1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
4 *
5 * This code is based on wdt.c with original copyright.
6 *
7 * (C) Copyright 2006 Sven Anders, <anders@anduras.de>
8 * and Marcus Junker, <junker@anduras.de>
9 *
10 * Neither Sven Anders, Marcus Junker nor ANDURAS AG
11 * admit liability nor provide warranty for any of this software.
12 * This material is provided "AS-IS" and at no charge.
13 *
14 * Release 1.1
15 */
16
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/module.h>
20#include <linux/types.h>
21#include <linux/miscdevice.h>
22#include <linux/watchdog.h>
23#include <linux/ioport.h>
24#include <linux/delay.h>
25#include <linux/notifier.h>
26#include <linux/fs.h>
27#include <linux/reboot.h>
28#include <linux/init.h>
29#include <linux/spinlock.h>
30#include <linux/moduleparam.h>
31#include <linux/io.h>
32#include <linux/uaccess.h>
33
34
35/* #define DEBUG 1 */
36
37#define DEFAULT_TIMEOUT 1 /* 1 minute */
38#define MAX_TIMEOUT 255
39
40#define VERSION "1.1"
41#define MODNAME "pc87413 WDT"
42#define DPFX MODNAME " - DEBUG: "
43
44#define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */
45#define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1)
46#define SWC_LDN 0x04
47#define SIOCFG2 0x22 /* Serial IO register */
48#define WDCTL 0x10 /* Watchdog-Timer-Control-Register */
49#define WDTO 0x11 /* Watchdog timeout register */
50#define WDCFG 0x12 /* Watchdog config register */
51
52#define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
53
54static int io = IO_DEFAULT;
55static int swc_base_addr = -1;
56
57static int timeout = DEFAULT_TIMEOUT; /* timeout value */
58static unsigned long timer_enabled; /* is the timer enabled? */
59
60static char expect_close; /* is the close expected? */
61
62static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */
63
64static bool nowayout = WATCHDOG_NOWAYOUT;
65
66/* -- Low level function ----------------------------------------*/
67
68/* Select pins for Watchdog output */
69
70static inline void pc87413_select_wdt_out(void)
71{
72 unsigned int cr_data = 0;
73
74 /* Step 1: Select multiple pin,pin55,as WDT output */
75
76 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
77
78 cr_data = inb(WDT_DATA_IO_PORT);
79
80 cr_data |= 0x80; /* Set Bit7 to 1*/
81 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
82
83 outb_p(value: cr_data, WDT_DATA_IO_PORT);
84
85#ifdef DEBUG
86 pr_info(DPFX
87 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
88 cr_data);
89#endif
90}
91
92/* Enable SWC functions */
93
94static inline void pc87413_enable_swc(void)
95{
96 unsigned int cr_data = 0;
97
98 /* Step 2: Enable SWC functions */
99
100 outb_p(value: 0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */
101 outb_p(SWC_LDN, WDT_DATA_IO_PORT);
102
103 outb_p(value: 0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */
104 cr_data = inb(WDT_DATA_IO_PORT);
105 cr_data |= 0x01; /* Set Bit0 to 1 */
106 outb_p(value: 0x30, WDT_INDEX_IO_PORT);
107 outb_p(value: cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */
108
109#ifdef DEBUG
110 pr_info(DPFX "pc87413 - Enable SWC functions\n");
111#endif
112}
113
114/* Read SWC I/O base address */
115
116static void pc87413_get_swc_base_addr(void)
117{
118 unsigned char addr_l, addr_h = 0;
119
120 /* Step 3: Read SWC I/O Base Address */
121
122 outb_p(value: 0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */
123 addr_h = inb(WDT_DATA_IO_PORT);
124
125 outb_p(value: 0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */
126
127 addr_l = inb(WDT_DATA_IO_PORT);
128
129 swc_base_addr = (addr_h << 8) + addr_l;
130#ifdef DEBUG
131 pr_info(DPFX
132 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
133 addr_l, addr_h, swc_base_addr);
134#endif
135}
136
137/* Select Bank 3 of SWC */
138
139static inline void pc87413_swc_bank3(void)
140{
141 /* Step 4: Select Bank3 of SWC */
142 outb_p(inb(port: swc_base_addr + 0x0f) | 0x03, port: swc_base_addr + 0x0f);
