linux/drivers/watchdog/it8712f_wdt.c
<<
>>
Prefs
   1/*
   2 *      IT8712F "Smart Guardian" Watchdog support
   3 *
   4 *      Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
   5 *
   6 *      Based on info and code taken from:
   7 *
   8 *      drivers/char/watchdog/scx200_wdt.c
   9 *      drivers/hwmon/it87.c
  10 *      IT8712F EC-LPC I/O Preliminary Specification 0.8.2
  11 *      IT8712F EC-LPC I/O Preliminary Specification 0.9.3
  12 *
  13 *      This program is free software; you can redistribute it and/or
  14 *      modify it under the terms of the GNU General Public License as
  15 *      published by the Free Software Foundation; either version 2 of the
  16 *      License, or (at your option) any later version.
  17 *
  18 *      The author(s) of this software shall not be held liable for damages
  19 *      of any nature resulting due to the use of this software. This
  20 *      software is provided AS-IS with no warranties.
  21 */
  22
  23#include <linux/module.h>
  24#include <linux/moduleparam.h>
  25#include <linux/init.h>
  26#include <linux/miscdevice.h>
  27#include <linux/watchdog.h>
  28#include <linux/notifier.h>
  29#include <linux/reboot.h>
  30#include <linux/fs.h>
  31#include <linux/pci.h>
  32#include <linux/spinlock.h>
  33#include <linux/uaccess.h>
  34#include <linux/io.h>
  35
  36#define NAME "it8712f_wdt"
  37
  38MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
  39MODULE_DESCRIPTION("IT8712F Watchdog Driver");
  40MODULE_LICENSE("GPL");
  41MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
  42
  43static int max_units = 255;
  44static int margin = 60;         /* in seconds */
  45module_param(margin, int, 0);
  46MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  47
  48static int nowayout = WATCHDOG_NOWAYOUT;
  49module_param(nowayout, int, 0);
  50MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  51
  52static unsigned long wdt_open;
  53static unsigned expect_close;
  54static spinlock_t io_lock;
  55static unsigned char revision;
  56
  57/* Dog Food address - We use the game port address */
  58static unsigned short address;
  59
  60#define REG             0x2e    /* The register to read/write */
  61#define VAL             0x2f    /* The value to read/write */
  62
  63#define LDN             0x07    /* Register: Logical device select */
  64#define DEVID           0x20    /* Register: Device ID */
  65#define DEVREV          0x22    /* Register: Device Revision */
  66#define ACT_REG         0x30    /* LDN Register: Activation */
  67#define BASE_REG        0x60    /* LDN Register: Base address */
  68
  69#define IT8712F_DEVID   0x8712
  70
  71#define LDN_GPIO        0x07    /* GPIO and Watch Dog Timer */
  72#define LDN_GAME        0x09    /* Game Port */
  73
  74#define WDT_CONTROL     0x71    /* WDT Register: Control */
  75#define WDT_CONFIG      0x72    /* WDT Register: Configuration */
  76#define WDT_TIMEOUT     0x73    /* WDT Register: Timeout Value */
  77
  78#define WDT_RESET_GAME  0x10
  79#define WDT_RESET_KBD   0x20
  80#define WDT_RESET_MOUSE 0x40
  81#define WDT_RESET_CIR   0x80
  82
  83#define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  84
  85#define WDT_OUT_PWROK   0x10
  86#define WDT_OUT_KRST    0x40
  87
  88static int superio_inb(int reg)
  89{
  90        outb(reg, REG);
  91        return inb(VAL);
  92}
  93
  94static void superio_outb(int val, int reg)
  95{
  96        outb(reg, REG);
  97        outb(val, VAL);
  98}
  99
 100static int superio_inw(int reg)
 101{
 102        int val;
 103        outb(reg++, REG);
 104        val = inb(VAL) << 8;
 105        outb(reg, REG);
 106        val |= inb(VAL);
 107        return val;
 108}
 109
 110static inline void superio_select(int ldn)
 111{
 112        outb(LDN, REG);
 113        outb(ldn, VAL);
 114}
 115
 116static inline void superio_enter(void)
 117{
 118        spin_lock(&io_lock);
 119        outb(0x87, REG);
 120        outb(0x01, REG);
 121        outb(0x55, REG);
 122        outb(0x55, REG);
 123}
 124
 125static inline void superio_exit(void)
 126{
 127        outb(0x02, REG);
 128        outb(0x02, VAL);
 129        spin_unlock(&io_lock);
 130}
 131
 132static inline void it8712f_wdt_ping(void)
 133{
 134        inb(address);
 135}
 136
 137static void it8712f_wdt_update_margin(void)
 138{
 139        int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 140        int units = margin;
 141
 142        /* Switch to minutes precision if the configured margin
 143         * value does not fit within the register width.
