linux/drivers/watchdog/wdt977.c
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   1/*
   2 *      Wdt977  0.04:   A Watchdog Device for Netwinder W83977AF chip
   3 *
   4 *      (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)
   5 *
   6 *                      -----------------------
   7 *
   8 *      This program is free software; you can redistribute it and/or
   9 *      modify it under the terms of the GNU General Public License
  10 *      as published by the Free Software Foundation; either version
  11 *      2 of the License, or (at your option) any later version.
  12 *
  13 *                      -----------------------
  14 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  15 *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  16 *      19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface
  17 *      06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts
  18 *                                  from minutes to seconds.
  19 *      07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in
  20 *                                    nwwatchdog_init.
  21 *      25-Oct-2005 Woody Suwalski: Convert addresses to #defs, add spinlocks
  22 *                                  remove limitiation to be used on
  23 *                                  Netwinders only
  24 */
  25
  26#include <linux/module.h>
  27#include <linux/moduleparam.h>
  28#include <linux/types.h>
  29#include <linux/kernel.h>
  30#include <linux/fs.h>
  31#include <linux/miscdevice.h>
  32#include <linux/init.h>
  33#include <linux/ioport.h>
  34#include <linux/watchdog.h>
  35#include <linux/notifier.h>
  36#include <linux/reboot.h>
  37#include <linux/io.h>
  38#include <linux/uaccess.h>
  39
  40#include <asm/system.h>
  41#include <asm/mach-types.h>
  42
  43#define WATCHDOG_VERSION  "0.04"
  44#define WATCHDOG_NAME     "Wdt977"
  45#define PFX WATCHDOG_NAME ": "
  46#define DRIVER_VERSION    WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"
  47
  48#define IO_INDEX_PORT   0x370           /* on some systems it can be 0x3F0 */
  49#define IO_DATA_PORT    (IO_INDEX_PORT + 1)
  50
  51#define UNLOCK_DATA     0x87
  52#define LOCK_DATA       0xAA
  53#define DEVICE_REGISTER 0x07
  54
  55
  56#define DEFAULT_TIMEOUT 60                      /* default timeout in seconds */
  57
  58static  int timeout = DEFAULT_TIMEOUT;
  59static  int timeoutM;                           /* timeout in minutes */
  60static  unsigned long timer_alive;
  61static  int testmode;
  62static  char expect_close;
  63static  DEFINE_SPINLOCK(spinlock);
  64
  65module_param(timeout, int, 0);
  66MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (60..15300), default="
  67                                __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  68module_param(testmode, int, 0);
  69MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
  70
  71static int nowayout = WATCHDOG_NOWAYOUT;
  72module_param(nowayout, int, 0);
  73MODULE_PARM_DESC(nowayout,
  74                "Watchdog cannot be stopped once started (default="
  75                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  76
  77/*
  78 * Start the watchdog
  79 */
  80
  81static int wdt977_start(void)
  82{
  83        unsigned long flags;
  84
  85        spin_lock_irqsave(&spinlock, flags);
  86
  87        /* unlock the SuperIO chip */
  88        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  89        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  90
  91        /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
  92         * F2 has the timeout in minutes
  93         * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
  94         *   at timeout, and to reset timer on kbd/mouse activity (not impl.)
