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, IT8665, 17 * IT8686, IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, 18 * IT8728, 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 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 IT8665_ID 0x8665 60 #define IT8686_ID 0x8686 61 #define IT8702_ID 0x8702 62 #define IT8705_ID 0x8705 63 #define IT8712_ID 0x8712 64 #define IT8716_ID 0x8716 65 #define IT8718_ID 0x8718 66 #define IT8720_ID 0x8720 67 #define IT8721_ID 0x8721 68 #define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */ 69 #define IT8728_ID 0x8728 70 #define IT8772_ID 0x8772 71 #define IT8783_ID 0x8783 72 #define IT8784_ID 0x8784 73 #define IT8786_ID 0x8786 74 75 /* GPIO Configuration Registers LDN=0x07 */ 76 #define WDTCTRL 0x71 77 #define WDTCFG 0x72 78 #define WDTVALLSB 0x73 79 #define WDTVALMSB 0x74 80 81 /* GPIO Bits WDTCFG */ 82 #define WDT_TOV1 0x80 83 #define WDT_KRST 0x40 84 #define WDT_TOVE 0x20 85 #define WDT_PWROK 0x10 /* not in it8721 */ 86 #define WDT_INT_MASK 0x0f 87 88 static unsigned int max_units, chip_type; 89 90 static unsigned int timeout = DEFAULT_TIMEOUT; 91 static int testmode = DEFAULT_TESTMODE; 92 static bool nowayout = DEFAULT_NOWAYOUT; 93 94 module_param(timeout, int, 0); 95 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default=" 96 __MODULE_STRING(DEFAULT_TIMEOUT)); 97 module_param(testmode, int, 0); 98 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default=" 99 __MODULE_STRING(DEFAULT_TESTMODE)); 100 module_param(nowayout, bool, 0); 101 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default=" 102 __MODULE_STRING(WATCHDOG_NOWAYOUT)); 103 104 /* Superio Chip */ 105 106 static inline int superio_enter(void) 107 { 108 /* 109 * Try to reserve REG and REG + 1 for exclusive access. 110 */ 111 if (!request_muxed_region(REG, 2, WATCHDOG_NAME)) 112 return -EBUSY; 113 114 outb(0x87, REG); 115 outb(0x01, REG); 116 outb(0x55, REG); 117 outb(0x55, REG); 118 return 0; 119 } 120 121 static inline void superio_exit(void) 122 { 123 outb(0x02, REG); 124 outb(0x02, VAL); 125 release_region(REG, 2); 126 } 127 128 static inline void superio_select(int ldn) 129 { 130 outb(LDNREG, REG); 131 outb(ldn, VAL); 132 } 133 134 static inline int superio_inb(int reg) 135 { 136 outb(reg, REG); 137 return inb(VAL); 138 } 139 140 static inline void superio_outb(int val, int reg) 141 { 142 outb(reg, REG); 143 outb(val, VAL); 144 } 145 146 static inline int superio_inw(int reg) 147 { 148 int val; 149 outb(reg++, REG); 150 val = inb(VAL) << 8; 151 outb(reg, REG); 152 val |= inb(VAL); 153 return val; 154 } 155 156 /* Internal function, should be called after superio_select(GPIO) */ 157 static void _wdt_update_timeout(unsigned int t) 158 { 159 unsigned char cfg = WDT_KRST; 160 161 if (testmode) 162 cfg = 0; 163 164 if (t <= max_units) 165 cfg |= WDT_TOV1; 166 else 167 t /= 60; 168 169 if (chip_type != IT8721_ID) 170 cfg |= WDT_PWROK; 171 172 superio_outb(cfg, WDTCFG); 173 superio_outb(t, WDTVALLSB); 174 if (max_units > 255) 175 superio_outb(t >> 8, WDTVALMSB); 176 } 177 178 static int wdt_update_timeout(unsigned int t) 179 { 180 int ret; 181 182 ret = superio_enter(); 183 if (ret) 184 return ret; 185 186 superio_select(GPIO); 187 _wdt_update_timeout(t); 188 superio_exit(); 189 190 return 0; 191 } 192 193 static int wdt_round_time(int t) 194 { 195 t += 59; 196 t -= t % 60; 197 return t; 198 } 199 200 /* watchdog timer handling */ 201 202 static int wdt_start(struct watchdog_device *wdd) 203 { 204 return wdt_update_timeout(wdd->timeout); 205 } 206 207 static int wdt_stop(struct watchdog_device *wdd) 208 { 209 return wdt_update_timeout(0); 210 } 211 212 /** 213 * wdt_set_timeout - set a new timeout value with watchdog ioctl 214 * @t: timeout value in seconds 215 * 216 * The hardware device has a 8 or 16 bit watchdog timer (depends on 217 * chip version) that can be configured to count seconds or minutes. 