linux/drivers/watchdog/ib700wdt.c
<<
>>
Prefs
   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@lxorguk.ukuu.org.uk>,
  15 *                                              All Rights Reserved.
  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@lxorguk.ukuu.org.uk>
  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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  35
  36#include <linux/module.h>
  37#include <linux/types.h>
  38#include <linux/miscdevice.h>
  39#include <linux/watchdog.h>
  40#include <linux/ioport.h>
  41#include <linux/fs.h>
  42#include <linux/init.h>
  43#include <linux/spinlock.h>
  44#include <linux/moduleparam.h>
  45#include <linux/platform_device.h>
  46#include <linux/io.h>
  47#include <linux/uaccess.h>
  48
  49
  50static struct platform_device *ibwdt_platform_device;
  51static unsigned long ibwdt_is_open;
  52static DEFINE_SPINLOCK(ibwdt_lock);
  53static char expect_close;
  54
  55/* Module information */
  56#define DRV_NAME "ib700wdt"
  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#define WDT_STOP 0x441
  95#define WDT_START 0x443
  96
  97/* Default timeout */
  98#define WATCHDOG_TIMEOUT 30             /* 30 seconds +/- 20% */
  99static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
 100module_param(timeout, int, 0);
 101MODULE_PARM_DESC(timeout,
 102        "Watchdog timeout in seconds. 0<= timeout <=30, default="
 103                __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
 104
 105static bool nowayout = WATCHDOG_NOWAYOUT;
 106module_param(nowayout, bool, 0);
 107MODULE_PARM_DESC(nowayout,
 108                "Watchdog cannot be stopped once started (default="
 109                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 110
 111
 112/*
 113 *      Watchdog Operations
 114 */
 115
 116static void ibwdt_ping(void)
 117{
 118        int wd_margin = 15 - ((timeout + 1) / 2);
 119
 120        spin_lock(&ibwdt_lock);
 121
 122        /* Write a watchdog value */
 123        outb_p(wd_margin, WDT_START);
 124
 125        spin_unlock(&ibwdt_lock);
 126}
 127
 128static void ibwdt_disable(void)
 129{
 130        spin_lock(&ibwdt_lock);
 131        outb_p(0, WDT_STOP);
 132        spin_unlock(&ibwdt_lock);
 133}
 134
 135static int ibwdt_set_heartbeat(int t)
 136{
 137        if (t < 0 || t > 30)
 138                return -EINVAL;
 139
 140        timeout = t;
 141        return 0;
 142}
 143
 144/*
 145 *      /dev/watchdog handling
 146 */
 147
 148static ssize_t ibwdt_write(struct file *file, const char __user *buf,
 149                                                size_t count, loff_t *ppos)
 150{
 151        if (count) {
 152                if (!nowayout) {
 153                        size_t i;
 154
 155                        /* In case it was set long ago */
 156                        expect_close = 0;
 157
 158                        for (i = 0; i != count; i++) {
 159                                char c;
 160                                if (get_user(c, buf + i))
 161                                        return -EFAULT;
 162                                if (c == 'V')
 163                                        expect_close = 42;
 164                        }
 165                }
 166                ibwdt_ping();
 167        }
 168        return count;
 169}
 170
 171static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 172{
 173        int new_margin;
 174        void __user *argp = (void __user *)arg;
 175        int __user *p = argp;
 176
 177        static const struct watchdog_info ident = {
 178                .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 179                                                        | WDIOF_MAGICCLOSE,
 180                .firmware_version = 1,
 181                .identity = "IB700 WDT",
 182        };
 183
 184        switch (cmd) {
 185        case WDIOC_GETSUPPORT:
 186                if (copy_to_user(argp, &ident, sizeof(ident)))
 187                        return -EFAULT;
 188                break;
 189
 190        case WDIOC_GETSTATUS:
 191        case WDIOC_GETBOOTSTATUS:
 192                return put_user(0, p);
 193
 194        case WDIOC_SETOPTIONS:
 195        {
 196                int options, retval = -EINVAL;
 197
 198                if (get_user(options, p))
 199                        return -EFAULT;
 200
 201                if (options & WDIOS_DISABLECARD) {
 202                        ibwdt_disable();
 203                        retval = 0;
 204                }
 205                if (options & WDIOS_ENABLECARD) {
 206                        ibwdt_ping();
 207                        retval = 0;
 208                }
 209                return retval;
 210        }
 211        case WDIOC_KEEPALIVE:
 212                ibwdt_ping();
 213                break;
 214
 215        case WDIOC_SETTIMEOUT:
 216                if (get_user(new_margin, p))
 217                        return -EFAULT;
 218                if (ibwdt_set_heartbeat(new_margin))
 219                        return -EINVAL;
