linux/drivers/watchdog/advantechwdt.c
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   1/*
   2 *      Advantech Single Board Computer WDT driver
   3 *
   4 *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
   5 *
   6 *      Based on acquirewdt.c which is based on wdt.c.
   7 *      Original copyright messages:
   8 *
   9 *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  10 *                                              All Rights Reserved.
  11 *
  12 *      This program is free software; you can redistribute it and/or
  13 *      modify it under the terms of the GNU General Public License
  14 *      as published by the Free Software Foundation; either version
  15 *      2 of the License, or (at your option) any later version.
  16 *
  17 *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  18 *      warranty for any of this software. This material is provided
  19 *      "AS-IS" and at no charge.
  20 *
  21 *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
  22 *
  23 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  24 *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  25 *
  26 *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
  27 *          Clean up ioctls, clean up init + exit, add expect close support,
  28 *          add wdt_start and wdt_stop as parameters.
  29 */
  30
  31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  32
  33#include <linux/module.h>
  34#include <linux/moduleparam.h>
  35#include <linux/types.h>
  36#include <linux/miscdevice.h>
  37#include <linux/watchdog.h>
  38#include <linux/fs.h>
  39#include <linux/ioport.h>
  40#include <linux/platform_device.h>
  41#include <linux/init.h>
  42#include <linux/io.h>
  43#include <linux/uaccess.h>
  44
  45
  46#define DRV_NAME "advantechwdt"
  47#define WATCHDOG_NAME "Advantech WDT"
  48#define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  49
  50/* the watchdog platform device */
  51static struct platform_device *advwdt_platform_device;
  52static unsigned long advwdt_is_open;
  53static char adv_expect_close;
  54
  55/*
  56 *      You must set these - there is no sane way to probe for this board.
  57 *
  58 *      To enable or restart, write the timeout value in seconds (1 to 63)
  59 *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  60 *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  61 *      check your manual (at least the PCA-6159 seems to be different -
  62 *      the manual says wdt_stop is 0x43, not 0x443).
  63 *      (0x43 is also a write-only control register for the 8254 timer!)
  64 */
  65
  66static int wdt_stop = 0x443;
  67module_param(wdt_stop, int, 0);
  68MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  69
  70static int wdt_start = 0x443;
  71module_param(wdt_start, int, 0);
  72MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  73
  74static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  75module_param(timeout, int, 0);
  76MODULE_PARM_DESC(timeout,
  77        "Watchdog timeout in seconds. 1<= timeout <=63, default="
  78                __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  79
  80static bool nowayout = WATCHDOG_NOWAYOUT;
  81module_param(nowayout, bool, 0);
  82MODULE_PARM_DESC(nowayout,
  83        "Watchdog cannot be stopped once started (default="
  84                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  85
  86/*
  87 *      Watchdog Operations
  88 */
  89
  90static void advwdt_ping(void)
  91{
  92        /* Write a watchdog value */
  93        outb_p(timeout, wdt_start);
  94}
  95
  96static void advwdt_disable(void)
  97{
  98        inb_p(wdt_stop);
  99}
 100
 101static int advwdt_set_heartbeat(int t)
 102{
 103        if (t < 1 || t > 63)
 104                return -EINVAL;
 105        timeout = t;
 106        return 0;
 107}
 108
 109/*
 110 *      /dev/watchdog handling
 111 */
 112
 113static ssize_t advwdt_write(struct file *file, const char __user *buf,
 114                                                size_t count, loff_t *ppos)
 115{
 116        if (count) {
 117                if (!nowayout) {
 118                        size_t i;
 119
 120                        adv_expect_close = 0;
 121
 122                        for (i = 0; i != count; i++) {
 123                                char c;
 124                                if (get_user(c, buf + i))
 125                                        return -EFAULT;
 126                                if (c == 'V')
 127                                        adv_expect_close = 42;
 128                        }
 129                }
 130                advwdt_ping();
 131        }
 132        return count;
 133}
 134
 135static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 136{
 137        int new_timeout;
 138        void __user *argp = (void __user *)arg;
 139        int __user *p = argp;
 140        static const struct watchdog_info ident = {
 141                .options = WDIOF_KEEPALIVEPING |
 142                           WDIOF_SETTIMEOUT |
 143                           WDIOF_MAGICCLOSE,
 144                .firmware_version = 1,
 145                .identity = WATCHDOG_NAME,
 146        };
 147
 148        switch (cmd) {
 149        case WDIOC_GETSUPPORT:
 150                if (copy_to_user(argp, &ident, sizeof(ident)))
 151                        return -EFAULT;
 152                break;
 153
 154        case WDIOC_GETSTATUS:
 155        case WDIOC_GETBOOTSTATUS:
 156                return put_user(0, p);
 157
 158        case WDIOC_SETOPTIONS:
 159        {
 160                int options, retval = -EINVAL;
 161
 162                if (get_user(options, p))
 163                        return -EFAULT;
 164                if (options & WDIOS_DISABLECARD) {
 165                        advwdt_disable();
 166                        retval = 0;
