1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x 4 * 5 * This code is based on wdt.c with original copyright. 6 * 7 * (C) Copyright 2006 Sven Anders, <anders@anduras.de> 8 * and Marcus Junker, <junker@anduras.de> 9 * 10 * Neither Sven Anders, Marcus Junker nor ANDURAS AG 11 * admit liability nor provide warranty for any of this software. 12 * This material is provided "AS-IS" and at no charge. 13 * 14 * Release 1.1 15 */ 16 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19 #include <linux/module.h> 20 #include <linux/types.h> 21 #include <linux/miscdevice.h> 22 #include <linux/watchdog.h> 23 #include <linux/ioport.h> 24 #include <linux/delay.h> 25 #include <linux/notifier.h> 26 #include <linux/fs.h> 27 #include <linux/reboot.h> 28 #include <linux/init.h> 29 #include <linux/spinlock.h> 30 #include <linux/moduleparam.h> 31 #include <linux/io.h> 32 #include <linux/uaccess.h> 33 34 35 /* #define DEBUG 1 */ 36 37 #define DEFAULT_TIMEOUT 1 /* 1 minute */ 38 #define MAX_TIMEOUT 255 39 40 #define VERSION "1.1" 41 #define MODNAME "pc87413 WDT" 42 #define DPFX MODNAME " - DEBUG: " 43 44 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */ 45 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1) 46 #define SWC_LDN 0x04 47 #define SIOCFG2 0x22 /* Serial IO register */ 48 #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */ 49 #define WDTO 0x11 /* Watchdog timeout register */ 50 #define WDCFG 0x12 /* Watchdog config register */ 51 52 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */ 53 54 static int io = IO_DEFAULT; 55 static int swc_base_addr = -1; 56 57 static int timeout = DEFAULT_TIMEOUT; /* timeout value */ 58 static unsigned long timer_enabled; /* is the timer enabled? */ 59 60 static char expect_close; /* is the close expected? */ 61 62 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */ 63 64 static bool nowayout = WATCHDOG_NOWAYOUT; 65 66 /* -- Low level function ----------------------------------------*/ 67 68 /* Select pins for Watchdog output */ 69 70 static inline void pc87413_select_wdt_out(void) 71 { 72 unsigned int cr_data = 0; 73 74 /* Step 1: Select multiple pin,pin55,as WDT output */ 75 76 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 77 78 cr_data = inb(WDT_DATA_IO_PORT); 79 80 cr_data |= 0x80; /* Set Bit7 to 1*/ 81 outb_p(SIOCFG2, WDT_INDEX_IO_PORT); 82 83 outb_p(cr_data, WDT_DATA_IO_PORT); 84 85 #ifdef DEBUG 86 pr_info(DPFX 87 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n", 88 cr_data); 89 #endif 90 } 91 92 /* Enable SWC functions */ 93 94 static inline void pc87413_enable_swc(void) 95 { 96 unsigned int cr_data = 0; 97 98 /* Step 2: Enable SWC functions */ 99 100 outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */ 101 outb_p(SWC_LDN, WDT_DATA_IO_PORT); 102 103 outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */ 104 cr_data = inb(WDT_DATA_IO_PORT); 105 cr_data |= 0x01; /* Set Bit0 to 1 */ 106 outb_p(0x30, WDT_INDEX_IO_PORT); 107 outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */ 108 109 #ifdef DEBUG 110 pr_info(DPFX "pc87413 - Enable SWC functions\n"); 111 #endif 112 } 113 114 /* Read SWC I/O base address */ 115 116 static void pc87413_get_swc_base_addr(void) 117 { 118 unsigned char addr_l, addr_h = 0; 119 120 /* Step 3: Read SWC I/O Base Address */ 121 122 outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */ 123 addr_h = inb(WDT_DATA_IO_PORT); 124 125 outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */ 126 127 addr_l = inb(WDT_DATA_IO_PORT); 128 129 swc_base_addr = (addr_h << 8) + addr_l; 130 #ifdef DEBUG 131 pr_info(DPFX 132 "Read SWC I/O Base Address: low %d, high %d, res %d\n", 133 addr_l, addr_h, swc_base_addr); 134 #endif 135 } 136 137 /* Select Bank 3 of SWC */ 138 139 static inline void pc87413_swc_bank3(void) 140 { 141 /* Step 4: Select Bank3 of SWC */ 142 outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f); 