drivers/watchdog/w83697ug_wdt.c

   1 /*
   2  *      w83697ug/uf WDT driver
   3  *
   4  *      (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
   5  *              reused original code to support w83697ug/uf.
   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 2007 Vlad Drukker <vlad@storewiz.com>
  12  *              added support for W83627THF.
  13  *
  14  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  15  *
  16  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  17  *
  18  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  19  *                              http://www.redhat.com
  20  *
  21  *      This program is free software; you can redistribute it and/or
  22  *      modify it under the terms of the GNU General Public License
  23  *      as published by the Free Software Foundation; either version
  24  *      2 of the License, or (at your option) any later version.
  25  *
  26  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  27  *      warranty for any of this software. This material is provided
  28  *      "AS-IS" and at no charge.
  29  *
  30  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  31  */
  32
  33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  34
  35 #include <linux/module.h>
  36 #include <linux/moduleparam.h>
  37 #include <linux/types.h>
  38 #include <linux/miscdevice.h>
  39 #include <linux/watchdog.h>
  40 #include <linux/fs.h>
  41 #include <linux/ioport.h>
  42 #include <linux/notifier.h>
  43 #include <linux/reboot.h>
  44 #include <linux/init.h>
  45 #include <linux/spinlock.h>
  46 #include <linux/io.h>
  47 #include <linux/uaccess.h>
  48
  49 #include <asm/system.h>
  50
  51 #define WATCHDOG_NAME "w83697ug/uf WDT"
  52 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  53
  54 static unsigned long wdt_is_open;
  55 static char expect_close;
  56 static DEFINE_SPINLOCK(io_lock);
  57
  58 static int wdt_io = 0x2e;
  59 module_param(wdt_io, int, 0);
  60 MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
  61
  62 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  63 module_param(timeout, int, 0);
  64 MODULE_PARM_DESC(timeout,
  65         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
  66                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  67
  68 static bool nowayout = WATCHDOG_NOWAYOUT;
  69 module_param(nowayout, bool, 0);
  70 MODULE_PARM_DESC(nowayout,
  71         "Watchdog cannot be stopped once started (default="
  72                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  73
  74 /*
  75  *      Kernel methods.
  76  */
  77
  78 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  79 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
  80                                                         (same as EFER) */
  81 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  82
  83 static int w83697ug_select_wd_register(void)
  84 {
  85         unsigned char c;
  86         unsigned char version;
  87
  88         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  89         outb_p(0x87, WDT_EFER); /* Again according to manual */
  90
  91         outb(0x20, WDT_EFER);   /* check chip version   */
  92         version = inb(WDT_EFDR);
  93
  94         if (version == 0x68) {  /* W83697UG             */
  95                 pr_info("Watchdog chip version 0x%02x = W83697UG/UF found at 0x%04x\n",
  96                         version, wdt_io);
  97
  98                 outb_p(0x2b, WDT_EFER);
  99                 c = inb_p(WDT_EFDR);    /* select WDT0 */
 100                 c &= ~0x04;
 101                 outb_p(0x2b, WDT_EFER);
 102                 outb_p(c, WDT_EFDR);    /* set pin118 to WDT0 */
 103
 104         } else {
 105                 pr_err("No W83697UG/UF could be found\n");
 106                 return -ENODEV;
 107         }
 108
 109         outb_p(0x07, WDT_EFER); /* point to logical device number reg */
 110         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
 111         outb_p(0x30, WDT_EFER); /* select CR30 */
 112         c = inb_p(WDT_EFDR);
 113         outb_p(c | 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
 114
 115         return 0;
 116 }
 117
 118 static void w83697ug_unselect_wd_register(void)
 119 {
 120         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
 121 }
 122
 123 static int w83697ug_init(void)
 124 {
 125         int ret;
 126         unsigned char t;
 127
 128         ret = w83697ug_select_wd_register();
 129         if (ret != 0)
 130                 return ret;
 131
 132         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
 133         t = inb_p(WDT_EFDR);    /* read CRF6 */
 134         if (t != 0) {
 135                 pr_info("Watchdog already running. Resetting timeout to %d sec\n",
 136                         timeout);
 137                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 138         }
 139         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 140         t = inb_p(WDT_EFDR);    /* read CRF5 */
 141         t &= ~0x0C;             /* set second mode &
 142                                         disable keyboard turning off watchdog */
 143         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 144
 145         w83697ug_unselect_wd_register();
 146         return 0;
 147 }
 148
 149 static void wdt_ctrl(int timeout)
 150 {
 151         spin_lock(&io_lock);
 152
 153         if (w83697ug_select_wd_register() < 0) {
 154                 spin_unlock(&io_lock);
 155                 return;
 156         }
 157
 158         outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
 159         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
 160
 161         w83697ug_unselect_wd_register();
 162
 163         spin_unlock(&io_lock);
 164 }
 165
 166 static int wdt_ping(void)
 167 {
 168         wdt_ctrl(timeout);
 169         return 0;
 170 }
 171
 172 static int wdt_disable(void)
 173 {
 174         wdt_ctrl(0);
 175         return 0;
 176 }
 177
 178 static int wdt_set_heartbeat(int t)
 179 {
 180         if (t < 1 || t > 255)
 181                 return -EINVAL;
 182
 183         timeout = t;
 184         return 0;
 185 }
 186
 187 static ssize_t wdt_write(struct file *file, const char __user *buf,
 188                                                 size_t count, loff_t *ppos)
 189 {
 190         if (count) {
 191                 if (!nowayout) {
 192                         size_t i;
