drivers/watchdog/ib700wdt.c

   1 /*
   2  *      IB700 Single Board Computer WDT driver
   3  *
   4  *      (c) Copyright 2001 Charles Howes <chowes@vsol.net>
   5  *
   6  *      Based on advantechwdt.c which is based on acquirewdt.c which
   7  *      is based on wdt.c.
   8  *
   9  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  10  *
  11  *      Based on acquirewdt.c which is based on wdt.c.
  12  *      Original copyright messages:
  13  *
  14  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  15  *                              http://www.redhat.com
  16  *
  17  *      This program is free software; you can redistribute it and/or
  18  *      modify it under the terms of the GNU General Public License
  19  *      as published by the Free Software Foundation; either version
  20  *      2 of the License, or (at your option) any later version.
  21  *
  22  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  23  *      warranty for any of this software. This material is provided
  24  *      "AS-IS" and at no charge.
  25  *
  26  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  27  *
  28  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  29  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  30  *           Added timeout module option to override default
  31  *
  32  */
  33
  34 #include <linux/module.h>
  35 #include <linux/types.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/watchdog.h>
  38 #include <linux/ioport.h>
  39 #include <linux/fs.h>
  40 #include <linux/init.h>
  41 #include <linux/spinlock.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/platform_device.h>
  44
  45 #include <asm/io.h>
  46 #include <asm/uaccess.h>
  47 #include <asm/system.h>
  48
  49 static struct platform_device *ibwdt_platform_device;
  50 static unsigned long ibwdt_is_open;
  51 static DEFINE_SPINLOCK(ibwdt_lock);
  52 static char expect_close;
  53
  54 /* Module information */
  55 #define DRV_NAME "ib700wdt"
  56 #define PFX DRV_NAME ": "
  57
  58 /*
  59  *
  60  * Watchdog Timer Configuration
  61  *
  62  * The function of the watchdog timer is to reset the system
  63  * automatically and is defined at I/O port 0443H.  To enable the
  64  * watchdog timer and allow the system to reset, write I/O port 0443H.
  65  * To disable the timer, write I/O port 0441H for the system to stop the
  66  * watchdog function.  The timer has a tolerance of 20% for its
  67  * intervals.
  68  *
  69  * The following describes how the timer should be programmed.
  70  *
  71  * Enabling Watchdog:
  72  * MOV AX,000FH (Choose the values from 0 to F)
  73  * MOV DX,0443H
  74  * OUT DX,AX
  75  *
  76  * Disabling Watchdog:
  77  * MOV AX,000FH (Any value is fine.)
  78  * MOV DX,0441H
  79  * OUT DX,AX
  80  *
  81  * Watchdog timer control table:
  82  * Level   Value  Time/sec | Level Value Time/sec
  83  *   1       F       0     |   9     7      16
  84  *   2       E       2     |   10    6      18
  85  *   3       D       4     |   11    5      20
  86  *   4       C       6     |   12    4      22
  87  *   5       B       8     |   13    3      24
  88  *   6       A       10    |   14    2      26
  89  *   7       9       12    |   15    1      28
  90  *   8       8       14    |   16    0      30
  91  *
  92  */
  93
  94 static int wd_times[] = {
  95         30,     /* 0x0 */
  96         28,     /* 0x1 */
  97         26,     /* 0x2 */
  98         24,     /* 0x3 */
  99         22,     /* 0x4 */
 100         20,     /* 0x5 */
 101         18,     /* 0x6 */
 102         16,     /* 0x7 */
 103         14,     /* 0x8 */
 104         12,     /* 0x9 */
 105         10,     /* 0xA */
 106         8,      /* 0xB */
 107         6,      /* 0xC */
 108         4,      /* 0xD */
 109         2,      /* 0xE */
 110         0,      /* 0xF */
 111 };
 112
 113 #define WDT_STOP 0x441
 114 #define WDT_START 0x443
 115
 116 /* Default timeout */
 117 #define WD_TIMO 0               /* 30 seconds +/- 20%, from table */
 118
 119 static int wd_margin = WD_TIMO;
 120
