qmk_firmware/Demos/Host/Incomplete/AudioInputHost/ConfigDescriptor.c

/*
             LUFA Library
     Copyright (C) Dean Camera, 2011.

  dean [at] fourwalledcubicle [dot] com
           www.lufa-lib.org
*/

/*
  Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, distribute, and sell this
  software and its documentation for any purpose is hereby granted
  without fee, provided that the above copyright notice appear in
  all copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \file
 *
 *  USB Device Configuration Descriptor processing routines, to determine the correct pipe configurations
 *  needed to communication with an attached USB device. Descriptors are special  computer-readable structures
 *  which the host requests upon device enumeration, to determine the device's capabilities and functions.
 */

#include "ConfigDescriptor.h"

uint8_t StreamingInterfaceIndex      = 0;
uint8_t StreamingInterfaceAltSetting = 0;
uint8_t StreamingEndpointAddress     = 0;

uint8_t ProcessConfigurationDescriptor(void)
{
	uint8_t  ConfigDescriptorData[512];
	void*    CurrConfigLocation = ConfigDescriptorData;
	uint16_t CurrConfigBytesRem;

	USB_Descriptor_Interface_t* AudioControlInterface   = NULL;
	USB_Descriptor_Interface_t* AudioStreamingInterface = NULL;
	USB_Descriptor_Endpoint_t*  DataINEndpoint          = NULL;

	/* Retrieve the entire configuration descriptor into the allocated buffer */
	switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
	{
		case HOST_GETCONFIG_Successful:
			break;
		case HOST_GETCONFIG_InvalidData:
			return InvalidConfigDataReturned;
		case HOST_GETCONFIG_BuffOverflow:
			return DescriptorTooLarge;
		default:
			return ControlError;
	}

	while (!(DataINEndpoint))
	{
		if (!(AudioControlInterface) ||
		    USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
		                              DComp_NextAudioInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
		{
			if (!(AudioControlInterface))
			{
				if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
											  DComp_NextAudioControlInterface) != DESCRIPTOR_SEARCH_COMP_Found)
				{
					/* Descriptor not found, error out */
					return NoCompatibleInterfaceFound;
				}

				/* Save the interface in case we need to refer back to it later */
				AudioControlInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);			
			}
		
			if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
										  DComp_NextAudioStreamInterface) != DESCRIPTOR_SEARCH_COMP_Found)
			{
				if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
											  DComp_NextAudioControlInterface) != DESCRIPTOR_SEARCH_COMP_Found)
				{
					/* Descriptor not found, error out */
					return NoCompatibleInterfaceFound;
				}

				/* Save the interface in case we need to refer back to it later */
				AudioControlInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
			}

			/* Save the interface in case we need to refer back to it later */
			AudioStreamingInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);

			/* Skip the remainder of the loop as we have not found an endpoint yet */
			continue;
		}

		/* Retrieve the endpoint address from the endpoint descriptor */
		USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);

		/* If the endpoint is a IN type endpoint */
		if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
		  DataINEndpoint = EndpointData;
	}

	StreamingInterfaceIndex      = AudioStreamingInterface->InterfaceNumber;
	StreamingInterfaceAltSetting = AudioStreamingInterface->AlternateSetting;
	StreamingEndpointAddress     = DataINEndpoint->EndpointAddress;

	/* Configure the HID data IN pipe */
	Pipe_ConfigurePipe(AUDIO_DATA_IN_PIPE, EP_TYPE_ISOCHRONOUS, PIPE_TOKEN_IN,
	                   DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, PIPE_BANK_DOUBLE);

	/* Valid data found, return success */
	return SuccessfulConfigRead;
}

uint8_t DComp_NextAudioControlInterface(void* CurrentDescriptor)
{
	USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);

	if (Header->Type == DTYPE_Interface)
	{
		USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);

		if ((Interface->Class    == AUDIO_CSCP_AudioClass) &&
		    (Interface->SubClass == AUDIO_CSCP_ControlSubclass) &&
		    (Interface->Protocol == AUDIO_CSCP_ControlProtocol))
		{
			return DESCRIPTOR_SEARCH_Found;
		}
	}

	return DESCRIPTOR_SEARCH_NotFound;
}

uint8_t DComp_NextAudioStreamInterface(void* CurrentDescriptor)
{
	USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);

	if (Header->Type == DTYPE_Interface)
	{
		USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);

		if ((Interface->Class    == AUDIO_CSCP_AudioClass) &&
		    (Interface->SubClass == AUDIO_CSCP_AudioStreamingSubclass) &&
		    (Interface->Protocol == AUDIO_CSCP_StreamingProtocol))
		{
			return DESCRIPTOR_SEARCH_Found;
		}
	}

	return DESCRIPTOR_SEARCH_NotFound;
}

uint8_t DComp_NextAudioInterfaceDataEndpoint(void* CurrentDescriptor)
{
	USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);

	if (Header->Type == DTYPE_Endpoint)
	{
		USB_Descriptor_Endpoint_t* Endpoint = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Endpoint_t);

		if ((Endpoint->Attributes & EP_TYPE_MASK) == EP_TYPE_ISOCHRONOUS)
		  return DESCRIPTOR_SEARCH_Found;
	}
	else if (Header->Type == DTYPE_Interface)
	{
		return DESCRIPTOR_SEARCH_Fail;
	}

	return DESCRIPTOR_SEARCH_NotFound;
}