2 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
4 * This code is based on wdt.c with original copyright.
6 * (C) Copyright 2006 Sven Anders, <anders@anduras.de>
7 * and Marcus Junker, <junker@anduras.de>
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
14 * Neither Sven Anders, Marcus Junker nor ANDURAS AG
15 * admit liability nor provide warranty for any of this software.
16 * This material is provided "AS-IS" and at no charge.
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/ioport.h>
28 #include <linux/delay.h>
29 #include <linux/notifier.h>
31 #include <linux/reboot.h>
32 #include <linux/init.h>
33 #include <linux/spinlock.h>
34 #include <linux/moduleparam.h>
36 #include <linux/uaccess.h>
38 #include <asm/system.h>
42 #define DEFAULT_TIMEOUT 1 /* 1 minute */
43 #define MAX_TIMEOUT 255
46 #define MODNAME "pc87413 WDT"
47 #define DPFX MODNAME " - DEBUG: "
49 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */
50 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1)
52 #define SIOCFG2 0x22 /* Serial IO register */
53 #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */
54 #define WDTO 0x11 /* Watchdog timeout register */
55 #define WDCFG 0x12 /* Watchdog config register */
57 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
59 static int io
= IO_DEFAULT
;
60 static int swc_base_addr
= -1;
62 static int timeout
= DEFAULT_TIMEOUT
; /* timeout value */
63 static unsigned long timer_enabled
; /* is the timer enabled? */
65 static char expect_close
; /* is the close expected? */
67 static DEFINE_SPINLOCK(io_lock
); /* to guard us from io races */
69 static int nowayout
= WATCHDOG_NOWAYOUT
;
71 /* -- Low level function ----------------------------------------*/
73 /* Select pins for Watchdog output */
75 static inline void pc87413_select_wdt_out(void)
77 unsigned int cr_data
= 0;
79 /* Step 1: Select multiple pin,pin55,as WDT output */
81 outb_p(SIOCFG2
, WDT_INDEX_IO_PORT
);
83 cr_data
= inb(WDT_DATA_IO_PORT
);
85 cr_data
|= 0x80; /* Set Bit7 to 1*/
86 outb_p(SIOCFG2
, WDT_INDEX_IO_PORT
);
88 outb_p(cr_data
, WDT_DATA_IO_PORT
);
92 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
97 /* Enable SWC functions */
99 static inline void pc87413_enable_swc(void)
101 unsigned int cr_data
= 0;
103 /* Step 2: Enable SWC functions */
105 outb_p(0x07, WDT_INDEX_IO_PORT
); /* Point SWC_LDN (LDN=4) */
106 outb_p(SWC_LDN
, WDT_DATA_IO_PORT
);
108 outb_p(0x30, WDT_INDEX_IO_PORT
); /* Read Index 0x30 First */
109 cr_data
= inb(WDT_DATA_IO_PORT
);
110 cr_data
|= 0x01; /* Set Bit0 to 1 */
111 outb_p(0x30, WDT_INDEX_IO_PORT
);
112 outb_p(cr_data
, WDT_DATA_IO_PORT
); /* Index0x30_bit0P1 */
115 pr_info(DPFX
"pc87413 - Enable SWC functions\n");
119 /* Read SWC I/O base address */
121 static void pc87413_get_swc_base_addr(void)
123 unsigned char addr_l
, addr_h
= 0;
125 /* Step 3: Read SWC I/O Base Address */
127 outb_p(0x60, WDT_INDEX_IO_PORT
); /* Read Index 0x60 */
128 addr_h
= inb(WDT_DATA_IO_PORT
);
130 outb_p(0x61, WDT_INDEX_IO_PORT
); /* Read Index 0x61 */
132 addr_l
= inb(WDT_DATA_IO_PORT
);
134 swc_base_addr
= (addr_h
<< 8) + addr_l
;
137 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
138 addr_l
, addr_h
, swc_base_addr
);
142 /* Select Bank 3 of SWC */
144 static inline void pc87413_swc_bank3(void)
146 /* Step 4: Select Bank3 of SWC */
147 outb_p(inb(swc_base_addr
+ 0x0f) | 0x03, swc_base_addr
+ 0x0f);
149 pr_info(DPFX
"Select Bank3 of SWC\n");
153 /* Set watchdog timeout to x minutes */
155 static inline void pc87413_programm_wdto(char pc87413_time
)
157 /* Step 5: Programm WDTO, Twd. */
158 outb_p(pc87413_time
, swc_base_addr
+ WDTO
);
160 pr_info(DPFX
"Set WDTO to %d minutes\n", pc87413_time
);
166 static inline void pc87413_enable_wden(void)
168 /* Step 6: Enable WDEN */
169 outb_p(inb(swc_base_addr
+ WDCTL
) | 0x01, swc_base_addr
+ WDCTL
);
171 pr_info(DPFX
"Enable WDEN\n");
175 /* Enable SW_WD_TREN */
