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 #include <linux/interrupt.h>
  49 #include <linux/module.h>
  50 #include <linux/moduleparam.h>
  51 #include <linux/types.h>
  52 #include <linux/miscdevice.h>
  53 #include <linux/watchdog.h>
  54 #include <linux/fs.h>
  55 #include <linux/ioport.h>
  56 #include <linux/notifier.h>
  57 #include <linux/reboot.h>
  58 #include <linux/init.h>
  59 #include <linux/io.h>
  60 #include <linux/uaccess.h>
  61
  62 #include <asm/system.h>
  63
  64 static unsigned long eurwdt_is_open;
  65 static int eurwdt_timeout;
  66 static char eur_expect_close;
  67 static spinlock_t eurwdt_lock;
  68
  69 /*
  70  * You must set these - there is no sane way to probe for this board.
  71  */
  72
  73 static int io = 0x3f0;
  74 static int irq = 10;
  75 static char *ev = "int";
  76
  77 #define WDT_TIMEOUT             60                /* 1 minute */
  78
  79 static int nowayout = WATCHDOG_NOWAYOUT;
  80 module_param(nowayout, int, 0);
  81 MODULE_PARM_DESC(nowayout,
  82                 "Watchdog cannot be stopped once started (default="
  83                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  84
  85 /*
  86  * Some symbolic names
  87  */
  88
  89 #define WDT_CTRL_REG            0x30
  90 #define WDT_OUTPIN_CFG          0xe2
  91 #define WDT_EVENT_INT           0x00
  92 #define WDT_EVENT_REBOOT        0x08
  93 #define WDT_UNIT_SEL            0xf1
  94 #define WDT_UNIT_SECS           0x80
  95 #define WDT_TIMEOUT_VAL         0xf2
  96 #define WDT_TIMER_CFG           0xf3
  97
  98
  99 module_param(io, int, 0);
 100 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
 101 module_param(irq, int, 0);
 102 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
 103 module_param(ev, charp, 0);
 104 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
 105
 106
 107 /*
 108  * Programming support
 109  */
 110
 111 static inline void eurwdt_write_reg(u8 index, u8 data)
 112 {
 113         outb(index, io);
 114         outb(data, io+1);
 115 }
 116
 117 static inline void eurwdt_lock_chip(void)
 118 {
 119         outb(0xaa, io);
 120 }
 121
 122 static inline void eurwdt_unlock_chip(void)
 123 {
 124         outb(0x55, io);
 125         eurwdt_write_reg(0x07, 0x08);   /* set the logical device */
 126 }
 127
 128 static inline void eurwdt_set_timeout(int timeout)
 129 {
 130         eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
 131 }
 132
 133 static inline void eurwdt_disable_timer(void)
 134 {
 135         eurwdt_set_timeout(0);
 136 }
 137
 138 static void eurwdt_activate_timer(void)
 139 {
 140         eurwdt_disable_timer();
 141         eurwdt_write_reg(WDT_CTRL_REG, 0x01);   /* activate the WDT */
 142         eurwdt_write_reg(WDT_OUTPIN_CFG,
 143                 !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
 144
 145         /* Setting interrupt line */
 146         if (irq == 2 || irq > 15 || irq < 0) {
 147                 printk(KERN_ERR ": invalid irq number\n");
 148                 irq = 0;        /* if invalid we disable interrupt */
 149         }
 150         if (irq == 0)
 151                 printk(KERN_INFO ": interrupt disabled\n");
 152
 153         eurwdt_write_reg(WDT_TIMER_CFG, irq << 4);
 154
 155         eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS);  /* we use seconds */
 156         eurwdt_set_timeout(0);  /* the default timeout */
 157 }
 158
 159
 160 /*
 161  * Kernel methods.
 162  */
 163
 164 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
 165 {
 166         printk(KERN_CRIT "timeout WDT timeout\n");
 167
 168 #ifdef ONLY_TESTING
 169         printk(KERN_CRIT "Would Reboot.\n");
 170 #else
 171         printk(KERN_CRIT "Initiating system reboot.\n");
 172         emergency_restart();
 173 #endif
 174         return IRQ_HANDLED;
 175 }
 176
 177
 178 /**
 179  * eurwdt_ping:
 180  *
 181  * Reload counter one with the watchdog timeout.
 182  */
 183
 184 static void eurwdt_ping(void)
 185 {
 186         /* Write the watchdog default value */
 187         eurwdt_set_timeout(eurwdt_timeout);
 188 }
 189
 190 /**
 191  * eurwdt_write:
 192  * @file: file handle to the watchdog
 193  * @buf: buffer to write (unused as data does not matter here
 194  * @count: count of bytes
 195  * @ppos: pointer to the position to write. No seeks allowed
 196  *
 197  * A write to a watchdog device is defined as a keepalive signal. Any
 198  * write of data will do, as we we don't define content meaning.
 199  */
 200
 201 static ssize_t eurwdt_write(struct file *file, const char __user *buf,
 202 size_t count, loff_t *ppos)
 203 {
 204         if (count) {
 205                 if (!nowayout) {
 206                         size_t i;
 207
 208                         eur_expect_close = 0;
 209
 210                         for (i = 0; i != count; i++) {
 211                                 char c;
 212                                 if (get_user(c, buf + i))
 213                                         return -EFAULT;
 214                                 if (c == 'V')
 215                                         eur_expect_close = 42;
 216                         }
 217                 }
 218                 spin_lock(&eurwdt_lock);
 219                 eurwdt_ping();  /* the default timeout */
 220                 spin_unlock(&eurwdt_lock);
 221         }
 222         return count;
 223 }
 224
 225 /**
 226  * eurwdt_ioctl:
 227  * @file: file handle to the device
 228  * @cmd: watchdog command
 229  * @arg: argument pointer
 230  *
 231  * The watchdog API defines a common set of functions for all watchdogs
 232  * according to their available features.
