
316{
317 /* set the current timeout... */
318 wb_smsc_wdt_set_timeout(timeout);
319}
320
321/* reset the timer */
322
323static void wb_smsc_wdt_reset_timer(void)
324{
325 spin_lock(&io_lock);
326 open_io_config();
327 select_io_device(IODEV_NO);
328
329 /* reset the timer */
330 wdt_timeout_value(timeout);
331 wdt_timer_conf(0x08);
332
333 close_io_config();
334 spin_unlock(&io_lock);
335}
336
337/* return, if the watchdog is enabled (timeout is set...) */
338
339static int wb_smsc_wdt_status(void)
340{
341 return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING;
342}
343
344
345/* -- File operations -------------------------------------------*/
346
347/* open => enable watchdog and set initial timeout */
348
349static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
350{
351 /* /dev/watchdog can only be opened once */
352
353 if (test_and_set_bit(0, &timer_enabled))
354 return -EBUSY;
355
356 if (nowayout)
357 __module_get(THIS_MODULE);
358
359 /* Reload and activate timer */
360 wb_smsc_wdt_enable();
361
362 pr_info("Watchdog enabled. Timeout set to %d %s\n",
363 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
364
365 return stream_open(inode, file);
366}
367
368/* close => shut off the timer */
369
370static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
371{
372 /* Shut off the timer. */
373
374 if (expect_close == 42) {
375 wb_smsc_wdt_disable();
376 pr_info("Watchdog disabled, sleeping again...\n");
377 } else {
378 pr_crit("Unexpected close, not stopping watchdog!\n");
379 wb_smsc_wdt_reset_timer();
380 }
381
382 clear_bit(0, &timer_enabled);
383 expect_close = 0;
384 return 0;
385}
386
387/* write => update the timer to keep the machine alive */
388
389static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data,
390 size_t len, loff_t *ppos)
391{
392 /* See if we got the magic character 'V' and reload the timer */
393 if (len) {
394 if (!nowayout) {
395 size_t i;
396
397 /* reset expect flag */
398 expect_close = 0;
399
400 /* scan to see whether or not we got the
401 magic character */
402 for (i = 0; i != len; i++) {
403 char c;
404 if (get_user(c, data + i))
405 return -EFAULT;
406 if (c == 'V')
407 expect_close = 42;
408 }
409 }
410
411 /* someone wrote to us, we should reload the timer */
412 wb_smsc_wdt_reset_timer();
413 }
414 return len;
415}
416
417/* ioctl => control interface */
418
419static long wb_smsc_wdt_ioctl(struct file *file,
420 unsigned int cmd, unsigned long arg)
421{
422 int new_timeout;
423
424 union {
425 struct watchdog_info __user *ident;
426 int __user *i;
427 } uarg;
428
429 static const struct watchdog_info ident = {
430 .options = WDIOF_KEEPALIVEPING |
431 WDIOF_SETTIMEOUT |
432 WDIOF_MAGICCLOSE,
433 .firmware_version = 0,
434 .identity = "SMsC 37B787 Watchdog",
435 };
436
437 uarg.i = (int __user *)arg;
438
439 switch (cmd) {
440 case WDIOC_GETSUPPORT:
441 return copy_to_user(uarg.ident, &ident, sizeof(ident))
442 ? -EFAULT : 0;
443 case WDIOC_GETSTATUS:
444 return put_user(wb_smsc_wdt_status(), uarg.i);
445 case WDIOC_GETBOOTSTATUS:
446 return put_user(0, uarg.i);
447 case WDIOC_SETOPTIONS:
448 {
449 int options, retval = -EINVAL;
450
451 if (get_user(options, uarg.i))
452 return -EFAULT;
453
454 if (options & WDIOS_DISABLECARD) {
455 wb_smsc_wdt_disable();
456 retval = 0;
457 }
458 if (options & WDIOS_ENABLECARD) {
459 wb_smsc_wdt_enable();
460 retval = 0;
461 }
