1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Eurotech CPU-1220/1410/1420 on board WDT driver 4 * 5 * (c) Copyright 2001 Ascensit <support@ascensit.com> 6 * (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com> 7 * (c) Copyright 2002 Rob Radez <rob@osinvestor.com> 8 * 9 * Based on wdt.c. 10 * Original copyright messages: 11 * 12 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, 13 * All Rights Reserved. 14 * 15 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 16 * warranty for any of this software. This material is provided 17 * "AS-IS" and at no charge. 18 * 19 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>* 20 */ 21 22 /* Changelog: 23 * 24 * 2001 - Rodolfo Giometti 25 * Initial release 26 * 27 * 2002/04/25 - Rob Radez 28 * clean up #includes 29 * clean up locking 30 * make __setup param unique 31 * proper options in watchdog_info 32 * add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls 33 * add expect_close support 34 * 35 * 2002.05.30 - Joel Becker <joel.becker@oracle.com> 36 * Added Matt Domsch's nowayout module option. 37 */ 38 39 /* 40 * The eurotech CPU-1220/1410/1420's watchdog is a part 41 * of the on-board SUPER I/O device SMSC FDC 37B782. 42 */ 43 44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 45 46 #include <linux/interrupt.h> 47 #include <linux/module.h> 48 #include <linux/moduleparam.h> 49 #include <linux/types.h> 50 #include <linux/miscdevice.h> 51 #include <linux/watchdog.h> 52 #include <linux/fs.h> 53 #include <linux/ioport.h> 54 #include <linux/notifier.h> 55 #include <linux/reboot.h> 56 #include <linux/init.h> 57 #include <linux/io.h> 58 #include <linux/uaccess.h> 59 60 61 static unsigned long eurwdt_is_open; 62 static int eurwdt_timeout; 63 static char eur_expect_close; 64 static DEFINE_SPINLOCK(eurwdt_lock); 65 66 /* 67 * You must set these - there is no sane way to probe for this board. 68 */ 69 70 static int io = 0x3f0; 71 static int irq = 10; 72 static char *ev = "int"; 73 74 #define WDT_TIMEOUT 60 /* 1 minute */ 75 76 static bool nowayout = WATCHDOG_NOWAYOUT; 77 module_param(nowayout, bool, 0); 78 MODULE_PARM_DESC(nowayout, 79 "Watchdog cannot be stopped once started (default=" 80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 81 82 /* 83 * Some symbolic names 84 */ 85 86 #define WDT_CTRL_REG 0x30 87 #define WDT_OUTPIN_CFG 0xe2 88 #define WDT_EVENT_INT 0x00 89 #define WDT_EVENT_REBOOT 0x08 90 #define WDT_UNIT_SEL 0xf1 91 #define WDT_UNIT_SECS 0x80 92 #define WDT_TIMEOUT_VAL 0xf2 93 #define WDT_TIMER_CFG 0xf3 94 95 96 module_param_hw(io, int, ioport, 0); 97 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)"); 98 module_param_hw(irq, int, irq, 0); 99 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)"); 100 module_param(ev, charp, 0); 101 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')"); 102 103 104 /* 105 * Programming support 106 */ 107 108 static inline void eurwdt_write_reg(u8 index, u8 data) 109 { 110 outb(index, io); 111 outb(data, io+1); 112 } 113 114 static inline void eurwdt_lock_chip(void) 115 { 116 outb(0xaa, io); 117 } 118 119 static inline void eurwdt_unlock_chip(void) 120 { 121 outb(0x55, io); 122 eurwdt_write_reg(0x07, 0x08); /* set the logical device */ 123 } 124 125 static inline void eurwdt_set_timeout(int timeout) 126 { 127 eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout); 128 } 129 130 static inline void eurwdt_disable_timer(void) 131 { 132 eurwdt_set_timeout(0); 133 } 134 135 static void eurwdt_activate_timer(void) 136 { 137 eurwdt_disable_timer(); 138 eurwdt_write_reg(WDT_CTRL_REG, 0x01); /* activate the WDT */ 139 eurwdt_write_reg(WDT_OUTPIN_CFG, 140 !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT); 141 142 /* Setting interrupt line */ 143 if (irq == 2 || irq > 15 || irq < 0) { 144 pr_err("invalid irq number\n"); 145 irq = 0; /* if invalid we disable interrupt */ 146 } 147 if (irq == 0) 148 pr_info("interrupt disabled\n"); 149 150 eurwdt_write_reg(WDT_TIMER_CFG, irq << 4); 151 152 eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */ 153 eurwdt_set_timeout(0); /* the default timeout */ 154 } 155 156 157 /* 158 * Kernel methods. 