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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  32
  33 #include <linux/module.h>
  34 #include <linux/moduleparam.h>
  35 #include <linux/types.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/watchdog.h>
  38 #include <linux/fs.h>
  39 #include <linux/ioport.h>
  40 #include <linux/platform_device.h>
  41 #include <linux/init.h>
  42 #include <linux/io.h>
  43 #include <linux/uaccess.h>
  44
  45
  46 #define DRV_NAME "advantechwdt"
  47 #define WATCHDOG_NAME "Advantech WDT"
  48 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  49
  50 /* the watchdog platform device */
  51 static struct platform_device *advwdt_platform_device;
  52 static unsigned long advwdt_is_open;
  53 static char adv_expect_close;
  54
  55 /*
  56  *      You must set these - there is no sane way to probe for this board.
  57  *
  58  *      To enable or restart, write the timeout value in seconds (1 to 63)
  59  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  60  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  61  *      check your manual (at least the PCA-6159 seems to be different -
  62  *      the manual says wdt_stop is 0x43, not 0x443).
  63  *      (0x43 is also a write-only control register for the 8254 timer!)
  64  */
  65
  66 static int wdt_stop = 0x443;
  67 module_param(wdt_stop, int, 0);
  68 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  69
  70 static int wdt_start = 0x443;
  71 module_param(wdt_start, int, 0);
  72 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  73
  74 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  75 module_param(timeout, int, 0);
  76 MODULE_PARM_DESC(timeout,
  77         "Watchdog timeout in seconds. 1<= timeout <=63, default="
  78                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  79
  80 static bool nowayout = WATCHDOG_NOWAYOUT;
  81 module_param(nowayout, bool, 0);
  82 MODULE_PARM_DESC(nowayout,
  83         "Watchdog cannot be stopped once started (default="
  84                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  85
  86 /*
  87  *      Watchdog Operations
  88  */
  89
  90 static void advwdt_ping(void)
  91 {
  92         /* Write a watchdog value */
  93         outb_p(timeout, wdt_start);
  94 }
  95
  96 static void advwdt_disable(void)
  97 {
  98         inb_p(wdt_stop);
  99 }
 100
 101 static int advwdt_set_heartbeat(int t)
 102 {
 103         if (t < 1 || t > 63)
 104                 return -EINVAL;
 105         timeout = t;
 106         return 0;
 107 }
 108
 109 /*
 110  *      /dev/watchdog handling
 111  */
 112
 113 static ssize_t advwdt_write(struct file *file, const char __user *buf,
 114                                                 size_t count, loff_t *ppos)
 115 {
 116         if (count) {
 117                 if (!nowayout) {
 118                         size_t i;
 119
 120                         adv_expect_close = 0;
 121
 122                         for (i = 0; i != count; i++) {
 123                                 char c;
 124                                 if (get_user(c, buf + i))
 125                                         return -EFAULT;
 126                                 if (c == 'V')
 127                                         adv_expect_close = 42;
 128                         }
 129                 }
 130                 advwdt_ping();
 131         }
 132         return count;
 133 }
 134
 135 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 136 {
 137         int new_timeout;
 138         void __user *argp = (void __user *)arg;
 139         int __user *p = argp;
 140         static const struct watchdog_info ident = {
 141                 .options = WDIOF_KEEPALIVEPING |
 142                            WDIOF_SETTIMEOUT |
 143                            WDIOF_MAGICCLOSE,
 144                 .firmware_version = 1,
 145                 .identity = WATCHDOG_NAME,
 146         };
 147
 148         switch (cmd) {
 149         case WDIOC_GETSUPPORT:
 150                 if (copy_to_user(argp, &ident, sizeof(ident)))
 151                         return -EFAULT;
 152                 break;
 153
 154         case WDIOC_GETSTATUS:
 155         case WDIOC_GETBOOTSTATUS:
 156                 return put_user(0, p);
 157
 158         case WDIOC_SETOPTIONS:
 159         {
 160                 int options, retval = -EINVAL;
 161
 162                 if (get_user(options, p))
 163                         return -EFAULT;
 164                 if (options & WDIOS_DISABLECARD) {
 165                         advwdt_disable();
 166                         retval = 0;
 167                 }
 168                 if (options & WDIOS_ENABLECARD) {
