drivers/watchdog/ib700wdt.c

   1 /*
   2  *      IB700 Single Board Computer WDT driver
   3  *
   4  *      (c) Copyright 2001 Charles Howes <chowes@vsol.net>
   5  *
   6  *      Based on advantechwdt.c which is based on acquirewdt.c which
   7  *      is based on wdt.c.
   8  *
   9  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  10  *
  11  *      Based on acquirewdt.c which is based on wdt.c.
  12  *      Original copyright messages:
  13  *
  14  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  15  *                              http://www.redhat.com
  16  *
  17  *      This program is free software; you can redistribute it and/or
  18  *      modify it under the terms of the GNU General Public License
  19  *      as published by the Free Software Foundation; either version
  20  *      2 of the License, or (at your option) any later version.
  21  *
  22  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  23  *      warranty for any of this software. This material is provided
  24  *      "AS-IS" and at no charge.
  25  *
  26  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  27  *
  28  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  29  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  30  *           Added timeout module option to override default
  31  *
  32  */
  33
  34 #include <linux/module.h>
  35 #include <linux/types.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/watchdog.h>
  38 #include <linux/ioport.h>
  39 #include <linux/fs.h>
  40 #include <linux/init.h>
  41 #include <linux/spinlock.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/platform_device.h>
  44 #include <linux/io.h>
  45 #include <linux/uaccess.h>
  46
  47 #include <asm/system.h>
  48
  49 static struct platform_device *ibwdt_platform_device;
  50 static unsigned long ibwdt_is_open;
  51 static DEFINE_SPINLOCK(ibwdt_lock);
  52 static char expect_close;
  53
  54 /* Module information */
  55 #define DRV_NAME "ib700wdt"
  56 #define PFX DRV_NAME ": "
  57
  58 /*
  59  *
  60  * Watchdog Timer Configuration
  61  *
  62  * The function of the watchdog timer is to reset the system
  63  * automatically and is defined at I/O port 0443H.  To enable the
  64  * watchdog timer and allow the system to reset, write I/O port 0443H.
  65  * To disable the timer, write I/O port 0441H for the system to stop the
  66  * watchdog function.  The timer has a tolerance of 20% for its
  67  * intervals.
  68  *
  69  * The following describes how the timer should be programmed.
  70  *
  71  * Enabling Watchdog:
  72  * MOV AX,000FH (Choose the values from 0 to F)
  73  * MOV DX,0443H
  74  * OUT DX,AX
  75  *
  76  * Disabling Watchdog:
  77  * MOV AX,000FH (Any value is fine.)
  78  * MOV DX,0441H
  79  * OUT DX,AX
  80  *
  81  * Watchdog timer control table:
  82  * Level   Value  Time/sec | Level Value Time/sec
  83  *   1       F       0     |   9     7      16
  84  *   2       E       2     |   10    6      18
  85  *   3       D       4     |   11    5      20
  86  *   4       C       6     |   12    4      22
  87  *   5       B       8     |   13    3      24
  88  *   6       A       10    |   14    2      26
  89  *   7       9       12    |   15    1      28
  90  *   8       8       14    |   16    0      30
  91  *
  92  */
  93
  94 static int wd_times[] = {
  95         30,     /* 0x0 */
  96         28,     /* 0x1 */
  97         26,     /* 0x2 */
  98         24,     /* 0x3 */
  99         22,     /* 0x4 */
 100         20,     /* 0x5 */
 101         18,     /* 0x6 */
 102         16,     /* 0x7 */
 103         14,     /* 0x8 */
 104         12,     /* 0x9 */
 105         10,     /* 0xA */
 106         8,      /* 0xB */
 107         6,      /* 0xC */
 108         4,      /* 0xD */
 109         2,      /* 0xE */
 110         0,      /* 0xF */
 111 };
 112
 113 #define WDT_STOP 0x441
 114 #define WDT_START 0x443
 115
 116 /* Default timeout */
 117 #define WD_TIMO 0               /* 30 seconds +/- 20%, from table */
 118
 119 static int wd_margin = WD_TIMO;
 120
 121 static int nowayout = WATCHDOG_NOWAYOUT;
 122 module_param(nowayout, int, 0);
 123 MODULE_PARM_DESC(nowayout,
 124                 "Watchdog cannot be stopped once started (default="
 125                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 126
