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#include <linux/module.h>
  19#include <linux/moduleparam.h>
  20#include <linux/types.h>
  21#include <linux/kernel.h>
  22#include <linux/fs.h>
  23#include <linux/miscdevice.h>
  24#include <linux/init.h>
  25#include <linux/ioport.h>
  26#include <linux/watchdog.h>
  27#include <linux/notifier.h>
  28#include <linux/reboot.h>
  29#include <linux/uaccess.h>
  30#include <linux/io.h>
  31
  32#include <asm/system.h>
  33
  34#define WATCHDOG_VERSION  "1.00"
  35#define WATCHDOG_NAME     "W83977F WDT"
  36#define PFX WATCHDOG_NAME ": "
  37#define DRIVER_VERSION    WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"
  38
  39#define IO_INDEX_PORT     0x3F0
  40#define IO_DATA_PORT      (IO_INDEX_PORT+1)
  41
  42#define UNLOCK_DATA       0x87
  43#define LOCK_DATA         0xAA
  44#define DEVICE_REGISTER   0x07
  45
  46#define DEFAULT_TIMEOUT   45            /* default timeout in seconds */
  47
  48static  int timeout = DEFAULT_TIMEOUT;
  49static  int timeoutW;                   /* timeout in watchdog counter units */
  50static  unsigned long timer_alive;
  51static  int testmode;
  52static  char expect_close;
  53static  DEFINE_SPINLOCK(spinlock);
  54
  55module_param(timeout, int, 0);
  56MODULE_PARM_DESC(timeout,
  57                "Watchdog timeout in seconds (15..7635), default="
  58                                __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  59module_param(testmode, int, 0);
  60MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
  61
  62static int nowayout = WATCHDOG_NOWAYOUT;
  63module_param(nowayout, int, 0);
  64MODULE_PARM_DESC(nowayout,
  65                "Watchdog cannot be stopped once started (default="
  66                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  67
  68/*
  69 * Start the watchdog
  70 */
  71
  72static int wdt_start(void)
  73{
  74        unsigned long flags;
  75
  76        spin_lock_irqsave(&spinlock, flags);
  77
  78        /* Unlock the SuperIO chip */
  79        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  80        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  81
  82        /*
  83         * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
  84         * F2 has the timeout in watchdog counter units.
  85         * F3 is set to enable watchdog LED blink at timeout.
  86         * F4 is used to just clear the TIMEOUT'ed state (bit 0).
  87         */
  88        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  89        outb_p(0x08, IO_DATA_PORT);
  90        outb_p(0xF2, IO_INDEX_PORT);
  91        outb_p(timeoutW, IO_DATA_PORT);
  92        outb_p(0xF3, IO_INDEX_PORT);
  93        outb_p(0x08, IO_DATA_PORT);
  94        outb_p(0xF4, IO_INDEX_PORT);
  95        outb_p(0x00, IO_DATA_PORT);
  96
  97        /* Set device Aux2 active */
  98        outb_p(0x30, IO_INDEX_PORT);
  99        outb_p(0x01, IO_DATA_PORT);
 100
 101        /*
 102         * Select device Aux1 (dev=7) to set GP16 as the watchdog output
 103         * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
 104         * Map GP16 at pin 119.
 105         * In test mode watch the bit 0 on F4 to indicate "triggered" or
 106         * check watchdog LED on SBC.
 107         */
 108        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 109        outb_p(0x07, IO_DATA_PORT);
 110        if (!testmode) {
 111                unsigned pin_map;
 112
 113                outb_p(0xE6, IO_INDEX_PORT);
 114                outb_p(0x0A, IO_DATA_PORT);
 115                outb_p(0x2C, IO_INDEX_PORT);
 116                pin_map = inb_p(IO_DATA_PORT);
 117                pin_map |= 0x10;
 118                pin_map &= ~(0x20);
 119                outb_p(0x2C, IO_INDEX_PORT);
 120                outb_p(pin_map, IO_DATA_PORT);
 121        }
 122        outb_p(0xE3, IO_INDEX_PORT);
 123        outb_p(0x08, IO_DATA_PORT);
 124
 125        /* Set device Aux1 active */
 126        outb_p(0x30, IO_INDEX_PORT);
 127        outb_p(0x01, IO_DATA_PORT);
 128
 129        /* Lock the SuperIO chip */
 130        outb_p(LOCK_DATA, IO_INDEX_PORT);
 131
 132        spin_unlock_irqrestore(&spinlock, flags);
 133
 134        printk(KERN_INFO PFX "activated.\n");
 135
 136        return 0;
 137}
 138
 139/*
 140 * Stop the watchdog
 141 */
 142
 143static int wdt_stop(void)
 144{
 145        unsigned long flags;
 146
 147        spin_lock_irqsave(&spinlock, flags);
 148
 149        /* Unlock the SuperIO chip */
 150        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 151        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 152
 153        /*
 154         * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
 155         * F2 is reset to its default value (watchdog timer disabled).
