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 #include <asm/system.h>
  46
  47 #define DRV_NAME "advantechwdt"
  48 #define WATCHDOG_NAME "Advantech WDT"
  49 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  50
  51 /* the watchdog platform device */
  52 static struct platform_device *advwdt_platform_device;
  53 static unsigned long advwdt_is_open;
  54 static char adv_expect_close;
  55
  56 /*
  57  *      You must set these - there is no sane way to probe for this board.
  58  *
  59  *      To enable or restart, write the timeout value in seconds (1 to 63)
  60  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  61  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  62  *      check your manual (at least the PCA-6159 seems to be different -
  63  *      the manual says wdt_stop is 0x43, not 0x443).
  64  *      (0x43 is also a write-only control register for the 8254 timer!)
  65  */
  66
  67 static int wdt_stop = 0x443;
  68 module_param(wdt_stop, int, 0);
  69 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  70
  71 static int wdt_start = 0x443;
  72 module_param(wdt_start, int, 0);
  73 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  74
  75 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  76 module_param(timeout, int, 0);
  77 MODULE_PARM_DESC(timeout,
  78         "Watchdog timeout in seconds. 1<= timeout <=63, default="
  79                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  80
  81 static int nowayout = WATCHDOG_NOWAYOUT;
  82 module_param(nowayout, int, 0);
  83 MODULE_PARM_DESC(nowayout,
  84         "Watchdog cannot be stopped once started (default="
  85                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  86
  87 /*
  88  *      Watchdog Operations
  89  */
  90
  91 static void advwdt_ping(void)
  92 {
  93         /* Write a watchdog value */
  94         outb_p(timeout, wdt_start);
  95 }
  96
  97 static void advwdt_disable(void)
  98 {
  99         inb_p(wdt_stop);
 100 }
 101
 102 static int advwdt_set_heartbeat(int t)
 103 {
 104         if (t < 1 || t > 63)
 105                 return -EINVAL;
 106         timeout = t;
 107         return 0;
 108 }
 109
 110 /*
 111  *      /dev/watchdog handling
 112  */
 113
 114 static ssize_t advwdt_write(struct file *file, const char __user *buf,
 115                                                 size_t count, loff_t *ppos)
 116 {
 117         if (count) {
 118                 if (!nowayout) {
 119                         size_t i;
 120
 121                         adv_expect_close = 0;
 122
 123                         for (i = 0; i != count; i++) {
 124                                 char c;
 125                                 if (get_user(c, buf + i))
 126                                         return -EFAULT;
 127                                 if (c == 'V')
 128                                         adv_expect_close = 42;
 129                         }
 130                 }
 131                 advwdt_ping();
 132         }
 133         return count;
 134 }
 135
 136 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 137 {
 138         int new_timeout;
 139         void __user *argp = (void __user *)arg;
 140         int __user *p = argp;
 141         static const struct watchdog_info ident = {
 142                 .options = WDIOF_KEEPALIVEPING |
 143                            WDIOF_SETTIMEOUT |
 144                            WDIOF_MAGICCLOSE,
 145                 .firmware_version = 1,
 146                 .identity = WATCHDOG_NAME,
 147         };
 148
 149         switch (cmd) {
 150         case WDIOC_GETSUPPORT:
 151                 if (copy_to_user(argp, &ident, sizeof(ident)))
 152                         return -EFAULT;
 153                 break;
 154
 155         case WDIOC_GETSTATUS:
 156         case WDIOC_GETBOOTSTATUS:
 157                 return put_user(0, p);
 158
 159         case WDIOC_SETOPTIONS:
 160         {
 161                 int options, retval = -EINVAL;
 162
 163                 if (get_user(options, p))
 164                         return -EFAULT;
 165                 if (options & WDIOS_DISABLECARD) {
 166                         advwdt_disable();
 167                         retval = 0;
 168                 }
 169                 if (options & WDIOS_ENABLECARD) {
 170                         advwdt_ping();
 171                         retval = 0;
 172                 }
 173                 return retval;
 174         }
 175         case WDIOC_KEEPALIVE:
 176                 advwdt_ping();
 177                 break;
 178
 179         case WDIOC_SETTIMEOUT:
 180                 if (get_user(new_timeout, p))
 181                         return -EFAULT;
 182                 if (advwdt_set_heartbeat(new_timeout))
 183                         return -EINVAL;
 184                 advwdt_ping();
 185                 /* Fall */
 186         case WDIOC_GETTIMEOUT:
 187                 return put_user(timeout, p);
