LXR linux/drivers/watchdog/w83977f

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
   4 *
   5 *      (c) Copyright 2005  Jose Goncalves <jose.goncalves@inov.pt>
   6 *
   7 *      Based on w83877f_wdt.c by Scott Jennings,
   8 *           and wdt977.c by Woody Suwalski
   9 *
  10 *                      -----------------------
  11 */
  12
  13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15#include <linux/module.h>
  16#include <linux/moduleparam.h>
  17#include <linux/types.h>
  18#include <linux/kernel.h>
  19#include <linux/fs.h>
  20#include <linux/miscdevice.h>
  21#include <linux/init.h>
  22#include <linux/ioport.h>
  23#include <linux/watchdog.h>
  24#include <linux/notifier.h>
  25#include <linux/reboot.h>
  26#include <linux/uaccess.h>
  27#include <linux/io.h>
  28
  29
  30#define WATCHDOG_VERSION  "1.00"
  31#define WATCHDOG_NAME     "W83977F WDT"
  32
  33#define IO_INDEX_PORT     0x3F0
  34#define IO_DATA_PORT      (IO_INDEX_PORT+1)
  35
  36#define UNLOCK_DATA       0x87
  37#define LOCK_DATA         0xAA
  38#define DEVICE_REGISTER   0x07
  39
  40#define DEFAULT_TIMEOUT   45            /* default timeout in seconds */
  41
  42static  int timeout = DEFAULT_TIMEOUT;
  43static  int timeoutW;                   /* timeout in watchdog counter units */
  44static  unsigned long timer_alive;
  45static  int testmode;
  46static  char expect_close;
  47static  DEFINE_SPINLOCK(spinlock);
  48
  49module_param(timeout, int, 0);
  50MODULE_PARM_DESC(timeout,
  51                "Watchdog timeout in seconds (15..7635), default="
  52                                __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  53module_param(testmode, int, 0);
  54MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
  55
  56static bool nowayout = WATCHDOG_NOWAYOUT;
  57module_param(nowayout, bool, 0);
  58MODULE_PARM_DESC(nowayout,
  59                "Watchdog cannot be stopped once started (default="
  60                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  61
  62/*
  63 * Start the watchdog
  64 */
  65
  66static int wdt_start(void)
  67{
  68        unsigned long flags;
  69
  70        spin_lock_irqsave(&spinlock, flags);
  71
  72        /* Unlock the SuperIO chip */
  73        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  74        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  75
  76        /*
  77         * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
  78         * F2 has the timeout in watchdog counter units.
  79         * F3 is set to enable watchdog LED blink at timeout.
  80         * F4 is used to just clear the TIMEOUT'ed state (bit 0).
  81         */
  82        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  83        outb_p(0x08, IO_DATA_PORT);
  84        outb_p(0xF2, IO_INDEX_PORT);
  85        outb_p(timeoutW, IO_DATA_PORT);
  86        outb_p(0xF3, IO_INDEX_PORT);
  87        outb_p(0x08, IO_DATA_PORT);
  88        outb_p(0xF4, IO_INDEX_PORT);
  89        outb_p(0x00, IO_DATA_PORT);
  90
  91        /* Set device Aux2 active */
  92        outb_p(0x30, IO_INDEX_PORT);
  93        outb_p(0x01, IO_DATA_PORT);
  94
  95        /*
  96         * Select device Aux1 (dev=7) to set GP16 as the watchdog output
  97         * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
  98         * Map GP16 at pin 119.
  99         * In test mode watch the bit 0 on F4 to indicate "triggered" or
 100         * check watchdog LED on SBC.
