drivers/watchdog/w83697hf_wdt.c

   1 /*
   2  *      w83697hf/hg WDT driver
   3  *
   4  *      (c) Copyright 2006 Samuel Tardieu <sam@rfc1149.net>
   5  *      (c) Copyright 2006 Marcus Junker <junker@anduras.de>
   6  *
   7  *      Based on w83627hf_wdt.c which is based on advantechwdt.c
   8  *      which is based on wdt.c.
   9  *      Original copyright messages:
  10  *
  11  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  12  *
  13  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  14  *
  15  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  16  *                                              All Rights Reserved.
  17  *
  18  *      This program is free software; you can redistribute it and/or
  19  *      modify it under the terms of the GNU General Public License
  20  *      as published by the Free Software Foundation; either version
  21  *      2 of the License, or (at your option) any later version.
  22  *
  23  *      Neither Marcus Junker nor ANDURAS AG admit liability nor provide
  24  *      warranty for any of this software. This material is provided
  25  *      "AS-IS" and at no charge.
  26  */
  27
  28 #include <linux/module.h>
  29 #include <linux/moduleparam.h>
  30 #include <linux/types.h>
  31 #include <linux/miscdevice.h>
  32 #include <linux/watchdog.h>
  33 #include <linux/fs.h>
  34 #include <linux/ioport.h>
  35 #include <linux/notifier.h>
  36 #include <linux/reboot.h>
  37 #include <linux/init.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/io.h>
  40 #include <linux/uaccess.h>
  41
  42
  43 #define WATCHDOG_NAME "w83697hf/hg WDT"
  44 #define PFX WATCHDOG_NAME ": "
  45 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  46 #define WATCHDOG_EARLY_DISABLE 1        /* Disable until userland kicks in */
  47
  48 static unsigned long wdt_is_open;
  49 static char expect_close;
  50 static DEFINE_SPINLOCK(io_lock);
  51
  52 /* You must set this - there is no sane way to probe for this board. */
  53 static int wdt_io = 0x2e;
  54 module_param(wdt_io, int, 0);
  55 MODULE_PARM_DESC(wdt_io,
  56                 "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
  57
  58 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  59 module_param(timeout, int, 0);
  60 MODULE_PARM_DESC(timeout,
  61         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
  62                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  63
  64 static int nowayout = WATCHDOG_NOWAYOUT;
  65 module_param(nowayout, int, 0);
  66 MODULE_PARM_DESC(nowayout,
  67         "Watchdog cannot be stopped once started (default="
  68                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  69
  70 static int early_disable = WATCHDOG_EARLY_DISABLE;
  71 module_param(early_disable, int, 0);
  72 MODULE_PARM_DESC(early_disable,
  73         "Watchdog gets disabled at boot time (default="
  74                                 __MODULE_STRING(WATCHDOG_EARLY_DISABLE) ")");
  75
  76 /*
  77  *      Kernel methods.
  78  */
  79
  80 #define W83697HF_EFER (wdt_io + 0)  /* Extended Function Enable Register */
  81 #define W83697HF_EFIR (wdt_io + 0)  /* Extended Function Index Register
  82                                                         (same as EFER) */
  83 #define W83697HF_EFDR (wdt_io + 1)  /* Extended Function Data Register */
  84
  85 static inline void w83697hf_unlock(void)
  86 {
  87         outb_p(0x87, W83697HF_EFER);    /* Enter extended function mode */
  88         outb_p(0x87, W83697HF_EFER);    /* Again according to manual */
  89 }
  90
  91 static inline void w83697hf_lock(void)
  92 {
  93         outb_p(0xAA, W83697HF_EFER);    /* Leave extended function mode */
  94 }
  95
  96 /*
  97  *      The three functions w83697hf_get_reg(), w83697hf_set_reg() and
  98  *      w83697hf_write_timeout() must be called with the device unlocked.
