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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/module.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/init.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/watchdog.h>
  30 #include <linux/notifier.h>
  31 #include <linux/reboot.h>
  32 #include <linux/fs.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/io.h>
  36 #include <linux/ioport.h>
  37
  38 #define DEBUG
  39 #define NAME "it8712f_wdt"
  40
  41 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
  42 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
  43 MODULE_LICENSE("GPL");
  44 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
  45
  46 static int max_units = 255;
  47 static int margin = 60;         /* in seconds */
  48 module_param(margin, int, 0);
  49 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  50
  51 static bool nowayout = WATCHDOG_NOWAYOUT;
  52 module_param(nowayout, bool, 0);
  53 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  54
  55 static unsigned long wdt_open;
  56 static unsigned expect_close;
  57 static unsigned char revision;
  58
  59 /* Dog Food address - We use the game port address */
  60 static unsigned short address;
  61
  62 #define REG             0x2e    /* The register to read/write */
  63 #define VAL             0x2f    /* The value to read/write */
  64
  65 #define LDN             0x07    /* Register: Logical device select */
  66 #define DEVID           0x20    /* Register: Device ID */
  67 #define DEVREV          0x22    /* Register: Device Revision */
  68 #define ACT_REG         0x30    /* LDN Register: Activation */
  69 #define BASE_REG        0x60    /* LDN Register: Base address */
  70
  71 #define IT8712F_DEVID   0x8712
  72
  73 #define LDN_GPIO        0x07    /* GPIO and Watch Dog Timer */
  74 #define LDN_GAME        0x09    /* Game Port */
  75
  76 #define WDT_CONTROL     0x71    /* WDT Register: Control */
  77 #define WDT_CONFIG      0x72    /* WDT Register: Configuration */
  78 #define WDT_TIMEOUT     0x73    /* WDT Register: Timeout Value */
  79
  80 #define WDT_RESET_GAME  0x10    /* Reset timer on read or write to game port */
  81 #define WDT_RESET_KBD   0x20    /* Reset timer on keyboard interrupt */
  82 #define WDT_RESET_MOUSE 0x40    /* Reset timer on mouse interrupt */
  83 #define WDT_RESET_CIR   0x80    /* Reset timer on consumer IR interrupt */
  84
  85 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  86
  87 #define WDT_OUT_PWROK   0x10    /* Pulse PWROK on timeout */
  88 #define WDT_OUT_KRST    0x40    /* Pulse reset on timeout */
  89
  90 static int wdt_control_reg = WDT_RESET_GAME;
  91 module_param(wdt_control_reg, int, 0);
  92 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
  93                 "register. The default WDT_RESET_GAME resets the timer on "
  94                 "game port reads that this driver generates. You can also "
  95                 "use KBD, MOUSE or CIR if you have some external way to "
  96                 "generate those interrupts.");
  97
  98 static int superio_inb(int reg)
  99 {
 100         outb(reg, REG);
 101         return inb(VAL);
 102 }
 103
 104 static void superio_outb(int val, int reg)
 105 {
 106         outb(reg, REG);
 107         outb(val, VAL);
 108 }
 109
 110 static int superio_inw(int reg)
 111 {
 112         int val;
 113         outb(reg++, REG);
 114         val = inb(VAL) << 8;
 115         outb(reg, REG);
 116         val |= inb(VAL);
 117         return val;
 118 }
 119
 120 static inline void superio_select(int ldn)
 121 {
 122         outb(LDN, REG);
 123         outb(ldn, VAL);
 124 }
 125
 126 static inline int superio_enter(void)
 127 {
 128         /*
 129          * Try to reserve REG and REG + 1 for exclusive access.
 130          */
 131         if (!request_muxed_region(REG, 2, NAME))
 132                 return -EBUSY;
 133
 134         outb(0x87, REG);
 135         outb(0x01, REG);
 136         outb(0x55, REG);
 137         outb(0x55, REG);
 138         return 0;
 139 }
 140
 141 static inline void superio_exit(void)
 142 {
 143         outb(0x02, REG);
 144         outb(0x02, VAL);
 145         release_region(REG, 2);
 146 }
 147
 148 static inline void it8712f_wdt_ping(void)
 149 {
 150         if (wdt_control_reg & WDT_RESET_GAME)
 151                 inb(address);
 152 }
 153
 154 static void it8712f_wdt_update_margin(void)
 155 {
 156         int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 157         int units = margin;
 158
 159         /* Switch to minutes precision if the configured margin
 160          * value does not fit within the register width.