 127
 128 /*
 129  *      Watchdog Operations
 130  */
 131
 132 static void ibwdt_ping(void)
 133 {
 134         spin_lock(&ibwdt_lock);
 135
 136         /* Write a watchdog value */
 137         outb_p(wd_margin, WDT_START);
 138
 139         spin_unlock(&ibwdt_lock);
 140 }
 141
 142 static void ibwdt_disable(void)
 143 {
 144         spin_lock(&ibwdt_lock);
 145         outb_p(0, WDT_STOP);
 146         spin_unlock(&ibwdt_lock);
 147 }
 148
 149 static int ibwdt_set_heartbeat(int t)
 150 {
 151         int i;
 152
 153         if ((t < 0) || (t > 30))
 154                 return -EINVAL;
 155
 156         for (i = 0x0F; i > -1; i--)
 157                 if (wd_times[i] >= t)
 158                         break;
 159         wd_margin = i;
 160         return 0;
 161 }
 162
 163 /*
 164  *      /dev/watchdog handling
 165  */
 166
 167 static ssize_t ibwdt_write(struct file *file, const char __user *buf,
 168                                                 size_t count, loff_t *ppos)
 169 {
 170         if (count) {
 171                 if (!nowayout) {
 172                         size_t i;
 173
 174                         /* In case it was set long ago */
 175                         expect_close = 0;
 176
 177                         for (i = 0; i != count; i++) {
 178                                 char c;
 179                                 if (get_user(c, buf + i))
 180                                         return -EFAULT;
 181                                 if (c == 'V')
 182                                         expect_close = 42;
 183                         }
 184                 }
 185                 ibwdt_ping();
 186         }
 187         return count;
 188 }
 189
 190 static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 191 {
 192         int new_margin;
 193         void __user *argp = (void __user *)arg;
 194         int __user *p = argp;
 195
 196         static struct watchdog_info ident = {
 197                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 198                                                         | WDIOF_MAGICCLOSE,
 199                 .firmware_version = 1,
 200                 .identity = "IB700 WDT",
 201         };
 202
 203         switch (cmd) {
 204         case WDIOC_GETSUPPORT:
 205                 if (copy_to_user(argp, &ident, sizeof(ident)))
 206                         return -EFAULT;
 207                 break;
 208
 209         case WDIOC_GETSTATUS:
 210         case WDIOC_GETBOOTSTATUS:
 211                 return put_user(0, p);
 212
 213         case WDIOC_SETOPTIONS:
 214         {
 215                 int options, retval = -EINVAL;
 216
 217                 if (get_user(options, p))
 218                         return -EFAULT;
 219
 220                 if (options & WDIOS_DISABLECARD) {
 221                         ibwdt_disable();
 222                         retval = 0;
 223                 }
 224                 if (options & WDIOS_ENABLECARD) {
 225                         ibwdt_ping();
 226                         retval = 0;
 227                 }
 228                 return retval;
 229         }
 230         case WDIOC_KEEPALIVE:
 231                 ibwdt_ping();
 232                 break;
 233
 234         case WDIOC_SETTIMEOUT:
 235                 if (get_user(new_margin, p))
 236                         return -EFAULT;
 237                 if (ibwdt_set_heartbeat(new_margin))
 238                         return -EINVAL;
 239                 ibwdt_ping();
 240                 /* Fall */
 241
 242         case WDIOC_GETTIMEOUT:
 243                 return put_user(wd_times[wd_margin], p);
 244
 245         default:
 246                 return -ENOTTY;
 247         }
 248         return 0;
 249 }
 250
 251 static int ibwdt_open(struct inode *inode, struct file *file)
 252 {
 253         if (test_and_set_bit(0, &ibwdt_is_open))
 254                 return -EBUSY;
 255         if (nowayout)
 256                 __module_get(THIS_MODULE);
 257
 258         /* Activate */
 259         ibwdt_ping();
 260         return nonseekable_open(inode, file);
 261 }
 262
 263 static int ibwdt_close(struct inode *inode, struct file *file)
 264 {
 265         if (expect_close == 42) {
 266                 ibwdt_disable();