143 #ifdef DEBUG 144 pr_info(DPFX "Select Bank3 of SWC\n"); 145 #endif 146 } 147 148 /* Set watchdog timeout to x minutes */ 149 150 static inline void pc87413_programm_wdto(char pc87413_time) 151 { 152 /* Step 5: Programm WDTO, Twd. */ 153 outb_p(pc87413_time, swc_base_addr + WDTO); 154 #ifdef DEBUG 155 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time); 156 #endif 157 } 158 159 /* Enable WDEN */ 160 161 static inline void pc87413_enable_wden(void) 162 { 163 /* Step 6: Enable WDEN */ 164 outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL); 165 #ifdef DEBUG 166 pr_info(DPFX "Enable WDEN\n"); 167 #endif 168 } 169 170 /* Enable SW_WD_TREN */ 171 static inline void pc87413_enable_sw_wd_tren(void) 172 { 173 /* Enable SW_WD_TREN */ 174 outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG); 175 #ifdef DEBUG 176 pr_info(DPFX "Enable SW_WD_TREN\n"); 177 #endif 178 } 179 180 /* Disable SW_WD_TREN */ 181 182 static inline void pc87413_disable_sw_wd_tren(void) 183 { 184 /* Disable SW_WD_TREN */ 185 outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG); 186 #ifdef DEBUG 187 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n"); 188 #endif 189 } 190 191 /* Enable SW_WD_TRG */ 192 193 static inline void pc87413_enable_sw_wd_trg(void) 194 { 195 /* Enable SW_WD_TRG */ 196 outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL); 197 #ifdef DEBUG 198 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n"); 199 #endif 200 } 201 202 /* Disable SW_WD_TRG */ 203 204 static inline void pc87413_disable_sw_wd_trg(void) 205 { 206 /* Disable SW_WD_TRG */ 207 outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL); 208 #ifdef DEBUG 209 pr_info(DPFX "Disable SW_WD_TRG\n"); 210 #endif 211 } 212 213 /* -- Higher level functions ------------------------------------*/ 214 215 /* Enable the watchdog */ 216 217 static void pc87413_enable(void) 218 { 219 spin_lock(&io_lock); 220 221 pc87413_swc_bank3(); 222 pc87413_programm_wdto(timeout); 223 pc87413_enable_wden(); 224 pc87413_enable_sw_wd_tren(); 225 pc87413_enable_sw_wd_trg(); 226 227 spin_unlock(&io_lock); 228 } 229 230 /* Disable the watchdog */ 231 232 static void pc87413_disable(void) 233 { 234 spin_lock(&io_lock); 235 236 pc87413_swc_bank3(); 237 pc87413_disable_sw_wd_tren(); 238 pc87413_disable_sw_wd_trg(); 239 pc87413_programm_wdto(0); 240 241 spin_unlock(&io_lock); 242 } 243 244 /* Refresh the watchdog */ 245 246 static void pc87413_refresh(void) 247 { 248 spin_lock(&io_lock); 249 250 pc87413_swc_bank3(); 251 pc87413_disable_sw_wd_tren(); 252 pc87413_disable_sw_wd_trg(); 253 pc87413_programm_wdto(timeout); 254 pc87413_enable_wden(); 255 pc87413_enable_sw_wd_tren(); 256 pc87413_enable_sw_wd_trg(); 257 258 spin_unlock(&io_lock); 259 } 260 261 /* -- File operations -------------------------------------------*/ 262 263 /** 264 * pc87413_open: 265 * @inode: inode of device 266 * @file: file handle to device 267 * 268 */ 269 270 static int pc87413_open(struct inode *inode, struct file *file) 271 { 272 /* /dev/watchdog can only be opened once */ 273 274 if (test_and_set_bit(0, &timer_enabled)) 275 return -EBUSY; 276 277 if (nowayout) 278 __module_get(THIS_MODULE); 279 280 /* Reload and activate timer */ 281 pc87413_refresh(); 282 283 pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout); 284 285 return stream_open(inode, file); 286 } 287 288 /** 289 * pc87413_release: 290 * @inode: inode to board 291 * @file: file handle to board 292 * 293 * The watchdog has a configurable API. There is a religious dispute 294 * between people who want their watchdog to be able to shut down and 295 * those who want to be sure if the watchdog manager dies the machine 296 * reboots. In the former case we disable the counters, in the latter 297 * case you have to open it again very soon. 298 */ 299 300 static int pc87413_release(struct inode *inode, struct file *file) 301 { 302 /* Shut off the timer. */ 303 304 if (expect_close == 42) { 305 pc87413_disable(); 306 pr_info("Watchdog disabled, sleeping again...