 169                         advwdt_ping();
 170                         retval = 0;
 171                 }
 172                 return retval;
 173         }
 174         case WDIOC_KEEPALIVE:
 175                 advwdt_ping();
 176                 break;
 177
 178         case WDIOC_SETTIMEOUT:
 179                 if (get_user(new_timeout, p))
 180                         return -EFAULT;
 181                 if (advwdt_set_heartbeat(new_timeout))
 182                         return -EINVAL;
 183                 advwdt_ping();
 184                 /* fall through */
 185         case WDIOC_GETTIMEOUT:
 186                 return put_user(timeout, p);
 187         default:
 188                 return -ENOTTY;
 189         }
 190         return 0;
 191 }
 192
 193 static int advwdt_open(struct inode *inode, struct file *file)
 194 {
 195         if (test_and_set_bit(0, &advwdt_is_open))
 196                 return -EBUSY;
 197         /*
 198          *      Activate
 199          */
 200
 201         advwdt_ping();
 202         return nonseekable_open(inode, file);
 203 }
 204
 205 static int advwdt_close(struct inode *inode, struct file *file)
 206 {
 207         if (adv_expect_close == 42) {
 208                 advwdt_disable();
 209         } else {
 210                 pr_crit("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 __init 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                         pr_err("I/O address 0x%04x already in use\n",
 248                                wdt_stop);
 249                         ret = -EIO;
 250                         goto out;
 251                 }
 252         }
 253
 254         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 255                 pr_err("I/O address 0x%04x already in use\n", wdt_start);
 256                 ret = -EIO;
 257                 goto unreg_stop;
 258         }
 259
 260         /* Check that the heartbeat value is within it's range ;
 261          * if not reset to the default */
 262         if (advwdt_set_heartbeat(timeout)) {
 263                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 264                 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
 265         }
 266
 267         ret = misc_register(&advwdt_miscdev);
 268         if (ret != 0) {
 269                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 270                        WATCHDOG_MINOR, ret);
 271                 goto unreg_regions;
 272         }
 273         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 274                 timeout, nowayout);
 275 out:
 276         return ret;
 277 unreg_regions:
 278         release_region(wdt_start, 1);
 279 unreg_stop:
 280         if (wdt_stop != wdt_start)
 281                 release_region(wdt_stop, 1);
 282         goto out;
 283 }
 284
 285 static int advwdt_remove(struct platform_device *dev)
 286 {
 287         misc_deregister(&advwdt_miscdev);
 288         release_region(wdt_start, 1);
 289         if (wdt_stop != wdt_start)
 290                 release_region(wdt_stop, 1);
 291
 292         return 0;
 293 }
 294
 295 static void advwdt_shutdown(struct platform_device *dev)
 296 {
 297         /* Turn the WDT off if we have a soft shutdown */
 298         advwdt_disable();
 299 }
 300
 301 static struct platform_driver advwdt_driver = {
 302         .remove         = advwdt_remove,
 303         .shutdown       = advwdt_shutdown,
 304         .driver         = {
 305                 .name   = DRV_NAME,
 306         },
 307 };
 308
 309 static int __init advwdt_init(void)
 310 {
 311         int err;
 312
 313         pr_info("WDT driver for Advantech single board computer initialising\n");
 314
 315         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
 316                                                                 -1, NULL, 0);
 317         if (IS_ERR(advwdt_platform_device))
 318                 return PTR_ERR(advwdt_platform_device);
 319
 320         err = platform_driver_probe(&advwdt_driver, advwdt_probe);
 321         if (err)
 322                 goto unreg_platform_device;
 323
 324         return 0;
 325
 326 unreg_platform_device:
 327         platform_device_unregister(advwdt_platform_device);
 328         return err;
 329 }
 330
 331 static void __exit advwdt_exit(void)
 332 {
 333         platform_device_unregister(advwdt_platform_device);
 334         platform_driver_unregister(&advwdt_driver);
 335         pr_info("Watchdog Module Unloaded\n");
 336 }
 337
 338 module_init(advwdt_init);
 339 module_exit(advwdt_exit);
 340
 341 MODULE_LICENSE("GPL");
 342 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 343 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");