LXR linux/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
  49static struct platform_device *ibwdt_platform_device;
  50static unsigned long ibwdt_is_open;
  51static DEFINE_SPINLOCK(ibwdt_lock);
  52static 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
  94static 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
 119static int wd_margin = WD_TIMO;
 120
 121static int nowayout = WATCHDOG_NOWAYOUT;
 122module_param(nowayout, int, 0);
 123MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 124
 125
 126/*
 127 *      Watchdog Operations
 128 */
 129
 130static void
 131ibwdt_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
 141static void
 142ibwdt_disable(void)
 143{
 144        spin_lock(&ibwdt_lock);
 145        outb_p(0, WDT_STOP);
 146        spin_unlock(&ibwdt_lock);
 147}
 148
 149static int
 150ibwdt_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
 168static ssize_t
 169ibwdt_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
 191static int
 192ibwdt_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
 256static int
 257ibwdt_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
 270static int
 271ibwdt_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
 288static 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
 297static struct miscdevice ibwdt_miscdev = {
 298        .minor = WATCHDOG_MINOR,
 299        .name = "watchdog",
 300        .fops = &ibwdt_fops,
 301};
 302
 303/*
 304 *      Init & exit routines
 305 */
 306
 307static 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
 332out_nomisc:
 333        release_region(WDT_START, 1);
 334out_nostartreg:
 335#if WDT_START != WDT_STOP
 336        release_region(WDT_STOP, 1);
 337#endif
 338out_nostopreg:
 339        return res;
 340}
 341
 342static 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
 352static void ibwdt_shutdown(struct platform_device *dev)
 353{
 354        /* Turn the WDT off if we have a soft shutdown */
 355        ibwdt_disable();
 356}
 357
 358static 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
 368static 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
 386unreg_platform_driver:
 387        platform_driver_unregister(&ibwdt_driver);
 388        return err;
 389}
 390
 391static 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
 398module_init(ibwdt_init);
 399module_exit(ibwdt_exit);
 400
 401MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
 402MODULE_DESCRIPTION("IB700 SBC watchdog driver");
 403MODULE_LICENSE("GPL");
 404MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 405
 406/* end of ib700wdt.c */
 407