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
  45 static int max_units = 255;
  46 static int margin = 60;         /* in seconds */
  47 module_param(margin, int, 0);
  48 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  49
  50 static bool nowayout = WATCHDOG_NOWAYOUT;
  51 module_param(nowayout, bool, 0);
  52 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  53
  54 static unsigned long wdt_open;
  55 static unsigned expect_close;
  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    /* Reset timer on read or write to game port */
  80 #define WDT_RESET_KBD   0x20    /* Reset timer on keyboard interrupt */
  81 #define WDT_RESET_MOUSE 0x40    /* Reset timer on mouse interrupt */
  82 #define WDT_RESET_CIR   0x80    /* Reset timer on consumer IR interrupt */
  83
  84 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  85
  86 #define WDT_OUT_PWROK   0x10    /* Pulse PWROK on timeout */
  87 #define WDT_OUT_KRST    0x40    /* Pulse reset on timeout */
  88
  89 static int wdt_control_reg = WDT_RESET_GAME;
  90 module_param(wdt_control_reg, int, 0);
  91 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
  92                 "register. The default WDT_RESET_GAME resets the timer on "
  93                 "game port reads that this driver generates. You can also "
  94                 "use KBD, MOUSE or CIR if you have some external way to "
  95                 "generate those interrupts.");
  96
  97 static int superio_inb(int reg)
  98 {
  99         outb(reg, REG);
 100         return inb(VAL);
 101 }
 102
 103 static void superio_outb(int val, int reg)
 104 {
 105         outb(reg, REG);
 106         outb(val, VAL);
 107 }
 108
 109 static int superio_inw(int reg)
 110 {
 111         int val;
 112         outb(reg++, REG);
 113         val = inb(VAL) << 8;
 114         outb(reg, REG);
 115         val |= inb(VAL);
 116         return val;
 117 }
 118
 119 static inline void superio_select(int ldn)
 120 {
 121         outb(LDN, REG);
 122         outb(ldn, VAL);
 123 }
 124
 125 static inline int superio_enter(void)
 126 {
 127         /*
 128          * Try to reserve REG and REG + 1 for exclusive access.
 129          */
 130         if (!request_muxed_region(REG, 2, NAME))
 131                 return -EBUSY;
 132
 133         outb(0x87, REG);
 134         outb(0x01, REG);
 135         outb(0x55, REG);
 136         outb(0x55, REG);
 137         return 0;
 138 }
 139
 140 static inline void superio_exit(void)
 141 {
 142         outb(0x02, REG);
 143         outb(0x02, VAL);
 144         release_region(REG, 2);
 145 }
 146
 147 static inline void it8712f_wdt_ping(void)
 148 {
 149         if (wdt_control_reg & WDT_RESET_GAME)
 150                 inb(address);
 151 }
 152
 153 static void it8712f_wdt_update_margin(void)
 154 {
 155         int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 156         int units = margin;
 157
 158         /* Switch to minutes precision if the configured margin
 159          * value does not fit within the register width.
 160          */
 161         if (units <= max_units) {
 162                 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 163                 pr_info("timer margin %d seconds\n", units);
 164         } else {
 165                 units /= 60;
 166                 pr_info("timer margin %d minutes\n", units);
 167         }
 168         superio_outb(config, WDT_CONFIG);
 169
 170         if (revision >= 0x08)
 171                 superio_outb(units >> 8, WDT_TIMEOUT + 1);
 172         superio_outb(units, WDT_TIMEOUT);
 173 }
 174
 175 static int it8712f_wdt_get_status(void)
 176 {
 177         if (superio_inb(WDT_CONTROL) & 0x01)
 178                 return WDIOF_CARDRESET;
 179         else
 180                 return 0;
 181 }
 182
 183 static int it8712f_wdt_enable(void)
 184 {
 185         int ret = superio_enter();
 186         if (ret)
 187                 return ret;
 188
 189         pr_debug("enabling watchdog timer\n");
 190         superio_select(LDN_GPIO);
 191
 192         superio_outb(wdt_control_reg, WDT_CONTROL);
 193
 194         it8712f_wdt_update_margin();
 195
 196         superio_exit();
 197
 198         it8712f_wdt_ping();
 199
 200         return 0;
 201 }
 202
 203 static int it8712f_wdt_disable(void)
 204 {
 205         int ret = superio_enter();
 206         if (ret)
 207                 return ret;
 208
 209         pr_debug("disabling watchdog timer\n");
 210         superio_select(LDN_GPIO);
 211
 212         superio_outb(0, WDT_CONFIG);
 213         superio_outb(0, WDT_CONTROL);
 214         if (revision >= 0x08)
 215                 superio_outb(0, WDT_TIMEOUT + 1);
 216         superio_outb(0, WDT_TIMEOUT);
 217
 218         superio_exit();
 219         return 0;
 220 }
 221
 222 static int it8712f_wdt_notify(struct notifier_block *this,
 223                     unsigned long code, void *unused)
 224 {
 225         if (code == SYS_HALT || code == SYS_POWER_OFF)
 226                 if (!nowayout)
 227                         it8712f_wdt_disable();
 228
 229         return NOTIFY_DONE;
 230 }
 231
 232 static struct notifier_block it8712f_wdt_notifier = {
 233         .notifier_call = it8712f_wdt_notify,
 234 };
 235
 236 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
 237                                         size_t len, loff_t *ppos)
 238 {
 239         /* check for a magic close character */
 240         if (len) {
 241                 size_t i;
