drivers/char/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 CONFIG_WATCHDOG_NOWAYOUT
  33  *
  34  */
  35
  36 #define VERSION "0.5"
  37
  38 #include <linux/module.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/config.h>
  41 #include <linux/types.h>
  42 #include <linux/miscdevice.h>
  43 #include <linux/ioport.h>
  44 #include <linux/watchdog.h>
  45 #include <linux/fs.h>
  46 #include <linux/reboot.h>
  47 #include <linux/init.h>
  48 #include <linux/jiffies.h>
  49 #include <linux/timer.h>
  50 #include <asm/uaccess.h>
  51 #include <asm/io.h>
  52
  53 static int mixcomwd_ioports[] = { 0x180, 0x280, 0x380, 0x000 };
  54
  55 #define MIXCOM_WATCHDOG_OFFSET 0xc10
  56 #define MIXCOM_ID 0x11
  57 #define FLASHCOM_WATCHDOG_OFFSET 0x4
  58 #define FLASHCOM_ID 0x18
  59
  60 static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
  61
  62 static int watchdog_port;
  63 static int mixcomwd_timer_alive;
  64 static DEFINE_TIMER(mixcomwd_timer, NULL, 0, 0);
  65 static char expect_close;
  66
  67 static int nowayout = WATCHDOG_NOWAYOUT;
  68 module_param(nowayout, int, 0);
  69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  70
  71 static void mixcomwd_ping(void)
  72 {
  73         outb_p(55,watchdog_port);
  74         return;
  75 }
  76
  77 static void mixcomwd_timerfun(unsigned long d)
  78 {
  79         mixcomwd_ping();
  80
  81         mod_timer(&mixcomwd_timer,jiffies+ 5*HZ);
  82 }
  83
  84 /*
  85  *      Allow only one person to hold it open
  86  */
  87
  88 static int mixcomwd_open(struct inode *inode, struct file *file)
  89 {
  90         if(test_and_set_bit(0,&mixcomwd_opened)) {
  91                 return -EBUSY;
  92         }
  93         mixcomwd_ping();
  94
  95         if (nowayout) {
  96                 /*
  97                  * fops_get() code via open() has already done
  98                  * a try_module_get() so it is safe to do the
  99                  * __module_get().
 100                  */
 101                 __module_get(THIS_MODULE);
 102         } else {
 103                 if(mixcomwd_timer_alive) {
 104                         del_timer(&mixcomwd_timer);
 105                         mixcomwd_timer_alive=0;
 106                 }
 107         }
 108         return nonseekable_open(inode, file);
 109 }
 110
 111 static int mixcomwd_release(struct inode *inode, struct file *file)
 112 {
 113         if (expect_close == 42) {
 114                 if(mixcomwd_timer_alive) {
 115                         printk(KERN_ERR "mixcomwd: release called while internal timer alive");
 116                         return -EBUSY;
 117                 }
 118                 init_timer(&mixcomwd_timer);
 119                 mixcomwd_timer.expires=jiffies + 5 * HZ;
 120                 mixcomwd_timer.function=mixcomwd_timerfun;
 121                 mixcomwd_timer.data=0;
 122                 mixcomwd_timer_alive=1;
 123                 add_timer(&mixcomwd_timer);
 124         } else {
 125                 printk(KERN_CRIT "mixcomwd: WDT device closed unexpectedly.  WDT will not stop!\n");
 126         }
 127
 128         clear_bit(0,&mixcomwd_opened);
 129         expect_close=0;
 130         return 0;
 131 }
 132
 133
 134 static ssize_t mixcomwd_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
 135 {
 136         if(len)
 137         {
 138                 if (!nowayout) {
 139                         size_t i;
 140
 141                         /* In case it was set long ago */
 142                         expect_close = 0;
 143
 144                         for (i = 0; i != len; i++) {
 145                                 char c;
 146                                 if (get_user(c, data + i))
 147                                         return -EFAULT;
 148                                 if (c == 'V')
 149                                         expect_close = 42;
 150                         }
 151                 }
 152                 mixcomwd_ping();
 153         }
 154         return len;
 155 }
 156
 157 static int mixcomwd_ioctl(struct inode *inode, struct file *file,
 158         unsigned int cmd, unsigned long arg)
 159 {
 160         void __user *argp = (void __user *)arg;
 161         int __user *p = argp;
 162         int status;
 163         static struct watchdog_info ident = {
 164                 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 165                 .firmware_version = 1,
