1/* 2 * W83877F Computer Watchdog Timer driver 3 * 4 * Based on acquirewdt.c by Alan Cox, 5 * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * The authors do NOT admit liability nor provide warranty for 13 * any of this software. This material is provided "AS-IS" in 14 * the hope that it may be useful for others. 15 * 16 * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net> 17 * 18 * 4/19 - 2001 [Initial revision] 19 * 9/27 - 2001 Added spinlocking 20 * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments 21 * Eliminate fop_read 22 * Eliminate extra spin_unlock 23 * Added KERN_* tags to printks 24 * add CONFIG_WATCHDOG_NOWAYOUT support 25 * fix possible wdt_is_open race 26 * changed watchdog_info to correctly reflect what 27 * the driver offers 28 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, 29 * WDIOC_SETTIMEOUT, 30 * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls 31 * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces 32 * added extra printk's for startup problems 33 * use module_param 34 * made timeout (the emulated heartbeat) a 35 * module_param 36 * made the keepalive ping an internal subroutine 37 * 38 * This WDT driver is different from most other Linux WDT 39 * drivers in that the driver will ping the watchdog by itself, 40 * because this particular WDT has a very short timeout (1.6 41 * seconds) and it would be insane to count on any userspace 42 * daemon always getting scheduled within that time frame. 43 */ 44 45#include <linux/module.h> 46#include <linux/moduleparam.h> 47#include <linux/types.h> 48#include <linux/timer.h> 49#include <linux/jiffies.h> 50#include <linux/miscdevice.h> 51#include <linux/watchdog.h> 52#include <linux/fs.h> 53#include <linux/ioport.h> 54#include <linux/notifier.h> 55#include <linux/reboot.h> 56#include <linux/init.h> 57#include <linux/io.h> 58#include <linux/uaccess.h> 59#include <asm/system.h> 60 61#define OUR_NAME "w83877f_wdt" 62#define PFX OUR_NAME ": " 63 64#define ENABLE_W83877F_PORT 0x3F0 65#define ENABLE_W83877F 0x87 66#define DISABLE_W83877F 0xAA 67#define WDT_PING 0x443 68#define WDT_REGISTER 0x14 69#define WDT_ENABLE 0x9C 70#define WDT_DISABLE 0x8C 71 72/* 73 * The W83877F seems to be fixed at 1.6s timeout (at least on the 74 * EMACS PC-104 board I'm using). If we reset the watchdog every 75 * ~250ms we should be safe. */ 76 77#define WDT_INTERVAL (HZ/4+1) 78 79/* 80 * We must not require too good response from the userspace daemon. 81 * Here we require the userspace daemon to send us a heartbeat 82 * char to /dev/watchdog every 30 seconds. 83 */ 84 85#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ 86/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ 87static int timeout = WATCHDOG_TIMEOUT; 88module_param(timeout, int, 0); 89MODULE_PARM_DESC(timeout, 90 "Watchdog timeout in seconds. (1<=timeout<=3600, default=" 91 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 92 93 94static int nowayout = WATCHDOG_NOWAYOUT; 95module_param(nowayout, int, 0); 96MODULE_PARM_DESC(nowayout, 97 "Watchdog cannot be stopped once started (default=" 98 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 99 100static void wdt_timer_ping(unsigned long); 101static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); 102static unsigned long next_heartbeat; 103static unsigned long wdt_is_open; 104static char wdt_expect_close; 105static DEFINE_SPINLOCK(wdt_spinlock); 106 107/* 108 * Whack the dog 109 */ 110 111static void wdt_timer_ping(unsigned long data) 112{ 113 /* If we got a heartbeat pulse