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    /* Reset timer on read or write to game port */
  79 #define WDT_RESET_KBD   0x20    /* Reset timer on keyboard interrupt */
  80 #define WDT_RESET_MOUSE 0x40    /* Reset timer on mouse interrupt */
  81 #define WDT_RESET_CIR   0x80    /* Reset timer on consumer IR interrupt */
  82
  83 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  84
  85 #define WDT_OUT_PWROK   0x10    /* Pulse PWROK on timeout */
  86 #define WDT_OUT_KRST    0x40    /* Pulse reset on timeout */
  87
  88 static int wdt_control_reg = WDT_RESET_GAME;
  89 module_param(wdt_control_reg, int, 0);
  90 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
  91                 "register. The default WDT_RESET_GAME resets the timer on "
  92                 "game port reads that this driver generates. You can also "
  93                 "use KBD, MOUSE or CIR if you have some external way to "
  94                 "generate those interrupts.");
  95
  96 static int superio_inb(int reg)
  97 {
  98         outb(reg, REG);
  99         return inb(VAL);
 100 }
 101
 102 static void superio_outb(int val, int reg)
 103 {
 104         outb(reg, REG);
 105         outb(val, VAL);
 106 }
 107
 108 static int superio_inw(int reg)
 109 {
 110         int val;
 111         outb(reg++, REG);
 112         val = inb(VAL) << 8;
 113         outb(reg, REG);
 114         val |= inb(VAL);
 115         return val;
 116 }
 117
 118 static inline void superio_select(int ldn)
 119 {
 120         outb(LDN, REG);
 121         outb(ldn, VAL);
 122 }
 123
 124 static inline void superio_enter(void)
 125 {
 126         spin_lock(&io_lock);
 127         outb(0x87, REG);
 128         outb(0x01, REG);
 129         outb(0x55, REG);
 130         outb(0x55, REG);
 131 }
 132
 133 static inline void superio_exit(void)
 134 {
 135         outb(0x02, REG);
 136         outb(0x02, VAL);
 137         spin_unlock(&io_lock);
 138 }
 139
 140 static inline void it8712f_wdt_ping(void)
 141 {
 142         if (wdt_control_reg & WDT_RESET_GAME)
 143                 inb(address);
 144 }
 145
 146 static void it8712f_wdt_update_margin(void)
 147 {
 148         int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 149         int units = margin;
 150
 151         /* Switch to minutes precision if the configured margin
 152          * value does not fit within the register width.
 153          */
 154         if (units <= max_units) {
 155                 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 156                 printk(KERN_INFO NAME ": timer margin %d seconds\n", units);
 157         } else {
 158                 units /= 60;
 159                 printk(KERN_INFO NAME ": timer margin %d minutes\n", units);
 160         }
 161         superio_outb(config, WDT_CONFIG);
 162
 163         if (revision >= 0x08)
 164                 superio_outb(units >> 8, WDT_TIMEOUT + 1);
 165         superio_outb(units, WDT_TIMEOUT);
 166 }
 167
 168 static int it8712f_wdt_get_status(void)
 169 {
 170         if (superio_inb(WDT_CONTROL) & 0x01)
 171                 return WDIOF_CARDRESET;
 172         else
 173                 return 0;
 174 }
 175
 176 static void it8712f_wdt_enable(void)
 177 {
 178         printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
 179         superio_enter();
 180         superio_select(LDN_GPIO);
 181
 182         superio_outb(wdt_control_reg, WDT_CONTROL);
 183
 184         it8712f_wdt_update_margin();
 185
 186         superio_exit();
 187
 188         it8712f_wdt_ping();
 189 }
 190
 191 static void it8712f_wdt_disable(void)
 192 {
 193         printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 194
 195         superio_enter();
 196         superio_select(LDN_GPIO);
 197
 198         superio_outb(0, WDT_CONFIG);
 199         superio_outb(0, WDT_CONTROL);
 200         if (revision >= 0x08)
 201                 superio_outb(0, WDT_TIMEOUT + 1);
 202         superio_outb(0, WDT_TIMEOUT);
 203
 204         superio_exit();
 205 }
 206
 207 static int it8712f_wdt_notify(struct notifier_block *this,
 208                     unsigned long code, void *unused)
 209 {
 210         if (code == SYS_HALT || code == SYS_POWER_OFF)
 211                 if (!nowayout)
 212                         it8712f_wdt_disable();
 213
 214         return NOTIFY_DONE;
 215 }
 216
 217 static struct notifier_block it8712f_wdt_notifier = {
 218         .notifier_call = it8712f_wdt_notify,
 219 };
 220
 221 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
 222                                         size_t len, loff_t *ppos)
 223 {
 224         /* check for a magic close character */
 225         if (len) {
 226                 size_t i;
 227
 228                 it8712f_wdt_ping();
 229
 230                 expect_close = 0;
 231                 for (i = 0; i < len; ++i) {
 232                         char c;
 233                         if (get_user(c, data + i))
 234                                 return -EFAULT;
 235                         if (c == 'V')
 236                                 expect_close = 42;
 237                 }
 238         }
 239
 240         return len;
 241 }
 242
 243 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 244                                                         unsigned long arg)
 245 {
 246         void __user *argp = (void __user *)arg;
 247         int __user *p = argp;
 248         static const struct watchdog_info ident = {
 249                 .identity = "IT8712F Watchdog",
 250                 .firmware_version = 1,
 251                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 252                                                 WDIOF_MAGICCLOSE,
