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 #include <linux/io.h>
  45 #include <linux/uaccess.h>
  46
  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,
 124                 "Watchdog cannot be stopped once started (default="
 125                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 126
 127
 128 /*
 129  *      Watchdog Operations
 130  */
 131
 132 static void
 133 ibwdt_ping(void)
 134 {
 135         spin_lock(&ibwdt_lock);
 136
 137         /* Write a watchdog value */
 138         outb_p(wd_margin, WDT_START);
 139
 140         spin_unlock(&ibwdt_lock);
 141 }
 142
 143 static void
 144 ibwdt_disable(void)
 145 {
 146         spin_lock(&ibwdt_lock);
 147         outb_p(0, WDT_STOP);
 148         spin_unlock(&ibwdt_lock);
 149 }
 150
 151 static int
 152 ibwdt_set_heartbeat(int t)
 153 {
 154         int i;
 155
 156         if ((t < 0) || (t > 30))
 157                 return -EINVAL;
 158
 159         for (i = 0x0F; i > -1; i--)
 160                 if (wd_times[i] > t)
 161                         break;
 162         wd_margin = i;
 163         return 0;
 164 }
 165
 166 /*
 167  *      /dev/watchdog handling
 168  */
 169
 170 static ssize_t ibwdt_write(struct file *file, const char __user *buf,
 171                                                 size_t count, loff_t *ppos)
 172 {
 173         if (count) {
 174                 if (!nowayout) {
 175                         size_t i;
 176
 177                         /* In case it was set long ago */
 178                         expect_close = 0;
 179
 180                         for (i = 0; i != count; i++) {
 181                                 char c;
 182                                 if (get_user(c, buf + i))
 183                                         return -EFAULT;
 184                                 if (c == 'V')
 185                                         expect_close = 42;
 186                         }
 187                 }
 188                 ibwdt_ping();
 189         }
 190         return count;
 191 }
 192
 193 static long ibwdt_ioctl(struct file *file, unsigned int cmd, 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
 201                                                         | WDIOF_MAGICCLOSE,
 202                 .firmware_version = 1,
 203                 .identity = "IB700 WDT",
 204         };
 205
 206         switch (cmd) {
 207         case WDIOC_GETSUPPORT:
 208                 if (copy_to_user(argp, &ident, sizeof(ident)))
 209                         return -EFAULT;
 210                 break;
 211
 212         case WDIOC_GETSTATUS:
 213         case WDIOC_GETBOOTSTATUS:
 214                 return put_user(0, p);
 215
 216         case WDIOC_KEEPALIVE:
 217                 ibwdt_ping();
 218                 break;
 219
 220         case WDIOC_SETTIMEOUT:
 221                 if (get_user(new_margin, p))
 222                         return -EFAULT;
 223                 if (ibwdt_set_heartbeat(new_margin))
 224                         return -EINVAL;
 225                 ibwdt_ping();
 226                 /* Fall */
 227
 228         case WDIOC_GETTIMEOUT:
 229                 return put_user(wd_times[wd_margin], 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                         ibwdt_disable();
 240                         retval = 0;
 241                 }
 242                 if (options & WDIOS_ENABLECARD) {
 243                         ibwdt_ping();
 244                         retval = 0;
 245                 }
 246                 return retval;
 247         }
 248         default:
 249                 return -ENOTTY;
 250         }
 251         return 0;
 252 }
 253
 254 static int ibwdt_open(struct inode *inode, struct file *file)
 255 {
 256         if (test_and_set_bit(0, &ibwdt_is_open))
 257                 return -EBUSY;
 258         if (nowayout)
 259                 __module_get(THIS_MODULE);
 260
 261         /* Activate */
 262         ibwdt_ping();
 263         return nonseekable_open(inode, file);
 264 }
 265
 266 static int
 267 ibwdt_close(struct inode *inode, struct file *file)
 268 {
 269         if (expect_close == 42) {