 144         */
 145        if (units <= max_units) {
 146                config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 147                printk(KERN_INFO NAME ": timer margin %d seconds\n", units);
 148        } else {
 149                units /= 60;
 150                printk(KERN_INFO NAME ": timer margin %d minutes\n", units);
 151        }
 152        superio_outb(config, WDT_CONFIG);
 153
 154        if (revision >= 0x08)
 155                superio_outb(units >> 8, WDT_TIMEOUT + 1);
 156        superio_outb(units, WDT_TIMEOUT);
 157}
 158
 159static int it8712f_wdt_get_status(void)
 160{
 161        if (superio_inb(WDT_CONTROL) & 0x01)
 162                return WDIOF_CARDRESET;
 163        else
 164                return 0;
 165}
 166
 167static void it8712f_wdt_enable(void)
 168{
 169        printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
 170        superio_enter();
 171        superio_select(LDN_GPIO);
 172
 173        superio_outb(WDT_RESET_GAME, WDT_CONTROL);
 174
 175        it8712f_wdt_update_margin();
 176
 177        superio_exit();
 178
 179        it8712f_wdt_ping();
 180}
 181
 182static void it8712f_wdt_disable(void)
 183{
 184        printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 185
 186        superio_enter();
 187        superio_select(LDN_GPIO);
 188
 189        superio_outb(0, WDT_CONFIG);
 190        superio_outb(0, WDT_CONTROL);
 191        if (revision >= 0x08)
 192                superio_outb(0, WDT_TIMEOUT + 1);
 193        superio_outb(0, WDT_TIMEOUT);
 194
 195        superio_exit();
 196}
 197
 198static int it8712f_wdt_notify(struct notifier_block *this,
 199                    unsigned long code, void *unused)
 200{
 201        if (code == SYS_HALT || code == SYS_POWER_OFF)
 202                if (!nowayout)
 203                        it8712f_wdt_disable();
 204
 205        return NOTIFY_DONE;
 206}
 207
 208static struct notifier_block it8712f_wdt_notifier = {
 209        .notifier_call = it8712f_wdt_notify,
 210};
 211
 212static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
 213                                        size_t len, loff_t *ppos)
 214{
 215        /* check for a magic close character */
 216        if (len) {
 217                size_t i;
 218
 219                it8712f_wdt_ping();
 220
 221                expect_close = 0;
 222                for (i = 0; i < len; ++i) {
 223                        char c;
 224                        if (get_user(c, data + i))
 225                                return -EFAULT;
 226                        if (c == 'V')
 227                                expect_close = 42;
 228                }
 229        }
 230
 231        return len;
 232}
 233
 234static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 235                                                        unsigned long arg)
 236{
 237        void __user *argp = (void __user *)arg;
 238        int __user *p = argp;
 239        static struct watchdog_info ident = {
 240                .identity = "IT8712F Watchdog",
 241                .firmware_version = 1,
 242                .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 243        };
 244        int value;
 245
 246        switch (cmd) {
 247        case WDIOC_GETSUPPORT:
 248                if (copy_to_user(argp, &ident, sizeof(ident)))
 249                        return -EFAULT;
 250                return 0;
 251        case WDIOC_GETSTATUS:
 252                superio_enter();
 253                superio_select(LDN_GPIO);
 254
 255                value = it8712f_wdt_get_status();
 256
 257                superio_exit();
 258
 259                return put_user(value, p);
 260        case WDIOC_GETBOOTSTATUS:
 261                return put_user(0, p);
 262        case WDIOC_KEEPALIVE:
 263                it8712f_wdt_ping();
 264                return 0;
 265        case WDIOC_SETTIMEOUT:
 266                if (get_user(value, p))
 267                        return -EFAULT;
 268                if (value < 1)
 269                        return -EINVAL;
 270                if (value > (max_units * 60))
 271                        return -EINVAL;
 272                margin = value;
 273                superio_enter();
 274                superio_select(LDN_GPIO);
 275
 276                it8712f_wdt_update_margin();
 277
 278                superio_exit();