462 return retval;
463 }
464 case WDIOC_KEEPALIVE:
465 wb_smsc_wdt_reset_timer();
466 return 0;
467 case WDIOC_SETTIMEOUT:
468 if (get_user(new_timeout, uarg.i))
469 return -EFAULT;
470 /* the API states this is given in secs */
471 if (unit == UNIT_MINUTE)
472 new_timeout /= 60;
473 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
474 return -EINVAL;
475 timeout = new_timeout;
476 wb_smsc_wdt_set_timeout(timeout);
477 fallthrough; /* and return the new timeout */
478 case WDIOC_GETTIMEOUT:
479 new_timeout = timeout;
480 if (unit == UNIT_MINUTE)
481 new_timeout *= 60;
482 return put_user(new_timeout, uarg.i);
483 default:
484 return -ENOTTY;
485 }
486}
487
488/* -- Notifier functions -----------------------------------------*/
489
490static int wb_smsc_wdt_notify_sys(struct notifier_block *this,
491 unsigned long code, void *unused)
492{
493 if (code == SYS_DOWN || code == SYS_HALT) {
494 /* set timeout to 0, to avoid possible race-condition */
495 timeout = 0;
496 wb_smsc_wdt_disable();
497 }
498 return NOTIFY_DONE;
499}
500
501/* -- Module's structures ---------------------------------------*/
502
503static const struct file_operations wb_smsc_wdt_fops = {
504 .owner = THIS_MODULE,
505 .write = wb_smsc_wdt_write,
506 .unlocked_ioctl = wb_smsc_wdt_ioctl,
507 .compat_ioctl = compat_ptr_ioctl,
508 .open = wb_smsc_wdt_open,
509 .release = wb_smsc_wdt_release,
510};
511
512static struct notifier_block wb_smsc_wdt_notifier = {
513 .notifier_call = wb_smsc_wdt_notify_sys,
514};
515
516static struct miscdevice wb_smsc_wdt_miscdev = {
517 .minor = WATCHDOG_MINOR,
518 .name = "watchdog",
519 .fops = &wb_smsc_wdt_fops,
520};
521
522/* -- Module init functions -------------------------------------*/
523
524/* module's "constructor" */
525
526static int __init wb_smsc_wdt_init(void)
527{
528 int ret;
529
530 pr_info("SMsC 37B787 watchdog component driver "
531 VERSION " initialising...\n");
532
533 if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
534 pr_err("Unable to register IO port %#x\n", IOPORT);
535 ret = -EBUSY;
536 goto out_pnp;
537 }
538
539 /* set new maximum, if it's too big */
540 if (timeout > MAX_TIMEOUT)
541 timeout = MAX_TIMEOUT;
542
543 /* init the watchdog timer */
544 wb_smsc_wdt_initialize();
545
546 ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
547 if (ret) {
548 pr_err("Unable to register reboot notifier err = %d\n", ret);
549 goto out_io;
550 }
551
552 ret = misc_register(&wb_smsc_wdt_miscdev);
553 if (ret) {
554 pr_err("Unable to register miscdev on minor %d\n",
555 WATCHDOG_MINOR);
556 goto out_rbt;
557 }
558
559 /* output info */
560 pr_info("Timeout set to %d %s\n",
561 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
562 pr_info("Watchdog initialized and sleeping (nowayout=%d)...\n",
563 nowayout);
564out_clean:
565 return ret;
566
567out_rbt:
568 unregister_reboot_notifier(&wb_smsc_wdt_notifier);
569
570out_io:
571 release_region(IOPORT, IOPORT_SIZE);
572
573out_pnp:
574 goto out_clean;
575}
576
577/* module's "destructor" */
578
579static void __exit wb_smsc_wdt_exit(void)
580{
581 /* Stop the timer before we leave */
582 if (!nowayout) {
583 wb_smsc_wdt_shutdown();
584 pr_info("Watchdog disabled\n");
585 }
586
587 misc_deregister(&wb_smsc_wdt_miscdev);
588 unregister_reboot_notifier(&wb_smsc_wdt_notifier);
589 release_region(IOPORT, IOPORT_SIZE);
590
591 pr_info("SMsC 37B787 watchdog component driver removed\n");