  99  */
 100
 101 static unsigned char w83697hf_get_reg(unsigned char reg)
 102 {
 103         outb_p(reg, W83697HF_EFIR);
 104         return inb_p(W83697HF_EFDR);
 105 }
 106
 107 static void w83697hf_set_reg(unsigned char reg, unsigned char data)
 108 {
 109         outb_p(reg, W83697HF_EFIR);
 110         outb_p(data, W83697HF_EFDR);
 111 }
 112
 113 static void w83697hf_write_timeout(int timeout)
 114 {
 115         /* Write Timeout counter to CRF4 */
 116         w83697hf_set_reg(0xF4, timeout);
 117 }
 118
 119 static void w83697hf_select_wdt(void)
 120 {
 121         w83697hf_unlock();
 122         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
 123 }
 124
 125 static inline void w83697hf_deselect_wdt(void)
 126 {
 127         w83697hf_lock();
 128 }
 129
 130 static void w83697hf_init(void)
 131 {
 132         unsigned char bbuf;
 133
 134         w83697hf_select_wdt();
 135
 136         bbuf = w83697hf_get_reg(0x29);
 137         bbuf &= ~0x60;
 138         bbuf |= 0x20;
 139
 140         /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
 141         w83697hf_set_reg(0x29, bbuf);
 142
 143         bbuf = w83697hf_get_reg(0xF3);
 144         bbuf &= ~0x04;
 145         w83697hf_set_reg(0xF3, bbuf);   /* Count mode is seconds */
 146
 147         w83697hf_deselect_wdt();
 148 }
 149
 150 static void wdt_ping(void)
 151 {
 152         spin_lock(&io_lock);
 153         w83697hf_select_wdt();
 154
 155         w83697hf_write_timeout(timeout);
 156
 157         w83697hf_deselect_wdt();
 158         spin_unlock(&io_lock);
 159 }
 160
 161 static void wdt_enable(void)
 162 {
 163         spin_lock(&io_lock);
 164         w83697hf_select_wdt();
 165
 166         w83697hf_write_timeout(timeout);
 167         w83697hf_set_reg(0x30, 1);      /* Enable timer */
 168
 169         w83697hf_deselect_wdt();
 170         spin_unlock(&io_lock);
 171 }
 172
 173 static void wdt_disable(void)
 174 {
 175         spin_lock(&io_lock);
 176         w83697hf_select_wdt();
 177
 178         w83697hf_set_reg(0x30, 0);      /* Disable timer */
 179         w83697hf_write_timeout(0);
 180
 181         w83697hf_deselect_wdt();
 182         spin_unlock(&io_lock);
 183 }
 184
 185 static unsigned char wdt_running(void)
 186 {
 187         unsigned char t;
 188
 189         spin_lock(&io_lock);
 190         w83697hf_select_wdt();
 191
 192         t = w83697hf_get_reg(0xF4);     /* Read timer */
 193
 194         w83697hf_deselect_wdt();
 195         spin_unlock(&io_lock);
 196
 197         return t;
 198 }
 199
 200 static int wdt_set_heartbeat(int t)
 201 {
 202         if (t < 1 || t > 255)
 203                 return -EINVAL;
 204
 205         timeout = t;
 206         return 0;
 207 }
 208
 209 static ssize_t wdt_write(struct file *file, const char __user *buf,
 210                                                 size_t count, loff_t *ppos)
 211 {
 212         if (count) {
 213                 if (!nowayout) {
 214                         size_t i;
 215
 216                         expect_close = 0;
 217
 218                         for (i = 0; i != count; i++) {
 219                                 char c;
 220                                 if (get_user(c, buf + i))
 221                                         return -EFAULT;
 222                                 if (c == 'V')
 223                                         expect_close = 42;
 224                         }
 225                 }
 226                 wdt_ping();
 227         }
 228         return count;
 229 }
 230
 231 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 232 {
 233         void __user *argp = (void __user *)arg;
 234         int __user *p = argp;
 235         int new_timeout;
 236         static const struct watchdog_info ident = {
 237                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 238                                                         | WDIOF_MAGICCLOSE,
 239                 .firmware_version = 1,
 240                 .identity = "W83697HF WDT",
 241         };
 242
 243         switch (cmd) {
 244         case WDIOC_GETSUPPORT:
 245                 if (copy_to_user(argp, &ident, sizeof(ident)))
 246                         return -EFAULT;
 247                 break;
 248
 249         case WDIOC_GETSTATUS:
 250         case WDIOC_GETBOOTSTATUS:
 251                 return put_user(0, p);
 252
 253         case WDIOC_SETOPTIONS:
 254         {
 255                 int options, retval = -EINVAL;
 256
 257                 if (get_user(options, p))
 258                         return -EFAULT;
 259
 260                 if (options & WDIOS_DISABLECARD) {
 261                         wdt_disable();
 262                         retval = 0;
 263                 }
 264
 265                 if (options & WDIOS_ENABLECARD) {
 266                         wdt_enable();
 267                         retval = 0;
 268                 }
 269
 270                 return retval;
 271         }
 272
 273         case WDIOC_KEEPALIVE:
 274                 wdt_ping();
 275                 break;
 276
 277         case WDIOC_SETTIMEOUT:
 278                 if (get_user(new_timeout, p))
 279                         return -EFAULT;
 280                 if (wdt_set_heartbeat(new_timeout))
 281                         return -EINVAL;
 282                 wdt_ping();
 283                 /* Fall */
 284
 285         case WDIOC_GETTIMEOUT:
 286                 return put_user(timeout, p);
 287
 288         default:
 289                 return -ENOTTY;
 290         }
 291         return 0;
 292 }
 293
 294 static int wdt_open(struct inode *inode, struct file *file)
 295 {
 296         if (test_and_set_bit(0, &wdt_is_open))
 297                 return -EBUSY;
 298         /*
 299          *      Activate
 300          */
 301
 302         wdt_enable();
 303         return nonseekable_open(inode, file);
 304 }
 305
 306 static int wdt_close(struct inode *inode, struct file *file)
 307 {
 308         if (expect_close == 42)
 309                 wdt_disable();
 310         else {
 311                 printk(KERN_CRIT PFX
 312                         "Unexpected close, not stopping watchdog!\n");
 313                 wdt_ping();
 314         }
 315         expect_close = 0;
 316         clear_bit(0, &wdt_is_open);
 317         return 0;
 318 }
 319
 320 /*
 321  *      Notifier for system down
 322  */
 323
 324 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 325         void *unused)
 326 {
 327         if (code == SYS_DOWN || code == SYS_HALT)
 328                 wdt_disable();  /* Turn the WDT off */
 329
 330         return NOTIFY_DONE;
 331 }
 332
 333 /*
 334  *      Kernel Interfaces
 335  */
 336
 337 static const struct file_operations wdt_fops = {
 338         .owner          = THIS_MODULE,
 339         .llseek         = no_llseek,
 340         .write          = wdt_write,
 341         .unlocked_ioctl = wdt_ioctl,
 342         .open           = wdt_open,
 343         .release        = wdt_close,
 344 };
 345
 346 static struct miscdevice wdt_miscdev = {
 347         .minor = WATCHDOG_MINOR,
 348         .name = "watchdog",
 349         .fops = &wdt_fops,
 350 };
 351
 352 /*
 353  *      The WDT needs to learn about soft shutdowns in order to
 354  *      turn the timebomb registers off.
