LXR linux/drivers/watchdog/wdt977.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      Wdt977  0.04:   A Watchdog Device for Netwinder W83977AF chip
   4 *
   5 *      (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)
   6 *
   7 *                      -----------------------
   8 *
   9 *                      -----------------------
  10 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  11 *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  12 *      19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface
  13 *      06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts
  14 *                                  from minutes to seconds.
  15 *      07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in
  16 *                                    nwwatchdog_init.
  17 *      25-Oct-2005 Woody Suwalski: Convert addresses to #defs, add spinlocks
  18 *                                  remove limitiation to be used on
  19 *                                  Netwinders only
  20 */
  21
  22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  23
  24#include <linux/module.h>
  25#include <linux/moduleparam.h>
  26#include <linux/types.h>
  27#include <linux/kernel.h>
  28#include <linux/fs.h>
  29#include <linux/miscdevice.h>
  30#include <linux/init.h>
  31#include <linux/ioport.h>
  32#include <linux/watchdog.h>
  33#include <linux/notifier.h>
  34#include <linux/reboot.h>
  35#include <linux/io.h>
  36#include <linux/uaccess.h>
  37
  38#include <asm/mach-types.h>
  39
  40#define WATCHDOG_VERSION  "0.04"
  41#define WATCHDOG_NAME     "Wdt977"
  42
  43#define IO_INDEX_PORT   0x370           /* on some systems it can be 0x3F0 */
  44#define IO_DATA_PORT    (IO_INDEX_PORT + 1)
  45
  46#define UNLOCK_DATA     0x87
  47#define LOCK_DATA       0xAA
  48#define DEVICE_REGISTER 0x07
  49
  50
  51#define DEFAULT_TIMEOUT 60                      /* default timeout in seconds */
  52
  53static  int timeout = DEFAULT_TIMEOUT;
  54static  int timeoutM;                           /* timeout in minutes */
  55static  unsigned long timer_alive;
  56static  int testmode;
  57static  char expect_close;
  58static  DEFINE_SPINLOCK(spinlock);
  59
  60module_param(timeout, int, 0);
  61MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (60..15300, default="
  62                                __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  63module_param(testmode, int, 0);
  64MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
  65
  66static bool nowayout = WATCHDOG_NOWAYOUT;
  67module_param(nowayout, bool, 0);
  68MODULE_PARM_DESC(nowayout,
  69                "Watchdog cannot be stopped once started (default="
  70                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  71
  72/*
  73 * Start the watchdog
  74 */
  75
  76static int wdt977_start(void)
  77{
  78        unsigned long flags;
  79
  80        spin_lock_irqsave(&spinlock, flags);
  81
  82        /* unlock the SuperIO chip */
  83        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  84        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  85
  86        /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
  87         * F2 has the timeout in minutes
  88         * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
  89         *   at timeout, and to reset timer on kbd/mouse activity (not impl.)
  90         * F4 is used to just clear the TIMEOUT'ed state (bit 0)
  91         */
  92        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  93        outb_p(0x08, IO_DATA_PORT);
  94        outb_p(0xF2, IO_INDEX_PORT);
  95        outb_p(timeoutM, IO_DATA_PORT);
  96        outb_p(0xF3, IO_INDEX_PORT);
  97        outb_p(0x00, IO_DATA_PORT);     /* another setting is 0E for
  98                                           kbd/mouse/LED */
  99        outb_p(0xF4, IO_INDEX_PORT);
 100        outb_p(0x00, IO_DATA_PORT);
 101
 102        /* At last select device Aux1 (dev=7) and set GP16 as a
 103         * watchdog output. In test mode watch the bit 1 on F4 to
 104         * indicate "triggered"
 105         */
 106        if (!testmode) {
 107                outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 108                outb_p(0x07, IO_DATA_PORT);
 109                outb_p(0xE6, IO_INDEX_PORT);
 110                outb_p(0x08, IO_DATA_PORT);
 111        }
 112
 113        /* lock the SuperIO chip */
 114        outb_p(LOCK_DATA, IO_INDEX_PORT);
 115
 116        spin_unlock_irqrestore(&spinlock, flags);
 117        pr_info("activated\n");
 118
 119        return 0;
 120}
 121
 122/*
 123 * Stop the watchdog
 124 */
 125
 126static int wdt977_stop(void)
 127{
 128        unsigned long flags;
 129        spin_lock_irqsave(&spinlock, flags);
