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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 */
/** */
/** Audio Class */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_host_class_audio.h"
#include "ux_host_stack.h"
#if defined(UX_HOST_CLASS_AUDIO_2_SUPPORT)
static inline UINT _ux_host_class_audio_alternate_setting_locate_2(
UX_HOST_CLASS_AUDIO *audio,
UX_HOST_CLASS_AUDIO_SAMPLING *audio_sampling,
UINT *alternate_setting);
#endif
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_host_class_audio_alternate_setting_locate PORTABLE C */
/* 6.1.12 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function finds the right alternate setting according to the */
/* sampling desired. */
/* */
/* INPUT */
/* */
/* audio Pointer to audio class */
/* audio_sampling Pointer to audio sampling */
/* alternate_setting Pointer to located alternate */
/* setting */
/* */
/* OUTPUT */
/* */
/* Completion Status */
/* */
/* CALLS */
/* */
/* _ux_utility_descriptor_parse Parse descriptor */
/* */
/* CALLED BY */
/* */
/* Audio Class */
/* */
/**************************************************************************/
UINT _ux_host_class_audio_alternate_setting_locate(UX_HOST_CLASS_AUDIO *audio, UX_HOST_CLASS_AUDIO_SAMPLING *audio_sampling,
UINT *alternate_setting)
{
#if defined(UX_HOST_CLASS_AUDIO_2_SUPPORT)
return(_ux_host_class_audio_alternate_setting_locate_2(audio, audio_sampling, alternate_setting));
#else
UCHAR * descriptor;
UX_INTERFACE_DESCRIPTOR interface_descriptor;
UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR audio_interface_descriptor;
ULONG total_descriptor_length;
UINT descriptor_length;
UINT descriptor_type;
UINT descriptor_subtype;
UINT interface_found;
ULONG lower_frequency;
ULONG higher_frequency;
UINT specific_frequency_count;
/* Get the descriptor to the entire configuration. */
descriptor = audio -> ux_host_class_audio_configuration_descriptor;
total_descriptor_length = audio -> ux_host_class_audio_configuration_descriptor_length;
/* Default is Interface descriptor not yet found. */
interface_found = UX_FALSE;
/* Scan the descriptor for the Audio Streaming interface. */
while (total_descriptor_length)
{
/* Gather the length, type and subtype of the descriptor. */
descriptor_length = *descriptor;
/* 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)
return(UX_DESCRIPTOR_CORRUPTED);
}
descriptor_type = *(descriptor + 1);
descriptor_subtype = *(descriptor + 2);
/* 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_AUDIO_CLASS) &&
(interface_descriptor.bInterfaceSubClass == UX_HOST_CLASS_AUDIO_SUBCLASS_STREAMING))
{
/* Mark we have found it. */
interface_found = UX_TRUE;
/* And memorize the alternate setting. */
*alternate_setting = interface_descriptor.bAlternateSetting;
}
else
{
/* Haven't found it. */
interface_found = UX_FALSE;
}
break;
case UX_HOST_CLASS_AUDIO_CS_INTERFACE:
/* First make sure we have found the correct generic interface descriptor. */
if ((interface_found == UX_TRUE) && (descriptor_subtype == UX_HOST_CLASS_AUDIO_CS_FORMAT_TYPE))
{
/* Parse the FORMAT_TYPE descriptor and make it machine independent. */
_ux_utility_descriptor_parse(descriptor, _ux_system_class_audio_interface_descriptor_structure,
UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_ENTRIES, (UCHAR *) &audio_interface_descriptor);
/* This descriptor must refer to a PCM audio type. */
if (audio_interface_descriptor.bFormatType != UX_HOST_CLASS_AUDIO_FORMAT_TYPE_I)
break;
/* The number of channels demanded by the application must match. */
if (audio_sampling -> ux_host_class_audio_sampling_channels != audio_interface_descriptor.bNrChannels)
break;
/* The resolution demanded by the application must match. */
if (audio_sampling -> ux_host_class_audio_sampling_resolution != audio_interface_descriptor.bBitResolution)
break;
/* Check the frequency demanded. The descriptor frequency is either defined
as a min and max frequency or an array of specified values. */
if (audio_interface_descriptor.bSamFreqType == 0)
{
if (descriptor_length < (UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 6))
{
/* 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)
return(UX_DESCRIPTOR_CORRUPTED);
}
/* The declaration of frequency is contiguous, so get the minimum and maximum */
lower_frequency = (ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH) |
((ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 1)) << 8 |
((ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 2)) << 16;
higher_frequency = (ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 3) |
((ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 4)) << 8 |
((ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 5)) << 16;
/* Now compare with what is required. */
if ((audio_sampling -> ux_host_class_audio_sampling_frequency >= lower_frequency) &&
(audio_sampling -> ux_host_class_audio_sampling_frequency <= higher_frequency))
{
/* We have found the right alternate setting. */
audio -> ux_host_class_audio_sampling_descriptor = descriptor;
