1 /* 2 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x 3 * 4 * This code is based on wdt.c with original copyright. 5 * 6 * (C) Copyright 2006 Sven Anders, <anders@anduras.de> 7 * and Marcus Junker, <junker@anduras.de> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 * 14 * Neither Sven Anders, Marcus Junker nor ANDURAS AG 15 * admit liability nor provide warranty for any of this software. 16 * This material is provided "AS-IS" and at no charge. 17 * 18 * Release 1.1 19 */ 20 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 22 23 #include <linux/module.h> 24 #include <linux/types.h> 25 #include <linux/miscdevice.h> 26 #include <linux/watchdog.h> 27 #include <linux/ioport.h> 28 #include <linux/delay.h> 29 #include <linux/notifier.h> 30 #include <linux/fs.h> 31 #include <linux/reboot.h> 32 #include <linux/init.h> 33 #include <linux/spinlock.h> 34 #include <linux/moduleparam.h> 35 #include <linux/io.h> 36 #include <linux/uaccess.h> 37 38 39 /* #define DEBUG 1 */ 40 41 #define DEFAULT_TIMEOUT 1 /* 1 minute */ 42 #define MAX_TIMEOUT 255 43 44 #define VERSION "1.1" 45 #define MODNAME "pc87413 WDT" 46 #define DPFX MODNAME " - DEBUG: " 47 48 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */ 49 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1) 50 #define SWC_LDN 0x04 51 #define SIOCFG2 0x22 /* Serial IO register */ 52 #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */ 53 #define WDTO 0x11 /* Watchdog timeout register */ 54 #define WDCFG 0x12 /* Watchdog config register */ 55 56 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */ 57 58 static int io = IO_DEFAULT; 59 static int swc_base_addr = -1; 60 61 static int timeout = DEFAULT_TIMEOUT; /* timeout value */ 62 static unsigned long timer_enabled; /* is the timer enabled? */ 63 64 static char expect_close; /* is the close expected? */ 65 66 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */ 67 68 static bool nowayout = WATCHDOG_NOWAYOUT; 69 70 /* -- Low level function ----------------------------------------*/ 71 72 /* Select pins for Watchdog output */ 73 74 static inline void pc87413_select_wdt_out(void) 75 { 76 unsigned int cr_data = 0; 77 78 /* Step 1: Select multiple pin,pin55,as WDT output */ 79 80 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 81 82 cr_data = inb(WDT_DATA_IO_PORT); 83 84 cr_data |= 0x80; /* Set Bit7 to 1*/ 85 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 86 87 outb_p(cr_data, WDT_DATA_IO_PORT); 88 89 #ifdef DEBUG 90 pr_info(DPFX 91 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n", 92 cr_data); 93 #endif 94 } 95 96 /* Enable SWC functions */ 97 98 static inline void pc87413_enable_swc(void) 99 { 100 unsigned int cr_data = 0; 101 102 /* Step 2: Enable SWC functions */ 103 104 outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */ 105 outb_p(SWC_LDN, WDT_DATA_IO_PORT); 106 107 outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */ 108 cr_data = inb(WDT_DATA_IO_PORT); 109 cr_data |= 0x01; /* Set Bit0 to 1 */ 110 outb_p(0x30, WDT_INDEX_IO_PORT); 111 outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */ 112 113 #ifdef DEBUG 114 pr_info(DPFX "pc87413 - Enable SWC functions\n"); 115 #endif 116 } 117 118 /* Read SWC I/O base address */ 119 120 static void pc87413_get_swc_base_addr(void) 121 { 122 unsigned char addr_l, addr_h = 0; 123 124 /* Step 3: Read SWC I/O Base Address */ 125 126 outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */ 127 addr_h = inb(WDT_DATA_IO_PORT); 128 129 outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */ 130 131 addr_l = inb(WDT_DATA_IO_PORT); 132 133 swc_base_addr = (addr_h << 8) + addr_l; 134 #ifdef DEBUG 135 pr_info(DPFX 136 "Read SWC I/O Base Address: low %d, high %d, res %d\n", 137 addr_l, addr_h, swc_base_addr); 138 #endif 139 } 140 141 /* Select Bank 3 of SWC */ 142 143 static inline void pc87413_swc_bank3(void) 144 { 145 /* Step 4: Select Bank3 