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 #include <linux/module.h> 22 #include <linux/types.h> 23 #include <linux/miscdevice.h> 24 #include <linux/watchdog.h> 25 #include <linux/ioport.h> 26 #include <linux/delay.h> 27 #include <linux/notifier.h> 28 #include <linux/fs.h> 29 #include <linux/reboot.h> 30 #include <linux/init.h> 31 #include <linux/spinlock.h> 32 #include <linux/moduleparam.h> 33 #include <linux/version.h> 34 35 #include <asm/io.h> 36 #include <asm/uaccess.h> 37 #include <asm/system.h> 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 PFX MODNAME ": " 47 #define DPFX MODNAME " - DEBUG: " 48 49 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */ 50 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1) 51 #define SWC_LDN 0x04 52 #define SIOCFG2 0x22 /* Serial IO register */ 53 #define WDCTL 0x10 /* Watchdog-Timer-Controll-Register */ 54 #define WDTO 0x11 /* Watchdog timeout register */ 55 #define WDCFG 0x12 /* Watchdog config register */ 56 57 static int io = 0x2E; /* Address used on Portwell Boards */ 58 59 static int timeout = DEFAULT_TIMEOUT; /* timeout value */ 60 static unsigned long timer_enabled = 0; /* is the timer enabled? */ 61 62 static char expect_close; /* is the close expected? */ 63 64 static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */ 65 66 static int nowayout = WATCHDOG_NOWAYOUT; 67 68 /* -- Low level function ----------------------------------------*/ 69 70 /* Select pins for Watchdog output */ 71 72 static inline void pc87413_select_wdt_out (void) 73 { 74 unsigned int cr_data = 0; 75 76 /* Step 1: Select multiple pin,pin55,as WDT output */ 77 78 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 79 80 cr_data = inb (WDT_DATA_IO_PORT); 81 82 cr_data |= 0x80; /* Set Bit7 to 1*/ 83 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 84 85 outb_p(cr_data, WDT_DATA_IO_PORT); 86 87 #ifdef DEBUG 88 printk(KERN_INFO DPFX "Select multiple pin,pin55,as WDT output:" 89 " Bit7 to 1: %d\n", cr_data); 90 #endif 91 } 92 93 /* Enable SWC functions */ 94 95 static inline void pc87413_enable_swc(void) 96 { 97 unsigned int cr_data=0; 98 99 /* Step 2: Enable SWC functions */ 100 101 outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */ 102 outb_p(SWC_LDN, WDT_DATA_IO_PORT); 103 104 outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */ 105 cr_data = inb(WDT_DATA_IO_PORT); 106 cr_data |= 0x01; /* Set Bit0 to 1 */ 107 outb_p(0x30, WDT_INDEX_IO_PORT); 108 outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */ 109 110 #ifdef DEBUG 111 printk(KERN_INFO DPFX "pc87413 - Enable SWC functions\n"); 112 #endif 113 } 114 115 /* Read SWC I/O base address */ 116 117 static inline unsigned int pc87413_get_swc_base(void) 118 { 119 unsigned int swc_base_addr = 0; 120 unsigned char addr_l, addr_h = 0; 121 122 /* Step 3: Read SWC I/O Base Address */ 123 124 outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */ 125 addr_h = inb(WDT_DATA_IO_PORT); 126 127 outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */ 128 129 addr_l = inb(WDT_DATA_IO_PORT); 130 131 swc_base_addr = (addr_h << 8) + addr_l; 132 133 #ifdef DEBUG 134 printk(KERN_INFO DPFX "Read SWC I/O Base Address: low %d, high %d," 135 " res %d\n", addr_l, addr_h, swc_base_addr); 136 #endif 137 138 return swc_base_addr; 139 } 140 141 /* Select Bank 3 of SWC */ 142 143 static inline void pc87413_swc_bank3(unsigned int swc_base_addr) 144 { 145 /* Step 4: Select Bank3 of SWC */ 146 147 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f); 148 149 #ifdef DEBUG 150 printk(KERN_INFO DPFX "Select Bank3 of SWC\n"); 151 #endif 152 } 153 154 /* Set watchdog timeout to x minutes */ 155 156 static inline void pc87413_programm_wdto(unsigned int swc_base_addr, 157 char pc87413_time) 158 { 159 /* Step 5: Programm WDTO, Twd. */ 160 161 outb_p(pc87413_time, swc_base_addr + WDTO); 162 163 #ifdef DEBUG 164 printk(KERN_INFO DPFX "Set WDTO to %d minutes\n", pc87413_time); 165 #endif 