 267         } else {
 268                 printk(KERN_CRIT PFX
 269                      "WDT device closed unexpectedly.  WDT will not stop!\n");
 270                 ibwdt_ping();
 271         }
 272         clear_bit(0, &ibwdt_is_open);
 273         expect_close = 0;
 274         return 0;
 275 }
 276
 277 /*
 278  *      Kernel Interfaces
 279  */
 280
 281 static const struct file_operations ibwdt_fops = {
 282         .owner          = THIS_MODULE,
 283         .llseek         = no_llseek,
 284         .write          = ibwdt_write,
 285         .unlocked_ioctl = ibwdt_ioctl,
 286         .open           = ibwdt_open,
 287         .release        = ibwdt_close,
 288 };
 289
 290 static struct miscdevice ibwdt_miscdev = {
 291         .minor = WATCHDOG_MINOR,
 292         .name = "watchdog",
 293         .fops = &ibwdt_fops,
 294 };
 295
 296 /*
 297  *      Init & exit routines
 298  */
 299
 300 static int __devinit ibwdt_probe(struct platform_device *dev)
 301 {
 302         int res;
 303
 304 #if WDT_START != WDT_STOP
 305         if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
 306                 printk(KERN_ERR PFX "STOP method I/O %X is not available.\n",
 307                                                                 WDT_STOP);
 308                 res = -EIO;
 309                 goto out_nostopreg;
 310         }
 311 #endif
 312
 313         if (!request_region(WDT_START, 1, "IB700 WDT")) {
 314                 printk(KERN_ERR PFX "START method I/O %X is not available.\n",
 315                                                                 WDT_START);
 316                 res = -EIO;
 317                 goto out_nostartreg;
 318         }
 319
 320         res = misc_register(&ibwdt_miscdev);
 321         if (res) {
 322                 printk(KERN_ERR PFX "failed to register misc device\n");
 323                 goto out_nomisc;
 324         }
 325         return 0;
 326
 327 out_nomisc:
 328         release_region(WDT_START, 1);
 329 out_nostartreg:
 330 #if WDT_START != WDT_STOP
 331         release_region(WDT_STOP, 1);
 332 #endif
 333 out_nostopreg:
 334         return res;
 335 }
 336
 337 static int __devexit ibwdt_remove(struct platform_device *dev)
 338 {
 339         misc_deregister(&ibwdt_miscdev);
 340         release_region(WDT_START, 1);
 341 #if WDT_START != WDT_STOP
 342         release_region(WDT_STOP, 1);
 343 #endif
 344         return 0;
 345 }
 346
 347 static void ibwdt_shutdown(struct platform_device *dev)
 348 {
 349         /* Turn the WDT off if we have a soft shutdown */
 350         ibwdt_disable();
 351 }
 352
 353 static struct platform_driver ibwdt_driver = {
 354         .probe          = ibwdt_probe,
 355         .remove         = __devexit_p(ibwdt_remove),
 356         .shutdown       = ibwdt_shutdown,
 357         .driver         = {
 358                 .owner  = THIS_MODULE,
 359                 .name   = DRV_NAME,
 360         },
 361 };
 362
 363 static int __init ibwdt_init(void)
 364 {
 365         int err;
 366
 367         printk(KERN_INFO PFX
 368                 "WDT driver for IB700 single board computer initialising.\n");
 369
 370         err = platform_driver_register(&ibwdt_driver);
 371         if (err)
 372                 return err;
 373
 374         ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
 375                                                                 -1, NULL, 0);
 376         if (IS_ERR(ibwdt_platform_device)) {
 377                 err = PTR_ERR(ibwdt_platform_device);
 378                 goto unreg_platform_driver;
 379         }
 380
 381         return 0;
 382
 383 unreg_platform_driver:
 384         platform_driver_unregister(&ibwdt_driver);
 385         return err;
 386 }
 387
 388 static void __exit ibwdt_exit(void)
 389 {
 390         platform_device_unregister(ibwdt_platform_device);
 391         platform_driver_unregister(&ibwdt_driver);
 392         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 393 }
 394
 395 module_init(ibwdt_init);
 396 module_exit(ibwdt_exit);
 397
 398 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
 399 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
 400 MODULE_LICENSE("GPL");
 401 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 402
 403 /* end of ib700wdt.c */