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/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2026-present Eclipse ThreadX contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** USBX Component */
/** */
/** Video Class */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_host_class_video.h"
#include "ux_host_stack.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_host_class_video_entities_parse PORTABLE C */
/* 6.1.12 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parsees all interface descriptors and their video */
/* class specific descriptors. */
/* */
/* The function scans the device configuration descriptor. Once the */
/* interface descriptors of the video instance are found, each video */
/* class descriptors belong to the interface are passed to parse */
/* function for caller one by one to parse. The interface descriptor */
/* is also passed to provide more information. Another pointer to */
/* arguments is also available as parse function parameter for caller */
/* to pass necessary caller specific data to process in parse function.*/
/* */
/* The descriptor parsing can be terminated by returning non-zero */
/* code in parse function. */
/* */
/* INPUT */
/* */
/* video Pointer to video instance */
/* parse_function Parse function for each */
/* video class descriptor */
/* arg Parse function argument */
/* */
/* OUTPUT */
/* */
/* Completion Status */
/* */
/* CALLS */
/* */
/* CALLED BY */
/* */
/* Video Class */
/* Application */
/* */
/**************************************************************************/
UINT _ux_host_class_video_entities_parse(UX_HOST_CLASS_VIDEO *video,
UINT(*parse_function)(VOID *arg,
UCHAR *packed_interface_descriptor,
UCHAR *packed_entity_descriptor),
VOID* arg)
{
UCHAR *descriptor;
UCHAR *interface_descriptor;
UX_INTERFACE *interface_ptr;
ULONG total_descriptor_length;
ULONG descriptor_length;
ULONG descriptor_type;
UINT status;
/* Device state check. */
if (video -> ux_host_class_video_device -> ux_device_state != UX_DEVICE_CONFIGURED)
return(UX_HOST_CLASS_VIDEO_DEVICE_NOT_READY);
/* Get the descriptor to the selected format. */
descriptor = video -> ux_host_class_video_configuration_descriptor;
total_descriptor_length = video -> ux_host_class_video_configuration_descriptor_length;
/* Haven't found interface yet. */
interface_descriptor = UX_NULL;
/* Scan the descriptor for the Video Streaming interface. */
while (total_descriptor_length)
{
/* Gather the length, type and subtype of the descriptor. */
descriptor_length = *descriptor;
descriptor_type = *(descriptor + 1);
/* Make sure this descriptor has at least the minimum length. */
if (descriptor_length < 3)
return(UX_DESCRIPTOR_CORRUPTED);
/* Process relative to descriptor type. */
switch (descriptor_type)
{
case UX_INTERFACE_DESCRIPTOR_ITEM:
/* Haven't found it. */
interface_descriptor = UX_NULL;
/* Ensure we have the correct interface for Video Control/Streaming. */
if (descriptor[5] == UX_HOST_CLASS_VIDEO_CLASS)
{
/* VideoControl Interface. */
if (descriptor[6] == UX_HOST_CLASS_VIDEO_SUBCLASS_CONTROL)
/* Mark we have found it. */
interface_descriptor = descriptor;
else
{
/* VideoStreaming interface, currently only one supported. */
interface_ptr = video -> ux_host_class_video_streaming_interface;
if (descriptor[2] == interface_ptr -> ux_interface_descriptor.bInterfaceNumber)
/* Mark we have found it. */
interface_descriptor = descriptor;
}
}
break;
case UX_HOST_CLASS_VIDEO_CS_INTERFACE:
/* Have we found the video interface yet? */
if (interface_descriptor != UX_NULL)
{
/* Yes, parse the entity descriptor. */
status = parse_function(arg, interface_descriptor, descriptor);
/* Terminate the parsing if status is not 0. */
if (status)
return(UX_SUCCESS);
}
break;
}
/* Verify if the descriptor is still valid. */
if (descriptor_length > total_descriptor_length)
return(UX_DESCRIPTOR_CORRUPTED);
/* Jump to the next descriptor if we have not reached the end. */
descriptor += descriptor_length;
/* And adjust the length left to parse in the descriptor. */
total_descriptor_length -= descriptor_length;
}
/* We get here when all descriptors scanned. */
return(UX_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _uxe_host_class_video_entities_parse PORTABLE C */
/* 6.3.0 */
/* AUTHOR */
/* */
/* Yajun Xia, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function checks errors in video entities parse function call. */
/* */
/* INPUT */
/* */
/* video Pointer to video instance */
/* parse_function Parse function for each */
/* video class descriptor */
/* arg Parse function argument */
/* */
/* OUTPUT */
/* */
/* Completion Status */
/* */
/* CALLS */
/* */
/* _ux_host_class_video_entities_parse Video entities parse */
/* */
/* CALLED BY */
/* */
/* Video Class */
/* Application */
/* */
/**************************************************************************/
UINT _uxe_host_class_video_entities_parse(UX_HOST_CLASS_VIDEO *video,
UINT(*parse_function)(VOID *arg,
UCHAR *packed_interface_descriptor,
UCHAR *packed_entity_descriptor),
VOID* arg)
{
/* Sanity checks. */
if (video == UX_NULL)
return(UX_INVALID_PARAMETER);
/* Call the actual video entities parse function. */
return(_ux_host_class_video_entities_parse(video, parse_function, arg));
}
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