 220                ibwdt_ping();
 221                /* Fall */
 222
 223        case WDIOC_GETTIMEOUT:
 224                return put_user(timeout, p);
 225
 226        default:
 227                return -ENOTTY;
 228        }
 229        return 0;
 230}
 231
 232static int ibwdt_open(struct inode *inode, struct file *file)
 233{
 234        if (test_and_set_bit(0, &ibwdt_is_open))
 235                return -EBUSY;
 236        if (nowayout)
 237                __module_get(THIS_MODULE);
 238
 239        /* Activate */
 240        ibwdt_ping();
 241        return nonseekable_open(inode, file);
 242}
 243
 244static int ibwdt_close(struct inode *inode, struct file *file)
 245{
 246        if (expect_close == 42) {
 247                ibwdt_disable();
 248        } else {
 249                pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
 250                ibwdt_ping();
 251        }
 252        clear_bit(0, &ibwdt_is_open);
 253        expect_close = 0;
 254        return 0;
 255}
 256
 257/*
 258 *      Kernel Interfaces
 259 */
 260
 261static const struct file_operations ibwdt_fops = {
 262        .owner          = THIS_MODULE,
 263        .llseek         = no_llseek,
 264        .write          = ibwdt_write,
 265        .unlocked_ioctl = ibwdt_ioctl,
 266        .open           = ibwdt_open,
 267        .release        = ibwdt_close,
 268};
 269
 270static struct miscdevice ibwdt_miscdev = {
 271        .minor = WATCHDOG_MINOR,
 272        .name = "watchdog",
 273        .fops = &ibwdt_fops,
 274};
 275
 276/*
 277 *      Init & exit routines
 278 */
 279
 280static int ibwdt_probe(struct platform_device *dev)
 281{
 282        int res;
 283
 284#if WDT_START != WDT_STOP
 285        if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
 286                pr_err("STOP method I/O %X is not available\n", WDT_STOP);
 287                res = -EIO;
 288                goto out_nostopreg;
 289        }
 290#endif
 291
 292        if (!request_region(WDT_START, 1, "IB700 WDT")) {
 293                pr_err("START method I/O %X is not available\n", WDT_START);
 294                res = -EIO;
 295                goto out_nostartreg;
 296        }
 297
 298        /* Check that the heartbeat value is within it's range ;
 299         * if not reset to the default */
 300        if (ibwdt_set_heartbeat(timeout)) {
 301                ibwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 302                pr_info("timeout value must be 0<=x<=30, using %d\n", timeout);
 303        }
 304
 305        res = misc_register(&ibwdt_miscdev);
 306        if (res) {
 307                pr_err("failed to register misc device\n");
 308                goto out_nomisc;
 309        }
 310        return 0;
 311
 312out_nomisc:
 313        release_region(WDT_START, 1);
 314out_nostartreg:
 315#if WDT_START != WDT_STOP
 316        release_region(WDT_STOP, 1);
 317#endif
 318out_nostopreg:
 319        return res;
 320}
 321
 322static int ibwdt_remove(struct platform_device *dev)
 323{
 324        misc_deregister(&ibwdt_miscdev);
 325        release_region(WDT_START, 1);
 326#if WDT_START != WDT_STOP
 327        release_region(WDT_STOP, 1);
 328#endif
 329        return 0;
 330}
 331
 332static void ibwdt_shutdown(struct platform_device *dev)
 333{
 334        /* Turn the WDT off if we have a soft shutdown */
 335        ibwdt_disable();
 336}
 337
 338static struct platform_driver ibwdt_driver = {
 339        .probe          = ibwdt_probe,
 340        .remove         = ibwdt_remove,
 341        .shutdown       = ibwdt_shutdown,
 342        .driver         = {
 343                .owner  = THIS_MODULE,
 344                .name   = DRV_NAME,
 345        },
 346};
 347
 348static int __init ibwdt_init(void)
 349{
 350        int err;
 351
 352        pr_info("WDT driver for IB700 single board computer initialising\n");
 353
 354        err = platform_driver_register(&ibwdt_driver);
 355        if (err)
 356                return err;
 357
 358        ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
 359                                                                -1, NULL, 0);
 360        if (IS_ERR(ibwdt_platform_device)) {
 361                err = PTR_ERR(ibwdt_platform_device);
 362                goto unreg_platform_driver;
 363        }
 364
 365        return 0;
 366
 367unreg_platform_driver:
 368        platform_driver_unregister(&ibwdt_driver);
 369        return err;
 370}
 371
 372static void __exit ibwdt_exit(void)
 373{
 374        platform_device_unregister(ibwdt_platform_device);
 375        platform_driver_unregister(&ibwdt_driver);
 376        pr_info("Watchdog Module Unloaded\n");
 377}
 378
 379module_init(ibwdt_init);
 380module_exit(ibwdt_exit);
 381
 382MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
 383MODULE_DESCRIPTION("IB700 SBC watchdog driver");
 384MODULE_LICENSE("GPL");
 385MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 386
 387/* end of ib700wdt.c */
 388
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.