drivers/watchdog/eurotechwdt.c

   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 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);