linux/drivers/watchdog/w83697ug_wdt.c
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   1/*
   2 *      w83697ug/uf WDT driver
   3 *
   4 *      (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
   5 *              reused original code to support w83697ug/uf.
   6 *
   7 *      Based on w83627hf_wdt.c which is based on advantechwdt.c
   8 *      which is based on wdt.c.
   9 *      Original copyright messages:
  10 *
  11 *      (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
  12 *              added support for W83627THF.
  13 *
  14 *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  15 *
  16 *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  17 *
  18 *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  19 *                              http://www.redhat.com
  20 *
  21 *      This program is free software; you can redistribute it and/or
  22 *      modify it under the terms of the GNU General Public License
  23 *      as published by the Free Software Foundation; either version
  24 *      2 of the License, or (at your option) any later version.
  25 *
  26 *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  27 *      warranty for any of this software. This material is provided
  28 *      "AS-IS" and at no charge.
  29 *
  30 *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  31 */
  32
  33#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  34
  35#include <linux/module.h>
  36#include <linux/moduleparam.h>
  37#include <linux/types.h>
  38#include <linux/miscdevice.h>
  39#include <linux/watchdog.h>
  40#include <linux/fs.h>
  41#include <linux/ioport.h>
  42#include <linux/notifier.h>
  43#include <linux/reboot.h>
  44#include <linux/init.h>
  45#include <linux/spinlock.h>
  46#include <linux/io.h>
  47#include <linux/uaccess.h>
  48
  49
  50#define WATCHDOG_NAME "w83697ug/uf WDT"
  51#define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  52
  53static unsigned long wdt_is_open;
  54static char expect_close;
  55static DEFINE_SPINLOCK(io_lock);
  56
  57static int wdt_io = 0x2e;
  58module_param(wdt_io, int, 0);
  59MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
  60
  61static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  62module_param(timeout, int, 0);
  63MODULE_PARM_DESC(timeout,
  64        "Watchdog timeout in seconds. 1<= timeout <=255 (default="
  65                                __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  66
  67static bool nowayout = WATCHDOG_NOWAYOUT;
  68module_param(nowayout, bool, 0);
  69MODULE_PARM_DESC(nowayout,
  70        "Watchdog cannot be stopped once started (default="
  71                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  72
  73/*
  74 *      Kernel methods.
  75 */
  76
  77#define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  78#define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
  79                                                        (same as EFER) */
  80#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  81
  82static int w83697ug_select_wd_register(void)
  83{
  84        unsigned char c;
  85        unsigned char version;
  86
  87        outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  88        outb_p(0x87, WDT_EFER); /* Again according to manual */
  89
  90        outb(0x20, WDT_EFER);   /* check chip version   */
  91        version = inb(WDT_EFDR);
  92
  93        if (version == 0x68) {  /* W83697UG             */
  94                pr_info("Watchdog chip version 0x%02x = W83697UG/UF found at 0x%04x\n",
  95                        version, wdt_io);
  96
  97                outb_p(0x2b, WDT_EFER);
  98                c = inb_p(WDT_EFDR);    /* select WDT0 */
  99                c &= ~0x04;
 100                outb_p(0x2b, WDT_EFER);
 101                outb_p(c, WDT_EFDR);    /* set pin118 to WDT0 */
 102
 103        } else {
 104                pr_err("No W83697UG/UF could be found\n");
 105                return -ENODEV;
 106        }
 107
 108        outb_p(0x07, WDT_EFER); /* point to logical device number reg */
 109        outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
 110        outb_p(0x30, WDT_EFER); /* select CR30 */
 111        c = inb_p(WDT_EFDR);
 112        outb_p(c | 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
 113
 114        return 0;
 115}
 116
 117static void w83697ug_unselect_wd_register(void)
 118{
 119        outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
 120}
 121
 122static int w83697ug_init(void)
 123{
 124        int ret;
 125        unsigned char t;
 126
 127        ret = w83697ug_select_wd_register();
 128        if (ret != 0)
 129                return ret;
 130
 131        outb_p(0xF6, WDT_EFER); /* Select CRF6 */
 132        t = inb_p(WDT_EFDR);    /* read CRF6 */
 133        if (t != 0) {
 134                pr_info("Watchdog already running. Resetting timeout to %d sec\n",
 135                        timeout);
 136                outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 137        }
 138        outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 139        t = inb_p(WDT_EFDR);    /* read CRF5 */
 140        t &= ~0x0C;             /* set second mode &
 141                                        disable keyboard turning off watchdog */
 142        outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 143
 144        w83697ug_unselect_wd_register();
 145        return 0;
 146}
 147
 148static void wdt_ctrl(int timeout)
 149{
 150        spin_lock(&io_lock);
 151
 152        if (w83697ug_select_wd_register() < 0) {
 153                spin_unlock(&io_lock);
 154                return;
 155        }
 156
 157        outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
 158        outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
 159
 160        w83697ug_unselect_wd_register();
 161
 162        spin_unlock(&io_lock);
 163}
 164
 165static int wdt_ping(void)
 166{
 167        wdt_ctrl(timeout);
 168        return 0;
 169}
 170
 171static int wdt_disable(void)
 172{
 173        wdt_ctrl(0);
 174        return 0;
 175}
 176
 177static int wdt_set_heartbeat(int t)
 178{
 179        if (t < 1 || t > 255)
 180                return -EINVAL;
 181
 182        timeout = t;
 183        return 0;
 184}
 185
 186static ssize_t wdt_write(struct file *file, const char __user *buf,