of SWC */ 146 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f); 147 #ifdef DEBUG 148 pr_info(DPFX "Select Bank3 of SWC\n"); 149 #endif 150 } 151 152 /* Set watchdog timeout to x minutes */ 153 154 static inline void pc87413_programm_wdto(char pc87413_time) 155 { 156 /* Step 5: Programm WDTO, Twd. */ 157 outb_p(pc87413_time, swc_base_addr + WDTO); 158 #ifdef DEBUG 159 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time); 160 #endif 161 } 162 163 /* Enable WDEN */ 164 165 static inline void pc87413_enable_wden(void) 166 { 167 /* Step 6: Enable WDEN */ 168 outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL); 169 #ifdef DEBUG 170 pr_info(DPFX "Enable WDEN\n"); 171 #endif 172 } 173 174 /* Enable SW_WD_TREN */ 175 static inline void pc87413_enable_sw_wd_tren(void) 176 { 177 /* Enable SW_WD_TREN */ 178 outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG); 179 #ifdef DEBUG 180 pr_info(DPFX "Enable SW_WD_TREN\n"); 181 #endif 182 } 183 184 /* Disable SW_WD_TREN */ 185 186 static inline void pc87413_disable_sw_wd_tren(void) 187 { 188 /* Disable SW_WD_TREN */ 189 outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG); 190 #ifdef DEBUG 191 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n"); 192 #endif 193 } 194 195 /* Enable SW_WD_TRG */ 196 197 static inline void pc87413_enable_sw_wd_trg(void) 198 { 199 /* Enable SW_WD_TRG */ 200 outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL); 201 #ifdef DEBUG 202 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n"); 203 #endif 204 } 205 206 /* Disable SW_WD_TRG */ 207 208 static inline void pc87413_disable_sw_wd_trg(void) 209 { 210 /* Disable SW_WD_TRG */ 211 outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL); 212 #ifdef DEBUG 213 pr_info(DPFX "Disable SW_WD_TRG\n"); 214 #endif 215 } 216 217 /* -- Higher level functions ------------------------------------*/ 218 219 /* Enable the watchdog */ 220 221 static void pc87413_enable(void) 222 { 223 spin_lock(&io_lock); 224 225 pc87413_swc_bank3(); 226 pc87413_programm_wdto(timeout); 227 pc87413_enable_wden(); 228 pc87413_enable_sw_wd_tren(); 229 pc87413_enable_sw_wd_trg(); 230 231 spin_unlock(&io_lock); 232 } 233 234 /* Disable the watchdog */ 235 236 static void pc87413_disable(void) 237 { 238 spin_lock(&io_lock); 239 240 pc87413_swc_bank3(); 241 pc87413_disable_sw_wd_tren(); 242 pc87413_disable_sw_wd_trg(); 243 pc87413_programm_wdto(0); 244 245 spin_unlock(&io_lock); 246 } 247 248 /* Refresh the watchdog */ 249 250 static void pc87413_refresh(void) 251 { 252 spin_lock(&io_lock); 253 254 pc87413_swc_bank3(); 255 pc87413_disable_sw_wd_tren(); 256 pc87413_disable_sw_wd_trg(); 257 pc87413_programm_wdto(timeout); 258 pc87413_enable_wden(); 259 pc87413_enable_sw_wd_tren(); 260 pc87413_enable_sw_wd_trg(); 261 262 spin_unlock(&io_lock); 263 } 264 265 /* -- File operations -------------------------------------------*/ 266 267 /** 268 * pc87413_open: 269 * @inode: inode of device 270 * @file: file handle to device 271 * 272 */ 273 274 static int pc87413_open(struct inode *inode, struct file *file) 275 { 276 /* /dev/watchdog can only be opened once */ 277 278 if (test_and_set_bit(0, &timer_enabled)) 279 return -EBUSY; 280 281 if (nowayout) 282 __module_get(THIS_MODULE); 283 284 /* Reload and activate timer */ 285 pc87413_refresh(); 286 287 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout); 288 289 return stream_open(inode, file); 290 } 291 292 /** 293 * pc87413_release: 294 * @inode: inode to board 295 * @file: file handle to board 296 * 297 * The watchdog has a configurable API. There is a religious dispute 298 * between people who want their watchdog to be able to shut down and 299 * those who want to be sure if the watchdog manager dies the machine 300 * reboots. In the former case we disable the counters, in the latter 301 * case you have to open it again very soon. 302 */ 303 304 static int pc87413_release(struct inode *inode, struct file *file) 305 { 306 /* Shut off the timer. */ 307 308 if (expect_close == 42) { 309 pc87413_disable(); 310 pr_info("Watchdog disabled, sleeping again...