 101         */
 102        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 103        outb_p(0x07, IO_DATA_PORT);
 104        if (!testmode) {
 105                unsigned pin_map;
 106
 107                outb_p(0xE6, IO_INDEX_PORT);
 108                outb_p(0x0A, IO_DATA_PORT);
 109                outb_p(0x2C, IO_INDEX_PORT);
 110                pin_map = inb_p(IO_DATA_PORT);
 111                pin_map |= 0x10;
 112                pin_map &= ~(0x20);
 113                outb_p(0x2C, IO_INDEX_PORT);
 114                outb_p(pin_map, IO_DATA_PORT);
 115        }
 116        outb_p(0xE3, IO_INDEX_PORT);
 117        outb_p(0x08, IO_DATA_PORT);
 118
 119        /* Set device Aux1 active */
 120        outb_p(0x30, IO_INDEX_PORT);
 121        outb_p(0x01, IO_DATA_PORT);
 122
 123        /* Lock the SuperIO chip */
 124        outb_p(LOCK_DATA, IO_INDEX_PORT);
 125
 126        spin_unlock_irqrestore(&spinlock, flags);
 127
 128        pr_info("activated\n");
 129
 130        return 0;
 131}
 132
 133/*
 134 * Stop the watchdog
 135 */
 136
 137static int wdt_stop(void)
 138{
 139        unsigned long flags;
 140
 141        spin_lock_irqsave(&spinlock, flags);
 142
 143        /* Unlock the SuperIO chip */
 144        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 145        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 146
 147        /*
 148         * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
 149         * F2 is reset to its default value (watchdog timer disabled).
 150         * F3 is reset to its default state.
 151         * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
 152         */
 153        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 154        outb_p(0x08, IO_DATA_PORT);
 155        outb_p(0xF2, IO_INDEX_PORT);
 156        outb_p(0xFF, IO_DATA_PORT);
 157        outb_p(0xF3, IO_INDEX_PORT);
 158        outb_p(0x00, IO_DATA_PORT);
 159        outb_p(0xF4, IO_INDEX_PORT);
 160        outb_p(0x00, IO_DATA_PORT);
 161        outb_p(0xF2, IO_INDEX_PORT);
 162        outb_p(0x00, IO_DATA_PORT);
 163
 164        /*
 165         * Select device Aux1 (dev=7) to set GP16 (in reg E6) and
 166         * Gp13 (in reg E3) as inputs.
 167         */
 168        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 169        outb_p(0x07, IO_DATA_PORT);
 170        if (!testmode) {
 171                outb_p(0xE6, IO_INDEX_PORT);
 172                outb_p(0x01, IO_DATA_PORT);
 173        }
 174        outb_p(0xE3, IO_INDEX_PORT);
 175        outb_p(0x01, IO_DATA_PORT);
 176
 177        /* Lock the SuperIO chip */
 178        outb_p(LOCK_DATA, IO_INDEX_PORT);
 179
 180        spin_unlock_irqrestore(&spinlock, flags);
 181
 182        pr_info("shutdown\n");
 183
 184        return 0;
 185}
 186
 187/*
 188 * Send a keepalive ping to the watchdog
 189 * This is done by simply re-writing the timeout to reg. 0xF2
 190 */
 191
 192static int wdt_keepalive(void)
 193{
 194        unsigned long flags;
 195
 196        spin_lock_irqsave(&spinlock, flags);
 197
 198        /* Unlock the SuperIO chip */
 199        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 200        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 201
 202        /* Select device Aux2 (device=8) to kick watchdog reg F2 */
 203        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 204        outb_p(0x08, IO_DATA_PORT);
 205        outb_p(0xF2, IO_INDEX_PORT);
 206        outb_p(timeoutW, IO_DATA_PORT);
 207
 208        /* Lock the SuperIO chip */
 209        outb_p(LOCK_DATA, IO_INDEX_PORT);
 210
 211        spin_unlock_irqrestore(&spinlock, flags);
 212
 213        return 0;
 214}
 215
 216/*
 217 * Set the watchdog timeout value
 218 */
 219
 220static int wdt_set_timeout(int t)
 221{
 222        unsigned int tmrval;
 223
 224        /*
 225         * Convert seconds to watchdog counter time units, rounding up.
 226         * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
 227         * value. This information is supplied in the PCM-5335 manual and was
 228         * checked by me on a real board. This is a bit strange because W83977f
 229         * datasheet says counter unit is in minutes!
 230         */
 231        if (t < 15)
 232                return -EINVAL;
 233
 234        tmrval = ((t + 15) + 29) / 30;
 235
 236        if (tmrval > 255)
 237                return -EINVAL;
 238
 239        /*
 240         * timeout is the timeout in seconds,
 241         * timeoutW is the timeout in watchdog counter units.
