drivers/char/watchdog/w83697hf_wdt.c

   1 /*
   2  *      w83697hf/hg WDT driver
   3  *
   4  *      (c) Copyright 2006 Marcus Junker <junker@anduras.de>
   5  *
   6  *      Based on w83627hf_wdt.c which is based on advantechwdt.c
   7  *      which is based on wdt.c.
   8  *      Original copyright messages:
   9  *
  10  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  11  *
  12  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  13  *
  14  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  15  *                              http://www.redhat.com
  16  *
  17  *      This program is free software; you can redistribute it and/or
  18  *      modify it under the terms of the GNU General Public License
  19  *      as published by the Free Software Foundation; either version
  20  *      2 of the License, or (at your option) any later version.
  21  *
  22  *      Neither Marcus Junker nor ANDURAS AG admit liability nor provide
  23  *      warranty for any of this software. This material is provided
  24  *      "AS-IS" and at no charge.
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/types.h>
  30 #include <linux/miscdevice.h>
  31 #include <linux/watchdog.h>
  32 #include <linux/fs.h>
  33 #include <linux/ioport.h>
  34 #include <linux/notifier.h>
  35 #include <linux/reboot.h>
  36 #include <linux/init.h>
  37 #include <linux/spinlock.h>
  38
  39 #include <asm/io.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/system.h>
  42
  43 #define WATCHDOG_NAME "w83697hf/hg WDT"
  44 #define PFX WATCHDOG_NAME ": "
  45 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  46
  47 static unsigned long wdt_is_open;
  48 static char expect_close;
  49 static spinlock_t io_lock;
  50
  51 /* You must set this - there is no sane way to probe for this board. */
  52 static int wdt_io = 0x2e;
  53 module_param(wdt_io, int, 0);
  54 MODULE_PARM_DESC(wdt_io, "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
  55
  56 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  57 module_param(timeout, int, 0);
  58 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  59
  60 static int nowayout = WATCHDOG_NOWAYOUT;
  61 module_param(nowayout, int, 0);
  62 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  63
  64 /*
  65  *      Kernel methods.
  66  */
  67
  68 #define W83697HF_EFER (wdt_io+0)        /* Extended Function Enable Register */
  69 #define W83697HF_EFIR (wdt_io+0)        /* Extended Function Index Register (same as EFER) */
  70 #define W83697HF_EFDR (wdt_io+1)        /* Extended Function Data Register */
  71
  72 static inline void
  73 w83697hf_unlock(void)
  74 {
  75         outb_p(0x87, W83697HF_EFER);    /* Enter extended function mode */
  76         outb_p(0x87, W83697HF_EFER);    /* Again according to manual */
  77 }
  78
  79 static inline void
  80 w83697hf_lock(void)
  81 {
  82         outb_p(0xAA, W83697HF_EFER);    /* Leave extended function mode */
  83 }
  84
  85 /*
  86  *      The three functions w83697hf_get_reg(), w83697hf_set_reg() and
  87  *      w83697hf_write_timeout() must be called with the device unlocked.
  88  */
  89
  90 static unsigned char
  91 w83697hf_get_reg(unsigned char reg)
  92 {
  93         outb_p(reg, W83697HF_EFIR);
  94         return inb_p(W83697HF_EFDR);
  95 }
  96
  97 static void
  98 w83697hf_set_reg(unsigned char reg, unsigned char data)
  99 {
 100         outb_p(reg, W83697HF_EFIR);
 101         outb_p(data, W83697HF_EFDR);
 102 }
 103
 104 static void
 105 w83697hf_write_timeout(int timeout)
 106 {
 107         w83697hf_set_reg(0xF4, timeout);        /* Write Timeout counter to CRF4 */
 108 }
 109
 110 static void
 111 w83697hf_select_wdt(void)
 112 {
 113         w83697hf_unlock();
 114         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
 115 }
 116
 117 static inline void
 118 w83697hf_deselect_wdt(void)
 119 {
 120         w83697hf_lock();
 121 }
 122
 123 static void
 124 w83697hf_init(void)
 125 {
 126         unsigned char t;
 127
 128         w83697hf_select_wdt();
 129
 130         w83697hf_set_reg(0x29, 0x20);   /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
 131
 132         t = w83697hf_get_reg(0xF3);     /* Read CRF3 */
 133         if (t != 0) {
 134                 printk (KERN_INFO PFX "Watchdog already running. Resetting timeout to %d sec\n", timeout);
 135                 w83697hf_set_reg(0xF3, timeout);        /* Write new timeout */
 136         }
 137         t = w83697hf_get_reg(0xF4);     /* Read CRF4 */
 138         t&=~0x0C;                       /* set second mode & disable keyboard turning off watchdog */