592}
593
594module_init(wb_smsc_wdt_init);
595module_exit(wb_smsc_wdt_exit);
596
597MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
598MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version "
599 VERSION ")");
600MODULE_LICENSE("GPL");
601
602#ifdef SMSC_SUPPORT_MINUTES
603module_param(unit, int, 0);
604MODULE_PARM_DESC(unit,
605 "set unit to use, 0=seconds or 1=minutes, default is 0");
606#endif
607
608module_param(timeout, int, 0);
609MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");
610
611module_param(nowayout, bool, 0);
612MODULE_PARM_DESC(nowayout,
613 "Watchdog cannot be stopped once started (default="
614 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1/*
2 * SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
3 *
4 * Based on acquirewdt.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * and some other existing drivers
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 authors do NOT admit liability nor provide warranty for
13 * any of this software. This material is provided "AS-IS" in
14 * the hope that it may be useful for others.
15 *
16 * (C) Copyright 2003-2006 Sven Anders <anders@anduras.de>
17 *
18 * History:
19 * 2003 - Created version 1.0 for Linux 2.4.x.
20 * 2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE
21 * features. Released version 1.1
22 *
23 * Theory of operation:
24 *
25 * A Watchdog Timer (WDT) is a hardware circuit that can
26 * reset the computer system in case of a software fault.
27 * You probably knew that already.
28 *
29 * Usually a userspace daemon will notify the kernel WDT driver
30 * via the /dev/watchdog special device file that userspace is
31 * still alive, at regular intervals. When such a notification
32 * occurs, the driver will usually tell the hardware watchdog
33 * that everything is in order, and that the watchdog should wait
34 * for yet another little while to reset the system.
35 * If userspace fails (RAM error, kernel bug, whatever), the
36 * notifications cease to occur, and the hardware watchdog will
37 * reset the system (causing a reboot) after the timeout occurs.
38 *
39 * Create device with:
40 * mknod /dev/watchdog c 10 130
41 *
42 * For an example userspace keep-alive daemon, see:
43 * Documentation/watchdog/wdt.txt
44 */
45
46#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47
48#include <linux/module.h>
49#include <linux/moduleparam.h>
50#include <linux/types.h>
51#include <linux/miscdevice.h>
52#include <linux/watchdog.h>
53#include <linux/delay.h>
54#include <linux/fs.h>
55#include <linux/ioport.h>
56#include <linux/notifier.h>
57#include <linux/reboot.h>
58#include <linux/init.h>
59#include <linux/spinlock.h>
60#include <linux/io.h>
61#include <linux/uaccess.h>
62
63
64/* enable support for minutes as units? */
65/* (does not always work correctly, so disabled by default!) */
66#define SMSC_SUPPORT_MINUTES
67#undef SMSC_SUPPORT_MINUTES
68
69#define MAX_TIMEOUT 255
70
71#define UNIT_SECOND 0
72#define UNIT_MINUTE 1
73
74#define VERSION "1.1"
75
76#define IOPORT 0x3F0
77#define IOPORT_SIZE 2
78#define IODEV_NO 8
79
80static int unit = UNIT_SECOND; /* timer's unit */
81static int timeout = 60; /* timeout value: default is 60 "units" */
82static unsigned long timer_enabled; /* is the timer enabled? */
83
84static char expect_close; /* is the close expected? */
85
86static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */
