1 /* 2 * Eurotech CPU-1220/1410/1420 on board WDT driver 3 * 4 * (c) Copyright 2001 Ascensit <support@ascensit.com> 5 * (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com> 6 * (c) Copyright 2002 Rob Radez <rob@osinvestor.com> 7 * 8 * Based on wdt.c. 9 * Original copyright messages: 10 * 11 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, 12 * All Rights Reserved. 13 * 14 * This program is free software; you can redistribute it and/or 15 * modify it under the terms of the GNU General Public License 16 * as published by the Free Software Foundation; either version 17 * 2 of the License, or (at your option) any later version. 18 * 19 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 20 * warranty for any of this software. This material is provided 21 * "AS-IS" and at no charge. 22 * 23 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>* 24 */ 25 26 /* Changelog: 27 * 28 * 2001 - Rodolfo Giometti 29 * Initial release 30 * 31 * 2002/04/25 - Rob Radez 32 * clean up #includes 33 * clean up locking 34 * make __setup param unique 35 * proper options in watchdog_info 36 * add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls 37 * add expect_close support 38 * 39 * 2002.05.30 - Joel Becker <joel.becker@oracle.com> 40 * Added Matt Domsch's nowayout module option. 41 */ 42 43 /* 44 * The eurotech CPU-1220/1410/1420's watchdog is a part 45 * of the on-board SUPER I/O device SMSC FDC 37B782. 46 */ 47 48 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 49 50 #include <linux/interrupt.h> 51 #include <linux/module.h> 52 #include <linux/moduleparam.h> 53 #include <linux/types.h> 54 #include <linux/miscdevice.h> 55 #include <linux/watchdog.h> 56 #include <linux/fs.h> 57 #include <linux/ioport.h> 58 #include <linux/notifier.h> 59 #include <linux/reboot.h> 60 #include <linux/init.h> 61 #include <linux/io.h> 62 #include <linux/uaccess.h> 63 64 65 static unsigned long eurwdt_is_open; 66 static int eurwdt_timeout; 67 static char eur_expect_close; 68 static DEFINE_SPINLOCK(eurwdt_lock); 69 70 /* 71 * You must set these - there is no sane way to probe for this board. 72 */ 73 74 static int io = 0x3f0; 75 static int irq = 10; 76 static char *ev = "int"; 77 78 #define WDT_TIMEOUT 60 /* 1 minute */ 79 80 static bool nowayout = WATCHDOG_NOWAYOUT; 81 module_param(nowayout, bool, 0); 82 MODULE_PARM_DESC(nowayout, 83 "Watchdog cannot be stopped once started (default=" 84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 85 86 /* 87 * Some symbolic names 88 */ 89 90 #define WDT_CTRL_REG 0x30 91 #define WDT_OUTPIN_CFG 0xe2 92 #define WDT_EVENT_INT 0x00 93 #define WDT_EVENT_REBOOT 0x08 94 #define WDT_UNIT_SEL 0xf1 95 #define WDT_UNIT_SECS 0x80 96 #define WDT_TIMEOUT_VAL 0xf2 97 #define WDT_TIMER_CFG 0xf3 98 99 100 module_param(io, int, 0); 101 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)"); 102 module_param(irq, int, 0); 103 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)"); 104 module_param(ev, charp, 0); 105 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')"); 106 107 108 /* 109 * Programming support 110 */ 111 112 static inline void eurwdt_write_reg(u8 index, u8 data) 113 { 114 outb(index, io); 115 outb(data, io+1); 116 } 117 118 static inline void eurwdt_lock_chip(void) 119 { 120 outb(0xaa, io); 121 } 122 123 static inline void eurwdt_unlock_chip(void) 124 { 125 outb(0x55, io); 126 eurwdt_write_reg(0x07, 0x08); /* set the logical device */ 127 } 128 129 static inline void eurwdt_set_timeout(int timeout) 130 { 131 eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout); 132 } 133 134 static inline void eurwdt_disable_timer(void) 135 { 136 eurwdt_set_timeout(0); 137 } 138 139 static void eurwdt_activate_timer(void) 140 { 141 eurwdt_disable_timer(); 142 eurwdt_write_reg(WDT_CTRL_REG, 0x01); /* activate the WDT */ 143 eurwdt_write_reg(WDT_OUTPIN_CFG, 144 !