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 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  76 static int nowayout = 1;
  77 #else
  78 static int nowayout = 0;
  79 #endif
  80
  81 module_param(nowayout, int, 0);
  82 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  83
  84 /*
  85  * Some symbolic names
  86  */
  87
  88 #define WDT_CTRL_REG            0x30
  89 #define WDT_OUTPIN_CFG          0xe2
  90 #define WDT_EVENT_INT           0x00
  91 #define WDT_EVENT_REBOOT        0x08
  92 #define WDT_UNIT_SEL            0xf1
  93 #define WDT_UNIT_SECS           0x80
  94 #define WDT_TIMEOUT_VAL         0xf2
  95 #define WDT_TIMER_CFG           0xf3
  96
  97
  98 module_param(io, int, 0);
  99 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
 100 module_param(irq, int, 0);
 101 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
 102 module_param(ev, charp, 0);
 103 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
 104
 105
 106 /*
 107  * Programming support
 108  */
 109
 110 static inline void eurwdt_write_reg(u8 index, u8 data)
 111 {
 112         outb(index, io);
 113         outb(data, io+1);
 114 }
 115
 116 static inline void eurwdt_lock_chip(void)
 117 {
 118         outb(0xaa, io);
 119 }
 120
 121 static inline void eurwdt_unlock_chip(void)
 122 {
 123         outb(0x55, io);
 124         eurwdt_write_reg(0x07, 0x08);   /* set the logical device */
 125 }
 126
 127 static inline void eurwdt_set_timeout(int timeout)
 128 {
 129         eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
 130 }
 131
 132 static inline void eurwdt_disable_timer(void)
 133 {
 134         eurwdt_set_timeout(0);
 135 }
 136
 137 static void eurwdt_activate_timer(void)
 138 {
 139         eurwdt_disable_timer();
 140         eurwdt_write_reg(WDT_CTRL_REG, 0x01);   /* activate the WDT */
 141         eurwdt_write_reg(WDT_OUTPIN_CFG, !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
 142
 143         /* Setting interrupt line */
 144         if (irq == 2 || irq > 15 || irq < 0) {
 145                 printk(KERN_ERR ": invalid irq number\n");
 146                 irq = 0;        /* if invalid we disable interrupt */
 147         }
 148         if (irq == 0)
 149                 printk(KERN_INFO ": interrupt disabled\n");
 150
 151         eurwdt_write_reg(WDT_TIMER_CFG, irq<<4);
 152
 153         eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS);  /* we use seconds */
 154         eurwdt_set_timeout(0);  /* the default timeout */
 155 }
 156
 157
 158 /*
 159  * Kernel methods.
 160  */
 161
 162 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 163 {
 164         printk(KERN_CRIT "timeout WDT timeout\n");
 165
 166 #ifdef ONLY_TESTING
 167         printk(KERN_CRIT "Would Reboot.\n");
 168 #else
 169         printk(KERN_CRIT "Initiating system reboot.\n");
 170         machine_restart(NULL);
 171 #endif
 172         return IRQ_HANDLED;
 173 }
 174
 175
 176 /**
 177  * eurwdt_ping:
 178  *
 179  * Reload counter one with the watchdog timeout.
 180  */
 181
 182 static void eurwdt_ping(void)
 183 {
 184         /* Write the watchdog default value */
 185         eurwdt_set_timeout(eurwdt_timeout);
 186 }
 187
 188 /**
 189  * eurwdt_write:
 190  * @file: file handle to the watchdog
 191  * @buf: buffer to write (unused as data does not matter here
 192  * @count: count of bytes
 193  * @ppos: pointer to the position to write. No seeks allowed
 194  *
 195  * A write to a watchdog device is defined as a keepalive signal. Any
 196  * write of data will do, as we we don't define content meaning.
