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
22 struct uvc_debugfs_buffer {
23 size_t count;
24 char data[UVC_DEBUGFS_BUF_SIZE];
25 };
26
uvc_debugfs_stats_open(struct inode * inode,struct file * file)27 static 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
uvc_debugfs_stats_read(struct file * file,char __user * user_buf,size_t nbytes,loff_t * ppos)42 static 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
uvc_debugfs_stats_release(struct inode * inode,struct file * file)51 static 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
59 static 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
71 static struct dentry *uvc_debugfs_root_dir;
72
uvc_debugfs_init_stream(struct uvc_streaming * stream)73 void uvc_debugfs_init_stream(struct uvc_streaming *stream)
74 {
75 struct usb_device *udev = stream->dev->udev;
76 struct dentry *dent;
77 char dir_name[33];
78
79 if (uvc_debugfs_root_dir == NULL)
80 return;
81
82 snprintf(dir_name, sizeof(dir_name), "%u-%u-%u", udev->bus->busnum,
83 udev->devnum, stream->intfnum);
84
85 dent = debugfs_create_dir(dir_name, uvc_debugfs_root_dir);
86 if (IS_ERR_OR_NULL(dent)) {
87 uvc_printk(KERN_INFO, "Unable to create debugfs %s "
88 "directory.\n", dir_name);
89 return;
90 }
91
92 stream->debugfs_dir = dent;
93
94 dent = debugfs_create_file("stats", 0444, stream->debugfs_dir,
95 stream, &uvc_debugfs_stats_fops);
96 if (IS_ERR_OR_NULL(dent)) {
97 uvc_printk(KERN_INFO, "Unable to create debugfs stats file.\n");
98 uvc_debugfs_cleanup_stream(stream);
99 return;
100 }
101 }
102
uvc_debugfs_cleanup_stream(struct uvc_streaming * stream)103 void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
104 {
105 debugfs_remove_recursive(stream->debugfs_dir);
106 stream->debugfs_dir = NULL;
107 }
108
uvc_debugfs_init(void)109 void uvc_debugfs_init(void)
110 {
111 struct dentry *dir;
112
113 dir = debugfs_create_dir("uvcvideo", usb_debug_root);
114 if (IS_ERR_OR_NULL(dir)) {
115 uvc_printk(KERN_INFO, "Unable to create debugfs directory\n");
116 return;
117 }
118
119 uvc_debugfs_root_dir = dir;
120 }
121
uvc_debugfs_cleanup(void)122 void uvc_debugfs_cleanup(void)
123 {
124 debugfs_remove_recursive(uvc_debugfs_root_dir);
125 }
126