linux/drivers/watchdog/eurotechwdt.c
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   1/*
   2 *      Eurotech CPU-1220/1410/1420 on board WDT driver
   3 *
   4 *      (c) Copyright 2001 Ascensit <support@ascensit.com>
   5 *      (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com>
   6 *      (c) Copyright 2002 Rob Radez <rob@osinvestor.com>
   7 *
   8 *      Based on wdt.c.
   9 *      Original copyright messages:
  10 *
  11 *      (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  12 *                                              All Rights Reserved.
  13 *
  14 *      This program is free software; you can redistribute it and/or
  15 *      modify it under the terms of the GNU General Public License
  16 *      as published by the Free Software Foundation; either version
  17 *      2 of the License, or (at your option) any later version.
  18 *
  19 *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  20 *      warranty for any of this software. This material is provided
  21 *      "AS-IS" and at no charge.
  22 *
  23 *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>*
  24 */
  25
  26/* Changelog:
  27 *
  28 * 2001 - Rodolfo Giometti
  29 *      Initial release
  30 *
  31 * 2002/04/25 - Rob Radez
  32 *      clean up #includes
  33 *      clean up locking
  34 *      make __setup param unique
  35 *      proper options in watchdog_info
  36 *      add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls
  37 *      add expect_close support
  38 *
  39 * 2002.05.30 - Joel Becker <joel.becker@oracle.com>
  40 *      Added Matt Domsch's nowayout module option.
  41 */
  42
  43/*
  44 *      The eurotech CPU-1220/1410/1420's watchdog is a part
  45 *      of the on-board SUPER I/O device SMSC FDC 37B782.
  46 */
  47
  48#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  49
  50#include <linux/interrupt.h>
  51#include <linux/module.h>
  52#include <linux/moduleparam.h>
  53#include <linux/types.h>
  54#include <linux/miscdevice.h>
  55#include <linux/watchdog.h>
  56#include <linux/fs.h>
  57#include <linux/ioport.h>
  58#include <linux/notifier.h>
  59#include <linux/reboot.h>
  60#include <linux/init.h>
  61#include <linux/io.h>
  62#include <linux/uaccess.h>
  63
  64
  65static unsigned long eurwdt_is_open;
  66static int eurwdt_timeout;
  67static char eur_expect_close;
  68static DEFINE_SPINLOCK(eurwdt_lock);
  69
  70/*
  71 * You must set these - there is no sane way to probe for this board.
  72 */
  73
  74static int io = 0x3f0;
  75static int irq = 10;
  76static char *ev = "int";
  77
  78#define WDT_TIMEOUT             60                /* 1 minute */
  79
  80static bool nowayout = WATCHDOG_NOWAYOUT;
  81module_param(nowayout, bool, 0);
  82MODULE_PARM_DESC(nowayout,
  83                "Watchdog cannot be stopped once started (default="
  84                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  85
  86/*
  87 * Some symbolic names
  88 */
  89
  90#define WDT_CTRL_REG            0x30
  91#define WDT_OUTPIN_CFG          0xe2
  92#define WDT_EVENT_INT           0x00
  93#define WDT_EVENT_REBOOT        0x08
  94#define WDT_UNIT_SEL            0xf1
  95#define WDT_UNIT_SECS           0x80
  96#define WDT_TIMEOUT_VAL         0xf2
  97#define WDT_TIMER_CFG           0xf3
  98
  99
 100module_param(io, int, 0);
 101MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
 102module_param(irq, int, 0);
 103MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
 104module_param(ev, charp, 0);
 105MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
 106
 107
 108/*
 109 * Programming support
 110 */
 111
 112static inline void eurwdt_write_reg(u8 index, u8 data)
 113{
 114        outb(index, io);
 115        outb(data, io+1);
 116}
 117
 118static inline void eurwdt_lock_chip(void)
 119{
 120        outb(0xaa, io);
 121}
 122
 123static inline void eurwdt_unlock_chip(void)
 124{
 125        outb(0x55, io);
 126        eurwdt_write_reg(0x07, 0x08);   /* set the logical device */
 127}
 128
 129static inline void eurwdt_set_timeout(int timeout)
 130{
 131        eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
 132}
 133
 134static inline void eurwdt_disable_timer(void)
 135{
 136        eurwdt_set_timeout(0);
 137}
 138
 139static void eurwdt_activate_timer(void)
 140{
 141        eurwdt_disable_timer();
 142        eurwdt_write_reg(WDT_CTRL_REG, 0x01);   /* activate the WDT */
 143        eurwdt_write_reg(WDT_OUTPIN_CFG,
 144                !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
 145
 146        /* Setting interrupt line */
 147        if (irq == 2 || irq > 15 || irq < 0) {
 148                pr_err("invalid irq number\n");
 149                irq = 0;        /* if invalid we disable interrupt */
 150        }
 151        if (irq == 0)
 152                pr_info("interrupt disabled\n");
 153
 154        eurwdt_write_reg(WDT_TIMER_CFG, irq << 4);
 155
 156        eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS);  /* we use seconds */
 157        eurwdt_set_timeout(0);  /* the default timeout */
 158}
 159
 160
 161/*
 162 * Kernel methods.
