1 /* 2 * Watchdog Timer Driver 3 * for ITE IT87xx Environment Control - Low Pin Count Input / Output 4 * 5 * (c) Copyright 2007 Oliver Schuster <olivers137@aol.com> 6 * 7 * Based on softdog.c by Alan Cox, 8 * 83977f_wdt.c by Jose Goncalves, 9 * it87.c by Chris Gauthron, Jean Delvare 10 * 11 * Data-sheets: Publicly available at the ITE website 12 * http://www.ite.com.tw/ 13 * 14 * Support of the watchdog timers, which are available on 15 * IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686, 16 * IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728, 17 * and IT8783. 18 * 19 * This program is free software; you can redistribute it and/or 20 * modify it under the terms of the GNU General Public License 21 * as published by the Free Software Foundation; either version 22 * 2 of the License, or (at your option) any later version. 23 * 24 * This program is distributed in the hope that it will be useful, 25 * but WITHOUT ANY WARRANTY; without even the implied warranty of 26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 27 * GNU General Public License for more details. 28 */ 29 30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 31 32 #include <linux/init.h> 33 #include <linux/io.h> 34 #include <linux/kernel.h> 35 #include <linux/module.h> 36 #include <linux/moduleparam.h> 37 #include <linux/types.h> 38 #include <linux/watchdog.h> 39 40 #define WATCHDOG_NAME "IT87 WDT" 41 42 /* Defaults for Module Parameter */ 43 #define DEFAULT_TIMEOUT 60 44 #define DEFAULT_TESTMODE 0 45 #define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT 46 47 /* IO Ports */ 48 #define REG 0x2e 49 #define VAL 0x2f 50 51 /* Logical device Numbers LDN */ 52 #define GPIO 0x07 53 54 /* Configuration Registers and Functions */ 55 #define LDNREG 0x07 56 #define CHIPID 0x20 57 #define CHIPREV 0x22 58 59 /* Chip Id numbers */ 60 #define NO_DEV_ID 0xffff 61 #define IT8607_ID 0x8607 62 #define IT8620_ID 0x8620 63 #define IT8622_ID 0x8622 64 #define IT8625_ID 0x8625 65 #define IT8628_ID 0x8628 66 #define IT8655_ID 0x8655 67 #define IT8665_ID 0x8665 68 #define IT8686_ID 0x8686 69 #define IT8702_ID 0x8702 70 #define IT8705_ID 0x8705 71 #define IT8712_ID 0x8712 72 #define IT8716_ID 0x8716 73 #define IT8718_ID 0x8718 74 #define IT8720_ID 0x8720 75 #define IT8721_ID 0x8721 76 #define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */ 77 #define IT8728_ID 0x8728 78 #define IT8783_ID 0x8783 79 80 /* GPIO Configuration Registers LDN=0x07 */ 81 #define WDTCTRL 0x71 82 #define WDTCFG 0x72 83 #define WDTVALLSB 0x73 84 #define WDTVALMSB 0x74 85 86 /* GPIO Bits WDTCFG */ 87 #define WDT_TOV1 0x80 88 #define WDT_KRST 0x40 89 #define WDT_TOVE 0x20 90 #define WDT_PWROK 0x10 /* not in it8721 */ 91 #define WDT_INT_MASK 0x0f 92 93 static unsigned int max_units, chip_type; 94 95 static unsigned int timeout = DEFAULT_TIMEOUT; 96 static int testmode = DEFAULT_TESTMODE; 97 static bool nowayout = DEFAULT_NOWAYOUT; 98 99 module_param(timeout, int, 0); 100 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default=" 101 __MODULE_STRING(DEFAULT_TIMEOUT)); 102 module_param(testmode, int, 0); 103 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default=" 104 __MODULE_STRING(DEFAULT_TESTMODE)); 105 module_param(nowayout, bool, 0); 106 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default=" 107 __MODULE_STRING(WATCHDOG_NOWAYOUT)); 108 109 /* Superio Chip */ 110 111 static inline int superio_enter(void) 112 { 113 /* 114 * Try to reserve REG and REG + 1 for exclusive access. 115 */ 116 if (!request_muxed_region(REG, 2, WATCHDOG_NAME)) 117 return -EBUSY; 118 119 outb(0x87, REG); 120 outb(0x01, REG); 121 outb(0x55, REG); 122 outb(0x55, REG); 123 return 0; 124 } 125 126 static inline void superio_exit(void) 127 { 128 outb(0x02, REG); 129 outb(0x02, VAL); 130 release_region(REG, 2); 131 } 132 133 static inline void superio_select(int ldn) 134 { 135 outb(LDNREG, REG); 136 outb(ldn, VAL); 137 } 138 139 static inline int superio_inb(int reg) 140 { 141 outb(reg, REG); 142 return inb(VAL); 143 } 144 145 static inline void superio_outb(int val, int reg) 146 { 147 outb(reg, REG); 148 outb(val, VAL); 149 } 150 151 static inline int superio_inw(int reg) 152 { 153 int val; 154 outb(reg++, REG); 155 val = inb(VAL) << 8; 156 outb(reg, REG); 157 val |= inb(VAL); 158 return val; 159 } 160 161 static inline void superio_outw(int val, int reg) 162 { 163 outb(reg++, REG); 164 