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT); 145 146 /* Setting interrupt line */ 147 if (irq == 2 || irq > 15 || irq < 0) { 148 pr_err("invalid irq number\n"); 149 irq = 0; /* if invalid we disable interrupt */ 150 } 151 if (irq == 0) 152 pr_info("interrupt disabled\n"); 153 154 eurwdt_write_reg(WDT_TIMER_CFG, irq << 4); 155 156 eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */ 157 eurwdt_set_timeout(0); /* the default timeout */ 158 } 159 160 161 /* 162 * Kernel methods. 163 */ 164 165 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id) 166 { 167 pr_crit("timeout WDT timeout\n"); 168 169 #ifdef ONLY_TESTING 170 pr_crit("Would Reboot\n"); 171 #else 172 pr_crit("Initiating system reboot\n"); 173 emergency_restart(); 174 #endif 175 return IRQ_HANDLED; 176 } 177 178 179 /** 180 * eurwdt_ping: 181 * 182 * Reload counter one with the watchdog timeout. 183 */ 184 185 static void eurwdt_ping(void) 186 { 187 /* Write the watchdog default value */ 188 eurwdt_set_timeout(eurwdt_timeout); 189 } 190 191 /** 192 * eurwdt_write: 193 * @file: file handle to the watchdog 194 * @buf: buffer to write (unused as data does not matter here 195 * @count: count of bytes 196 * @ppos: pointer to the position to write. No seeks allowed 197 * 198 * A write to a watchdog device is defined as a keepalive signal. Any 199 * write of data will do, as we we don't define content meaning. 200 */ 201 202 static ssize_t eurwdt_write(struct file *file, const char __user *buf, 203 size_t count, loff_t *ppos) 204 { 205 if (count) { 206 if (!nowayout) { 207 size_t i; 208 209 eur_expect_close = 0; 210 211 for (i = 0; i != count; i++) { 212 char c; 213 if (get_user(c, buf + i)) 214 return -EFAULT; 215 if (c == 'V') 216 eur_expect_close = 42; 217 } 218 } 219 spin_lock(&eurwdt_lock); 220 eurwdt_ping(); /* the default timeout */ 221 spin_unlock(&eurwdt_lock); 222 } 223 return count; 224 } 225 226 /** 227 * eurwdt_ioctl: 228 * @file: file handle to the device 229 * @cmd: watchdog command 230 * @arg: argument pointer 231 * 232 * The watchdog API defines a common set of functions for all watchdogs 233 * according to their available features. 234 */ 235 236 static long eurwdt_ioctl(struct file *file, 237 unsigned int cmd, unsigned long arg) 238 { 239 void __user *argp = (void __user *)arg; 240 int __user *p = argp; 241 static const struct watchdog_info ident = { 242 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT 243 | WDIOF_MAGICCLOSE, 244 .firmware_version = 1, 245 .identity = "WDT Eurotech CPU-1220/1410", 246 }; 247 248 int time; 249 int options, retval = -EINVAL; 250 251 switch (cmd) { 252 case WDIOC_GETSUPPORT: 253 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 254 255 case WDIOC_GETSTATUS: 256 case WDIOC_GETBOOTSTATUS: 257 return put_user(0, p); 258 259 case WDIOC_SETOPTIONS: 260 if (get_user(options, p)) 261 return -EFAULT; 262 spin_lock(&eurwdt_lock); 263 if (options & WDIOS_DISABLECARD) { 264 eurwdt_disable_timer(); 265 retval = 0; 266 } 267 if (options & WDIOS_ENABLECARD) { 268 eurwdt_activate_timer(); 269 eurwdt_ping(); 270 retval = 0; 271 } 272 spin_unlock(&eurwdt_lock); 273 return retval; 274 275 case WDIOC_KEEPALIVE: 276 spin_lock(&eurwdt_lock); 277 eurwdt_ping(); 278 spin_unlock(&eurwdt_lock); 279 return 0; 280 281 case WDIOC_SETTIMEOUT: 282 if (copy_from_user(&time, p, sizeof(int))) 283 return -EFAULT; 284 285 /* Sanity check */ 286 if (time < 0 || time > 255) 287 return -EINVAL; 288 289 spin_lock(&eurwdt_lock); 290 eurwdt_timeout = time; 291 eurwdt_set_timeout(time); 292 spin_unlock(&eurwdt_lock); 293 /* Fall */ 294 295 case WDIOC_GETTIMEOUT: 296 return put_user(eurwdt_timeout, p); 297 298 default: 299 return -ENOTTY; 300 } 301 } 302 303 /** 304 * eurwdt_open: 305 * @inode: inode of device 306 * @file: file handle to device 307 * 308 * The misc device has been opened. The watchdog device is single 309 * open and on opening we load the counter. 