\n"); 307 } else { 308 pr_crit("Unexpected close, not stopping watchdog!\n"); 309 pc87413_refresh(); 310 } 311 clear_bit(0, &timer_enabled); 312 expect_close = 0; 313 return 0; 314 } 315 316 /** 317 * pc87413_status: 318 * 319 * return, if the watchdog is enabled (timeout is set...) 320 */ 321 322 323 static int pc87413_status(void) 324 { 325 return 0; /* currently not supported */ 326 } 327 328 /** 329 * pc87413_write: 330 * @file: file handle to the watchdog 331 * @data: data buffer to write 332 * @len: length in bytes 333 * @ppos: pointer to the position to write. No seeks allowed 334 * 335 * A write to a watchdog device is defined as a keepalive signal. Any 336 * write of data will do, as we we don't define content meaning. 337 */ 338 339 static ssize_t pc87413_write(struct file *file, const char __user *data, 340 size_t len, loff_t *ppos) 341 { 342 /* See if we got the magic character 'V' and reload the timer */ 343 if (len) { 344 if (!nowayout) { 345 size_t i; 346 347 /* reset expect flag */ 348 expect_close = 0; 349 350 /* scan to see whether or not we got the 351 magic character */ 352 for (i = 0; i != len; i++) { 353 char c; 354 if (get_user(c, data + i)) 355 return -EFAULT; 356 if (c == 'V') 357 expect_close = 42; 358 } 359 } 360 361 /* someone wrote to us, we should reload the timer */ 362 pc87413_refresh(); 363 } 364 return len; 365 } 366 367 /** 368 * pc87413_ioctl: 369 * @file: file handle to the device 370 * @cmd: watchdog command 371 * @arg: argument pointer 372 * 373 * The watchdog API defines a common set of functions for all watchdogs 374 * according to their available features. We only actually usefully support 375 * querying capabilities and current status. 376 */ 377 378 static long pc87413_ioctl(struct file *file, unsigned int cmd, 379 unsigned long arg) 380 { 381 int new_timeout; 382 383 union { 384 struct watchdog_info __user *ident; 385 int __user *i; 386 } uarg; 387 388 static const struct watchdog_info ident = { 389 .options = WDIOF_KEEPALIVEPING | 390 WDIOF_SETTIMEOUT | 391 WDIOF_MAGICCLOSE, 392 .firmware_version = 1, 393 .identity = "PC87413(HF/F) watchdog", 394 }; 395 396 uarg.i = (int __user *)arg; 397 398 switch (cmd) { 399 case WDIOC_GETSUPPORT: 400 return copy_to_user(uarg.ident, &ident, 401 sizeof(ident)) ? -EFAULT : 0; 402 case WDIOC_GETSTATUS: 403 return put_user(pc87413_status(), uarg.i); 404 case WDIOC_GETBOOTSTATUS: 405 return put_user(0, uarg.i); 406 case WDIOC_SETOPTIONS: 407 { 408 int options, retval = -EINVAL; 409 if (get_user(options, uarg.i)) 410 return -EFAULT; 411 if (options & WDIOS_DISABLECARD) { 412 pc87413_disable(); 413 retval = 0; 414 } 415 if (options & WDIOS_ENABLECARD) { 416 pc87413_enable(); 417 retval = 0; 418 } 419 return retval; 420 } 421 case WDIOC_KEEPALIVE: 422 pc87413_refresh(); 423 #ifdef DEBUG 424 pr_info(DPFX "keepalive\n"); 425 #endif 426 return 0; 427 case WDIOC_SETTIMEOUT: 428 if (get_user(new_timeout, uarg.i)) 429 return -EFAULT; 430 /* the API states this is given in secs */ 431 new_timeout /= 60; 432 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 433 return -EINVAL; 434 timeout = new_timeout; 435 pc87413_refresh(); 436 /* fall through - and return the new timeout... */ 437 case WDIOC_GETTIMEOUT: 438 new_timeout = timeout * 60; 439 return put_user(new_timeout, uarg.i); 440 default: 441 return -ENOTTY; 442 } 443 } 444 445 /* -- Notifier funtions -----------------------------------------*/ 446 447 /** 448 * notify_sys: 449 * @this: our notifier block 450 * @code: the event being reported 451 * @unused: unused 452 * 453 * Our notifier is called on system shutdowns. We want to turn the card 454 * off at reboot otherwise the machine will reboot again during memory 455 * test or