87
88static bool nowayout = WATCHDOG_NOWAYOUT;
89
90/* -- Low level function ----------------------------------------*/
91
92/* unlock the IO chip */
93
94static inline void open_io_config(void)
95{
96 outb(0x55, IOPORT);
97 mdelay(1);
98 outb(0x55, IOPORT);
99}
100
101/* lock the IO chip */
102static inline void close_io_config(void)
103{
104 outb(0xAA, IOPORT);
105}
106
107/* select the IO device */
108static inline void select_io_device(unsigned char devno)
109{
110 outb(0x07, IOPORT);
111 outb(devno, IOPORT+1);
112}
113
114/* write to the control register */
115static inline void write_io_cr(unsigned char reg, unsigned char data)
116{
117 outb(reg, IOPORT);
118 outb(data, IOPORT+1);
119}
120
121/* read from the control register */
122static inline char read_io_cr(unsigned char reg)
123{
124 outb(reg, IOPORT);
125 return inb(IOPORT+1);
126}
127
128/* -- Medium level functions ------------------------------------*/
129
130static inline void gpio_bit12(unsigned char reg)
131{
132 /* -- General Purpose I/O Bit 1.2 --
133 * Bit 0, In/Out: 0 = Output, 1 = Input
134 * Bit 1, Polarity: 0 = No Invert, 1 = Invert
135 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable
136 * Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17,
137 * 11 = Either Edge Triggered Intr. 2
138 * Bit 5/6 (Reserved)
139 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
140 */
141 write_io_cr(0xE2, reg);
142}
143
144static inline void gpio_bit13(unsigned char reg)
145{
146 /* -- General Purpose I/O Bit 1.3 --
147 * Bit 0, In/Out: 0 = Output, 1 = Input
148 * Bit 1, Polarity: 0 = No Invert, 1 = Invert
149 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable
150 * Bit 3, Function select: 0 = GPI/O, 1 = LED
151 * Bit 4-6 (Reserved)
152 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
153 */
154 write_io_cr(0xE3, reg);
155}
156
157static inline void wdt_timer_units(unsigned char new_units)
158{
159 /* -- Watchdog timer units --
160 * Bit 0-6 (Reserved)
161 * Bit 7, WDT Time-out Value Units Select
162 * (0 = Minutes, 1 = Seconds)
163 */
164 write_io_cr(0xF1, new_units);
165}
166
167static inline void wdt_timeout_value(unsigned char new_timeout)
168{
169 /* -- Watchdog Timer Time-out Value --
170 * Bit 0-7 Binary coded units (0=Disabled, 1..255)
171 */
172 write_io_cr(0xF2, new_timeout);
173}
174
175static inline void wdt_timer_conf(unsigned char conf)
176{
177 /* -- Watchdog timer configuration --
178 * Bit 0 Joystick enable: 0* = No Reset, 1 = Reset WDT upon
179 * Gameport I/O
180 * Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
181 * Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
182 * Bit 3 Reset the timer
183 * (Wrong in SMsC documentation? Given as: PowerLED Timout
184 * Enabled)
185 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
186 * 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
187 */
188 write_io_cr(0xF3, conf);
189}
190
191static inline void wdt_timer_ctrl(unsigned char reg)
192{
193 /* -- Watchdog timer control --
194 * Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occurred
195 * Bit 1 Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz
196 * Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning)
197 * Bit 3 P20 Force Timeout enabled:
198 * 0 = P20 activity does not generate the WD timeout event
199 * 1 = P20 Allows rising edge of P20, from the keyboard
200 * controller, to force the WD timeout event.
