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
  34 #include <asm/uaccess.h>
  35 #include <asm/io.h>
  36
  37 #define NAME "it8712f_wdt"
  38
  39 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
  40 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
  41 MODULE_LICENSE("GPL");
  42 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
  43
  44 static int max_units = 255;
  45 static int margin = 60;         /* in seconds */
  46 module_param(margin, int, 0);
  47 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  48
  49 static int nowayout = WATCHDOG_NOWAYOUT;
  50 module_param(nowayout, int, 0);
  51 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  52
  53 static struct semaphore it8712f_wdt_sem;
  54 static unsigned expect_close;
  55 static spinlock_t io_lock;
  56 static unsigned char revision;
  57
  58 /* Dog Food address - We use the game port address */
  59 static unsigned short address;
  60
  61 #define REG             0x2e    /* The register to read/write */
  62 #define VAL             0x2f    /* The value to read/write */
  63
  64 #define LDN             0x07    /* Register: Logical device select */
  65 #define DEVID           0x20    /* Register: Device ID */
  66 #define DEVREV          0x22    /* Register: Device Revision */
  67 #define ACT_REG         0x30    /* LDN Register: Activation */
  68 #define BASE_REG        0x60    /* LDN Register: Base address */
  69
  70 #define IT8712F_DEVID   0x8712
  71
  72 #define LDN_GPIO        0x07    /* GPIO and Watch Dog Timer */
  73 #define LDN_GAME        0x09    /* Game Port */
  74
  75 #define WDT_CONTROL     0x71    /* WDT Register: Control */
  76 #define WDT_CONFIG      0x72    /* WDT Register: Configuration */
  77 #define WDT_TIMEOUT     0x73    /* WDT Register: Timeout Value */
  78
  79 #define WDT_RESET_GAME  0x10
  80 #define WDT_RESET_KBD   0x20
  81 #define WDT_RESET_MOUSE 0x40
  82 #define WDT_RESET_CIR   0x80
  83
  84 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  85
  86 #define WDT_OUT_PWROK   0x10
  87 #define WDT_OUT_KRST    0x40
  88
  89 static int
  90 superio_inb(int reg)
  91 {
  92         outb(reg, REG);
  93         return inb(VAL);
  94 }
  95
  96 static void
  97 superio_outb(int val, int reg)
  98 {
  99         outb(reg, REG);
 100         outb(val, VAL);
 101 }
 102
 103 static int
 104 superio_inw(int reg)
 105 {
 106         int val;
 107         outb(reg++, REG);
 108         val = inb(VAL) << 8;
 109         outb(reg, REG);
 110         val |= inb(VAL);
 111         return val;
 112 }
 113
 114 static inline void
 115 superio_select(int ldn)
 116 {
 117         outb(LDN, REG);
 118         outb(ldn, VAL);
 119 }
 120
 121 static inline void
 122 superio_enter(void)
 123 {
 124         spin_lock(&io_lock);
 125         outb(0x87, REG);
 126         outb(0x01, REG);
 127         outb(0x55, REG);
 128         outb(0x55, REG);
 129 }
 130
 131 static inline void
 132 superio_exit(void)
 133 {
 134         outb(0x02, REG);
 135         outb(0x02, VAL);
 136         spin_unlock(&io_lock);
 137 }
 138
 139 static inline void
 140 it8712f_wdt_ping(void)
 141 {
 142         inb(address);
 143 }
 144
 145 static void
 146 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
 169 it8712f_wdt_get_status(void)
 170 {
 171         if (superio_inb(WDT_CONTROL) & 0x01)
 172                 return WDIOF_CARDRESET;
 173         else
 174                 return 0;
 175 }
 176
 177 static void
 178 it8712f_wdt_enable(void)
 179 {
 180         printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
 181         superio_enter();
 182         superio_select(LDN_GPIO);
 183
 184         superio_outb(WDT_RESET_GAME, WDT_CONTROL);
 185
 186         it8712f_wdt_update_margin();
 187
 188         superio_exit();
 189
 190         it8712f_wdt_ping();
 191 }
 192
 193 static void
 194 it8712f_wdt_disable(void)
 195 {
