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
  37 #include <asm/io.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/system.h>
  40
  41 #define WATCHDOG_NAME "w83627hf WDT"
  42 #define PFX WATCHDOG_NAME ": "
  43 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  44
  45 static unsigned long wdt_is_open;
  46 static char expect_close;
  47
  48 /* You must set this - there is no sane way to probe for this board. */
  49 static int wdt_io = 0x2E;
  50 module_param(wdt_io, int, 0);
  51 MODULE_PARM_DESC(wdt_io, "w83627hf WDT io port (default 0x2E)");
  52
  53 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  54 module_param(timeout, int, 0);
  55 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  56
  57 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  58 static int nowayout = 1;
  59 #else
  60 static int nowayout = 0;
  61 #endif
  62
  63 module_param(nowayout, int, 0);
  64 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  65
  66 /*
  67  *      Kernel methods.
  68  */
  69
  70 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  71 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register (same as EFER) */
  72 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  73
  74 static void
  75 w83627hf_select_wd_register(void)
  76 {
  77         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  78         outb_p(0x87, WDT_EFER); /* Again according to manual */
  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 w83627hf_unselect_wd_register(void)
  88 {
  89         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
  90 }
  91
  92 /* tyan motherboards seem to set F5 to 0x4C ?
  93  * So explicitly init to appropriate value. */
  94 static void
  95 w83627hf_init(void)
  96 {
  97         unsigned char t;
  98
  99         w83627hf_select_wd_register();
 100
 101         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 102         t=inb_p(WDT_EFDR);      /* read CRF5 */
 103         t&=~0x0C;               /* set second mode & disable keyboard turning off watchdog */
 104         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 105
 106         w83627hf_unselect_wd_register();
 107 }
 108
 109 static void
 110 wdt_ctrl(int timeout)
 111 {
 112         w83627hf_select_wd_register();
 113
 114         outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
 115         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
 116
 117         w83627hf_unselect_wd_register();
 118 }
 119
 120 static int
 121 wdt_ping(void)
 122 {
 123         wdt_ctrl(timeout);
 124         return 0;
 125 }
 126
 127 static int
 128 wdt_disable(void)
 129 {
 130         wdt_ctrl(0);
 131         return 0;
 132 }
 133
 134 static int
 135 wdt_set_heartbeat(int t)
 136 {
 137         if ((t < 1) || (t > 63))
 138                 return -EINVAL;
 139
 140         timeout = t;
 141         return 0;
 142 }
 143
 144 static ssize_t
 145 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 146 {
 147         if (count) {
 148                 if (!nowayout) {
 149                         size_t i;
 150
 151                         expect_close = 0;
 152
 153                         for (i = 0; i != count; i++) {
 154                                 char c;
 155                                 if (get_user(c, buf+i))
 156                                         return -EFAULT;
 157                                 if (c == 'V')
 158                                         expect_close = 42;
 159                         }
 160                 }
 161                 wdt_ping();
 162         }
 163         return count;
 164 }
 165
 166 static int
 167 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 168           unsigned long arg)
 169 {
 170         void __user *argp = (void __user *)arg;
 171         int __user *p = argp;
 172         int new_timeout;
 173         static struct watchdog_info ident = {
 174                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 175                 .firmware_version = 1,
 176                 .identity = "W83627HF WDT",
 177         };
 178
 179         switch (cmd) {
 180         case WDIOC_GETSUPPORT:
 181           if (copy_to_user(argp, &ident, sizeof(ident)))
 182             return -EFAULT;
 183           break;
 184
 185         case WDIOC_GETSTATUS:
 186         case WDIOC_GETBOOTSTATUS:
 187           return put_user(0, p);
 188
 189         case WDIOC_KEEPALIVE:
 190           wdt_ping();
 191           break;
 192
 193         case WDIOC_SETTIMEOUT:
 194           if (get_user(new_timeout, p))
 195                   return -EFAULT;
 196           if (wdt_set_heartbeat(new_timeout))
 197                   return -EINVAL;