 130
 131        /* unlock the SuperIO chip */
 132        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 133        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 134
 135        /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
 136        * F3 is reset to its default state
 137        * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
 138        * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
 139        */
 140        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 141        outb_p(0x08, IO_DATA_PORT);
 142        outb_p(0xF2, IO_INDEX_PORT);
 143        outb_p(0xFF, IO_DATA_PORT);
 144        outb_p(0xF3, IO_INDEX_PORT);
 145        outb_p(0x00, IO_DATA_PORT);
 146        outb_p(0xF4, IO_INDEX_PORT);
 147        outb_p(0x00, IO_DATA_PORT);
 148        outb_p(0xF2, IO_INDEX_PORT);
 149        outb_p(0x00, IO_DATA_PORT);
 150
 151        /* at last select device Aux1 (dev=7) and set
 152           GP16 as a watchdog output */
 153        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 154        outb_p(0x07, IO_DATA_PORT);
 155        outb_p(0xE6, IO_INDEX_PORT);
 156        outb_p(0x08, IO_DATA_PORT);
 157
 158        /* lock the SuperIO chip */
 159        outb_p(LOCK_DATA, IO_INDEX_PORT);
 160
 161        spin_unlock_irqrestore(&spinlock, flags);
 162        pr_info("shutdown\n");
 163
 164        return 0;
 165}
 166
 167/*
 168 * Send a keepalive ping to the watchdog
 169 * This is done by simply re-writing the timeout to reg. 0xF2
 170 */
 171
 172static int wdt977_keepalive(void)
 173{
 174        unsigned long flags;
 175        spin_lock_irqsave(&spinlock, flags);
 176
 177        /* unlock the SuperIO chip */
 178        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 179        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 180
 181        /* select device Aux2 (device=8) and kicks watchdog reg F2 */
 182        /* F2 has the timeout in minutes */
 183        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 184        outb_p(0x08, IO_DATA_PORT);
 185        outb_p(0xF2, IO_INDEX_PORT);
 186        outb_p(timeoutM, IO_DATA_PORT);
 187
 188        /* lock the SuperIO chip */
 189        outb_p(LOCK_DATA, IO_INDEX_PORT);
 190        spin_unlock_irqrestore(&spinlock, flags);
 191
 192        return 0;
 193}
 194
 195/*
 196 * Set the watchdog timeout value
 197 */
 198
 199static int wdt977_set_timeout(int t)
 200{
 201        int tmrval;
 202
 203        /* convert seconds to minutes, rounding up */
 204        tmrval = (t + 59) / 60;
 205
 206        if (machine_is_netwinder()) {
 207                /* we have a hw bug somewhere, so each 977 minute is actually
 208                 * only 30sec. This limits the max timeout to half of device
 209                 * max of 255 minutes...
 210                 */
 211                tmrval += tmrval;
 212        }
 213
 214        if (tmrval < 1 || tmrval > 255)
 215                return -EINVAL;
 216
 217        /* timeout is the timeout in seconds, timeoutM is
 218           the timeout in minutes) */
 219        timeout = t;
 220        timeoutM = tmrval;
 221        return 0;
 222}
 223
 224/*
 225 * Get the watchdog status
 226 */
 227
 228static int wdt977_get_status(int *status)
 229{
 230        int new_status;
 231        unsigned long flags;
 232
 233        spin_lock_irqsave(&spinlock, flags);
 234
 235        /* unlock the SuperIO chip */
 236        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 237        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 238
 239        /* select device Aux2 (device=8) and read watchdog reg F4 */
 240        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 241        outb_p(0x08, IO_DATA_PORT);
 242        outb_p(0xF4, IO_INDEX_PORT);
 243        new_status = inb_p(IO_DATA_PORT);
 244
 245        /* lock the SuperIO chip */
 246        outb_p(LOCK_DATA, IO_INDEX_PORT);
 247
 248        spin_unlock_irqrestore(&spinlock, flags);
 249
 250        *status = 0;
 251        if (new_status & 1)
 252                *status |= WDIOF_CARDRESET;
 253
 254        return 0;
 255}
 256
 257
 258/*
 259 *      /dev/watchdog handling
 260 */
 261
 262static int wdt977_open(struct inode *inode, struct file *file)
 263{
 264        /* If the watchdog is alive we don't need to start it again */
 265        if (test_and_set_bit(0, &timer_alive))
 266                return -EBUSY;
 267
 268        if (nowayout)
 269                __module_get(THIS_MODULE);
 270
 271        wdt977_start();
 272        return stream_open(inode, file);
 273}
 274
 275static int wdt977_release(struct inode *inode, struct file *file)
 276{
 277        /*
 278         *      Shut off the timer.