143#ifdef DEBUG
144 pr_info(DPFX "Select Bank3 of SWC\n");
145#endif
146}
147
148/* Set watchdog timeout to x minutes */
149
150static inline void pc87413_programm_wdto(char pc87413_time)
151{
152 /* Step 5: Programm WDTO, Twd. */
153 outb_p(value: pc87413_time, port: swc_base_addr + WDTO);
154#ifdef DEBUG
155 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
156#endif
157}
158
159/* Enable WDEN */
160
161static inline void pc87413_enable_wden(void)
162{
163 /* Step 6: Enable WDEN */
164 outb_p(inb(port: swc_base_addr + WDCTL) | 0x01, port: swc_base_addr + WDCTL);
165#ifdef DEBUG
166 pr_info(DPFX "Enable WDEN\n");
167#endif
168}
169
170/* Enable SW_WD_TREN */
171static inline void pc87413_enable_sw_wd_tren(void)
172{
173 /* Enable SW_WD_TREN */
174 outb_p(inb(port: swc_base_addr + WDCFG) | 0x80, port: swc_base_addr + WDCFG);
175#ifdef DEBUG
176 pr_info(DPFX "Enable SW_WD_TREN\n");
177#endif
178}
179
180/* Disable SW_WD_TREN */
181
182static inline void pc87413_disable_sw_wd_tren(void)
183{
184 /* Disable SW_WD_TREN */
185 outb_p(inb(port: swc_base_addr + WDCFG) & 0x7f, port: swc_base_addr + WDCFG);
186#ifdef DEBUG
187 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
188#endif
189}
190
191/* Enable SW_WD_TRG */
192
193static inline void pc87413_enable_sw_wd_trg(void)
194{
195 /* Enable SW_WD_TRG */
196 outb_p(inb(port: swc_base_addr + WDCTL) | 0x80, port: swc_base_addr + WDCTL);
197#ifdef DEBUG
198 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
199#endif
200}
201
202/* Disable SW_WD_TRG */
203
204static inline void pc87413_disable_sw_wd_trg(void)
205{
206 /* Disable SW_WD_TRG */
207 outb_p(inb(port: swc_base_addr + WDCTL) & 0x7f, port: swc_base_addr + WDCTL);
208#ifdef DEBUG
209 pr_info(DPFX "Disable SW_WD_TRG\n");
210#endif
211}
212
213/* -- Higher level functions ------------------------------------*/
214
215/* Enable the watchdog */
216
217static void pc87413_enable(void)
218{
219 spin_lock(lock: &io_lock);
220
221 pc87413_swc_bank3();
222 pc87413_programm_wdto(pc87413_time: timeout);
223 pc87413_enable_wden();
224 pc87413_enable_sw_wd_tren();
225 pc87413_enable_sw_wd_trg();
226
227 spin_unlock(lock: &io_lock);
228}
229
230/* Disable the watchdog */
231
232static void pc87413_disable(void)
233{
234 spin_lock(lock: &io_lock);
235
236 pc87413_swc_bank3();
237 pc87413_disable_sw_wd_tren();
238 pc87413_disable_sw_wd_trg();
239 pc87413_programm_wdto(pc87413_time: 0);
240
241 spin_unlock(lock: &io_lock);
242}
243
244/* Refresh the watchdog */
245
246static void pc87413_refresh(void)
247{
248 spin_lock(lock: &io_lock);
249
250 pc87413_swc_bank3();
251 pc87413_disable_sw_wd_tren();
252 pc87413_disable_sw_wd_trg();
253 pc87413_programm_wdto(pc87413_time: timeout);
254 pc87413_enable_wden();
255 pc87413_enable_sw_wd_tren();
256 pc87413_enable_sw_wd_trg();
257
258 spin_unlock(lock: &io_lock);
259}
260
261/* -- File operations -------------------------------------------*/
262
263/**
264 * pc87413_open:
265 * @inode: inode of device
266 * @file: file handle to device
267 *
268 */
269
270static int pc87413_open(struct inode *inode, struct file *file)
271{
272 /* /dev/watchdog can only be opened once */
273
274 if (test_and_set_bit(nr: 0, addr: &timer_enabled))
275 return -EBUSY;
276
277 if (nowayout)
278 __module_get(THIS_MODULE);
279
280 /* Reload and activate timer */
281 pc87413_refresh();
282
283 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
284
285 return stream_open(inode, filp: file);
286}
287
288/**
289 * pc87413_release:
290 * @inode: inode to board
291 * @file: file handle to board
292 *
293 * The watchdog has a configurable API. There is a religious dispute
294 * between people who want their watchdog to be able to shut down and
295 * those who want to be sure if the watchdog manager dies the machine
296 * reboots. In the former case we disable the counters, in the latter
297 * case you have to open it again very soon.