 233  */
 234
 235 static long eurwdt_ioctl(struct file *file,
 236                                         unsigned int cmd, unsigned long arg)
 237 {
 238         void __user *argp = (void __user *)arg;
 239         int __user *p = argp;
 240         static const struct watchdog_info ident = {
 241                 .options          = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 242                                                         | WDIOF_MAGICCLOSE,
 243                 .firmware_version = 1,
 244                 .identity         = "WDT Eurotech CPU-1220/1410",
 245         };
 246
 247         int time;
 248         int options, retval = -EINVAL;
 249
 250         switch (cmd) {
 251         case WDIOC_GETSUPPORT:
 252                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 253
 254         case WDIOC_GETSTATUS:
 255         case WDIOC_GETBOOTSTATUS:
 256                 return put_user(0, p);
 257
 258         case WDIOC_SETOPTIONS:
 259                 if (get_user(options, p))
 260                         return -EFAULT;
 261                 spin_lock(&eurwdt_lock);
 262                 if (options & WDIOS_DISABLECARD) {
 263                         eurwdt_disable_timer();
 264                         retval = 0;
 265                 }
 266                 if (options & WDIOS_ENABLECARD) {
 267                         eurwdt_activate_timer();
 268                         eurwdt_ping();
 269                         retval = 0;
 270                 }
 271                 spin_unlock(&eurwdt_lock);
 272                 return retval;
 273
 274         case WDIOC_KEEPALIVE:
 275                 spin_lock(&eurwdt_lock);
 276                 eurwdt_ping();
 277                 spin_unlock(&eurwdt_lock);
 278                 return 0;
 279
 280         case WDIOC_SETTIMEOUT:
 281                 if (copy_from_user(&time, p, sizeof(int)))
 282                         return -EFAULT;
 283
 284                 /* Sanity check */
 285                 if (time < 0 || time > 255)
 286                         return -EINVAL;
 287
 288                 spin_lock(&eurwdt_lock);
 289                 eurwdt_timeout = time;
 290                 eurwdt_set_timeout(time);
 291                 spin_unlock(&eurwdt_lock);
 292                 /* Fall */
 293
 294         case WDIOC_GETTIMEOUT:
 295                 return put_user(eurwdt_timeout, p);
 296
 297         default:
 298                 return -ENOTTY;
 299         }
 300 }
 301
 302 /**
 303  * eurwdt_open:
 304  * @inode: inode of device
 305  * @file: file handle to device
 306  *
 307  * The misc device has been opened. The watchdog device is single
 308  * open and on opening we load the counter.
 309  */
 310
 311 static int eurwdt_open(struct inode *inode, struct file *file)
 312 {
 313         if (test_and_set_bit(0, &eurwdt_is_open))
 314                 return -EBUSY;
 315         eurwdt_timeout = WDT_TIMEOUT;   /* initial timeout */
 316         /* Activate the WDT */
 317         eurwdt_activate_timer();
 318         return nonseekable_open(inode, file);
 319 }
 320
 321 /**
 322  * eurwdt_release:
 323  * @inode: inode to board
 324  * @file: file handle to board
 325  *
 326  * The watchdog has a configurable API. There is a religious dispute
 327  * between people who want their watchdog to be able to shut down and
 328  * those who want to be sure if the watchdog manager dies the machine
 329  * reboots. In the former case we disable the counters, in the latter
 330  * case you have to open it again very soon.
 331  */
 332
 333 static int eurwdt_release(struct inode *inode, struct file *file)
 334 {
 335         if (eur_expect_close == 42)
 336                 eurwdt_disable_timer();
 337         else {
 338                 printk(KERN_CRIT
 339                         "eurwdt: 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, IRQF_DISABLED, "eurwdt", NULL);
 431         if (ret) {
 432                 printk(KERN_ERR "eurwdt: IRQ %d is not free.\n", irq);
 433                 goto out;
 434         }
 435
 436         if (!request_region(io, 2, "eurwdt")) {
 437                 printk(KERN_ERR "eurwdt: 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                 printk(KERN_ERR
 445                     "eurwdt: can't register reboot notifier (err=%d)\n", ret);
 446                 goto outreg;
 447         }
 448
 449         spin_lock_init(&eurwdt_lock);
 450
 451         ret = misc_register(&eurwdt_miscdev);
 452         if (ret) {
 453                 printk(KERN_ERR "eurwdt: can't misc_register on minor=%d\n",
 454                 WATCHDOG_MINOR);
 455                 goto outreboot;
 456         }
 457
 458         eurwdt_unlock_chip();
 459
 460         ret = 0;
 461         printk(KERN_INFO "Eurotech WDT driver 0.01 at %X (Interrupt %d)"
 462                 " - timeout event: %s\n",
 463                 io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
 464
 465 out:
 466         return ret;
 467
 468 outreboot:
 469         unregister_reboot_notifier(&eurwdt_notifier);
 470
 471 outreg:
 472         release_region(io, 2);
 473
 474 outirq:
 475         free_irq(irq, NULL);
 476         goto out;
 477 }
 478
 479 module_init(eurwdt_init);
 480 module_exit(eurwdt_exit);
 481
 482 MODULE_AUTHOR("Rodolfo Giometti");
 483 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
 484 MODULE_LICENSE("GPL");
 485 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);