 167                }
 168                if (options & WDIOS_ENABLECARD) {
 169                        advwdt_ping();
 170                        retval = 0;
 171                }
 172                return retval;
 173        }
 174        case WDIOC_KEEPALIVE:
 175                advwdt_ping();
 176                break;
 177
 178        case WDIOC_SETTIMEOUT:
 179                if (get_user(new_timeout, p))
 180                        return -EFAULT;
 181                if (advwdt_set_heartbeat(new_timeout))
 182                        return -EINVAL;
 183                advwdt_ping();
 184                /* Fall */
 185        case WDIOC_GETTIMEOUT:
 186                return put_user(timeout, p);
 187        default:
 188                return -ENOTTY;
 189        }
 190        return 0;
 191}
 192
 193static int advwdt_open(struct inode *inode, struct file *file)
 194{
 195        if (test_and_set_bit(0, &advwdt_is_open))
 196                return -EBUSY;
 197        /*
 198         *      Activate
 199         */
 200
 201        advwdt_ping();
 202        return nonseekable_open(inode, file);
 203}
 204
 205static int advwdt_close(struct inode *inode, struct file *file)
 206{
 207        if (adv_expect_close == 42) {
 208                advwdt_disable();
 209        } else {
 210                pr_crit("Unexpected close, not stopping watchdog!\n");
 211                advwdt_ping();
 212        }
 213        clear_bit(0, &advwdt_is_open);
 214        adv_expect_close = 0;
 215        return 0;
 216}
 217
 218/*
 219 *      Kernel Interfaces
 220 */
 221
 222static const struct file_operations advwdt_fops = {
 223        .owner          = THIS_MODULE,
 224        .llseek         = no_llseek,
 225        .write          = advwdt_write,
 226        .unlocked_ioctl = advwdt_ioctl,
 227        .open           = advwdt_open,
 228        .release        = advwdt_close,
 229};
 230
 231static struct miscdevice advwdt_miscdev = {
 232        .minor  = WATCHDOG_MINOR,
 233        .name   = "watchdog",
 234        .fops   = &advwdt_fops,
 235};
 236
 237/*
 238 *      Init & exit routines
 239 */
 240
 241static int __devinit advwdt_probe(struct platform_device *dev)
 242{
 243        int ret;
 244
 245        if (wdt_stop != wdt_start) {
 246                if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 247                        pr_err("I/O address 0x%04x already in use\n",
 248                               wdt_stop);
 249                        ret = -EIO;
 250                        goto out;
 251                }
 252        }
 253
 254        if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 255                pr_err("I/O address 0x%04x already in use\n", wdt_start);
 256                ret = -EIO;
 257                goto unreg_stop;
 258        }
 259
 260        /* Check that the heartbeat value is within it's range ;
 261         * if not reset to the default */
 262        if (advwdt_set_heartbeat(timeout)) {
 263                advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 264                pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
 265        }
 266
 267        ret = misc_register(&advwdt_miscdev);
 268        if (ret != 0) {
 269                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 270                       WATCHDOG_MINOR, ret);
 271                goto unreg_regions;
 272        }
 273        pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 274                timeout, nowayout);
 275out:
 276        return ret;
 277unreg_regions:
 278        release_region(wdt_start, 1);
 279unreg_stop:
 280        if (wdt_stop != wdt_start)
 281                release_region(wdt_stop, 1);
 282        goto out;
 283}
 284
 285static int __devexit advwdt_remove(struct platform_device *dev)
 286{
 287        misc_deregister(&advwdt_miscdev);
 288        release_region(wdt_start, 1);
 289        if (wdt_stop != wdt_start)
 290                release_region(wdt_stop, 1);
 291
 292        return 0;
 293}
 294
 295static void advwdt_shutdown(struct platform_device *dev)
 296{
 297        /* Turn the WDT off if we have a soft shutdown */
 298        advwdt_disable();
 299}
 300
 301static struct platform_driver advwdt_driver = {
 302        .probe          = advwdt_probe,
 303        .remove         = __devexit_p(advwdt_remove),
 304        .shutdown       = advwdt_shutdown,
 305        .driver         = {
 306                .owner  = THIS_MODULE,
 307                .name   = DRV_NAME,
 308        },
 309};
 310
 311static int __init advwdt_init(void)
 312{
 313        int err;
 314
 315        pr_info("WDT driver for Advantech single board computer initialising\n");
 316
 317        err = platform_driver_register(&advwdt_driver);
 318        if (err)
 319                return err;
 320
 321        advwdt_platform_device = platform_device_register_simple(DRV_NAME,
 322                                                                -1, NULL, 0);
 323        if (IS_ERR(advwdt_platform_device)) {
 324                err = PTR_ERR(advwdt_platform_device);
 325                goto unreg_platform_driver;
 326        }
 327
 328        return 0;
 329
 330unreg_platform_driver:
 331        platform_driver_unregister(&advwdt_driver);
 332        return err;
 333}
 334
 335static void __exit advwdt_exit(void)
 336{
 337        platform_device_unregister(advwdt_platform_device);
 338        platform_driver_unregister(&advwdt_driver);
 339        pr_info("Watchdog Module Unloaded\n");
 340}
 341
 342module_init(advwdt_init);
 343module_exit(advwdt_exit);
 344
 345MODULE_LICENSE("GPL");
 346MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 347MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
 348MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 349
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