 198           wdt_ping();
 199           /* Fall */
 200
 201         case WDIOC_GETTIMEOUT:
 202           return put_user(timeout, p);
 203
 204         case WDIOC_SETOPTIONS:
 205         {
 206           int options, retval = -EINVAL;
 207
 208           if (get_user(options, p))
 209             return -EFAULT;
 210
 211           if (options & WDIOS_DISABLECARD) {
 212             wdt_disable();
 213             retval = 0;
 214           }
 215
 216           if (options & WDIOS_ENABLECARD) {
 217             wdt_ping();
 218             retval = 0;
 219           }
 220
 221           return retval;
 222         }
 223
 224         default:
 225           return -ENOIOCTLCMD;
 226         }
 227         return 0;
 228 }
 229
 230 static int
 231 wdt_open(struct inode *inode, struct file *file)
 232 {
 233         if (test_and_set_bit(0, &wdt_is_open))
 234                 return -EBUSY;
 235         /*
 236          *      Activate
 237          */
 238
 239         wdt_ping();
 240         return nonseekable_open(inode, file);
 241 }
 242
 243 static int
 244 wdt_close(struct inode *inode, struct file *file)
 245 {
 246         if (expect_close == 42) {
 247                 wdt_disable();
 248         } else {
 249                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 250                 wdt_ping();
 251         }
 252         expect_close = 0;
 253         clear_bit(0, &wdt_is_open);
 254         return 0;
 255 }
 256
 257 /*
 258  *      Notifier for system down
 259  */
 260
 261 static int
 262 wdt_notify_sys(struct notifier_block *this, unsigned long code,
 263         void *unused)
 264 {
 265         if (code == SYS_DOWN || code == SYS_HALT) {
 266                 /* Turn the WDT off */
 267                 wdt_disable();
 268         }
 269         return NOTIFY_DONE;
 270 }
 271
 272 /*
 273  *      Kernel Interfaces
 274  */
 275
 276 static struct file_operations wdt_fops = {
 277         .owner          = THIS_MODULE,
 278         .llseek         = no_llseek,
 279         .write          = wdt_write,
 280         .ioctl          = wdt_ioctl,
 281         .open           = wdt_open,
 282         .release        = wdt_close,
 283 };
 284
 285 static struct miscdevice wdt_miscdev = {
 286         .minor = WATCHDOG_MINOR,
 287         .name = "watchdog",
 288         .fops = &wdt_fops,
 289 };
 290
 291 /*
 292  *      The WDT needs to learn about soft shutdowns in order to
 293  *      turn the timebomb registers off.
 294  */
 295
 296 static struct notifier_block wdt_notifier = {
 297         .notifier_call = wdt_notify_sys,
 298 };
 299
 300 static int __init
 301 wdt_init(void)
 302 {
 303         int ret;
 304
 305         printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF Super I/O chip initialising.\n");
 306
 307         if (wdt_set_heartbeat(timeout)) {
 308                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 309                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=63, using %d\n",
 310                         WATCHDOG_TIMEOUT);
 311         }
 312
 313         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 314                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 315                         wdt_io);
 316                 ret = -EIO;
 317                 goto out;
 318         }
 319
 320         w83627hf_init();
 321
 322         ret = register_reboot_notifier(&wdt_notifier);
 323         if (ret != 0) {
 324                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 325                         ret);
 326                 goto unreg_regions;
 327         }
 328
 329         ret = misc_register(&wdt_miscdev);
 330         if (ret != 0) {
 331                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 332                         WATCHDOG_MINOR, ret);
 333                 goto unreg_reboot;
 334         }
 335
 336         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 337                 timeout, nowayout);
 338
 339 out:
 340         return ret;
 341 unreg_reboot:
 342         unregister_reboot_notifier(&wdt_notifier);
 343 unreg_regions:
 344         release_region(wdt_io, 1);
 345         goto out;
 346 }
 347
 348 static void __exit
 349 wdt_exit(void)
 350 {
 351         misc_deregister(&wdt_miscdev);
 352         unregister_reboot_notifier(&wdt_notifier);
 353         release_region(wdt_io,1);
 354 }
 355
 356 module_init(wdt_init);
 357 module_exit(wdt_exit);
 358
 359 MODULE_LICENSE("GPL");
 360 MODULE_AUTHOR("Pádraig Brady <P@draigBrady.com>");
 361 MODULE_DESCRIPTION("w38627hf WDT driver");
 362 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);