drivers/char/watchdog/w83697hf_wdt.c

   1 /*
   2  *      w83697hf WDT driver
   3  *
   4  *      (c) Copyright 2006 Marcus Junker <junker@anduras.de>
   5  *
   6  *      Based on w83627hf_wdt.c advantechwdt.c which is based on wdt.c.
   7  *      Original copyright messages:
   8  *
   9  *     (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  10  *
  11  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  12  *
  13  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  14  *                              http://www.redhat.com
  15  *
  16  *      This program is free software; you can redistribute it and/or
  17  *      modify it under the terms of the GNU General Public License
  18  *      as published by the Free Software Foundation; either version
  19  *      2 of the License, or (at your option) any later version.
  20  *
  21  *      Neither Marcus Junker nor ANDURAS AG admit liability nor provide
  22  *      warranty for any of this software. This material is provided
  23  *      "AS-IS" and at no charge.
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/types.h>
  29 #include <linux/miscdevice.h>
  30 #include <linux/watchdog.h>
  31 #include <linux/fs.h>
  32 #include <linux/ioport.h>
  33 #include <linux/notifier.h>
  34 #include <linux/reboot.h>
  35 #include <linux/init.h>
  36 #include <linux/spinlock.h>
  37
  38 #include <asm/io.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/system.h>
  41
  42 #define WATCHDOG_NAME "w83697hf WDT"
  43 #define PFX WATCHDOG_NAME ": "
  44 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  45
  46 static unsigned long wdt_is_open;
  47 static char expect_close;
  48 static spinlock_t io_lock;
  49
  50 /* You must set this - there is no sane way to probe for this board. */
  51 static int wdt_io = 0x2E;
  52 module_param(wdt_io, int, 0);
  53 MODULE_PARM_DESC(wdt_io, "w83697hf WDT io port (default 0x2E)");
  54
  55 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  56 module_param(timeout, int, 0);
  57 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  58
  59 static int nowayout = WATCHDOG_NOWAYOUT;
  60 module_param(nowayout, int, 0);
  61 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  62
  63 /*
  64  *      Kernel methods.
  65  */
  66
  67 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  68 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register (same as EFER) */
  69 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  70
  71 static void
  72 w83697hf_select_wd_register(void)
  73 {
  74         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  75         outb_p(0x87, WDT_EFER); /* Again according to manual */
  76
  77         outb_p(0x29, WDT_EFER); /* select CR29 */
  78         outb_p(0x20, WDT_EFDR); /* select WDTO */
  79
  80         outb_p(0x07, WDT_EFER); /* point to logical device number reg */
  81         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
  82         outb_p(0x30, WDT_EFER); /* select CR30 */
  83         outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
  84 }
  85
  86 static void
  87 w83697hf_unselect_wd_register(void)
  88 {
  89         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
  90 }
  91
  92 static void
  93 w83697hf_init(void)
  94 {
  95         unsigned char t;
  96
  97         w83697hf_select_wd_register();
  98
  99         outb_p(0xF3, WDT_EFER); /* Select CRF3 */
 100
 101         t=inb_p(WDT_EFDR);      /* read CRF3 */
 102         if (t != 0) {
 103                 printk (KERN_INFO PFX "Watchdog already running. Resetting timeout to %d sec\n", timeout);
 104                 outb_p(timeout, WDT_EFDR);      /* Write back to CRF3 */
 105         }
 106         outb_p(0xF4, WDT_EFER); /* Select CRF4 */
 107         t=inb_p(WDT_EFDR);      /* read CRF4 */
 108         t&=~0x0C;               /* set second mode & disable keyboard turning off watchdog */
 109         outb_p(t, WDT_EFDR);    /* Write back to CRF4 */
 110
 111         w83697hf_unselect_wd_register();
 112 }
 113
 114 static void
 115 wdt_ctrl(int timeout)
 116 {
 117         spin_lock(&io_lock);
 118
 119         w83697hf_select_wd_register();
 120
 121         outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
 122         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
 123
 124         w83697hf_unselect_wd_register();
 125
 126         spin_unlock(&io_lock);
 127 }
 128
 129 static int
 130 wdt_ping(void)
 131 {
 132         wdt_ctrl(timeout);
 133         return 0;
 134 }
 135
 136 static int
 137 wdt_disable(void)
 138 {
 139         wdt_ctrl(0);
 140         return 0;
 141 }
 142
 143 static int
 144 wdt_set_heartbeat(int t)
 145 {
 146         if ((t < 1) || (t > 63))
 147                 return -EINVAL;
 148
 149         timeout = t;
 150         return 0;
 151 }
 152
 153 static ssize_t
 154 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 155 {
 156         if (count) {
 157                 if (!nowayout) {
 158                         size_t i;
 159
 160                         expect_close = 0;
 161
 162                         for (i = 0; i != count; i++) {
 163                                 char c;
 164                                 if (get_user(c, buf+i))
 165                                         return -EFAULT;
 166                                 if (c == 'V')
 167                                         expect_close = 42;
 168                         }
 169                 }
 170                 wdt_ping();
 171         }
 172         return count;
 173 }
 174
 175 static int
 176 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 177           unsigned long arg)
 178 {
