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