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>
41 #define DEFAULT_TIMEOUT 1 /* 1 minute */
42 #define MAX_TIMEOUT 255
45 #define MODNAME "pc87413 WDT"
46 #define DPFX MODNAME " - DEBUG: "
48 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */
49 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1)
51 #define SIOCFG2 0x22 /* Serial IO register */
52 #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */
53 #define WDTO 0x11 /* Watchdog timeout register */
54 #define WDCFG 0x12 /* Watchdog config register */
56 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
58 static int io = IO_DEFAULT;
59 static int swc_base_addr = -1;
61 static int timeout = DEFAULT_TIMEOUT; /* timeout value */
62 static unsigned long timer_enabled; /* is the timer enabled? */
64 static char expect_close; /* is the close expected? */
66 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */
68 static bool nowayout = WATCHDOG_NOWAYOUT;
70 /* -- Low level function ----------------------------------------*/
72 /* Select pins for Watchdog output */
74 static inline void pc87413_select_wdt_out(void)
76 unsigned int cr_data = 0;
78 /* Step 1: Select multiple pin,pin55,as WDT output */
80 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
82 cr_data = inb(WDT_DATA_IO_PORT);
84 cr_data |= 0x80; /* Set Bit7 to 1*/
85 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
87 outb_p(cr_data, WDT_DATA_IO_PORT);
91 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
96 /* Enable SWC functions */
98 static inline void pc87413_enable_swc(void)
100 unsigned int cr_data = 0;
102 /* Step 2: Enable SWC functions */
104 outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */
105 outb_p(SWC_LDN, WDT_DATA_IO_PORT);
107 outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */
108 cr_data = inb(WDT_DATA_IO_PORT);
109 cr_data |= 0x01; /* Set Bit0 to 1 */
110 outb_p(0x30, WDT_INDEX_IO_PORT);
111 outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */
114 pr_info(DPFX "pc87413 - Enable SWC functions\n");
118 /* Read SWC I/O base address */
120 static void pc87413_get_swc_base_addr(void)
122 unsigned char addr_l, addr_h = 0;
124 /* Step 3: Read SWC I/O Base Address */
126 outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */
127 addr_h = inb(WDT_DATA_IO_PORT);
129 outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */
131 addr_l = inb(WDT_DATA_IO_PORT);
133 swc_base_addr = (addr_h << 8) + addr_l;
136 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
137 addr_l, addr_h, swc_base_addr);
141 /* Select Bank 3 of SWC */
143 static inline void pc87413_swc_bank3(void)
145 /* Step 4: Select Bank3 of SWC */
146 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
148 pr_info(DPFX "Select Bank3 of SWC\n");
152 /* Set watchdog timeout to x minutes */
154 static inline void pc87413_programm_wdto(char pc87413_time)
156 /* Step 5: Programm WDTO, Twd. */
157 outb_p(pc87413_time, swc_base_addr + WDTO);
159 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
165 static inline void pc87413_enable_wden(void)
167 /* Step 6: Enable WDEN */
168 outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
170 pr_info(DPFX "Enable WDEN\n");
174 /* Enable SW_WD_TREN */
175 static inline void pc87413_enable_sw_wd_tren(void)
177 /* Enable SW_WD_TREN */
178 outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
180 pr_info(DPFX "Enable SW_WD_TREN\n");
184 /* Disable SW_WD_TREN */
186 static inline void pc87413_disable_sw_wd_tren(void)
188 /* Disable SW_WD_TREN */
189 outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
191 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
195 /* Enable SW_WD_TRG */
197 static inline void pc87413_enable_sw_wd_trg(void)
199 /* Enable SW_WD_TRG */
200 outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
202 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
206 /* Disable SW_WD_TRG */
208 static inline void pc87413_disable_sw_wd_trg(void)
210 /* Disable SW_WD_TRG */
211 outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
213 pr_info(DPFX "Disable SW_WD_TRG\n");
217 /* -- Higher level functions ------------------------------------*/
219 /* Enable the watchdog */
221 static void pc87413_enable(void)
226 pc87413_programm_wdto(timeout);
227 pc87413_enable_wden();
228 pc87413_enable_sw_wd_tren();
229 pc87413_enable_sw_wd_trg();
