1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip 4 * 5 * (c) Copyright 2005 Jose Goncalves <jose.goncalves@inov.pt> 6 * 7 * Based on w83877f_wdt.c by Scott Jennings, 8 * and wdt977.c by Woody Suwalski 9 * 10 * ----------------------- 11 */ 12 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15 #include <linux/module.h> 16 #include <linux/moduleparam.h> 17 #include <linux/types.h> 18 #include <linux/kernel.h> 19 #include <linux/fs.h> 20 #include <linux/miscdevice.h> 21 #include <linux/init.h> 22 #include <linux/ioport.h> 23 #include <linux/watchdog.h> 24 #include <linux/notifier.h> 25 #include <linux/reboot.h> 26 #include <linux/uaccess.h> 27 #include <linux/io.h> 28 29 30 #define WATCHDOG_VERSION "1.00" 31 #define WATCHDOG_NAME "W83977F WDT" 32 33 #define IO_INDEX_PORT 0x3F0 34 #define IO_DATA_PORT (IO_INDEX_PORT+1) 35 36 #define UNLOCK_DATA 0x87 37 #define LOCK_DATA 0xAA 38 #define DEVICE_REGISTER 0x07 39 40 #define DEFAULT_TIMEOUT 45 /* default timeout in seconds */ 41 42 static int timeout = DEFAULT_TIMEOUT; 43 static int timeoutW; /* timeout in watchdog counter units */ 44 static unsigned long timer_alive; 45 static int testmode; 46 static char expect_close; 47 static DEFINE_SPINLOCK(spinlock); 48 49 module_param(timeout, int, 0); 50 MODULE_PARM_DESC(timeout, 51 "Watchdog timeout in seconds (15..7635), default=" 52 __MODULE_STRING(DEFAULT_TIMEOUT) ")"); 53 module_param(testmode, int, 0); 54 MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0"); 55 56 static bool nowayout = WATCHDOG_NOWAYOUT; 57 module_param(nowayout, bool, 0); 58 MODULE_PARM_DESC(nowayout, 59 "Watchdog cannot be stopped once started (default=" 60 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 61 62 /* 63 * Start the watchdog 64 */ 65 66 static int wdt_start(void) 67 { 68 unsigned long flags; 69 70 spin_lock_irqsave(&spinlock, flags); 71 72 /* Unlock the SuperIO chip */ 73 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 74 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 75 76 /* 77 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4. 78 * F2 has the timeout in watchdog counter units. 79 * F3 is set to enable watchdog LED blink at timeout. 80 * F4 is used to just clear the TIMEOUT'ed state (bit 0). 81 */ 82 outb_p(DEVICE_REGISTER, IO_INDEX_PORT); 83 outb_p(0x08, IO_DATA_PORT); 84 outb_p(0xF2, IO_INDEX_PORT); 85 outb_p(timeoutW, IO_DATA_PORT); 86 outb_p(0xF3, IO_INDEX_PORT); 87 outb_p(0x08, IO_DATA_PORT); 88 outb_p(0xF4, IO_INDEX_PORT); 89 outb_p(0x00, IO_DATA_PORT); 90 91 /* Set device Aux2 active */ 92 outb_p(0x30, IO_INDEX_PORT); 93 outb_p(0x01, IO_DATA_PORT); 94 95 /* 96 * Select device Aux1 (dev=7) to set GP16 as the watchdog output 97 * (in reg E6) and GP13 as the watchdog LED output (in reg E3). 98 * Map GP16 at pin 119. 99 * In test mode watch the bit 0 on F4 to indicate "triggered" or 100 * check watchdog LED on SBC. 101 */ 102 outb_p(DEVICE_REGISTER, IO_INDEX_PORT); 103 outb_p(0x07, IO_DATA_PORT); 104 if (!testmode) { 105 unsigned pin_map; 106 107 outb_p(0xE6, IO_INDEX_PORT); 108 outb_p(0x0A, IO_DATA_PORT); 109 outb_p(0x2C, IO_INDEX_PORT); 110 pin_map = inb_p(IO_DATA_PORT); 111 pin_map |= 0x10; 112 pin_map &= ~(0x20); 113 outb_p(0x2C, IO_INDEX_PORT); 114 outb_p(pin_map, IO_DATA_PORT); 115 } 116 