 355  */
 356
 357 static struct notifier_block wdt_notifier = {
 358         .notifier_call = wdt_notify_sys,
 359 };
 360
 361 static int w83697hf_check_wdt(void)
 362 {
 363         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
 364                 printk(KERN_ERR PFX
 365                         "I/O address 0x%x already in use\n", wdt_io);
 366                 return -EIO;
 367         }
 368
 369         printk(KERN_DEBUG PFX
 370                         "Looking for watchdog at address 0x%x\n", wdt_io);
 371         w83697hf_unlock();
 372         if (w83697hf_get_reg(0x20) == 0x60) {
 373                 printk(KERN_INFO PFX
 374                         "watchdog found at address 0x%x\n", wdt_io);
 375                 w83697hf_lock();
 376                 return 0;
 377         }
 378         /* Reprotect in case it was a compatible device */
 379         w83697hf_lock();
 380
 381         printk(KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
 382         release_region(wdt_io, 2);
 383         return -EIO;
 384 }
 385
 386 static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
 387
 388 static int __init wdt_init(void)
 389 {
 390         int ret, i, found = 0;
 391
 392         printk(KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");
 393
 394         if (wdt_io == 0) {
 395                 /* we will autodetect the W83697HF/HG watchdog */
 396                 for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
 397                         wdt_io = w83697hf_ioports[i];
 398                         if (!w83697hf_check_wdt())
 399                                 found++;
 400                 }
 401         } else {
 402                 if (!w83697hf_check_wdt())
 403                         found++;
 404         }
 405
 406         if (!found) {
 407                 printk(KERN_ERR PFX "No W83697HF/HG could be found\n");
 408                 ret = -EIO;
 409                 goto out;
 410         }
 411
 412         w83697hf_init();
 413         if (early_disable) {
 414                 if (wdt_running())
 415                         printk(KERN_WARNING PFX "Stopping previously enabled "
 416                                         "watchdog until userland kicks in\n");
 417                 wdt_disable();
 418         }
 419
 420         if (wdt_set_heartbeat(timeout)) {
 421                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 422                 printk(KERN_INFO PFX
 423                      "timeout value must be 1 <= timeout <= 255, using %d\n",
 424                                                         WATCHDOG_TIMEOUT);
 425         }
 426
 427         ret = register_reboot_notifier(&wdt_notifier);
 428         if (ret != 0) {
 429                 printk(KERN_ERR PFX
 430                         "cannot register reboot notifier (err=%d)\n", ret);
 431                 goto unreg_regions;
 432         }
 433
 434         ret = misc_register(&wdt_miscdev);
 435         if (ret != 0) {
 436                 printk(KERN_ERR PFX
 437                         "cannot register miscdev on minor=%d (err=%d)\n",
 438                                                 WATCHDOG_MINOR, ret);
 439                 goto unreg_reboot;
 440         }
 441
 442         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 443                 timeout, nowayout);
 444
 445 out:
 446         return ret;
 447 unreg_reboot:
 448         unregister_reboot_notifier(&wdt_notifier);
 449 unreg_regions:
 450         release_region(wdt_io, 2);
 451         goto out;
 452 }
 453
 454 static void __exit wdt_exit(void)
 455 {
 456         misc_deregister(&wdt_miscdev);
 457         unregister_reboot_notifier(&wdt_notifier);
 458         release_region(wdt_io, 2);
 459 }
 460
 461 module_init(wdt_init);
 462 module_exit(wdt_exit);
 463
 464 MODULE_LICENSE("GPL");
 465 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, "
 466                 "Samuel Tardieu <sam@rfc1149.net>");
 467 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
 468 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);