within the WDT_US_INTERVAL 114 * we agree to ping the WDT 115 */ 116 if (time_before(jiffies, next_heartbeat)) { 117 /* Ping the WDT */ 118 spin_lock(&wdt_spinlock); 119 120 /* Ping the WDT by reading from WDT_PING */ 121 inb_p(WDT_PING); 122 123 /* Re-set the timer interval */ 124 mod_timer(&timer, jiffies + WDT_INTERVAL); 125 126 spin_unlock(&wdt_spinlock); 127 128 } else 129 printk(KERN_WARNING PFX 130 "Heartbeat lost! Will not ping the watchdog\n"); 131} 132 133/* 134 * Utility routines 135 */ 136 137static void wdt_change(int writeval) 138{ 139 unsigned long flags; 140 spin_lock_irqsave(&wdt_spinlock, flags); 141 142 /* buy some time */ 143 inb_p(WDT_PING); 144 145 /* make W83877F available */ 146 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); 147 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); 148 149 /* enable watchdog */ 150 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); 151 outb_p(writeval, ENABLE_W83877F_PORT+1); 152 153 /* lock the W8387FF away */ 154 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); 155 156 spin_unlock_irqrestore(&wdt_spinlock, flags); 157} 158 159static void wdt_startup(void) 160{ 161 next_heartbeat = jiffies + (timeout * HZ); 162 163 /* Start the timer */ 164 mod_timer(&timer, jiffies + WDT_INTERVAL); 165 166 wdt_change(WDT_ENABLE); 167 168 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); 169} 170 171static void wdt_turnoff(void) 172{ 173 /* Stop the timer */ 174 del_timer(&timer); 175 176 wdt_change(WDT_DISABLE); 177 178 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); 179} 180 181static void wdt_keepalive(void) 182{ 183 /* user land ping */ 184 next_heartbeat = jiffies + (timeout * HZ); 185} 186 187/* 188 * /dev/watchdog handling 189 */ 190 191static ssize_t fop_write(struct file *file, const char __user *buf, 192 size_t count, loff_t *ppos) 193{ 194 /* See if we got the magic character 'V' and reload the timer */ 195 if (count) { 196 if (!nowayout) { 197 size_t ofs; 198 199 /* note: just in case someone wrote the magic 200 character five months ago... */ 201 wdt_expect_close = 0; 202 203 /* scan to see whether or not we got the 204 magic character */ 205 for (ofs = 0; ofs != count; ofs++) { 206 char c; 207 if (get_user(c, buf + ofs)) 208 return -EFAULT; 209 if (c == 'V') 210 wdt_expect_close = 42; 211 } 212 } 213 214 /* someone wrote to us, we should restart timer */ 215 wdt_keepalive(); 216 } 217 return count; 218} 219 220static int fop_open(struct inode *inode, struct file *file) 221{ 222 /* Just in case we're already talking to someone... */ 223 if (test_and_set_bit(0, &wdt_is_open)) 224 return -EBUSY; 225 226 /* Good, fire up the show */ 227 wdt_startup(); 228 return nonseekable_open(inode, file); 229} 230 231static int fop_close(struct inode *inode, struct file *file) 232{ 233 if (wdt_expect_close == 42) 234 wdt_turnoff(); 235 else { 236 del_timer(&timer); 237 printk(KERN_CRIT PFX 238 "device file closed unexpectedly. Will not stop the WDT!\n"); 239 } 240 clear_bit(0, &wdt_is_open); 241 wdt_expect_close = 0; 242 return 0; 243} 244 245static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 246{ 247 void __user *argp = (void __user *)arg; 248 int __user *p = argp; 249 static const struct watchdog_info ident = { 250 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT 251 | WDIOF_MAGICCLOSE, 252 .firmware_version = 1, 253 .identity = "W83877F", 254 }; 255 256 switch (cmd) { 257 case WDIOC_GETSUPPORT: 258 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 259 case WDIOC_GETSTATUS: 260 case