worse yet during the following fsck. This would suck, in fact 456 * trust me - if it happens it does suck. 457 */ 458 459 static int pc87413_notify_sys(struct notifier_block *this, 460 unsigned long code, 461 void *unused) 462 { 463 if (code == SYS_DOWN || code == SYS_HALT) 464 /* Turn the card off */ 465 pc87413_disable(); 466 return NOTIFY_DONE; 467 } 468 469 /* -- Module's structures ---------------------------------------*/ 470 471 static const struct file_operations pc87413_fops = { 472 .owner = THIS_MODULE, 473 .llseek = no_llseek, 474 .write = pc87413_write, 475 .unlocked_ioctl = pc87413_ioctl, 476 .open = pc87413_open, 477 .release = pc87413_release, 478 }; 479 480 static struct notifier_block pc87413_notifier = { 481 .notifier_call = pc87413_notify_sys, 482 }; 483 484 static struct miscdevice pc87413_miscdev = { 485 .minor = WATCHDOG_MINOR, 486 .name = "watchdog", 487 .fops = &pc87413_fops, 488 }; 489 490 /* -- Module init functions -------------------------------------*/ 491 492 /** 493 * pc87413_init: module's "constructor" 494 * 495 * Set up the WDT watchdog board. All we have to do is grab the 496 * resources we require and bitch if anyone beat us to them. 497 * The open() function will actually kick the board off. 498 */ 499 500 static int __init pc87413_init(void) 501 { 502 int ret; 503 504 pr_info("Version " VERSION " at io 0x%X\n", 505 WDT_INDEX_IO_PORT); 506 507 if (!request_muxed_region(io, 2, MODNAME)) 508 return -EBUSY; 509 510 ret = register_reboot_notifier(&pc87413_notifier); 511 if (ret != 0) 512 pr_err("cannot register reboot notifier (err=%d)\n", ret); 513 514 ret = misc_register(&pc87413_miscdev); 515 if (ret != 0) { 516 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 517 WATCHDOG_MINOR, ret); 518 goto reboot_unreg; 519 } 520 pr_info("initialized. timeout=%d min\n", timeout); 521 522 pc87413_select_wdt_out(); 523 pc87413_enable_swc(); 524 pc87413_get_swc_base_addr(); 525 526 if (!request_region(swc_base_addr, 0x20, MODNAME)) { 527 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr); 528 ret = -EBUSY; 529 goto misc_unreg; 530 } 531 532 pc87413_enable(); 533 534 release_region(io, 2); 535 return 0; 536 537 misc_unreg: 538 misc_deregister(&pc87413_miscdev); 539 reboot_unreg: 540 unregister_reboot_notifier(&pc87413_notifier); 541 release_region(io, 2); 542 return ret; 543 } 544 545 /** 546 * pc87413_exit: module's "destructor" 547 * 548 * Unload the watchdog. You cannot do this with any file handles open. 549 * If your watchdog is set to continue ticking on close and you unload 550 * it, well it keeps ticking. We won't get the interrupt but the board 551 * will not touch PC memory so all is fine. You just have to load a new 552 * module in 60 seconds or reboot. 553 */ 554 555 static void __exit pc87413_exit(void) 556 { 557 /* Stop the timer before we leave */ 558 if (!nowayout) { 559 pc87413_disable(); 560 pr_info("Watchdog disabled\n"); 561 } 562 563 misc_deregister(&pc87413_miscdev); 564 unregister_reboot_notifier(&pc87413_notifier); 565 release_region(swc_base_addr, 0x20); 566 567 pr_info("watchdog component driver removed\n"); 568 } 569 570 module_init(pc87413_init); 571 module_exit(pc87413_exit); 572 573 MODULE_AUTHOR("Sven Anders <anders@anduras.de>"); 574 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>"); 575 MODULE_DESCRIPTION("PC87413 WDT driver"); 576 MODULE_LICENSE("GPL"); 577 578 module_param_hw(io, int, ioport, 0); 579 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " 580 __MODULE_STRING(IO_DEFAULT) ")."); 581 582 module_param(timeout, int, 0); 583 MODULE_PARM_DESC(timeout, 584 "Watchdog timeout in minutes (default=" 585 __MODULE_STRING(DEFAULT_TIMEOUT) ")."); 586 587 module_param(nowayout, bool, 0); 588 MODULE_PARM_DESC(nowayout, 589 "Watchdog cannot be stopped once started (default=" 590 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 591 592