outb_p(0xE3, IO_INDEX_PORT); 117 outb_p(0x08, IO_DATA_PORT); 118 119 /* Set device Aux1 active */ 120 outb_p(0x30, IO_INDEX_PORT); 121 outb_p(0x01, IO_DATA_PORT); 122 123 /* Lock the SuperIO chip */ 124 outb_p(LOCK_DATA, IO_INDEX_PORT); 125 126 spin_unlock_irqrestore(&spinlock, flags); 127 128 pr_info("activated\n"); 129 130 return 0; 131 } 132 133 /* 134 * Stop the watchdog 135 */ 136 137 static int wdt_stop(void) 138 { 139 unsigned long flags; 140 141 spin_lock_irqsave(&spinlock, flags); 142 143 /* Unlock the SuperIO chip */ 144 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 145 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 146 147 /* 148 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4. 149 * F2 is reset to its default value (watchdog timer disabled). 150 * F3 is reset to its default state. 151 * F4 clears the TIMEOUT'ed state (bit 0) - back to default. 152 */ 153 outb_p(DEVICE_REGISTER, IO_INDEX_PORT); 154 outb_p(0x08, IO_DATA_PORT); 155 outb_p(0xF2, IO_INDEX_PORT); 156 outb_p(0xFF, IO_DATA_PORT); 157 outb_p(0xF3, IO_INDEX_PORT); 158 outb_p(0x00, IO_DATA_PORT); 159 outb_p(0xF4, IO_INDEX_PORT); 160 outb_p(0x00, IO_DATA_PORT); 161 outb_p(0xF2, IO_INDEX_PORT); 162 outb_p(0x00, IO_DATA_PORT); 163 164 /* 165 * Select device Aux1 (dev=7) to set GP16 (in reg E6) and 166 * Gp13 (in reg E3) as inputs. 167 */ 168 outb_p(DEVICE_REGISTER, IO_INDEX_PORT); 169 outb_p(0x07, IO_DATA_PORT); 170 if (!testmode) { 171 outb_p(0xE6, IO_INDEX_PORT); 172 outb_p(0x01, IO_DATA_PORT); 173 } 174 outb_p(0xE3, IO_INDEX_PORT); 175 outb_p(0x01, IO_DATA_PORT); 176 177 /* Lock the SuperIO chip */ 178 outb_p(LOCK_DATA, IO_INDEX_PORT); 179 180 spin_unlock_irqrestore(&spinlock, flags); 181 182 pr_info("shutdown\n"); 183 184 return 0; 185 } 186 187 /* 188 * Send a keepalive ping to the watchdog 189 * This is done by simply re-writing the timeout to reg. 0xF2 190 */ 191 192 static int wdt_keepalive(void) 193 { 194 unsigned long flags; 195 196 spin_lock_irqsave(&spinlock, flags); 197 198 /* Unlock the SuperIO chip */ 199 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 200 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 201 202 /* Select device Aux2 (device=8) to kick watchdog reg F2 */ 203 outb_p(DEVICE_REGISTER, IO_INDEX_PORT); 204 outb_p(0x08, IO_DATA_PORT); 205 outb_p(0xF2, IO_INDEX_PORT); 206 outb_p(timeoutW, IO_DATA_PORT); 207 208 /* Lock the SuperIO chip */ 209 outb_p(LOCK_DATA, IO_INDEX_PORT); 210 211 spin_unlock_irqrestore(&spinlock, flags); 212 213 return 0; 214 } 215 216 /* 217 * Set the watchdog timeout value 218 */ 219 220 static int wdt_set_timeout(int t) 221 { 222 unsigned int tmrval; 223 224 /* 225 * Convert seconds to watchdog counter time units, rounding up. 226 * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup 227 * value. This information is supplied in the PCM-5335 manual and was 228 * checked by me on a real board. This is a bit strange because W83977f 229 * datasheet says counter unit is in minutes! 230 */ 231 if (t < 15) 232 return -EINVAL; 233 234 tmrval = ((t + 15) + 29) / 30; 235 236 if (tmrval > 255) 237 return -EINVAL; 238 239 /* 240 * timeout is the timeout in seconds, 241 * timeoutW is the timeout in watchdog counter units. 