176 static inline void pc87413_enable_sw_wd_tren(void)
178 /* Enable SW_WD_TREN */
179 outb_p(inb(swc_base_addr
+ WDCFG
) | 0x80, swc_base_addr
+ WDCFG
);
181 pr_info(DPFX
"Enable SW_WD_TREN\n");
185 /* Disable SW_WD_TREN */
187 static inline void pc87413_disable_sw_wd_tren(void)
189 /* Disable SW_WD_TREN */
190 outb_p(inb(swc_base_addr
+ WDCFG
) & 0x7f, swc_base_addr
+ WDCFG
);
192 pr_info(DPFX
"pc87413 - Disable SW_WD_TREN\n");
196 /* Enable SW_WD_TRG */
198 static inline void pc87413_enable_sw_wd_trg(void)
200 /* Enable SW_WD_TRG */
201 outb_p(inb(swc_base_addr
+ WDCTL
) | 0x80, swc_base_addr
+ WDCTL
);
203 pr_info(DPFX
"pc87413 - Enable SW_WD_TRG\n");
207 /* Disable SW_WD_TRG */
209 static inline void pc87413_disable_sw_wd_trg(void)
211 /* Disable SW_WD_TRG */
212 outb_p(inb(swc_base_addr
+ WDCTL
) & 0x7f, swc_base_addr
+ WDCTL
);
214 pr_info(DPFX
"Disable SW_WD_TRG\n");
218 /* -- Higher level functions ------------------------------------*/
220 /* Enable the watchdog */
222 static void pc87413_enable(void)
227 pc87413_programm_wdto(timeout
);
228 pc87413_enable_wden();
229 pc87413_enable_sw_wd_tren();
230 pc87413_enable_sw_wd_trg();
232 spin_unlock(&io_lock
);
235 /* Disable the watchdog */
237 static void pc87413_disable(void)
242 pc87413_disable_sw_wd_tren();
243 pc87413_disable_sw_wd_trg();
244 pc87413_programm_wdto(0);
246 spin_unlock(&io_lock
);
249 /* Refresh the watchdog */
251 static void pc87413_refresh(void)
256 pc87413_disable_sw_wd_tren();
257 pc87413_disable_sw_wd_trg();
258 pc87413_programm_wdto(timeout
);
259 pc87413_enable_wden();
260 pc87413_enable_sw_wd_tren();
261 pc87413_enable_sw_wd_trg();
263 spin_unlock(&io_lock
);
266 /* -- File operations -------------------------------------------*/
270 * @inode: inode of device
271 * @file: file handle to device
275 static int pc87413_open(struct inode
*inode
, struct file
*file
)
277 /* /dev/watchdog can only be opened once */
279 if (test_and_set_bit(0, &timer_enabled
))
283 __module_get(THIS_MODULE
);
285 /* Reload and activate timer */
288 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout
);
290 return nonseekable_open(inode
, file
);
295 * @inode: inode to board
296 * @file: file handle to board
298 * The watchdog has a configurable API. There is a religious dispute
299 * between people who want their watchdog to be able to shut down and
300 * those who want to be sure if the watchdog manager dies the machine
301 * reboots. In the former case we disable the counters, in the latter
302 * case you have to open it again very soon.
305 static int pc87413_release(struct inode
*inode
, struct file
*file
)
307 /* Shut off the timer. */
309 if (expect_close
== 42) {
311 pr_info("Watchdog disabled, sleeping again...\n");
313 pr_crit("Unexpected close, not stopping watchdog!\n");
316 clear_bit(0, &timer_enabled
);
324 * return, if the watchdog is enabled (timeout is set...)
328 static int pc87413_status(void)
330 return 0; /* currently not supported */
335 * @file: file handle to the watchdog
336 * @data: data buffer to write
337 * @len: length in bytes
338 * @ppos: pointer to the position to write. No seeks allowed
340 * A write to a watchdog device is defined as a keepalive signal. Any
341 * write of data will do, as we we don't define content meaning.
344 static ssize_t
pc87413_write(struct file
*file
, const char __user
*data
,
345 size_t len
, loff_t
*ppos
)
347 /* See if we got the magic character 'V' and reload the timer */
352 /* reset expect flag */
355 /* scan to see whether or not we got the
357 for (i
= 0; i
!= len
; i
++) {
359 if (get_user(c
, data
+ i
))
366 /* someone wrote to us, we should reload the timer */
374 * @file: file handle to the device
375 * @cmd: watchdog command
376 * @arg: argument pointer
378 * The watchdog API defines a common set of functions for all watchdogs
379 * according to their available features. We only actually usefully support
380 * querying capabilities and current status.
