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 0.9.2.pdf
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License as
  14  *      published by the Free Software Foundation; either version 2 of the
  15  *      License, or (at your option) any later version.
  16  *
  17  *      The author(s) of this software shall not be held liable for damages
  18  *      of any nature resulting due to the use of this software. This
  19  *      software is provided AS-IS with no warranties.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/init.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/notifier.h>
  28 #include <linux/reboot.h>
  29 #include <linux/fs.h>
  30 #include <linux/pci.h>
  31 #include <linux/spinlock.h>
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/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 margin = 60;         /* in seconds */
  44 module_param(margin, int, 0);
  45 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  46
  47 static int nowayout = WATCHDOG_NOWAYOUT;
  48 module_param(nowayout, int, 0);
  49 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  50
  51 static struct semaphore it8712f_wdt_sem;
  52 static unsigned expect_close;
  53 static spinlock_t io_lock;
  54
  55 /* Dog Food address - We use the game port address */
  56 static unsigned short address;
  57
  58 #define REG             0x2e    /* The register to read/write */
  59 #define VAL             0x2f    /* The value to read/write */
  60
  61 #define LDN             0x07    /* Register: Logical device select */
  62 #define DEVID           0x20    /* Register: Device ID */
  63 #define DEVREV          0x22    /* Register: Device Revision */
  64 #define ACT_REG         0x30    /* LDN Register: Activation */
  65 #define BASE_REG        0x60    /* LDN Register: Base address */
  66
  67 #define IT8712F_DEVID   0x8712
  68
  69 #define LDN_GPIO        0x07    /* GPIO and Watch Dog Timer */
  70 #define LDN_GAME        0x09    /* Game Port */
  71
  72 #define WDT_CONTROL     0x71    /* WDT Register: Control */
  73 #define WDT_CONFIG      0x72    /* WDT Register: Configuration */
  74 #define WDT_TIMEOUT     0x73    /* WDT Register: Timeout Value */
  75
  76 #define WDT_RESET_GAME  0x10
  77 #define WDT_RESET_KBD   0x20
  78 #define WDT_RESET_MOUSE 0x40
  79 #define WDT_RESET_CIR   0x80
  80
  81 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  82
  83 #define WDT_OUT_PWROK   0x10
  84 #define WDT_OUT_KRST    0x40
  85
  86 static int
  87 superio_inb(int reg)
  88 {
  89         outb(reg, REG);
  90         return inb(VAL);
  91 }
  92
  93 static void
  94 superio_outb(int val, int reg)
  95 {
  96         outb(reg, REG);
  97         outb(val, VAL);
  98 }
  99
 100 static int
 101 superio_inw(int reg)
 102 {
 103         int val;
 104         outb(reg++, REG);
 105         val = inb(VAL) << 8;
 106         outb(reg, REG);
 107         val |= inb(VAL);
 108         return val;
 109 }
 110
 111 static inline void
 112 superio_select(int ldn)
 113 {
 114         outb(LDN, REG);
 115         outb(ldn, VAL);
 116 }
 117
 118 static inline void
 119 superio_enter(void)
 120 {
 121         spin_lock(&io_lock);
 122         outb(0x87, REG);
 123         outb(0x01, REG);
 124         outb(0x55, REG);
 125         outb(0x55, REG);
 126 }
 127
 128 static inline void
 129 superio_exit(void)
 130 {
 131         outb(0x02, REG);
 132         outb(0x02, VAL);
 133         spin_unlock(&io_lock);
 134 }
 135
 136 static inline void
 137 it8712f_wdt_ping(void)
 138 {
 139         inb(address);
 140 }
 141
 142 static void
 143 it8712f_wdt_update_margin(void)
 144 {
 145         int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 146
 147         printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
 148
 149         /* The timeout register only has 8bits wide */
 150         if (margin < 256)
