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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 */
/** */
/** HID Class */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_host_class_hid.h"
#include "ux_host_stack.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_host_class_hid_descriptor_parse PORTABLE C */
/* 6.1.12 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function obtains the HID descriptor and parses it. */
/* */
/* INPUT */
/* */
/* hid Pointer to HID class */
/* */
/* OUTPUT */
/* */
/* Completion Status */
/* */
/* CALLS */
/* */
/* _ux_host_class_hid_report_descriptor_get */
/* Get HID report descriptor */
/* _ux_host_stack_transfer_request Process transfer request */
/* _ux_utility_descriptor_parse Parse descriptor */
/* _ux_utility_memory_allocate Allocate memory block */
/* _ux_utility_memory_free Release memory block */
/* */
/* CALLED BY */
/* */
/* HID Class */
/* */
/**************************************************************************/
UINT _ux_host_class_hid_descriptor_parse(UX_HOST_CLASS_HID *hid)
{
UX_DEVICE *device;
UX_CONFIGURATION *configuration;
UCHAR *descriptor;
UCHAR *start_descriptor;
UX_ENDPOINT *control_endpoint;
UX_TRANSFER *transfer_request;
UX_HID_DESCRIPTOR hid_descriptor;
UX_INTERFACE_DESCRIPTOR interface_descriptor;
UINT status;
ULONG total_configuration_length;
UINT descriptor_length;
UINT descriptor_type;
ULONG current_interface;
/* Get device, current configuration. */
device = hid -> ux_host_class_hid_device;
configuration = device -> ux_device_current_configuration;
total_configuration_length = configuration -> ux_configuration_descriptor.wTotalLength;
/* Check if descriptor is previously saved. */
if (device -> ux_device_packed_configuration != UX_NULL)
{
start_descriptor = device -> ux_device_packed_configuration;
descriptor = start_descriptor;
status = UX_SUCCESS;
}
else
{
/* We need to get the default control endpoint transfer request pointer. */
control_endpoint = &device -> ux_device_control_endpoint;
transfer_request = &control_endpoint -> ux_endpoint_transfer_request;
/* Need to allocate memory for the descriptor. Since we do not know the size of the
descriptor, we first read the first bytes. */
descriptor = _ux_utility_memory_allocate(UX_SAFE_ALIGN, UX_CACHE_SAFE_MEMORY, total_configuration_length);
if (descriptor == UX_NULL)
return(UX_MEMORY_INSUFFICIENT);
/* Memorize the descriptor start address. */
start_descriptor = descriptor;
/* Create a transfer request for the GET_DESCRIPTOR request. */
transfer_request -> ux_transfer_request_data_pointer = descriptor;
transfer_request -> ux_transfer_request_requested_length = total_configuration_length;
transfer_request -> ux_transfer_request_function = UX_GET_DESCRIPTOR;
transfer_request -> ux_transfer_request_type = UX_REQUEST_IN | UX_REQUEST_TYPE_STANDARD | UX_REQUEST_TARGET_DEVICE;
transfer_request -> ux_transfer_request_value = UX_CONFIGURATION_DESCRIPTOR_ITEM << 8;
transfer_request -> ux_transfer_request_index = 0;
/* Send request to HCD layer. */
status = _ux_host_stack_transfer_request(transfer_request);
/* Check descriptor length. */
if (transfer_request -> ux_transfer_request_actual_length != total_configuration_length)
status = UX_DESCRIPTOR_CORRUPTED;
}
/* Reset the current interface to keep compiler warnings happy. */
current_interface = 0;
/* Check for correct transfer and entire descriptor returned. */
if (status == UX_SUCCESS)
{
/* The HID descriptor is embedded within the configuration descriptor. We parse the
entire descriptor to locate the HID portion. */
while (total_configuration_length)
{
/* Gather the length and type of the descriptor. */
descriptor_length = *descriptor;
descriptor_type = *(descriptor + 1);
/* Make sure this descriptor has at least the minimum length. */
if (descriptor_length < 3)
{
/* Error trap. */
_ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_DESCRIPTOR_CORRUPTED);
/* If trace is enabled, insert this event into the trace buffer. */
UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_DESCRIPTOR_CORRUPTED, descriptor, 0, 0, UX_TRACE_ERRORS, 0, 0)
/* Error, release the memory and return an error. */
_ux_utility_memory_free(start_descriptor);
return(UX_DESCRIPTOR_CORRUPTED);
}
/* Check the type for an interface descriptor. */
if (descriptor_type == UX_INTERFACE_DESCRIPTOR_ITEM)
{
/* Parse the interface descriptor and make it machine independent. */
_ux_utility_descriptor_parse(descriptor,
_ux_system_interface_descriptor_structure,
UX_INTERFACE_DESCRIPTOR_ENTRIES,
(UCHAR *) &interface_descriptor);
/* Memorize the interface we are scanning. */
current_interface = interface_descriptor.bInterfaceNumber;
}
/* Check the type for an interface descriptor. */
/* Check if the descriptor belongs to interface attached to this instance. */
if (descriptor_type == UX_HOST_CLASS_HID_DESCRIPTOR)
{
/* Ensure this interface is the one we need to scan. */
if (current_interface == hid -> ux_host_class_hid_interface -> ux_interface_descriptor.bInterfaceNumber)
{
/* Obtain the length of the HID descriptor. We need to make machine
independent first. */
_ux_utility_descriptor_parse(descriptor, _ux_system_hid_descriptor_structure,
UX_HID_DESCRIPTOR_ENTRIES, (UCHAR *) &hid_descriptor);
/* We have found the hid descriptor. Now we should get the HID report descriptor. */
status = _ux_host_class_hid_report_descriptor_get(hid, hid_descriptor.wItemLength);
/* No release, the memory will be released after all interface scan done(enumeration done). */
device -> ux_device_packed_configuration = start_descriptor;
/* Return completion status. */
return(status);
}
}
/* Verify if the descriptor is still valid. */
if (descriptor_length > total_configuration_length)
{
/* Error trap. */
_ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_DESCRIPTOR_CORRUPTED);
/* If trace is enabled, insert this event into the trace buffer. */
UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_DESCRIPTOR_CORRUPTED, descriptor, 0, 0, UX_TRACE_ERRORS, 0, 0)
/* Release the memory. */
_ux_utility_memory_free(start_descriptor);
/* Return an error. */
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_configuration_length -= descriptor_length;
}
}
/* Error trap. */
_ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_DESCRIPTOR_CORRUPTED);
/* If trace is enabled, insert this event into the trace buffer. */
UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_DESCRIPTOR_CORRUPTED, start_descriptor, 0, 0, UX_TRACE_ERRORS, 0, 0)
/* Free all used resources. */
if (device -> ux_device_packed_configuration == UX_NULL)
_ux_utility_memory_free(start_descriptor);
/* Return an error. */
return(UX_DESCRIPTOR_CORRUPTED);
}
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