 156         * F3 is reset to its default state.
 157         * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
 158         */
 159        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 160        outb_p(0x08, IO_DATA_PORT);
 161        outb_p(0xF2, IO_INDEX_PORT);
 162        outb_p(0xFF, IO_DATA_PORT);
 163        outb_p(0xF3, IO_INDEX_PORT);
 164        outb_p(0x00, IO_DATA_PORT);
 165        outb_p(0xF4, IO_INDEX_PORT);
 166        outb_p(0x00, IO_DATA_PORT);
 167        outb_p(0xF2, IO_INDEX_PORT);
 168        outb_p(0x00, IO_DATA_PORT);
 169
 170        /*
 171         * Select device Aux1 (dev=7) to set GP16 (in reg E6) and
 172         * Gp13 (in reg E3) as inputs.
 173         */
 174        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 175        outb_p(0x07, IO_DATA_PORT);
 176        if (!testmode) {
 177                outb_p(0xE6, IO_INDEX_PORT);
 178                outb_p(0x01, IO_DATA_PORT);
 179        }
 180        outb_p(0xE3, IO_INDEX_PORT);
 181        outb_p(0x01, IO_DATA_PORT);
 182
 183        /* Lock the SuperIO chip */
 184        outb_p(LOCK_DATA, IO_INDEX_PORT);
 185
 186        spin_unlock_irqrestore(&spinlock, flags);
 187
 188        printk(KERN_INFO PFX "shutdown.\n");
 189
 190        return 0;
 191}
 192
 193/*
 194 * Send a keepalive ping to the watchdog
 195 * This is done by simply re-writing the timeout to reg. 0xF2
 196 */
 197
 198static int wdt_keepalive(void)
 199{
 200        unsigned long flags;
 201
 202        spin_lock_irqsave(&spinlock, flags);
 203
 204        /* Unlock the SuperIO chip */
 205        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 206        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 207
 208        /* Select device Aux2 (device=8) to kick watchdog reg F2 */
 209        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 210        outb_p(0x08, IO_DATA_PORT);
 211        outb_p(0xF2, IO_INDEX_PORT);
 212        outb_p(timeoutW, IO_DATA_PORT);
 213
 214        /* Lock the SuperIO chip */
 215        outb_p(LOCK_DATA, IO_INDEX_PORT);
 216
 217        spin_unlock_irqrestore(&spinlock, flags);
 218
 219        return 0;
 220}
 221
 222/*
 223 * Set the watchdog timeout value
 224 */
 225
 226static int wdt_set_timeout(int t)
 227{
 228        int tmrval;
 229
 230        /*
 231         * Convert seconds to watchdog counter time units, rounding up.
 232         * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
 233         * value. This information is supplied in the PCM-5335 manual and was
 234         * checked by me on a real board. This is a bit strange because W83977f
 235         * datasheet says counter unit is in minutes!
 236         */
 237        if (t < 15)
 238                return -EINVAL;
 239
 240        tmrval = ((t + 15) + 29) / 30;
 241
 242        if (tmrval > 255)
 243                return -EINVAL;
 244
 245        /*
 246         * timeout is the timeout in seconds,
 247         * timeoutW is the timeout in watchdog counter units.