 151                 config |= WDT_UNIT_SEC; /* else UNIT are MINUTES */
 152         superio_outb(config, WDT_CONFIG);
 153
 154         superio_outb((margin > 255) ? (margin / 60) : margin, WDT_TIMEOUT);
 155 }
 156
 157 static void
 158 it8712f_wdt_enable(void)
 159 {
 160         printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
 161         superio_enter();
 162         superio_select(LDN_GPIO);
 163
 164         superio_outb(WDT_RESET_GAME, WDT_CONTROL);
 165
 166         it8712f_wdt_update_margin();
 167
 168         superio_exit();
 169
 170         it8712f_wdt_ping();
 171 }
 172
 173 static void
 174 it8712f_wdt_disable(void)
 175 {
 176         printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 177
 178         superio_enter();
 179         superio_select(LDN_GPIO);
 180
 181         superio_outb(0, WDT_CONFIG);
 182         superio_outb(0, WDT_CONTROL);
 183         superio_outb(0, WDT_TIMEOUT);
 184
 185         superio_exit();
 186 }
 187
 188 static int
 189 it8712f_wdt_notify(struct notifier_block *this,
 190                     unsigned long code, void *unused)
 191 {
 192         if (code == SYS_HALT || code == SYS_POWER_OFF)
 193                 if (!nowayout)
 194                         it8712f_wdt_disable();
 195
 196         return NOTIFY_DONE;
 197 }
 198
 199 static struct notifier_block it8712f_wdt_notifier = {
 200         .notifier_call = it8712f_wdt_notify,
 201 };
 202
 203 static ssize_t
 204 it8712f_wdt_write(struct file *file, const char __user *data,
 205         size_t len, loff_t *ppos)
 206 {
 207         /* check for a magic close character */
 208         if (len) {
 209                 size_t i;
 210
 211                 it8712f_wdt_ping();
 212
 213                 expect_close = 0;
 214                 for (i = 0; i < len; ++i) {
 215                         char c;
 216                         if (get_user(c, data+i))
 217                                 return -EFAULT;
 218                         if (c == 'V')
 219                                 expect_close = 42;
 220                 }
 221         }
 222
 223         return len;
 224 }
 225
 226 static int
 227 it8712f_wdt_ioctl(struct inode *inode, struct file *file,
 228         unsigned int cmd, unsigned long arg)
 229 {
 230         void __user *argp = (void __user *)arg;
 231         int __user *p = argp;
 232         static struct watchdog_info ident = {
 233                 .identity = "IT8712F Watchdog",
 234                 .firmware_version = 1,
 235                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 236         };
 237         int new_margin;
 238
 239         switch (cmd) {
 240         default:
 241                 return -ENOTTY;
 242         case WDIOC_GETSUPPORT:
 243                 if (copy_to_user(argp, &ident, sizeof(ident)))
 244                         return -EFAULT;
 245                 return 0;
 246         case WDIOC_GETSTATUS:
 247         case WDIOC_GETBOOTSTATUS:
 248                 return put_user(0, p);
 249         case WDIOC_KEEPALIVE:
 250                 it8712f_wdt_ping();
 251                 return 0;
 252         case WDIOC_SETTIMEOUT:
 253                 if (get_user(new_margin, p))
 254                         return -EFAULT;
 255                 if (new_margin < 1)
 256                         return -EINVAL;
 257                 margin = new_margin;
 258                 superio_enter();
 259                 superio_select(LDN_GPIO);
 260
 261                 it8712f_wdt_update_margin();
 262
 263                 superio_exit();
 264                 it8712f_wdt_ping();
 265         case WDIOC_GETTIMEOUT:
 266                 if (put_user(margin, p))
 267                         return -EFAULT;
 268                 return 0;
 269         }
 270 }
 271
 272 static int
 273 it8712f_wdt_open(struct inode *inode, struct file *file)