 242
 243                 it8712f_wdt_ping();
 244
 245                 expect_close = 0;
 246                 for (i = 0; i < len; ++i) {
 247                         char c;
 248                         if (get_user(c, data + i))
 249                                 return -EFAULT;
 250                         if (c == 'V')
 251                                 expect_close = 42;
 252                 }
 253         }
 254
 255         return len;
 256 }
 257
 258 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 259                                                         unsigned long arg)
 260 {
 261         void __user *argp = (void __user *)arg;
 262         int __user *p = argp;
 263         static const struct watchdog_info ident = {
 264                 .identity = "IT8712F Watchdog",
 265                 .firmware_version = 1,
 266                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 267                                                 WDIOF_MAGICCLOSE,
 268         };
 269         int value;
 270         int ret;
 271
 272         switch (cmd) {
 273         case WDIOC_GETSUPPORT:
 274                 if (copy_to_user(argp, &ident, sizeof(ident)))
 275                         return -EFAULT;
 276                 return 0;
 277         case WDIOC_GETSTATUS:
 278                 ret = superio_enter();
 279                 if (ret)
 280                         return ret;
 281                 superio_select(LDN_GPIO);
 282
 283                 value = it8712f_wdt_get_status();
 284
 285                 superio_exit();
 286
 287                 return put_user(value, p);
 288         case WDIOC_GETBOOTSTATUS:
 289                 return put_user(0, p);
 290         case WDIOC_KEEPALIVE:
 291                 it8712f_wdt_ping();
 292                 return 0;
 293         case WDIOC_SETTIMEOUT:
 294                 if (get_user(value, p))
 295                         return -EFAULT;
 296                 if (value < 1)
 297                         return -EINVAL;
 298                 if (value > (max_units * 60))
 299                         return -EINVAL;
 300                 margin = value;
 301                 ret = superio_enter();
 302                 if (ret)
 303                         return ret;
 304                 superio_select(LDN_GPIO);
 305
 306                 it8712f_wdt_update_margin();
 307
 308                 superio_exit();
 309                 it8712f_wdt_ping();
 310                 /* Fall through */
 311         case WDIOC_GETTIMEOUT:
 312                 if (put_user(margin, p))
 313                         return -EFAULT;
 314                 return 0;
 315         default:
 316                 return -ENOTTY;
 317         }
 318 }
 319
 320 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 321 {
 322         int ret;
 323         /* only allow one at a time */
 324         if (test_and_set_bit(0, &wdt_open))
 325                 return -EBUSY;
 326
 327         ret = it8712f_wdt_enable();
 328         if (ret)
 329                 return ret;
 330         return nonseekable_open(inode, file);
 331 }
 332
 333 static int it8712f_wdt_release(struct inode *inode, struct file *file)
 334 {
 335         if (expect_close != 42) {
 336                 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
 337         } else if (!nowayout) {
 338                 if (it8712f_wdt_disable())
 339                         pr_warn("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                 pr_err("Device not activated, skipping\n");
 378                 goto exit;
 379         }
 380
 381         *address = superio_inw(BASE_REG);
 382         if (*address == 0) {
 383                 pr_err("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         pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
 398                 chip_type, revision, *address);
 399
 400 exit:
 401         superio_exit();
 402         return err;
 403 }
 404
 405 static int __init it8712f_wdt_init(void)
 406 {
 407         int err = 0;
 408
 409         if (it8712f_wdt_find(&address))
 410                 return -ENODEV;
 411
 412         if (!request_region(address, 1, "IT8712F Watchdog")) {
 413                 pr_warn("watchdog I/O region busy\n");
 414                 return -EBUSY;
 415         }
 416
 417         err = it8712f_wdt_disable();
 418         if (err) {
 419                 pr_err("unable to disable watchdog timer\n");
 420                 goto out;
 421         }
 422
 423         err = register_reboot_notifier(&it8712f_wdt_notifier);
 424         if (err) {
 425                 pr_err("unable to register reboot notifier\n");
 426                 goto out;
 427         }
 428
 429         err = misc_register(&it8712f_wdt_miscdev);
 430         if (err) {
 431                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 432                        WATCHDOG_MINOR, err);
 433                 goto reboot_out;
 434         }
 435
 436         return 0;
 437
 438
 439 reboot_out:
 440         unregister_reboot_notifier(&it8712f_wdt_notifier);
 441 out:
 442         release_region(address, 1);
 443         return err;
 444 }
 445
 446 static void __exit it8712f_wdt_exit(void)
 447 {
 448         misc_deregister(&it8712f_wdt_miscdev);
 449         unregister_reboot_notifier(&it8712f_wdt_notifier);
 450         release_region(address, 1);
 451 }
 452
 453 module_init(it8712f_wdt_init);
 454 module_exit(it8712f_wdt_exit);