1 // SPDX-License-Identifier: GPL-2.0+
3 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
5 * This code is based on wdt.c with original copyright.
7 * (C) Copyright 2006 Sven Anders, <anders@anduras.de>
8 * and Marcus Junker, <junker@anduras.de>
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.
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
27 #include <linux/reboot.h>
28 #include <linux/init.h>
29 #include <linux/spinlock.h>
30 #include <linux/moduleparam.h>
32 #include <linux/uaccess.h>
37 #define DEFAULT_TIMEOUT 1 /* 1 minute */
38 #define MAX_TIMEOUT 255
41 #define MODNAME "pc87413 WDT"
42 #define DPFX MODNAME " - DEBUG: "
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)
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 */
52 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
54 static int io = IO_DEFAULT;
55 static int swc_base_addr = -1;
57 static int timeout = DEFAULT_TIMEOUT; /* timeout value */
58 static unsigned long timer_enabled; /* is the timer enabled? */
60 static char expect_close; /* is the close expected? */
62 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */
64 static bool nowayout = WATCHDOG_NOWAYOUT;
66 /* -- Low level function ----------------------------------------*/
68 /* Select pins for Watchdog output */
70 static inline void pc87413_select_wdt_out(void)
72 unsigned int cr_data = 0;
74 /* Step 1: Select multiple pin,pin55,as WDT output */
76 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
78 cr_data = inb(WDT_DATA_IO_PORT);
80 cr_data |= 0x80; /* Set Bit7 to 1*/
81 outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
83 outb_p(cr_data, WDT_DATA_IO_PORT);
87 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
92 /* Enable SWC functions */
94 static inline void pc87413_enable_swc(void)
96 unsigned int cr_data = 0;
98 /* Step 2: Enable SWC functions */
100 outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */
101 outb_p(SWC_LDN, WDT_DATA_IO_PORT);
103 outb_p(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(0x30, WDT_INDEX_IO_PORT);
107 outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */
110 pr_info(DPFX "pc87413 - Enable SWC functions\n");
114 /* Read SWC I/O base address */
116 static void pc87413_get_swc_base_addr(void)
118 unsigned char addr_l, addr_h = 0;
120 /* Step 3: Read SWC I/O Base Address */
122 outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */
123 addr_h = inb(WDT_DATA_IO_PORT);
125 outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */
127 addr_l = inb(WDT_DATA_IO_PORT);
129 swc_base_addr = (addr_h << 8) + addr_l;
132 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
133 addr_l, addr_h, swc_base_addr);
137 /* Select Bank 3 of SWC */
139 static inline void pc87413_swc_bank3(void)
141 /* Step 4: Select Bank3 of SWC */
142 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
144 pr_info(DPFX "Select Bank3 of SWC\n");
148 /* Set watchdog timeout to x minutes */
150 static inline void pc87413_programm_wdto(char pc87413_time)
152 /* Step 5: Programm WDTO, Twd. */
153 outb_p(pc87413_time, swc_base_addr + WDTO);
155 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
161 static inline void pc87413_enable_wden(void)
163 /* Step 6: Enable WDEN */
164 outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
166 pr_info(DPFX "Enable WDEN\n");
170 /* Enable SW_WD_TREN */
171 static inline void pc87413_enable_sw_wd_tren(void)
173 /* Enable SW_WD_TREN */
174 outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
176 pr_info(DPFX "Enable SW_WD_TREN\n");
180 /* Disable SW_WD_TREN */
182 static inline void pc87413_disable_sw_wd_tren(void)
184 /* Disable SW_WD_TREN */
185 outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
187 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
191 /* Enable SW_WD_TRG */
193 static inline void pc87413_enable_sw_wd_trg(void)
195 /* Enable SW_WD_TRG */
196 outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
198 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
202 /* Disable SW_WD_TRG */
204 static inline void pc87413_disable_sw_wd_trg(void)
206 /* Disable SW_WD_TRG */
207 outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
209 pr_info(DPFX "Disable SW_WD_TRG\n");
213 /* -- Higher level functions ------------------------------------*/
215 /* Enable the watchdog */
217 static void pc87413_enable(void)
222 pc87413_programm_wdto(timeout);
223 pc87413_enable_wden();
224 pc87413_enable_sw_wd_tren();
225 pc87413_enable_sw_wd_trg();
227 spin_unlock(&io_lock);
230 /* Disable the watchdog */
232 static void pc87413_disable(void)
237 pc87413_disable_sw_wd_tren();
238 pc87413_disable_sw_wd_trg();
239 pc87413_programm_wdto(0);
241 spin_unlock(&io_lock);
244 /* Refresh the watchdog */
246 static void pc87413_refresh(void)
251 pc87413_disable_sw_wd_tren();
252 pc87413_disable_sw_wd_trg();
253 pc87413_programm_wdto(timeout);
254 pc87413_enable_wden();
255 pc87413_enable_sw_wd_tren();
256 pc87413_enable_sw_wd_trg();
258 spin_unlock(&io_lock);
261 /* -- File operations -------------------------------------------*/
265 * @inode: inode of device
266 * @file: file handle to device
270 static int pc87413_open(struct inode *inode, struct file *file)
272 /* /dev/watchdog can only be opened once */
274 if (test_and_set_bit(0, &timer_enabled))
278 __module_get(THIS_MODULE);
280 /* Reload and activate timer */
283 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
285 return stream_open(inode, file);
290 * @inode: inode to board
291 * @file: file handle to board
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.
