drivers/watchdog/mixcomwd.c

   1 /*
   2  * MixCom Watchdog: A Simple Hardware Watchdog Device
   3  * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis
   4  *
   5  * Author: Gergely Madarasz <gorgo@itc.hu>
   6  *
   7  * Copyright (c) 1999 ITConsult-Pro Co. <info@itc.hu>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  *
  14  * Version 0.1 (99/04/15):
  15  *              - first version
  16  *
  17  * Version 0.2 (99/06/16):
  18  *              - added kernel timer watchdog ping after close
  19  *                since the hardware does not support watchdog shutdown
  20  *
  21  * Version 0.3 (99/06/21):
  22  *              - added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls
  23  *
  24  * Version 0.3.1 (99/06/22):
  25  *              - allow module removal while internal timer is active,
  26  *                print warning about probable reset
  27  *
  28  * Version 0.4 (99/11/15):
  29  *              - support for one more type board
  30  *
  31  * Version 0.5 (2001/12/14) Matt Domsch <Matt_Domsch@dell.com>
  32  *              - added nowayout module option to override
  33  *                CONFIG_WATCHDOG_NOWAYOUT
  34  *
  35  * Version 0.6 (2002/04/12): Rob Radez <rob@osinvestor.com>
  36  *              - make mixcomwd_opened unsigned,
  37  *                removed lock_kernel/unlock_kernel from mixcomwd_release,
  38  *                modified ioctl a bit to conform to API
  39  *
  40  */
  41
  42 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  43
  44 #define VERSION "0.6"
  45 #define WATCHDOG_NAME "mixcomwd"
  46
  47 #include <linux/module.h>
  48 #include <linux/moduleparam.h>
  49 #include <linux/types.h>
  50 #include <linux/miscdevice.h>
  51 #include <linux/ioport.h>
  52 #include <linux/watchdog.h>
  53 #include <linux/fs.h>
  54 #include <linux/reboot.h>
  55 #include <linux/init.h>
  56 #include <linux/jiffies.h>
  57 #include <linux/timer.h>
  58 #include <linux/uaccess.h>
  59 #include <linux/io.h>
  60
  61 /*
  62  * We have two types of cards that can be probed:
  63  * 1) The Mixcom cards: these cards can be found at addresses
  64  *    0x180, 0x280, 0x380 with an additional offset of 0xc10.
  65  *    (Or 0xd90, 0xe90, 0xf90).
  66  * 2) The FlashCOM cards: these cards can be set up at
  67  *    0x300 -> 0x378, in 0x8 jumps with an offset of 0x04.
  68  *    (Or 0x304 -> 0x37c in 0x8 jumps).
  69  *    Each card has it's own ID.
  70  */
  71 #define MIXCOM_ID 0x11
  72 #define FLASHCOM_ID 0x18
  73 static struct {
  74         int ioport;
  75         int id;
  76 } mixcomwd_io_info[] = {
  77         /* The Mixcom cards */
  78         {0x0d90, MIXCOM_ID},
  79         {0x0e90, MIXCOM_ID},
  80         {0x0f90, MIXCOM_ID},
  81         /* The FlashCOM cards */
  82         {0x0304, FLASHCOM_ID},
  83         {0x030c, FLASHCOM_ID},
  84         {0x0314, FLASHCOM_ID},
  85         {0x031c, FLASHCOM_ID},
  86         {0x0324, FLASHCOM_ID},
  87         {0x032c, FLASHCOM_ID},
  88         {0x0334, FLASHCOM_ID},
  89         {0x033c, FLASHCOM_ID},
  90         {0x0344, FLASHCOM_ID},
  91         {0x034c, FLASHCOM_ID},
  92         {0x0354, FLASHCOM_ID},
  93         {0x035c, FLASHCOM_ID},
  94         {0x0364, FLASHCOM_ID},
  95         {0x036c, FLASHCOM_ID},
  96         {0x0374, FLASHCOM_ID},
  97         {0x037c, FLASHCOM_ID},
  98         /* The end of the list */
  99         {0x0000, 0},
 100 };
 101
 102 static void mixcomwd_timerfun(unsigned long d);
 103
 104 static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
 105
 106 static int watchdog_port;
 107 static int mixcomwd_timer_alive;
 108 static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun);
 109 static char expect_close;
 110
 111 static bool nowayout = WATCHDOG_NOWAYOUT;
 112 module_param(nowayout, bool, 0);
 113 MODULE_PARM_DESC(nowayout,
 114                 "Watchdog cannot be stopped once started (default="
 115                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 116
 117 static void mixcomwd_ping(void)
 118 {
 119         outb_p(55, watchdog_port);
 120         return;
 121 }
 122
 123 static void mixcomwd_timerfun(unsigned long d)
 124 {
 125         mixcomwd_ping();
 126         mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
 127 }
 128
 129 /*
 130  *      Allow only one person to hold it open
 131  */
 132
 133 static int mixcomwd_open(struct inode *inode, struct file *file)
 134 {
 135         if (test_and_set_bit(0, &mixcomwd_opened))
 136                 return -EBUSY;
 137
 138         mixcomwd_ping();
 139
 140         if (nowayout)
 141                 /*
 142                  * fops_get() code via open() has already done
 143                  * a try_module_get() so it is safe to do the
 144                  * __module_get().
