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
18static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin)
19{
20	return fixed_size_llseek(file, offset, origin, HPEE_MAX_LENGTH);
21}
22
23static ssize_t eisa_eeprom_read(struct file * file,
24			      char __user *buf, size_t count, loff_t *ppos )
25{
26	unsigned char *tmp;
27	ssize_t ret;
28	int i;
29	
30	if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
31		return 0;
32	
33	count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;
34	tmp = kmalloc(count, GFP_KERNEL);
35	if (tmp) {
36		for (i = 0; i < count; i++)
37			tmp[i] = readb(eisa_eeprom_addr+(*ppos)++);
38
39		if (copy_to_user (buf, tmp, count))
40			ret = -EFAULT;
41		else
42			ret = count;
43		kfree (tmp);
44	} else
45		ret = -ENOMEM;
46	
47	return ret;
48}
49
50static int eisa_eeprom_open(struct inode *inode, struct file *file)
51{
52	if (file->f_mode & FMODE_WRITE)
53		return -EINVAL;
54   
55	return 0;
56}
57
58static int eisa_eeprom_release(struct inode *inode, struct file *file)
59{
60	return 0;
61}
62
63/*
64 *	The various file operations we support.
65 */
66static const struct file_operations eisa_eeprom_fops = {
67	.owner =	THIS_MODULE,
68	.llseek =	eisa_eeprom_llseek,
69	.read =		eisa_eeprom_read,
70	.open =		eisa_eeprom_open,
71	.release =	eisa_eeprom_release,
72};
73
74static struct miscdevice eisa_eeprom_dev = {
75	EISA_EEPROM_MINOR,
76	"eisa_eeprom",
77	&eisa_eeprom_fops
78};
79
80static int __init eisa_eeprom_init(void)
81{
82	int retval;
83
84	if (!eisa_eeprom_addr)
85		return -ENODEV;
86
87	retval = misc_register(&eisa_eeprom_dev);
88	if (retval < 0) {
89		printk(KERN_ERR "EISA EEPROM: cannot register misc device.\n");
90		return retval;
91	}
92
93	printk(KERN_INFO "EISA EEPROM at 0x%px\n", eisa_eeprom_addr);
94	return 0;
95}
96
97MODULE_LICENSE("GPL");
98
99module_init(eisa_eeprom_init);