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 
eisa_eeprom_llseek(struct file * file,loff_t offset,int origin)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 
eisa_eeprom_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)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 
eisa_eeprom_open(struct inode * inode,struct file * file)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 
eisa_eeprom_release(struct inode * inode,struct file * file)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 
eisa_eeprom_init(void)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);
102