 270                 ibwdt_disable();
 271         } else {
 272                 printk(KERN_CRIT PFX
 273                      "WDT device closed unexpectedly.  WDT will not stop!\n");
 274                 ibwdt_ping();
 275         }
 276         clear_bit(0, &ibwdt_is_open);
 277         expect_close = 0;
 278         return 0;
 279 }
 280
 281 /*
 282  *      Kernel Interfaces
 283  */
 284
 285 static const struct file_operations ibwdt_fops = {
 286         .owner          = THIS_MODULE,
 287         .llseek         = no_llseek,
 288         .write          = ibwdt_write,
 289         .unlocked_ioctl = ibwdt_ioctl,
 290         .open           = ibwdt_open,
 291         .release        = ibwdt_close,
 292 };
 293
 294 static struct miscdevice ibwdt_miscdev = {
 295         .minor = WATCHDOG_MINOR,
 296         .name = "watchdog",
 297         .fops = &ibwdt_fops,
 298 };
 299
 300 /*
 301  *      Init & exit routines
 302  */
 303
 304 static int __devinit ibwdt_probe(struct platform_device *dev)
 305 {
 306         int res;
 307
 308 #if WDT_START != WDT_STOP
 309         if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
 310                 printk(KERN_ERR PFX "STOP method I/O %X is not available.\n",
 311                                                                 WDT_STOP);
 312                 res = -EIO;
 313                 goto out_nostopreg;
 314         }
 315 #endif
 316
 317         if (!request_region(WDT_START, 1, "IB700 WDT")) {
 318                 printk(KERN_ERR PFX "START method I/O %X is not available.\n",
 319                                                                 WDT_START);
 320                 res = -EIO;
 321                 goto out_nostartreg;
 322         }
 323
 324         res = misc_register(&ibwdt_miscdev);
 325         if (res) {
 326                 printk(KERN_ERR PFX "failed to register misc device\n");
 327                 goto out_nomisc;
 328         }
 329         return 0;
 330
 331 out_nomisc:
 332         release_region(WDT_START, 1);
 333 out_nostartreg:
 334 #if WDT_START != WDT_STOP
 335         release_region(WDT_STOP, 1);
 336 #endif
 337 out_nostopreg:
 338         return res;
 339 }
 340
 341 static int __devexit ibwdt_remove(struct platform_device *dev)
 342 {
 343         misc_deregister(&ibwdt_miscdev);
 344         release_region(WDT_START, 1);
 345 #if WDT_START != WDT_STOP
 346         release_region(WDT_STOP, 1);
 347 #endif
 348         return 0;
 349 }
 350
 351 static void ibwdt_shutdown(struct platform_device *dev)
 352 {
 353         /* Turn the WDT off if we have a soft shutdown */
 354         ibwdt_disable();
 355 }
 356
 357 static struct platform_driver ibwdt_driver = {
 358         .probe          = ibwdt_probe,
 359         .remove         = __devexit_p(ibwdt_remove),
 360         .shutdown       = ibwdt_shutdown,
 361         .driver         = {
 362                 .owner  = THIS_MODULE,
 363                 .name   = DRV_NAME,
 364         },
 365 };
 366
 367 static int __init ibwdt_init(void)
 368 {
 369         int err;
 370
 371         printk(KERN_INFO PFX
 372                 "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,
 379                                                                 -1, NULL, 0);
 380         if (IS_ERR(ibwdt_platform_device)) {
 381                 err = PTR_ERR(ibwdt_platform_device);
 382                 goto unreg_platform_driver;
 383         }
 384
 385         return 0;
 386
 387 unreg_platform_driver:
 388         platform_driver_unregister(&ibwdt_driver);
 389         return err;
 390 }
 391
 392 static void __exit ibwdt_exit(void)
 393 {
 394         platform_device_unregister(ibwdt_platform_device);
 395         platform_driver_unregister(&ibwdt_driver);
 396         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 397 }
 398
 399 module_init(ibwdt_init);
 400 module_exit(ibwdt_exit);
 401
 402 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
 403 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
 404 MODULE_LICENSE("GPL");
 405 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 406
 407 /* end of ib700wdt.c */