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