drivers/watchdog/it8712f_wdt.c

   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
  38 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
  39 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
  40 MODULE_LICENSE("GPL");
  41 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
  42
  43 static int max_units = 255;
  44 static int margin = 60;         /* in seconds */
  45 module_param(margin, int, 0);
  46 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  47
  48 static int nowayout = WATCHDOG_NOWAYOUT;
  49 module_param(nowayout, int, 0);
  50 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  51
  52 static unsigned long wdt_open;
  53 static unsigned expect_close;
  54 static spinlock_t io_lock;
  55 static unsigned char revision;
  56
  57 /* Dog Food address - We use the game port address */
  58 static 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
  88 static int superio_inb(int reg)
  89 {
  90         outb(reg, REG);
  91         return inb(VAL);
  92 }
  93
  94 static void superio_outb(int val, int reg)
  95 {
  96         outb(reg, REG);
  97         outb(val, VAL);
  98 }
  99
 100 static 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
 110 static inline void superio_select(int ldn)
 111 {
 112         outb(LDN, REG);
 113         outb(ldn, VAL);
 114 }
 115
 116 static 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
 125 static inline void superio_exit(void)
 126 {
 127         outb(0x02, REG);
 128         outb(0x02, VAL);
 129         spin_unlock(&io_lock);
 130 }
 131
 132 static inline void it8712f_wdt_ping(void)
 133 {
 134         inb(address);
 135 }
 136
 137 static 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
 159 static 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
 167 static 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
 182 static 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
 198 static 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
 208 static struct notifier_block it8712f_wdt_notifier = {
 209         .notifier_call = it8712f_wdt_notify,
 210 };
 211
 212 static 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
 234 static 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                                                 WDIOF_MAGICCLOSE,
 244         };
 245         int value;
 246
 247         switch (cmd) {
 248         case WDIOC_GETSUPPORT:
 249                 if (copy_to_user(argp, &ident, sizeof(ident)))
 250                         return -EFAULT;
 251                 return 0;
 252         case WDIOC_GETSTATUS:
 253                 superio_enter();
 254                 superio_select(LDN_GPIO);
 255
 256                 value = it8712f_wdt_get_status();
 257
 258                 superio_exit();
 259
 260                 return put_user(value, p);
 261         case WDIOC_GETBOOTSTATUS:
 262                 return put_user(0, p);
 263         case WDIOC_KEEPALIVE:
 264                 it8712f_wdt_ping();
 265                 return 0;
 266         case WDIOC_SETTIMEOUT:
 267                 if (get_user(value, p))
 268                         return -EFAULT;
 269                 if (value < 1)
 270                         return -EINVAL;
 271                 if (value > (max_units * 60))
 272                         return -EINVAL;
 273                 margin = value;
 274                 superio_enter();
 275                 superio_select(LDN_GPIO);
 276
 277                 it8712f_wdt_update_margin();
 278
 279                 superio_exit();
 280                 it8712f_wdt_ping();
 281                 /* Fall through */
 282         case WDIOC_GETTIMEOUT:
 283                 if (put_user(margin, p))
 284                         return -EFAULT;
 285                 return 0;
 286         default:
 287                 return -ENOTTY;
 288         }
 289 }
 290
 291 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 292 {
 293         /* only allow one at a time */
 294         if (test_and_set_bit(0, &wdt_open))
 295                 return -EBUSY;
 296         it8712f_wdt_enable();
 297         return nonseekable_open(inode, file);
 298 }
 299
 300 static int it8712f_wdt_release(struct inode *inode, struct file *file)
 301 {
 302         if (expect_close != 42) {
 303                 printk(KERN_WARNING NAME
 304                         ": watchdog device closed unexpectedly, will not"
 305                         " disable the watchdog timer\n");
 306         } else if (!nowayout) {
 307                 it8712f_wdt_disable();
 308         }
 309         expect_close = 0;
 310         clear_bit(0, &wdt_open);
 311
 312         return 0;
 313 }
 314
 315 static const struct file_operations it8712f_wdt_fops = {
 316         .owner = THIS_MODULE,
 317         .llseek = no_llseek,
 318         .write = it8712f_wdt_write,
 319         .unlocked_ioctl = it8712f_wdt_ioctl,
 320         .open = it8712f_wdt_open,
 321         .release = it8712f_wdt_release,
 322 };
 323
 324 static struct miscdevice it8712f_wdt_miscdev = {
 325         .minor = WATCHDOG_MINOR,
 326         .name = "watchdog",
 327         .fops = &it8712f_wdt_fops,
 328 };
 329
 330 static int __init it8712f_wdt_find(unsigned short *address)
 331 {
 332         int err = -ENODEV;
 333         int chip_type;
 334
 335         superio_enter();
 336         chip_type = superio_inw(DEVID);
 337         if (chip_type != IT8712F_DEVID)
 338                 goto exit;
 339
 340         superio_select(LDN_GAME);
 341         superio_outb(1, ACT_REG);
 342         if (!(superio_inb(ACT_REG) & 0x01)) {
 343                 printk(KERN_ERR NAME ": Device not activated, skipping\n");
 344                 goto exit;
 345         }
 346
 347         *address = superio_inw(BASE_REG);
 348         if (*address == 0) {
 349                 printk(KERN_ERR NAME ": Base address not set, skipping\n");
 350                 goto exit;
 351         }
 352
 353         err = 0;
 354         revision = superio_inb(DEVREV) & 0x0f;
 355
 356         /* Later revisions have 16-bit values per datasheet 0.9.1 */
 357         if (revision >= 0x08)
 358                 max_units = 65535;
 359
 360         if (margin > (max_units * 60))
 361                 margin = (max_units * 60);
 362
 363         printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 364                 "using DogFood address 0x%x\n",
 365                 chip_type, revision, *address);
 366
 367 exit:
 368         superio_exit();
 369         return err;
 370 }
 371
 372 static int __init it8712f_wdt_init(void)
 373 {
 374         int err = 0;
 375
 376         spin_lock_init(&io_lock);
 377
 378         if (it8712f_wdt_find(&address))
 379                 return -ENODEV;
 380
 381         if (!request_region(address, 1, "IT8712F Watchdog")) {
 382                 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 383                 return -EBUSY;
 384         }
 385
 386         it8712f_wdt_disable();
 387
 388         err = register_reboot_notifier(&it8712f_wdt_notifier);
 389         if (err) {
 390                 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 391                 goto out;
 392         }
 393
 394         err = misc_register(&it8712f_wdt_miscdev);
 395         if (err) {
 396                 printk(KERN_ERR NAME
 397                         ": cannot register miscdev on minor=%d (err=%d)\n",
 398                         WATCHDOG_MINOR, err);
 399                 goto reboot_out;
 400         }
 401
 402         return 0;
 403
 404
 405 reboot_out:
 406         unregister_reboot_notifier(&it8712f_wdt_notifier);
 407 out:
 408         release_region(address, 1);
 409         return err;
 410 }
 411
 412 static void __exit it8712f_wdt_exit(void)
 413 {
 414         misc_deregister(&it8712f_wdt_miscdev);
 415         unregister_reboot_notifier(&it8712f_wdt_notifier);
 416         release_region(address, 1);
 417 }
 418
 419 module_init(it8712f_wdt_init);
 420 module_exit(it8712f_wdt_exit);