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