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common/usbx_host_classes/src/ux_host_class_cdc_acm_capabilities_get.c
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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** USBX Component */
/** */
/** CDC ACM Class */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_host_class_cdc_acm.h"
#include "ux_host_stack.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_host_class_cdc_acm_capabilities_get PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function obtains the entire cdc_acm configuration descriptors. */
/* This is needed because the cdc_acm class needs to know if commands */
/* are routed through the comm interface or the data class. */
/* */
/* INPUT */
/* */
/* cdc_acm Pointer to cdc_acm class */
/* */
/* OUTPUT */
/* */
/* Completion Status */
/* */
/* CALLS */
/* */
/* _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 */
/* */
/* _ux_host_class_cdc_acm_activate */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Chaoqiong Xiao Initial Version 6.0 */
/* 09-30-2020 Chaoqiong Xiao Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _ux_host_class_cdc_acm_capabilities_get(UX_HOST_CLASS_CDC_ACM *cdc_acm)
{
UCHAR *descriptor;
UCHAR *saved_descriptor;
UX_ENDPOINT *control_endpoint;
UX_TRANSFER *transfer_request;
UX_CONFIGURATION configuration;
UX_INTERFACE_DESCRIPTOR interface_descriptor;
UINT status;
ULONG total_descriptor_length;
UCHAR descriptor_length;
UCHAR descriptor_type;
UCHAR descriptor_subtype;
ULONG interface_found;
/* We need to get the default control endpoint transfer request pointer. */
control_endpoint = &cdc_acm -> ux_host_class_cdc_acm_device -> ux_device_control_endpoint;
transfer_request = &control_endpoint -> ux_endpoint_transfer_request;
/* Need to allocate memory for the descriptor. */
descriptor = _ux_utility_memory_allocate(UX_SAFE_ALIGN, UX_CACHE_SAFE_MEMORY, UX_CONFIGURATION_DESCRIPTOR_LENGTH);
if (descriptor == UX_NULL)
return(UX_MEMORY_INSUFFICIENT);
/* Save this descriptor address since we need to free it. */
saved_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 = UX_CONFIGURATION_DESCRIPTOR_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 for correct transfer and entire descriptor returned. */
if ((status == UX_SUCCESS) && (transfer_request -> ux_transfer_request_actual_length == UX_CONFIGURATION_DESCRIPTOR_LENGTH))
{
/* The descriptor is in a packed format, parse it locally. */
_ux_utility_descriptor_parse(descriptor, _ux_system_configuration_descriptor_structure,
UX_CONFIGURATION_DESCRIPTOR_ENTRIES, (UCHAR *) &configuration.ux_configuration_descriptor);
/* Now we have the configuration descriptor which will tell us how many
bytes there are in the entire descriptor. */
total_descriptor_length = configuration.ux_configuration_descriptor.wTotalLength;
/* Free the previous descriptor. */
_ux_utility_memory_free(descriptor);
/* Allocate enough memory to read all descriptors attached
to this configuration. */
descriptor = _ux_utility_memory_allocate(UX_SAFE_ALIGN, UX_CACHE_SAFE_MEMORY, total_descriptor_length);
if (descriptor == UX_NULL)
return(UX_MEMORY_INSUFFICIENT);
/* Save this descriptor address since we need to free it. */
saved_descriptor = descriptor;
/* Set the length we need to retrieve. */
transfer_request -> ux_transfer_request_requested_length = total_descriptor_length;
/* And reprogram the descriptor buffer address. */
transfer_request -> ux_transfer_request_data_pointer = descriptor;
/* Send request to HCD layer. */
status = _ux_host_stack_transfer_request(transfer_request);
/* Check for correct transfer and entire descriptor returned. */
if ((status == UX_SUCCESS) && (transfer_request -> ux_transfer_request_actual_length == total_descriptor_length))
{
/* Default is Interface descriptor not yet found. */
interface_found = UX_FALSE;
/* Scan the descriptor for the CDC Comm interface. */
while (total_descriptor_length)
{
/* Gather the length, type and subtype of the descriptor. */
descriptor_length = *descriptor;
descriptor_type = *(descriptor + 1);
descriptor_subtype = *(descriptor + 2);
/* 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)
/* We can free the resource now. */
_ux_utility_memory_free(saved_descriptor);
/* Descriptor is corrupted. */
return(UX_DESCRIPTOR_CORRUPTED);
}
/* Process relative to descriptor type. */
switch (descriptor_type)
{
case 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);
/* Ensure we have the correct interface for Audio streaming. */
if ((interface_descriptor.bInterfaceClass == UX_HOST_CLASS_CDC_CONTROL_CLASS) &&
((interface_descriptor.bInterfaceSubClass == UX_HOST_CLASS_CDC_ACM_SUBCLASS) ||
(interface_descriptor.bInterfaceSubClass == UX_HOST_CLASS_CDC_DLC_SUBCLASS)))
{
/* Mark we have found it. */
interface_found = UX_TRUE;
}
else
{
/* Haven't found it. */
interface_found = UX_FALSE;
}
break;
case UX_HOST_CLASS_CDC_ACM_CS_INTERFACE:
/* First make sure we have found the correct generic interface descriptor. */
if ((interface_found == UX_TRUE) && (descriptor_subtype == UX_HOST_CLASS_CDC_ACM_CALL_MANAGEMENT_DESCRIPTOR))
{
/* Retrieve the bmCapabilities field which indicates how ACM commands are sent to the device. */
cdc_acm -> ux_host_class_cdc_acm_capabilities = *(descriptor + UX_HOST_CLASS_CDC_ACM_CALL_MANAGEMENT_CAPABILITIES);
}
break;
}
/* Verify if the descriptor is still valid. */
if (descriptor_length > total_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, descriptor, 0, 0, UX_TRACE_ERRORS, 0, 0)
/* We can free the resource now. */
_ux_utility_memory_free(saved_descriptor);
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 can free the resource now. */
_ux_utility_memory_free(saved_descriptor);
return(UX_SUCCESS);
}
}
/* Free all used resources. */
_ux_utility_memory_free(saved_descriptor);
/* Return completion status. */
return(status);
}