1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Watchdog Timer Driver 4 * for ITE IT87xx Environment Control - Low Pin Count Input / Output 5 * 6 * (c) Copyright 2007 Oliver Schuster <olivers137@aol.com> 7 * 8 * Based on softdog.c by Alan Cox, 9 * 83977f_wdt.c by Jose Goncalves, 10 * it87.c by Chris Gauthron, Jean Delvare 11 * 12 * Data-sheets: Publicly available at the ITE website 13 * http://www.ite.com.tw/ 14 * 15 * Support of the watchdog timers, which are available on 16 * IT8607, IT8613, IT8620, IT8622, IT8625, IT8628, IT8655, IT8659, 17 * IT8665, IT8686, IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, 18 * IT8726, IT8728, IT8772, IT8783, IT8784 and IT8786. 19 */ 20 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 22 23 #include <linux/init.h> 24 #include <linux/io.h> 25 #include <linux/kernel.h> 26 #include <linux/module.h> 27 #include <linux/moduleparam.h> 28 #include <linux/types.h> 29 #include <linux/watchdog.h> 30 31 #define WATCHDOG_NAME "IT87 WDT" 32 33 /* Defaults for Module Parameter */ 34 #define DEFAULT_TIMEOUT 60 35 #define DEFAULT_TESTMODE 0 36 #define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT 37 38 /* IO Ports */ 39 #define REG 0x2e 40 #define VAL 0x2f 41 42 /* Logical device Numbers LDN */ 43 #define GPIO 0x07 44 45 /* Configuration Registers and Functions */ 46 #define LDNREG 0x07 47 #define CHIPID 0x20 48 #define CHIPREV 0x22 49 50 /* Chip Id numbers */ 51 #define NO_DEV_ID 0xffff 52 #define IT8607_ID 0x8607 53 #define IT8613_ID 0x8613 54 #define IT8620_ID 0x8620 55 #define IT8622_ID 0x8622 56 #define IT8625_ID 0x8625 57 #define IT8628_ID 0x8628 58 #define IT8655_ID 0x8655 59 #define IT8659_ID 0x8659 60 #define IT8665_ID 0x8665 61 #define IT8686_ID 0x8686 62 #define IT8702_ID 0x8702 63 #define IT8705_ID 0x8705 64 #define IT8712_ID 0x8712 65 #define IT8716_ID 0x8716 66 #define IT8718_ID 0x8718 67 #define IT8720_ID 0x8720 68 #define IT8721_ID 0x8721 69 #define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */ 70 #define IT8728_ID 0x8728 71 #define IT8772_ID 0x8772 72 #define IT8783_ID 0x8783 73 #define IT8784_ID 0x8784 74 #define IT8786_ID 0x8786 75 76 /* GPIO Configuration Registers LDN=0x07 */ 77 #define WDTCTRL 0x71 78 #define WDTCFG 0x72 79 #define WDTVALLSB 0x73 80 #define WDTVALMSB 0x74 81 82 /* GPIO Bits WDTCFG */ 83 #define WDT_TOV1 0x80 84 #define WDT_KRST 0x40 85 #define WDT_TOVE 0x20 86 #define WDT_PWROK 0x10 /* not in it8721 */ 87 #define WDT_INT_MASK 0x0f 88 89 static unsigned int max_units, chip_type; 90 91 static unsigned int timeout = DEFAULT_TIMEOUT; 92 static int testmode = DEFAULT_TESTMODE; 93 static bool nowayout = DEFAULT_NOWAYOUT; 94 95 module_param(timeout, int, 0); 96 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default=" 97 __MODULE_STRING(DEFAULT_TIMEOUT)); 98 module_param(testmode, int, 0); 99 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default=" 100 __MODULE_STRING(DEFAULT_TESTMODE)); 101 module_param(nowayout, bool, 0); 102 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default=" 103 __MODULE_STRING(WATCHDOG_NOWAYOUT)); 104 105 /* Superio Chip */ 106 107 static inline int superio_enter(void) 108 { 109 /* 110 * Try to reserve REG and REG + 1 for exclusive access. 111 */ 112 if (!request_muxed_region(REG, 2, WATCHDOG_NAME)) 113 return -EBUSY; 114 115 outb(0x87, REG); 116 outb(0x01, REG); 117 outb(0x55, REG); 118 outb(0x55, REG); 119 return 0; 120 } 121 122 static inline void superio_exit(void) 123 { 124 outb(0x02, REG); 125 outb(0x02, VAL); 126 release_region(REG, 2); 127 } 128 129 static inline void superio_select(int ldn) 130 { 131 outb(LDNREG, REG); 132 outb(ldn, VAL); 133 } 134 135 static inline int superio_inb(int reg) 136 { 137 outb(reg, REG); 138 return inb(VAL); 139 } 140 141 static inline void superio_outb(int val, int reg) 142 { 143 outb(reg, REG); 144 outb(val, VAL); 145 } 146 147 static inline int superio_inw(int reg) 148 { 149 int val; 150 151 outb(reg++, REG); 152 val = inb(VAL) << 8; 153 outb(reg, REG); 154 val |= inb(VAL); 155 return val; 156 } 157 158 /* Internal function, should be called after superio_select(GPIO) */ 159 static void _wdt_update_timeout(unsigned int t) 160 { 161 unsigned char cfg = WDT_KRST; 162 163 if (testmode) 164 cfg = 0; 165 166 if (t <= max_units) 167 cfg |= WDT_TOV1; 168 else 169 t /= 60; 170 171 if (chip_type != IT8721_ID) 172 cfg |= WDT_PWROK; 173 174 superio_outb(cfg, WDTCFG); 