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/io.h> 34 #include <linux/uaccess.h> 35 36 #include <asm/system.h> 37 38 /* #define DEBUG 1 */ 39 40 #define DEFAULT_TIMEOUT 1 /* 1 minute */ 41 #define MAX_TIMEOUT 255 42 43 #define VERSION "1.1" 44 #define MODNAME "pc87413 WDT" 45 #define PFX MODNAME ": " 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-Controll-Register */ 53 #define WDTO 0x11 /* Watchdog timeout register */ 54 #define WDCFG 0x12 /* Watchdog config register */ 55 56 static int io = 0x2E; /* Address used on Portwell Boards */ 57 58 static int timeout = DEFAULT_TIMEOUT; /* timeout value */ 59 static unsigned long timer_enabled; /* is the timer enabled? */ 60 61 static char expect_close; /* is the close expected? */ 62 63 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */ 64 65 static int nowayout = WATCHDOG_NOWAYOUT; 66 67 /* -- Low level function ----------------------------------------*/ 68 69 /* Select pins for Watchdog output */ 70 71 static inline void pc87413_select_wdt_out(void) 72 { 73 unsigned int cr_data = 0; 74 75 /* Step 1: Select multiple pin,pin55,as WDT output */ 76 77 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 78 79 cr_data = inb(WDT_DATA_IO_PORT); 80 81 cr_data |= 0x80; /* Set Bit7 to 1*/ 82 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 83 84 outb_p(cr_data, WDT_DATA_IO_PORT); 85 86 #ifdef DEBUG 87 printk(KERN_INFO DPFX 88 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n", 89 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 #ifdef DEBUG 133 printk(KERN_INFO DPFX 134 "Read SWC I/O Base Address: low %d, high %d, res %d\n", 135 addr_l, addr_h, swc_base_addr); 136 #endif 137 return swc_base_addr; 138 } 139 140 /* Select Bank 3 of SWC */ 141 142 static inline void pc87413_swc_bank3(unsigned int swc_base_addr) 143 { 144 /* Step 4: Select Bank3 of SWC */ 145 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f); 146 #ifdef DEBUG 147 printk(KERN_INFO DPFX "Select Bank3 of SWC\n"); 148 #endif 149 } 150 151 /* Set watchdog timeout to x minutes */ 152 153 static inline void pc87413_programm_wdto(unsigned int swc_base_addr, 154 char pc87413_time) 155 { 156 /* Step 5: Programm WDTO, Twd. */ 157 outb_p(pc87413_time, swc_base_addr + WDTO); 158 #ifdef DEBUG 159 printk(KERN_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(unsigned int swc_base_addr) 166 { 167 /* Step 6: Enable WDEN */ 168 outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL); 169 #ifdef DEBUG 170 printk(KERN_INFO DPFX "Enable WDEN\n"); 171 #endif 172 } 173 174 /* Enable SW_WD_TREN */ 175 static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr) 176 { 177 /* Enable SW_WD_TREN */ 178 outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG); 179 #ifdef DEBUG 180 printk(KERN_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(unsigned int swc_base_addr) 187 { 188 /* Disable SW_WD_TREN */ 189 outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG); 190 #ifdef DEBUG 191 printk(KERN_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(unsigned int swc_base_addr) 198 { 199 /* Enable SW_WD_TRG */ 200 outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL); 201 #ifdef DEBUG 202 printk(KERN_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(unsigned int swc_base_addr) 209 { 210 /* Disable SW_WD_TRG */ 211 outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL); 212 #ifdef DEBUG 213 printk(KERN_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 unsigned int swc_base_addr; 224 225 spin_lock(&io_lock); 226 227 pc87413_select_wdt_out(); 228 pc87413_enable_swc(); 229 swc_base_addr = pc87413_get_swc_base(); 230 pc87413_swc_bank3(swc_base_addr); 231 pc87413_programm_wdto(swc_base_addr, timeout); 232 pc87413_enable_wden(swc_base_addr); 233 pc87413_enable_sw_wd_tren(swc_base_addr); 234 pc87413_enable_sw_wd_trg(swc_base_addr); 235 236 spin_unlock(&io_lock); 237 } 238 239 /* Disable the watchdog */ 240 241 static void pc87413_disable(void) 242 { 243 unsigned int swc_base_addr; 244 245 spin_lock(&io_lock); 246 247 pc87413_select_wdt_out(); 248 pc87413_enable_swc(); 249 swc_base_addr = pc87413_get_swc_base(); 250 pc87413_swc_bank3(swc_base_addr); 251 pc87413_disable_sw_wd_tren(swc_base_addr); 252 pc87413_disable_sw_wd_trg(swc_base_addr); 253 pc87413_programm_wdto(swc_base_addr, 0); 254 255 spin_unlock(&io_lock); 256 } 257 258 /* Refresh the watchdog */ 259 260 static void pc87413_refresh(void) 261 { 262 unsigned int swc_base_addr; 263 264 spin_lock(&io_lock); 265 266 pc87413_select_wdt_out(); 