// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  ISA Plug & Play support
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/module.h>
#include <linux/isapnp.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/uaccess.h>

extern struct pnp_protocol isapnp_protocol;

static struct proc_dir_entry *isapnp_proc_bus_dir = NULL;

static loff_t isapnp_proc_bus_lseek(struct file *file, loff_t off, int whence)
{
        return fixed_size_llseek(file, off, whence, 256);
}

static ssize_t isapnp_proc_bus_read(struct file *file, char __user * buf,
                                    size_t nbytes, loff_t * ppos)
{
        struct pnp_dev *dev = pde_data(file_inode(file));
        int pos = *ppos;
        int cnt, size = 256;

        if (pos >= size)
                return 0;
        if (nbytes >= size)
                nbytes = size;
        if (pos + nbytes > size)
                nbytes = size - pos;
        cnt = nbytes;

        if (!access_ok(buf, cnt))
                return -EINVAL;

        isapnp_cfg_begin(dev->card->number, dev->number);
        for (; pos < 256 && cnt > 0; pos++, buf++, cnt--) {
                unsigned char val;
                val = isapnp_read_byte(pos);
                __put_user(val, buf);
        }
        isapnp_cfg_end();

        *ppos = pos;
        return nbytes;
}

static const struct proc_ops isapnp_proc_bus_proc_ops = {
        .proc_lseek     = isapnp_proc_bus_lseek,
        .proc_read      = isapnp_proc_bus_read,
};

static int isapnp_proc_attach_device(struct pnp_dev *dev)
{
        struct pnp_card *bus = dev->card;
        char name[16];

        if (!bus->procdir) {
                sprintf(name, "%02x", bus->number);
                bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
                if (!bus->procdir)
                        return -ENOMEM;
        }
        sprintf(name, "%02x", dev->number);
        dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
                                            &isapnp_proc_bus_proc_ops, dev);
        if (!dev->procent)
                return -ENOMEM;
        proc_set_size(dev->procent, 256);
        return 0;
}

int __init isapnp_proc_init(void)
{
        struct pnp_dev *dev;

        isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
        protocol_for_each_dev(&isapnp_protocol, dev) {
                isapnp_proc_attach_device(dev);
        }
        return 0;
}