242 */ 243 timeoutW = tmrval; 244 timeout = (timeoutW * 30) - 15; 245 return 0; 246 } 247 248 /* 249 * Get the watchdog status 250 */ 251 252 static int wdt_get_status(int *status) 253 { 254 int new_status; 255 unsigned long flags; 256 257 spin_lock_irqsave(&spinlock, flags); 258 259 /* Unlock the SuperIO chip */ 260 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 261 outb_p(UNLOCK_DATA, IO_INDEX_PORT); 262 263 /* Select device Aux2 (device=8) to read watchdog reg F4 */ 264 outb_p(DEVICE_REGISTER, IO_INDEX_PORT); 265 outb_p(0x08, IO_DATA_PORT); 266 outb_p(0xF4, IO_INDEX_PORT); 267 new_status = inb_p(IO_DATA_PORT); 268 269 /* Lock the SuperIO chip */ 270 outb_p(LOCK_DATA, IO_INDEX_PORT); 271 272 spin_unlock_irqrestore(&spinlock, flags); 273 274 *status = 0; 275 if (new_status & 1) 276 *status |= WDIOF_CARDRESET; 277 278 return 0; 279 } 280 281 282 /* 283 * /dev/watchdog handling 284 */ 285 286 static int wdt_open(struct inode *inode, struct file *file) 287 { 288 /* If the watchdog is alive we don't need to start it again */ 289 if (test_and_set_bit(0, &timer_alive)) 290 return -EBUSY; 291 292 if (nowayout) 293 __module_get(THIS_MODULE); 294 295 wdt_start(); 296 return stream_open(inode, file); 297 } 298 299 static int wdt_release(struct inode *inode, struct file *file) 300 { 301 /* 302 * Shut off the timer. 303 * Lock it in if it's a module and we set nowayout 304 */ 305 if (expect_close == 42) { 306 wdt_stop(); 307 clear_bit(0, &timer_alive); 308 } else { 309 wdt_keepalive(); 310 pr_crit("unexpected close, not stopping watchdog!\n"); 311 } 312 expect_close = 0; 313 return 0; 314 } 315 316 /* 317 * wdt_write: 318 * @file: file handle to the watchdog 319 * @buf: buffer to write (unused as data does not matter here 320 * @count: count of bytes 321 * @ppos: pointer to the position to write. No seeks allowed 322 * 323 * A write to a watchdog device is defined as a keepalive signal. Any 324 * write of data will do, as we we don't define content meaning. 325 */ 326 327 static ssize_t wdt_write(struct file *file, const char __user *buf, 328 size_t count, loff_t *ppos) 329 { 330 /* See if we got the magic character 'V' and reload the timer */ 331 if (count) { 332 if (!nowayout) { 333 size_t ofs; 334 335 /* note: just in case someone wrote the 336 magic character long ago */ 337 expect_close = 0; 338 339 /* scan to see whether or not we got the 340 magic character */ 341 for (ofs = 0; ofs != count; ofs++) { 342 char c; 343 if (get_user(c, buf + ofs)) 344 return -EFAULT; 345 if (c == 'V') 346 expect_close = 42; 347 } 348 } 349 350 /* someone wrote to us, we should restart timer */ 351 wdt_keepalive(); 352 } 353 return count; 354 } 355 356 /* 357 * wdt_ioctl: 358 * @inode: inode of the device 359 * @file: file handle to the device 360 * @cmd: watchdog command 361 * @arg: argument pointer 362 * 363 * The watchdog API defines a common set of functions for all watchdogs 364 * according to their available features. 