 253         };
 254         int value;
 255
 256         switch (cmd) {
 257         case WDIOC_GETSUPPORT:
 258                 if (copy_to_user(argp, &ident, sizeof(ident)))
 259                         return -EFAULT;
 260                 return 0;
 261         case WDIOC_GETSTATUS:
 262                 superio_enter();
 263                 superio_select(LDN_GPIO);
 264
 265                 value = it8712f_wdt_get_status();
 266
 267                 superio_exit();
 268
 269                 return put_user(value, p);
 270         case WDIOC_GETBOOTSTATUS:
 271                 return put_user(0, p);
 272         case WDIOC_KEEPALIVE:
 273                 it8712f_wdt_ping();
 274                 return 0;
 275         case WDIOC_SETTIMEOUT:
 276                 if (get_user(value, p))
 277                         return -EFAULT;
 278                 if (value < 1)
 279                         return -EINVAL;
 280                 if (value > (max_units * 60))
 281                         return -EINVAL;
 282                 margin = value;
 283                 superio_enter();
 284                 superio_select(LDN_GPIO);
 285
 286                 it8712f_wdt_update_margin();
 287
 288                 superio_exit();
 289                 it8712f_wdt_ping();
 290                 /* Fall through */
 291         case WDIOC_GETTIMEOUT:
 292                 if (put_user(margin, p))
 293                         return -EFAULT;
 294                 return 0;
 295         default:
 296                 return -ENOTTY;
 297         }
 298 }
 299
 300 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 301 {
 302         /* only allow one at a time */
 303         if (test_and_set_bit(0, &wdt_open))
 304                 return -EBUSY;
 305         it8712f_wdt_enable();
 306         return nonseekable_open(inode, file);
 307 }
 308
 309 static int it8712f_wdt_release(struct inode *inode, struct file *file)
 310 {
 311         if (expect_close != 42) {
 312                 printk(KERN_WARNING NAME
 313                         ": watchdog device closed unexpectedly, will not"
 314                         " disable the watchdog timer\n");
 315         } else if (!nowayout) {
 316                 it8712f_wdt_disable();
 317         }
 318         expect_close = 0;
 319         clear_bit(0, &wdt_open);
 320
 321         return 0;
 322 }
 323
 324 static const struct file_operations it8712f_wdt_fops = {
 325         .owner = THIS_MODULE,
 326         .llseek = no_llseek,
 327         .write = it8712f_wdt_write,
 328         .unlocked_ioctl = it8712f_wdt_ioctl,
 329         .open = it8712f_wdt_open,
 330         .release = it8712f_wdt_release,
 331 };
 332
 333 static struct miscdevice it8712f_wdt_miscdev = {
 334         .minor = WATCHDOG_MINOR,
 335         .name = "watchdog",
 336         .fops = &it8712f_wdt_fops,
 337 };
 338
 339 static int __init it8712f_wdt_find(unsigned short *address)
 340 {
 341         int err = -ENODEV;
 342         int chip_type;
 343
 344         superio_enter();
 345         chip_type = superio_inw(DEVID);
 346         if (chip_type != IT8712F_DEVID)
 347                 goto exit;
 348
 349         superio_select(LDN_GAME);
 350         superio_outb(1, ACT_REG);
 351         if (!(superio_inb(ACT_REG) & 0x01)) {
 352                 printk(KERN_ERR NAME ": Device not activated, skipping\n");
 353                 goto exit;
 354         }
 355
 356         *address = superio_inw(BASE_REG);
 357         if (*address == 0) {
 358                 printk(KERN_ERR NAME ": Base address not set, skipping\n");
 359                 goto exit;
 360         }
 361
 362         err = 0;
 363         revision = superio_inb(DEVREV) & 0x0f;
 364
 365         /* Later revisions have 16-bit values per datasheet 0.9.1 */
 366         if (revision >= 0x08)
 367                 max_units = 65535;
 368
 369         if (margin > (max_units * 60))
 370                 margin = (max_units * 60);
 371
 372         printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 373                 "using DogFood address 0x%x\n",
 374                 chip_type, revision, *address);
 375
 376 exit:
 377         superio_exit();
 378         return err;
 379 }
 380
 381 static int __init it8712f_wdt_init(void)
 382 {
 383         int err = 0;
 384
 385         spin_lock_init(&io_lock);
 386
 387         if (it8712f_wdt_find(&address))
 388                 return -ENODEV;
 389
 390         if (!request_region(address, 1, "IT8712F Watchdog")) {
 391                 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 392                 return -EBUSY;
 393         }
 394
 395         it8712f_wdt_disable();
 396
 397         err = register_reboot_notifier(&it8712f_wdt_notifier);
 398         if (err) {
 399                 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 400                 goto out;
 401         }
 402
 403         err = misc_register(&it8712f_wdt_miscdev);
 404         if (err) {
 405                 printk(KERN_ERR NAME
 406                         ": cannot register miscdev on minor=%d (err=%d)\n",
 407                         WATCHDOG_MINOR, err);
 408                 goto reboot_out;
 409         }
 410
 411         return 0;
 412
 413
 414 reboot_out:
 415         unregister_reboot_notifier(&it8712f_wdt_notifier);
 416 out:
 417         release_region(address, 1);
 418         return err;
 419 }
 420
 421 static void __exit it8712f_wdt_exit(void)
 422 {
 423         misc_deregister(&it8712f_wdt_miscdev);
 424         unregister_reboot_notifier(&it8712f_wdt_notifier);
 425         release_region(address, 1);
 426 }
 427
 428 module_init(it8712f_wdt_init);
 429 module_exit(it8712f_wdt_exit);