// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      uvc_debugfs.c --  USB Video Class driver - Debugging support
 *
 *      Copyright (C) 2011
 *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/usb.h>

#include "uvcvideo.h"

/* -----------------------------------------------------------------------------
 * Statistics
 */

#define UVC_DEBUGFS_BUF_SIZE    1024

struct uvc_debugfs_buffer {
        size_t count;
        char data[UVC_DEBUGFS_BUF_SIZE];
};

static int uvc_debugfs_stats_open(struct inode *inode, struct file *file)
{
        struct uvc_streaming *stream = inode->i_private;
        struct uvc_debugfs_buffer *buf;

        buf = kmalloc_obj(*buf);
        if (buf == NULL)
                return -ENOMEM;

        buf->count = uvc_video_stats_dump(stream, buf->data, sizeof(buf->data));

        file->private_data = buf;
        return 0;
}

static ssize_t uvc_debugfs_stats_read(struct file *file, char __user *user_buf,
                                      size_t nbytes, loff_t *ppos)
{
        struct uvc_debugfs_buffer *buf = file->private_data;

        return simple_read_from_buffer(user_buf, nbytes, ppos, buf->data,
                                       buf->count);
}

static int uvc_debugfs_stats_release(struct inode *inode, struct file *file)
{
        kfree(file->private_data);
        file->private_data = NULL;

        return 0;
}

static const struct file_operations uvc_debugfs_stats_fops = {
        .owner = THIS_MODULE,
        .open = uvc_debugfs_stats_open,
        .read = uvc_debugfs_stats_read,
        .release = uvc_debugfs_stats_release,
};

/* -----------------------------------------------------------------------------
 * Global and stream initialization/cleanup
 */

static struct dentry *uvc_debugfs_root_dir;

void uvc_debugfs_init_stream(struct uvc_streaming *stream)
{
        struct usb_device *udev = stream->dev->udev;
        char dir_name[33];

        if (uvc_debugfs_root_dir == NULL)
                return;

        snprintf(dir_name, sizeof(dir_name), "%u-%u-%u", udev->bus->busnum,
                 udev->devnum, stream->intfnum);

        stream->debugfs_dir = debugfs_create_dir(dir_name,
                                                 uvc_debugfs_root_dir);

        debugfs_create_file("stats", 0444, stream->debugfs_dir, stream,
                            &uvc_debugfs_stats_fops);
}

void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
{
        debugfs_remove_recursive(stream->debugfs_dir);
        stream->debugfs_dir = NULL;
}

void uvc_debugfs_init(void)
{
        uvc_debugfs_root_dir = debugfs_create_dir("uvcvideo", usb_debug_root);
}

void uvc_debugfs_cleanup(void)
{
        debugfs_remove_recursive(uvc_debugfs_root_dir);
}