1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *      uvc_debugfs.c --  USB Video Class driver - Debugging support
4 *
5 *      Copyright (C) 2011
6 *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
7 */
8
9#include <linux/module.h>
10#include <linux/debugfs.h>
11#include <linux/slab.h>
12#include <linux/usb.h>
13
14#include "uvcvideo.h"
15
16/* -----------------------------------------------------------------------------
17 * Statistics
18 */
19
20#define UVC_DEBUGFS_BUF_SIZE	1024
21
22struct uvc_debugfs_buffer {
23	size_t count;
24	char data[UVC_DEBUGFS_BUF_SIZE];
25};
26
27static int uvc_debugfs_stats_open(struct inode *inode, struct file *file)
28{
29	struct uvc_streaming *stream = inode->i_private;
30	struct uvc_debugfs_buffer *buf;
31
32	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
33	if (buf == NULL)
34		return -ENOMEM;
35
36	buf->count = uvc_video_stats_dump(stream, buf->data, sizeof(buf->data));
37
38	file->private_data = buf;
39	return 0;
40}
41
42static ssize_t uvc_debugfs_stats_read(struct file *file, char __user *user_buf,
43				      size_t nbytes, loff_t *ppos)
44{
45	struct uvc_debugfs_buffer *buf = file->private_data;
46
47	return simple_read_from_buffer(user_buf, nbytes, ppos, buf->data,
48				       buf->count);
49}
50
51static int uvc_debugfs_stats_release(struct inode *inode, struct file *file)
52{
53	kfree(file->private_data);
54	file->private_data = NULL;
55
56	return 0;
57}
58
59static const struct file_operations uvc_debugfs_stats_fops = {
60	.owner = THIS_MODULE,
61	.open = uvc_debugfs_stats_open,
62	.llseek = no_llseek,
63	.read = uvc_debugfs_stats_read,
64	.release = uvc_debugfs_stats_release,
65};
66
67/* -----------------------------------------------------------------------------
68 * Global and stream initialization/cleanup
69 */
70
71static struct dentry *uvc_debugfs_root_dir;
72
73void uvc_debugfs_init_stream(struct uvc_streaming *stream)
74{
75	struct usb_device *udev = stream->dev->udev;
76	char dir_name[33];
77
78	if (uvc_debugfs_root_dir == NULL)
79		return;
80
81	snprintf(dir_name, sizeof(dir_name), "%u-%u-%u", udev->bus->busnum,
82		 udev->devnum, stream->intfnum);
83
84	stream->debugfs_dir = debugfs_create_dir(dir_name,
85						 uvc_debugfs_root_dir);
86
87	debugfs_create_file("stats", 0444, stream->debugfs_dir, stream,
88			    &uvc_debugfs_stats_fops);
89}
90
91void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
92{
93	debugfs_remove_recursive(stream->debugfs_dir);
94	stream->debugfs_dir = NULL;
95}
96
97void uvc_debugfs_init(void)
98{
99	uvc_debugfs_root_dir = debugfs_create_dir("uvcvideo", usb_debug_root);
100}
101
102void uvc_debugfs_cleanup(void)
103{
104	debugfs_remove_recursive(uvc_debugfs_root_dir);
105}
106