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, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686, 17 * IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728, 18 * IT8772, IT8783 and IT8784. 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 IT8620_ID 0x8620 54 #define IT8622_ID 0x8622 55 #define IT8625_ID 0x8625 56 #define IT8628_ID 0x8628 57 #define IT8655_ID 0x8655 58 #define IT8665_ID 0x8665 59 #define IT8686_ID 0x8686 60 #define IT8702_ID 0x8702 61 #define IT8705_ID 0x8705 62 #define IT8712_ID 0x8712 63 #define IT8716_ID 0x8716 64 #define IT8718_ID 0x8718 65 #define IT8720_ID 0x8720 66 #define IT8721_ID 0x8721 67 #define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */ 68 #define IT8728_ID 0x8728 69 #define IT8772_ID 0x8772 70 #define IT8783_ID 0x8783 71 #define IT8784_ID 0x8784 72 #define IT8786_ID 0x8786 73 74 /* GPIO Configuration Registers LDN=0x07 */ 75 #define WDTCTRL 0x71 76 #define WDTCFG 0x72 77 #define WDTVALLSB 0x73 78 #define WDTVALMSB 0x74 79 80 /* GPIO Bits WDTCFG */ 81 #define WDT_TOV1 0x80 82 #define WDT_KRST 0x40 83 #define WDT_TOVE 0x20 84 #define WDT_PWROK 0x10 /* not in it8721 */ 85 #define WDT_INT_MASK 0x0f 86 87 static unsigned int max_units, chip_type; 88 89 static unsigned int timeout = DEFAULT_TIMEOUT; 90 static int testmode = DEFAULT_TESTMODE; 91 static bool nowayout = DEFAULT_NOWAYOUT; 92 93 module_param(timeout, int, 0); 94 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default=" 95 __MODULE_STRING(DEFAULT_TIMEOUT)); 96 module_param(testmode, int, 0); 97 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default=" 98 __MODULE_STRING(DEFAULT_TESTMODE)); 99 module_param(nowayout, bool, 0); 100 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default=" 101 __MODULE_STRING(WATCHDOG_NOWAYOUT)); 102 103 /* Superio Chip */ 104 105 static inline int superio_enter(void) 106 { 107 /* 108 * Try to reserve REG and REG + 1 for exclusive access. 109 */ 110 if (!request_muxed_region(REG, 2, WATCHDOG_NAME)) 111 return -EBUSY; 112 113 outb(0x87, REG); 114 outb(0x01, REG); 115 outb(0x55, REG); 116 outb(0x55, REG); 117 return 0; 118 } 119 120 static inline void superio_exit(void) 121 { 122 outb(0x02, REG); 123 outb(0x02, VAL); 124 release_region(REG, 2); 125 } 126 127 static inline void superio_select(int ldn) 128 { 129 outb(LDNREG, REG); 130 outb(ldn, VAL); 131 } 132 133 static inline int superio_inb(int reg) 134 { 135 outb(reg, REG); 136 return inb(VAL); 137 } 138 139 static inline void superio_outb(int val, int reg) 140 { 141 outb(reg, REG); 142 outb(val, VAL); 143 } 144 145 static inline int superio_inw(int reg) 146 { 147 int val; 148 outb(reg++, REG); 149 val = inb(VAL) << 8; 150 outb(reg, REG); 151 val |= inb(VAL); 152 return val; 153 } 154 155 static inline void superio_outw(int val, int reg) 156 { 157 outb(reg++, REG); 158 outb(val >> 8, VAL); 159 outb(reg, REG); 160 outb(val, VAL); 161 } 162 163 /* Internal function, should be called after superio_select(GPIO) */ 164 static void _wdt_update_timeout(unsigned int t) 165 { 166 unsigned char cfg = WDT_KRST; 167 168 if (testmode) 169 cfg = 0; 170 171 if (t <= max_units) 172 cfg |= WDT_TOV1; 173 else 174 t /= 60; 175 176 if (chip_type != IT8721_ID) 177 cfg |= WDT_PWROK; 178 179 