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 | |
54 | static int io = IO_DEFAULT; |
55 | static int swc_base_addr = -1; |
56 | |
57 | static int timeout = DEFAULT_TIMEOUT; /* timeout value */ |
58 | static unsigned long timer_enabled; /* is the timer enabled? */ |
59 | |
60 | static char expect_close; /* is the close expected? */ |
61 | |
62 | static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */ |
63 | |
64 | static bool nowayout = WATCHDOG_NOWAYOUT; |
65 | |
66 | /* -- Low level function ----------------------------------------*/ |
67 | |
68 | /* Select pins for Watchdog output */ |
69 | |
70 | static 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 | |
94 | static 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 | |
116 | static 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 | |
139 | static 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 | |
150 | static 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 | |
161 | static 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 */ |
171 | static 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 | |
182 | static 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 | |
193 | static 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 | |
204 | static 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 | |
217 | static 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 | |
232 | static 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 | |
246 | static 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 | |
270 | static 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 | |
300 | static 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 | |
323 | static 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 | |
339 | static 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 | |
378 | static 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 | |
459 | static 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 | |
471 | static const struct file_operations pc87413_fops = { |
472 | .owner = THIS_MODULE, |
473 | .llseek = no_llseek, |
474 | .write = pc87413_write, |
475 | .unlocked_ioctl = pc87413_ioctl, |
476 | .compat_ioctl = compat_ptr_ioctl, |
477 | .open = pc87413_open, |
478 | .release = pc87413_release, |
479 | }; |
480 | |
481 | static struct notifier_block pc87413_notifier = { |
482 | .notifier_call = pc87413_notify_sys, |
483 | }; |
484 | |
485 | static struct miscdevice pc87413_miscdev = { |
486 | .minor = WATCHDOG_MINOR, |
487 | .name = "watchdog" , |
488 | .fops = &pc87413_fops, |
489 | }; |
490 | |
491 | /* -- Module init functions -------------------------------------*/ |
492 | |
493 | /** |
494 | * pc87413_init: module's "constructor" |
495 | * |
496 | * Set up the WDT watchdog board. All we have to do is grab the |
497 | * resources we require and bitch if anyone beat us to them. |
498 | * The open() function will actually kick the board off. |
499 | */ |
500 | |
501 | static int __init pc87413_init(void) |
502 | { |
503 | int ret; |
504 | |
505 | pr_info("Version " VERSION " at io 0x%X\n" , |
506 | WDT_INDEX_IO_PORT); |
507 | |
508 | if (!request_muxed_region(io, 2, MODNAME)) |
509 | return -EBUSY; |
510 | |
511 | ret = register_reboot_notifier(&pc87413_notifier); |
512 | if (ret != 0) |
513 | pr_err("cannot register reboot notifier (err=%d)\n" , ret); |
514 | |
515 | ret = misc_register(misc: &pc87413_miscdev); |
516 | if (ret != 0) { |
517 | pr_err("cannot register miscdev on minor=%d (err=%d)\n" , |
518 | WATCHDOG_MINOR, ret); |
519 | goto reboot_unreg; |
520 | } |
521 | pr_info("initialized. timeout=%d min\n" , timeout); |
522 | |
523 | pc87413_select_wdt_out(); |
524 | pc87413_enable_swc(); |
525 | pc87413_get_swc_base_addr(); |
526 | |
527 | if (!request_region(swc_base_addr, 0x20, MODNAME)) { |
528 | pr_err("cannot request SWC region at 0x%x\n" , swc_base_addr); |
529 | ret = -EBUSY; |
530 | goto misc_unreg; |
531 | } |
532 | |
533 | pc87413_enable(); |
534 | |
535 | release_region(io, 2); |
536 | return 0; |
537 | |
538 | misc_unreg: |
539 | misc_deregister(misc: &pc87413_miscdev); |
540 | reboot_unreg: |
541 | unregister_reboot_notifier(&pc87413_notifier); |
542 | release_region(io, 2); |
543 | return ret; |
544 | } |
545 | |
546 | /** |
547 | * pc87413_exit: module's "destructor" |
548 | * |
549 | * Unload the watchdog. You cannot do this with any file handles open. |
550 | * If your watchdog is set to continue ticking on close and you unload |
551 | * it, well it keeps ticking. We won't get the interrupt but the board |
552 | * will not touch PC memory so all is fine. You just have to load a new |
553 | * module in 60 seconds or reboot. |
554 | */ |
555 | |
556 | static void __exit pc87413_exit(void) |
557 | { |
558 | /* Stop the timer before we leave */ |
559 | if (!nowayout) { |
560 | pc87413_disable(); |
561 | pr_info("Watchdog disabled\n" ); |
562 | } |
563 | |
564 | misc_deregister(misc: &pc87413_miscdev); |
565 | unregister_reboot_notifier(&pc87413_notifier); |
566 | release_region(swc_base_addr, 0x20); |
567 | |
568 | pr_info("watchdog component driver removed\n" ); |
569 | } |
570 | |
571 | module_init(pc87413_init); |
572 | module_exit(pc87413_exit); |
573 | |
574 | MODULE_AUTHOR("Sven Anders <anders@anduras.de>" ); |
575 | MODULE_AUTHOR("Marcus Junker <junker@anduras.de>" ); |
576 | MODULE_DESCRIPTION("PC87413 WDT driver" ); |
577 | MODULE_LICENSE("GPL" ); |
578 | |
579 | module_param_hw(io, int, ioport, 0); |
580 | MODULE_PARM_DESC(io, MODNAME " I/O port (default: " |
581 | __MODULE_STRING(IO_DEFAULT) ")." ); |
582 | |
583 | module_param(timeout, int, 0); |
584 | MODULE_PARM_DESC(timeout, |
585 | "Watchdog timeout in minutes (default=" |
586 | __MODULE_STRING(DEFAULT_TIMEOUT) ")." ); |
587 | |
588 | module_param(nowayout, bool, 0); |
589 | MODULE_PARM_DESC(nowayout, |
590 | "Watchdog cannot be stopped once started (default=" |
591 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
592 | |
593 | |