drivers/char/watchdog/w83627hf_wdt.c

   1 /*
   2  *      w83627hf WDT driver
   3  *
   4  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
   5  *
   6  *      Based on advantechwdt.c which is based on wdt.c.
   7  *      Original copyright messages:
   8  *
   9  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  10  *
  11  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  12  *                              http://www.redhat.com
  13  *
  14  *      This program is free software; you can redistribute it and/or
  15  *      modify it under the terms of the GNU General Public License
  16  *      as published by the Free Software Foundation; either version
  17  *      2 of the License, or (at your option) any later version.
  18  *
  19  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  20  *      warranty for any of this software. This material is provided
  21  *      "AS-IS" and at no charge.
  22  *
  23  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  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 "w83627hf 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, "w83627hf 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 w83627hf_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(0x07, WDT_EFER); /* point to logical device number reg */
  78         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
  79         outb_p(0x30, WDT_EFER); /* select CR30 */
  80         outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
  81 }
  82
  83 static void
  84 w83627hf_unselect_wd_register(void)
  85 {
  86         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
  87 }
  88
  89 /* tyan motherboards seem to set F5 to 0x4C ?
  90  * So explicitly init to appropriate value. */
  91 static void
  92 w83627hf_init(void)
  93 {
  94         unsigned char t;
  95
  96         w83627hf_select_wd_register();
  97
  98         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
  99         t=inb_p(WDT_EFDR);      /* read CRF6 */
 100         if (t != 0) {
 101                 printk (KERN_INFO PFX "Watchdog already running. Resetting timeout to %d sec\n", timeout);
 102                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 103         }
 104         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 105         t=inb_p(WDT_EFDR);      /* read CRF5 */
 106         t&=~0x0C;               /* set second mode & disable keyboard turning off watchdog */
 107         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 108
 109         w83627hf_unselect_wd_register();
 110 }
 111
 112 static void
 113 wdt_ctrl(int timeout)
 114 {
 115         spin_lock(&io_lock);
 116
 117         w83627hf_select_wd_register();
 118
 119         outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
 120         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
 121
 122         w83627hf_unselect_wd_register();
 123
 124         spin_unlock(&io_lock);
 125 }
 126
 127 static int
 128 wdt_ping(void)
 129 {
 130         wdt_ctrl(timeout);
 131         return 0;
 132 }
 133
 134 static int
 135 wdt_disable(void)
 136 {
 137         wdt_ctrl(0);
 138         return 0;
 139 }
 140
 141 static int
 142 wdt_set_heartbeat(int t)
 143 {
 144         if ((t < 1) || (t > 63))
 145                 return -EINVAL;
 146
 147         timeout = t;
 148         return 0;
 149 }
 150
 151 static ssize_t
 152 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 153 {
 154         if (count) {
 155                 if (!nowayout) {
 156                         size_t i;
 157
 158                         expect_close = 0;
 159
 160                         for (i = 0; i != count; i++) {
 161                                 char c;
 162                                 if (get_user(c, buf+i))
 163                                         return -EFAULT;
 164                                 if (c == 'V')
 165                                         expect_close = 42;
 166                         }
 167                 }
 168                 wdt_ping();
 169         }
 170         return count;
 171 }
 172
 173 static int
 174 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 175           unsigned long arg)
 176 {
 177         void __user *argp = (void __user *)arg;
 178         int __user *p = argp;
 179         int new_timeout;
 180         static struct watchdog_info ident = {
 181                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 182                 .firmware_version = 1,
 183                 .identity = "W83627HF WDT",
 184         };
 185
 186         switch (cmd) {
 187         case WDIOC_GETSUPPORT:
 188           if (copy_to_user(argp, &ident, sizeof(ident)))
 189             return -EFAULT;
 190           break;
 191
 192         case WDIOC_GETSTATUS:
 193         case WDIOC_GETBOOTSTATUS:
 194           return put_user(0, p);
 195
 196         case WDIOC_KEEPALIVE:
 197           wdt_ping();