201 * Bit 4 (Reserved)
202 * -- Soft power management --
203 * Bit 5 Stop Counter: 1 = Stop software power down counter
204 * set via register 0xB8, (self-cleaning)
205 * (Upon read: 0 = Counter running, 1 = Counter stopped)
206 * Bit 6 Restart Counter: 1 = Restart software power down counter
207 * set via register 0xB8, (self-cleaning)
208 * Bit 7 SPOFF: 1 = Force software power down (self-cleaning)
209 */
210 write_io_cr(0xF4, reg);
211}
212
213/* -- Higher level functions ------------------------------------*/
214
215/* initialize watchdog */
216
217static void wb_smsc_wdt_initialize(void)
218{
219 unsigned char old;
220
221 spin_lock(&io_lock);
222 open_io_config();
223 select_io_device(IODEV_NO);
224
225 /* enable the watchdog */
226 gpio_bit13(0x08); /* Select pin 80 = LED not GPIO */
227 gpio_bit12(0x0A); /* Set pin 79 = WDT not
228 GPIO/Output/Polarity=Invert */
229 /* disable the timeout */
230 wdt_timeout_value(0);
231
232 /* reset control register */
233 wdt_timer_ctrl(0x00);
234
235 /* reset configuration register */
236 wdt_timer_conf(0x00);
237
238 /* read old (timer units) register */
239 old = read_io_cr(0xF1) & 0x7F;
240 if (unit == UNIT_SECOND)
241 old |= 0x80; /* set to seconds */
242
243 /* set the watchdog timer units */
244 wdt_timer_units(old);
245
246 close_io_config();
247 spin_unlock(&io_lock);
248}
249
250/* shutdown the watchdog */
251
252static void wb_smsc_wdt_shutdown(void)
253{
254 spin_lock(&io_lock);
255 open_io_config();
256 select_io_device(IODEV_NO);
257
258 /* disable the watchdog */
259 gpio_bit13(0x09);
260 gpio_bit12(0x09);
261
262 /* reset watchdog config register */
263 wdt_timer_conf(0x00);
264
265 /* reset watchdog control register */
266 wdt_timer_ctrl(0x00);
267
268 /* disable timeout */
269 wdt_timeout_value(0x00);
270
271 close_io_config();
272 spin_unlock(&io_lock);
273}
274
275/* set timeout => enable watchdog */
276
277static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
278{
279 spin_lock(&io_lock);
280 open_io_config();
281 select_io_device(IODEV_NO);
282
283 /* set Power LED to blink, if we enable the timeout */
284 wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02);
285
286 /* set timeout value */
287 wdt_timeout_value(new_timeout);
288
289 close_io_config();
290 spin_unlock(&io_lock);
291}
292
293/* get timeout */
294
295static unsigned char wb_smsc_wdt_get_timeout(void)
296{
297 unsigned char set_timeout;
298
299 spin_lock(&io_lock);
300 open_io_config();
301 select_io_device(IODEV_NO);
302 set_timeout = read_io_cr(0xF2);
303 close_io_config();
304 spin_unlock(&io_lock);
305
306 return set_timeout;
307}
308
309/* disable watchdog */
310
311static void wb_smsc_wdt_disable(void)
312{
313 /* set the timeout to 0 to disable the watchdog */
314 wb_smsc_wdt_set_timeout(0);
315}
316
317/* enable watchdog by setting the current timeout */
318
319static void wb_smsc_wdt_enable(void)
320{
321 /* set the current timeout... */
322 wb_smsc_wdt_set_timeout(timeout);
323}
324
325/* reset the timer */
326
327static void wb_smsc_wdt_reset_timer(void)
328{
329 spin_lock(&io_lock);
330 open_io_config();
331 select_io_device(IODEV_NO);
332
333 /* reset the timer */
334 wdt_timeout_value(timeout);
335 wdt_timer_conf(0x08);
336
337 close_io_config();
338 spin_unlock(&io_lock);
339}
340
341/* return, if the watchdog is enabled (timeout is set...) */
342
343static int wb_smsc_wdt_status(void)
344{
345 return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING;