 274 {
 275         /* only allow one at a time */
 276         if (down_trylock(&it8712f_wdt_sem))
 277                 return -EBUSY;
 278         it8712f_wdt_enable();
 279
 280         return nonseekable_open(inode, file);
 281 }
 282
 283 static int
 284 it8712f_wdt_release(struct inode *inode, struct file *file)
 285 {
 286         if (expect_close != 42) {
 287                 printk(KERN_WARNING NAME
 288                         ": watchdog device closed unexpectedly, will not"
 289                         " disable the watchdog timer\n");
 290         } else if (!nowayout) {
 291                 it8712f_wdt_disable();
 292         }
 293         expect_close = 0;
 294         up(&it8712f_wdt_sem);
 295
 296         return 0;
 297 }
 298
 299 static const struct file_operations it8712f_wdt_fops = {
 300         .owner = THIS_MODULE,
 301         .llseek = no_llseek,
 302         .write = it8712f_wdt_write,
 303         .ioctl = it8712f_wdt_ioctl,
 304         .open = it8712f_wdt_open,
 305         .release = it8712f_wdt_release,
 306 };
 307
 308 static struct miscdevice it8712f_wdt_miscdev = {
 309         .minor = WATCHDOG_MINOR,
 310         .name = "watchdog",
 311         .fops = &it8712f_wdt_fops,
 312 };
 313
 314 static int __init
 315 it8712f_wdt_find(unsigned short *address)
 316 {
 317         int err = -ENODEV;
 318         int chip_type;
 319
 320         superio_enter();
 321         chip_type = superio_inw(DEVID);
 322         if (chip_type != IT8712F_DEVID)
 323                 goto exit;
 324
 325         superio_select(LDN_GAME);
 326         superio_outb(1, ACT_REG);
 327         if (!(superio_inb(ACT_REG) & 0x01)) {
 328                 printk(KERN_ERR NAME ": Device not activated, skipping\n");
 329                 goto exit;
 330         }
 331
 332         *address = superio_inw(BASE_REG);
 333         if (*address == 0) {
 334                 printk(KERN_ERR NAME ": Base address not set, skipping\n");
 335                 goto exit;
 336         }
 337
 338         err = 0;
 339         printk(KERN_DEBUG NAME ": Found IT%04xF chip revision %d - "
 340                 "using DogFood address 0x%x\n",
 341                 chip_type, superio_inb(DEVREV) & 0x0f, *address);
 342
 343 exit:
 344         superio_exit();
 345         return err;
 346 }
 347
 348 static int __init
 349 it8712f_wdt_init(void)
 350 {
 351         int err = 0;
 352
 353         spin_lock_init(&io_lock);
 354
 355         if (it8712f_wdt_find(&address))
 356                 return -ENODEV;
 357
 358         if (!request_region(address, 1, "IT8712F Watchdog")) {
 359                 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 360                 return -EBUSY;
 361         }
 362
 363         it8712f_wdt_disable();
 364
 365         sema_init(&it8712f_wdt_sem, 1);
 366
 367         err = register_reboot_notifier(&it8712f_wdt_notifier);
 368         if (err) {
 369                 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 370                 goto out;
 371         }
 372
 373         err = misc_register(&it8712f_wdt_miscdev);
 374         if (err) {
 375                 printk(KERN_ERR NAME
 376                         ": cannot register miscdev on minor=%d (err=%d)\n",
 377                         WATCHDOG_MINOR, err);
 378                 goto reboot_out;
 379         }
 380
 381         return 0;
 382
 383
 384 reboot_out:
 385         unregister_reboot_notifier(&it8712f_wdt_notifier);
 386 out:
 387         release_region(address, 1);
 388         return err;
 389 }
 390
 391 static void __exit
 392 it8712f_wdt_exit(void)
 393 {
 394         misc_deregister(&it8712f_wdt_miscdev);
 395         unregister_reboot_notifier(&it8712f_wdt_notifier);
 396         release_region(address, 1);
 397 }
 398
 399 module_init(it8712f_wdt_init);
 400 module_exit(it8712f_wdt_exit);