298 */
299
300static int pc87413_release(struct inode *inode, struct file *file)
301{
302 /* Shut off the timer. */
303
304 if (expect_close == 42) {
305 pc87413_disable();
306 pr_info("Watchdog disabled, sleeping again...\n");
307 } else {
308 pr_crit("Unexpected close, not stopping watchdog!\n");
309 pc87413_refresh();
310 }
311 clear_bit(nr: 0, addr: &timer_enabled);
312 expect_close = 0;
313 return 0;
314}
315
316/**
317 * pc87413_status:
318 *
319 * return, if the watchdog is enabled (timeout is set...)
320 */
321
322
323static int pc87413_status(void)
324{
325 return 0; /* currently not supported */
326}
327
328/**
329 * pc87413_write:
330 * @file: file handle to the watchdog
331 * @data: data buffer to write
332 * @len: length in bytes
333 * @ppos: pointer to the position to write. No seeks allowed
334 *
335 * A write to a watchdog device is defined as a keepalive signal. Any
336 * write of data will do, as we we don't define content meaning.
337 */
338
339static ssize_t pc87413_write(struct file *file, const char __user *data,
340 size_t len, loff_t *ppos)
341{
342 /* See if we got the magic character 'V' and reload the timer */
343 if (len) {
344 if (!nowayout) {
345 size_t i;
346
347 /* reset expect flag */
348 expect_close = 0;
349
350 /* scan to see whether or not we got the
351 magic character */
352 for (i = 0; i != len; i++) {
353 char c;
354 if (get_user(c, data + i))
355 return -EFAULT;
356 if (c == 'V')
357 expect_close = 42;
358 }
359 }
360
361 /* someone wrote to us, we should reload the timer */
362 pc87413_refresh();
363 }
364 return len;
365}
366
367/**
368 * pc87413_ioctl:
369 * @file: file handle to the device
370 * @cmd: watchdog command
371 * @arg: argument pointer
372 *
373 * The watchdog API defines a common set of functions for all watchdogs
374 * according to their available features. We only actually usefully support
375 * querying capabilities and current status.
376 */
377
378static long pc87413_ioctl(struct file *file, unsigned int cmd,
379 unsigned long arg)
380{
381 int new_timeout;
382
383 union {
384 struct watchdog_info __user *ident;
385 int __user *i;
386 } uarg;
387
388 static const struct watchdog_info ident = {
389 .options = WDIOF_KEEPALIVEPING |
390 WDIOF_SETTIMEOUT |
391 WDIOF_MAGICCLOSE,
392 .firmware_version = 1,
393 .identity = "PC87413(HF/F) watchdog",
394 };
395
396 uarg.i = (int __user *)arg;
397
398 switch (cmd) {
399 case WDIOC_GETSUPPORT:
400 return copy_to_user(to: uarg.ident, from: &ident,
401 n: sizeof(ident)) ? -EFAULT : 0;
402 case WDIOC_GETSTATUS:
403 return put_user(pc87413_status(), uarg.i);
404 case WDIOC_GETBOOTSTATUS:
405 return put_user(0, uarg.i);
406 case WDIOC_SETOPTIONS:
407 {
408 int options, retval = -EINVAL;
409 if (get_user(options, uarg.i))
410 return -EFAULT;
411 if (options & WDIOS_DISABLECARD) {
412 pc87413_disable();
413 retval = 0;
414 }
415 if (options & WDIOS_ENABLECARD) {
416 pc87413_enable();
417 retval = 0;
418 }
419 return retval;
420 }
421 case WDIOC_KEEPALIVE:
422 pc87413_refresh();
423#ifdef DEBUG
424 pr_info(DPFX "keepalive\n");
425#endif
426 return 0;
427 case WDIOC_SETTIMEOUT:
428 if (get_user(new_timeout, uarg.i))
429 return -EFAULT;
430 /* the API states this is given in secs */
431 new_timeout /= 60;
432 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
433 return -EINVAL;
434 timeout = new_timeout;
435 pc87413_refresh();
436 fallthrough; /* and return the new timeout */
437 case WDIOC_GETTIMEOUT:
438 new_timeout = timeout * 60;
439 return put_user(new_timeout, uarg.i);
440 default:
441 return -ENOTTY;
442 }
443}
444
445/* -- Notifier functions -----------------------------------------*/
446
447/**
448 * pc87413_notify_sys:
449 * @this: our notifier block
450 * @code: the event being reported
451 * @unused: unused
452 *
453 * Our notifier is called on system shutdowns. We want to turn the card
454 * off at reboot otherwise the machine will reboot again during memory
455 * test or worse yet during the following fsck. This would suck, in fact
456 * trust me - if it happens it does suck.
