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