 139         w83697hf_set_reg(0xF4, t);      /* Write back to CRF4 */
 140
 141         w83697hf_deselect_wdt();
 142 }
 143
 144 static int
 145 wdt_ping(void)
 146 {
 147         spin_lock(&io_lock);
 148         w83697hf_select_wdt();
 149
 150         w83697hf_write_timeout(timeout);
 151
 152         w83697hf_deselect_wdt();
 153         spin_unlock(&io_lock);
 154         return 0;
 155 }
 156
 157 static int
 158 wdt_enable(void)
 159 {
 160         spin_lock(&io_lock);
 161         w83697hf_select_wdt();
 162
 163         w83697hf_write_timeout(timeout);
 164         w83697hf_set_reg(0x30, 1);      /* Enable timer */
 165
 166         w83697hf_deselect_wdt();
 167         spin_unlock(&io_lock);
 168         return 0;
 169 }
 170
 171 static int
 172 wdt_disable(void)
 173 {
 174         spin_lock(&io_lock);
 175         w83697hf_select_wdt();
 176
 177         w83697hf_set_reg(0x30, 0);      /* Disable timer */
 178         w83697hf_write_timeout(0);
 179
 180         w83697hf_deselect_wdt();
 181         spin_unlock(&io_lock);
 182         return 0;
 183 }
 184
 185 static int
 186 wdt_set_heartbeat(int t)
 187 {
 188         if ((t < 1) || (t > 255))
 189                 return -EINVAL;
 190
 191         timeout = t;
 192         return 0;
 193 }
 194
 195 static ssize_t
 196 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 197 {
 198         if (count) {
 199                 if (!nowayout) {
 200                         size_t i;
 201
 202                         expect_close = 0;
 203
 204                         for (i = 0; i != count; i++) {
 205                                 char c;
 206                                 if (get_user(c, buf+i))
 207                                         return -EFAULT;
 208                                 if (c == 'V')
 209                                         expect_close = 42;
 210                         }
 211                 }
 212                 wdt_ping();
 213         }
 214         return count;
 215 }
 216
 217 static int
 218 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 219           unsigned long arg)
 220 {
 221         void __user *argp = (void __user *)arg;
 222         int __user *p = argp;
 223         int new_timeout;
 224         static struct watchdog_info ident = {
 225                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 226                 .firmware_version = 1,
 227                 .identity = "W83697HF WDT",
 228         };
 229
 230         switch (cmd) {
 231         case WDIOC_GETSUPPORT:
 232                 if (copy_to_user(argp, &ident, sizeof(ident)))
 233                         return -EFAULT;
 234                 break;
 235
 236         case WDIOC_GETSTATUS:
 237         case WDIOC_GETBOOTSTATUS:
 238                 return put_user(0, p);
 239
 240         case WDIOC_KEEPALIVE:
 241                 wdt_ping();
 242                 break;
 243
 244         case WDIOC_SETTIMEOUT:
 245                 if (get_user(new_timeout, p))
 246                         return -EFAULT;
 247                 if (wdt_set_heartbeat(new_timeout))
 248                         return -EINVAL;
 249                 wdt_ping();
 250                 /* Fall */
 251
 252         case WDIOC_GETTIMEOUT:
 253                 return put_user(timeout, p);
 254
 255         case WDIOC_SETOPTIONS:
 256         {
 257                 int options, retval = -EINVAL;
 258
 259                 if (get_user(options, p))
 260                         return -EFAULT;
 261
 262                 if (options & WDIOS_DISABLECARD) {
 263                         wdt_disable();
 264                         retval = 0;
 265                 }
 266
 267                 if (options & WDIOS_ENABLECARD) {
 268                         wdt_enable();
 269                         retval = 0;
 270                 }
 271
 272                 return retval;
 273         }
 274
 275         default:
 276                 return -ENOTTY;
 277         }
 278         return 0;
 279 }
 280
 281 static int
 282 wdt_open(struct inode *inode, struct file *file)
 283 {
 284         if (test_and_set_bit(0, &wdt_is_open))
 285                 return -EBUSY;
 286         /*
 287          *      Activate
 288          */
 289
 290         wdt_enable();
 291         return nonseekable_open(inode, file);
 292 }
 293
 294 static int
 295 wdt_close(struct inode *inode, struct file *file)
 296 {
 297         if (expect_close == 42) {
 298                 wdt_disable();
 299         } else {
