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/spinlock.h>
  32 #include <linux/uaccess.h>
  33 #include <linux/io.h>
  34 #include <linux/ioport.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 unsigned char revision;
  55
  56 /* Dog Food address - We use the game port address */
  57 static unsigned short address;
  58
  59 #define REG             0x2e    /* The register to read/write */
  60 #define VAL             0x2f    /* The value to read/write */
  61
  62 #define LDN             0x07    /* Register: Logical device select */
  63 #define DEVID           0x20    /* Register: Device ID */
  64 #define DEVREV          0x22    /* Register: Device Revision */
  65 #define ACT_REG         0x30    /* LDN Register: Activation */
  66 #define BASE_REG        0x60    /* LDN Register: Base address */
  67
  68 #define IT8712F_DEVID   0x8712
  69
  70 #define LDN_GPIO        0x07    /* GPIO and Watch Dog Timer */
  71 #define LDN_GAME        0x09    /* Game Port */
  72
  73 #define WDT_CONTROL     0x71    /* WDT Register: Control */
  74 #define WDT_CONFIG      0x72    /* WDT Register: Configuration */
  75 #define WDT_TIMEOUT     0x73    /* WDT Register: Timeout Value */
  76
  77 #define WDT_RESET_GAME  0x10    /* Reset timer on read or write to game port */
  78 #define WDT_RESET_KBD   0x20    /* Reset timer on keyboard interrupt */
  79 #define WDT_RESET_MOUSE 0x40    /* Reset timer on mouse interrupt */
  80 #define WDT_RESET_CIR   0x80    /* Reset timer on consumer IR interrupt */
  81
  82 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  83
  84 #define WDT_OUT_PWROK   0x10    /* Pulse PWROK on timeout */
  85 #define WDT_OUT_KRST    0x40    /* Pulse reset on timeout */
  86
  87 static int wdt_control_reg = WDT_RESET_GAME;
  88 module_param(wdt_control_reg, int, 0);
  89 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
  90                 "register. The default WDT_RESET_GAME resets the timer on "
  91                 "game port reads that this driver generates. You can also "
  92                 "use KBD, MOUSE or CIR if you have some external way to "
  93                 "generate those interrupts.");
  94
  95 static int superio_inb(int reg)
  96 {
  97         outb(reg, REG);
  98         return inb(VAL);
  99 }
 100
 101 static void superio_outb(int val, int reg)
 102 {
 103         outb(reg, REG);
 104         outb(val, VAL);
 105 }
 106
 107 static int superio_inw(int reg)
 108 {
 109         int val;
 110         outb(reg++, REG);
 111         val = inb(VAL) << 8;
 112         outb(reg, REG);
 113         val |= inb(VAL);
 114         return val;
 115 }
 116
 117 static inline void superio_select(int ldn)
 118 {
 119         outb(LDN, REG);
 120         outb(ldn, VAL);
 121 }
 122
 123 static inline int superio_enter(void)
 124 {
 125         /*
 126          * Try to reserve REG and REG + 1 for exclusive access.
 127          */
 128         if (!request_muxed_region(REG, 2, NAME))
 129                 return -EBUSY;
 130
 131         outb(0x87, REG);
 132         outb(0x01, REG);
 133         outb(0x55, REG);
 134         outb(0x55, REG);
 135         return 0;
 136 }
 137
 138 static inline void superio_exit(void)
 139 {
 140         outb(0x02, REG);
 141         outb(0x02, VAL);
 142         release_region(REG, 2);
 143 }
 144
 145 static inline void it8712f_wdt_ping(void)
 146 {
 147         if (wdt_control_reg & WDT_RESET_GAME)
 148                 inb(address);
 149 }
 150
 151 static void it8712f_wdt_update_margin(void)
 152 {
 153         int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 154         int units = margin;
 155
 156         /* Switch to minutes precision if the configured margin
 157          * value does not fit within the register width.