 197  */
 198
 199 static ssize_t eurwdt_write(struct file *file, const char __user *buf,
 200 size_t count, loff_t *ppos)
 201 {
 202         if (count)      {
 203                 if (!nowayout) {
 204                         size_t i;
 205
 206                         eur_expect_close = 0;
 207
 208                         for (i = 0; i != count; i++) {
 209                                 char c;
 210                                 if(get_user(c, buf+i))
 211                                         return -EFAULT;
 212                                 if (c == 'V')
 213                                         eur_expect_close = 42;
 214                         }
 215                 }
 216                 eurwdt_ping();  /* the default timeout */
 217         }
 218
 219         return count;
 220 }
 221
 222 /**
 223  * eurwdt_ioctl:
 224  * @inode: inode of the device
 225  * @file: file handle to the device
 226  * @cmd: watchdog command
 227  * @arg: argument pointer
 228  *
 229  * The watchdog API defines a common set of functions for all watchdogs
 230  * according to their available features.
 231  */
 232
 233 static int eurwdt_ioctl(struct inode *inode, struct file *file,
 234         unsigned int cmd, unsigned long arg)
 235 {
 236         void __user *argp = (void __user *)arg;
 237         int __user *p = argp;
 238         static struct watchdog_info ident = {
 239                 .options          = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 240                 .firmware_version = 1,
 241                 .identity         = "WDT Eurotech CPU-1220/1410",
 242         };
 243
 244         int time;
 245         int options, retval = -EINVAL;
 246
 247         switch(cmd) {
 248         default:
 249                 return -ENOIOCTLCMD;
 250
 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_KEEPALIVE:
 259                 eurwdt_ping();
 260                 return 0;
 261
 262         case WDIOC_SETTIMEOUT:
 263                 if (copy_from_user(&time, p, sizeof(int)))
 264                         return -EFAULT;
 265
 266                 /* Sanity check */
 267                 if (time < 0 || time > 255)
 268                         return -EINVAL;
 269
 270                 eurwdt_timeout = time;
 271                 eurwdt_set_timeout(time);
 272                 /* Fall */
 273
 274         case WDIOC_GETTIMEOUT:
 275                 return put_user(eurwdt_timeout, p);
 276
 277         case WDIOC_SETOPTIONS:
 278                 if (get_user(options, p))
 279                         return -EFAULT;
 280                 if (options & WDIOS_DISABLECARD) {
 281                         eurwdt_disable_timer();
 282                         retval = 0;
 283                 }
 284                 if (options & WDIOS_ENABLECARD) {
 285                         eurwdt_activate_timer();
 286                         eurwdt_ping();
 287                         retval = 0;
 288                 }
 289                 return retval;
 290         }
 291 }
 292
 293 /**
 294  * eurwdt_open:
 295  * @inode: inode of device
 296  * @file: file handle to device
 297  *
 298  * The misc device has been opened. The watchdog device is single
 299  * open and on opening we load the counter.
 300  */
 301
 302 static int eurwdt_open(struct inode *inode, struct file *file)
 303 {
 304         if (test_and_set_bit(0, &eurwdt_is_open))
 305                 return -EBUSY;
 306         eurwdt_timeout = WDT_TIMEOUT;   /* initial timeout */
 307         /* Activate the WDT */
 308         eurwdt_activate_timer();
 309         return nonseekable_open(inode, file);
 310 }
 311
 312 /**
 313  * eurwdt_release:
 314  * @inode: inode to board
 315  * @file: file handle to board
 316  *
 317  * The watchdog has a configurable API. There is a religious dispute
 318  * between people who want their watchdog to be able to shut down and
 319  * those who want to be sure if the watchdog manager dies the machine
 320  * reboots. In the former case we disable the counters, in the latter
 321  * case you have to open it again very soon.
 322  */
 323
 324 static int eurwdt_release(struct inode *inode, struct file *file)
 325 {
 326         if (eur_expect_close == 42) {
 327                 eurwdt_disable_timer();
 328         } else {
 329                 printk(KERN_CRIT "eurwdt: Unexpected close, not stopping watchdog!\n");
 330                 eurwdt_ping();
 331         }
 332         clear_bit(0, &eurwdt_is_open);
 333         eur_expect_close = 0;
 334         return 0;
 335 }
 336
 337 /**
 338  * eurwdt_notify_sys:
 339  * @this: our notifier block
 340  * @code: the event being reported
 341  * @unused: unused
 342  *
 343  * Our notifier is called on system shutdowns. We want to turn the card
 344  * off at reboot otherwise the machine will reboot again during memory
 345  * test or worse yet during the following fsck. This would suck, in fact
 346  * trust me - if it happens it does suck.