159 */ 160 161 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id) 162 { 163 pr_crit("timeout WDT timeout\n"); 164 165 #ifdef ONLY_TESTING 166 pr_crit("Would Reboot\n"); 167 #else 168 pr_crit("Initiating system reboot\n"); 169 emergency_restart(); 170 #endif 171 return IRQ_HANDLED; 172 } 173 174 175 /** 176 * eurwdt_ping: 177 * 178 * Reload counter one with the watchdog timeout. 179 */ 180 181 static void eurwdt_ping(void) 182 { 183 /* Write the watchdog default value */ 184 eurwdt_set_timeout(eurwdt_timeout); 185 } 186 187 /** 188 * eurwdt_write: 189 * @file: file handle to the watchdog 190 * @buf: buffer to write (unused as data does not matter here 191 * @count: count of bytes 192 * @ppos: pointer to the position to write. No seeks allowed 193 * 194 * A write to a watchdog device is defined as a keepalive signal. Any 195 * write of data will do, as we we don't define content meaning. 196 */ 197 198 static ssize_t eurwdt_write(struct file *file, const char __user *buf, 199 size_t count, loff_t *ppos) 200 { 201 if (count) { 202 if (!nowayout) { 203 size_t i; 204 205 eur_expect_close = 0; 206 207 for (i = 0; i != count; i++) { 208 char c; 209 if (get_user(c, buf + i)) 210 return -EFAULT; 211 if (c == 'V') 212 eur_expect_close = 42; 213 } 214 } 215 spin_lock(&eurwdt_lock); 216 eurwdt_ping(); /* the default timeout */ 217 spin_unlock(&eurwdt_lock); 218 } 219 return count; 220 } 221 222 /** 223 * eurwdt_ioctl: 224 * @file: file handle to the device 225 * @cmd: watchdog command 226 * @arg: argument pointer 227 * 228 * The watchdog API defines a common set of functions for all watchdogs 229 * according to their available features. 230 */ 231 232 static long eurwdt_ioctl(struct file *file, 233 unsigned int cmd, unsigned long arg) 234 { 235 void __user *argp = (void __user *)arg; 236 int __user *p = argp; 237 static const struct watchdog_info ident = { 238 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT 239 | WDIOF_MAGICCLOSE, 240 .firmware_version = 1, 241 .identity = "WDT Eurotech CPU-1220/1410", 242 }; 243 244 int time; 245 int options, retval = -EINVAL; 246 247 switch (cmd) { 248 case WDIOC_GETSUPPORT: 249 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 250 251 case WDIOC_GETSTATUS: 252 case WDIOC_GETBOOTSTATUS: 253 return put_user(0, p); 254 255 case WDIOC_SETOPTIONS: 256 if (get_user(options, p)) 257 return -EFAULT; 258 spin_lock(&eurwdt_lock); 259 if (options & WDIOS_DISABLECARD) { 260 eurwdt_disable_timer(); 261 retval = 0; 262 } 263 if (options & WDIOS_ENABLECARD) { 264 eurwdt_activate_timer(); 265 eurwdt_ping(); 266 retval = 0; 267 } 268 spin_unlock(&eurwdt_lock); 269 return retval; 270 271 case WDIOC_KEEPALIVE: 272 spin_lock(&eurwdt_lock); 273 eurwdt_ping(); 274 spin_unlock(&eurwdt_lock); 275 return 0; 276 277 case WDIOC_SETTIMEOUT: 278 if (copy_from_user(&time, p, sizeof(int))) 279 return -EFAULT; 280 281 /* Sanity check */ 282 if (time < 0 || time > 255) 283 return -EINVAL; 284 285 spin_lock(&eurwdt_lock); 286 eurwdt_timeout = time; 287 eurwdt_set_timeout(time); 288 spin_unlock(&eurwdt_lock); 289 fallthrough; 290 291 case WDIOC_GETTIMEOUT: 292 return put_user(eurwdt_timeout, p); 293 294 default: 295 return -ENOTTY; 296 } 297 } 298 299 /** 300 * eurwdt_open: 301 * @inode: inode of device 302 * @file: file handle to device 303 * 304 * The misc device has been opened. The watchdog device is single 305 * open and on opening we load the counter. 