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