return(UX_SUCCESS);
}
}
else
{
if (descriptor_length < (UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + (UINT)(3 * audio_interface_descriptor.bSamFreqType)))
{
return(UX_DESCRIPTOR_CORRUPTED);
}
/* The declaration of the frequency is declared as an array of specific values. */
for (specific_frequency_count = 0; specific_frequency_count < audio_interface_descriptor.bSamFreqType;
specific_frequency_count++)
{
lower_frequency = (ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + (specific_frequency_count * 3)) |
((ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 1 + (specific_frequency_count * 3))) << 8 |
((ULONG) *(descriptor + UX_HOST_CLASS_AUDIO_INTERFACE_DESCRIPTOR_LENGTH + 2 + (specific_frequency_count * 3))) << 16;
/* Now compare with what is required. */
if (audio_sampling -> ux_host_class_audio_sampling_frequency == lower_frequency)
{
/* We have found the right alternate setting. */
audio -> ux_host_class_audio_sampling_descriptor = descriptor;
return(UX_SUCCESS);
}
}
}
}
break;
}
/* Verify if the descriptor is still valid. */
if (descriptor_length > total_descriptor_length)
{
/* 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)
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;
}
/* If trace is enabled, insert this event into the trace buffer. */
UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_NO_ALTERNATE_SETTING, audio, 0, 0, UX_TRACE_ERRORS, 0, 0)
/* We get here when either the report descriptor has a problem or we could
not find the right audio device. */
return(UX_NO_ALTERNATE_SETTING);
#endif
}
#if defined(UX_HOST_CLASS_AUDIO_2_SUPPORT)
struct UX_HOST_CLASS_AUDIO_ALT_LOCATE_PARSER {
UX_HOST_CLASS_AUDIO_SAMPLING *sampling;
UCHAR *clock_descriptor;
ULONG alt;
UINT status;
};
static UINT _ux_host_class_audio_alt_locate_parse(VOID *arg,
UCHAR *packed_interface_descriptor,
UX_HOST_CLASS_AUDIO_SAMPLING_CHARACTERISTICS *sam_attr)
{
struct UX_HOST_CLASS_AUDIO_ALT_LOCATE_PARSER *parser = (struct UX_HOST_CLASS_AUDIO_ALT_LOCATE_PARSER *)arg;
UX_HOST_CLASS_AUDIO_SAMPLING *sampling = parser -> sampling;
ULONG frequency_low, frequency_high;
/* Check bNrChannels. */
if (sampling -> ux_host_class_audio_sampling_channels !=
sam_attr -> ux_host_class_audio_sampling_characteristics_channels)
return(0);
/* Check bBitResolution. */
if (sampling -> ux_host_class_audio_sampling_resolution !=
sam_attr -> ux_host_class_audio_sampling_characteristics_resolution)
return(0);
/* Calculate frequency low. */
frequency_low = sam_attr -> ux_host_class_audio_sampling_characteristics_frequency_low;
if (UX_OVERFLOW_CHECK_MULV_ULONG(frequency_low, sam_attr -> ux_host_class_audio_sampling_characteristics_clock_mul))
{
/* Math error. */
parser -> status = UX_MATH_OVERFLOW;
return(1);
}
frequency_low *= sam_attr -> ux_host_class_audio_sampling_characteristics_clock_mul;
frequency_low /= sam_attr -> ux_host_class_audio_sampling_characteristics_clock_div;
/* Calculate frequency high. */
frequency_high = sam_attr -> ux_host_class_audio_sampling_characteristics_frequency_high;
if (UX_OVERFLOW_CHECK_MULV_ULONG(frequency_high, sam_attr -> ux_host_class_audio_sampling_characteristics_clock_mul))
{
/* Math error. */
parser -> status = UX_MATH_OVERFLOW;
return(1);
}
frequency_high *= sam_attr -> ux_host_class_audio_sampling_characteristics_clock_mul;
frequency_high /= sam_attr -> ux_host_class_audio_sampling_characteristics_clock_div;
/* Check frequency in [low, high]. */
if ((frequency_low <= sampling -> ux_host_class_audio_sampling_frequency) &&
(frequency_high >= sampling -> ux_host_class_audio_sampling_frequency))
{
/* Save bAlternateSetting @ 3. */
parser -> alt = (ULONG)packed_interface_descriptor[3];
/* Save UAC 1.0 FormatTypeI or UAC 2.0 CSD. */
parser -> clock_descriptor =
sam_attr -> ux_host_class_audio_sampling_characteristics_descriptor;
return(1);
}
/* Continue parsing. */
return(0);
}
static inline UINT _ux_host_class_audio_alternate_setting_locate_2(
UX_HOST_CLASS_AUDIO *audio,
UX_HOST_CLASS_AUDIO_SAMPLING *audio_sampling,
UINT *alternate_setting)
{
struct UX_HOST_CLASS_AUDIO_ALT_LOCATE_PARSER parser;
UINT status;
/* Parse specific sampling setting to get alt setting. */
parser.sampling = audio_sampling;
parser.clock_descriptor = UX_NULL;
parser.alt = 0xFF;
parser.status = UX_SUCCESS;
status = _ux_host_class_audio_raw_sampling_parse(audio, _ux_host_class_audio_alt_locate_parse, (VOID*)&parser);
/* Check descriptor error. */
if (status != UX_SUCCESS)
return(status);
/* Check if valid alternate setting is found. */
if (parser.alt == 0xFF)
{
/* If trace is enabled, insert this event into the trace buffer. */
UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_NO_ALTERNATE_SETTING, audio, 0, 0, UX_TRACE_ERRORS, 0, 0)
return(UX_NO_ALTERNATE_SETTING);
}
/* Save alternate setting. */
*alternate_setting = parser.alt;
audio -> ux_host_class_audio_sampling_descriptor = parser.clock_descriptor;
return(parser.status);
}
#endif
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