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