 158          */
 159         if (units <= max_units) {
 160                 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 161                 printk(KERN_INFO NAME ": timer margin %d seconds\n", units);
 162         } else {
 163                 units /= 60;
 164                 printk(KERN_INFO NAME ": timer margin %d minutes\n", units);
 165         }
 166         superio_outb(config, WDT_CONFIG);
 167
 168         if (revision >= 0x08)
 169                 superio_outb(units >> 8, WDT_TIMEOUT + 1);
 170         superio_outb(units, WDT_TIMEOUT);
 171 }
 172
 173 static int it8712f_wdt_get_status(void)
 174 {
 175         if (superio_inb(WDT_CONTROL) & 0x01)
 176                 return WDIOF_CARDRESET;
 177         else
 178                 return 0;
 179 }
 180
 181 static int it8712f_wdt_enable(void)
 182 {
 183         int ret = superio_enter();
 184         if (ret)
 185                 return ret;
 186
 187         printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
 188         superio_select(LDN_GPIO);
 189
 190         superio_outb(wdt_control_reg, WDT_CONTROL);
 191
 192         it8712f_wdt_update_margin();
 193
 194         superio_exit();
 195
 196         it8712f_wdt_ping();
 197
 198         return 0;
 199 }
 200
 201 static int it8712f_wdt_disable(void)
 202 {
 203         int ret = superio_enter();
 204         if (ret)
 205                 return ret;
 206
 207         printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 208         superio_select(LDN_GPIO);
 209
 210         superio_outb(0, WDT_CONFIG);
 211         superio_outb(0, WDT_CONTROL);
 212         if (revision >= 0x08)
 213                 superio_outb(0, WDT_TIMEOUT + 1);
 214         superio_outb(0, WDT_TIMEOUT);
 215
 216         superio_exit();
 217         return 0;
 218 }
 219
 220 static int it8712f_wdt_notify(struct notifier_block *this,
 221                     unsigned long code, void *unused)
 222 {
 223         if (code == SYS_HALT || code == SYS_POWER_OFF)
 224                 if (!nowayout)
 225                         it8712f_wdt_disable();
 226
 227         return NOTIFY_DONE;
 228 }
 229
 230 static struct notifier_block it8712f_wdt_notifier = {
 231         .notifier_call = it8712f_wdt_notify,
 232 };
 233
 234 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
 235                                         size_t len, loff_t *ppos)
 236 {
 237         /* check for a magic close character */
 238         if (len) {
 239                 size_t i;
 240
 241                 it8712f_wdt_ping();
 242
 243                 expect_close = 0;
 244                 for (i = 0; i < len; ++i) {
 245                         char c;
 246                         if (get_user(c, data + i))
 247                                 return -EFAULT;
 248                         if (c == 'V')
 249                                 expect_close = 42;
 250                 }
 251         }
 252
 253         return len;
 254 }
 255
 256 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 257                                                         unsigned long arg)
 258 {
 259         void __user *argp = (void __user *)arg;
 260         int __user *p = argp;
 261         static const struct watchdog_info ident = {
 262                 .identity = "IT8712F Watchdog",
 263                 .firmware_version = 1,
 264                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 265                                                 WDIOF_MAGICCLOSE,
 266         };
 267         int value;
 268         int ret;
 269
 270         switch (cmd) {
 271         case WDIOC_GETSUPPORT:
 272                 if (copy_to_user(argp, &ident, sizeof(ident)))
 273                         return -EFAULT;
 274                 return 0;
 275         case WDIOC_GETSTATUS:
 276                 ret = superio_enter();
 277                 if (ret)
 278                         return ret;
 279                 superio_select(LDN_GPIO);
 280
 281                 value = it8712f_wdt_get_status();
 282
 283                 superio_exit();
 284
 285                 return put_user(value, p);
 286         case WDIOC_GETBOOTSTATUS:
 287                 return put_user(0, p);
 288         case WDIOC_KEEPALIVE:
 289                 it8712f_wdt_ping();
 290                 return 0;
 291         case WDIOC_SETTIMEOUT:
 292                 if (get_user(value, p))
 293                         return -EFAULT;
 294                 if (value < 1)
 295                         return -EINVAL;
 296                 if (value > (max_units * 60))
 297                         return -EINVAL;
 298                 margin = value;
 299                 ret = superio_enter();
 300                 if (ret)
 301                         return ret;
 302                 superio_select(LDN_GPIO);
 303
 304                 it8712f_wdt_update_margin();