 196         printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 197
 198         superio_enter();
 199         superio_select(LDN_GPIO);
 200
 201         superio_outb(0, WDT_CONFIG);
 202         superio_outb(0, WDT_CONTROL);
 203         if (revision >= 0x08)
 204                 superio_outb(0, WDT_TIMEOUT + 1);
 205         superio_outb(0, WDT_TIMEOUT);
 206
 207         superio_exit();
 208 }
 209
 210 static int
 211 it8712f_wdt_notify(struct notifier_block *this,
 212                     unsigned long code, void *unused)
 213 {
 214         if (code == SYS_HALT || code == SYS_POWER_OFF)
 215                 if (!nowayout)
 216                         it8712f_wdt_disable();
 217
 218         return NOTIFY_DONE;
 219 }
 220
 221 static struct notifier_block it8712f_wdt_notifier = {
 222         .notifier_call = it8712f_wdt_notify,
 223 };
 224
 225 static ssize_t
 226 it8712f_wdt_write(struct file *file, const char __user *data,
 227         size_t len, loff_t *ppos)
 228 {
 229         /* check for a magic close character */
 230         if (len) {
 231                 size_t i;
 232
 233                 it8712f_wdt_ping();
 234
 235                 expect_close = 0;
 236                 for (i = 0; i < len; ++i) {
 237                         char c;
 238                         if (get_user(c, data+i))
 239                                 return -EFAULT;
 240                         if (c == 'V')
 241                                 expect_close = 42;
 242                 }
 243         }
 244
 245         return len;
 246 }
 247
 248 static int
 249 it8712f_wdt_ioctl(struct inode *inode, struct file *file,
 250         unsigned int cmd, unsigned long arg)
 251 {
 252         void __user *argp = (void __user *)arg;
 253         int __user *p = argp;
 254         static struct watchdog_info ident = {
 255                 .identity = "IT8712F Watchdog",
 256                 .firmware_version = 1,
 257                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 258         };
 259         int value;
 260
 261         switch (cmd) {
 262         default:
 263                 return -ENOTTY;
 264         case WDIOC_GETSUPPORT:
 265                 if (copy_to_user(argp, &ident, sizeof(ident)))
 266                         return -EFAULT;
 267                 return 0;
 268         case WDIOC_GETSTATUS:
 269                 superio_enter();
 270                 superio_select(LDN_GPIO);
 271
 272                 value = it8712f_wdt_get_status();
 273
 274                 superio_exit();
 275
 276                 return put_user(value, p);
 277         case WDIOC_GETBOOTSTATUS:
 278                 return put_user(0, p);
 279         case WDIOC_KEEPALIVE:
 280                 it8712f_wdt_ping();
 281                 return 0;
 282         case WDIOC_SETTIMEOUT:
 283                 if (get_user(value, p))
 284                         return -EFAULT;
 285                 if (value < 1)
 286                         return -EINVAL;
 287                 if (value > (max_units * 60))
 288                         return -EINVAL;
 289                 margin = value;
 290                 superio_enter();
 291                 superio_select(LDN_GPIO);
 292
 293                 it8712f_wdt_update_margin();
 294
 295                 superio_exit();
 296                 it8712f_wdt_ping();
 297                 /* Fall through */
 298         case WDIOC_GETTIMEOUT:
 299                 if (put_user(margin, p))
 300                         return -EFAULT;
 301                 return 0;
 302         }
 303 }
 304
 305 static int
 306 it8712f_wdt_open(struct inode *inode, struct file *file)
 307 {
 308         /* only allow one at a time */
 309         if (down_trylock(&it8712f_wdt_sem))
 310                 return -EBUSY;
 311         it8712f_wdt_enable();
 312
 313         return nonseekable_open(inode, file);
 314 }
 315
