uvc_debugfs.c

  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	.read = uvc_debugfs_stats_read,
 63	.release = uvc_debugfs_stats_release,
 64};
 65
 66/* -----------------------------------------------------------------------------
 67 * Global and stream initialization/cleanup
 68 */
 69
 70static struct dentry *uvc_debugfs_root_dir;
 71
 72void uvc_debugfs_init_stream(struct uvc_streaming *stream)
 73{
 74	struct usb_device *udev = stream->dev->udev;
 75	char dir_name[33];
 76
 77	if (uvc_debugfs_root_dir == NULL)
 78		return;
 79
 80	snprintf(dir_name, sizeof(dir_name), "%u-%u-%u", udev->bus->busnum,
 81		 udev->devnum, stream->intfnum);
 82
 83	stream->debugfs_dir = debugfs_create_dir(dir_name,
 84						 uvc_debugfs_root_dir);
 85
 86	debugfs_create_file("stats", 0444, stream->debugfs_dir, stream,
 87			    &uvc_debugfs_stats_fops);
 88}
 89
 90void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
 91{
 92	debugfs_remove_recursive(stream->debugfs_dir);
 93	stream->debugfs_dir = NULL;
 94}
 95
 96void uvc_debugfs_init(void)
 97{
 98	uvc_debugfs_root_dir = debugfs_create_dir("uvcvideo", usb_debug_root);
 99}
100
101void uvc_debugfs_cleanup(void)
102{
103	debugfs_remove_recursive(uvc_debugfs_root_dir);
104}