linux/drivers/watchdog/w83977f_wdt.c
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   1/*
   2 *      W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
   3 *
   4 *      (c) Copyright 2005  Jose Goncalves <jose.goncalves@inov.pt>
   5 *
   6 *      Based on w83877f_wdt.c by Scott Jennings,
   7 *           and wdt977.c by Woody Suwalski
   8 *
   9 *                      -----------------------
  10 *
  11 *      This program is free software; you can redistribute it and/or
  12 *      modify it under the terms of the GNU General Public License
  13 *      as published by the Free Software Foundation; either version
  14 *      2 of the License, or (at your option) any later version.
  15 *
  16 */
  17
  18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20#include <linux/module.h>
  21#include <linux/moduleparam.h>
  22#include <linux/types.h>
  23#include <linux/kernel.h>
  24#include <linux/fs.h>
  25#include <linux/miscdevice.h>
  26#include <linux/init.h>
  27#include <linux/ioport.h>
  28#include <linux/watchdog.h>
  29#include <linux/notifier.h>
  30#include <linux/reboot.h>
  31#include <linux/uaccess.h>
  32#include <linux/io.h>
  33
  34
  35#define WATCHDOG_VERSION  "1.00"
  36#define WATCHDOG_NAME     "W83977F WDT"
  37
  38#define IO_INDEX_PORT     0x3F0
  39#define IO_DATA_PORT      (IO_INDEX_PORT+1)
  40
  41#define UNLOCK_DATA       0x87
  42#define LOCK_DATA         0xAA
  43#define DEVICE_REGISTER   0x07
  44
  45#define DEFAULT_TIMEOUT   45            /* default timeout in seconds */
  46
  47static  int timeout = DEFAULT_TIMEOUT;
  48static  int timeoutW;                   /* timeout in watchdog counter units */
  49static  unsigned long timer_alive;
  50static  int testmode;
  51static  char expect_close;
  52static  DEFINE_SPINLOCK(spinlock);
  53
  54module_param(timeout, int, 0);
  55MODULE_PARM_DESC(timeout,
  56                "Watchdog timeout in seconds (15..7635), default="
  57                                __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  58module_param(testmode, int, 0);
  59MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
  60
  61static bool nowayout = WATCHDOG_NOWAYOUT;
  62module_param(nowayout, bool, 0);
  63MODULE_PARM_DESC(nowayout,
  64                "Watchdog cannot be stopped once started (default="
  65                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  66
  67/*
  68 * Start the watchdog
  69 */
  70
  71static int wdt_start(void)
  72{
  73        unsigned long flags;
  74
  75        spin_lock_irqsave(&spinlock, flags);
  76
  77        /* Unlock the SuperIO chip */
  78        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  79        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  80
  81        /*
  82         * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
  83         * F2 has the timeout in watchdog counter units.
  84         * F3 is set to enable watchdog LED blink at timeout.
  85         * F4 is used to just clear the TIMEOUT'ed state (bit 0).
  86         */
  87        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  88        outb_p(0x08, IO_DATA_PORT);
  89        outb_p(0xF2, IO_INDEX_PORT);
  90        outb_p(timeoutW, IO_DATA_PORT);
  91        outb_p(0xF3, IO_INDEX_PORT);
  92        outb_p(0x08, IO_DATA_PORT);
  93        outb_p(0xF4, IO_INDEX_PORT);
  94        outb_p(0x00, IO_DATA_PORT);
  95
  96        /* Set device Aux2 active */
  97        outb_p(0x30, IO_INDEX_PORT);
  98        outb_p(0x01, IO_DATA_PORT);
  99
 100        /*
 101         * Select device Aux1 (dev=7) to set GP16 as the watchdog output
 102         * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
 103         * Map GP16 at pin 119.
 104         * In test mode watch the bit 0 on F4 to indicate "triggered" or
 105         * check watchdog LED on SBC.