superio_outb(cfg, WDTCFG); 180 superio_outb(t, WDTVALLSB); 181 if (max_units > 255) 182 superio_outb(t >> 8, WDTVALMSB); 183 } 184 185 static int wdt_update_timeout(unsigned int t) 186 { 187 int ret; 188 189 ret = superio_enter(); 190 if (ret) 191 return ret; 192 193 superio_select(GPIO); 194 _wdt_update_timeout(t); 195 superio_exit(); 196 197 return 0; 198 } 199 200 static int wdt_round_time(int t) 201 { 202 t += 59; 203 t -= t % 60; 204 return t; 205 } 206 207 /* watchdog timer handling */ 208 209 static int wdt_start(struct watchdog_device *wdd) 210 { 211 return wdt_update_timeout(wdd->timeout); 212 } 213 214 static int wdt_stop(struct watchdog_device *wdd) 215 { 216 return wdt_update_timeout(0); 217 } 218 219 /** 220 * wdt_set_timeout - set a new timeout value with watchdog ioctl 221 * @t: timeout value in seconds 222 * 223 * The hardware device has a 8 or 16 bit watchdog timer (depends on 224 * chip version) that can be configured to count seconds or minutes. 225 * 226 * Used within WDIOC_SETTIMEOUT watchdog device ioctl. 227 */ 228 229 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 230 { 231 int ret = 0; 232 233 if (t > max_units) 234 t = wdt_round_time(t); 235 236 wdd->timeout = t; 237 238 if (watchdog_hw_running(wdd)) 239 ret = wdt_update_timeout(t); 240 241 return ret; 242 } 243 244 static const struct watchdog_info ident = { 245 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 246 .firmware_version = 1, 247 .identity = WATCHDOG_NAME, 248 }; 249 250 static const struct watchdog_ops wdt_ops = { 251 .owner = THIS_MODULE, 252 .start = wdt_start, 253 .stop = wdt_stop, 254 .set_timeout = wdt_set_timeout, 255 }; 256 257 static struct watchdog_device wdt_dev = { 258 .info = &ident, 259 .ops = &wdt_ops, 260 .min_timeout = 1, 261 }; 262 263 static int __init it87_wdt_init(void) 264 { 265 u8 chip_rev; 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 IT8716_ID: 284 case IT8726_ID: 285 max_units = 65535; 286 break; 287 case IT8607_ID: 288 case IT8620_ID: 289 case IT8622_ID: 290 case IT8625_ID: 291 case IT8628_ID: 292 case IT8655_ID: 293 case IT8665_ID: 294 case IT8686_ID: 295 case IT8718_ID: 296 case IT8720_ID: 297 case IT8721_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 superio_outb(0x00, WDTCTRL); 325 superio_exit(); 326 327 if (timeout < 1 || timeout > max_units * 60) { 328 timeout = DEFAULT_TIMEOUT; 329 pr_warn("Timeout value out of range, use default %d sec\n", 330 DEFAULT_TIMEOUT); 331 } 332 333 if (timeout > max_units) 334 timeout = wdt_round_time(timeout); 335 336 wdt_dev.timeout = timeout; 337 wdt_dev.max_timeout = max_units * 60; 338 339 watchdog_stop_on_reboot(&wdt_dev); 340 rc = watchdog_register_device(&wdt_dev); 341 if (rc) { 342 pr_err("Cannot register watchdog device (err=%d)\n", rc); 343 return rc; 344 } 345 346 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 347 chip_type, chip_rev, timeout, nowayout, testmode); 348 349 return 0; 350 } 351 352 static void __exit it87_wdt_exit(void) 353 { 354 watchdog_unregister_device(&wdt_dev); 355 } 356 357 module_init(it87_wdt_init); 358 module_exit(it87_wdt_exit); 359 360 MODULE_AUTHOR("Oliver Schuster"); 361 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O"); 362 MODULE_LICENSE("GPL"); 363