 279                it8712f_wdt_ping();
 280                /* Fall through */
 281        case WDIOC_GETTIMEOUT:
 282                if (put_user(margin, p))
 283                        return -EFAULT;
 284                return 0;
 285        default:
 286                return -ENOTTY;
 287        }
 288}
 289
 290static int it8712f_wdt_open(struct inode *inode, struct file *file)
 291{
 292        /* only allow one at a time */
 293        if (test_and_set_bit(0, &wdt_open))
 294                return -EBUSY;
 295        it8712f_wdt_enable();
 296        return nonseekable_open(inode, file);
 297}
 298
 299static int it8712f_wdt_release(struct inode *inode, struct file *file)
 300{
 301        if (expect_close != 42) {
 302                printk(KERN_WARNING NAME
 303                        ": watchdog device closed unexpectedly, will not"
 304                        " disable the watchdog timer\n");
 305        } else if (!nowayout) {
 306                it8712f_wdt_disable();
 307        }
 308        expect_close = 0;
 309        clear_bit(0, &wdt_open);
 310
 311        return 0;
 312}
 313
 314static const struct file_operations it8712f_wdt_fops = {
 315        .owner = THIS_MODULE,
 316        .llseek = no_llseek,
 317        .write = it8712f_wdt_write,
 318        .unlocked_ioctl = it8712f_wdt_ioctl,
 319        .open = it8712f_wdt_open,
 320        .release = it8712f_wdt_release,
 321};
 322
 323static struct miscdevice it8712f_wdt_miscdev = {
 324        .minor = WATCHDOG_MINOR,
 325        .name = "watchdog",
 326        .fops = &it8712f_wdt_fops,
 327};
 328
 329static int __init it8712f_wdt_find(unsigned short *address)
 330{
 331        int err = -ENODEV;
 332        int chip_type;
 333
 334        superio_enter();
 335        chip_type = superio_inw(DEVID);
 336        if (chip_type != IT8712F_DEVID)
 337                goto exit;
 338
 339        superio_select(LDN_GAME);
 340        superio_outb(1, ACT_REG);
 341        if (!(superio_inb(ACT_REG) & 0x01)) {
 342                printk(KERN_ERR NAME ": Device not activated, skipping\n");
 343                goto exit;
 344        }
 345
 346        *address = superio_inw(BASE_REG);
 347        if (*address == 0) {
 348                printk(KERN_ERR NAME ": Base address not set, skipping\n");
 349                goto exit;
 350        }
 351
 352        err = 0;
 353        revision = superio_inb(DEVREV) & 0x0f;
 354
 355        /* Later revisions have 16-bit values per datasheet 0.9.1 */
 356        if (revision >= 0x08)
 357                max_units = 65535;
 358
 359        if (margin > (max_units * 60))
 360                margin = (max_units * 60);
 361
 362        printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 363                "using DogFood address 0x%x\n",
 364                chip_type, revision, *address);
 365
 366exit:
 367        superio_exit();
 368        return err;
 369}
 370
 371static int __init it8712f_wdt_init(void)
 372{
 373        int err = 0;
 374
 375        spin_lock_init(&io_lock);
 376
 377        if (it8712f_wdt_find(&address))
 378                return -ENODEV;
 379
 380        if (!request_region(address, 1, "IT8712F Watchdog")) {
 381                printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 382                return -EBUSY;
 383        }
 384
 385        it8712f_wdt_disable();
 386
 387        err = register_reboot_notifier(&it8712f_wdt_notifier);
 388        if (err) {
 389                printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 390                goto out;
 391        }
 392
 393        err = misc_register(&it8712f_wdt_miscdev);
 394        if (err) {
 395                printk(KERN_ERR NAME
 396                        ": cannot register miscdev on minor=%d (err=%d)\n",
 397                        WATCHDOG_MINOR, err);
 398                goto reboot_out;
 399        }
 400
 401        return 0;
 402
 403
 404reboot_out:
 405        unregister_reboot_notifier(&it8712f_wdt_notifier);
 406out:
 407        release_region(address, 1);
 408        return err;
 409}
 410
 411static void __exit it8712f_wdt_exit(void)
 412{
 413        misc_deregister(&it8712f_wdt_miscdev);
 414        unregister_reboot_notifier(&it8712f_wdt_notifier);
 415        release_region(address, 1);
 416}
 417
 418module_init(it8712f_wdt_init);
 419module_exit(it8712f_wdt_exit);
 420