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