WDIOC_GETBOOTSTATUS: 261 return put_user(0, p); 262 case WDIOC_SETOPTIONS: 263 { 264 int new_options, retval = -EINVAL; 265 266 if (get_user(new_options, p)) 267 return -EFAULT; 268 269 if (new_options & WDIOS_DISABLECARD) { 270 wdt_turnoff(); 271 retval = 0; 272 } 273 274 if (new_options & WDIOS_ENABLECARD) { 275 wdt_startup(); 276 retval = 0; 277 } 278 279 return retval; 280 } 281 case WDIOC_KEEPALIVE: 282 wdt_keepalive(); 283 return 0; 284 case WDIOC_SETTIMEOUT: 285 { 286 int new_timeout; 287 288 if (get_user(new_timeout, p)) 289 return -EFAULT; 290 291 /* arbitrary upper limit */ 292 if (new_timeout < 1 || new_timeout > 3600) 293 return -EINVAL; 294 295 timeout = new_timeout; 296 wdt_keepalive(); 297 /* Fall through */ 298 } 299 case WDIOC_GETTIMEOUT: 300 return put_user(timeout, p); 301 default: 302 return -ENOTTY; 303 } 304} 305 306static const struct file_operations wdt_fops = { 307 .owner = THIS_MODULE, 308 .llseek = no_llseek, 309 .write = fop_write, 310 .open = fop_open, 311 .release = fop_close, 312 .unlocked_ioctl = fop_ioctl, 313}; 314 315static struct miscdevice wdt_miscdev = { 316 .minor = WATCHDOG_MINOR, 317 .name = "watchdog", 318 .fops = &wdt_fops, 319}; 320 321/* 322 * Notifier for system down 323 */ 324 325static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 326 void *unused) 327{ 328 if (code == SYS_DOWN || code == SYS_HALT) 329 wdt_turnoff(); 330 return NOTIFY_DONE; 331} 332 333/* 334 * The WDT needs to learn about soft shutdowns in order to 335 * turn the timebomb registers off. 336 */ 337 338static struct notifier_block wdt_notifier = { 339 .notifier_call = wdt_notify_sys, 340}; 341 342static void __exit w83877f_wdt_unload(void) 343{ 344 wdt_turnoff(); 345 346 /* Deregister */ 347 misc_deregister(&wdt_miscdev); 348 349 unregister_reboot_notifier(&wdt_notifier); 350 release_region(WDT_PING, 1); 351 release_region(ENABLE_W83877F_PORT, 2); 352} 353 354static int __init w83877f_wdt_init(void) 355{ 356 int rc = -EBUSY; 357 358 if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ 359 timeout = WATCHDOG_TIMEOUT; 360 printk(KERN_INFO PFX 361 "timeout value must be 1 <= x <= 3600, using %d\n", 362 timeout); 363 } 364 365 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) { 366 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", 367 ENABLE_W83877F_PORT); 368 rc = -EIO; 369 goto err_out; 370 } 371 372 if (!request_region(WDT_PING, 1, "W8387FF WDT")) { 373 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", 374 WDT_PING); 375 rc = -EIO; 376 goto err_out_region1; 377 } 378 379 rc = register_reboot_notifier(&wdt_notifier); 380 if (rc) { 381 printk(KERN_ERR PFX 382 "cannot register reboot notifier (err=%d)\n", rc); 383 goto err_out_region2; 384 } 385 386 rc = misc_register(&wdt_miscdev); 387 if (rc) { 388 printk(KERN_ERR PFX 389 "cannot register miscdev on minor=%d (err=%d)\n", 390 wdt_miscdev.minor, rc); 391 goto err_out_reboot; 392 } 393 394 printk(KERN_INFO PFX 395 "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", 396 timeout, nowayout); 397 398 return 0; 399 400err_out_reboot: 401 unregister_reboot_notifier(&wdt_notifier); 402err_out_region2: 403 release_region(WDT_PING, 1); 404err_out_region1: 405 release_region(ENABLE_W83877F_PORT, 2); 406err_out: 407 return rc; 408} 409 410module_init(w83877f_wdt_init); 411module_exit(w83877f_wdt_unload); 412 413MODULE_AUTHOR("Scott and Bill Jennings"); 414MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); 415MODULE_LICENSE("GPL"); 416MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 417