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