166 } 167 168 /* Enable WDEN */ 169 170 static inline void pc87413_enable_wden(unsigned int swc_base_addr) 171 { 172 /* Step 6: Enable WDEN */ 173 174 outb_p(inb (swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL); 175 176 #ifdef DEBUG 177 printk(KERN_INFO DPFX "Enable WDEN\n"); 178 #endif 179 } 180 181 /* Enable SW_WD_TREN */ 182 static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr) 183 { 184 /* Enable SW_WD_TREN */ 185 186 outb_p(inb (swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG); 187 188 #ifdef DEBUG 189 printk(KERN_INFO DPFX "Enable SW_WD_TREN\n"); 190 #endif 191 } 192 193 /* Disable SW_WD_TREN */ 194 195 static inline void pc87413_disable_sw_wd_tren(unsigned int swc_base_addr) 196 { 197 /* Disable SW_WD_TREN */ 198 199 outb_p(inb (swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG); 200 201 #ifdef DEBUG 202 printk(KERN_INFO DPFX "pc87413 - Disable SW_WD_TREN\n"); 203 #endif 204 } 205 206 /* Enable SW_WD_TRG */ 207 208 static inline void pc87413_enable_sw_wd_trg(unsigned int swc_base_addr) 209 { 210 /* Enable SW_WD_TRG */ 211 212 outb_p(inb (swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL); 213 214 #ifdef DEBUG 215 printk(KERN_INFO DPFX "pc87413 - Enable SW_WD_TRG\n"); 216 #endif 217 } 218 219 /* Disable SW_WD_TRG */ 220 221 static inline void pc87413_disable_sw_wd_trg(unsigned int swc_base_addr) 222 { 223 /* Disable SW_WD_TRG */ 224 225 outb_p(inb (swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL); 226 227 #ifdef DEBUG 228 printk(KERN_INFO DPFX "Disable SW_WD_TRG\n"); 229 #endif 230 } 231 232 /* -- Higher level functions ------------------------------------*/ 233 234 /* Enable the watchdog */ 235 236 static void pc87413_enable(void) 237 { 238 unsigned int swc_base_addr; 239 240 spin_lock(&io_lock); 241 242 pc87413_select_wdt_out(); 243 pc87413_enable_swc(); 244 swc_base_addr = pc87413_get_swc_base(); 245 pc87413_swc_bank3(swc_base_addr); 246 pc87413_programm_wdto(swc_base_addr, timeout); 247 pc87413_enable_wden(swc_base_addr); 248 pc87413_enable_sw_wd_tren(swc_base_addr); 249 pc87413_enable_sw_wd_trg(swc_base_addr); 250 251 spin_unlock(&io_lock); 252 } 253 254 /* Disable the watchdog */ 255 256 static void pc87413_disable(void) 257 { 258 unsigned int swc_base_addr; 259 260 spin_lock(&io_lock); 261 262 pc87413_select_wdt_out(); 263 pc87413_enable_swc(); 264 swc_base_addr = pc87413_get_swc_base(); 265 pc87413_swc_bank3(swc_base_addr); 266 pc87413_disable_sw_wd_tren(swc_base_addr); 267 pc87413_disable_sw_wd_trg(swc_base_addr); 268 pc87413_programm_wdto(swc_base_addr, 0); 269 270 spin_unlock(&io_lock); 271 } 272 273 /* Refresh the watchdog */ 274 275 static void pc87413_refresh(void) 276 { 277 unsigned int swc_base_addr; 278 279 spin_lock(&io_lock); 280 281 pc87413_select_wdt_out(); 282 pc87413_enable_swc(); 283 swc_base_addr = pc87413_get_swc_base(); 284 pc87413_swc_bank3(swc_base_addr); 285 pc87413_disable_sw_wd_tren(swc_base_addr); 286 pc87413_disable_sw_wd_trg(swc_base_addr); 287 pc87413_programm_wdto(swc_base_addr, timeout); 288 pc87413_enable_wden(swc_base_addr); 289 pc87413_enable_sw_wd_tren(swc_base_addr); 290 pc87413_enable_sw_wd_trg(swc_base_addr); 291 292 spin_unlock(&io_lock); 293 } 294 295 /* -- File operations -------------------------------------------*/ 296 297 /** 298 * pc87413_open: 299 * @inode: inode of device 300 * @file: file handle to device 301 * 302 */ 303 304 static int pc87413_open(struct inode *inode, struct file *file) 305 { 306 /* /dev/watchdog can only be opened once */ 307 308 if (test_and_set_bit(0, &timer_enabled)) 309 return -EBUSY; 310 311 if (nowayout) 312 __module_get(THIS_MODULE); 313 314 /* Reload and activate timer */ 315 pc87413_refresh(); 316 317 printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to" 318 " %d minute(s).