 106         */
 107        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 108        outb_p(0x07, IO_DATA_PORT);
 109        if (!testmode) {
 110                unsigned pin_map;
 111
 112                outb_p(0xE6, IO_INDEX_PORT);
 113                outb_p(0x0A, IO_DATA_PORT);
 114                outb_p(0x2C, IO_INDEX_PORT);
 115                pin_map = inb_p(IO_DATA_PORT);
 116                pin_map |= 0x10;
 117                pin_map &= ~(0x20);
 118                outb_p(0x2C, IO_INDEX_PORT);
 119                outb_p(pin_map, IO_DATA_PORT);
 120        }
 121        outb_p(0xE3, IO_INDEX_PORT);
 122        outb_p(0x08, IO_DATA_PORT);
 123
 124        /* Set device Aux1 active */
 125        outb_p(0x30, IO_INDEX_PORT);
 126        outb_p(0x01, IO_DATA_PORT);
 127
 128        /* Lock the SuperIO chip */
 129        outb_p(LOCK_DATA, IO_INDEX_PORT);
 130
 131        spin_unlock_irqrestore(&spinlock, flags);
 132
 133        pr_info("activated\n");
 134
 135        return 0;
 136}
 137
 138/*
 139 * Stop the watchdog
 140 */
 141
 142static int wdt_stop(void)
 143{
 144        unsigned long flags;
 145
 146        spin_lock_irqsave(&spinlock, flags);
 147
 148        /* Unlock the SuperIO chip */
 149        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 150        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 151
 152        /*
 153         * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
 154         * F2 is reset to its default value (watchdog timer disabled).
 155         * F3 is reset to its default state.
 156         * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
 157         */
 158        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 159        outb_p(0x08, IO_DATA_PORT);
 160        outb_p(0xF2, IO_INDEX_PORT);
 161        outb_p(0xFF, IO_DATA_PORT);
 162        outb_p(0xF3, IO_INDEX_PORT);
 163        outb_p(0x00, IO_DATA_PORT);
 164        outb_p(0xF4, IO_INDEX_PORT);
 165        outb_p(0x00, IO_DATA_PORT);
 166        outb_p(0xF2, IO_INDEX_PORT);
 167        outb_p(0x00, IO_DATA_PORT);
 168
 169        /*
 170         * Select device Aux1 (dev=7) to set GP16 (in reg E6) and
 171         * Gp13 (in reg E3) as inputs.
 172         */
 173        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 174        outb_p(0x07, IO_DATA_PORT);
 175        if (!testmode) {
 176                outb_p(0xE6, IO_INDEX_PORT);
 177                outb_p(0x01, IO_DATA_PORT);
 178        }
 179        outb_p(0xE3, IO_INDEX_PORT);
 180        outb_p(0x01, IO_DATA_PORT);
 181
 182        /* Lock the SuperIO chip */
 183        outb_p(LOCK_DATA, IO_INDEX_PORT);
 184
 185        spin_unlock_irqrestore(&spinlock, flags);
 186
 187        pr_info("shutdown\n");
 188
 189        return 0;
 190}
 191
 192/*
 193 * Send a keepalive ping to the watchdog
 194 * This is done by simply re-writing the timeout to reg. 0xF2
 195 */
 196
 197static int wdt_keepalive(void)
 198{
 199        unsigned long flags;
 200
 201        spin_lock_irqsave(&spinlock, flags);
 202
 203        /* Unlock the SuperIO chip */
 204        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 205        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 206
 207        /* Select device Aux2 (device=8) to kick watchdog reg F2 */
 208        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 209        outb_p(0x08, IO_DATA_PORT);
 210        outb_p(0xF2, IO_INDEX_PORT);
 211        outb_p(timeoutW, IO_DATA_PORT);
 212
 213        /* Lock the SuperIO chip */
 214        outb_p(LOCK_DATA, IO_INDEX_PORT);
 215
 216        spin_unlock_irqrestore(&spinlock, flags);
 217
 218        return 0;
 219}
 220
 221/*
 222 * Set the watchdog timeout value
 223 */
 224
 225static int wdt_set_timeout(int t)
 226{
 227        int tmrval;
 228
 229        /*
 230         * Convert seconds to watchdog counter time units, rounding up.
 231         * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
 232         * value. This information is supplied in the PCM-5335 manual and was
 233         * checked by me on a real board. This is a bit strange because W83977f
 234         * datasheet says counter unit is in minutes!
 235         */
 236        if (t < 15)
 237                return -EINVAL;
 238
 239        tmrval = ((t + 15) + 29) / 30;
 240
 241        if (tmrval > 255)
 242                return -EINVAL;
 243
 244        /*
 245         * timeout is the timeout in seconds,
 246         * timeoutW is the timeout in watchdog counter units.