310 */ 311 312 static int eurwdt_open(struct inode *inode, struct file *file) 313 { 314 if (test_and_set_bit(0, &eurwdt_is_open)) 315 return -EBUSY; 316 eurwdt_timeout = WDT_TIMEOUT; /* initial timeout */ 317 /* Activate the WDT */ 318 eurwdt_activate_timer(); 319 return nonseekable_open(inode, file); 320 } 321 322 /** 323 * eurwdt_release: 324 * @inode: inode to board 325 * @file: file handle to board 326 * 327 * The watchdog has a configurable API. There is a religious dispute 328 * between people who want their watchdog to be able to shut down and 329 * those who want to be sure if the watchdog manager dies the machine 330 * reboots. In the former case we disable the counters, in the latter 331 * case you have to open it again very soon. 332 */ 333 334 static int eurwdt_release(struct inode *inode, struct file *file) 335 { 336 if (eur_expect_close == 42) 337 eurwdt_disable_timer(); 338 else { 339 pr_crit("Unexpected close, not stopping watchdog!\n"); 340 eurwdt_ping(); 341 } 342 clear_bit(0, &eurwdt_is_open); 343 eur_expect_close = 0; 344 return 0; 345 } 346 347 /** 348 * eurwdt_notify_sys: 349 * @this: our notifier block 350 * @code: the event being reported 351 * @unused: unused 352 * 353 * Our notifier is called on system shutdowns. We want to turn the card 354 * off at reboot otherwise the machine will reboot again during memory 355 * test or worse yet during the following fsck. This would suck, in fact 356 * trust me - if it happens it does suck. 357 */ 358 359 static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code, 360 void *unused) 361 { 362 if (code == SYS_DOWN || code == SYS_HALT) 363 eurwdt_disable_timer(); /* Turn the card off */ 364 365 return NOTIFY_DONE; 366 } 367 368 /* 369 * Kernel Interfaces 370 */ 371 372 373 static const struct file_operations eurwdt_fops = { 374 .owner = THIS_MODULE, 375 .llseek = no_llseek, 376 .write = eurwdt_write, 377 .unlocked_ioctl = eurwdt_ioctl, 378 .open = eurwdt_open, 379 .release = eurwdt_release, 380 }; 381 382 static struct miscdevice eurwdt_miscdev = { 383 .minor = WATCHDOG_MINOR, 384 .name = "watchdog", 385 .fops = &eurwdt_fops, 386 }; 387 388 /* 389 * The WDT card needs to learn about soft shutdowns in order to 390 * turn the timebomb registers off. 391 */ 392 393 static struct notifier_block eurwdt_notifier = { 394 .notifier_call = eurwdt_notify_sys, 395 }; 396 397 /** 398 * cleanup_module: 399 * 400 * Unload the watchdog. You cannot do this with any file handles open. 401 * If your watchdog is set to continue ticking on close and you unload 402 * it, well it keeps ticking. We won't get the interrupt but the board 403 * will not touch PC memory so all is fine. You just have to load a new 404 * module in 60 seconds or reboot. 405 */ 406 407 static void __exit eurwdt_exit(void) 408 { 409 eurwdt_lock_chip(); 410 411 misc_deregister(&eurwdt_miscdev); 412 413 unregister_reboot_notifier(&eurwdt_notifier); 414 release_region(io, 2); 415 free_irq(irq, NULL); 416 } 417 418 /** 419 * eurwdt_init: 420 * 421 * Set up the WDT watchdog board. After grabbing the resources 422 * we require we need also to unlock the device. 423 * The open() function will actually kick the board off. 424 */ 425 426 static int __init eurwdt_init(void) 427 { 428 int ret; 429 430 ret = request_irq(irq, eurwdt_interrupt, 0, "eurwdt", NULL); 431 if (ret) { 432 pr_err("IRQ %d is not free\n", irq); 433 goto out; 434 } 435 436 if (!request_region(io, 2, "eurwdt")) { 437 pr_err("IO %X is not free\n", io); 438 ret = -EBUSY; 439 goto outirq; 440 } 441 442 ret = register_reboot_notifier(&eurwdt_notifier); 443 if (ret) { 444 pr_err("can't register reboot notifier (err=%d)\n", ret); 445 goto outreg; 446 } 447 448 ret = misc_register(&eurwdt_miscdev); 449 if (ret) { 450 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR); 451 goto outreboot; 452 } 453 454 eurwdt_unlock_chip(); 455 456 ret = 0; 457 pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n", 458 io, irq, (!strcmp("int", ev) ? "int" : "reboot")); 459 460 out: 461 return ret; 462 463 outreboot: 464 unregister_reboot_notifier(&eurwdt_notifier); 465 466 outreg: 467 release_region(io, 2); 468 469 outirq: 470 free_irq(irq, NULL); 471 goto out; 472 } 473 474 module_init(eurwdt_init); 475 module_exit(eurwdt_exit); 476 477 MODULE_AUTHOR("Rodolfo Giometti"); 478 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog"); 479 MODULE_LICENSE("GPL"); 480