267 pc87413_enable_swc(); 268 swc_base_addr = pc87413_get_swc_base(); 269 pc87413_swc_bank3(swc_base_addr); 270 pc87413_disable_sw_wd_tren(swc_base_addr); 271 pc87413_disable_sw_wd_trg(swc_base_addr); 272 pc87413_programm_wdto(swc_base_addr, timeout); 273 pc87413_enable_wden(swc_base_addr); 274 pc87413_enable_sw_wd_tren(swc_base_addr); 275 pc87413_enable_sw_wd_trg(swc_base_addr); 276 277 spin_unlock(&io_lock); 278 } 279 280 /* -- File operations -------------------------------------------*/ 281 282 /** 283 * pc87413_open: 284 * @inode: inode of device 285 * @file: file handle to device 286 * 287 */ 288 289 static int pc87413_open(struct inode *inode, struct file *file) 290 { 291 /* /dev/watchdog can only be opened once */ 292 293 if (test_and_set_bit(0, &timer_enabled)) 294 return -EBUSY; 295 296 if (nowayout) 297 __module_get(THIS_MODULE); 298 299 /* Reload and activate timer */ 300 pc87413_refresh(); 301 302 printk(KERN_INFO MODNAME 303 "Watchdog enabled. Timeout set to %d minute(s).\n", timeout); 304 305 return nonseekable_open(inode, file); 306 } 307 308 /** 309 * pc87413_release: 310 * @inode: inode to board 311 * @file: file handle to board 312 * 313 * The watchdog has a configurable API. There is a religious dispute 314 * between people who want their watchdog to be able to shut down and 315 * those who want to be sure if the watchdog manager dies the machine 316 * reboots. In the former case we disable the counters, in the latter 317 * case you have to open it again very soon. 318 */ 319 320 static int pc87413_release(struct inode *inode, struct file *file) 321 { 322 /* Shut off the timer. */ 323 324 if (expect_close == 42) { 325 pc87413_disable(); 326 printk(KERN_INFO MODNAME 327 "Watchdog disabled, sleeping again...\n"); 328 } else { 329 printk(KERN_CRIT MODNAME 330 "Unexpected close, not stopping watchdog!\n"); 331 pc87413_refresh(); 332 } 333 clear_bit(0, &timer_enabled); 334 expect_close = 0; 335 return 0; 336 } 337 338 /** 339 * pc87413_status: 340 * 341 * return, if the watchdog is enabled (timeout is set...) 342 */ 343 344 345 static int pc87413_status(void) 346 { 347 return 0; /* currently not supported */ 348 } 349 350 /** 351 * pc87413_write: 352 * @file: file handle to the watchdog 353 * @data: data buffer to write 354 * @len: length in bytes 355 * @ppos: pointer to the position to write. No seeks allowed 356 * 357 * A write to a watchdog device is defined as a keepalive signal. Any 358 * write of data will do, as we we don't define content meaning. 359 */ 360 361 static ssize_t pc87413_write(struct file *file, const char __user *data, 362 size_t len, loff_t *ppos) 363 { 364 /* See if we got the magic character 'V' and reload the timer */ 365 if (len) { 366 if (!nowayout) { 367 size_t i; 368 369 /* reset expect flag */ 370 expect_close = 0; 371 372 /* scan to see whether or not we got the 373 magic character */ 374 for (i = 0; i != len; i++) { 375 char c; 376 if (get_user(c, data + i)) 377 return -EFAULT; 378 if (c == 'V') 379 expect_close = 42; 380 } 381 } 382 383 /* someone wrote to us, we should reload the timer */ 384 pc87413_refresh(); 385 } 386 return len; 387 } 388 389 /** 390 * pc87413_ioctl: 391 * @file: file handle to the device 392 * @cmd: watchdog command 393 * @arg: argument pointer 394 * 395 * The watchdog API defines a common set of functions for all watchdogs 396 * according to their available features. We only actually usefully support 397 * querying capabilities and current status. 398 */ 399 400 static long pc87413_ioctl(struct file *file, unsigned int cmd, 401 unsigned long arg) 402 { 403 int new_timeout; 404 405 union { 406 struct watchdog_info __user *ident; 407 int __user *i; 408 } uarg; 409 410 static struct watchdog_info ident = { 411 .options = WDIOF_KEEPALIVEPING | 412 WDIOF_SETTIMEOUT | 413 WDIOF_MAGICCLOSE, 414 .firmware_version = 1, 415 .identity = "PC87413(HF/F) watchdog", 416 }; 417 418 uarg.i = (int __user *)arg; 419 420 switch (cmd) { 421 case WDIOC_GETSUPPORT: 422 return copy_to_user(uarg.ident, &ident, 423 sizeof(ident)) ? -EFAULT : 0; 424 case WDIOC_GETSTATUS: 425 return put_user(pc87413_status(), uarg.i); 426 case WDIOC_GETBOOTSTATUS: 427 return put_user(0, uarg.i); 428 case WDIOC_SETOPTIONS: 429 { 430 int options, retval = -EINVAL; 431 if (get_user(options, uarg.i)) 432 return -EFAULT; 433 if (options & WDIOS_DISABLECARD) { 434 pc87413_disable(); 435 retval = 0; 436 } 437 if (options & WDIOS_ENABLECARD) { 438 pc87413_enable(); 439 retval = 0; 440 } 441 return retval; 442 } 443 