 247         */
 248        timeoutW = tmrval;
 249        timeout = (timeoutW * 30) - 15;
 250        return 0;
 251}
 252
 253/*
 254 * Get the watchdog status
 255 */
 256
 257static int wdt_get_status(int *status)
 258{
 259        int new_status;
 260        unsigned long flags;
 261
 262        spin_lock_irqsave(&spinlock, flags);
 263
 264        /* Unlock the SuperIO chip */
 265        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 266        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 267
 268        /* Select device Aux2 (device=8) to read watchdog reg F4 */
 269        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 270        outb_p(0x08, IO_DATA_PORT);
 271        outb_p(0xF4, IO_INDEX_PORT);
 272        new_status = inb_p(IO_DATA_PORT);
 273
 274        /* Lock the SuperIO chip */
 275        outb_p(LOCK_DATA, IO_INDEX_PORT);
 276
 277        spin_unlock_irqrestore(&spinlock, flags);
 278
 279        *status = 0;
 280        if (new_status & 1)
 281                *status |= WDIOF_CARDRESET;
 282
 283        return 0;
 284}
 285
 286
 287/*
 288 *      /dev/watchdog handling
 289 */
 290
 291static int wdt_open(struct inode *inode, struct file *file)
 292{
 293        /* If the watchdog is alive we don't need to start it again */
 294        if (test_and_set_bit(0, &timer_alive))
 295                return -EBUSY;
 296
 297        if (nowayout)
 298                __module_get(THIS_MODULE);
 299
 300        wdt_start();
 301        return nonseekable_open(inode, file);
 302}
 303
 304static int wdt_release(struct inode *inode, struct file *file)
 305{
 306        /*
 307         * Shut off the timer.
 308         * Lock it in if it's a module and we set nowayout
 309         */
 310        if (expect_close == 42) {
 311                wdt_stop();
 312                clear_bit(0, &timer_alive);
 313        } else {
 314                wdt_keepalive();
 315                pr_crit("unexpected close, not stopping watchdog!\n");
 316        }
 317        expect_close = 0;
 318        return 0;
 319}
 320
 321/*
 322 *      wdt_write:
 323 *      @file: file handle to the watchdog
 324 *      @buf: buffer to write (unused as data does not matter here
 325 *      @count: count of bytes
 326 *      @ppos: pointer to the position to write. No seeks allowed
 327 *
 328 *      A write to a watchdog device is defined as a keepalive signal. Any
 329 *      write of data will do, as we we don't define content meaning.
 330 */
 331
 332static ssize_t wdt_write(struct file *file, const char __user *buf,
 333                            size_t count, loff_t *ppos)
 334{
 335        /* See if we got the magic character 'V' and reload the timer */
 336        if (count) {
 337                if (!nowayout) {
 338                        size_t ofs;
 339
 340                        /* note: just in case someone wrote the
 341                           magic character long ago */
 342                        expect_close = 0;
 343
 344                        /* scan to see whether or not we got the
 345                           magic character */
 346                        for (ofs = 0; ofs != count; ofs++) {
 347                                char c;
 348                                if (get_user(c, buf + ofs))
 349                                        return -EFAULT;
 350                                if (c == 'V')
 351                                        expect_close = 42;
 352                        }
 353                }
 354
 355                /* someone wrote to us, we should restart timer */
 356                wdt_keepalive();
 357        }
 358        return count;
 359}
 360
 361/*
 362 *      wdt_ioctl:
 363 *      @inode: inode of the device
 364 *      @file: file handle to the device
 365 *      @cmd: watchdog command
 366 *      @arg: argument pointer
 367 *
 368 *      The watchdog API defines a common set of functions for all watchdogs
 369 *      according to their available features.
