drivers/watchdog/advantechwdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *      Advantech Single Board Computer WDT driver
   4  *
   5  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
   6  *
   7  *      Based on acquirewdt.c which is based on wdt.c.
   8  *      Original copyright messages:
   9  *
  10  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  11  *                                              All Rights Reserved.
  12  *
  13  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  14  *      warranty for any of this software. This material is provided
  15  *      "AS-IS" and at no charge.
  16  *
  17  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
  18  *
  19  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  20  *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  21  *
  22  *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
  23  *          Clean up ioctls, clean up init + exit, add expect close support,
  24  *          add wdt_start and wdt_stop as parameters.
  25  */
  26
  27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  28
  29 #include <linux/module.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/types.h>
  32 #include <linux/miscdevice.h>
  33 #include <linux/watchdog.h>
  34 #include <linux/fs.h>
  35 #include <linux/ioport.h>
  36 #include <linux/platform_device.h>
  37 #include <linux/init.h>
  38 #include <linux/io.h>
  39 #include <linux/uaccess.h>
  40
  41
  42 #define DRV_NAME "advantechwdt"
  43 #define WATCHDOG_NAME "Advantech WDT"
  44 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  45
  46 /* the watchdog platform device */
  47 static struct platform_device *advwdt_platform_device;
  48 static unsigned long advwdt_is_open;
  49 static char adv_expect_close;
  50
  51 /*
  52  *      You must set these - there is no sane way to probe for this board.
  53  *
  54  *      To enable or restart, write the timeout value in seconds (1 to 63)
  55  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  56  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  57  *      check your manual (at least the PCA-6159 seems to be different -
  58  *      the manual says wdt_stop is 0x43, not 0x443).
  59  *      (0x43 is also a write-only control register for the 8254 timer!)
  60  */
  61
  62 static int wdt_stop = 0x443;
  63 module_param(wdt_stop, int, 0);
  64 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  65
  66 static int wdt_start = 0x443;
  67 module_param(wdt_start, int, 0);
  68 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  69
  70 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  71 module_param(timeout, int, 0);
  72 MODULE_PARM_DESC(timeout,
  73         "Watchdog timeout in seconds. 1<= timeout <=63, default="
  74                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  75
  76 static bool nowayout = WATCHDOG_NOWAYOUT;
  77 module_param(nowayout, bool, 0);
  78 MODULE_PARM_DESC(nowayout,
  79         "Watchdog cannot be stopped once started (default="
  80                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  81
  82 /*
  83  *      Watchdog Operations
  84  */
  85
  86 static void advwdt_ping(void)
  87 {
  88         /* Write a watchdog value */
  89         outb_p(timeout, wdt_start);
  90 }
  91
  92 static void advwdt_disable(void)
  93 {
  94         inb_p(wdt_stop);
  95 }
  96
  97 static int advwdt_set_heartbeat(int t)
  98 {
  99         if (t < 1 || t > 63)
 100                 return -EINVAL;
 101         timeout = t;
 102         return 0;
 103 }
 104
 105 /*
 106  *      /dev/watchdog handling
 107  */
 108
 109 static ssize_t advwdt_write(struct file *file, const char __user *buf,
 110                                                 size_t count, loff_t *ppos)
 111 {
 112         if (count) {
 113                 if (!nowayout) {
 114                         size_t i;
 115
 116                         adv_expect_close = 0;
 117
 118                         for (i = 0; i != count; i++) {
 119                                 char c;
 120                                 if (get_user(c, buf + i))
 121                                         return -EFAULT;
 122                                 if (c == 'V')
 123                                         adv_expect_close = 42;
 124                         }
 125                 }
 126                 advwdt_ping();
 127         }
 128         return count;
 129 }
 130
 131 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 132 {
 133         int new_timeout;
 134         void __user *argp = (void __user *)arg;
 135         int __user *p = argp;
 136         static const struct watchdog_info ident = {
 137                 .options = WDIOF_KEEPALIVEPING |
 138                            WDIOF_SETTIMEOUT |
 139                            WDIOF_MAGICCLOSE,
 140                 .firmware_version = 1,
 141                 .identity = WATCHDOG_NAME,
 142         };
 143
 144         switch (cmd) {
 145         case WDIOC_GETSUPPORT:
 146                 if (copy_to_user(argp, &ident, sizeof(ident)))
 147                         return -EFAULT;
 148                 break;
 149
 150         case WDIOC_GETSTATUS:
 151         case WDIOC_GETBOOTSTATUS:
 152                 return put_user(0, p);
 153
 154         case WDIOC_SETOPTIONS:
 155         {
 156                 int options, retval = -EINVAL;
 157
 158                 if (get_user(options, p))
 159                         return -EFAULT;
 160                 if (options & WDIOS_DISABLECARD) {
 161                         advwdt_disable();
 162                         retval = 0;
 163                 }
 164                 if (options & WDIOS_ENABLECARD) {