231 spin_unlock(&io_lock);
234 /* Disable the watchdog */
236 static void pc87413_disable(void)
241 pc87413_disable_sw_wd_tren();
242 pc87413_disable_sw_wd_trg();
243 pc87413_programm_wdto(0);
245 spin_unlock(&io_lock);
248 /* Refresh the watchdog */
250 static void pc87413_refresh(void)
255 pc87413_disable_sw_wd_tren();
256 pc87413_disable_sw_wd_trg();
257 pc87413_programm_wdto(timeout);
258 pc87413_enable_wden();
259 pc87413_enable_sw_wd_tren();
260 pc87413_enable_sw_wd_trg();
262 spin_unlock(&io_lock);
265 /* -- File operations -------------------------------------------*/
269 * @inode: inode of device
270 * @file: file handle to device
274 static int pc87413_open(struct inode *inode, struct file *file)
276 /* /dev/watchdog can only be opened once */
278 if (test_and_set_bit(0, &timer_enabled))
282 __module_get(THIS_MODULE);
284 /* Reload and activate timer */
287 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
289 return stream_open(inode, file);
294 * @inode: inode to board
295 * @file: file handle to board
297 * The watchdog has a configurable API. There is a religious dispute
298 * between people who want their watchdog to be able to shut down and
299 * those who want to be sure if the watchdog manager dies the machine
300 * reboots. In the former case we disable the counters, in the latter
301 * case you have to open it again very soon.
304 static int pc87413_release(struct inode *inode, struct file *file)
306 /* Shut off the timer. */
308 if (expect_close == 42) {
310 pr_info("Watchdog disabled, sleeping again...\n");
312 pr_crit("Unexpected close, not stopping watchdog!\n");
315 clear_bit(0, &timer_enabled);
323 * return, if the watchdog is enabled (timeout is set...)
327 static int pc87413_status(void)
329 return 0; /* currently not supported */
334 * @file: file handle to the watchdog
335 * @data: data buffer to write
336 * @len: length in bytes
337 * @ppos: pointer to the position to write. No seeks allowed
339 * A write to a watchdog device is defined as a keepalive signal. Any
340 * write of data will do, as we we don't define content meaning.
343 static ssize_t pc87413_write(struct file *file, const char __user *data,
344 size_t len, loff_t *ppos)
346 /* See if we got the magic character 'V' and reload the timer */
351 /* reset expect flag */
354 /* scan to see whether or not we got the
356 for (i = 0; i != len; i++) {
358 if (get_user(c, data + i))
365 /* someone wrote to us, we should reload the timer */
373 * @file: file handle to the device
374 * @cmd: watchdog command
375 * @arg: argument pointer
377 * The watchdog API defines a common set of functions for all watchdogs
378 * according to their available features. We only actually usefully support
379 * querying capabilities and current status.
382 static long pc87413_ioctl(struct file *file, unsigned int cmd,
388 struct watchdog_info __user *ident;
392 static const struct watchdog_info ident = {
393 .options = WDIOF_KEEPALIVEPING |
396 .firmware_version = 1,
397 .identity = "PC87413(HF/F) watchdog",
400 uarg.i = (int __user *)arg;
403 case WDIOC_GETSUPPORT:
404 return copy_to_user(uarg.ident, &ident,
405 sizeof(ident)) ? -EFAULT : 0;
406 case WDIOC_GETSTATUS:
407 return put_user(pc87413_status(), uarg.i);
408 case WDIOC_GETBOOTSTATUS:
409 return put_user(0, uarg.i);
410 case WDIOC_SETOPTIONS:
412 int options, retval = -EINVAL;
413 if (get_user(options, uarg.i))
415 if (options & WDIOS_DISABLECARD) {
419 if (options & WDIOS_ENABLECARD) {
425 case WDIOC_KEEPALIVE:
428 pr_info(DPFX "keepalive\n");
431 case WDIOC_SETTIMEOUT:
432 if (get_user(new_timeout, uarg.i))
434 /* the API states this is given in secs */
436 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
438 timeout = new_timeout;
440 /* fall through - and return the new timeout... */
441 case WDIOC_GETTIMEOUT:
442 new_timeout = timeout * 60;
443 return put_user(new_timeout, uarg.i);
449 /* -- Notifier funtions -----------------------------------------*/
453 * @this: our notifier block
454 * @code: the event being reported
457 * Our notifier is called on system shutdowns. We want to turn the card
458 * off at reboot otherwise the machine will reboot again during memory
459 * test or worse yet during the following fsck. This would suck, in fact
460 * trust me - if it happens it does suck.