 187                                                size_t count, loff_t *ppos)
 188{
 189        if (count) {
 190                if (!nowayout) {
 191                        size_t i;
 192
 193                        expect_close = 0;
 194
 195                        for (i = 0; i != count; i++) {
 196                                char c;
 197                                if (get_user(c, buf + i))
 198                                        return -EFAULT;
 199                                if (c == 'V')
 200                                        expect_close = 42;
 201                        }
 202                }
 203                wdt_ping();
 204        }
 205        return count;
 206}
 207
 208static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 209{
 210        void __user *argp = (void __user *)arg;
 211        int __user *p = argp;
 212        int new_timeout;
 213        static const struct watchdog_info ident = {
 214                .options =              WDIOF_KEEPALIVEPING |
 215                                        WDIOF_SETTIMEOUT |
 216                                        WDIOF_MAGICCLOSE,
 217                .firmware_version =     1,
 218                .identity =             "W83697UG WDT",
 219        };
 220
 221        switch (cmd) {
 222        case WDIOC_GETSUPPORT:
 223                if (copy_to_user(argp, &ident, sizeof(ident)))
 224                        return -EFAULT;
 225                break;
 226
 227        case WDIOC_GETSTATUS:
 228        case WDIOC_GETBOOTSTATUS:
 229                return put_user(0, 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                        wdt_disable();
 240                        retval = 0;
 241                }
 242
 243                if (options & WDIOS_ENABLECARD) {
 244                        wdt_ping();
 245                        retval = 0;
 246                }
 247
 248                return retval;
 249        }
 250
 251        case WDIOC_KEEPALIVE:
 252                wdt_ping();
 253                break;
 254
 255        case WDIOC_SETTIMEOUT:
 256                if (get_user(new_timeout, p))
 257                        return -EFAULT;
 258                if (wdt_set_heartbeat(new_timeout))
 259                        return -EINVAL;
 260                wdt_ping();
 261                /* Fall */
 262
 263        case WDIOC_GETTIMEOUT:
 264                return put_user(timeout, p);
 265
 266        default:
 267                return -ENOTTY;
 268        }
 269        return 0;
 270}
 271
 272static int wdt_open(struct inode *inode, struct file *file)
 273{
 274        if (test_and_set_bit(0, &wdt_is_open))
 275                return -EBUSY;
 276        /*
 277         *      Activate
 278         */
 279
 280        wdt_ping();
 281        return nonseekable_open(inode, file);
 282}
 283
 284static int wdt_close(struct inode *inode, struct file *file)
 285{
 286        if (expect_close == 42)
 287                wdt_disable();
 288        else {
 289                pr_crit("Unexpected close, not stopping watchdog!\n");
 290                wdt_ping();
 291        }
 292        expect_close = 0;
 293        clear_bit(0, &wdt_is_open);
 294        return 0;
 295}
 296
 297/*
 298 *      Notifier for system down
 299 */
 300
 301static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 302        void *unused)
 303{
 304        if (code == SYS_DOWN || code == SYS_HALT)
 305                wdt_disable();  /* Turn the WDT off */
 306
 307        return NOTIFY_DONE;
 308}
 309
 310/*
 311 *      Kernel Interfaces
 312 */
 313
 314static const struct file_operations wdt_fops = {
 315        .owner          = THIS_MODULE,
 316        .llseek         = no_llseek,
 317        .write          = wdt_write,
 318        .unlocked_ioctl = wdt_ioctl,
 319        .open           = wdt_open,
 320        .release        = wdt_close,
 321};
 322
 323static struct miscdevice wdt_miscdev = {
 324        .minor = WATCHDOG_MINOR,
 325        .name = "watchdog",
 326        .fops = &wdt_fops,
 327};
 328
 329/*
 330 *      The WDT needs to learn about soft shutdowns in order to
 331 *      turn the timebomb registers off.
 332 */
 333
 334static struct notifier_block wdt_notifier = {
 335        .notifier_call = wdt_notify_sys,
 336};
 337
 338static int __init wdt_init(void)
 339{
 340        int ret;
 341
 342        pr_info("WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising\n");
 343
 344        if (wdt_set_heartbeat(timeout)) {
 345                wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 346                pr_info("timeout value must be 1<=timeout<=255, using %d\n",
 347                        WATCHDOG_TIMEOUT);
 348        }
 349
 350        if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 351                pr_err("I/O address 0x%04x already in use\n", wdt_io);
 352                ret = -EIO;
 353                goto out;
 354        }
 355
 356        ret = w83697ug_init();
 357        if (ret != 0)
 358                goto unreg_regions;
 359
 360        ret = register_reboot_notifier(&wdt_notifier);
 361        if (ret != 0) {
 362                pr_err("cannot register reboot notifier (err=%d)\n", ret);
 363                goto unreg_regions;
 364        }
 365
 366        ret = misc_register(&wdt_miscdev);
 367        if (ret != 0) {
 368                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 369                       WATCHDOG_MINOR, ret);
 370                goto unreg_reboot;
 371        }
 372
 373        pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 374                timeout, nowayout);
 375
 376out:
 377        return ret;
 378unreg_reboot:
 379        unregister_reboot_notifier(&wdt_notifier);
 380unreg_regions:
 381        release_region(wdt_io, 1);
 382        goto out;
 383}
 384
 385static void __exit wdt_exit(void)
 386{
 387        misc_deregister(&wdt_miscdev);
 388        unregister_reboot_notifier(&wdt_notifier);
 389        release_region(wdt_io, 1);
 390}
 391
 392module_init(wdt_init);
 393module_exit(wdt_exit);
 394
 395MODULE_LICENSE("GPL");
 396MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
 397MODULE_DESCRIPTION("w83697ug/uf WDT driver");
 398MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 399
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