drivers/watchdog/advantechwdt.c

   1 /*
   2  *      Advantech Single Board Computer WDT driver
   3  *
   4  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
   5  *
   6  *      Based on acquirewdt.c which is based on wdt.c.
   7  *      Original copyright messages:
   8  *
   9  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  10  *                                              All Rights Reserved.
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  *
  17  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  18  *      warranty for any of this software. This material is provided
  19  *      "AS-IS" and at no charge.
  20  *
  21  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
  22  *
  23  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  24  *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  25  *
  26  *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
  27  *          Clean up ioctls, clean up init + exit, add expect close support,
  28  *          add wdt_start and wdt_stop as parameters.
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/types.h>
  34 #include <linux/miscdevice.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/fs.h>
  37 #include <linux/ioport.h>
  38 #include <linux/platform_device.h>
  39 #include <linux/init.h>
  40 #include <linux/io.h>
  41 #include <linux/uaccess.h>
  42
  43
  44 #define DRV_NAME "advantechwdt"
  45 #define PFX DRV_NAME ": "
  46 #define WATCHDOG_NAME "Advantech WDT"
  47 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  48
  49 /* the watchdog platform device */
  50 static struct platform_device *advwdt_platform_device;
  51 static unsigned long advwdt_is_open;
  52 static char adv_expect_close;
  53
  54 /*
  55  *      You must set these - there is no sane way to probe for this board.
  56  *
  57  *      To enable or restart, write the timeout value in seconds (1 to 63)
  58  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  59  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  60  *      check your manual (at least the PCA-6159 seems to be different -
  61  *      the manual says wdt_stop is 0x43, not 0x443).
  62  *      (0x43 is also a write-only control register for the 8254 timer!)
  63  */
  64
  65 static int wdt_stop = 0x443;
  66 module_param(wdt_stop, int, 0);
  67 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  68
  69 static int wdt_start = 0x443;
  70 module_param(wdt_start, int, 0);
  71 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  72
  73 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  74 module_param(timeout, int, 0);
  75 MODULE_PARM_DESC(timeout,
  76         "Watchdog timeout in seconds. 1<= timeout <=63, default="
  77                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  78
  79 static int nowayout = WATCHDOG_NOWAYOUT;
  80 module_param(nowayout, int, 0);
  81 MODULE_PARM_DESC(nowayout,
  82         "Watchdog cannot be stopped once started (default="
  83                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  84
  85 /*
  86  *      Watchdog Operations
  87  */
  88
  89 static void advwdt_ping(void)
  90 {
  91         /* Write a watchdog value */
  92         outb_p(timeout, wdt_start);
  93 }
  94
  95 static void advwdt_disable(void)
  96 {
  97         inb_p(wdt_stop);
  98 }
  99
 100 static int advwdt_set_heartbeat(int t)
 101 {
 102         if (t < 1 || t > 63)
 103                 return -EINVAL;
 104         timeout = t;
 105         return 0;
 106 }
 107
 108 /*
 109  *      /dev/watchdog handling
 110  */
 111
 112 static ssize_t advwdt_write(struct file *file, const char __user *buf,
 113                                                 size_t count, loff_t *ppos)
 114 {
 115         if (count) {
 116                 if (!nowayout) {
 117                         size_t i;
 118
 119                         adv_expect_close = 0;
 120
 121                         for (i = 0; i != count; i++) {
 122                                 char c;
 123                                 if (get_user(c, buf + i))
 124                                         return -EFAULT;
 125                                 if (c == 'V')
 126                                         adv_expect_close = 42;
 127                         }
 128                 }
 129                 advwdt_ping();
 130         }
 131         return count;
 132 }
 133
 134 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 135 {
 136         int new_timeout;
 137         void __user *argp = (void __user *)arg;
 138         int __user *p = argp;
 139         static const struct watchdog_info ident = {
 140                 .options = WDIOF_KEEPALIVEPING |
 141                            WDIOF_SETTIMEOUT |
 142                            WDIOF_MAGICCLOSE,
 143                 .firmware_version = 1,
 144                 .identity = WATCHDOG_NAME,
 145         };
 146
 147         switch (cmd) {
 148         case WDIOC_GETSUPPORT:
 149                 if (copy_to_user(argp, &ident, sizeof(ident)))
 150                         return -EFAULT;
 151                 break;
 152
 153         case WDIOC_GETSTATUS:
 154         case WDIOC_GETBOOTSTATUS:
 155                 return put_user(0, p);
 156
 157         case WDIOC_SETOPTIONS:
 158         {
 159                 int options, retval = -EINVAL;
 160
 161                 if (get_user(options, p))
 162                         return -EFAULT;
 163                 if (options & WDIOS_DISABLECARD) {
 164                         advwdt_disable();
 165                         retval = 0;
 166                 }
 167                 if (options & WDIOS_ENABLECARD) {
 168                         advwdt_ping();
 169                         retval = 0;
 170                 }
 171                 return retval;
 172         }
 173         case WDIOC_KEEPALIVE:
 174                 advwdt_ping();
 175                 break;
 176
 177         case WDIOC_SETTIMEOUT:
 178                 if (get_user(new_timeout, p))
 179                         return -EFAULT;
 180                 if (advwdt_set_heartbeat(new_timeout))
 181                         return -EINVAL;
 182                 advwdt_ping();
 183                 /* Fall */
 184         case WDIOC_GETTIMEOUT:
 185                 return put_user(timeout, p);
 186         default:
 187                 return -ENOTTY;
 188         }
 189         return 0;
 190 }
 191
 192 static int advwdt_open(struct inode *inode, struct file *file)
 193 {
 194         if (test_and_set_bit(0, &advwdt_is_open))
 195                 return -EBUSY;
 196         /*
 197          *      Activate
 198          */
 199
 200         advwdt_ping();
 201         return nonseekable_open(inode, file);
 202 }
 203
 204 static int advwdt_close(struct inode *inode, struct file *file)
 205 {
 206         if (adv_expect_close == 42) {
 207                 advwdt_disable();
 208         } else {
 209                 printk(KERN_CRIT PFX
 210                                 "Unexpected close, not stopping watchdog!\n");
 211                 advwdt_ping();
 212         }
 213         clear_bit(0, &advwdt_is_open);
 214         adv_expect_close = 0;
 215         return 0;
 216 }
 217
 218 /*
 219  *      Kernel Interfaces
 220  */
 221
 222 static const struct file_operations advwdt_fops = {
 223         .owner          = THIS_MODULE,
 224         .llseek         = no_llseek,
 225         .write          = advwdt_write,
 226         .unlocked_ioctl = advwdt_ioctl,
 227         .open           = advwdt_open,
 228         .release        = advwdt_close,
 229 };
 230
 231 static struct miscdevice advwdt_miscdev = {
 232         .minor  = WATCHDOG_MINOR,
 233         .name   = "watchdog",
 234         .fops   = &advwdt_fops,
 235 };
 236
 237 /*
 238  *      Init & exit routines
 239  */
 240
 241 static int __devinit advwdt_probe(struct platform_device *dev)
 242 {
 243         int ret;
 244
 245         if (wdt_stop != wdt_start) {
 246                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 247                         printk(KERN_ERR PFX
 248                                 "I/O address 0x%04x already in use\n",
 249                                                                 wdt_stop);
 250                         ret = -EIO;
 251                         goto out;
 252                 }
 253         }
 254
 255         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 256                 printk(KERN_ERR PFX
 257                                 "I/O address 0x%04x already in use\n",
 258                                                                 wdt_start);
 259                 ret = -EIO;
 260                 goto unreg_stop;
 261         }
 262
 263         /* Check that the heartbeat value is within it's range ;
 264          * if not reset to the default */
 265         if (advwdt_set_heartbeat(timeout)) {
 266                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 267                 printk(KERN_INFO PFX
 268                         "timeout value must be 1<=x<=63, using %d\n", timeout);
 269         }
 270
 271         ret = misc_register(&advwdt_miscdev);
 272         if (ret != 0) {
 273                 printk(KERN_ERR PFX
 274                         "cannot register miscdev on minor=%d (err=%d)\n",
 275                                                         WATCHDOG_MINOR, ret);
 276                 goto unreg_regions;
 277         }
 278         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 279                 timeout, nowayout);
 280 out:
 281         return ret;
 282 unreg_regions:
 283         release_region(wdt_start, 1);
 284 unreg_stop:
 285         if (wdt_stop != wdt_start)
 286                 release_region(wdt_stop, 1);
 287         goto out;
 288 }
 289
 290 static int __devexit advwdt_remove(struct platform_device *dev)
 291 {
 292         misc_deregister(&advwdt_miscdev);
 293         release_region(wdt_start, 1);
 294         if (wdt_stop != wdt_start)
 295                 release_region(wdt_stop, 1);
 296
 297         return 0;
 298 }
 299
 300 static void advwdt_shutdown(struct platform_device *dev)
 301 {
 302         /* Turn the WDT off if we have a soft shutdown */
 303         advwdt_disable();
 304 }
 305
 306 static struct platform_driver advwdt_driver = {
 307         .probe          = advwdt_probe,
 308         .remove         = __devexit_p(advwdt_remove),
 309         .shutdown       = advwdt_shutdown,
 310         .driver         = {
 311                 .owner  = THIS_MODULE,
 312                 .name   = DRV_NAME,
 313         },
 314 };
 315
 316 static int __init advwdt_init(void)
 317 {
 318         int err;
 319
 320         printk(KERN_INFO
 321              "WDT driver for Advantech single board computer initialising.\n");
 322
 323         err = platform_driver_register(&advwdt_driver);
 324         if (err)
 325                 return err;
 326
 327         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
 328                                                                 -1, NULL, 0);
 329         if (IS_ERR(advwdt_platform_device)) {
 330                 err = PTR_ERR(advwdt_platform_device);
 331                 goto unreg_platform_driver;
 332         }
 333
 334         return 0;
 335
 336 unreg_platform_driver:
 337         platform_driver_unregister(&advwdt_driver);
 338         return err;
 339 }
 340
 341 static void __exit advwdt_exit(void)
 342 {
 343         platform_device_unregister(advwdt_platform_device);
 344         platform_driver_unregister(&advwdt_driver);
 345         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 346 }
 347
 348 module_init(advwdt_init);
 349 module_exit(advwdt_exit);
 350
 351 MODULE_LICENSE("GPL");
 352 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 353 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
 354 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);