306 */ 307 308 static int eurwdt_open(struct inode *inode, struct file *file) 309 { 310 if (test_and_set_bit(0, &eurwdt_is_open)) 311 return -EBUSY; 312 eurwdt_timeout = WDT_TIMEOUT; /* initial timeout */ 313 /* Activate the WDT */ 314 eurwdt_activate_timer(); 315 return stream_open(inode, file); 316 } 317 318 /** 319 * eurwdt_release: 320 * @inode: inode to board 321 * @file: file handle to board 322 * 323 * The watchdog has a configurable API. There is a religious dispute 324 * between people who want their watchdog to be able to shut down and 325 * those who want to be sure if the watchdog manager dies the machine 326 * reboots. In the former case we disable the counters, in the latter 327 * case you have to open it again very soon. 328 */ 329 330 static int eurwdt_release(struct inode *inode, struct file *file) 331 { 332 if (eur_expect_close == 42) 333 eurwdt_disable_timer(); 334 else { 335 pr_crit("Unexpected close, not stopping watchdog!\n"); 336 eurwdt_ping(); 337 } 338 clear_bit(0, &eurwdt_is_open); 339 eur_expect_close = 0; 340 return 0; 341 } 342 343 /** 344 * eurwdt_notify_sys: 345 * @this: our notifier block 346 * @code: the event being reported 347 * @unused: unused 348 * 349 * Our notifier is called on system shutdowns. We want to turn the card 350 * off at reboot otherwise the machine will reboot again during memory 351 * test or worse yet during the following fsck. This would suck, in fact 352 * trust me - if it happens it does suck. 353 */ 354 355 static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code, 356 void *unused) 357 { 358 if (code == SYS_DOWN || code == SYS_HALT) 359 eurwdt_disable_timer(); /* Turn the card off */ 360 361 return NOTIFY_DONE; 362 } 363 364 /* 365 * Kernel Interfaces 366 */ 367 368 369 static const struct file_operations eurwdt_fops = { 370 .owner = THIS_MODULE, 371 .llseek = no_llseek, 372 .write = eurwdt_write, 373 .unlocked_ioctl = eurwdt_ioctl, 374 .compat_ioctl = compat_ptr_ioctl, 375 .open = eurwdt_open, 376 .release = eurwdt_release, 377 }; 378 379 static struct miscdevice eurwdt_miscdev = { 380 .minor = WATCHDOG_MINOR, 381 .name = "watchdog", 382 .fops = &eurwdt_fops, 383 }; 384 385 /* 386 * The WDT card needs to learn about soft shutdowns in order to 387 * turn the timebomb registers off. 388 */ 389 390 static struct notifier_block eurwdt_notifier = { 391 .notifier_call = eurwdt_notify_sys, 392 }; 393 394 /** 395 * eurwdt_exit: 396 * 397 * Unload the watchdog. You cannot do this with any file handles open. 398 * If your watchdog is set to continue ticking on close and you unload 399 * it, well it keeps ticking. We won't get the interrupt but the board 400 * will not touch PC memory so all is fine. You just have to load a new 401 * module in 60 seconds or reboot. 402 */ 403 404 static void __exit eurwdt_exit(void) 405 { 406 eurwdt_lock_chip(); 407 408 misc_deregister(&eurwdt_miscdev); 409 410 unregister_reboot_notifier(&eurwdt_notifier); 411 release_region(io, 2); 412 free_irq(irq, NULL); 413 } 414 415 /** 416 * eurwdt_init: 417 * 418 * Set up the WDT watchdog board. After grabbing the resources 419 * we require we need also to unlock the device. 420 * The open() function will actually kick the board off. 421 */ 422 423 static int __init eurwdt_init(void) 424 { 425 int ret; 426 427 ret = request_irq(irq, eurwdt_interrupt, 0, "eurwdt", NULL); 428 if (ret) { 429 pr_err("IRQ %d is not free\n", irq); 430 goto out; 431 } 432 433 if (!request_region(io, 2, "eurwdt")) { 434 pr_err("IO %X is not free\n", io); 435 ret = -EBUSY; 436 goto outirq; 437 } 438 439 ret = register_reboot_notifier(&eurwdt_notifier); 440 if (ret) { 441 pr_err("can't register reboot notifier (err=%d)\n", ret); 442 goto outreg; 443 } 444 445 ret = misc_register(&eurwdt_miscdev); 446 if (ret) { 447 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR); 448 goto outreboot; 449 } 450 451 eurwdt_unlock_chip(); 452 453 ret = 0; 454 pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n", 455 io, irq, (!strcmp("int", ev) ? "int" : "reboot")); 456 457 out: 458 return ret; 459 460 outreboot: 461 unregister_reboot_notifier(&eurwdt_notifier); 462 463 outreg: 464 release_region(io, 2); 465 466 outirq: 467 free_irq(irq, NULL); 468 goto out; 469 } 470 471 module_init(eurwdt_init); 472 module_exit(eurwdt_exit); 473 474 MODULE_AUTHOR("Rodolfo Giometti"); 475 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog"); 476 MODULE_LICENSE("GPL"); 477