 242         */
 243        timeoutW = tmrval;
 244        timeout = (timeoutW * 30) - 15;
 245        return 0;
 246}
 247
 248/*
 249 * Get the watchdog status
 250 */
 251
 252static int wdt_get_status(int *status)
 253{
 254        int new_status;
 255        unsigned long flags;
 256
 257        spin_lock_irqsave(&spinlock, flags);
 258
 259        /* Unlock the SuperIO chip */
 260        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 261        outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 262
 263        /* Select device Aux2 (device=8) to read watchdog reg F4 */
 264        outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 265        outb_p(0x08, IO_DATA_PORT);
 266        outb_p(0xF4, IO_INDEX_PORT);
 267        new_status = inb_p(IO_DATA_PORT);
 268
 269        /* Lock the SuperIO chip */
 270        outb_p(LOCK_DATA, IO_INDEX_PORT);
 271
 272        spin_unlock_irqrestore(&spinlock, flags);
 273
 274        *status = 0;
 275        if (new_status & 1)
 276                *status |= WDIOF_CARDRESET;
 277
 278        return 0;
 279}
 280
 281
 282/*
 283 *      /dev/watchdog handling
 284 */
 285
 286static int wdt_open(struct inode *inode, struct file *file)
 287{
 288        /* If the watchdog is alive we don't need to start it again */
 289        if (test_and_set_bit(0, &timer_alive))
 290                return -EBUSY;
 291
 292        if (nowayout)
 293                __module_get(THIS_MODULE);
 294
 295        wdt_start();
 296        return stream_open(inode, file);
 297}
 298
 299static int wdt_release(struct inode *inode, struct file *file)
 300{
 301        /*
 302         * Shut off the timer.
 303         * Lock it in if it's a module and we set nowayout
 304         */
 305        if (expect_close == 42) {
 306                wdt_stop();
 307                clear_bit(0, &timer_alive);
 308        } else {
 309                wdt_keepalive();
 310                pr_crit("unexpected close, not stopping watchdog!\n");
 311        }
 312        expect_close = 0;
 313        return 0;
 314}
 315
 316/*
 317 *      wdt_write:
 318 *      @file: file handle to the watchdog
 319 *      @buf: buffer to write (unused as data does not matter here
 320 *      @count: count of bytes
 321 *      @ppos: pointer to the position to write. No seeks allowed
 322 *
 323 *      A write to a watchdog device is defined as a keepalive signal. Any
 324 *      write of data will do, as we we don't define content meaning.
 325 */
 326
 327static ssize_t wdt_write(struct file *file, const char __user *buf,
 328                            size_t count, loff_t *ppos)
 329{
 330        /* See if we got the magic character 'V' and reload the timer */
 331        if (count) {
 332                if (!nowayout) {
 333                        size_t ofs;
 334
 335                        /* note: just in case someone wrote the
 336                           magic character long ago */
 337                        expect_close = 0;
 338
 339                        /* scan to see whether or not we got the
 340                           magic character */
 341                        for (ofs = 0; ofs != count; ofs++) {
 342                                char c;
 343                                if (get_user(c, buf + ofs))
 344                                        return -EFAULT;
 345                                if (c == 'V')
 346                                        expect_close = 42;
 347                        }
 348                }
 349
 350                /* someone wrote to us, we should restart timer */
 351                wdt_keepalive();
 352        }
 353        return count;
 354}
 355
 356/*
 357 *      wdt_ioctl:
 358 *      @inode: inode of the device
 359 *      @file: file handle to the device
 360 *      @cmd: watchdog command
 361 *      @arg: argument pointer
 362 *
 363 *      The watchdog API defines a common set of functions for all watchdogs
 364 *      according to their available features.