 316 static int
 317 it8712f_wdt_release(struct inode *inode, struct file *file)
 318 {
 319         if (expect_close != 42) {
 320                 printk(KERN_WARNING NAME
 321                         ": watchdog device closed unexpectedly, will not"
 322                         " disable the watchdog timer\n");
 323         } else if (!nowayout) {
 324                 it8712f_wdt_disable();
 325         }
 326         expect_close = 0;
 327         up(&it8712f_wdt_sem);
 328
 329         return 0;
 330 }
 331
 332 static const struct file_operations it8712f_wdt_fops = {
 333         .owner = THIS_MODULE,
 334         .llseek = no_llseek,
 335         .write = it8712f_wdt_write,
 336         .ioctl = it8712f_wdt_ioctl,
 337         .open = it8712f_wdt_open,
 338         .release = it8712f_wdt_release,
 339 };
 340
 341 static struct miscdevice it8712f_wdt_miscdev = {
 342         .minor = WATCHDOG_MINOR,
 343         .name = "watchdog",
 344         .fops = &it8712f_wdt_fops,
 345 };
 346
 347 static int __init
 348 it8712f_wdt_find(unsigned short *address)
 349 {
 350         int err = -ENODEV;
 351         int chip_type;
 352
 353         superio_enter();
 354         chip_type = superio_inw(DEVID);
 355         if (chip_type != IT8712F_DEVID)
 356                 goto exit;
 357
 358         superio_select(LDN_GAME);
 359         superio_outb(1, ACT_REG);
 360         if (!(superio_inb(ACT_REG) & 0x01)) {
 361                 printk(KERN_ERR NAME ": Device not activated, skipping\n");
 362                 goto exit;
 363         }
 364
 365         *address = superio_inw(BASE_REG);
 366         if (*address == 0) {
 367                 printk(KERN_ERR NAME ": Base address not set, skipping\n");
 368                 goto exit;
 369         }
 370
 371         err = 0;
 372         revision = superio_inb(DEVREV) & 0x0f;
 373
 374         /* Later revisions have 16-bit values per datasheet 0.9.1 */
 375         if (revision >= 0x08)
 376                 max_units = 65535;
 377
 378         if (margin > (max_units * 60))
 379                 margin = (max_units * 60);
 380
 381         printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 382                 "using DogFood address 0x%x\n",
 383                 chip_type, revision, *address);
 384
 385 exit:
 386         superio_exit();
 387         return err;
 388 }
 389
 390 static int __init
 391 it8712f_wdt_init(void)
 392 {
 393         int err = 0;
 394
 395         spin_lock_init(&io_lock);
 396
 397         if (it8712f_wdt_find(&address))
 398                 return -ENODEV;
 399
 400         if (!request_region(address, 1, "IT8712F Watchdog")) {
 401                 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 402                 return -EBUSY;
 403         }
 404
 405         it8712f_wdt_disable();
 406
 407         sema_init(&it8712f_wdt_sem, 1);
 408
 409         err = register_reboot_notifier(&it8712f_wdt_notifier);
 410         if (err) {
 411                 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 412                 goto out;
 413         }
 414
 415         err = misc_register(&it8712f_wdt_miscdev);
 416         if (err) {
 417                 printk(KERN_ERR NAME
 418                         ": cannot register miscdev on minor=%d (err=%d)\n",
 419                         WATCHDOG_MINOR, err);
 420                 goto reboot_out;
 421         }
 422
 423         return 0;
 424
 425
 426 reboot_out:
 427         unregister_reboot_notifier(&it8712f_wdt_notifier);
 428 out:
 429         release_region(address, 1);
 430         return err;
 431 }
 432
 433 static void __exit
 434 it8712f_wdt_exit(void)
 435 {
 436         misc_deregister(&it8712f_wdt_miscdev);
 437         unregister_reboot_notifier(&it8712f_wdt_notifier);
 438         release_region(address, 1);
 439 }
 440
 441 module_init(it8712f_wdt_init);
 442 module_exit(it8712f_wdt_exit);