  95         * F4 is used to just clear the TIMEOUT'ed state (bit 0)
  96         */
  97        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  98        outb_p(0x08, IO_DATA_PORT);
  99        outb_p(0xF2, IO_INDEX_PORT);
 100        outb_p(timeoutM, IO_DATA_PORT);
 101        outb_p(0xF3, IO_INDEX_PORT);
 102        outb_p(0x00, IO_DATA_PORT);     /* another setting is 0E for
 103                                           kbd/mouse/LED */
 104        outb_p(0xF4, IO_INDEX_PORT);
 105        outb_p(0x00, IO_DATA_PORT);
 106
 107        /* At last select device Aux1 (dev=7) and set GP16 as a
 108         * watchdog output. In test mode watch the bit 1 on F4 to
 109         * indicate "triggered"
 110         */
 111        if (!testmode) {
 112                outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 113                outb_p(0x07, IO_DATA_PORT);
 114                outb_p(0xE6, IO_INDEX_PORT);
 115                outb_p(0x08, IO_DATA_PORT);
 116        }
 117
 118        /* lock the SuperIO chip */
 119        outb_p(LOCK_DATA, IO_INDEX_PORT);
 120
 121        spin_unlock_irqrestore(&spinlock, flags);
 122        printk(KERN_INFO PFX "activated.\n");
 123
 124        return 0;
 125}
 126
 127/*
 128 * Stop the watchdog
 129 */
 130
 131static int wdt977_stop(void)
 132{
 133        unsigned long flags;
 134        spin_lock_irqsave(&spinlock, flags);
 135
 136        /* unlock the SuperIO chip */
 137        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 138        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 139
 140        /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
 141        * F3 is reset to its default state
 142        * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
 143        * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
 144        */
 145        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 146        outb_p(0x08, IO_DATA_PORT);
 147        outb_p(0xF2, IO_INDEX_PORT);
 148        outb_p(0xFF, IO_DATA_PORT);
 149        outb_p(0xF3, IO_INDEX_PORT);
 150        outb_p(0x00, IO_DATA_PORT);
 151        outb_p(0xF4, IO_INDEX_PORT);
 152        outb_p(0x00, IO_DATA_PORT);
 153        outb_p(0xF2, IO_INDEX_PORT);
 154        outb_p(0x00, IO_DATA_PORT);
 155
 156        /* at last select device Aux1 (dev=7) and set
 157           GP16 as a watchdog output */
 158        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 159        outb_p(0x07, IO_DATA_PORT);
 160        outb_p(0xE6, IO_INDEX_PORT);
 161        outb_p(0x08, IO_DATA_PORT);
 162
 163        /* lock the SuperIO chip */
 164        outb_p(LOCK_DATA, IO_INDEX_PORT);
 165
 166        spin_unlock_irqrestore(&spinlock, flags);
 167        printk(KERN_INFO PFX "shutdown.\n");
 168
 169        return 0;
 170}
 171
 172/*
 173 * Send a keepalive ping to the watchdog
 174 * This is done by simply re-writing the timeout to reg. 0xF2
 175 */
 176
 177static int wdt977_keepalive(void)
 178{
 179        unsigned long flags;
 180        spin_lock_irqsave(&spinlock, flags);
 181
 182        /* unlock the SuperIO chip */
 183        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 184        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 185
 186        /* select device Aux2 (device=8) and kicks watchdog reg F2 */
 187        /* F2 has the timeout in minutes */
 188        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 189        outb_p(0x08, IO_DATA_PORT);
 190        outb_p(0xF2, IO_INDEX_PORT);
 191        outb_p(timeoutM, IO_DATA_PORT);
 192
 193        /* lock the SuperIO chip */
 194        outb_p(LOCK_DATA, IO_INDEX_PORT);
 195        spin_unlock_irqrestore(&spinlock, flags);
 196
 197        return 0;
 198}
 199
 200/*
 201 * Set the watchdog timeout value
 202 */
 203
 204static int wdt977_set_timeout(int t)
 205{
 206        int tmrval;
 207
 208        /* convert seconds to minutes, rounding up */
 209        tmrval = (t + 59) / 60;
 210
 211        if (machine_is_netwinder()) {
 212                /* we have a hw bug somewhere, so each 977 minute is actually
 213                 * only 30sec. This limits the max timeout to half of device
 214                 * max of 255 minutes...
 215                 */
 216                tmrval += tmrval;
 217        }
 218
 219        if (tmrval < 1 || tmrval > 255)
 220                return -EINVAL;
 221
 222        /* timeout is the timeout in seconds, timeoutM is
 223           the timeout in minutes) */
 224        timeout = t;
 225        timeoutM = tmrval;
 226        return 0;
 227}
 228
 229/*
 230 * Get the watchdog status
 231 */
 232
 233static int wdt977_get_status(int *status)
 234{
 235        int new_status;
 236        unsigned long flags;
 237
 238        spin_lock_irqsave(&spinlock, flags);
 239
 240        /* unlock the SuperIO chip */
 241        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 242        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 243
 244        /* select device Aux2 (device=8) and read watchdog reg F4 */
 245        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 246        outb_p(0x08, IO_DATA_PORT);
 247        outb_p(0xF4, IO_INDEX_PORT);
 248        new_status = inb_p(IO_DATA_PORT);
 249
 250        /* lock the SuperIO chip */
 251        outb_p(LOCK_DATA, IO_INDEX_PORT);
 252
 253        spin_unlock_irqrestore(&spinlock, flags);
 254
 255        *status = 0;
 256        if (new_status & 1)
 257                *status |= WDIOF_CARDRESET;
 258
 259        return 0;
 260}
 261
 262
 263/*
 264 *      /dev/watchdog handling
 265 */
 266
 267static int wdt977_open(struct inode *inode, struct file *file)
 268{
 269        /* If the watchdog is alive we don't need to start it again */
 270        if (test_and_set_bit(0, &timer_alive))
 271                return -EBUSY;
 272
 273        if (nowayout)
 274                __module_get(THIS_MODULE);
 275
 276        wdt977_start();
 277        return nonseekable_open(inode, file);
 278}
 279
 280static int wdt977_release(struct inode *inode, struct file *file)
 281{
 282        /*
 283         *      Shut off the timer.