463 static int pc87413_notify_sys(struct notifier_block *this,
467 if (code == SYS_DOWN || code == SYS_HALT)
468 /* Turn the card off */
473 /* -- Module's structures ---------------------------------------*/
475 static const struct file_operations pc87413_fops = {
476 .owner = THIS_MODULE,
478 .write = pc87413_write,
479 .unlocked_ioctl = pc87413_ioctl,
480 .open = pc87413_open,
481 .release = pc87413_release,
484 static struct notifier_block pc87413_notifier = {
485 .notifier_call = pc87413_notify_sys,
488 static struct miscdevice pc87413_miscdev = {
489 .minor = WATCHDOG_MINOR,
491 .fops = &pc87413_fops,
494 /* -- Module init functions -------------------------------------*/
497 * pc87413_init: module's "constructor"
499 * Set up the WDT watchdog board. All we have to do is grab the
500 * resources we require and bitch if anyone beat us to them.
501 * The open() function will actually kick the board off.
504 static int __init pc87413_init(void)
508 pr_info("Version " VERSION " at io 0x%X\n",
511 if (!request_muxed_region(io, 2, MODNAME))
514 ret = register_reboot_notifier(&pc87413_notifier);
516 pr_err("cannot register reboot notifier (err=%d)\n", ret);
518 ret = misc_register(&pc87413_miscdev);
520 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
521 WATCHDOG_MINOR, ret);
524 pr_info("initialized. timeout=%d min\n", timeout);
526 pc87413_select_wdt_out();
527 pc87413_enable_swc();
528 pc87413_get_swc_base_addr();
530 if (!request_region(swc_base_addr, 0x20, MODNAME)) {
531 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
538 release_region(io, 2);
542 misc_deregister(&pc87413_miscdev);
544 unregister_reboot_notifier(&pc87413_notifier);
545 release_region(io, 2);
550 * pc87413_exit: module's "destructor"
552 * Unload the watchdog. You cannot do this with any file handles open.
553 * If your watchdog is set to continue ticking on close and you unload
554 * it, well it keeps ticking. We won't get the interrupt but the board
555 * will not touch PC memory so all is fine. You just have to load a new
556 * module in 60 seconds or reboot.
559 static void __exit pc87413_exit(void)
561 /* Stop the timer before we leave */
564 pr_info("Watchdog disabled\n");
567 misc_deregister(&pc87413_miscdev);
568 unregister_reboot_notifier(&pc87413_notifier);
569 release_region(swc_base_addr, 0x20);
571 pr_info("watchdog component driver removed\n");
574 module_init(pc87413_init);
575 module_exit(pc87413_exit);
577 MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
578 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
579 MODULE_DESCRIPTION("PC87413 WDT driver");
580 MODULE_LICENSE("GPL");
582 module_param_hw(io, int, ioport, 0);
583 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
584 __MODULE_STRING(IO_DEFAULT) ").");
586 module_param(timeout, int, 0);
587 MODULE_PARM_DESC(timeout,
588 "Watchdog timeout in minutes (default="
589 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
591 module_param(nowayout, bool, 0);
592 MODULE_PARM_DESC(nowayout,
593 "Watchdog cannot be stopped once started (default="
594 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");