 161          */
 162         if (units <= max_units) {
 163                 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 164                 pr_info("timer margin %d seconds\n", units);
 165         } else {
 166                 units /= 60;
 167                 pr_info("timer margin %d minutes\n", units);
 168         }
 169         superio_outb(config, WDT_CONFIG);
 170
 171         if (revision >= 0x08)
 172                 superio_outb(units >> 8, WDT_TIMEOUT + 1);
 173         superio_outb(units, WDT_TIMEOUT);
 174 }
 175
 176 static int it8712f_wdt_get_status(void)
 177 {
 178         if (superio_inb(WDT_CONTROL) & 0x01)
 179                 return WDIOF_CARDRESET;
 180         else
 181                 return 0;
 182 }
 183
 184 static int it8712f_wdt_enable(void)
 185 {
 186         int ret = superio_enter();
 187         if (ret)
 188                 return ret;
 189
 190         pr_debug("enabling watchdog timer\n");
 191         superio_select(LDN_GPIO);
 192
 193         superio_outb(wdt_control_reg, WDT_CONTROL);
 194
 195         it8712f_wdt_update_margin();
 196
 197         superio_exit();
 198
 199         it8712f_wdt_ping();
 200
 201         return 0;
 202 }
 203
 204 static int it8712f_wdt_disable(void)
 205 {
 206         int ret = superio_enter();
 207         if (ret)
 208                 return ret;
 209
 210         pr_debug("disabling watchdog timer\n");
 211         superio_select(LDN_GPIO);
 212
 213         superio_outb(0, WDT_CONFIG);
 214         superio_outb(0, WDT_CONTROL);
 215         if (revision >= 0x08)
 216                 superio_outb(0, WDT_TIMEOUT + 1);
 217         superio_outb(0, WDT_TIMEOUT);
 218
 219         superio_exit();
 220         return 0;
 221 }
 222
 223 static int it8712f_wdt_notify(struct notifier_block *this,
 224                     unsigned long code, void *unused)
 225 {
 226         if (code == SYS_HALT || code == SYS_POWER_OFF)
 227                 if (!nowayout)
 228                         it8712f_wdt_disable();
 229
 230         return NOTIFY_DONE;
 231 }
 232
 233 static struct notifier_block it8712f_wdt_notifier = {
 234         .notifier_call = it8712f_wdt_notify,
 235 };
 236
 237 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
 238                                         size_t len, loff_t *ppos)
 239 {
 240         /* check for a magic close character */
 241         if (len) {
 242                 size_t i;
 243
 244                 it8712f_wdt_ping();
 245
 246                 expect_close = 0;
 247                 for (i = 0; i < len; ++i) {
 248                         char c;
 249                         if (get_user(c, data + i))
 250                                 return -EFAULT;
 251                         if (c == 'V')
 252                                 expect_close = 42;
 253                 }
 254         }
 255
 256         return len;
 257 }
 258
 259 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 260                                                         unsigned long arg)
 261 {
 262         void __user *argp = (void __user *)arg;
 263         int __user *p = argp;
 264         static const struct watchdog_info ident = {
 265                 .identity = "IT8712F Watchdog",
 266                 .firmware_version = 1,
 267                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 268                                                 WDIOF_MAGICCLOSE,
 269         };
 270         int value;
 271         int ret;
 272
 273         switch (cmd) {
 274         case WDIOC_GETSUPPORT:
 275                 if (copy_to_user(argp, &ident, sizeof(ident)))
 276                         return -EFAULT;
 277                 return 0;
 278         case WDIOC_GETSTATUS:
 279                 ret = superio_enter();
 280                 if (ret)
 281                         return ret;
 282                 superio_select(LDN_GPIO);
 283
 284                 value = it8712f_wdt_get_status();
 285
 286                 superio_exit();
 287
 288                 return put_user(value, p);
 289         case WDIOC_GETBOOTSTATUS:
 290                 return put_user(0, p);
 291         case WDIOC_KEEPALIVE:
 292                 it8712f_wdt_ping();
 293                 return 0;
 294         case WDIOC_SETTIMEOUT:
 295                 if (get_user(value, p))
 296                         return -EFAULT;
 297                 if (value < 1)
 298                         return -EINVAL;
 299                 if (value > (max_units * 60))