457 */
458
459static int pc87413_notify_sys(struct notifier_block *this,
460 unsigned long code,
461 void *unused)
462{
463 if (code == SYS_DOWN || code == SYS_HALT)
464 /* Turn the card off */
465 pc87413_disable();
466 return NOTIFY_DONE;
467}
468
469/* -- Module's structures ---------------------------------------*/
470
471static const struct file_operations pc87413_fops = {
472 .owner = THIS_MODULE,
473 .write = pc87413_write,
474 .unlocked_ioctl = pc87413_ioctl,
475 .compat_ioctl = compat_ptr_ioctl,
476 .open = pc87413_open,
477 .release = pc87413_release,
478};
479
480static struct notifier_block pc87413_notifier = {
481 .notifier_call = pc87413_notify_sys,
482};
483
484static struct miscdevice pc87413_miscdev = {
485 .minor = WATCHDOG_MINOR,
486 .name = "watchdog",
487 .fops = &pc87413_fops,
488};
489
490/* -- Module init functions -------------------------------------*/
491
492/**
493 * pc87413_init: module's "constructor"
494 *
495 * Set up the WDT watchdog board. All we have to do is grab the
496 * resources we require and bitch if anyone beat us to them.
497 * The open() function will actually kick the board off.
498 */
499
500static int __init pc87413_init(void)
501{
502 int ret;
503
504 pr_info("Version " VERSION " at io 0x%X\n",
505 WDT_INDEX_IO_PORT);
506
507 if (!request_muxed_region(io, 2, MODNAME))
508 return -EBUSY;
509
510 ret = register_reboot_notifier(&pc87413_notifier);
511 if (ret != 0)
512 pr_err("cannot register reboot notifier (err=%d)\n", ret);
513
514 ret = misc_register(misc: &pc87413_miscdev);
515 if (ret != 0) {
516 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
517 WATCHDOG_MINOR, ret);
518 goto reboot_unreg;
519 }
520 pr_info("initialized. timeout=%d min\n", timeout);
521
522 pc87413_select_wdt_out();
523 pc87413_enable_swc();
524 pc87413_get_swc_base_addr();
525
526 if (!request_region(swc_base_addr, 0x20, MODNAME)) {
527 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
528 ret = -EBUSY;
529 goto misc_unreg;
530 }
531
532 pc87413_enable();
533
534 release_region(io, 2);
535 return 0;
536
537misc_unreg:
538 misc_deregister(misc: &pc87413_miscdev);
539reboot_unreg:
540 unregister_reboot_notifier(&pc87413_notifier);
541 release_region(io, 2);
542 return ret;
543}
544
545/**
546 * pc87413_exit: module's "destructor"
547 *
548 * Unload the watchdog. You cannot do this with any file handles open.
549 * If your watchdog is set to continue ticking on close and you unload
550 * it, well it keeps ticking. We won't get the interrupt but the board
551 * will not touch PC memory so all is fine. You just have to load a new
552 * module in 60 seconds or reboot.
553 */
554
555static void __exit pc87413_exit(void)
556{
557 /* Stop the timer before we leave */
558 if (!nowayout) {
559 pc87413_disable();
560 pr_info("Watchdog disabled\n");
561 }
562
563 misc_deregister(misc: &pc87413_miscdev);
564 unregister_reboot_notifier(&pc87413_notifier);
565 release_region(swc_base_addr, 0x20);
566
567 pr_info("watchdog component driver removed\n");
568}
569
570module_init(pc87413_init);
571module_exit(pc87413_exit);
572
573MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
574MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
575MODULE_DESCRIPTION("PC87413 WDT driver");
576MODULE_LICENSE("GPL");
577
578module_param_hw(io, int, ioport, 0);
579MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
580 __MODULE_STRING(IO_DEFAULT) ").");
581
582module_param(timeout, int, 0);
583MODULE_PARM_DESC(timeout,
584 "Watchdog timeout in minutes (default="
585 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
586
587module_param(nowayout, bool, 0);
588MODULE_PARM_DESC(nowayout,
589 "Watchdog cannot be stopped once started (default="
590 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
591
592

source code of linux/drivers/watchdog/pc87413_wdt.c