// SPDX-License-Identifier: GPL-2.0-or-later
/* 
 *    EISA "eeprom" support routines
 *
 *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <asm/eisa_eeprom.h>

static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin)
{
        return fixed_size_llseek(file, offset, origin, HPEE_MAX_LENGTH);
}

static ssize_t eisa_eeprom_read(struct file * file,
                              char __user *buf, size_t count, loff_t *ppos )
{
        unsigned char *tmp;
        ssize_t ret;
        int i;
        
        if (*ppos < 0 || *ppos >= HPEE_MAX_LENGTH)
                return 0;
        
        count = *ppos + count < HPEE_MAX_LENGTH ? count : HPEE_MAX_LENGTH - *ppos;
        tmp = kmalloc(count, GFP_KERNEL);
        if (tmp) {
                for (i = 0; i < count; i++)
                        tmp[i] = readb(eisa_eeprom_addr+(*ppos)++);

                if (copy_to_user (buf, tmp, count))
                        ret = -EFAULT;
                else
                        ret = count;
                kfree (tmp);
        } else
                ret = -ENOMEM;
        
        return ret;
}

static int eisa_eeprom_open(struct inode *inode, struct file *file)
{
        if (file->f_mode & FMODE_WRITE)
                return -EINVAL;
   
        return 0;
}

static int eisa_eeprom_release(struct inode *inode, struct file *file)
{
        return 0;
}

/*
 *      The various file operations we support.
 */
static const struct file_operations eisa_eeprom_fops = {
        .owner =        THIS_MODULE,
        .llseek =       eisa_eeprom_llseek,
        .read =         eisa_eeprom_read,
        .open =         eisa_eeprom_open,
        .release =      eisa_eeprom_release,
};

static struct miscdevice eisa_eeprom_dev = {
        EISA_EEPROM_MINOR,
        "eisa_eeprom",
        &eisa_eeprom_fops
};

static int __init eisa_eeprom_init(void)
{
        int retval;

        if (!eisa_eeprom_addr)
                return -ENODEV;

        retval = misc_register(&eisa_eeprom_dev);
        if (retval < 0) {
                printk(KERN_ERR "EISA EEPROM: cannot register misc device.\n");
                return retval;
        }

        printk(KERN_INFO "EISA EEPROM at 0x%px\n", eisa_eeprom_addr);
        return 0;
}

MODULE_LICENSE("GPL");

module_init(eisa_eeprom_init);