 163 */
 164
 165static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
 166{
 167        pr_crit("timeout WDT timeout\n");
 168
 169#ifdef ONLY_TESTING
 170        pr_crit("Would Reboot\n");
 171#else
 172        pr_crit("Initiating system reboot\n");
 173        emergency_restart();
 174#endif
 175        return IRQ_HANDLED;
 176}
 177
 178
 179/**
 180 * eurwdt_ping:
 181 *
 182 * Reload counter one with the watchdog timeout.
 183 */
 184
 185static void eurwdt_ping(void)
 186{
 187        /* Write the watchdog default value */
 188        eurwdt_set_timeout(eurwdt_timeout);
 189}
 190
 191/**
 192 * eurwdt_write:
 193 * @file: file handle to the watchdog
 194 * @buf: buffer to write (unused as data does not matter here
 195 * @count: count of bytes
 196 * @ppos: pointer to the position to write. No seeks allowed
 197 *
 198 * A write to a watchdog device is defined as a keepalive signal. Any
 199 * write of data will do, as we we don't define content meaning.
 200 */
 201
 202static ssize_t eurwdt_write(struct file *file, const char __user *buf,
 203size_t count, loff_t *ppos)
 204{
 205        if (count) {
 206                if (!nowayout) {
 207                        size_t i;
 208
 209                        eur_expect_close = 0;
 210
 211                        for (i = 0; i != count; i++) {
 212                                char c;
 213                                if (get_user(c, buf + i))
 214                                        return -EFAULT;
 215                                if (c == 'V')
 216                                        eur_expect_close = 42;
 217                        }
 218                }
 219                spin_lock(&eurwdt_lock);
 220                eurwdt_ping();  /* the default timeout */
 221                spin_unlock(&eurwdt_lock);
 222        }
 223        return count;
 224}
 225
 226/**
 227 * eurwdt_ioctl:
 228 * @file: file handle to the device
 229 * @cmd: watchdog command
 230 * @arg: argument pointer
 231 *
 232 * The watchdog API defines a common set of functions for all watchdogs
 233 * according to their available features.
 234 */
 235
 236static long eurwdt_ioctl(struct file *file,
 237                                        unsigned int cmd, unsigned long arg)
 238{
 239        void __user *argp = (void __user *)arg;
 240        int __user *p = argp;
 241        static const struct watchdog_info ident = {
 242                .options          = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 243                                                        | WDIOF_MAGICCLOSE,
 244                .firmware_version = 1,
 245                .identity         = "WDT Eurotech CPU-1220/1410",
 246        };
 247
 248        int time;
 249        int options, retval = -EINVAL;
 250
 251        switch (cmd) {
 252        case WDIOC_GETSUPPORT:
 253                return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 254
 255        case WDIOC_GETSTATUS:
 256        case WDIOC_GETBOOTSTATUS:
 257                return put_user(0, p);
 258
 259        case WDIOC_SETOPTIONS:
 260                if (get_user(options, p))
 261                        return -EFAULT;
 262                spin_lock(&eurwdt_lock);
 263                if (options & WDIOS_DISABLECARD) {
 264                        eurwdt_disable_timer();
 265                        retval = 0;
 266                }
 267                if (options & WDIOS_ENABLECARD) {
 268                        eurwdt_activate_timer();
 269                        eurwdt_ping();
 270                        retval = 0;
 271                }
 272                spin_unlock(&eurwdt_lock);
 273                return retval;
 274
 275        case WDIOC_KEEPALIVE:
 276                spin_lock(&eurwdt_lock);
 277                eurwdt_ping();
 278                spin_unlock(&eurwdt_lock);
 279                return 0;
 280
 281        case WDIOC_SETTIMEOUT:
 282                if (copy_from_user(&time, p, sizeof(int)))
 283                        return -EFAULT;
 284
 285                /* Sanity check */
 286                if (time < 0 || time > 255)
 287                        return -EINVAL;
 288
 289                spin_lock(&eurwdt_lock);
 290                eurwdt_timeout = time;
 291                eurwdt_set_timeout(time);
 292                spin_unlock(&eurwdt_lock);
 293                /* Fall */
 294
 295        case WDIOC_GETTIMEOUT:
 296                return put_user(eurwdt_timeout, p);
 297
 298        default:
 299                return -ENOTTY;
 300        }
 301}
 302
 303/**
 304 * eurwdt_open:
 305 * @inode: inode of device
 306 * @file: file handle to device
 307 *
 308 * The misc device has been opened. The watchdog device is single
 309 * open and on opening we load the counter.