case WDIOC_KEEPALIVE: 444 pc87413_refresh(); 445 #ifdef DEBUG 446 printk(KERN_INFO DPFX "keepalive\n"); 447 #endif 448 return 0; 449 case WDIOC_SETTIMEOUT: 450 if (get_user(new_timeout, uarg.i)) 451 return -EFAULT; 452 /* the API states this is given in secs */ 453 new_timeout /= 60; 454 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 455 return -EINVAL; 456 timeout = new_timeout; 457 pc87413_refresh(); 458 /* fall through and return the new timeout... */ 459 case WDIOC_GETTIMEOUT: 460 new_timeout = timeout * 60; 461 return put_user(new_timeout, uarg.i); 462 default: 463 return -ENOTTY; 464 } 465 } 466 467 /* -- Notifier funtions -----------------------------------------*/ 468 469 /** 470 * notify_sys: 471 * @this: our notifier block 472 * @code: the event being reported 473 * @unused: unused 474 * 475 * Our notifier is called on system shutdowns. We want to turn the card 476 * off at reboot otherwise the machine will reboot again during memory 477 * test or worse yet during the following fsck. This would suck, in fact 478 * trust me - if it happens it does suck. 479 */ 480 481 static int pc87413_notify_sys(struct notifier_block *this, 482 unsigned long code, 483 void *unused) 484 { 485 if (code == SYS_DOWN || code == SYS_HALT) 486 /* Turn the card off */ 487 pc87413_disable(); 488 return NOTIFY_DONE; 489 } 490 491 /* -- Module's structures ---------------------------------------*/ 492 493 static const struct file_operations pc87413_fops = { 494 .owner = THIS_MODULE, 495 .llseek = no_llseek, 496 .write = pc87413_write, 497 .unlocked_ioctl = pc87413_ioctl, 498 .open = pc87413_open, 499 .release = pc87413_release, 500 }; 501 502 static struct notifier_block pc87413_notifier = { 503 .notifier_call = pc87413_notify_sys, 504 }; 505 506 static struct miscdevice pc87413_miscdev = { 507 .minor = WATCHDOG_MINOR, 508 .name = "watchdog", 509 .fops = &pc87413_fops, 510 }; 511 512 /* -- Module init functions -------------------------------------*/ 513 514 /** 515 * pc87413_init: module's "constructor" 516 * 517 * Set up the WDT watchdog board. All we have to do is grab the 518 * resources we require and bitch if anyone beat us to them. 519 * The open() function will actually kick the board off. 520 */ 521 522 static int __init pc87413_init(void) 523 { 524 int ret; 525 526 printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n", 527 WDT_INDEX_IO_PORT); 528 529 /* request_region(io, 2, "pc87413"); */ 530 531 ret = register_reboot_notifier(&pc87413_notifier); 532 if (ret != 0) { 533 printk(KERN_ERR PFX 534 "cannot register reboot notifier (err=%d)\n", ret); 535 } 536 537 ret = misc_register(&pc87413_miscdev); 538 if (ret != 0) { 539 printk(KERN_ERR PFX 540 "cannot register miscdev on minor=%d (err=%d)\n", 541 WATCHDOG_MINOR, ret); 542 unregister_reboot_notifier(&pc87413_notifier); 543 return ret; 544 } 545 printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout); 546 pc87413_enable(); 547 return 0; 548 } 549 550 /** 551 * pc87413_exit: module's "destructor" 552 * 553 * Unload the watchdog. You cannot do this with any file handles open. 554 * If your watchdog is set to continue ticking on close and you unload 555 * it, well it keeps ticking. We won't get the interrupt but the board 556 * will not touch PC memory so all is fine. You just have to load a new 557 * module in 60 seconds or reboot. 558 */ 559 560 static void __exit pc87413_exit(void) 561 { 562 /* Stop the timer before we leave */ 563 if (!nowayout) { 564 pc87413_disable(); 565 printk(KERN_INFO MODNAME "Watchdog disabled.\n"); 566 } 567 568 misc_deregister(&pc87413_miscdev); 569 unregister_reboot_notifier(&pc87413_notifier); 570 /* release_region(io, 2); */ 571 572 printk(KERN_INFO MODNAME " watchdog component driver removed.\n"); 573 } 574 575 module_init(pc87413_init); 576 module_exit(pc87413_exit); 577 578 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, " 579 "Marcus Junker <junker@anduras.de>,"); 580 MODULE_DESCRIPTION("PC87413 WDT driver"); 581 MODULE_LICENSE("GPL"); 582 583 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 584 585 module_param(io, int, 0); 586 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ")."); 587 588 module_param(timeout, int, 0); 589 MODULE_PARM_DESC(timeout, 590 "Watchdog timeout in minutes (default=" 591 __MODULE_STRING(timeout) ")."); 592 593 module_param(nowayout, int, 0); 594 MODULE_PARM_DESC(nowayout, 595 "Watchdog cannot be stopped once started (default=" 596 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 597 598