drivers/parisc/eisa_eeprom.c

   1 /*
   2  *    EISA "eeprom" support routines
   3  *
   4  *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
   5  *
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2 of the License, or
  10  *    (at your option) any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/slab.h>
  27 #include <linux/fs.h>
  28 #include <asm/io.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/eisa_eeprom.h>
  31
  32 #define         EISA_EEPROM_MINOR 241
  33
  34 static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin )
  35 {
  36         switch (origin) {
  37           case 0:
  38                 /* nothing to do */
  39                 break;
  40           case 1:
  41                 offset += file->f_pos;
  42                 break;
  43           case 2:
  44                 offset += HPEE_MAX_LENGTH;
  45                 break;
  46         }
  47         return (offset >= 0 && offset < HPEE_MAX_LENGTH) ? (file->f_pos = offset) : -EINVAL;
  48 }
  49
  50 static ssize_t eisa_eeprom_read(struct file * file,
  51                               char __user *buf, size_t count, loff_t *ppos )
  52 {
  53         unsigned char *tmp;
  54         ssize_t ret;
  55         int i;
  56
  57         if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
  58                 return 0;
  59
  60         count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;
  61         tmp = kmalloc(count, GFP_KERNEL);
  62         if (tmp) {
  63                 for (i = 0; i < count; i++)
  64                         tmp[i] = readb(eisa_eeprom_addr+(*ppos)++);
  65
  66                 if (copy_to_user (buf, tmp, count))
  67                         ret = -EFAULT;
  68                 else
  69                         ret = count;
  70                 kfree (tmp);
  71         } else
  72                 ret = -ENOMEM;
  73
  74         return ret;
  75 }
  76
  77 static int eisa_eeprom_open(struct inode *inode, struct file *file)
  78 {
  79         if (file->f_mode & FMODE_WRITE)
  80                 return -EINVAL;
  81
  82         return 0;
  83 }
  84
  85 static int eisa_eeprom_release(struct inode *inode, struct file *file)
  86 {
  87         return 0;
  88 }
  89
  90 /*
  91  *      The various file operations we support.
  92  */
  93 static const struct file_operations eisa_eeprom_fops = {
  94         .owner =        THIS_MODULE,
  95         .llseek =       eisa_eeprom_llseek,
  96         .read =         eisa_eeprom_read,
  97         .open =         eisa_eeprom_open,
  98         .release =      eisa_eeprom_release,
  99 };
 100
 101 static struct miscdevice eisa_eeprom_dev = {
 102         EISA_EEPROM_MINOR,
 103         "eisa_eeprom",
 104         &eisa_eeprom_fops
 105 };
 106
 107 static int __init eisa_eeprom_init(void)
 108 {
 109         int retval;
 110
 111         if (!eisa_eeprom_addr)
 112                 return -ENODEV;
 113
 114         retval = misc_register(&eisa_eeprom_dev);
 115         if (retval < 0) {
 116                 printk(KERN_ERR "EISA EEPROM: cannot register misc device.\n");
 117                 return retval;
 118         }
 119
 120         printk(KERN_INFO "EISA EEPROM at 0x%p\n", eisa_eeprom_addr);
 121         return 0;
 122 }
 123
 124 MODULE_LICENSE("GPL");
 125
 126 module_init(eisa_eeprom_init);