drivers/parisc/eisa_eeprom.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *    EISA "eeprom" support routines
   4  *
   5  *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/miscdevice.h>
  12 #include <linux/slab.h>
  13 #include <linux/fs.h>
  14 #include <asm/io.h>
  15 #include <linux/uaccess.h>
  16 #include <asm/eisa_eeprom.h>
  17
  18 #define         EISA_EEPROM_MINOR 241
  19
  20 static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin)
  21 {
  22         return fixed_size_llseek(file, offset, origin, HPEE_MAX_LENGTH);
  23 }
  24
  25 static ssize_t eisa_eeprom_read(struct file * file,
  26                               char __user *buf, size_t count, loff_t *ppos )
  27 {
  28         unsigned char *tmp;
  29         ssize_t ret;
  30         int i;
  31
  32         if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
  33                 return 0;
  34
  35         count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;
  36         tmp = kmalloc(count, GFP_KERNEL);
  37         if (tmp) {
  38                 for (i = 0; i < count; i++)
  39                         tmp[i] = readb(eisa_eeprom_addr+(*ppos)++);
  40
  41                 if (copy_to_user (buf, tmp, count))
  42                         ret = -EFAULT;
  43                 else
  44                         ret = count;
  45                 kfree (tmp);
  46         } else
  47                 ret = -ENOMEM;
  48
  49         return ret;
  50 }
  51
  52 static int eisa_eeprom_open(struct inode *inode, struct file *file)
  53 {
  54         if (file->f_mode & FMODE_WRITE)
  55                 return -EINVAL;
  56
  57         return 0;
  58 }
  59
  60 static int eisa_eeprom_release(struct inode *inode, struct file *file)
  61 {
  62         return 0;
  63 }
  64
  65 /*
  66  *      The various file operations we support.
  67  */
  68 static const struct file_operations eisa_eeprom_fops = {
  69         .owner =        THIS_MODULE,
  70         .llseek =       eisa_eeprom_llseek,
  71         .read =         eisa_eeprom_read,
  72         .open =         eisa_eeprom_open,
  73         .release =      eisa_eeprom_release,
  74 };
  75
  76 static struct miscdevice eisa_eeprom_dev = {
  77         EISA_EEPROM_MINOR,
  78         "eisa_eeprom",
  79         &eisa_eeprom_fops
  80 };
  81
  82 static int __init eisa_eeprom_init(void)
  83 {
  84         int retval;
  85
  86         if (!eisa_eeprom_addr)
  87                 return -ENODEV;
  88
  89         retval = misc_register(&eisa_eeprom_dev);
  90         if (retval < 0) {
  91                 printk(KERN_ERR "EISA EEPROM: cannot register misc device.\n");
  92                 return retval;
  93         }
  94
  95         printk(KERN_INFO "EISA EEPROM at 0x%px\n", eisa_eeprom_addr);
  96         return 0;
  97 }
  98
  99 MODULE_LICENSE("GPL");
 100
 101 module_init(eisa_eeprom_init);