 310 */
 311
 312static int eurwdt_open(struct inode *inode, struct file *file)
 313{
 314        if (test_and_set_bit(0, &eurwdt_is_open))
 315                return -EBUSY;
 316        eurwdt_timeout = WDT_TIMEOUT;   /* initial timeout */
 317        /* Activate the WDT */
 318        eurwdt_activate_timer();
 319        return nonseekable_open(inode, file);
 320}
 321
 322/**
 323 * eurwdt_release:
 324 * @inode: inode to board
 325 * @file: file handle to board
 326 *
 327 * The watchdog has a configurable API. There is a religious dispute
 328 * between people who want their watchdog to be able to shut down and
 329 * those who want to be sure if the watchdog manager dies the machine
 330 * reboots. In the former case we disable the counters, in the latter
 331 * case you have to open it again very soon.
 332 */
 333
 334static int eurwdt_release(struct inode *inode, struct file *file)
 335{
 336        if (eur_expect_close == 42)
 337                eurwdt_disable_timer();
 338        else {
 339                pr_crit("Unexpected close, not stopping watchdog!\n");
 340                eurwdt_ping();
 341        }
 342        clear_bit(0, &eurwdt_is_open);
 343        eur_expect_close = 0;
 344        return 0;
 345}
 346
 347/**
 348 * eurwdt_notify_sys:
 349 * @this: our notifier block
 350 * @code: the event being reported
 351 * @unused: unused
 352 *
 353 * Our notifier is called on system shutdowns. We want to turn the card
 354 * off at reboot otherwise the machine will reboot again during memory
 355 * test or worse yet during the following fsck. This would suck, in fact
 356 * trust me - if it happens it does suck.
 357 */
 358
 359static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code,
 360        void *unused)
 361{
 362        if (code == SYS_DOWN || code == SYS_HALT)
 363                eurwdt_disable_timer(); /* Turn the card off */
 364
 365        return NOTIFY_DONE;
 366}
 367
 368/*
 369 * Kernel Interfaces
 370 */
 371
 372
 373static const struct file_operations eurwdt_fops = {
 374        .owner          = THIS_MODULE,
 375        .llseek         = no_llseek,
 376        .write          = eurwdt_write,
 377        .unlocked_ioctl = eurwdt_ioctl,
 378        .open           = eurwdt_open,
 379        .release        = eurwdt_release,
 380};
 381
 382static struct miscdevice eurwdt_miscdev = {
 383        .minor  = WATCHDOG_MINOR,
 384        .name   = "watchdog",
 385        .fops   = &eurwdt_fops,
 386};
 387
 388/*
 389 * The WDT card needs to learn about soft shutdowns in order to
 390 * turn the timebomb registers off.
 391 */
 392
 393static struct notifier_block eurwdt_notifier = {
 394        .notifier_call = eurwdt_notify_sys,
 395};
 396
 397/**
 398 * cleanup_module:
 399 *
 400 * Unload the watchdog. You cannot do this with any file handles open.
 401 * If your watchdog is set to continue ticking on close and you unload
 402 * it, well it keeps ticking. We won't get the interrupt but the board
 403 * will not touch PC memory so all is fine. You just have to load a new
 404 * module in 60 seconds or reboot.
 405 */
 406
 407static void __exit eurwdt_exit(void)
 408{
 409        eurwdt_lock_chip();
 410
 411        misc_deregister(&eurwdt_miscdev);
 412
 413        unregister_reboot_notifier(&eurwdt_notifier);
 414        release_region(io, 2);
 415        free_irq(irq, NULL);
 416}
 417
 418/**
 419 * eurwdt_init:
 420 *
 421 * Set up the WDT watchdog board. After grabbing the resources
 422 * we require we need also to unlock the device.
 423 * The open() function will actually kick the board off.
 424 */
 425
 426static int __init eurwdt_init(void)
 427{
 428        int ret;
 429
 430        ret = request_irq(irq, eurwdt_interrupt, 0, "eurwdt", NULL);
 431        if (ret) {
 432                pr_err("IRQ %d is not free\n", irq);
 433                goto out;
 434        }
 435
 436        if (!request_region(io, 2, "eurwdt")) {
 437                pr_err("IO %X is not free\n", io);
 438                ret = -EBUSY;
 439                goto outirq;
 440        }
 441
 442        ret = register_reboot_notifier(&eurwdt_notifier);
 443        if (ret) {
 444                pr_err("can't register reboot notifier (err=%d)\n", ret);
 445                goto outreg;
 446        }
 447
 448        ret = misc_register(&eurwdt_miscdev);
 449        if (ret) {
 450                pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
 451                goto outreboot;
 452        }
 453
 454        eurwdt_unlock_chip();
 455
 456        ret = 0;
 457        pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n",
 458                io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
 459
 460out:
 461        return ret;
 462
 463outreboot:
 464        unregister_reboot_notifier(&eurwdt_notifier);
 465
 466outreg:
 467        release_region(io, 2);
 468
 469outirq:
 470        free_irq(irq, NULL);
 471        goto out;
 472}
 473
 474module_init(eurwdt_init);
 475module_exit(eurwdt_exit);
 476
 477MODULE_AUTHOR("Rodolfo Giometti");
 478MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
 479MODULE_LICENSE("GPL");
 480MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 481
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