LXR linux/drivers/media/usb/uvc/uvc

   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