 284         *      Lock it in if it's a module and we set nowayout
 285         */
 286        if (expect_close == 42) {
 287                wdt977_stop();
 288                clear_bit(0, &timer_alive);
 289        } else {
 290                wdt977_keepalive();
 291                printk(KERN_CRIT PFX
 292                        "Unexpected close, not stopping watchdog!\n");
 293        }
 294        expect_close = 0;
 295        return 0;
 296}
 297
 298
 299/*
 300 *      wdt977_write:
 301 *      @file: file handle to the watchdog
 302 *      @buf: buffer to write (unused as data does not matter here
 303 *      @count: count of bytes
 304 *      @ppos: pointer to the position to write. No seeks allowed
 305 *
 306 *      A write to a watchdog device is defined as a keepalive signal. Any
 307 *      write of data will do, as we we don't define content meaning.
 308 */
 309
 310static ssize_t wdt977_write(struct file *file, const char __user *buf,
 311                            size_t count, loff_t *ppos)
 312{
 313        if (count) {
 314                if (!nowayout) {
 315                        size_t i;
 316
 317                        /* In case it was set long ago */
 318                        expect_close = 0;
 319
 320                        for (i = 0; i != count; i++) {
 321                                char c;
 322                                if (get_user(c, buf + i))
 323                                        return -EFAULT;
 324                                if (c == 'V')
 325                                        expect_close = 42;
 326                        }
 327                }
 328
 329                /* someone wrote to us, we should restart timer */
 330                wdt977_keepalive();
 331        }
 332        return count;
 333}
 334
 335static const struct watchdog_info ident = {
 336        .options =              WDIOF_SETTIMEOUT |
 337                                WDIOF_MAGICCLOSE |
 338                                WDIOF_KEEPALIVEPING,
 339        .firmware_version =     1,
 340        .identity =             WATCHDOG_NAME,
 341};
 342
 343/*
 344 *      wdt977_ioctl:
 345 *      @inode: inode of the device
 346 *      @file: file handle to the device
 347 *      @cmd: watchdog command
 348 *      @arg: argument pointer
 349 *
 350 *      The watchdog API defines a common set of functions for all watchdogs
 351 *      according to their available features.