 300                 printk (KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 301                 wdt_ping();
 302         }
 303         expect_close = 0;
 304         clear_bit(0, &wdt_is_open);
 305         return 0;
 306 }
 307
 308 /*
 309  *      Notifier for system down
 310  */
 311
 312 static int
 313 wdt_notify_sys(struct notifier_block *this, unsigned long code,
 314         void *unused)
 315 {
 316         if (code == SYS_DOWN || code == SYS_HALT) {
 317                 /* Turn the WDT off */
 318                 wdt_disable();
 319         }
 320         return NOTIFY_DONE;
 321 }
 322
 323 /*
 324  *      Kernel Interfaces
 325  */
 326
 327 static struct file_operations wdt_fops = {
 328         .owner          = THIS_MODULE,
 329         .llseek         = no_llseek,
 330         .write          = wdt_write,
 331         .ioctl          = wdt_ioctl,
 332         .open           = wdt_open,
 333         .release        = wdt_close,
 334 };
 335
 336 static struct miscdevice wdt_miscdev = {
 337         .minor = WATCHDOG_MINOR,
 338         .name = "watchdog",
 339         .fops = &wdt_fops,
 340 };
 341
 342 /*
 343  *      The WDT needs to learn about soft shutdowns in order to
 344  *      turn the timebomb registers off.
 345  */
 346
 347 static struct notifier_block wdt_notifier = {
 348         .notifier_call = wdt_notify_sys,
 349 };
 350
 351 static int
 352 w83697hf_check_wdt(void)
 353 {
 354         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
 355                 printk (KERN_ERR PFX "I/O address 0x%x already in use\n", wdt_io);
 356                 return -EIO;
 357         }
 358
 359         printk (KERN_DEBUG PFX "Looking for watchdog at address 0x%x\n", wdt_io);
 360         w83697hf_unlock();
 361         if (w83697hf_get_reg(0x20) == 0x60) {
 362                 printk (KERN_INFO PFX "watchdog found at address 0x%x\n", wdt_io);
 363                 w83697hf_lock();
 364                 return 0;
 365         }
 366         w83697hf_lock();        /* Reprotect in case it was a compatible device */
 367
 368         printk (KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
 369         release_region(wdt_io, 2);
 370         return -EIO;
 371 }
 372
 373 static int __init
 374 wdt_init(void)
 375 {
 376         int ret, autodetect;
 377
 378         spin_lock_init(&io_lock);
 379
 380         printk (KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");
 381
 382         autodetect = wdt_io == 0;
 383         if (autodetect)
 384                 wdt_io = 0x2e;
 385
 386         if (!w83697hf_check_wdt())
 387                 goto found;
 388
 389         if (autodetect) {
 390                 wdt_io = 0x4e;
 391                 if (!w83697hf_check_wdt())
 392                         goto found;
 393         }
 394
 395         printk (KERN_ERR PFX "No W83697HF/HG could be found\n");
 396         ret = -EIO;
 397         goto out;
 398
 399 found:
 400         w83697hf_init();
 401         wdt_disable();  /* Disable watchdog until first use */
 402
 403         if (wdt_set_heartbeat(timeout)) {
 404                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 405                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=255, using %d\n",
 406                         WATCHDOG_TIMEOUT);
 407         }
 408
 409         ret = register_reboot_notifier(&wdt_notifier);
 410         if (ret != 0) {
 411                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 412                         ret);
 413                 goto unreg_regions;
 414         }
 415
 416         ret = misc_register(&wdt_miscdev);
 417         if (ret != 0) {
 418                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 419                         WATCHDOG_MINOR, ret);
 420                 goto unreg_reboot;
 421         }
 422
 423         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 424                 timeout, nowayout);
 425
 426 out:
 427         return ret;
 428 unreg_reboot:
 429         unregister_reboot_notifier(&wdt_notifier);
 430 unreg_regions:
 431         release_region(wdt_io, 2);
 432         goto out;
 433 }
 434
 435 static void __exit
 436 wdt_exit(void)
 437 {
 438         misc_deregister(&wdt_miscdev);
 439         unregister_reboot_notifier(&wdt_notifier);
 440         release_region(wdt_io, 2);
 441 }
 442
 443 module_init(wdt_init);
 444 module_exit(wdt_exit);
 445
 446 MODULE_LICENSE("GPL");
 447 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
 448 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
 449 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);