 166                 .identity = "MixCOM watchdog",
 167         };
 168
 169         switch(cmd)
 170         {
 171                 case WDIOC_GETSTATUS:
 172                         status=mixcomwd_opened;
 173                         if (!nowayout) {
 174                                 status|=mixcomwd_timer_alive;
 175                         }
 176                         if (copy_to_user(p, &status, sizeof(int))) {
 177                                 return -EFAULT;
 178                         }
 179                         break;
 180                 case WDIOC_GETSUPPORT:
 181                         if (copy_to_user(argp, &ident, sizeof(ident))) {
 182                                 return -EFAULT;
 183                         }
 184                         break;
 185                 case WDIOC_KEEPALIVE:
 186                         mixcomwd_ping();
 187                         break;
 188                 default:
 189                         return -ENOIOCTLCMD;
 190         }
 191         return 0;
 192 }
 193
 194 static struct file_operations mixcomwd_fops=
 195 {
 196         .owner          = THIS_MODULE,
 197         .llseek         = no_llseek,
 198         .write          = mixcomwd_write,
 199         .ioctl          = mixcomwd_ioctl,
 200         .open           = mixcomwd_open,
 201         .release        = mixcomwd_release,
 202 };
 203
 204 static struct miscdevice mixcomwd_miscdev=
 205 {
 206         .minor  = WATCHDOG_MINOR,
 207         .name   = "watchdog",
 208         .fops   = &mixcomwd_fops,
 209 };
 210
 211 static int __init mixcomwd_checkcard(int port)
 212 {
 213         int id;
 214
 215         port += MIXCOM_WATCHDOG_OFFSET;
 216         if (!request_region(port, 1, "MixCOM watchdog")) {
 217                 return 0;
 218         }
 219
 220         id=inb_p(port) & 0x3f;
 221         if(id!=MIXCOM_ID) {
 222                 release_region(port, 1);
 223                 return 0;
 224         }
 225         return port;
 226 }
 227
 228 static int __init flashcom_checkcard(int port)
 229 {
 230         int id;
 231
 232         port += FLASHCOM_WATCHDOG_OFFSET;
 233         if (!request_region(port, 1, "MixCOM watchdog")) {
 234                 return 0;
 235         }
 236
 237         id=inb_p(port);
 238         if(id!=FLASHCOM_ID) {
 239                 release_region(port, 1);
 240                 return 0;
 241         }
 242         return port;
 243  }
 244
 245 static int __init mixcomwd_init(void)
 246 {
 247         int i;
 248         int ret;
 249         int found=0;
 250
 251         for (i = 0; !found && mixcomwd_ioports[i] != 0; i++) {
 252                 watchdog_port = mixcomwd_checkcard(mixcomwd_ioports[i]);
 253                 if (watchdog_port) {
 254                         found = 1;
 255                 }
 256         }
 257
 258         /* The FlashCOM card can be set up at 0x300 -> 0x378, in 0x8 jumps */
 259         for (i = 0x300; !found && i < 0x380; i+=0x8) {
 260                 watchdog_port = flashcom_checkcard(i);
 261                 if (watchdog_port) {
 262                         found = 1;
 263                 }
 264         }
 265
 266         if (!found) {
 267                 printk("mixcomwd: No card detected, or port not available.\n");
 268                 return -ENODEV;
 269         }
 270
 271         ret = misc_register(&mixcomwd_miscdev);
 272         if (ret)
 273         {
 274                 release_region(watchdog_port, 1);
 275                 return ret;
 276         }
 277
 278         printk(KERN_INFO "MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",VERSION,watchdog_port);
 279
 280         return 0;
 281 }
 282
 283 static void __exit mixcomwd_exit(void)
 284 {
 285         if (!nowayout) {
 286                 if(mixcomwd_timer_alive) {
 287                         printk(KERN_WARNING "mixcomwd: I quit now, hardware will"
 288                                " probably reboot!\n");
 289                         del_timer(&mixcomwd_timer);
 290                         mixcomwd_timer_alive=0;
 291                 }
 292         }
 293         release_region(watchdog_port,1);
 294         misc_deregister(&mixcomwd_miscdev);
 295 }
 296
 297 module_init(mixcomwd_init);
 298 module_exit(mixcomwd_exit);
 299
 300 MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
 301 MODULE_DESCRIPTION("MixCom Watchdog driver");
 302 MODULE_LICENSE("GPL");
 303 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);