 352 */
 353
 354static long wdt977_ioctl(struct file *file, unsigned int cmd,
 355                                                        unsigned long arg)
 356{
 357        int status;
 358        int new_options, retval = -EINVAL;
 359        int new_timeout;
 360        union {
 361                struct watchdog_info __user *ident;
 362                int __user *i;
 363        } uarg;
 364
 365        uarg.i = (int __user *)arg;
 366
 367        switch (cmd) {
 368        case WDIOC_GETSUPPORT:
 369                return copy_to_user(uarg.ident, &ident,
 370                        sizeof(ident)) ? -EFAULT : 0;
 371
 372        case WDIOC_GETSTATUS:
 373                wdt977_get_status(&status);
 374                return put_user(status, uarg.i);
 375
 376        case WDIOC_GETBOOTSTATUS:
 377                return put_user(0, uarg.i);
 378
 379        case WDIOC_SETOPTIONS:
 380                if (get_user(new_options, uarg.i))
 381                        return -EFAULT;
 382
 383                if (new_options & WDIOS_DISABLECARD) {
 384                        wdt977_stop();
 385                        retval = 0;
 386                }
 387
 388                if (new_options & WDIOS_ENABLECARD) {
 389                        wdt977_start();
 390                        retval = 0;
 391                }
 392
 393                return retval;
 394
 395        case WDIOC_KEEPALIVE:
 396                wdt977_keepalive();
 397                return 0;
 398
 399        case WDIOC_SETTIMEOUT:
 400                if (get_user(new_timeout, uarg.i))
 401                        return -EFAULT;
 402
 403                if (wdt977_set_timeout(new_timeout))
 404                    return -EINVAL;
 405
 406                wdt977_keepalive();
 407                /* Fall */
 408
 409        case WDIOC_GETTIMEOUT:
 410                return put_user(timeout, uarg.i);
 411
 412        default:
 413                return -ENOTTY;
 414
 415        }
 416}
 417
 418static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
 419        void *unused)
 420{
 421        if (code == SYS_DOWN || code == SYS_HALT)
 422                wdt977_stop();
 423        return NOTIFY_DONE;
 424}
 425
 426static const struct file_operations wdt977_fops = {
 427        .owner          = THIS_MODULE,
 428        .llseek         = no_llseek,
 429        .write          = wdt977_write,
 430        .unlocked_ioctl = wdt977_ioctl,
 431        .open           = wdt977_open,
 432        .release        = wdt977_release,
 433};
 434
 435static struct miscdevice wdt977_miscdev = {
 436        .minor          = WATCHDOG_MINOR,
 437        .name           = "watchdog",
 438        .fops           = &wdt977_fops,
 439};
 440
 441static struct notifier_block wdt977_notifier = {
 442        .notifier_call = wdt977_notify_sys,
 443};
 444
 445static int __init wd977_init(void)
 446{
 447        int rc;
 448
 449        printk(KERN_INFO PFX DRIVER_VERSION);
 450
 451        /* Check that the timeout value is within its range;
 452           if not reset to the default */
 453        if (wdt977_set_timeout(timeout)) {
 454                wdt977_set_timeout(DEFAULT_TIMEOUT);
 455                printk(KERN_INFO PFX
 456                      "timeout value must be 60 < timeout < 15300, using %d\n",
 457                                                        DEFAULT_TIMEOUT);
 458        }
 459
 460        /* on Netwinder the IOports are already reserved by
 461         * arch/arm/mach-footbridge/netwinder-hw.c
 462         */
 463        if (!machine_is_netwinder()) {
 464                if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 465                        printk(KERN_ERR PFX
 466                                "I/O address 0x%04x already in use\n",
 467                                                                IO_INDEX_PORT);
 468                        rc = -EIO;
 469                        goto err_out;
 470                }
 471        }
 472
 473        rc = register_reboot_notifier(&wdt977_notifier);
 474        if (rc) {
 475                printk(KERN_ERR PFX
 476                        "cannot register reboot notifier (err=%d)\n", rc);
 477                goto err_out_region;
 478        }
 479
 480        rc = misc_register(&wdt977_miscdev);
 481        if (rc) {
 482                printk(KERN_ERR PFX
 483                        "cannot register miscdev on minor=%d (err=%d)\n",
 484                                                wdt977_miscdev.minor, rc);
 485                goto err_out_reboot;
 486        }
 487
 488        printk(KERN_INFO PFX
 489                "initialized. timeout=%d sec (nowayout=%d, testmode=%i)\n",
 490                                                timeout, nowayout, testmode);
 491
 492        return 0;
 493
 494err_out_reboot:
 495        unregister_reboot_notifier(&wdt977_notifier);
 496err_out_region:
 497        if (!machine_is_netwinder())
 498                release_region(IO_INDEX_PORT, 2);
 499err_out:
 500        return rc;
 501}
 502
 503static void __exit wd977_exit(void)
 504{
 505        wdt977_stop();
 506        misc_deregister(&wdt977_miscdev);
 507        unregister_reboot_notifier(&wdt977_notifier);
 508        release_region(IO_INDEX_PORT, 2);
 509}
 510
 511module_init(wd977_init);
 512module_exit(wd977_exit);
 513
 514MODULE_AUTHOR("Woody Suwalski <woodys@xandros.com>");
 515MODULE_DESCRIPTION("W83977AF Watchdog driver");
 516MODULE_LICENSE("GPL");
 517MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 518