 248         */
 249        timeoutW = tmrval;
 250        timeout = (timeoutW * 30) - 15;
 251        return 0;
 252}
 253
 254/*
 255 * Get the watchdog status
 256 */
 257
 258static int wdt_get_status(int *status)
 259{
 260        int new_status;
 261        unsigned long flags;
 262
 263        spin_lock_irqsave(&spinlock, flags);
 264
 265        /* Unlock the SuperIO chip */
 266        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 267        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 268
 269        /* Select device Aux2 (device=8) to read watchdog reg F4 */
 270        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 271        outb_p(0x08, IO_DATA_PORT);
 272        outb_p(0xF4, IO_INDEX_PORT);
 273        new_status = inb_p(IO_DATA_PORT);
 274
 275        /* Lock the SuperIO chip */
 276        outb_p(LOCK_DATA, IO_INDEX_PORT);
 277
 278        spin_unlock_irqrestore(&spinlock, flags);
 279
 280        *status = 0;
 281        if (new_status & 1)
 282                *status |= WDIOF_CARDRESET;
 283
 284        return 0;
 285}
 286
 287
 288/*
 289 *      /dev/watchdog handling
 290 */
 291
 292static int wdt_open(struct inode *inode, struct file *file)
 293{
 294        /* If the watchdog is alive we don't need to start it again */
 295        if (test_and_set_bit(0, &timer_alive))
 296                return -EBUSY;
 297
 298        if (nowayout)
 299                __module_get(THIS_MODULE);
 300
 301        wdt_start();
 302        return nonseekable_open(inode, file);
 303}
 304
 305static int wdt_release(struct inode *inode, struct file *file)
 306{
 307        /*
 308         * Shut off the timer.
 309         * Lock it in if it's a module and we set nowayout
 310         */
 311        if (expect_close == 42) {
 312                wdt_stop();
 313                clear_bit(0, &timer_alive);
 314        } else {
 315                wdt_keepalive();
 316                printk(KERN_CRIT PFX
 317                        "unexpected close, not stopping watchdog!\n");
 318        }
 319        expect_close = 0;
 320        return 0;
 321}
 322
 323/*
 324 *      wdt_write:
 325 *      @file: file handle to the watchdog
 326 *      @buf: buffer to write (unused as data does not matter here
 327 *      @count: count of bytes
 328 *      @ppos: pointer to the position to write. No seeks allowed
 329 *
 330 *      A write to a watchdog device is defined as a keepalive signal. Any
 331 *      write of data will do, as we we don't define content meaning.
 332 */
 333
 334static ssize_t wdt_write(struct file *file, const char __user *buf,
 335                            size_t count, loff_t *ppos)
 336{
 337        /* See if we got the magic character 'V' and reload the timer */
 338        if (count) {
 339                if (!nowayout) {
 340                        size_t ofs;
 341
 342                        /* note: just in case someone wrote the
 343                           magic character long ago */
 344                        expect_close = 0;
 345
 346                        /* scan to see whether or not we got the
 347                           magic character */
 348                        for (ofs = 0; ofs != count; ofs++) {
 349                                char c;
 350                                if (get_user(c, buf + ofs))
 351                                        return -EFAULT;
 352                                if (c == 'V')
 353                                        expect_close = 42;
 354                        }
 355                }
 356
 357                /* someone wrote to us, we should restart timer */
 358                wdt_keepalive();
 359        }
 360        return count;
 361}
 362
 363/*
 364 *      wdt_ioctl:
 365 *      @inode: inode of the device
 366 *      @file: file handle to the device
 367 *      @cmd: watchdog command
 368 *      @arg: argument pointer
 369 *
 370 *      The watchdog API defines a common set of functions for all watchdogs
 371 *      according to their available features.