300 static int pc87413_release(struct inode *inode, struct file *file)
302 /* Shut off the timer. */
304 if (expect_close == 42) {
306 pr_info("Watchdog disabled, sleeping again...\n");
308 pr_crit("Unexpected close, not stopping watchdog!\n");
311 clear_bit(0, &timer_enabled);
319 * return, if the watchdog is enabled (timeout is set...)
323 static int pc87413_status(void)
325 return 0; /* currently not supported */
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
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.
339 static ssize_t pc87413_write(struct file *file, const char __user *data,
340 size_t len, loff_t *ppos)
342 /* See if we got the magic character 'V' and reload the timer */
347 /* reset expect flag */
350 /* scan to see whether or not we got the
352 for (i = 0; i != len; i++) {
354 if (get_user(c, data + i))
361 /* someone wrote to us, we should reload the timer */
369 * @file: file handle to the device
370 * @cmd: watchdog command
371 * @arg: argument pointer
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.
378 static long pc87413_ioctl(struct file *file, unsigned int cmd,
384 struct watchdog_info __user *ident;
388 static const struct watchdog_info ident = {
389 .options = WDIOF_KEEPALIVEPING |
392 .firmware_version = 1,
393 .identity = "PC87413(HF/F) watchdog",
396 uarg.i = (int __user *)arg;
399 case WDIOC_GETSUPPORT:
400 return copy_to_user(uarg.ident, &ident,
401 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:
408 int options, retval = -EINVAL;
409 if (get_user(options, uarg.i))
411 if (options & WDIOS_DISABLECARD) {
415 if (options & WDIOS_ENABLECARD) {
421 case WDIOC_KEEPALIVE:
424 pr_info(DPFX "keepalive\n");
427 case WDIOC_SETTIMEOUT:
428 if (get_user(new_timeout, uarg.i))
430 /* the API states this is given in secs */
432 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
434 timeout = new_timeout;
436 fallthrough; /* and return the new timeout */
437 case WDIOC_GETTIMEOUT:
438 new_timeout = timeout * 60;
439 return put_user(new_timeout, uarg.i);
445 /* -- Notifier funtions -----------------------------------------*/
449 * @this: our notifier block
450 * @code: the event being reported
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.
459 static int pc87413_notify_sys(struct notifier_block *this,
463 if (code == SYS_DOWN || code == SYS_HALT)
464 /* Turn the card off */
469 /* -- Module's structures ---------------------------------------*/
471 static const struct file_operations pc87413_fops = {
472 .owner = THIS_MODULE,
474 .write = pc87413_write,
475 .unlocked_ioctl = pc87413_ioctl,
476 .compat_ioctl = compat_ptr_ioctl,
477 .open = pc87413_open,
478 .release = pc87413_release,
481 static struct notifier_block pc87413_notifier = {
482 .notifier_call = pc87413_notify_sys,
485 static struct miscdevice pc87413_miscdev = {
486 .minor = WATCHDOG_MINOR,
488 .fops = &pc87413_fops,
491 /* -- Module init functions -------------------------------------*/
494 * pc87413_init: module's "constructor"
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.
501 static int __init pc87413_init(void)
505 pr_info("Version " VERSION " at io 0x%X\n",
508 if (!request_muxed_region(io, 2, MODNAME))
511 ret = register_reboot_notifier(&pc87413_notifier);
513 pr_err("cannot register reboot notifier (err=%d)\n", ret);
515 ret = misc_register(&pc87413_miscdev);
517 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
518 WATCHDOG_MINOR, ret);
521 pr_info("initialized. timeout=%d min\n", timeout);
523 pc87413_select_wdt_out();
524 pc87413_enable_swc();
525 pc87413_get_swc_base_addr();
527 if (!request_region(swc_base_addr, 0x20, MODNAME)) {
528 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
535 release_region(io, 2);
539 misc_deregister(&pc87413_miscdev);
541 unregister_reboot_notifier(&pc87413_notifier);
542 release_region(io, 2);
547 * pc87413_exit: module's "destructor"
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.
556 static void __exit pc87413_exit(void)
558 /* Stop the timer before we leave */
561 pr_info("Watchdog disabled\n");
564 misc_deregister(&pc87413_miscdev);
565 unregister_reboot_notifier(&pc87413_notifier);
566 release_region(swc_base_addr, 0x20);
568 pr_info("watchdog component driver removed\n");
571 module_init(pc87413_init);
572 module_exit(pc87413_exit);
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");
579 module_param_hw(io, int, ioport, 0);
580 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
581 __MODULE_STRING(IO_DEFAULT) ").");
583 module_param(timeout, int, 0);
584 MODULE_PARM_DESC(timeout,
585 "Watchdog timeout in minutes (default="
586 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
588 module_param(nowayout, bool, 0);
589 MODULE_PARM_DESC(nowayout,
590 "Watchdog cannot be stopped once started (default="
591 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");