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