 145                  */
 146                 __module_get(THIS_MODULE);
 147         else {
 148                 if (mixcomwd_timer_alive) {
 149                         del_timer(&mixcomwd_timer);
 150                         mixcomwd_timer_alive = 0;
 151                 }
 152         }
 153         return nonseekable_open(inode, file);
 154 }
 155
 156 static int mixcomwd_release(struct inode *inode, struct file *file)
 157 {
 158         if (expect_close == 42) {
 159                 if (mixcomwd_timer_alive) {
 160                         pr_err("release called while internal timer alive\n");
 161                         return -EBUSY;
 162                 }
 163                 mixcomwd_timer_alive = 1;
 164                 mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
 165         } else
 166                 pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
 167
 168         clear_bit(0, &mixcomwd_opened);
 169         expect_close = 0;
 170         return 0;
 171 }
 172
 173
 174 static ssize_t mixcomwd_write(struct file *file, const char __user *data,
 175                                                 size_t len, loff_t *ppos)
 176 {
 177         if (len) {
 178                 if (!nowayout) {
 179                         size_t i;
 180
 181                         /* In case it was set long ago */
 182                         expect_close = 0;
 183
 184                         for (i = 0; i != len; i++) {
 185                                 char c;
 186                                 if (get_user(c, data + i))
 187                                         return -EFAULT;
 188                                 if (c == 'V')
 189                                         expect_close = 42;
 190                         }
 191                 }
 192                 mixcomwd_ping();
 193         }
 194         return len;
 195 }
 196
 197 static long mixcomwd_ioctl(struct file *file,
 198                                 unsigned int cmd, unsigned long arg)
 199 {
 200         void __user *argp = (void __user *)arg;
 201         int __user *p = argp;
 202         int status;
 203         static const struct watchdog_info ident = {
 204                 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 205                 .firmware_version = 1,
 206                 .identity = "MixCOM watchdog",
 207         };
 208
 209         switch (cmd) {
 210         case WDIOC_GETSUPPORT:
 211                 if (copy_to_user(argp, &ident, sizeof(ident)))
 212                         return -EFAULT;
 213                 break;
 214         case WDIOC_GETSTATUS:
 215                 status = mixcomwd_opened;
 216                 if (!nowayout)
 217                         status |= mixcomwd_timer_alive;
 218                 return put_user(status, p);
 219         case WDIOC_GETBOOTSTATUS:
 220                 return put_user(0, p);
 221         case WDIOC_KEEPALIVE:
 222                 mixcomwd_ping();
 223                 break;
 224         default:
 225                 return -ENOTTY;
 226         }
 227         return 0;
 228 }
 229
 230 static const struct file_operations mixcomwd_fops = {
 231         .owner          = THIS_MODULE,
 232         .llseek         = no_llseek,
 233         .write          = mixcomwd_write,
 234         .unlocked_ioctl = mixcomwd_ioctl,
 235         .open           = mixcomwd_open,
 236         .release        = mixcomwd_release,
 237 };
 238
 239 static struct miscdevice mixcomwd_miscdev = {
 240         .minor  = WATCHDOG_MINOR,
 241         .name   = "watchdog",
 242         .fops   = &mixcomwd_fops,
 243 };
 244
 245 static int __init checkcard(int port, int card_id)
 246 {
 247         int id;
 248
 249         if (!request_region(port, 1, "MixCOM watchdog"))
 250                 return 0;
 251
 252         id = inb_p(port);
 253         if (card_id == MIXCOM_ID)
 254                 id &= 0x3f;
 255
 256         if (id != card_id) {
 257                 release_region(port, 1);
 258                 return 0;
 259         }
 260         return 1;
 261 }
 262
 263 static int __init mixcomwd_init(void)
 264 {
 265         int i, ret, found = 0;
 266
 267         for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {
 268                 if (checkcard(mixcomwd_io_info[i].ioport,
 269                               mixcomwd_io_info[i].id)) {
 270                         found = 1;
 271                         watchdog_port = mixcomwd_io_info[i].ioport;
 272                 }
 273         }
 274
 275         if (!found) {
 276                 pr_err("No card detected, or port not available\n");
 277                 return -ENODEV;
 278         }
 279
 280         ret = misc_register(&mixcomwd_miscdev);
 281         if (ret) {
 282                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 283                        WATCHDOG_MINOR, ret);
 284                 goto error_misc_register_watchdog;
 285         }
 286
 287         pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",
 288                 VERSION, watchdog_port);
 289
 290         return 0;
 291
 292 error_misc_register_watchdog:
 293         release_region(watchdog_port, 1);
 294         watchdog_port = 0x0000;
 295         return ret;
 296 }
 297
 298 static void __exit mixcomwd_exit(void)
 299 {
 300         if (!nowayout) {
 301                 if (mixcomwd_timer_alive) {
 302                         pr_warn("I quit now, hardware will probably reboot!\n");
 303                         del_timer_sync(&mixcomwd_timer);
 304                         mixcomwd_timer_alive = 0;
 305                 }
 306         }
 307         misc_deregister(&mixcomwd_miscdev);
 308         release_region(watchdog_port, 1);
 309 }
 310
 311 module_init(mixcomwd_init);
 312 module_exit(mixcomwd_exit);
 313
 314 MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
 315 MODULE_DESCRIPTION("MixCom Watchdog driver");
 316 MODULE_VERSION(VERSION);
 317 MODULE_LICENSE("GPL");