383 static long pc87413_ioctl(struct file
*file
, unsigned int cmd
,
389 struct watchdog_info __user
*ident
;
393 static const struct watchdog_info ident
= {
394 .options
= WDIOF_KEEPALIVEPING
|
397 .firmware_version
= 1,
398 .identity
= "PC87413(HF/F) watchdog",
401 uarg
.i
= (int __user
*)arg
;
404 case WDIOC_GETSUPPORT
:
405 return copy_to_user(uarg
.ident
, &ident
,
406 sizeof(ident
)) ? -EFAULT
: 0;
407 case WDIOC_GETSTATUS
:
408 return put_user(pc87413_status(), uarg
.i
);
409 case WDIOC_GETBOOTSTATUS
:
410 return put_user(0, uarg
.i
);
411 case WDIOC_SETOPTIONS
:
413 int options
, retval
= -EINVAL
;
414 if (get_user(options
, uarg
.i
))
416 if (options
& WDIOS_DISABLECARD
) {
420 if (options
& WDIOS_ENABLECARD
) {
426 case WDIOC_KEEPALIVE
:
429 pr_info(DPFX
"keepalive\n");
432 case WDIOC_SETTIMEOUT
:
433 if (get_user(new_timeout
, uarg
.i
))
435 /* the API states this is given in secs */
437 if (new_timeout
< 0 || new_timeout
> MAX_TIMEOUT
)
439 timeout
= new_timeout
;
441 /* fall through and return the new timeout... */
442 case WDIOC_GETTIMEOUT
:
443 new_timeout
= timeout
* 60;
444 return put_user(new_timeout
, uarg
.i
);
450 /* -- Notifier funtions -----------------------------------------*/
454 * @this: our notifier block
455 * @code: the event being reported
458 * Our notifier is called on system shutdowns. We want to turn the card
459 * off at reboot otherwise the machine will reboot again during memory
460 * test or worse yet during the following fsck. This would suck, in fact
461 * trust me - if it happens it does suck.
464 static int pc87413_notify_sys(struct notifier_block
*this,
468 if (code
== SYS_DOWN
|| code
== SYS_HALT
)
469 /* Turn the card off */
474 /* -- Module's structures ---------------------------------------*/
476 static const struct file_operations pc87413_fops
= {
477 .owner
= THIS_MODULE
,
479 .write
= pc87413_write
,
480 .unlocked_ioctl
= pc87413_ioctl
,
481 .open
= pc87413_open
,
482 .release
= pc87413_release
,
485 static struct notifier_block pc87413_notifier
= {
486 .notifier_call
= pc87413_notify_sys
,
489 static struct miscdevice pc87413_miscdev
= {
490 .minor
= WATCHDOG_MINOR
,
492 .fops
= &pc87413_fops
,
495 /* -- Module init functions -------------------------------------*/
498 * pc87413_init: module's "constructor"
500 * Set up the WDT watchdog board. All we have to do is grab the
501 * resources we require and bitch if anyone beat us to them.
502 * The open() function will actually kick the board off.
505 static int __init
pc87413_init(void)
509 pr_info("Version " VERSION
" at io 0x%X\n",
512 if (!request_muxed_region(io
, 2, MODNAME
))
515 ret
= register_reboot_notifier(&pc87413_notifier
);
517 pr_err("cannot register reboot notifier (err=%d)\n", ret
);
520 ret
= misc_register(&pc87413_miscdev
);
522 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
523 WATCHDOG_MINOR
, ret
);
526 pr_info("initialized. timeout=%d min\n", timeout
);
528 pc87413_select_wdt_out();
529 pc87413_enable_swc();
530 pc87413_get_swc_base_addr();
532 if (!request_region(swc_base_addr
, 0x20, MODNAME
)) {
533 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr
);
540 release_region(io
, 2);
544 misc_deregister(&pc87413_miscdev
);
546 unregister_reboot_notifier(&pc87413_notifier
);
547 release_region(io
, 2);
552 * pc87413_exit: module's "destructor"
554 * Unload the watchdog. You cannot do this with any file handles open.
555 * If your watchdog is set to continue ticking on close and you unload
556 * it, well it keeps ticking. We won't get the interrupt but the board
557 * will not touch PC memory so all is fine. You just have to load a new
558 * module in 60 seconds or reboot.
561 static void __exit
pc87413_exit(void)
563 /* Stop the timer before we leave */
566 pr_info("Watchdog disabled\n");
569 misc_deregister(&pc87413_miscdev
);
570 unregister_reboot_notifier(&pc87413_notifier
);
571 release_region(swc_base_addr
, 0x20);
573 pr_info("watchdog component driver removed\n");
576 module_init(pc87413_init
);
577 module_exit(pc87413_exit
);
579 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
580 "Marcus Junker <junker@anduras.de>,");
581 MODULE_DESCRIPTION("PC87413 WDT driver");
582 MODULE_LICENSE("GPL");
584 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);
586 module_param(io
, int, 0);
587 MODULE_PARM_DESC(io
, MODNAME
" I/O port (default: "
588 __MODULE_STRING(IO_DEFAULT
) ").");
590 module_param(timeout
, int, 0);
591 MODULE_PARM_DESC(timeout
,
592 "Watchdog timeout in minutes (default="
593 __MODULE_STRING(DEFAULT_TIMEOUT
) ").");
595 module_param(nowayout
, int, 0);
596 MODULE_PARM_DESC(nowayout
,
597 "Watchdog cannot be stopped once started (default="
598 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");