 347  */
 348
 349 static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code,
 350         void *unused)
 351 {
 352         if (code == SYS_DOWN || code == SYS_HALT) {
 353                 /* Turn the card off */
 354                 eurwdt_disable_timer();
 355         }
 356
 357         return NOTIFY_DONE;
 358 }
 359
 360 /*
 361  * Kernel Interfaces
 362  */
 363
 364
 365 static struct file_operations eurwdt_fops = {
 366         .owner  = THIS_MODULE,
 367         .llseek = no_llseek,
 368         .write  = eurwdt_write,
 369         .ioctl  = eurwdt_ioctl,
 370         .open   = eurwdt_open,
 371         .release        = eurwdt_release,
 372 };
 373
 374 static struct miscdevice eurwdt_miscdev = {
 375         .minor  = WATCHDOG_MINOR,
 376         .name   = "watchdog",
 377         .fops   = &eurwdt_fops,
 378 };
 379
 380 /*
 381  * The WDT card needs to learn about soft shutdowns in order to
 382  * turn the timebomb registers off.
 383  */
 384
 385 static struct notifier_block eurwdt_notifier = {
 386         .notifier_call = eurwdt_notify_sys,
 387 };
 388
 389 /**
 390  * cleanup_module:
 391  *
 392  * Unload the watchdog. You cannot do this with any file handles open.
 393  * If your watchdog is set to continue ticking on close and you unload
 394  * it, well it keeps ticking. We won't get the interrupt but the board
 395  * will not touch PC memory so all is fine. You just have to load a new
 396  * module in 60 seconds or reboot.
 397  */
 398
 399 static void __exit eurwdt_exit(void)
 400 {
 401         eurwdt_lock_chip();
 402
 403         misc_deregister(&eurwdt_miscdev);
 404
 405         unregister_reboot_notifier(&eurwdt_notifier);
 406         release_region(io, 2);
 407         free_irq(irq, NULL);
 408 }
 409
 410 /**
 411  * eurwdt_init:
 412  *
 413  * Set up the WDT watchdog board. After grabbing the resources
 414  * we require we need also to unlock the device.
 415  * The open() function will actually kick the board off.
 416  */
 417
 418 static int __init eurwdt_init(void)
 419 {
 420         int ret;
 421
 422         ret = misc_register(&eurwdt_miscdev);
 423         if (ret) {
 424                 printk(KERN_ERR "eurwdt: can't misc_register on minor=%d\n",
 425                 WATCHDOG_MINOR);
 426                 goto out;
 427         }
 428
 429         ret = request_irq(irq, eurwdt_interrupt, SA_INTERRUPT, "eurwdt", NULL);
 430         if(ret) {
 431                 printk(KERN_ERR "eurwdt: IRQ %d is not free.\n", irq);
 432                 goto outmisc;
 433         }
 434
 435         if (!request_region(io, 2, "eurwdt")) {
 436                 printk(KERN_ERR "eurwdt: IO %X is not free.\n", io);
 437                 ret = -EBUSY;
 438                 goto outirq;
 439         }
 440
 441         ret = register_reboot_notifier(&eurwdt_notifier);
 442         if (ret) {
 443                 printk(KERN_ERR "eurwdt: can't register reboot notifier (err=%d)\n", ret);
 444                 goto outreg;
 445         }
 446
 447         eurwdt_unlock_chip();
 448
 449         ret = 0;
 450         printk(KERN_INFO "Eurotech WDT driver 0.01 at %X (Interrupt %d)"
 451                 " - timeout event: %s\n",
 452                 io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
 453
 454 out:
 455         return ret;
 456
 457 outreg:
 458         release_region(io, 2);
 459
 460 outirq:
 461         free_irq(irq, NULL);
 462
 463 outmisc:
 464         misc_deregister(&eurwdt_miscdev);
 465         goto out;
 466 }
 467
 468 module_init(eurwdt_init);
 469 module_exit(eurwdt_exit);
 470
 471 MODULE_AUTHOR("Rodolfo Giometti");
 472 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
 473 MODULE_LICENSE("GPL");
 474 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);