 121 static int nowayout = WATCHDOG_NOWAYOUT;
 122 module_param(nowayout, int, 0);
 123 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 124
 125
 126 /*
 127  *      Watchdog Operations
 128  */
 129
 130 static void
 131 ibwdt_ping(void)
 132 {
 133         spin_lock(&ibwdt_lock);
 134
 135         /* Write a watchdog value */
 136         outb_p(wd_margin, WDT_START);
 137
 138         spin_unlock(&ibwdt_lock);
 139 }
 140
 141 static void
 142 ibwdt_disable(void)
 143 {
 144         spin_lock(&ibwdt_lock);
 145         outb_p(0, WDT_STOP);
 146         spin_unlock(&ibwdt_lock);
 147 }
 148
 149 static int
 150 ibwdt_set_heartbeat(int t)
 151 {
 152         int i;
 153
 154         if ((t < 0) || (t > 30))
 155                 return -EINVAL;
 156
 157         for (i = 0x0F; i > -1; i--)
 158                 if (wd_times[i] > t)
 159                         break;
 160         wd_margin = i;
 161         return 0;
 162 }
 163
 164 /*
 165  *      /dev/watchdog handling
 166  */
 167
 168 static ssize_t
 169 ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 170 {
 171         if (count) {
 172                 if (!nowayout) {
 173                         size_t i;
 174
 175                         /* In case it was set long ago */
 176                         expect_close = 0;
 177
 178                         for (i = 0; i != count; i++) {
 179                                 char c;
 180                                 if (get_user(c, buf + i))
 181                                         return -EFAULT;
 182                                 if (c == 'V')
 183                                         expect_close = 42;
 184                         }
 185                 }
 186                 ibwdt_ping();
 187         }
 188         return count;
 189 }
 190
 191 static int
 192 ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 193           unsigned long arg)
 194 {
 195         int new_margin;
 196         void __user *argp = (void __user *)arg;
 197         int __user *p = argp;
 198
 199         static struct watchdog_info ident = {
 200                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 201                 .firmware_version = 1,
 202                 .identity = "IB700 WDT",
 203         };
 204
 205         switch (cmd) {
 206         case WDIOC_GETSUPPORT:
 207           if (copy_to_user(argp, &ident, sizeof(ident)))
 208             return -EFAULT;
 209           break;
 210
 211         case WDIOC_GETSTATUS:
 212         case WDIOC_GETBOOTSTATUS:
 213           return put_user(0, p);
 214
 215         case WDIOC_KEEPALIVE:
 216           ibwdt_ping();
 217           break;
 218
 219         case WDIOC_SETTIMEOUT:
 220           if (get_user(new_margin, p))
 221                   return -EFAULT;
 222           if (ibwdt_set_heartbeat(new_margin))
 223                   return -EINVAL;
 224           ibwdt_ping();
 225           /* Fall */
 226
 227         case WDIOC_GETTIMEOUT:
 228           return put_user(wd_times[wd_margin], p);
 229
 230         case WDIOC_SETOPTIONS:
 231         {
 232           int options, retval = -EINVAL;
 233
 234           if (get_user(options, p))
 235             return -EFAULT;
 236
 237           if (options & WDIOS_DISABLECARD) {
 238             ibwdt_disable();
 239             retval = 0;
 240           }
 241
 242           if (options & WDIOS_ENABLECARD) {
 243             ibwdt_ping();
 244             retval = 0;
 245           }
 246
 247           return retval;
 248         }
 249
 250         default:
 251           return -ENOTTY;
 252         }
 253         return 0;
 254 }
 255
 256 static int
 257 ibwdt_open(struct inode *inode, struct file *file)
 258 {
 259         if (test_and_set_bit(0, &ibwdt_is_open)) {
 260                 return -EBUSY;
 261         }
 262         if (nowayout)
 263                 __module_get(THIS_MODULE);
 264
 265         /* Activate */
 266         ibwdt_ping();
 267         return nonseekable_open(inode, file);
 268 }
 269
 270 static int
 271 ibwdt_close(struct inode *inode, struct file *file)