 165                         advwdt_ping();
 166                         retval = 0;
 167                 }
 168                 return retval;
 169         }
 170         case WDIOC_KEEPALIVE:
 171                 advwdt_ping();
 172                 break;
 173
 174         case WDIOC_SETTIMEOUT:
 175                 if (get_user(new_timeout, p))
 176                         return -EFAULT;
 177                 if (advwdt_set_heartbeat(new_timeout))
 178                         return -EINVAL;
 179                 advwdt_ping();
 180                 fallthrough;
 181         case WDIOC_GETTIMEOUT:
 182                 return put_user(timeout, p);
 183         default:
 184                 return -ENOTTY;
 185         }
 186         return 0;
 187 }
 188
 189 static int advwdt_open(struct inode *inode, struct file *file)
 190 {
 191         if (test_and_set_bit(0, &advwdt_is_open))
 192                 return -EBUSY;
 193         /*
 194          *      Activate
 195          */
 196
 197         advwdt_ping();
 198         return stream_open(inode, file);
 199 }
 200
 201 static int advwdt_close(struct inode *inode, struct file *file)
 202 {
 203         if (adv_expect_close == 42) {
 204                 advwdt_disable();
 205         } else {
 206                 pr_crit("Unexpected close, not stopping watchdog!\n");
 207                 advwdt_ping();
 208         }
 209         clear_bit(0, &advwdt_is_open);
 210         adv_expect_close = 0;
 211         return 0;
 212 }
 213
 214 /*
 215  *      Kernel Interfaces
 216  */
 217
 218 static const struct file_operations advwdt_fops = {
 219         .owner          = THIS_MODULE,
 220         .llseek         = no_llseek,
 221         .write          = advwdt_write,
 222         .unlocked_ioctl = advwdt_ioctl,
 223         .compat_ioctl   = compat_ptr_ioctl,
 224         .open           = advwdt_open,
 225         .release        = advwdt_close,
 226 };
 227
 228 static struct miscdevice advwdt_miscdev = {
 229         .minor  = WATCHDOG_MINOR,
 230         .name   = "watchdog",
 231         .fops   = &advwdt_fops,
 232 };
 233
 234 /*
 235  *      Init & exit routines
 236  */
 237
 238 static int __init advwdt_probe(struct platform_device *dev)
 239 {
 240         int ret;
 241
 242         if (wdt_stop != wdt_start) {
 243                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 244                         pr_err("I/O address 0x%04x already in use\n",
 245                                wdt_stop);
 246                         ret = -EIO;
 247                         goto out;
 248                 }
 249         }
 250
 251         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 252                 pr_err("I/O address 0x%04x already in use\n", wdt_start);
 253                 ret = -EIO;
 254                 goto unreg_stop;
 255         }
 256
 257         /* Check that the heartbeat value is within it's range ;
 258          * if not reset to the default */
 259         if (advwdt_set_heartbeat(timeout)) {
 260                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 261                 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
 262         }
 263
 264         ret = misc_register(&advwdt_miscdev);
 265         if (ret != 0) {
 266                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 267                        WATCHDOG_MINOR, ret);
 268                 goto unreg_regions;
 269         }
 270         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 271                 timeout, nowayout);
 272 out:
 273         return ret;
 274 unreg_regions:
 275         release_region(wdt_start, 1);
 276 unreg_stop:
 277         if (wdt_stop != wdt_start)
 278                 release_region(wdt_stop, 1);
 279         goto out;
 280 }
 281
 282 static void advwdt_remove(struct platform_device *dev)
 283 {
 284         misc_deregister(&advwdt_miscdev);
 285         release_region(wdt_start, 1);
 286         if (wdt_stop != wdt_start)
 287                 release_region(wdt_stop, 1);
 288 }
 289
 290 static void advwdt_shutdown(struct platform_device *dev)
 291 {
 292         /* Turn the WDT off if we have a soft shutdown */
 293         advwdt_disable();
 294 }
 295
 296 static struct platform_driver advwdt_driver = {
 297         .remove_new     = advwdt_remove,
 298         .shutdown       = advwdt_shutdown,
 299         .driver         = {
 300                 .name   = DRV_NAME,
 301         },
 302 };
 303
 304 static int __init advwdt_init(void)
 305 {
 306         int err;
 307
 308         pr_info("WDT driver for Advantech single board computer initialising\n");
 309
 310         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
 311                                                                 -1, NULL, 0);
 312         if (IS_ERR(advwdt_platform_device))
 313                 return PTR_ERR(advwdt_platform_device);
 314
 315         err = platform_driver_probe(&advwdt_driver, advwdt_probe);
 316         if (err)
 317                 goto unreg_platform_device;
 318
 319         return 0;
 320
 321 unreg_platform_device:
 322         platform_device_unregister(advwdt_platform_device);
 323         return err;
 324 }
 325
 326 static void __exit advwdt_exit(void)
 327 {
 328         platform_device_unregister(advwdt_platform_device);
 329         platform_driver_unregister(&advwdt_driver);
 330         pr_info("Watchdog Module Unloaded\n");
 331 }
 332
 333 module_init(advwdt_init);
 334 module_exit(advwdt_exit);
 335
 336 MODULE_LICENSE("GPL");
 337 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 338 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");