\n", timeout); 319 320 return nonseekable_open(inode, file); 321 } 322 323 /** 324 * pc87413_release: 325 * @inode: inode to board 326 * @file: file handle to board 327 * 328 * The watchdog has a configurable API. There is a religious dispute 329 * between people who want their watchdog to be able to shut down and 330 * those who want to be sure if the watchdog manager dies the machine 331 * reboots. In the former case we disable the counters, in the latter 332 * case you have to open it again very soon. 333 */ 334 335 static int pc87413_release(struct inode *inode, struct file *file) 336 { 337 /* Shut off the timer. */ 338 339 if (expect_close == 42) { 340 pc87413_disable(); 341 printk(KERN_INFO MODNAME "Watchdog disabled," 342 " sleeping again...\n"); 343 } else { 344 printk(KERN_CRIT MODNAME "Unexpected close, not stopping" 345 " watchdog!\n"); 346 pc87413_refresh(); 347 } 348 349 clear_bit(0, &timer_enabled); 350 expect_close = 0; 351 352 return 0; 353 } 354 355 /** 356 * pc87413_status: 357 * 358 * return, if the watchdog is enabled (timeout is set...) 359 */ 360 361 362 static int pc87413_status(void) 363 { 364 return 0; /* currently not supported */ 365 } 366 367 /** 368 * pc87413_write: 369 * @file: file handle to the watchdog 370 * @data: data buffer to write 371 * @len: length in bytes 372 * @ppos: pointer to the position to write. No seeks allowed 373 * 374 * A write to a watchdog device is defined as a keepalive signal. Any 375 * write of data will do, as we we don't define content meaning. 376 */ 377 378 static ssize_t pc87413_write(struct file *file, const char __user *data, 379 size_t len, loff_t *ppos) 380 { 381 /* See if we got the magic character 'V' and reload the timer */ 382 if (len) { 383 if (!nowayout) { 384 size_t i; 385 386 /* reset expect flag */ 387 expect_close = 0; 388 389 /* scan to see whether or not we got the magic character */ 390 for (i = 0; i != len; i++) { 391 char c; 392 if (get_user(c, data+i)) 393 return -EFAULT; 394 if (c == 'V') 395 expect_close = 42; 396 } 397 } 398 399 /* someone wrote to us, we should reload the timer */ 400 pc87413_refresh(); 401 } 402 return len; 403 } 404 405 /** 406 * pc87413_ioctl: 407 * @inode: inode of the device 408 * @file: file handle to the device 409 * @cmd: watchdog command 410 * @arg: argument pointer 411 * 412 * The watchdog API defines a common set of functions for all watchdogs 413 * according to their available features. We only actually usefully support 414 * querying capabilities and current status. 415 */ 416 417 static int pc87413_ioctl(struct inode *inode, struct file *file, 418 unsigned int cmd, unsigned long arg) 419 { 420 int new_timeout; 421 422 union { 423 struct watchdog_info __user *ident; 424 int __user *i; 425 } uarg; 426 427 static struct watchdog_info ident = { 428 .options = WDIOF_KEEPALIVEPING | 429 WDIOF_SETTIMEOUT | 430 WDIOF_MAGICCLOSE, 431 .firmware_version = 1, 432 .identity = "PC87413(HF/F) watchdog" 433 }; 434 435 uarg.i = (int __user *)arg; 436 437 switch(cmd) { 438 default: 439 return -ENOTTY; 440 441 case WDIOC_GETSUPPORT: 442 return copy_to_user(uarg.ident, &ident, 443 sizeof(ident)) ? -EFAULT : 0; 444 445 case WDIOC_GETSTATUS: 446 return put_user(pc87413_status(), uarg.i); 447 448 case WDIOC_GETBOOTSTATUS: 449 return put_user(0, uarg.i); 450 451 case WDIOC_KEEPALIVE: 452 pc87413_refresh(); 453 #ifdef DEBUG 454 printk(KERN_INFO DPFX "keepalive\n"); 455 #endif 456 return 0; 457 458 case WDIOC_SETTIMEOUT: 459 if (get_user(new_timeout, uarg.i)) 460 return -EFAULT; 461 462 // the API states this is given in secs 463 new_timeout /= 60; 464 465 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 466 return -EINVAL; 467 468 timeout = new_timeout; 469 pc87413_refresh(); 470 471 // fall through and return the new timeout... 