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 the driver offers 27 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT, 28 * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls 29 * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces 30 * added extra printk's for startup problems 31 * use module_param 32 * made timeout (the emulated heartbeat) a module_param 33 * made the keepalive ping an internal subroutine 34 * 35 * This WDT driver is different from most other Linux WDT 36 * drivers in that the driver will ping the watchdog by itself, 37 * because this particular WDT has a very short timeout (1.6 38 * seconds) and it would be insane to count on any userspace 39 * daemon always getting scheduled within that time frame. 40 */ 41 42#include <linux/module.h> 43#include <linux/moduleparam.h> 44#include <linux/types.h> 45#include <linux/timer.h> 46#include <linux/jiffies.h> 47#include <linux/miscdevice.h> 48#include <linux/watchdog.h> 49#include <linux/fs.h> 50#include <linux/ioport.h> 51#include <linux/notifier.h> 52#include <linux/reboot.h> 53#include <linux/init.h> 54#include <asm/io.h> 55#include <asm/uaccess.h> 56#include <asm/system.h> 57 58#define OUR_NAME "w83877f_wdt" 59#define PFX OUR_NAME ": " 60 61#define ENABLE_W83877F_PORT 0x3F0 62#define ENABLE_W83877F 0x87 63#define DISABLE_W83877F 0xAA 64#define WDT_PING 0x443 65#define WDT_REGISTER 0x14 66#define WDT_ENABLE 0x9C 67#define WDT_DISABLE 0x8C 68 69/* 70 * The W83877F seems to be fixed at 1.6s timeout (at least on the 71 * EMACS PC-104 board I'm using). If we reset the watchdog every 72 * ~250ms we should be safe. */ 73 74#define WDT_INTERVAL (HZ/4+1) 75 76/* 77 * We must not require too good response from the userspace daemon. 78 * Here we require the userspace daemon to send us a heartbeat 79 * char to /dev/watchdog every 30 seconds. 80 */ 81 82#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ 83static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ 84module_param(timeout, int, 0); 85MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 86 87 88static int nowayout = WATCHDOG_NOWAYOUT; 89module_param(nowayout, int, 0); 90MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 91 92static void wdt_timer_ping(unsigned long); 93static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); 94static unsigned long next_heartbeat; 95static unsigned long wdt_is_open; 96static char wdt_expect_close; 97static spinlock_t wdt_spinlock; 98 99/* 100 * Whack the dog 101 */ 102 103static void wdt_timer_ping(unsigned long data) 104{ 105 /* If we got a heartbeat pulse within the WDT_US_INTERVAL 106 * we agree to ping the WDT 107 */ 108 if(time_before(jiffies, next_heartbeat)) 109 { 110 /* Ping the WDT */ 111 spin_lock(&wdt_spinlock); 112 113 /* Ping the WDT by reading from WDT_PING */ 114 inb_p(WDT_PING); 115 116 /* Re-set the timer interval */ 117 mod_timer(&timer, jiffies + WDT_INTERVAL); 118 119 spin_unlock(&wdt_spinlock); 120 121 } else { 122 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); 123 } 124} 125 126/* 127 * Utility routines 128 */ 129 130static void wdt_change(int writeval) 131{ 132 unsigned long flags; 133 spin_lock_irqsave(&wdt_spinlock, flags); 134 135 /* buy some time */ 136 inb_p(WDT_PING); 137 138 /* make W83877F available */ 139 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); 140 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); 141 142 /* enable watchdog */ 143 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); 144 outb_p(writeval, ENABLE_W83877F_PORT+1); 145 146 /* lock the W8387FF away */ 147 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); 148 149 spin_unlock_irqrestore(&wdt_spinlock, flags); 150} 151 152static void wdt_startup(void) 153{ 154 next_heartbeat = jiffies + (timeout * HZ); 155 156 /* Start the timer */ 157 mod_timer(&timer, jiffies + WDT_INTERVAL); 158 159 wdt_change(WDT_ENABLE); 160 161 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); 162} 163 164static void wdt_turnoff(void) 165{ 166 /* Stop the timer */ 167 del_timer(&timer); 168 169 wdt_change(WDT_DISABLE); 170 171 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); 172} 173 174static void wdt_keepalive(void) 175{ 176 /* user land ping */ 177 next_heartbeat = jiffies + (timeout * HZ); 178} 179 180/* 181 * /dev/watchdog handling 182 */ 183 184static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) 185{ 186 /* See if we got the magic character 'V' and reload the timer */ 187 if(count) 188 { 189 if (!nowayout) 190 { 191 size_t ofs; 192 193 /* note: just in case someone wrote the magic character 194 * five months ago... */ 195 wdt_expect_close = 0; 196 197 /* scan to see whether or not we got the magic character */ 198 for(ofs = 0; ofs != count; ofs++) 199 { 200 char c; 201 if (get_user(c, buf + ofs)) 202 return -EFAULT; 203 if (c == 'V') 204 wdt_expect_close = 42; 205 } 206 } 207 208 /* someone wrote to us, we should restart timer */ 209 wdt_keepalive(); 210 } 211 return count; 212} 213 214static int fop_open(struct inode * inode, struct file * file) 215{ 216 /* Just in case we're already talking to someone... */ 217 if(test_and_set_bit(0, &wdt_is_open)) 218 return -EBUSY; 219 220 /* Good, fire up the show */ 221 wdt_startup(); 222 return nonseekable_open(inode, file); 223} 224 225static int fop_close(struct inode * inode, struct file * file) 226{ 227 if(wdt_expect_close == 42) 228 wdt_turnoff(); 229 else { 230 del_timer(&timer); 231 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n"); 232 } 233 clear_bit(0, &wdt_is_open); 234 wdt_expect_close = 0; 235 return 0; 236} 237 238static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 239 unsigned long arg) 240{ 241 void __user *argp = (void __user *)arg; 242 int __user *p = argp; 243 static struct watchdog_info ident= 244 { 245 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, 246 .firmware_version = 1, 247 .identity = "W83877F", 248 }; 249 250 switch(cmd) 251 { 252 default: 253 return -ENOTTY; 254 case WDIOC_GETSUPPORT: 255 return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; 256 case WDIOC_GETSTATUS: 257 case WDIOC_GETBOOTSTATUS: 258 return put_user(0, p); 259 case WDIOC_KEEPALIVE: 260 wdt_keepalive(); 261 return 0; 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_SETTIMEOUT: 282 { 283 int new_timeout; 284 285 if(get_user(new_timeout, p)) 286 return -EFAULT; 287 288 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */ 289 return -EINVAL; 290 291 timeout = new_timeout; 292 wdt_keepalive(); 293 /* Fall through */ 294 } 295 case WDIOC_GETTIMEOUT: 296 return put_user(timeout, p); 297 } 298} 299 300static const struct file_operations wdt_fops = { 301 .owner = THIS_MODULE, 302 .llseek = no_llseek, 303 .write = fop_write, 304 .open = fop_open, 305 .release = fop_close, 306 .ioctl = fop_ioctl, 307}; 308 309static struct miscdevice wdt_miscdev = { 310 .minor = WATCHDOG_MINOR, 311 .name = "watchdog", 312 .fops = &wdt_fops, 313}; 314 315/* 316 * Notifier for system down 317 */ 318 319static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 320 void *unused) 321{ 322 if(code==SYS_DOWN || code==SYS_HALT) 323 wdt_turnoff(); 324 return NOTIFY_DONE; 325} 326 327/* 328 * The WDT needs to learn about soft shutdowns in order to 329 * turn the timebomb registers off. 330 */ 331 332static struct notifier_block wdt_notifier= 333{ 334 .notifier_call = wdt_notify_sys, 335}; 336 337static void __exit w83877f_wdt_unload(void) 338{ 339 wdt_turnoff(); 340 341 /* Deregister */ 342 misc_deregister(&wdt_miscdev); 343 344 unregister_reboot_notifier(&wdt_notifier); 345 release_region(WDT_PING,1); 346 release_region(ENABLE_W83877F_PORT,2); 347} 348 349static int __init w83877f_wdt_init(void) 350{ 351 int rc = -EBUSY; 352 353 spin_lock_init(&wdt_spinlock); 354 355 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */ 356 { 357 timeout = WATCHDOG_TIMEOUT; 358 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n", 359 timeout); 360 } 361 362 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) 363 { 364 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", 365 ENABLE_W83877F_PORT); 366 rc = -EIO; 367 goto err_out; 368 } 369 370 if (!request_region(WDT_PING, 1, "W8387FF WDT")) 371 { 372 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", 373 WDT_PING); 374 rc = -EIO; 375 goto err_out_region1; 376 } 377 378 rc = misc_register(&wdt_miscdev); 379 if (rc) 380 { 381 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", 382 wdt_miscdev.minor, rc); 383 goto err_out_region2; 384 } 385 386 rc = register_reboot_notifier(&wdt_notifier); 387 if (rc) 388 { 389 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", 390 rc); 391 goto err_out_miscdev; 392 } 393 394 printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", 395 timeout, nowayout); 396 397 return 0; 398 399err_out_miscdev: 400 misc_deregister(&wdt_miscdev); 401err_out_region2: 402 release_region(WDT_PING,1); 403err_out_region1: 404 release_region(ENABLE_W83877F_PORT,2); 405err_out: 406 return rc; 407} 408 409module_init(w83877f_wdt_init); 410module_exit(w83877f_wdt_unload); 411 412MODULE_AUTHOR("Scott and Bill Jennings"); 413MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); 414MODULE_LICENSE("GPL"); 415MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 416