\n"); 311 } else { 312 pr_crit("Unexpected close, not stopping watchdog!\n"); 313 pc87413_refresh(); 314 } 315 clear_bit(0, &timer_enabled); 316 expect_close = 0; 317 return 0; 318 } 319 320 /** 321 * pc87413_status: 322 * 323 * return, if the watchdog is enabled (timeout is set...) 324 */ 325 326 327 static int pc87413_status(void) 328 { 329 return 0; /* currently not supported */ 330 } 331 332 /** 333 * pc87413_write: 334 * @file: file handle to the watchdog 335 * @data: data buffer to write 336 * @len: length in bytes 337 * @ppos: pointer to the position to write. No seeks allowed 338 * 339 * A write to a watchdog device is defined as a keepalive signal. Any 340 * write of data will do, as we we don't define content meaning. 341 */ 342 343 static ssize_t pc87413_write(struct file *file, const char __user *data, 344 size_t len, loff_t *ppos) 345 { 346 /* See if we got the magic character 'V' and reload the timer */ 347 if (len) { 348 if (!nowayout) { 349 size_t i; 350 351 /* reset expect flag */ 352 expect_close = 0; 353 354 /* scan to see whether or not we got the 355 magic character */ 356 for (i = 0; i != len; i++) { 357 char c; 358 if (get_user(c, data + i)) 359 return -EFAULT; 360 if (c == 'V') 361 expect_close = 42; 362 } 363 } 364 365 /* someone wrote to us, we should reload the timer */ 366 pc87413_refresh(); 367 } 368 return len; 369 } 370 371 /** 372 * pc87413_ioctl: 373 * @file: file handle to the device 374 * @cmd: watchdog command 375 * @arg: argument pointer 376 * 377 * The watchdog API defines a common set of functions for all watchdogs 378 * according to their available features. We only actually usefully support 379 * querying capabilities and current status. 380 */ 381 382 static long pc87413_ioctl(struct file *file, unsigned int cmd, 383 unsigned long arg) 384 { 385 int new_timeout; 386 387 union { 388 struct watchdog_info __user *ident; 389 int __user *i; 390 } uarg; 391 392 static const struct watchdog_info ident = { 393 .options = WDIOF_KEEPALIVEPING | 394 WDIOF_SETTIMEOUT | 395 WDIOF_MAGICCLOSE, 396 .firmware_version = 1, 397 .identity = "PC87413(HF/F) watchdog", 398 }; 399 400 uarg.i = (int __user *)arg; 401 402 switch (cmd) { 403 case WDIOC_GETSUPPORT: 404 return copy_to_user(uarg.ident, &ident, 405 sizeof(ident)) ? -EFAULT : 0; 406 case WDIOC_GETSTATUS: 407 return put_user(pc87413_status(), uarg.i); 408 case WDIOC_GETBOOTSTATUS: 409 return put_user(0, uarg.i); 410 case WDIOC_SETOPTIONS: 411 { 412 int options, retval = -EINVAL; 413 if (get_user(options, uarg.i)) 414 return -EFAULT; 415 if (options & WDIOS_DISABLECARD) { 416 pc87413_disable(); 417 retval = 0; 418 } 419 if (options & WDIOS_ENABLECARD) { 420 pc87413_enable(); 421 retval = 0; 422 } 423 return retval; 424 } 425 case WDIOC_KEEPALIVE: 426 pc87413_refresh(); 427 #ifdef DEBUG 428 pr_info(DPFX "keepalive\n"); 429 #endif 430 return 0; 431 case WDIOC_SETTIMEOUT: 432 if (get_user(new_timeout, uarg.i)) 433 return -EFAULT; 434 /* the API states this is given in secs */ 435 new_timeout /= 60; 436 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 437 return -EINVAL; 438 timeout = new_timeout; 439 pc87413_refresh(); 440 /* fall through - and return the new timeout... */ 441 case WDIOC_GETTIMEOUT: 442 new_timeout = timeout * 60; 443 return put_user(new_timeout, uarg.i); 444 default: 445 return -ENOTTY; 446 } 447 } 448 449 /* -- Notifier funtions -----------------------------------------*/ 450 451 /** 452 * notify_sys: 453 * @this: our notifier block 454 * @code: the event being reported 455 * @unused: unused 456 * 457 * Our notifier is called on system shutdowns. We want to turn the card 458 * off at reboot otherwise the machine will reboot again during