 198           break;
 199
 200         case WDIOC_SETTIMEOUT:
 201           if (get_user(new_timeout, p))
 202                   return -EFAULT;
 203           if (wdt_set_heartbeat(new_timeout))
 204                   return -EINVAL;
 205           wdt_ping();
 206           /* Fall */
 207
 208         case WDIOC_GETTIMEOUT:
 209           return put_user(timeout, p);
 210
 211         case WDIOC_SETOPTIONS:
 212         {
 213           int options, retval = -EINVAL;
 214
 215           if (get_user(options, p))
 216             return -EFAULT;
 217
 218           if (options & WDIOS_DISABLECARD) {
 219             wdt_disable();
 220             retval = 0;
 221           }
 222
 223           if (options & WDIOS_ENABLECARD) {
 224             wdt_ping();
 225             retval = 0;
 226           }
 227
 228           return retval;
 229         }
 230
 231         default:
 232           return -ENOTTY;
 233         }
 234         return 0;
 235 }
 236
 237 static int
 238 wdt_open(struct inode *inode, struct file *file)
 239 {
 240         if (test_and_set_bit(0, &wdt_is_open))
 241                 return -EBUSY;
 242         /*
 243          *      Activate
 244          */
 245
 246         wdt_ping();
 247         return nonseekable_open(inode, file);
 248 }
 249
 250 static int
 251 wdt_close(struct inode *inode, struct file *file)
 252 {
 253         if (expect_close == 42) {
 254                 wdt_disable();
 255         } else {
 256                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 257                 wdt_ping();
 258         }
 259         expect_close = 0;
 260         clear_bit(0, &wdt_is_open);
 261         return 0;
 262 }
 263
 264 /*
 265  *      Notifier for system down
 266  */
 267
 268 static int
 269 wdt_notify_sys(struct notifier_block *this, unsigned long code,
 270         void *unused)
 271 {
 272         if (code == SYS_DOWN || code == SYS_HALT) {
 273                 /* Turn the WDT off */
 274                 wdt_disable();
 275         }
 276         return NOTIFY_DONE;
 277 }
 278
 279 /*
 280  *      Kernel Interfaces
 281  */
 282
 283 static const struct file_operations wdt_fops = {
 284         .owner          = THIS_MODULE,
 285         .llseek         = no_llseek,
 286         .write          = wdt_write,
 287         .ioctl          = wdt_ioctl,
 288         .open           = wdt_open,
 289         .release        = wdt_close,
 290 };
 291
 292 static struct miscdevice wdt_miscdev = {
 293         .minor = WATCHDOG_MINOR,
 294         .name = "watchdog",
 295         .fops = &wdt_fops,
 296 };
 297
 298 /*
 299  *      The WDT needs to learn about soft shutdowns in order to
 300  *      turn the timebomb registers off.
 301  */
 302
 303 static struct notifier_block wdt_notifier = {
 304         .notifier_call = wdt_notify_sys,
 305 };
 306
 307 static int __init
 308 wdt_init(void)
 309 {
 310         int ret;
 311
 312         spin_lock_init(&io_lock);
 313
 314         printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF Super I/O chip initialising.\n");
 315
 316         if (wdt_set_heartbeat(timeout)) {
 317                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 318                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=63, using %d\n",
 319                         WATCHDOG_TIMEOUT);
 320         }
 321
 322         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 323                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 324                         wdt_io);
 325                 ret = -EIO;
 326                 goto out;
 327         }
 328
 329         w83627hf_init();
 330
 331         ret = register_reboot_notifier(&wdt_notifier);
 332         if (ret != 0) {
 333                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 334                         ret);
 335                 goto unreg_regions;
 336         }
 337
 338         ret = misc_register(&wdt_miscdev);
 339         if (ret != 0) {
 340                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 341                         WATCHDOG_MINOR, ret);
 342                 goto unreg_reboot;
 343         }
 344
 345         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 346                 timeout, nowayout);
 347
 348 out:
 349         return ret;
 350 unreg_reboot:
 351         unregister_reboot_notifier(&wdt_notifier);
 352 unreg_regions:
 353         release_region(wdt_io, 1);
 354         goto out;
 355 }
 356
 357 static void __exit
 358 wdt_exit(void)
 359 {
 360         misc_deregister(&wdt_miscdev);
 361         unregister_reboot_notifier(&wdt_notifier);
 362         release_region(wdt_io,1);
 363 }
 364
 365 module_init(wdt_init);
 366 module_exit(wdt_exit);
 367
 368 MODULE_LICENSE("GPL");
 369 MODULE_AUTHOR("Pádraig Brady <P@draigBrady.com>");
 370 MODULE_DESCRIPTION("w83627hf WDT driver");
 371 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);