drivers/char/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@redhat.com>, All Rights Reserved.
  12  *                              http://www.redhat.com
  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
  60 #include <asm/io.h>
  61 #include <asm/uaccess.h>
  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
  68 /*
  69  * You must set these - there is no sane way to probe for this board.
  70  * You can use eurwdt=x,y to set these now.
  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, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  82
  83 /*
  84  * Some symbolic names
  85  */
  86
  87 #define WDT_CTRL_REG            0x30
  88 #define WDT_OUTPIN_CFG          0xe2
  89 #define WDT_EVENT_INT           0x00
  90 #define WDT_EVENT_REBOOT        0x08
  91 #define WDT_UNIT_SEL            0xf1
  92 #define WDT_UNIT_SECS           0x80
  93 #define WDT_TIMEOUT_VAL         0xf2
  94 #define WDT_TIMER_CFG           0xf3
  95
  96
  97 module_param(io, int, 0);
  98 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
  99 module_param(irq, int, 0);
 100 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
 101 module_param(ev, charp, 0);
 102 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
 103
 104
 105 /*
 106  * Programming support
 107  */
 108
 109 static inline void eurwdt_write_reg(u8 index, u8 data)
 110 {
 111         outb(index, io);
 112         outb(data, io+1);
 113 }
 114
 115 static inline void eurwdt_lock_chip(void)
 116 {
 117         outb(0xaa, io);
 118 }
 119
 120 static inline void eurwdt_unlock_chip(void)
 121 {
 122         outb(0x55, io);
 123         eurwdt_write_reg(0x07, 0x08);   /* set the logical device */
 124 }
 125
 126 static inline void eurwdt_set_timeout(int timeout)
 127 {
 128         eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
 129 }
 130
 131 static inline void eurwdt_disable_timer(void)
 132 {
 133         eurwdt_set_timeout(0);
 134 }
 135
 136 static void eurwdt_activate_timer(void)
 137 {
 138         eurwdt_disable_timer();
 139         eurwdt_write_reg(WDT_CTRL_REG, 0x01);   /* activate the WDT */
 140         eurwdt_write_reg(WDT_OUTPIN_CFG, !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
 141
 142         /* Setting interrupt line */
 143         if (irq == 2 || irq > 15 || irq < 0) {
 144                 printk(KERN_ERR ": invalid irq number\n");
 145                 irq = 0;        /* if invalid we disable interrupt */
 146         }
 147         if (irq == 0)
 148                 printk(KERN_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         printk(KERN_CRIT "timeout WDT timeout\n");
 164
 165 #ifdef ONLY_TESTING
 166         printk(KERN_CRIT "Would Reboot.\n");
 167 #else
 168         printk(KERN_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                 eurwdt_ping();  /* the default timeout */
 216         }
 217
 218         return count;
 219 }
 220
 221 /**
 222  * eurwdt_ioctl:
 223  * @inode: inode of the device
 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 int eurwdt_ioctl(struct inode *inode, 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 struct watchdog_info ident = {
 238                 .options          = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 239                 .firmware_version = 1,
 240                 .identity         = "WDT Eurotech CPU-1220/1410",
 241         };
 242
 243         int time;
 244         int options, retval = -EINVAL;
 245
 246         switch(cmd) {
 247         default:
 248                 return -ENOTTY;
 249
 250         case WDIOC_GETSUPPORT:
 251                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 252
 253         case WDIOC_GETSTATUS:
 254         case WDIOC_GETBOOTSTATUS:
 255                 return put_user(0, p);
 256
 257         case WDIOC_KEEPALIVE:
 258                 eurwdt_ping();
 259                 return 0;
 260
 261         case WDIOC_SETTIMEOUT:
 262                 if (copy_from_user(&time, p, sizeof(int)))
 263                         return -EFAULT;
 264
 265                 /* Sanity check */
 266                 if (time < 0 || time > 255)
 267                         return -EINVAL;
 268
 269                 eurwdt_timeout = time;
 270                 eurwdt_set_timeout(time);
 271                 /* Fall */
 272
 273         case WDIOC_GETTIMEOUT:
 274                 return put_user(eurwdt_timeout, p);
 275
 276         case WDIOC_SETOPTIONS:
 277                 if (get_user(options, p))
 278                         return -EFAULT;
 279                 if (options & WDIOS_DISABLECARD) {
 280                         eurwdt_disable_timer();
 281                         retval = 0;
 282                 }
 283                 if (options & WDIOS_ENABLECARD) {
 284                         eurwdt_activate_timer();
 285                         eurwdt_ping();
 286                         retval = 0;
 287                 }
 288                 return retval;
 289         }
 290 }
 291
 292 /**
 293  * eurwdt_open:
 294  * @inode: inode of device
 295  * @file: file handle to device
 296  *
 297  * The misc device has been opened. The watchdog device is single
 298  * open and on opening we load the counter.
 299  */
 300
 301 static int eurwdt_open(struct inode *inode, struct file *file)
 302 {
 303         if (test_and_set_bit(0, &eurwdt_is_open))
 304                 return -EBUSY;
 305         eurwdt_timeout = WDT_TIMEOUT;   /* initial timeout */
 306         /* Activate the WDT */
 307         eurwdt_activate_timer();
 308         return nonseekable_open(inode, file);
 309 }
 310
 311 /**
 312  * eurwdt_release:
 313  * @inode: inode to board
 314  * @file: file handle to board
 315  *
 316  * The watchdog has a configurable API. There is a religious dispute
 317  * between people who want their watchdog to be able to shut down and
 318  * those who want to be sure if the watchdog manager dies the machine
 319  * reboots. In the former case we disable the counters, in the latter
 320  * case you have to open it again very soon.