memory 459 * test or worse yet during the following fsck. This would suck, in fact 460 * trust me - if it happens it does suck. 461 */ 462 463 static int pc87413_notify_sys(struct notifier_block *this, 464 unsigned long code, 465 void *unused) 466 { 467 if (code == SYS_DOWN || code == SYS_HALT) 468 /* Turn the card off */ 469 pc87413_disable(); 470 return NOTIFY_DONE; 471 } 472 473 /* -- Module's structures ---------------------------------------*/ 474 475 static const struct file_operations pc87413_fops = { 476 .owner = THIS_MODULE, 477 .llseek = no_llseek, 478 .write = pc87413_write, 479 .unlocked_ioctl = pc87413_ioctl, 480 .open = pc87413_open, 481 .release = pc87413_release, 482 }; 483 484 static struct notifier_block pc87413_notifier = { 485 .notifier_call = pc87413_notify_sys, 486 }; 487 488 static struct miscdevice pc87413_miscdev = { 489 .minor = WATCHDOG_MINOR, 490 .name = "watchdog", 491 .fops = &pc87413_fops, 492 }; 493 494 /* -- Module init functions -------------------------------------*/ 495 496 /** 497 * pc87413_init: module's "constructor" 498 * 499 * Set up the WDT watchdog board. All we have to do is grab the 500 * resources we require and bitch if anyone beat us to them. 501 * The open() function will actually kick the board off. 502 */ 503 504 static int __init pc87413_init(void) 505 { 506 int ret; 507 508 pr_info("Version " VERSION " at io 0x%X\n", 509 WDT_INDEX_IO_PORT); 510 511 if (!request_muxed_region(io, 2, MODNAME)) 512 return -EBUSY; 513 514 ret = register_reboot_notifier(&pc87413_notifier); 515 if (ret != 0) 516 pr_err("cannot register reboot notifier (err=%d)\n", ret); 517 518 ret = misc_register(&pc87413_miscdev); 519 if (ret != 0) { 520 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 521 WATCHDOG_MINOR, ret); 522 goto reboot_unreg; 523 } 524 pr_info("initialized. timeout=%d min\n", timeout); 525 526 pc87413_select_wdt_out(); 527 pc87413_enable_swc(); 528 pc87413_get_swc_base_addr(); 529 530 if (!request_region(swc_base_addr, 0x20, MODNAME)) { 531 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr); 532 ret = -EBUSY; 533 goto misc_unreg; 534 } 535 536 pc87413_enable(); 537 538 release_region(io, 2); 539 return 0; 540 541 misc_unreg: 542 misc_deregister(&pc87413_miscdev); 543 reboot_unreg: 544 unregister_reboot_notifier(&pc87413_notifier); 545 release_region(io, 2); 546 return ret; 547 } 548 549 /** 550 * pc87413_exit: module's "destructor" 551 * 552 * Unload the watchdog. You cannot do this with any file handles open. 553 * If your watchdog is set to continue ticking on close and you unload 554 * it, well it keeps ticking. We won't get the interrupt but the board 555 * will not touch PC memory so all is fine. You just have to load a new 556 * module in 60 seconds or reboot. 557 */ 558 559 static void __exit pc87413_exit(void) 560 { 561 /* Stop the timer before we leave */ 562 if (!nowayout) { 563 pc87413_disable(); 564 pr_info("Watchdog disabled\n"); 565 } 566 567 misc_deregister(&pc87413_miscdev); 568 unregister_reboot_notifier(&pc87413_notifier); 569 release_region(swc_base_addr, 0x20); 570 571 pr_info("watchdog component driver removed\n"); 572 } 573 574 module_init(pc87413_init); 575 module_exit(pc87413_exit); 576 577 MODULE_AUTHOR("Sven Anders <anders@anduras.de>"); 578 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>"); 579 MODULE_DESCRIPTION("PC87413 WDT driver"); 580 MODULE_LICENSE("GPL"); 581 582 module_param_hw(io, int, ioport, 0); 583 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " 584 __MODULE_STRING(IO_DEFAULT) ")."); 585 586 module_param(timeout, int, 0); 587 MODULE_PARM_DESC(timeout, 588 "Watchdog timeout in minutes (default=" 589 __MODULE_STRING(DEFAULT_TIMEOUT) ")."); 590 591 module_param(nowayout, bool, 0); 592 MODULE_PARM_DESC(nowayout, 593 "Watchdog cannot be stopped once started (default=" 594 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 595 596