 193
 194                         expect_close = 0;
 195
 196                         for (i = 0; i != count; i++) {
 197                                 char c;
 198                                 if (get_user(c, buf + i))
 199                                         return -EFAULT;
 200                                 if (c == 'V')
 201                                         expect_close = 42;
 202                         }
 203                 }
 204                 wdt_ping();
 205         }
 206         return count;
 207 }
 208
 209 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 210 {
 211         void __user *argp = (void __user *)arg;
 212         int __user *p = argp;
 213         int new_timeout;
 214         static const struct watchdog_info ident = {
 215                 .options =              WDIOF_KEEPALIVEPING |
 216                                         WDIOF_SETTIMEOUT |
 217                                         WDIOF_MAGICCLOSE,
 218                 .firmware_version =     1,
 219                 .identity =             "W83697UG WDT",
 220         };
 221
 222         switch (cmd) {
 223         case WDIOC_GETSUPPORT:
 224                 if (copy_to_user(argp, &ident, sizeof(ident)))
 225                         return -EFAULT;
 226                 break;
 227
 228         case WDIOC_GETSTATUS:
 229         case WDIOC_GETBOOTSTATUS:
 230                 return put_user(0, p);
 231
 232         case WDIOC_SETOPTIONS:
 233         {
 234                 int options, retval = -EINVAL;
 235
 236                 if (get_user(options, p))
 237                         return -EFAULT;
 238
 239                 if (options & WDIOS_DISABLECARD) {
 240                         wdt_disable();
 241                         retval = 0;
 242                 }
 243
 244                 if (options & WDIOS_ENABLECARD) {
 245                         wdt_ping();
 246                         retval = 0;
 247                 }
 248
 249                 return retval;
 250         }
 251
 252         case WDIOC_KEEPALIVE:
 253                 wdt_ping();
 254                 break;
 255
 256         case WDIOC_SETTIMEOUT:
 257                 if (get_user(new_timeout, p))
 258                         return -EFAULT;
 259                 if (wdt_set_heartbeat(new_timeout))
 260                         return -EINVAL;
 261                 wdt_ping();
 262                 /* Fall */
 263
 264         case WDIOC_GETTIMEOUT:
 265                 return put_user(timeout, p);
 266
 267         default:
 268                 return -ENOTTY;
 269         }
 270         return 0;
 271 }
 272
 273 static int wdt_open(struct inode *inode, struct file *file)
 274 {
 275         if (test_and_set_bit(0, &wdt_is_open))
 276                 return -EBUSY;
 277         /*
 278          *      Activate
 279          */
 280
 281         wdt_ping();
 282         return nonseekable_open(inode, file);
 283 }
 284
 285 static int wdt_close(struct inode *inode, struct file *file)
 286 {
 287         if (expect_close == 42)
 288                 wdt_disable();
 289         else {
 290                 pr_crit("Unexpected close, not stopping watchdog!\n");
 291                 wdt_ping();
 292         }
 293         expect_close = 0;
 294         clear_bit(0, &wdt_is_open);
 295         return 0;
 296 }
 297
 298 /*
 299  *      Notifier for system down
 300  */
 301
 302 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 303         void *unused)
 304 {
 305         if (code == SYS_DOWN || code == SYS_HALT)
 306                 wdt_disable();  /* Turn the WDT off */
 307
 308         return NOTIFY_DONE;
 309 }
 310
 311 /*
 312  *      Kernel Interfaces
 313  */
 314
 315 static const struct file_operations wdt_fops = {
 316         .owner          = THIS_MODULE,
 317         .llseek         = no_llseek,
 318         .write          = wdt_write,
 319         .unlocked_ioctl = wdt_ioctl,
 320         .open           = wdt_open,
 321         .release        = wdt_close,
 322 };
 323
 324 static struct miscdevice wdt_miscdev = {
 325         .minor = WATCHDOG_MINOR,
 326         .name = "watchdog",
 327         .fops = &wdt_fops,
 328 };
 329
 330 /*
 331  *      The WDT needs to learn about soft shutdowns in order to
 332  *      turn the timebomb registers off.
 333  */
 334
 335 static struct notifier_block wdt_notifier = {
 336         .notifier_call = wdt_notify_sys,
 337 };
 338
 339 static int __init wdt_init(void)
 340 {
 341         int ret;
 342
 343         pr_info("WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising\n");
 344
 345         if (wdt_set_heartbeat(timeout)) {
 346                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 347                 pr_info("timeout value must be 1<=timeout<=255, using %d\n",
 348                         WATCHDOG_TIMEOUT);
 349         }
 350
 351         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 352                 pr_err("I/O address 0x%04x already in use\n", wdt_io);
 353                 ret = -EIO;
 354                 goto out;
 355         }
 356
 357         ret = w83697ug_init();
 358         if (ret != 0)
 359                 goto unreg_regions;
 360
 361         ret = register_reboot_notifier(&wdt_notifier);
 362         if (ret != 0) {
 363                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
 364                 goto unreg_regions;
 365         }
 366
 367         ret = misc_register(&wdt_miscdev);
 368         if (ret != 0) {
 369                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 370                        WATCHDOG_MINOR, ret);
 371                 goto unreg_reboot;
 372         }
 373
 374         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 375                 timeout, nowayout);
 376
 377 out:
 378         return ret;
 379 unreg_reboot:
 380         unregister_reboot_notifier(&wdt_notifier);
 381 unreg_regions:
 382         release_region(wdt_io, 1);
 383         goto out;
 384 }
 385
 386 static void __exit wdt_exit(void)
 387 {
 388         misc_deregister(&wdt_miscdev);
 389         unregister_reboot_notifier(&wdt_notifier);
 390         release_region(wdt_io, 1);
 391 }
 392
 393 module_init(wdt_init);
 394 module_exit(wdt_exit);
 395
 396 MODULE_LICENSE("GPL");
 397 MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
 398 MODULE_DESCRIPTION("w83697ug/uf WDT driver");
 399 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);