 370 */
 371
 372static const struct watchdog_info ident = {
 373        .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 374        .firmware_version =     1,
 375        .identity = WATCHDOG_NAME,
 376};
 377
 378static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 379{
 380        int status;
 381        int new_options, retval = -EINVAL;
 382        int new_timeout;
 383        union {
 384                struct watchdog_info __user *ident;
 385                int __user *i;
 386        } uarg;
 387
 388        uarg.i = (int __user *)arg;
 389
 390        switch (cmd) {
 391        case WDIOC_GETSUPPORT:
 392                return copy_to_user(uarg.ident, &ident,
 393                                                sizeof(ident)) ? -EFAULT : 0;
 394
 395        case WDIOC_GETSTATUS:
 396                wdt_get_status(&status);
 397                return put_user(status, uarg.i);
 398
 399        case WDIOC_GETBOOTSTATUS:
 400                return put_user(0, uarg.i);
 401
 402        case WDIOC_SETOPTIONS:
 403                if (get_user(new_options, uarg.i))
 404                        return -EFAULT;
 405
 406                if (new_options & WDIOS_DISABLECARD) {
 407                        wdt_stop();
 408                        retval = 0;
 409                }
 410
 411                if (new_options & WDIOS_ENABLECARD) {
 412                        wdt_start();
 413                        retval = 0;
 414                }
 415
 416                return retval;
 417
 418        case WDIOC_KEEPALIVE:
 419                wdt_keepalive();
 420                return 0;
 421
 422        case WDIOC_SETTIMEOUT:
 423                if (get_user(new_timeout, uarg.i))
 424                        return -EFAULT;
 425
 426                if (wdt_set_timeout(new_timeout))
 427                        return -EINVAL;
 428
 429                wdt_keepalive();
 430                /* Fall */
 431
 432        case WDIOC_GETTIMEOUT:
 433                return put_user(timeout, uarg.i);
 434
 435        default:
 436                return -ENOTTY;
 437
 438        }
 439}
 440
 441static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 442        void *unused)
 443{
 444        if (code == SYS_DOWN || code == SYS_HALT)
 445                wdt_stop();
 446        return NOTIFY_DONE;
 447}
 448
 449static const struct file_operations wdt_fops = {
 450        .owner          = THIS_MODULE,
 451        .llseek         = no_llseek,
 452        .write          = wdt_write,
 453        .unlocked_ioctl = wdt_ioctl,
 454        .open           = wdt_open,
 455        .release        = wdt_release,
 456};
 457
 458static struct miscdevice wdt_miscdev = {
 459        .minor          = WATCHDOG_MINOR,
 460        .name           = "watchdog",
 461        .fops           = &wdt_fops,
 462};
 463
 464static struct notifier_block wdt_notifier = {
 465        .notifier_call = wdt_notify_sys,
 466};
 467
 468static int __init w83977f_wdt_init(void)
 469{
 470        int rc;
 471
 472        pr_info("driver v%s\n", WATCHDOG_VERSION);
 473
 474        /*
 475         * Check that the timeout value is within it's range;
 476         * if not reset to the default
 477         */
 478        if (wdt_set_timeout(timeout)) {
 479                wdt_set_timeout(DEFAULT_TIMEOUT);
 480                pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n",
 481                        DEFAULT_TIMEOUT);
 482        }
 483
 484        if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 485                pr_err("I/O address 0x%04x already in use\n", IO_INDEX_PORT);
 486                rc = -EIO;
 487                goto err_out;
 488        }
 489
 490        rc = register_reboot_notifier(&wdt_notifier);
 491        if (rc) {
 492                pr_err("cannot register reboot notifier (err=%d)\n", rc);
 493                goto err_out_region;
 494        }
 495
 496        rc = misc_register(&wdt_miscdev);
 497        if (rc) {
 498                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 499                       wdt_miscdev.minor, rc);
 500                goto err_out_reboot;
 501        }
 502
 503        pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 504                timeout, nowayout, testmode);
 505
 506        return 0;
 507
 508err_out_reboot:
 509        unregister_reboot_notifier(&wdt_notifier);
 510err_out_region:
 511        release_region(IO_INDEX_PORT, 2);
 512err_out:
 513        return rc;
 514}
 515
 516static void __exit w83977f_wdt_exit(void)
 517{
 518        wdt_stop();
 519        misc_deregister(&wdt_miscdev);
 520        unregister_reboot_notifier(&wdt_notifier);
 521        release_region(IO_INDEX_PORT, 2);
 522}
 523
 524module_init(w83977f_wdt_init);
 525module_exit(w83977f_wdt_exit);
 526
 527MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
 528MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
 529MODULE_LICENSE("GPL");
 530MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 531
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