outb(val >> 8, VAL); 165 outb(reg, REG); 166 outb(val, VAL); 167 } 168 169 /* Internal function, should be called after superio_select(GPIO) */ 170 static void _wdt_update_timeout(unsigned int t) 171 { 172 unsigned char cfg = WDT_KRST; 173 174 if (testmode) 175 cfg = 0; 176 177 if (t <= max_units) 178 cfg |= WDT_TOV1; 179 else 180 t /= 60; 181 182 if (chip_type != IT8721_ID) 183 cfg |= WDT_PWROK; 184 185 superio_outb(cfg, WDTCFG); 186 superio_outb(t, WDTVALLSB); 187 if (max_units > 255) 188 superio_outb(t >> 8, WDTVALMSB); 189 } 190 191 static int wdt_update_timeout(unsigned int t) 192 { 193 int ret; 194 195 ret = superio_enter(); 196 if (ret) 197 return ret; 198 199 superio_select(GPIO); 200 _wdt_update_timeout(t); 201 superio_exit(); 202 203 return 0; 204 } 205 206 static int wdt_round_time(int t) 207 { 208 t += 59; 209 t -= t % 60; 210 return t; 211 } 212 213 /* watchdog timer handling */ 214 215 static int wdt_start(struct watchdog_device *wdd) 216 { 217 return wdt_update_timeout(wdd->timeout); 218 } 219 220 static int wdt_stop(struct watchdog_device *wdd) 221 { 222 return wdt_update_timeout(0); 223 } 224 225 /** 226 * wdt_set_timeout - set a new timeout value with watchdog ioctl 227 * @t: timeout value in seconds 228 * 229 * The hardware device has a 8 or 16 bit watchdog timer (depends on 230 * chip version) that can be configured to count seconds or minutes. 231 * 232 * Used within WDIOC_SETTIMEOUT watchdog device ioctl. 233 */ 234 235 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 236 { 237 int ret = 0; 238 239 if (t > max_units) 240 t = wdt_round_time(t); 241 242 wdd->timeout = t; 243 244 if (watchdog_hw_running(wdd)) 245 ret = wdt_update_timeout(t); 246 247 return ret; 248 } 249 250 static const struct watchdog_info ident = { 251 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 252 .firmware_version = 1, 253 .identity = WATCHDOG_NAME, 254 }; 255 256 static const struct watchdog_ops wdt_ops = { 257 .owner = THIS_MODULE, 258 .start = wdt_start, 259 .stop = wdt_stop, 260 .set_timeout = wdt_set_timeout, 261 }; 262 263 static struct watchdog_device wdt_dev = { 264 .info = &ident, 265 .ops = &wdt_ops, 266 .min_timeout = 1, 267 }; 268 269 static int __init it87_wdt_init(void) 270 { 271 u8 chip_rev; 272 int rc; 273 274 rc = superio_enter(); 275 if (rc) 276 return rc; 277 278 chip_type = superio_inw(CHIPID); 279 chip_rev = superio_inb(CHIPREV) & 0x0f; 280 superio_exit(); 281 282 switch (chip_type) { 283 case IT8702_ID: 284 max_units = 255; 285 break; 286 case IT8712_ID: 287 max_units = (chip_rev < 8) ? 255 : 65535; 288 break; 289 case IT8716_ID: 290 case IT8726_ID: 291 max_units = 65535; 292 break; 293 case IT8607_ID: 294 case IT8620_ID: 295 case IT8622_ID: 296 case IT8625_ID: 297 case IT8628_ID: 298 case IT8655_ID: 299 case IT8665_ID: 300 case IT8686_ID: 301 case IT8718_ID: 302 case IT8720_ID: 303 case IT8721_ID: 304 case IT8728_ID: 305 case IT8783_ID: 306 max_units = 65535; 307 break; 308 case IT8705_ID: 309 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n", 310 chip_type, chip_rev); 311 return -ENODEV; 312 case NO_DEV_ID: 313 pr_err("no device\n"); 314 return -ENODEV; 315 default: 316 pr_err("Unknown Chip found, Chip %04x Revision %04x\n", 317 chip_type, chip_rev); 318 return -ENODEV; 319 } 320 321 rc = superio_enter(); 322 if (rc) 323 return rc; 324 325 superio_select(GPIO); 326 superio_outb(WDT_TOV1, WDTCFG); 327 superio_outb(0x00, WDTCTRL); 328 superio_exit(); 329 330 if (timeout < 1 || timeout > max_units * 60) { 331 timeout = DEFAULT_TIMEOUT; 332 pr_warn("Timeout value out of range, use default %d sec\n", 333 DEFAULT_TIMEOUT); 334 } 335 336 if (timeout > max_units) 337 timeout = wdt_round_time(timeout); 338 339 wdt_dev.timeout = timeout; 340 wdt_dev.max_timeout = max_units * 60; 341 342 watchdog_stop_on_reboot(&wdt_dev); 343 rc = watchdog_register_device(&wdt_dev); 344 if (rc) { 345 pr_err("Cannot register watchdog device (err=%d)\n", rc); 346 return rc; 347 } 348 349 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 350 chip_type, chip_rev, timeout, nowayout, testmode); 351 352 return 0; 353 } 354 355 static void __exit it87_wdt_exit(void) 356 { 357 watchdog_unregister_device(&wdt_dev); 358 } 359 360 module_init(it87_wdt_init); 361 module_exit(it87_wdt_exit); 362 363 MODULE_AUTHOR("Oliver Schuster"); 364 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O"); 365 MODULE_LICENSE("GPL"); 366