 321  */
 322
 323 static int eurwdt_release(struct inode *inode, struct file *file)
 324 {
 325         if (eur_expect_close == 42) {
 326                 eurwdt_disable_timer();
 327         } else {
 328                 printk(KERN_CRIT "eurwdt: Unexpected close, not stopping watchdog!\n");
 329                 eurwdt_ping();
 330         }
 331         clear_bit(0, &eurwdt_is_open);
 332         eur_expect_close = 0;
 333         return 0;
 334 }
 335
 336 /**
 337  * eurwdt_notify_sys:
 338  * @this: our notifier block
 339  * @code: the event being reported
 340  * @unused: unused
 341  *
 342  * Our notifier is called on system shutdowns. We want to turn the card
 343  * off at reboot otherwise the machine will reboot again during memory
 344  * test or worse yet during the following fsck. This would suck, in fact
 345  * trust me - if it happens it does suck.
 346  */
 347
 348 static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code,
 349         void *unused)
 350 {
 351         if (code == SYS_DOWN || code == SYS_HALT) {
 352                 /* Turn the card off */
 353                 eurwdt_disable_timer();
 354         }
 355
 356         return NOTIFY_DONE;
 357 }
 358
 359 /*
 360  * Kernel Interfaces
 361  */
 362
 363
 364 static const struct file_operations eurwdt_fops = {
 365         .owner  = THIS_MODULE,
 366         .llseek = no_llseek,
 367         .write  = eurwdt_write,
 368         .ioctl  = eurwdt_ioctl,
 369         .open   = eurwdt_open,
 370         .release        = eurwdt_release,
 371 };
 372
 373 static struct miscdevice eurwdt_miscdev = {
 374         .minor  = WATCHDOG_MINOR,
 375         .name   = "watchdog",
 376         .fops   = &eurwdt_fops,
 377 };
 378
 379 /*
 380  * The WDT card needs to learn about soft shutdowns in order to
 381  * turn the timebomb registers off.
 382  */
 383
 384 static struct notifier_block eurwdt_notifier = {
 385         .notifier_call = eurwdt_notify_sys,
 386 };
 387
 388 /**
 389  * cleanup_module:
 390  *
 391  * Unload the watchdog. You cannot do this with any file handles open.
 392  * If your watchdog is set to continue ticking on close and you unload
 393  * it, well it keeps ticking. We won't get the interrupt but the board
 394  * will not touch PC memory so all is fine. You just have to load a new
 395  * module in 60 seconds or reboot.
 396  */
 397
 398 static void __exit eurwdt_exit(void)
 399 {
 400         eurwdt_lock_chip();
 401
 402         misc_deregister(&eurwdt_miscdev);
 403
 404         unregister_reboot_notifier(&eurwdt_notifier);
 405         release_region(io, 2);
 406         free_irq(irq, NULL);
 407 }
 408
 409 /**
 410  * eurwdt_init:
 411  *
 412  * Set up the WDT watchdog board. After grabbing the resources
 413  * we require we need also to unlock the device.
 414  * The open() function will actually kick the board off.
 415  */
 416
 417 static int __init eurwdt_init(void)
 418 {
 419         int ret;
 420
 421         ret = request_irq(irq, eurwdt_interrupt, IRQF_DISABLED, "eurwdt", NULL);
 422         if(ret) {
 423                 printk(KERN_ERR "eurwdt: IRQ %d is not free.\n", irq);
 424                 goto out;
 425         }
 426
 427         if (!request_region(io, 2, "eurwdt")) {
 428                 printk(KERN_ERR "eurwdt: IO %X is not free.\n", io);
 429                 ret = -EBUSY;
 430                 goto outirq;
 431         }
 432
 433         ret = register_reboot_notifier(&eurwdt_notifier);
 434         if (ret) {
 435                 printk(KERN_ERR "eurwdt: can't register reboot notifier (err=%d)\n", ret);
 436                 goto outreg;
 437         }
 438
 439         ret = misc_register(&eurwdt_miscdev);
 440         if (ret) {
 441                 printk(KERN_ERR "eurwdt: can't misc_register on minor=%d\n",
 442                 WATCHDOG_MINOR);
 443                 goto outreboot;
 444         }
 445
 446         eurwdt_unlock_chip();
 447
 448         ret = 0;
 449         printk(KERN_INFO "Eurotech WDT driver 0.01 at %X (Interrupt %d)"
 450                 " - timeout event: %s\n",
 451                 io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
 452
 453 out:
 454         return ret;
 455
 456 outreboot:
 457         unregister_reboot_notifier(&eurwdt_notifier);
 458
 459 outreg:
 460         release_region(io, 2);
 461
 462 outirq:
 463         free_irq(irq, NULL);
 464         goto out;
 465 }
 466
 467 module_init(eurwdt_init);
 468 module_exit(eurwdt_exit);
 469
 470 MODULE_AUTHOR("Rodolfo Giometti");
 471 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
 472 MODULE_LICENSE("GPL");
 473 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);