346}
347
348
349/* -- File operations -------------------------------------------*/
350
351/* open => enable watchdog and set initial timeout */
352
353static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
354{
355 /* /dev/watchdog can only be opened once */
356
357 if (test_and_set_bit(0, &timer_enabled))
358 return -EBUSY;
359
360 if (nowayout)
361 __module_get(THIS_MODULE);
362
363 /* Reload and activate timer */
364 wb_smsc_wdt_enable();
365
366 pr_info("Watchdog enabled. Timeout set to %d %s\n",
367 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
368
369 return nonseekable_open(inode, file);
370}
371
372/* close => shut off the timer */
373
374static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
375{
376 /* Shut off the timer. */
377
378 if (expect_close == 42) {
379 wb_smsc_wdt_disable();
380 pr_info("Watchdog disabled, sleeping again...\n");
381 } else {
382 pr_crit("Unexpected close, not stopping watchdog!\n");
383 wb_smsc_wdt_reset_timer();
384 }
385
386 clear_bit(0, &timer_enabled);
387 expect_close = 0;
388 return 0;
389}
390
391/* write => update the timer to keep the machine alive */
392
393static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data,
394 size_t len, loff_t *ppos)
395{
396 /* See if we got the magic character 'V' and reload the timer */
397 if (len) {
398 if (!nowayout) {
399 size_t i;
400
401 /* reset expect flag */
402 expect_close = 0;
403
404 /* scan to see whether or not we got the
405 magic character */
406 for (i = 0; i != len; i++) {
407 char c;
408 if (get_user(c, data + i))
409 return -EFAULT;
410 if (c == 'V')
411 expect_close = 42;
412 }
413 }
414
415 /* someone wrote to us, we should reload the timer */
416 wb_smsc_wdt_reset_timer();
417 }
418 return len;
419}
420
421/* ioctl => control interface */
422
423static long wb_smsc_wdt_ioctl(struct file *file,
424 unsigned int cmd, unsigned long arg)
425{
426 int new_timeout;
427
428 union {
429 struct watchdog_info __user *ident;
430 int __user *i;
431 } uarg;
432
433 static const struct watchdog_info ident = {
434 .options = WDIOF_KEEPALIVEPING |
435 WDIOF_SETTIMEOUT |
436 WDIOF_MAGICCLOSE,
437 .firmware_version = 0,
438 .identity = "SMsC 37B787 Watchdog",
439 };
440
441 uarg.i = (int __user *)arg;
442
443 switch (cmd) {
444 case WDIOC_GETSUPPORT:
445 return copy_to_user(uarg.ident, &ident, sizeof(ident))
446 ? -EFAULT : 0;
447 case WDIOC_GETSTATUS:
448 return put_user(wb_smsc_wdt_status(), uarg.i);
449 case WDIOC_GETBOOTSTATUS:
450 return put_user(0, uarg.i);
451 case WDIOC_SETOPTIONS:
452 {
453 int options, retval = -EINVAL;
454
455 if (get_user(options, uarg.i))
456 return -EFAULT;
457
458 if (options & WDIOS_DISABLECARD) {
459 wb_smsc_wdt_disable();
460 retval = 0;
461 }
462 if (options & WDIOS_ENABLECARD) {
463 wb_smsc_wdt_enable();
464 retval = 0;
465 }
466 return retval;
467 }
468 case WDIOC_KEEPALIVE:
469 wb_smsc_wdt_reset_timer();
470 return 0;
471 case WDIOC_SETTIMEOUT:
472 if (get_user(new_timeout, uarg.i))
473 return -EFAULT;
474 /* the API states this is given in secs */
475 if (unit == UNIT_MINUTE)
476 new_timeout /= 60;
477 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
478 return -EINVAL;
479 timeout = new_timeout;
480 wb_smsc_wdt_set_timeout(timeout);
481 /* fall through and return the new timeout... */
482 case WDIOC_GETTIMEOUT:
483 new_timeout = timeout;
484 if (unit == UNIT_MINUTE)
485 new_timeout *= 60;
486 return put_user(new_timeout, uarg.i);
487 default:
