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 two functions w83697hf_get_reg() and w83697hf_set_reg()
  87  *      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_select_wdt(void)
 106 {
 107         w83697hf_unlock();
 108         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
 109 }
 110
 111 static inline void
 112 w83697hf_deselect_wdt(void)
 113 {
 114         w83697hf_lock();
 115 }
 116
 117 static void
 118 w83697hf_select_wd_register(void)
 119 {
 120         w83697hf_unlock();
 121
 122         w83697hf_set_reg(0x29, 0x20);   /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
 123
 124         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
 125         w83697hf_set_reg(0x30, 0x01);   /* Enable timer/activate GPIO2 via bit 0 */
 126 }
 127
 128 static void
 129 w83697hf_unselect_wd_register(void)
 130 {
 131         w83697hf_lock();
 132 }
 133
 134 static void
 135 w83697hf_init(void)
 136 {
 137         unsigned char t;
 138
 139         w83697hf_select_wd_register();
 140
 141         t = w83697hf_get_reg(0xF3);     /* Read CRF3 */
 142         if (t != 0) {
 143                 printk (KERN_INFO PFX "Watchdog already running. Resetting timeout to %d sec\n", timeout);
 144                 w83697hf_set_reg(0xF3, timeout);        /* Write new timeout */
 145         }
 146         t = w83697hf_get_reg(0xF4);     /* Read CRF4 */
 147         t&=~0x0C;                       /* set second mode & disable keyboard turning off watchdog */
 148         w83697hf_set_reg(0xF4, t);      /* Write back to CRF4 */
 149
 150         w83697hf_unselect_wd_register();
 151 }
 152
 153 static void
 154 wdt_ctrl(int timeout)
 155 {
 156         spin_lock(&io_lock);
 157
 158         w83697hf_select_wdt();
 159
 160         w83697hf_set_reg(0xF4, timeout);        /* Write Timeout counter to CRF4 */
 161
 162         w83697hf_deselect_wdt();
 163
 164         spin_unlock(&io_lock);
 165 }
 166
 167 static int
 168 wdt_ping(void)
 169 {
 170         wdt_ctrl(timeout);
 171         return 0;
 172 }
 173
 174 static int
 175 wdt_disable(void)
 176 {
 177         wdt_ctrl(0);
 178         return 0;
 179 }
 180
 181 static int
 182 wdt_set_heartbeat(int t)
 183 {
 184         if ((t < 1) || (t > 255))
 185                 return -EINVAL;
 186
 187         timeout = t;
 188         return 0;
 189 }
 190
 191 static ssize_t
 192 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 193 {
 194         if (count) {
 195                 if (!nowayout) {
 196                         size_t i;
 197
 198                         expect_close = 0;
 199
 200                         for (i = 0; i != count; i++) {
 201                                 char c;
 202                                 if (get_user(c, buf+i))
 203                                         return -EFAULT;
 204                                 if (c == 'V')
 205                                         expect_close = 42;
 206                         }
 207                 }
 208                 wdt_ping();
 209         }
 210         return count;
 211 }
 212
 213 static int
 214 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 215           unsigned long arg)
 216 {
 217         void __user *argp = (void __user *)arg;
 218         int __user *p = argp;
 219         int new_timeout;
 220         static struct watchdog_info ident = {
 221                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 222                 .firmware_version = 1,
 223                 .identity = "W83697HF WDT",
 224         };
 225
 226         switch (cmd) {
 227         case WDIOC_GETSUPPORT:
 228                 if (copy_to_user(argp, &ident, sizeof(ident)))
 229                         return -EFAULT;
 230                 break;
 231
 232         case WDIOC_GETSTATUS:
 233         case WDIOC_GETBOOTSTATUS:
 234                 return put_user(0, p);
 235
 236         case WDIOC_KEEPALIVE:
 237                 wdt_ping();
 238                 break;
 239
 240         case WDIOC_SETTIMEOUT:
 241                 if (get_user(new_timeout, p))
 242                         return -EFAULT;
 243                 if (wdt_set_heartbeat(new_timeout))
 244                         return -EINVAL;
 245                 wdt_ping();
 246                 /* Fall */
 247
 248         case WDIOC_GETTIMEOUT:
 249                 return put_user(timeout, p);
 250
 251         case WDIOC_SETOPTIONS:
 252         {
 253                 int options, retval = -EINVAL;
 254
 255                 if (get_user(options, p))
 256                         return -EFAULT;
 257
 258                 if (options & WDIOS_DISABLECARD) {
 259                         wdt_disable();
 260                         retval = 0;
 261                 }
 262
 263                 if (options & WDIOS_ENABLECARD) {
 264                         wdt_ping();
 265                         retval = 0;
 266                 }
 267
 268                 return retval;
 269         }
 270
 271         default:
 272                 return -ENOTTY;
 273         }
 274         return 0;
 275 }