 305
 306                 superio_exit();
 307                 it8712f_wdt_ping();
 308                 /* Fall through */
 309         case WDIOC_GETTIMEOUT:
 310                 if (put_user(margin, p))
 311                         return -EFAULT;
 312                 return 0;
 313         default:
 314                 return -ENOTTY;
 315         }
 316 }
 317
 318 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 319 {
 320         int ret;
 321         /* only allow one at a time */
 322         if (test_and_set_bit(0, &wdt_open))
 323                 return -EBUSY;
 324
 325         ret = it8712f_wdt_enable();
 326         if (ret)
 327                 return ret;
 328         return nonseekable_open(inode, file);
 329 }
 330
 331 static int it8712f_wdt_release(struct inode *inode, struct file *file)
 332 {
 333         if (expect_close != 42) {
 334                 printk(KERN_WARNING NAME
 335                         ": watchdog device closed unexpectedly, will not"
 336                         " disable the watchdog timer\n");
 337         } else if (!nowayout) {
 338                 if (it8712f_wdt_disable())
 339                         printk(KERN_WARNING NAME "Watchdog disable failed\n");
 340         }
 341         expect_close = 0;
 342         clear_bit(0, &wdt_open);
 343
 344         return 0;
 345 }
 346
 347 static const struct file_operations it8712f_wdt_fops = {
 348         .owner = THIS_MODULE,
 349         .llseek = no_llseek,
 350         .write = it8712f_wdt_write,
 351         .unlocked_ioctl = it8712f_wdt_ioctl,
 352         .open = it8712f_wdt_open,
 353         .release = it8712f_wdt_release,
 354 };
 355
 356 static struct miscdevice it8712f_wdt_miscdev = {
 357         .minor = WATCHDOG_MINOR,
 358         .name = "watchdog",
 359         .fops = &it8712f_wdt_fops,
 360 };
 361
 362 static int __init it8712f_wdt_find(unsigned short *address)
 363 {
 364         int err = -ENODEV;
 365         int chip_type;
 366         int ret = superio_enter();
 367         if (ret)
 368                 return ret;
 369
 370         chip_type = superio_inw(DEVID);
 371         if (chip_type != IT8712F_DEVID)
 372                 goto exit;
 373
 374         superio_select(LDN_GAME);
 375         superio_outb(1, ACT_REG);
 376         if (!(superio_inb(ACT_REG) & 0x01)) {
 377                 printk(KERN_ERR NAME ": Device not activated, skipping\n");
 378                 goto exit;
 379         }
 380
 381         *address = superio_inw(BASE_REG);
 382         if (*address == 0) {
 383                 printk(KERN_ERR NAME ": Base address not set, skipping\n");
 384                 goto exit;
 385         }
 386
 387         err = 0;
 388         revision = superio_inb(DEVREV) & 0x0f;
 389
 390         /* Later revisions have 16-bit values per datasheet 0.9.1 */
 391         if (revision >= 0x08)
 392                 max_units = 65535;
 393
 394         if (margin > (max_units * 60))
 395                 margin = (max_units * 60);
 396
 397         printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 398                 "using DogFood address 0x%x\n",
 399                 chip_type, revision, *address);
 400
 401 exit:
 402         superio_exit();
 403         return err;
 404 }
 405
 406 static int __init it8712f_wdt_init(void)
 407 {
 408         int err = 0;
 409
 410         if (it8712f_wdt_find(&address))
 411                 return -ENODEV;
 412
 413         if (!request_region(address, 1, "IT8712F Watchdog")) {
 414                 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 415                 return -EBUSY;
 416         }
 417
 418         err = it8712f_wdt_disable();
 419         if (err) {
 420                 printk(KERN_ERR NAME ": unable to disable watchdog timer.\n");
 421                 goto out;
 422         }
 423
 424         err = register_reboot_notifier(&it8712f_wdt_notifier);
 425         if (err) {
 426                 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 427                 goto out;
 428         }
 429
 430         err = misc_register(&it8712f_wdt_miscdev);
 431         if (err) {
 432                 printk(KERN_ERR NAME
 433                         ": cannot register miscdev on minor=%d (err=%d)\n",
 434                         WATCHDOG_MINOR, err);
 435                 goto reboot_out;
 436         }
 437
 438         return 0;
 439
 440
 441 reboot_out:
 442         unregister_reboot_notifier(&it8712f_wdt_notifier);
 443 out:
 444         release_region(address, 1);
 445         return err;
 446 }
 447
 448 static void __exit it8712f_wdt_exit(void)
 449 {
 450         misc_deregister(&it8712f_wdt_miscdev);
 451         unregister_reboot_notifier(&it8712f_wdt_notifier);
 452         release_region(address, 1);
 453 }
 454
 455 module_init(it8712f_wdt_init);
 456 module_exit(it8712f_wdt_exit);