218 * 219 * Used within WDIOC_SETTIMEOUT watchdog device ioctl. 220 */ 221 222 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 223 { 224 int ret = 0; 225 226 if (t > max_units) 227 t = wdt_round_time(t); 228 229 wdd->timeout = t; 230 231 if (watchdog_hw_running(wdd)) 232 ret = wdt_update_timeout(t); 233 234 return ret; 235 } 236 237 static const struct watchdog_info ident = { 238 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 239 .firmware_version = 1, 240 .identity = WATCHDOG_NAME, 241 }; 242 243 static const struct watchdog_ops wdt_ops = { 244 .owner = THIS_MODULE, 245 .start = wdt_start, 246 .stop = wdt_stop, 247 .set_timeout = wdt_set_timeout, 248 }; 249 250 static struct watchdog_device wdt_dev = { 251 .info = &ident, 252 .ops = &wdt_ops, 253 .min_timeout = 1, 254 }; 255 256 static int __init it87_wdt_init(void) 257 { 258 u8 chip_rev; 259 int rc; 260 261 rc = superio_enter(); 262 if (rc) 263 return rc; 264 265 chip_type = superio_inw(CHIPID); 266 chip_rev = superio_inb(CHIPREV) & 0x0f; 267 superio_exit(); 268 269 switch (chip_type) { 270 case IT8702_ID: 271 max_units = 255; 272 break; 273 case IT8712_ID: 274 max_units = (chip_rev < 8) ? 255 : 65535; 275 break; 276 case IT8716_ID: 277 case IT8726_ID: 278 max_units = 65535; 279 break; 280 case IT8607_ID: 281 case IT8613_ID: 282 case IT8620_ID: 283 case IT8622_ID: 284 case IT8625_ID: 285 case IT8628_ID: 286 case IT8655_ID: 287 case IT8665_ID: 288 case IT8686_ID: 289 case IT8718_ID: 290 case IT8720_ID: 291 case IT8721_ID: 292 case IT8728_ID: 293 case IT8772_ID: 294 case IT8783_ID: 295 case IT8784_ID: 296 case IT8786_ID: 297 max_units = 65535; 298 break; 299 case IT8705_ID: 300 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n", 301 chip_type, chip_rev); 302 return -ENODEV; 303 case NO_DEV_ID: 304 pr_err("no device\n"); 305 return -ENODEV; 306 default: 307 pr_err("Unknown Chip found, Chip %04x Revision %04x\n", 308 chip_type, chip_rev); 309 return -ENODEV; 310 } 311 312 rc = superio_enter(); 313 if (rc) 314 return rc; 315 316 superio_select(GPIO); 317 superio_outb(WDT_TOV1, WDTCFG); 318 superio_outb(0x00, WDTCTRL); 319 superio_exit(); 320 321 if (timeout < 1 || timeout > max_units * 60) { 322 timeout = DEFAULT_TIMEOUT; 323 pr_warn("Timeout value out of range, use default %d sec\n", 324 DEFAULT_TIMEOUT); 325 } 326 327 if (timeout > max_units) 328 timeout = wdt_round_time(timeout); 329 330 wdt_dev.timeout = timeout; 331 wdt_dev.max_timeout = max_units * 60; 332 333 watchdog_stop_on_reboot(&wdt_dev); 334 rc = watchdog_register_device(&wdt_dev); 335 if (rc) { 336 pr_err("Cannot register watchdog device (err=%d)\n", rc); 337 return rc; 338 } 339 340 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 341 chip_type, chip_rev, timeout, nowayout, testmode); 342 343 return 0; 344 } 345 346 static void __exit it87_wdt_exit(void) 347 { 348 watchdog_unregister_device(&wdt_dev); 349 } 350 351 module_init(it87_wdt_init); 352 module_exit(it87_wdt_exit); 353 354 MODULE_AUTHOR("Oliver Schuster"); 355 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O"); 356 MODULE_LICENSE("GPL"); 357