 372 */
 373
 374static struct watchdog_info ident = {
 375        .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 376        .firmware_version =     1,
 377        .identity = WATCHDOG_NAME,
 378};
 379
 380static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 381{
 382        int status;
 383        int new_options, retval = -EINVAL;
 384        int new_timeout;
 385        union {
 386                struct watchdog_info __user *ident;
 387                int __user *i;
 388        } uarg;
 389
 390        uarg.i = (int __user *)arg;
 391
 392        switch (cmd) {
 393        case WDIOC_GETSUPPORT:
 394                return copy_to_user(uarg.ident, &ident,
 395                                                sizeof(ident)) ? -EFAULT : 0;
 396
 397        case WDIOC_GETSTATUS:
 398                wdt_get_status(&status);
 399                return put_user(status, uarg.i);
 400
 401        case WDIOC_GETBOOTSTATUS:
 402                return put_user(0, uarg.i);
 403
 404        case WDIOC_SETOPTIONS:
 405                if (get_user(new_options, uarg.i))
 406                        return -EFAULT;
 407
 408                if (new_options & WDIOS_DISABLECARD) {
 409                        wdt_stop();
 410                        retval = 0;
 411                }
 412
 413                if (new_options & WDIOS_ENABLECARD) {
 414                        wdt_start();
 415                        retval = 0;
 416                }
 417
 418                return retval;
 419
 420        case WDIOC_KEEPALIVE:
 421                wdt_keepalive();
 422                return 0;
 423
 424        case WDIOC_SETTIMEOUT:
 425                if (get_user(new_timeout, uarg.i))
 426                        return -EFAULT;
 427
 428                if (wdt_set_timeout(new_timeout))
 429                    return -EINVAL;
 430
 431                wdt_keepalive();
 432                /* Fall */
 433
 434        case WDIOC_GETTIMEOUT:
 435                return put_user(timeout, uarg.i);
 436
 437        default:
 438                return -ENOTTY;
 439
 440        }
 441}
 442
 443static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 444        void *unused)
 445{
 446        if (code == SYS_DOWN || code == SYS_HALT)
 447                wdt_stop();
 448        return NOTIFY_DONE;
 449}
 450
 451static const struct file_operations wdt_fops = {
 452        .owner          = THIS_MODULE,
 453        .llseek         = no_llseek,
 454        .write          = wdt_write,
 455        .unlocked_ioctl = wdt_ioctl,
 456        .open           = wdt_open,
 457        .release        = wdt_release,
 458};
 459
 460static struct miscdevice wdt_miscdev = {
 461        .minor          = WATCHDOG_MINOR,
 462        .name           = "watchdog",
 463        .fops           = &wdt_fops,
 464};
 465
 466static struct notifier_block wdt_notifier = {
 467        .notifier_call = wdt_notify_sys,
 468};
 469
 470static int __init w83977f_wdt_init(void)
 471{
 472        int rc;
 473
 474        printk(KERN_INFO PFX DRIVER_VERSION);
 475
 476        /*
 477         * Check that the timeout value is within it's range;
 478         * if not reset to the default
 479         */
 480        if (wdt_set_timeout(timeout)) {
 481                wdt_set_timeout(DEFAULT_TIMEOUT);
 482                printk(KERN_INFO PFX
 483                    "timeout value must be 15 <= timeout <= 7635, using %d\n",
 484                                                        DEFAULT_TIMEOUT);
 485        }
 486
 487        if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 488                printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 489                        IO_INDEX_PORT);
 490                rc = -EIO;
 491                goto err_out;
 492        }
 493
 494        rc = register_reboot_notifier(&wdt_notifier);
 495        if (rc) {
 496                printk(KERN_ERR PFX
 497                        "cannot register reboot notifier (err=%d)\n", rc);
 498                goto err_out_region;
 499        }
 500
 501        rc = misc_register(&wdt_miscdev);
 502        if (rc) {
 503                printk(KERN_ERR PFX
 504                        "cannot register miscdev on minor=%d (err=%d)\n",
 505                                                wdt_miscdev.minor, rc);
 506                goto err_out_reboot;
 507        }
 508
 509        printk(KERN_INFO PFX
 510                "initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 511                                        timeout, nowayout, testmode);
 512
 513        return 0;
 514
 515err_out_reboot:
 516        unregister_reboot_notifier(&wdt_notifier);
 517err_out_region:
 518        release_region(IO_INDEX_PORT, 2);
 519err_out:
 520        return rc;
 521}
 522
 523static void __exit w83977f_wdt_exit(void)
 524{
 525        wdt_stop();
 526        misc_deregister(&wdt_miscdev);
 527        unregister_reboot_notifier(&wdt_notifier);
 528        release_region(IO_INDEX_PORT, 2);
 529}
 530
 531module_init(w83977f_wdt_init);
 532module_exit(w83977f_wdt_exit);
 533
 534MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
 535MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
 536MODULE_LICENSE("GPL");
 537MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 538