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 /* Internal function, should be called after superio_select(GPIO) */ 156 static void _wdt_update_timeout(unsigned int t) 157 { 158 unsigned char cfg = WDT_KRST; 159 160 if (testmode) 161 cfg = 0; 162 163 if (t <= max_units) 164 cfg |= WDT_TOV1; 165 else 166 t /= 60; 167 168 if (chip_type != IT8721_ID) 169 cfg |= WDT_PWROK; 170 171 superio_outb(cfg, WDTCFG); 172 superio_outb(t, WDTVALLSB); 173 if (max_units > 255) 174 superio_outb(t >> 8, WDTVALMSB); 175 } 176 177 static int wdt_update_timeout(unsigned int t) 178 { 179 int ret; 180 181 ret = superio_enter(); 182 if (ret) 183 return ret; 184 185 superio_select(GPIO); 186 _wdt_update_timeout(t); 187 superio_exit(); 188 189 return 0; 190 } 191 192 static int wdt_round_time(int t) 193 { 194 t += 59; 195 t -= t % 60; 196 return t; 197 } 198 199 /* watchdog timer handling */ 200 201 static int wdt_start(struct watchdog_device *wdd) 202 { 203 return wdt_update_timeout(wdd->timeout); 204 } 205 206 static int wdt_stop(struct watchdog_device *wdd) 207 { 208 return wdt_update_timeout(0); 209 } 210 211 /** 212 * wdt_set_timeout - set a new timeout value with watchdog ioctl 213 * @t: timeout value in seconds 214 * 215 * The hardware device has a 8 or 16 bit watchdog timer (depends on 216 * chip version) that can be configured to count seconds or minutes. 217 * 218 * Used within WDIOC_SETTIMEOUT watchdog device ioctl. 219 */ 220 221 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 222 { 223 int ret = 0; 224 225 if (t > max_units) 226 t = wdt_round_time(t); 227 228 wdd->timeout = t; 229 230 if (watchdog_hw_running(wdd)) 231 ret = wdt_update_timeout(t); 232 233 return ret; 234 } 235 236 static const struct watchdog_info ident = { 237 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 238 .firmware_version = 1, 239 .identity = WATCHDOG_NAME, 240 }; 241 242 static const struct watchdog_ops wdt_ops = { 243 .owner = THIS_MODULE, 244 .start = wdt_start, 245 .stop = wdt_stop, 246 .set_timeout = wdt_set_timeout, 247 }; 248 249 static struct watchdog_device wdt_dev = { 250 .info = &ident, 251 .ops = &wdt_ops, 252 .min_timeout = 1, 253 }; 254 255 static int __init it87_wdt_init(void) 256 { 257 u8 chip_rev; 258 int rc; 259 260 rc = superio_enter(); 261 if (rc) 262 return rc; 263 264 chip_type = superio_inw(CHIPID); 265 chip_rev = superio_inb(CHIPREV) & 0x0f; 266 superio_exit(); 267 268 switch (chip_type) { 269 case IT8702_ID: 270 max_units = 255; 271 break; 272 case IT8712_ID: 273 max_units = (chip_rev < 8) ? 255 : 65535; 274 break; 275 case IT8716_ID: 276 case IT8726_ID: 277 max_units = 65535; 278 break; 279 case IT8607_ID: 280 case IT8620_ID: 281 case IT8622_ID: 282 case IT8625_ID: 283 case IT8628_ID: 284 case IT8655_ID: 285 case IT8665_ID: 286 case IT8686_ID: 287 case IT8718_ID: 288 case IT8720_ID: 289 case IT8721_ID: 290 case IT8728_ID: 291 case IT8772_ID: 292 case IT8783_ID: 293 case IT8784_ID: 294 case IT8786_ID: 295 max_units = 65535; 296 break; 297 case IT8705_ID: 298 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n", 299 chip_type, chip_rev); 300 return -ENODEV; 301 case NO_DEV_ID: 302 pr_err("no device\n"); 303 return -ENODEV; 304 default: 305 pr_err("Unknown Chip found, Chip %04x Revision %04x\n", 306 chip_type, chip_rev); 307 return -ENODEV; 308 } 309 310 rc = superio_enter(); 311 if (rc) 312 return rc; 313 314 superio_select(GPIO); 315 superio_outb(WDT_TOV1, WDTCFG); 316 superio_outb(0x00, WDTCTRL); 317 superio_exit(); 318 319 if (timeout < 1 || timeout > max_units * 60) { 320 timeout = DEFAULT_TIMEOUT; 321 pr_warn("Timeout value out of range, use default %d sec\n", 322 DEFAULT_TIMEOUT); 323 } 324 325 if (timeout > max_units) 326 timeout = wdt_round_time(timeout); 327 328 wdt_dev.timeout = timeout; 329 wdt_dev.max_timeout = max_units * 60; 330 331 watchdog_stop_on_reboot(&wdt_dev); 332 rc = watchdog_register_device(&wdt_dev); 333 if (rc) { 334 pr_err("Cannot register watchdog device (err=%d)\n", rc); 335 return rc; 336 } 337 338 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 339 chip_type, chip_rev, timeout, nowayout, testmode); 340 341 return 0; 342 } 343 344 static void __exit it87_wdt_exit(void) 345 { 346 watchdog_unregister_device(&wdt_dev); 347 } 348 349 module_init(it87_wdt_init); 350 module_exit(it87_wdt_exit); 351 352 MODULE_AUTHOR("Oliver Schuster"); 353 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O"); 354 MODULE_LICENSE("GPL"); 355