175 superio_outb(t, WDTVALLSB); 176 if (max_units > 255) 177 superio_outb(t >> 8, WDTVALMSB); 178 } 179 180 static int wdt_update_timeout(unsigned int t) 181 { 182 int ret; 183 184 ret = superio_enter(); 185 if (ret) 186 return ret; 187 188 superio_select(GPIO); 189 _wdt_update_timeout(t); 190 superio_exit(); 191 192 return 0; 193 } 194 195 static int wdt_round_time(int t) 196 { 197 t += 59; 198 t -= t % 60; 199 return t; 200 } 201 202 /* watchdog timer handling */ 203 204 static int wdt_start(struct watchdog_device *wdd) 205 { 206 return wdt_update_timeout(wdd->timeout); 207 } 208 209 static int wdt_stop(struct watchdog_device *wdd) 210 { 211 return wdt_update_timeout(0); 212 } 213 214 /** 215 * wdt_set_timeout - set a new timeout value with watchdog ioctl 216 * @wdd: pointer to the watchdog_device structure 217 * @t: timeout value in seconds 218 * 219 * The hardware device has a 8 or 16 bit watchdog timer (depends on 220 * chip version) that can be configured to count seconds or minutes. 221 * 222 * Used within WDIOC_SETTIMEOUT watchdog device ioctl. 223 * 224 * Return: 0 if the timeout was set successfully, or a negative error code on 225 * failure. 226 */ 227 228 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 229 { 230 int ret = 0; 231 232 if (t > max_units) 233 t = wdt_round_time(t); 234 235 wdd->timeout = t; 236 237 if (watchdog_hw_running(wdd)) 238 ret = wdt_update_timeout(t); 239 240 return ret; 241 } 242 243 static const struct watchdog_info ident = { 244 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 245 .firmware_version = 1, 246 .identity = WATCHDOG_NAME, 247 }; 248 249 static const struct watchdog_ops wdt_ops = { 250 .owner = THIS_MODULE, 251 .start = wdt_start, 252 .stop = wdt_stop, 253 .set_timeout = wdt_set_timeout, 254 }; 255 256 static struct watchdog_device wdt_dev = { 257 .info = &ident, 258 .ops = &wdt_ops, 259 .min_timeout = 1, 260 }; 261 262 static int __init it87_wdt_init(void) 263 { 264 u8 chip_rev; 265 u8 ctrl; 266 int rc; 267 268 rc = superio_enter(); 269 if (rc) 270 return rc; 271 272 chip_type = superio_inw(CHIPID); 273 chip_rev = superio_inb(CHIPREV) & 0x0f; 274 superio_exit(); 275 276 switch (chip_type) { 277 case IT8702_ID: 278 max_units = 255; 279 break; 280 case IT8712_ID: 281 max_units = (chip_rev < 8) ? 255 : 65535; 282 break; 283 case IT8607_ID: 284 case IT8613_ID: 285 case IT8620_ID: 286 case IT8622_ID: 287 case IT8625_ID: 288 case IT8628_ID: 289 case IT8655_ID: 290 case IT8659_ID: 291 case IT8665_ID: 292 case IT8686_ID: 293 case IT8716_ID: 294 case IT8718_ID: 295 case IT8720_ID: 296 case IT8721_ID: 297 case IT8726_ID: 298 case IT8728_ID: 299 case IT8772_ID: 300 case IT8783_ID: 301 case IT8784_ID: 302 case IT8786_ID: 303 max_units = 65535; 304 break; 305 case IT8705_ID: 306 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n", 307 chip_type, chip_rev); 308 return -ENODEV; 309 case NO_DEV_ID: 310 pr_err("no device\n"); 311 return -ENODEV; 312 default: 313 pr_err("Unknown Chip found, Chip %04x Revision %04x\n", 314 chip_type, chip_rev); 315 return -ENODEV; 316 } 317 318 rc = superio_enter(); 319 if (rc) 320 return rc; 321 322 superio_select(GPIO); 323 superio_outb(WDT_TOV1, WDTCFG); 324 325 switch (chip_type) { 326 case IT8784_ID: 327 case IT8786_ID: 328 ctrl = superio_inb(WDTCTRL); 329 ctrl &= 0x08; 330 superio_outb(ctrl, WDTCTRL); 331 break; 332 default: 333 superio_outb(0x00, WDTCTRL); 334 } 335 336 superio_exit(); 337 338 if (timeout < 1 || timeout > max_units * 60) { 339 timeout = DEFAULT_TIMEOUT; 340 pr_warn("Timeout value out of range, use default %d sec\n", 341 DEFAULT_TIMEOUT); 342 } 343 344 if (timeout > max_units) 345 timeout = wdt_round_time(timeout); 346 347 wdt_dev.timeout = timeout; 348 wdt_dev.max_timeout = max_units * 60; 349 350 watchdog_stop_on_reboot(&wdt_dev); 351 rc = watchdog_register_device(&wdt_dev); 352 if (rc) { 353 pr_err("Cannot register watchdog device (err=%d)\n", rc); 354 return rc; 355 } 356 357 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 358 chip_type, chip_rev, timeout, nowayout, testmode); 359 360 return 0; 361 } 362 363 static void __exit it87_wdt_exit(void) 364 { 365 watchdog_unregister_device(&wdt_dev); 366 } 367 368 module_init(it87_wdt_init); 369 module_exit(it87_wdt_exit); 370 371 MODULE_AUTHOR("Oliver Schuster"); 372 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O"); 373 MODULE_LICENSE("GPL"); 374