 279         *      Lock it in if it's a module and we set nowayout
 280         */
 281        if (expect_close == 42) {
 282                wdt977_stop();
 283                clear_bit(0, &timer_alive);
 284        } else {
 285                wdt977_keepalive();
 286                pr_crit("Unexpected close, not stopping watchdog!\n");
 287        }
 288        expect_close = 0;
 289        return 0;
 290}
 291
 292
 293/*
 294 *      wdt977_write:
 295 *      @file: file handle to the watchdog
 296 *      @buf: buffer to write (unused as data does not matter here
 297 *      @count: count of bytes
 298 *      @ppos: pointer to the position to write. No seeks allowed
 299 *
 300 *      A write to a watchdog device is defined as a keepalive signal. Any
 301 *      write of data will do, as we we don't define content meaning.
 302 */
 303
 304static ssize_t wdt977_write(struct file *file, const char __user *buf,
 305                            size_t count, loff_t *ppos)
 306{
 307        if (count) {
 308                if (!nowayout) {
 309                        size_t i;
 310
 311                        /* In case it was set long ago */
 312                        expect_close = 0;
 313
 314                        for (i = 0; i != count; i++) {
 315                                char c;
 316                                if (get_user(c, buf + i))
 317                                        return -EFAULT;
 318                                if (c == 'V')
 319                                        expect_close = 42;
 320                        }
 321                }
 322
 323                /* someone wrote to us, we should restart timer */
 324                wdt977_keepalive();
 325        }
 326        return count;
 327}
 328
 329static const struct watchdog_info ident = {
 330        .options =              WDIOF_SETTIMEOUT |
 331                                WDIOF_MAGICCLOSE |
 332                                WDIOF_KEEPALIVEPING,
 333        .firmware_version =     1,
 334        .identity =             WATCHDOG_NAME,
 335};
 336
 337/*
 338 *      wdt977_ioctl:
 339 *      @inode: inode of the device
 340 *      @file: file handle to the device
 341 *      @cmd: watchdog command
 342 *      @arg: argument pointer
 343 *
 344 *      The watchdog API defines a common set of functions for all watchdogs
 345 *      according to their available features.