 365 */
 366
 367static const struct watchdog_info ident = {
 368        .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 369        .firmware_version =     1,
 370        .identity = WATCHDOG_NAME,
 371};
 372
 373static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 374{
 375        int status;
 376        int new_options, retval = -EINVAL;
 377        int new_timeout;
 378        union {
 379                struct watchdog_info __user *ident;
 380                int __user *i;
 381        } uarg;
 382
 383        uarg.i = (int __user *)arg;
 384
 385        switch (cmd) {
 386        case WDIOC_GETSUPPORT:
 387                return copy_to_user(uarg.ident, &ident,
 388                                                sizeof(ident)) ? -EFAULT : 0;
 389
 390        case WDIOC_GETSTATUS:
 391                wdt_get_status(&status);
 392                return put_user(status, uarg.i);
 393
 394        case WDIOC_GETBOOTSTATUS:
 395                return put_user(0, uarg.i);
 396
 397        case WDIOC_SETOPTIONS:
 398                if (get_user(new_options, uarg.i))
 399                        return -EFAULT;
 400
 401                if (new_options & WDIOS_DISABLECARD) {
 402                        wdt_stop();
 403                        retval = 0;
 404                }
 405
 406                if (new_options & WDIOS_ENABLECARD) {
 407                        wdt_start();
 408                        retval = 0;
 409                }
 410
 411                return retval;
 412
 413        case WDIOC_KEEPALIVE:
 414                wdt_keepalive();
 415                return 0;
 416
 417        case WDIOC_SETTIMEOUT:
 418                if (get_user(new_timeout, uarg.i))
 419                        return -EFAULT;
 420
 421                if (wdt_set_timeout(new_timeout))
 422                        return -EINVAL;
 423
 424                wdt_keepalive();
 425                fallthrough;
 426
 427        case WDIOC_GETTIMEOUT:
 428                return put_user(timeout, uarg.i);
 429
 430        default:
 431                return -ENOTTY;
 432
 433        }
 434}
 435
 436static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 437        void *unused)
 438{
 439        if (code == SYS_DOWN || code == SYS_HALT)
 440                wdt_stop();
 441        return NOTIFY_DONE;
 442}
 443
 444static const struct file_operations wdt_fops = {
 445        .owner          = THIS_MODULE,
 446        .llseek         = no_llseek,
 447        .write          = wdt_write,
 448        .unlocked_ioctl = wdt_ioctl,
 449        .compat_ioctl   = compat_ptr_ioctl,
 450        .open           = wdt_open,
 451        .release        = wdt_release,
 452};
 453
 454static struct miscdevice wdt_miscdev = {
 455        .minor          = WATCHDOG_MINOR,
 456        .name           = "watchdog",
 457        .fops           = &wdt_fops,
 458};
 459
 460static struct notifier_block wdt_notifier = {
 461        .notifier_call = wdt_notify_sys,
 462};
 463
 464static int __init w83977f_wdt_init(void)
 465{
 466        int rc;
 467
 468        pr_info("driver v%s\n", WATCHDOG_VERSION);
 469
 470        /*
 471         * Check that the timeout value is within it's range;
 472         * if not reset to the default
 473         */
 474        if (wdt_set_timeout(timeout)) {
 475                wdt_set_timeout(DEFAULT_TIMEOUT);
 476                pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n",
 477                        DEFAULT_TIMEOUT);
 478        }
 479
 480        if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 481                pr_err("I/O address 0x%04x already in use\n", IO_INDEX_PORT);
 482                rc = -EIO;
 483                goto err_out;
 484        }
 485
 486        rc = register_reboot_notifier(&wdt_notifier);
 487        if (rc) {
 488                pr_err("cannot register reboot notifier (err=%d)\n", rc);
 489                goto err_out_region;
 490        }
 491
 492        rc = misc_register(&wdt_miscdev);
 493        if (rc) {
 494                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 495                       wdt_miscdev.minor, rc);
 496                goto err_out_reboot;
 497        }
 498
 499        pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 500                timeout, nowayout, testmode);
 501
 502        return 0;
 503
 504err_out_reboot:
 505        unregister_reboot_notifier(&wdt_notifier);
 506err_out_region:
 507        release_region(IO_INDEX_PORT, 2);
 508err_out:
 509        return rc;
 510}
 511
 512static void __exit w83977f_wdt_exit(void)
 513{
 514        wdt_stop();
 515        misc_deregister(&wdt_miscdev);
 516        unregister_reboot_notifier(&wdt_notifier);
 517        release_region(IO_INDEX_PORT, 2);
 518}
 519
 520module_init(w83977f_wdt_init);
 521module_exit(w83977f_wdt_exit);
 522
 523MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
 524MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
 525MODULE_LICENSE("GPL");
 526