 272 {
 273         if (expect_close == 42) {
 274                 ibwdt_disable();
 275         } else {
 276                 printk(KERN_CRIT PFX "WDT device closed unexpectedly.  WDT will not stop!\n");
 277                 ibwdt_ping();
 278         }
 279         clear_bit(0, &ibwdt_is_open);
 280         expect_close = 0;
 281         return 0;
 282 }
 283
 284 /*
 285  *      Kernel Interfaces
 286  */
 287
 288 static const struct file_operations ibwdt_fops = {
 289         .owner          = THIS_MODULE,
 290         .llseek         = no_llseek,
 291         .write          = ibwdt_write,
 292         .ioctl          = ibwdt_ioctl,
 293         .open           = ibwdt_open,
 294         .release        = ibwdt_close,
 295 };
 296
 297 static struct miscdevice ibwdt_miscdev = {
 298         .minor = WATCHDOG_MINOR,
 299         .name = "watchdog",
 300         .fops = &ibwdt_fops,
 301 };
 302
 303 /*
 304  *      Init & exit routines
 305  */
 306
 307 static int __devinit ibwdt_probe(struct platform_device *dev)
 308 {
 309         int res;
 310
 311 #if WDT_START != WDT_STOP
 312         if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
 313                 printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP);
 314                 res = -EIO;
 315                 goto out_nostopreg;
 316         }
 317 #endif
 318
 319         if (!request_region(WDT_START, 1, "IB700 WDT")) {
 320                 printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START);
 321                 res = -EIO;
 322                 goto out_nostartreg;
 323         }
 324
 325         res = misc_register(&ibwdt_miscdev);
 326         if (res) {
 327                 printk (KERN_ERR PFX "failed to register misc device\n");
 328                 goto out_nomisc;
 329         }
 330         return 0;
 331
 332 out_nomisc:
 333         release_region(WDT_START, 1);
 334 out_nostartreg:
 335 #if WDT_START != WDT_STOP
 336         release_region(WDT_STOP, 1);
 337 #endif
 338 out_nostopreg:
 339         return res;
 340 }
 341
 342 static int __devexit ibwdt_remove(struct platform_device *dev)
 343 {
 344         misc_deregister(&ibwdt_miscdev);
 345         release_region(WDT_START,1);
 346 #if WDT_START != WDT_STOP
 347         release_region(WDT_STOP,1);
 348 #endif
 349         return 0;
 350 }
 351
 352 static void ibwdt_shutdown(struct platform_device *dev)
 353 {
 354         /* Turn the WDT off if we have a soft shutdown */
 355         ibwdt_disable();
 356 }
 357
 358 static struct platform_driver ibwdt_driver = {
 359         .probe          = ibwdt_probe,
 360         .remove         = __devexit_p(ibwdt_remove),
 361         .shutdown       = ibwdt_shutdown,
 362         .driver         = {
 363                 .owner  = THIS_MODULE,
 364                 .name   = DRV_NAME,
 365         },
 366 };
 367
 368 static int __init ibwdt_init(void)
 369 {
 370         int err;
 371
 372         printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
 373
 374         err = platform_driver_register(&ibwdt_driver);
 375         if (err)
 376                 return err;
 377
 378         ibwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
 379         if (IS_ERR(ibwdt_platform_device)) {
 380                 err = PTR_ERR(ibwdt_platform_device);
 381                 goto unreg_platform_driver;
 382         }
 383
 384         return 0;
 385
 386 unreg_platform_driver:
 387         platform_driver_unregister(&ibwdt_driver);
 388         return err;
 389 }
 390
 391 static void __exit ibwdt_exit(void)
 392 {
 393         platform_device_unregister(ibwdt_platform_device);
 394         platform_driver_unregister(&ibwdt_driver);
 395         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 396 }
 397
 398 module_init(ibwdt_init);
 399 module_exit(ibwdt_exit);
 400
 401 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
 402 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
 403 MODULE_LICENSE("GPL");
 404 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 405
 406 /* end of ib700wdt.c */