drivers/char/watchdog/eurotechwdt.c

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