drivers/parisc/eisa_eeprom.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *    EISA "eeprom" support routines
0004  *
0005  *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
0006  */
0007
0008 #include <linux/module.h>
0009 #include <linux/init.h>
0010 #include <linux/kernel.h>
0011 #include <linux/miscdevice.h>
0012 #include <linux/slab.h>
0013 #include <linux/fs.h>
0014 #include <asm/io.h>
0015 #include <linux/uaccess.h>
0016 #include <asm/eisa_eeprom.h>
0017
0018 #define     EISA_EEPROM_MINOR 241
0019
0020 static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin)
0021 {
0022     return fixed_size_llseek(file, offset, origin, HPEE_MAX_LENGTH);
0023 }
0024
0025 static ssize_t eisa_eeprom_read(struct file * file,
0026                   char __user *buf, size_t count, loff_t *ppos )
0027 {
0028     unsigned char *tmp;
0029     ssize_t ret;
0030     int i;
0031
0032     if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
0033         return 0;
0034
0035     count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;
0036     tmp = kmalloc(count, GFP_KERNEL);
0037     if (tmp) {
0038         for (i = 0; i < count; i++)
0039             tmp[i] = readb(eisa_eeprom_addr+(*ppos)++);
0040
0041         if (copy_to_user (buf, tmp, count))
0042             ret = -EFAULT;
0043         else
0044             ret = count;
0045         kfree (tmp);
0046     } else
0047         ret = -ENOMEM;
0048
0049     return ret;
0050 }
0051
0052 static int eisa_eeprom_open(struct inode *inode, struct file *file)
0053 {
0054     if (file->f_mode & FMODE_WRITE)
0055         return -EINVAL;
0056
0057     return 0;
0058 }
0059
0060 static int eisa_eeprom_release(struct inode *inode, struct file *file)
0061 {
0062     return 0;
0063 }
0064
0065 /*
0066  *  The various file operations we support.
0067  */
0068 static const struct file_operations eisa_eeprom_fops = {
0069     .owner =    THIS_MODULE,
0070     .llseek =   eisa_eeprom_llseek,
0071     .read =     eisa_eeprom_read,
0072     .open =     eisa_eeprom_open,
0073     .release =  eisa_eeprom_release,
0074 };
0075
0076 static struct miscdevice eisa_eeprom_dev = {
0077     EISA_EEPROM_MINOR,
0078     "eisa_eeprom",
0079     &eisa_eeprom_fops
0080 };
0081
0082 static int __init eisa_eeprom_init(void)
0083 {
0084     int retval;
0085
0086     if (!eisa_eeprom_addr)
0087         return -ENODEV;
0088
0089     retval = misc_register(&eisa_eeprom_dev);
0090     if (retval < 0) {
0091         printk(KERN_ERR "EISA EEPROM: cannot register misc device.\n");
0092         return retval;
0093     }
0094
0095     printk(KERN_INFO "EISA EEPROM at 0x%px\n", eisa_eeprom_addr);
0096     return 0;
0097 }
0098
0099 MODULE_LICENSE("GPL");
0100
0101 module_init(eisa_eeprom_init);