 188         default:
 189                 return -ENOTTY;
 190         }
 191         return 0;
 192 }
 193
 194 static int advwdt_open(struct inode *inode, struct file *file)
 195 {
 196         if (test_and_set_bit(0, &advwdt_is_open))
 197                 return -EBUSY;
 198         /*
 199          *      Activate
 200          */
 201
 202         advwdt_ping();
 203         return nonseekable_open(inode, file);
 204 }
 205
 206 static int advwdt_close(struct inode *inode, struct file *file)
 207 {
 208         if (adv_expect_close == 42) {
 209                 advwdt_disable();
 210         } else {
 211                 pr_crit("Unexpected close, not stopping watchdog!\n");
 212                 advwdt_ping();
 213         }
 214         clear_bit(0, &advwdt_is_open);
 215         adv_expect_close = 0;
 216         return 0;
 217 }
 218
 219 /*
 220  *      Kernel Interfaces
 221  */
 222
 223 static const struct file_operations advwdt_fops = {
 224         .owner          = THIS_MODULE,
 225         .llseek         = no_llseek,
 226         .write          = advwdt_write,
 227         .unlocked_ioctl = advwdt_ioctl,
 228         .open           = advwdt_open,
 229         .release        = advwdt_close,
 230 };
 231
 232 static struct miscdevice advwdt_miscdev = {
 233         .minor  = WATCHDOG_MINOR,
 234         .name   = "watchdog",
 235         .fops   = &advwdt_fops,
 236 };
 237
 238 /*
 239  *      Init & exit routines
 240  */
 241
 242 static int __devinit advwdt_probe(struct platform_device *dev)
 243 {
 244         int ret;
 245
 246         if (wdt_stop != wdt_start) {
 247                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 248                         pr_err("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                 pr_err("I/O address 0x%04x already in use\n", wdt_start);
 257                 ret = -EIO;
 258                 goto unreg_stop;
 259         }
 260
 261         /* Check that the heartbeat value is within it's range ;
 262          * if not reset to the default */
 263         if (advwdt_set_heartbeat(timeout)) {
 264                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 265                 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
 266         }
 267
 268         ret = misc_register(&advwdt_miscdev);
 269         if (ret != 0) {
 270                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 271                        WATCHDOG_MINOR, ret);
 272                 goto unreg_regions;
 273         }
 274         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 275                 timeout, nowayout);
 276 out:
 277         return ret;
 278 unreg_regions:
 279         release_region(wdt_start, 1);
 280 unreg_stop:
 281         if (wdt_stop != wdt_start)
 282                 release_region(wdt_stop, 1);
 283         goto out;
 284 }
 285
 286 static int __devexit advwdt_remove(struct platform_device *dev)
 287 {
 288         misc_deregister(&advwdt_miscdev);
 289         release_region(wdt_start, 1);
 290         if (wdt_stop != wdt_start)
 291                 release_region(wdt_stop, 1);
 292
 293         return 0;
 294 }
 295
 296 static void advwdt_shutdown(struct platform_device *dev)
 297 {
 298         /* Turn the WDT off if we have a soft shutdown */
 299         advwdt_disable();
 300 }
 301
 302 static struct platform_driver advwdt_driver = {
 303         .probe          = advwdt_probe,
 304         .remove         = __devexit_p(advwdt_remove),
 305         .shutdown       = advwdt_shutdown,
 306         .driver         = {
 307                 .owner  = THIS_MODULE,
 308                 .name   = DRV_NAME,
 309         },
 310 };
 311
 312 static int __init advwdt_init(void)
 313 {
 314         int err;
 315
 316         pr_info("WDT driver for Advantech single board computer initialising\n");
 317
 318         err = platform_driver_register(&advwdt_driver);
 319         if (err)
 320                 return err;
 321
 322         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
 323                                                                 -1, NULL, 0);
 324         if (IS_ERR(advwdt_platform_device)) {
 325                 err = PTR_ERR(advwdt_platform_device);
 326                 goto unreg_platform_driver;
 327         }
 328
 329         return 0;
 330
 331 unreg_platform_driver:
 332         platform_driver_unregister(&advwdt_driver);
 333         return err;
 334 }
 335
 336 static void __exit advwdt_exit(void)
 337 {
 338         platform_device_unregister(advwdt_platform_device);
 339         platform_driver_unregister(&advwdt_driver);
 340         pr_info("Watchdog Module Unloaded\n");
 341 }
 342
 343 module_init(advwdt_init);
 344 module_exit(advwdt_exit);
 345
 346 MODULE_LICENSE("GPL");
 347 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 348 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
 349 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);