 300                         return -EINVAL;
 301                 margin = value;
 302                 ret = superio_enter();
 303                 if (ret)
 304                         return ret;
 305                 superio_select(LDN_GPIO);
 306
 307                 it8712f_wdt_update_margin();
 308
 309                 superio_exit();
 310                 it8712f_wdt_ping();
 311                 /* Fall through */
 312         case WDIOC_GETTIMEOUT:
 313                 if (put_user(margin, p))
 314                         return -EFAULT;
 315                 return 0;
 316         default:
 317                 return -ENOTTY;
 318         }
 319 }
 320
 321 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 322 {
 323         int ret;
 324         /* only allow one at a time */
 325         if (test_and_set_bit(0, &wdt_open))
 326                 return -EBUSY;
 327
 328         ret = it8712f_wdt_enable();
 329         if (ret)
 330                 return ret;
 331         return nonseekable_open(inode, file);
 332 }
 333
 334 static int it8712f_wdt_release(struct inode *inode, struct file *file)
 335 {
 336         if (expect_close != 42) {
 337                 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
 338         } else if (!nowayout) {
 339                 if (it8712f_wdt_disable())
 340                         pr_warn("Watchdog disable failed\n");
 341         }
 342         expect_close = 0;
 343         clear_bit(0, &wdt_open);
 344
 345         return 0;
 346 }
 347
 348 static const struct file_operations it8712f_wdt_fops = {
 349         .owner = THIS_MODULE,
 350         .llseek = no_llseek,
 351         .write = it8712f_wdt_write,
 352         .unlocked_ioctl = it8712f_wdt_ioctl,
 353         .open = it8712f_wdt_open,
 354         .release = it8712f_wdt_release,
 355 };
 356
 357 static struct miscdevice it8712f_wdt_miscdev = {
 358         .minor = WATCHDOG_MINOR,
 359         .name = "watchdog",
 360         .fops = &it8712f_wdt_fops,
 361 };
 362
 363 static int __init it8712f_wdt_find(unsigned short *address)
 364 {
 365         int err = -ENODEV;
 366         int chip_type;
 367         int ret = superio_enter();
 368         if (ret)
 369                 return ret;
 370
 371         chip_type = superio_inw(DEVID);
 372         if (chip_type != IT8712F_DEVID)
 373                 goto exit;
 374
 375         superio_select(LDN_GAME);
 376         superio_outb(1, ACT_REG);
 377         if (!(superio_inb(ACT_REG) & 0x01)) {
 378                 pr_err("Device not activated, skipping\n");
 379                 goto exit;
 380         }
 381
 382         *address = superio_inw(BASE_REG);
 383         if (*address == 0) {
 384                 pr_err("Base address not set, skipping\n");
 385                 goto exit;
 386         }
 387
 388         err = 0;
 389         revision = superio_inb(DEVREV) & 0x0f;
 390
 391         /* Later revisions have 16-bit values per datasheet 0.9.1 */
 392         if (revision >= 0x08)
 393                 max_units = 65535;
 394
 395         if (margin > (max_units * 60))
 396                 margin = (max_units * 60);
 397
 398         pr_info("Found IT%04xF chip revision %d - 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                 pr_warn("watchdog I/O region busy\n");
 415                 return -EBUSY;
 416         }
 417
 418         err = it8712f_wdt_disable();
 419         if (err) {
 420                 pr_err("unable to disable watchdog timer\n");
 421                 goto out;
 422         }
 423
 424         err = register_reboot_notifier(&it8712f_wdt_notifier);
 425         if (err) {
 426                 pr_err("unable to register reboot notifier\n");
 427                 goto out;
 428         }
 429
 430         err = misc_register(&it8712f_wdt_miscdev);
 431         if (err) {
 432                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 433                        WATCHDOG_MINOR, err);
 434                 goto reboot_out;
 435         }
 436
 437         return 0;
 438
 439
 440 reboot_out:
 441         unregister_reboot_notifier(&it8712f_wdt_notifier);
 442 out:
 443         release_region(address, 1);
 444         return err;
 445 }
 446
 447 static void __exit it8712f_wdt_exit(void)
 448 {
 449         misc_deregister(&it8712f_wdt_miscdev);
 450         unregister_reboot_notifier(&it8712f_wdt_notifier);
 451         release_region(address, 1);
 452 }
 453
 454 module_init(it8712f_wdt_init);
 455 module_exit(it8712f_wdt_exit);