 179         void __user *argp = (void __user *)arg;
 180         int __user *p = argp;
 181         int new_timeout;
 182         static struct watchdog_info ident = {
 183                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 184                 .firmware_version = 1,
 185                 .identity = "W83697HF WDT",
 186         };
 187
 188         switch (cmd) {
 189         case WDIOC_GETSUPPORT:
 190           if (copy_to_user(argp, &ident, sizeof(ident)))
 191             return -EFAULT;
 192           break;
 193
 194         case WDIOC_GETSTATUS:
 195         case WDIOC_GETBOOTSTATUS:
 196           return put_user(0, p);
 197
 198         case WDIOC_KEEPALIVE:
 199           wdt_ping();
 200           break;
 201
 202         case WDIOC_SETTIMEOUT:
 203           if (get_user(new_timeout, p))
 204                   return -EFAULT;
 205           if (wdt_set_heartbeat(new_timeout))
 206                   return -EINVAL;
 207           wdt_ping();
 208           /* Fall */
 209
 210         case WDIOC_GETTIMEOUT:
 211           return put_user(timeout, p);
 212
 213         case WDIOC_SETOPTIONS:
 214         {
 215           int options, retval = -EINVAL;
 216
 217           if (get_user(options, p))
 218             return -EFAULT;
 219
 220           if (options & WDIOS_DISABLECARD) {
 221             wdt_disable();
 222             retval = 0;
 223           }
 224
 225           if (options & WDIOS_ENABLECARD) {
 226             wdt_ping();
 227             retval = 0;
 228           }
 229
 230           return retval;
 231         }
 232
 233         default:
 234           return -ENOTTY;
 235         }
 236         return 0;
 237 }
 238
 239 static int
 240 wdt_open(struct inode *inode, struct file *file)
 241 {
 242         if (test_and_set_bit(0, &wdt_is_open))
 243                 return -EBUSY;
 244         /*
 245          *      Activate
 246          */
 247
 248         wdt_ping();
 249         return nonseekable_open(inode, file);
 250 }
 251
 252 static int
 253 wdt_close(struct inode *inode, struct file *file)
 254 {
 255         if (expect_close == 42) {
 256                 wdt_disable();
 257         } else {
 258                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 259                 wdt_ping();
 260         }
 261         expect_close = 0;
 262         clear_bit(0, &wdt_is_open);
 263         return 0;
 264 }
 265
 266 /*
 267  *      Notifier for system down
 268  */
 269
 270 static int
 271 wdt_notify_sys(struct notifier_block *this, unsigned long code,
 272         void *unused)
 273 {
 274         if (code == SYS_DOWN || code == SYS_HALT) {
 275                 /* Turn the WDT off */
 276                 wdt_disable();
 277         }
 278         return NOTIFY_DONE;
 279 }
 280
 281 /*
 282  *      Kernel Interfaces
 283  */
 284
 285 static struct file_operations wdt_fops = {
 286         .owner          = THIS_MODULE,
 287         .llseek         = no_llseek,
 288         .write          = wdt_write,
 289         .ioctl          = wdt_ioctl,
 290         .open           = wdt_open,
 291         .release        = wdt_close,
 292 };
 293
 294 static struct miscdevice wdt_miscdev = {
 295         .minor = WATCHDOG_MINOR,
 296         .name = "watchdog",
 297         .fops = &wdt_fops,
 298 };
 299
 300 /*
 301  *      The WDT needs to learn about soft shutdowns in order to
 302  *      turn the timebomb registers off.
 303  */
 304
 305 static struct notifier_block wdt_notifier = {
 306         .notifier_call = wdt_notify_sys,
 307 };
 308
 309 static int __init
 310 wdt_init(void)
 311 {
 312         int ret;
 313
 314         spin_lock_init(&io_lock);
 315
 316         printk(KERN_INFO "WDT driver for the Winbond(TM) W83697HF Super I/O chip initialising.\n");
 317
 318         if (wdt_set_heartbeat(timeout)) {
 319                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 320                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=63, using %d\n",
 321                         WATCHDOG_TIMEOUT);
 322         }
 323
 324         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
 325                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 326                         wdt_io);
 327                 ret = -EIO;
 328                 goto out;
 329         }
 330
 331         w83697hf_init();
 332
 333         ret = register_reboot_notifier(&wdt_notifier);
 334         if (ret != 0) {
 335                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 336                         ret);
 337                 goto unreg_regions;
 338         }
 339
 340         ret = misc_register(&wdt_miscdev);
 341         if (ret != 0) {
 342                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 343                         WATCHDOG_MINOR, ret);
 344                 goto unreg_reboot;
 345         }
 346
 347         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 348                 timeout, nowayout);
 349
 350 out:
 351         return ret;
 352 unreg_reboot:
 353         unregister_reboot_notifier(&wdt_notifier);
 354 unreg_regions:
 355         release_region(wdt_io, 2);
 356         goto out;
 357 }
 358
 359 static void __exit
 360 wdt_exit(void)
 361 {
 362         misc_deregister(&wdt_miscdev);
 363         unregister_reboot_notifier(&wdt_notifier);
 364         release_region(wdt_io, 2);
 365 }
 366
 367 module_init(wdt_init);
 368 module_exit(wdt_exit);
 369
 370 MODULE_LICENSE("GPL");
 371 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
 372 MODULE_DESCRIPTION("w83697hf WDT driver");
 373 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);