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 * and IT8783. 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 IT8783_ID 0x8783 70 #define IT8786_ID 0x8786 71 72 /* GPIO Configuration Registers LDN=0x07 */ 73 #define WDTCTRL 0x71 74 #define WDTCFG 0x72 75 #define WDTVALLSB 0x73 76 #define WDTVALMSB 0x74 77 78 /* GPIO Bits WDTCFG */ 79 #define WDT_TOV1 0x80 80 #define WDT_KRST 0x40 81 #define WDT_TOVE 0x20 82 #define WDT_PWROK 0x10 /* not in it8721 */ 83 #define WDT_INT_MASK 0x0f 84 85 static unsigned int max_units, chip_type; 86 87 static unsigned int timeout = DEFAULT_TIMEOUT; 88 static int testmode = DEFAULT_TESTMODE; 89 static bool nowayout = DEFAULT_NOWAYOUT; 90 91 module_param(timeout, int, 0); 92 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default=" 93 __MODULE_STRING(DEFAULT_TIMEOUT)); 94 module_param(testmode, int, 0); 95 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default=" 96 __MODULE_STRING(DEFAULT_TESTMODE)); 97 module_param(nowayout, bool, 0); 98 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default=" 99 __MODULE_STRING(WATCHDOG_NOWAYOUT)); 100 101 /* Superio Chip */ 102 103 static inline int superio_enter(void) 104 { 105 /* 106 * Try to reserve REG and REG + 1 for exclusive access. 107 */ 108 if (!request_muxed_region(REG, 2, WATCHDOG_NAME)) 109 return -EBUSY; 110 111 outb(0x87, REG); 112 outb(0x01, REG); 113 outb(0x55, REG); 114 outb(0x55, REG); 115 return 0; 116 } 117 118 static inline void superio_exit(void) 119 { 120 outb(0x02, REG); 121 outb(0x02, VAL); 122 release_region(REG, 2); 123 } 124 125 static inline void superio_select(int ldn) 126 { 127 outb(LDNREG, REG); 128 outb(ldn, VAL); 129 } 130 131 static inline int superio_inb(int reg) 132 { 133 outb(reg, REG); 134 return inb(VAL); 135 } 136 137 static inline void superio_outb(int val, int reg) 138 { 139 outb(reg, REG); 140 outb(val, VAL); 141 } 142 143 static inline int superio_inw(int reg) 144 { 145 int val; 146 outb(reg++, REG); 147 val = inb(VAL) << 8; 148 outb(reg, REG); 149 val |= inb(VAL); 150 return val; 151 } 152 153 static inline void superio_outw(int val, int reg) 154 { 155 outb(reg++, REG); 156 outb(val >> 8, VAL); 157 outb(reg, REG); 158 outb(val, VAL); 159 } 160 161 /* Internal function, should be called after superio_select(GPIO) */ 162 static void _wdt_update_timeout(unsigned int t) 163 { 164 unsigned char cfg = WDT_KRST; 165 166 if (testmode) 167 cfg = 0; 168 169 if (t <= max_units) 170 cfg |= WDT_TOV1; 171 else 172 t /= 60; 173 174 if (chip_type != IT8721_ID) 175 cfg |= WDT_PWROK; 176 177 superio_outb(cfg, WDTCFG); 178 superio_outb(t, WDTVALLSB); 179 if (max_units > 255) 180 superio_outb(t >> 8, WDTVALMSB); 181 } 182 183 static int wdt_update_timeout(unsigned int t) 184 { 185 int ret; 186 187 ret = superio_enter(); 188 if (ret) 189 return ret; 190 191 superio_select(GPIO); 192 _wdt_update_timeout(t); 193 superio_exit(); 194 195 return 0; 196 } 197 198 static int wdt_round_time(int t) 199 { 200 t += 59; 201 t -= t % 60; 202 return t; 203 } 204 205 /* watchdog timer handling */ 206 207 static int wdt_start(struct watchdog_device *wdd) 208 { 209 return wdt_update_timeout(wdd->timeout); 210 } 211 212 static int wdt_stop(struct watchdog_device *wdd) 213 { 214 return wdt_update_timeout(0); 215 } 216 217 /** 218 * wdt_set_timeout - set a new timeout value with watchdog ioctl 219 * @t: timeout value in seconds 220 * 221 * The hardware device has a 8 or 16 bit watchdog timer (depends on 222 * chip version) that can be configured to count seconds or minutes. 