 276
 277 static int
 278 wdt_open(struct inode *inode, struct file *file)
 279 {
 280         if (test_and_set_bit(0, &wdt_is_open))
 281                 return -EBUSY;
 282         /*
 283          *      Activate
 284          */
 285
 286         wdt_ping();
 287         return nonseekable_open(inode, file);
 288 }
 289
 290 static int
 291 wdt_close(struct inode *inode, struct file *file)
 292 {
 293         if (expect_close == 42) {
 294                 wdt_disable();
 295         } else {
 296                 printk (KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 297                 wdt_ping();
 298         }
 299         expect_close = 0;
 300         clear_bit(0, &wdt_is_open);
 301         return 0;
 302 }
 303
 304 /*
 305  *      Notifier for system down
 306  */
 307
 308 static int
 309 wdt_notify_sys(struct notifier_block *this, unsigned long code,
 310         void *unused)
 311 {
 312         if (code == SYS_DOWN || code == SYS_HALT) {
 313                 /* Turn the WDT off */
 314                 wdt_disable();
 315         }
 316         return NOTIFY_DONE;
 317 }
 318
 319 /*
 320  *      Kernel Interfaces
 321  */
 322
 323 static struct file_operations wdt_fops = {
 324         .owner          = THIS_MODULE,
 325         .llseek         = no_llseek,
 326         .write          = wdt_write,
 327         .ioctl          = wdt_ioctl,
 328         .open           = wdt_open,
 329         .release        = wdt_close,
 330 };
 331
 332 static struct miscdevice wdt_miscdev = {
 333         .minor = WATCHDOG_MINOR,
 334         .name = "watchdog",
 335         .fops = &wdt_fops,
 336 };
 337
 338 /*
 339  *      The WDT needs to learn about soft shutdowns in order to
 340  *      turn the timebomb registers off.
 341  */
 342
 343 static struct notifier_block wdt_notifier = {
 344         .notifier_call = wdt_notify_sys,
 345 };
 346
 347 static int
 348 w83697hf_check_wdt(void)
 349 {
 350         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
 351                 printk (KERN_ERR PFX "I/O address 0x%x already in use\n", wdt_io);
 352                 return -EIO;
 353         }
 354
 355         printk (KERN_DEBUG PFX "Looking for watchdog at address 0x%x\n", wdt_io);
 356         w83697hf_unlock();
 357         if (w83697hf_get_reg(0x20) == 0x60) {
 358                 printk (KERN_INFO PFX "watchdog found at address 0x%x\n", wdt_io);
 359                 w83697hf_lock();
 360                 return 0;
 361         }
 362         w83697hf_lock();        /* Reprotect in case it was a compatible device */
 363
 364         printk (KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
 365         release_region(wdt_io, 2);
 366         return -EIO;
 367 }
 368
 369 static int __init
 370 wdt_init(void)
 371 {
 372         int ret, autodetect;
 373
 374         spin_lock_init(&io_lock);
 375
 376         printk (KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");
 377
 378         autodetect = wdt_io == 0;
 379         if (autodetect)
 380                 wdt_io = 0x2e;
 381
 382         if (!w83697hf_check_wdt())
 383                 goto found;
 384
 385         if (autodetect) {
 386                 wdt_io = 0x4e;
 387                 if (!w83697hf_check_wdt())
 388                         goto found;
 389         }
 390
 391         printk (KERN_ERR PFX "No W83697HF/HG could be found\n");
 392         ret = -EIO;
 393         goto out;
 394
 395 found:
 396
 397         if (wdt_set_heartbeat(timeout)) {
 398                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 399                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=255, using %d\n",
 400                         WATCHDOG_TIMEOUT);
 401         }
 402
 403         w83697hf_init();
 404
 405         ret = register_reboot_notifier(&wdt_notifier);
 406         if (ret != 0) {
 407                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 408                         ret);
 409                 goto unreg_regions;
 410         }
 411
 412         ret = misc_register(&wdt_miscdev);
 413         if (ret != 0) {
 414                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 415                         WATCHDOG_MINOR, ret);
 416                 goto unreg_reboot;
 417         }
 418
 419         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 420                 timeout, nowayout);
 421
 422 out:
 423         return ret;
 424 unreg_reboot:
 425         unregister_reboot_notifier(&wdt_notifier);
 426 unreg_regions:
 427         release_region(wdt_io, 2);
 428         goto out;
 429 }
 430
 431 static void __exit
 432 wdt_exit(void)
 433 {
 434         misc_deregister(&wdt_miscdev);
 435         unregister_reboot_notifier(&wdt_notifier);
 436         release_region(wdt_io, 2);
 437 }
 438
 439 module_init(wdt_init);
 440 module_exit(wdt_exit);
 441
 442 MODULE_LICENSE("GPL");
 443 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
 444 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
 445 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);