1 /*
2  *      uvc_debugfs.c --  USB Video Class driver - Debugging support
3  *
4  *      Copyright (C) 2011
5  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
6  *
7  *      This program is free software; you can redistribute it and/or modify
8  *      it under the terms of the GNU General Public License as published by
9  *      the Free Software Foundation; either version 2 of the License, or
10  *      (at your option) any later version.
11  *
12  */
13 
14 #include <linux/module.h>
15 #include <linux/debugfs.h>
16 #include <linux/slab.h>
17 #include <linux/usb.h>
18 
19 #include "uvcvideo.h"
20 
21 /* -----------------------------------------------------------------------------
22  * Statistics
23  */
24 
25 #define UVC_DEBUGFS_BUF_SIZE	1024
26 
27 struct uvc_debugfs_buffer {
28 	size_t count;
29 	char data[UVC_DEBUGFS_BUF_SIZE];
30 };
31 
32 static int uvc_debugfs_stats_open(struct inode *inode, struct file *file)
33 {
34 	struct uvc_streaming *stream = inode->i_private;
35 	struct uvc_debugfs_buffer *buf;
36 
37 	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
38 	if (buf == NULL)
39 		return -ENOMEM;
40 
41 	buf->count = uvc_video_stats_dump(stream, buf->data, sizeof(buf->data));
42 
43 	file->private_data = buf;
44 	return 0;
45 }
46 
47 static ssize_t uvc_debugfs_stats_read(struct file *file, char __user *user_buf,
48 				      size_t nbytes, loff_t *ppos)
49 {
50 	struct uvc_debugfs_buffer *buf = file->private_data;
51 
52 	return simple_read_from_buffer(user_buf, nbytes, ppos, buf->data,
53 				       buf->count);
54 }
55 
56 static int uvc_debugfs_stats_release(struct inode *inode, struct file *file)
57 {
58 	kfree(file->private_data);
59 	file->private_data = NULL;
60 
61 	return 0;
62 }
63 
64 static const struct file_operations uvc_debugfs_stats_fops = {
65 	.owner = THIS_MODULE,
66 	.open = uvc_debugfs_stats_open,
67 	.llseek = no_llseek,
68 	.read = uvc_debugfs_stats_read,
69 	.release = uvc_debugfs_stats_release,
70 };
71 
72 /* -----------------------------------------------------------------------------
73  * Global and stream initialization/cleanup
74  */
75 
76 static struct dentry *uvc_debugfs_root_dir;
77 
78 void uvc_debugfs_init_stream(struct uvc_streaming *stream)
79 {
80 	struct usb_device *udev = stream->dev->udev;
81 	struct dentry *dent;
82 	char dir_name[32];
83 
84 	if (uvc_debugfs_root_dir == NULL)
85 		return;
86 
87 	sprintf(dir_name, "%u-%u", udev->bus->busnum, udev->devnum);
88 
89 	dent = debugfs_create_dir(dir_name, uvc_debugfs_root_dir);
90 	if (IS_ERR_OR_NULL(dent)) {
91 		uvc_printk(KERN_INFO, "Unable to create debugfs %s "
92 			   "directory.\n", dir_name);
93 		return;
94 	}
95 
96 	stream->debugfs_dir = dent;
97 
98 	dent = debugfs_create_file("stats", 0444, stream->debugfs_dir,
99 				   stream, &uvc_debugfs_stats_fops);
100 	if (IS_ERR_OR_NULL(dent)) {
101 		uvc_printk(KERN_INFO, "Unable to create debugfs stats file.\n");
102 		uvc_debugfs_cleanup_stream(stream);
103 		return;
104 	}
105 }
106 
107 void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
108 {
109 	if (stream->debugfs_dir == NULL)
110 		return;
111 
112 	debugfs_remove_recursive(stream->debugfs_dir);
113 	stream->debugfs_dir = NULL;
114 }
115 
116 void uvc_debugfs_init(void)
117 {
118 	struct dentry *dir;
119 
120 	dir = debugfs_create_dir("uvcvideo", usb_debug_root);
121 	if (IS_ERR_OR_NULL(dir)) {
122 		uvc_printk(KERN_INFO, "Unable to create debugfs directory\n");
123 		return;
124 	}
125 
126 	uvc_debugfs_root_dir = dir;
127 }
128 
129 void uvc_debugfs_cleanup(void)
130 {
131 	if (uvc_debugfs_root_dir != NULL)
132 		debugfs_remove_recursive(uvc_debugfs_root_dir);
133 }
134