488 return -ENOTTY;
489 }
490}
491
492/* -- Notifier funtions -----------------------------------------*/
493
494static int wb_smsc_wdt_notify_sys(struct notifier_block *this,
495 unsigned long code, void *unused)
496{
497 if (code == SYS_DOWN || code == SYS_HALT) {
498 /* set timeout to 0, to avoid possible race-condition */
499 timeout = 0;
500 wb_smsc_wdt_disable();
501 }
502 return NOTIFY_DONE;
503}
504
505/* -- Module's structures ---------------------------------------*/
506
507static const struct file_operations wb_smsc_wdt_fops = {
508 .owner = THIS_MODULE,
509 .llseek = no_llseek,
510 .write = wb_smsc_wdt_write,
511 .unlocked_ioctl = wb_smsc_wdt_ioctl,
512 .open = wb_smsc_wdt_open,
513 .release = wb_smsc_wdt_release,
514};
515
516static struct notifier_block wb_smsc_wdt_notifier = {
517 .notifier_call = wb_smsc_wdt_notify_sys,
518};
519
520static struct miscdevice wb_smsc_wdt_miscdev = {
521 .minor = WATCHDOG_MINOR,
522 .name = "watchdog",
523 .fops = &wb_smsc_wdt_fops,
524};
525
526/* -- Module init functions -------------------------------------*/
527
528/* module's "constructor" */
529
530static int __init wb_smsc_wdt_init(void)
531{
532 int ret;
533
534 pr_info("SMsC 37B787 watchdog component driver "
535 VERSION " initialising...\n");
536
537 if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
538 pr_err("Unable to register IO port %#x\n", IOPORT);
539 ret = -EBUSY;
540 goto out_pnp;
541 }
542
543 /* set new maximum, if it's too big */
544 if (timeout > MAX_TIMEOUT)
545 timeout = MAX_TIMEOUT;
546
547 /* init the watchdog timer */
548 wb_smsc_wdt_initialize();
549
550 ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
551 if (ret) {
552 pr_err("Unable to register reboot notifier err = %d\n", ret);
553 goto out_io;
554 }
555
556 ret = misc_register(&wb_smsc_wdt_miscdev);
557 if (ret) {
558 pr_err("Unable to register miscdev on minor %d\n",
559 WATCHDOG_MINOR);
560 goto out_rbt;
561 }
562
563 /* output info */
564 pr_info("Timeout set to %d %s\n",
565 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
566 pr_info("Watchdog initialized and sleeping (nowayout=%d)...\n",
567 nowayout);
568out_clean:
569 return ret;
570
571out_rbt:
572 unregister_reboot_notifier(&wb_smsc_wdt_notifier);
573
574out_io:
575 release_region(IOPORT, IOPORT_SIZE);
576
577out_pnp:
578 goto out_clean;
579}
580
581/* module's "destructor" */
582
583static void __exit wb_smsc_wdt_exit(void)
584{
585 /* Stop the timer before we leave */
586 if (!nowayout) {
587 wb_smsc_wdt_shutdown();
588 pr_info("Watchdog disabled\n");
589 }
590
591 misc_deregister(&wb_smsc_wdt_miscdev);
592 unregister_reboot_notifier(&wb_smsc_wdt_notifier);
593 release_region(IOPORT, IOPORT_SIZE);
594
595 pr_info("SMsC 37B787 watchdog component driver removed\n");
596}
597
598module_init(wb_smsc_wdt_init);
599module_exit(wb_smsc_wdt_exit);
600
601MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
602MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version "
603 VERSION ")");
604MODULE_LICENSE("GPL");
605
606#ifdef SMSC_SUPPORT_MINUTES
607module_param(unit, int, 0);
608MODULE_PARM_DESC(unit,
609 "set unit to use, 0=seconds or 1=minutes, default is 0");
610#endif
611
612module_param(timeout, int, 0);
613MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");
614
615module_param(nowayout, bool, 0);
616MODULE_PARM_DESC(nowayout,
617 "Watchdog cannot be stopped once started (default="
618 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");