 346 */
 347
 348static long wdt977_ioctl(struct file *file, unsigned int cmd,
 349                                                        unsigned long arg)
 350{
 351        int status;
 352        int new_options, retval = -EINVAL;
 353        int new_timeout;
 354        union {
 355                struct watchdog_info __user *ident;
 356                int __user *i;
 357        } uarg;
 358
 359        uarg.i = (int __user *)arg;
 360
 361        switch (cmd) {
 362        case WDIOC_GETSUPPORT:
 363                return copy_to_user(uarg.ident, &ident,
 364                        sizeof(ident)) ? -EFAULT : 0;
 365
 366        case WDIOC_GETSTATUS:
 367                wdt977_get_status(&status);
 368                return put_user(status, uarg.i);
 369
 370        case WDIOC_GETBOOTSTATUS:
 371                return put_user(0, uarg.i);
 372
 373        case WDIOC_SETOPTIONS:
 374                if (get_user(new_options, uarg.i))
 375                        return -EFAULT;
 376
 377                if (new_options & WDIOS_DISABLECARD) {
 378                        wdt977_stop();
 379                        retval = 0;
 380                }
 381
 382                if (new_options & WDIOS_ENABLECARD) {
 383                        wdt977_start();
 384                        retval = 0;
 385                }
 386
 387                return retval;
 388
 389        case WDIOC_KEEPALIVE:
 390                wdt977_keepalive();
 391                return 0;
 392
 393        case WDIOC_SETTIMEOUT:
 394                if (get_user(new_timeout, uarg.i))
 395                        return -EFAULT;
 396
 397                if (wdt977_set_timeout(new_timeout))
 398                        return -EINVAL;
 399
 400                wdt977_keepalive();
 401                fallthrough;
 402
 403        case WDIOC_GETTIMEOUT:
 404                return put_user(timeout, uarg.i);
 405
 406        default:
 407                return -ENOTTY;
 408
 409        }
 410}
 411
 412static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
 413        void *unused)
 414{
 415        if (code == SYS_DOWN || code == SYS_HALT)
 416                wdt977_stop();
 417        return NOTIFY_DONE;
 418}
 419
 420static const struct file_operations wdt977_fops = {
 421        .owner          = THIS_MODULE,
 422        .llseek         = no_llseek,
 423        .write          = wdt977_write,
 424        .unlocked_ioctl = wdt977_ioctl,
 425        .compat_ioctl   = compat_ptr_ioctl,
 426        .open           = wdt977_open,
 427        .release        = wdt977_release,
 428};
 429
 430static struct miscdevice wdt977_miscdev = {
 431        .minor          = WATCHDOG_MINOR,
 432        .name           = "watchdog",
 433        .fops           = &wdt977_fops,
 434};
 435
 436static struct notifier_block wdt977_notifier = {
 437        .notifier_call = wdt977_notify_sys,
 438};
 439
 440static int __init wd977_init(void)
 441{
 442        int rc;
 443
 444        pr_info("driver v%s\n", WATCHDOG_VERSION);
 445
 446        /* Check that the timeout value is within its range;
 447           if not reset to the default */
 448        if (wdt977_set_timeout(timeout)) {
 449                wdt977_set_timeout(DEFAULT_TIMEOUT);
 450                pr_info("timeout value must be 60 < timeout < 15300, using %d\n",
 451                        DEFAULT_TIMEOUT);
 452        }
 453
 454        /* on Netwinder the IOports are already reserved by
 455         * arch/arm/mach-footbridge/netwinder-hw.c
 456         */
 457        if (!machine_is_netwinder()) {
 458                if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 459                        pr_err("I/O address 0x%04x already in use\n",
 460                               IO_INDEX_PORT);
 461                        rc = -EIO;
 462                        goto err_out;
 463                }
 464        }
 465
 466        rc = register_reboot_notifier(&wdt977_notifier);
 467        if (rc) {
 468                pr_err("cannot register reboot notifier (err=%d)\n", rc);
 469                goto err_out_region;
 470        }
 471
 472        rc = misc_register(&wdt977_miscdev);
 473        if (rc) {
 474                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 475                       wdt977_miscdev.minor, rc);
 476                goto err_out_reboot;
 477        }
 478
 479        pr_info("initialized. timeout=%d sec (nowayout=%d, testmode=%i)\n",
 480                timeout, nowayout, testmode);
 481
 482        return 0;
 483
 484err_out_reboot:
 485        unregister_reboot_notifier(&wdt977_notifier);
 486err_out_region:
 487        if (!machine_is_netwinder())
 488                release_region(IO_INDEX_PORT, 2);
 489err_out:
 490        return rc;
 491}
 492
 493static void __exit wd977_exit(void)
 494{
 495        wdt977_stop();
 496        misc_deregister(&wdt977_miscdev);
 497        unregister_reboot_notifier(&wdt977_notifier);
 498        release_region(IO_INDEX_PORT, 2);
 499}
 500
 501module_init(wd977_init);
 502module_exit(wd977_exit);
 503
 504MODULE_AUTHOR("Woody Suwalski <woodys@xandros.com>");
 505MODULE_DESCRIPTION("W83977AF Watchdog driver");
 506MODULE_LICENSE("GPL");
 507