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