223 * 224 * Used within WDIOC_SETTIMEOUT watchdog device ioctl. 225 */ 226 227 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 228 { 229 int ret = 0; 230 231 if (t > max_units) 232 t = wdt_round_time(t); 233 234 wdd->timeout = t; 235 236 if (watchdog_hw_running(wdd)) 237 ret = wdt_update_timeout(t); 238 239 return ret; 240 } 241 242 static const struct watchdog_info ident = { 243 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 244 .firmware_version = 1, 245 .identity = WATCHDOG_NAME, 246 }; 247 248 static const struct watchdog_ops wdt_ops = { 249 .owner = THIS_MODULE, 250 .start = wdt_start, 251 .stop = wdt_stop, 252 .set_timeout = wdt_set_timeout, 253 }; 254 255 static struct watchdog_device wdt_dev = { 256 .info = &ident, 257 .ops = &wdt_ops, 258 .min_timeout = 1, 259 }; 260 261 static int __init it87_wdt_init(void) 262 { 263 u8 chip_rev; 264 int rc; 265 266 rc = superio_enter(); 267 if (rc) 268 return rc; 269 270 chip_type = superio_inw(CHIPID); 271 chip_rev = superio_inb(CHIPREV) & 0x0f; 272 superio_exit(); 273 274 switch (chip_type) { 275 case IT8702_ID: 276 max_units = 255; 277 break; 278 case IT8712_ID: 279 max_units = (chip_rev < 8) ? 255 : 65535; 280 break; 281 case IT8716_ID: 282 case IT8726_ID: 283 max_units = 65535; 284 break; 285 case IT8607_ID: 286 case IT8620_ID: 287 case IT8622_ID: 288 case IT8625_ID: 289 case IT8628_ID: 290 case IT8655_ID: 291 case IT8665_ID: 292 case IT8686_ID: 293 case IT8718_ID: 294 case IT8720_ID: 295 case IT8721_ID: 296 case IT8728_ID: 297 case IT8783_ID: 298 case IT8786_ID: 299 max_units = 65535; 300 break; 301 case IT8705_ID: 302 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n", 303 chip_type, chip_rev); 304 return -ENODEV; 305 case NO_DEV_ID: 306 pr_err("no device\n"); 307 return -ENODEV; 308 default: 309 pr_err("Unknown Chip found, Chip %04x Revision %04x\n", 310 chip_type, chip_rev); 311 return -ENODEV; 312 } 313 314 rc = superio_enter(); 315 if (rc) 316 return rc; 317 318 superio_select(GPIO); 319 superio_outb(WDT_TOV1, WDTCFG); 320 superio_outb(0x00, WDTCTRL); 321 superio_exit(); 322 323 if (timeout < 1 || timeout > max_units * 60) { 324 timeout = DEFAULT_TIMEOUT; 325 pr_warn("Timeout value out of range, use default %d sec\n", 326 DEFAULT_TIMEOUT); 327 } 328 329 if (timeout > max_units) 330 timeout = wdt_round_time(timeout); 331 332 wdt_dev.timeout = timeout; 333 wdt_dev.max_timeout = max_units * 60; 334 335 watchdog_stop_on_reboot(&wdt_dev); 336 rc = watchdog_register_device(&wdt_dev); 337 if (rc) { 338 pr_err("Cannot register watchdog device (err=%d)\n", rc); 339 return rc; 340 } 341 342 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 343 chip_type, chip_rev, timeout, nowayout, testmode); 344 345 return 0; 346 } 347 348 static void __exit it87_wdt_exit(void) 349 { 350 watchdog_unregister_device(&wdt_dev); 351 } 352 353 module_init(it87_wdt_init); 354 module_exit(it87_wdt_exit); 355 356 MODULE_AUTHOR("Oliver Schuster"); 357 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O"); 358 MODULE_LICENSE("GPL"); 359