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