472 473 case WDIOC_GETTIMEOUT: 474 475 new_timeout = timeout * 60; 476 477 return put_user(new_timeout, uarg.i); 478 479 case WDIOC_SETOPTIONS: 480 { 481 int options, retval = -EINVAL; 482 483 if (get_user(options, uarg.i)) 484 return -EFAULT; 485 486 if (options & WDIOS_DISABLECARD) { 487 pc87413_disable(); 488 retval = 0; 489 } 490 491 if (options & WDIOS_ENABLECARD) { 492 pc87413_enable(); 493 retval = 0; 494 } 495 496 return retval; 497 } 498 } 499 } 500 501 /* -- Notifier funtions -----------------------------------------*/ 502 503 /** 504 * notify_sys: 505 * @this: our notifier block 506 * @code: the event being reported 507 * @unused: unused 508 * 509 * Our notifier is called on system shutdowns. We want to turn the card 510 * off at reboot otherwise the machine will reboot again during memory 511 * test or worse yet during the following fsck. This would suck, in fact 512 * trust me - if it happens it does suck. 513 */ 514 515 static int pc87413_notify_sys(struct notifier_block *this, 516 unsigned long code, 517 void *unused) 518 { 519 if (code == SYS_DOWN || code == SYS_HALT) 520 { 521 /* Turn the card off */ 522 pc87413_disable(); 523 } 524 return NOTIFY_DONE; 525 } 526 527 /* -- Module's structures ---------------------------------------*/ 528 529 static const struct file_operations pc87413_fops = { 530 .owner = THIS_MODULE, 531 .llseek = no_llseek, 532 .write = pc87413_write, 533 .ioctl = pc87413_ioctl, 534 .open = pc87413_open, 535 .release = pc87413_release, 536 }; 537 538 static struct notifier_block pc87413_notifier = 539 { 540 .notifier_call = pc87413_notify_sys, 541 }; 542 543 static struct miscdevice pc87413_miscdev= 544 { 545 .minor = WATCHDOG_MINOR, 546 .name = "watchdog", 547 .fops = &pc87413_fops 548 }; 549 550 /* -- Module init functions -------------------------------------*/ 551 552 /** 553 * pc87413_init: module's "constructor" 554 * 555 * Set up the WDT watchdog board. All we have to do is grab the 556 * resources we require and bitch if anyone beat us to them. 557 * The open() function will actually kick the board off. 558 */ 559 560 static int __init pc87413_init(void) 561 { 562 int ret; 563 564 printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n", WDT_INDEX_IO_PORT); 565 566 /* request_region(io, 2, "pc87413"); */ 567 568 ret = register_reboot_notifier(&pc87413_notifier); 569 if (ret != 0) { 570 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", 571 ret); 572 } 573 574 ret = misc_register(&pc87413_miscdev); 575 576 if (ret != 0) { 577 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", 578 WATCHDOG_MINOR, ret); 579 unregister_reboot_notifier(&pc87413_notifier); 580 return ret; 581 } 582 583 printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout); 584 585 pc87413_enable(); 586 587 return 0; 588 } 589 590 /** 591 * pc87413_exit: module's "destructor" 592 * 593 * Unload the watchdog. You cannot do this with any file handles open. 594 * If your watchdog is set to continue ticking on close and you unload 595 * it, well it keeps ticking. We won't get the interrupt but the board 596 * will not touch PC memory so all is fine. You just have to load a new 597 * module in 60 seconds or reboot. 598 */ 599 600 static void __exit pc87413_exit(void) 601 { 602 /* Stop the timer before we leave */ 603 if (!nowayout) 604 { 605 pc87413_disable(); 606 printk(KERN_INFO MODNAME "Watchdog disabled.\n"); 607 } 608 609 misc_deregister(&pc87413_miscdev); 610 unregister_reboot_notifier(&pc87413_notifier); 611 /* release_region(io,2); */ 612 613 printk(MODNAME " watchdog component driver removed.\n"); 614 } 615 616 module_init(pc87413_init); 617 module_exit(pc87413_exit); 618 619 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, Marcus Junker <junker@anduras.de>,"); 620 MODULE_DESCRIPTION("PC87413 WDT driver"); 621 MODULE_LICENSE("GPL"); 622 623 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 624 625 module_param(io, int, 0); 626 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ")."); 627 628 module_param(timeout, int, 0); 629 MODULE_PARM_DESC(timeout, "Watchdog timeout in minutes (default=" __MODULE_STRING(timeout) ")."); 630 631 module_param(nowayout, int, 0); 632 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 633 634