365 */ 366 367 static const struct watchdog_info ident = { 368 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 369 .firmware_version = 1, 370 .identity = WATCHDOG_NAME, 371 }; 372 373 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 374 { 375 int status; 376 int new_options, retval = -EINVAL; 377 int new_timeout; 378 union { 379 struct watchdog_info __user *ident; 380 int __user *i; 381 } uarg; 382 383 uarg.i = (int __user *)arg; 384 385 switch (cmd) { 386 case WDIOC_GETSUPPORT: 387 return copy_to_user(uarg.ident, &ident, 388 sizeof(ident)) ? -EFAULT : 0; 389 390 case WDIOC_GETSTATUS: 391 wdt_get_status(&status); 392 return put_user(status, uarg.i); 393 394 case WDIOC_GETBOOTSTATUS: 395 return put_user(0, uarg.i); 396 397 case WDIOC_SETOPTIONS: 398 if (get_user(new_options, uarg.i)) 399 return -EFAULT; 400 401 if (new_options & WDIOS_DISABLECARD) { 402 wdt_stop(); 403 retval = 0; 404 } 405 406 if (new_options & WDIOS_ENABLECARD) { 407 wdt_start(); 408 retval = 0; 409 } 410 411 return retval; 412 413 case WDIOC_KEEPALIVE: 414 wdt_keepalive(); 415 return 0; 416 417 case WDIOC_SETTIMEOUT: 418 if (get_user(new_timeout, uarg.i)) 419 return -EFAULT; 420 421 if (wdt_set_timeout(new_timeout)) 422 return -EINVAL; 423 424 wdt_keepalive(); 425 fallthrough; 426 427 case WDIOC_GETTIMEOUT: 428 return put_user(timeout, uarg.i); 429 430 default: 431 return -ENOTTY; 432 433 } 434 } 435 436 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 437 void *unused) 438 { 439 if (code == SYS_DOWN || code == SYS_HALT) 440 wdt_stop(); 441 return NOTIFY_DONE; 442 } 443 444 static const struct file_operations wdt_fops = { 445 .owner = THIS_MODULE, 446 .llseek = no_llseek, 447 .write = wdt_write, 448 .unlocked_ioctl = wdt_ioctl, 449 .compat_ioctl = compat_ptr_ioctl, 450 .open = wdt_open, 451 .release = wdt_release, 452 }; 453 454 static struct miscdevice wdt_miscdev = { 455 .minor = WATCHDOG_MINOR, 456 .name = "watchdog", 457 .fops = &wdt_fops, 458 }; 459 460 static struct notifier_block wdt_notifier = { 461 .notifier_call = wdt_notify_sys, 462 }; 463 464 static int __init w83977f_wdt_init(void) 465 { 466 int rc; 467 468 pr_info("driver v%s\n", WATCHDOG_VERSION); 469 470 /* 471 * Check that the timeout value is within it's range; 472 * if not reset to the default 473 */ 474 if (wdt_set_timeout(timeout)) { 475 wdt_set_timeout(DEFAULT_TIMEOUT); 476 pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n", 477 DEFAULT_TIMEOUT); 478 } 479 480 if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) { 481 pr_err("I/O address 0x%04x already in use\n", IO_INDEX_PORT); 482 rc = -EIO; 483 goto err_out; 484 } 485 486 rc = register_reboot_notifier(&wdt_notifier); 487 if (rc) { 488 pr_err("cannot register reboot notifier (err=%d)\n", rc); 489 goto err_out_region; 490 } 491 492 rc = misc_register(&wdt_miscdev); 493 if (rc) { 494 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 495 wdt_miscdev.minor, rc); 496 goto err_out_reboot; 497 } 498 499 pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n", 500 timeout, nowayout, testmode); 501 502 return 0; 503 504 err_out_reboot: 505 unregister_reboot_notifier(&wdt_notifier); 506 err_out_region: 507 release_region(IO_INDEX_PORT, 2); 508 err_out: 509 return rc; 510 } 511 512 static void __exit w83977f_wdt_exit(void) 513 { 514 wdt_stop(); 515 misc_deregister(&wdt_miscdev); 516 unregister_reboot_notifier(&wdt_notifier); 517 release_region(IO_INDEX_PORT, 2); 518 } 519 520 module_init(w83977f_wdt_init); 521 module_exit(w83977f_wdt_exit); 522 523 MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>"); 524 MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip"); 525 MODULE_LICENSE("GPL"); 526