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