1 files changed, 220 insertions, 0 deletions
diff --git a/Demos/Host/LowLevel/AudioInputHost/ConfigDescriptor.c b/Demos/Host/LowLevel/AudioInputHost/ConfigDescriptor.c
new file mode 100644
index 000000000..81ebf9d85
--- /dev/null
+++ b/Demos/Host/LowLevel/AudioInputHost/ConfigDescriptor.c
@@ -0,0 +1,220 @@
+/*
+             LUFA Library
+     Copyright (C) Dean Camera, 2017.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+/*
+  Copyright 2017  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 disclaims 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"
+
+/** Index of the currently used Audio Streaming Interface within the device. */
+uint8_t StreamingInterfaceIndex      = 0;
+
+/** Alternative Setting of the currently used Audio Streaming Interface within the device. */
+uint8_t StreamingInterfaceAltSetting = 0;
+
+/** Address of the streaming audio endpoint currently in use within the device. */
+uint8_t StreamingEndpointAddress     = 0;
+
+
+/** Reads and processes an attached device's descriptors, to determine compatibility and pipe configurations. This
+ *  routine will read in the entire configuration descriptor, and configure the hosts pipes to correctly communicate
+ *  with compatible devices.
+ *
+ *  This routine searches for a Streaming Audio interface descriptor containing a valid Isochronous audio endpoint.
+ *
+ *  \return An error code from the \ref AudioHost_GetConfigDescriptorDataCodes_t enum.
+ */
+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))
+	{
+		/* See if we've found a likely compatible interface, and if there is an endpoint within that interface */
+		if (!(AudioControlInterface) ||
+		    USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
+		                              DComp_NextAudioInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
+		{
+			/* Check if we haven't found an Audio Control interface yet, or if we have run out of related Audio Streaming interfaces */
+			if (!(AudioControlInterface) ||
+			    USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
+			                              DComp_NextAudioStreamInterface) != DESCRIPTOR_SEARCH_COMP_Found)
+			{
+				/* Find a new Audio Control interface if the current one doesn't contain a compatible streaming interface */
+				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);
+
+				/* Find the next Audio Streaming interface within that Audio Control interface */
+				if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
+				                              DComp_NextAudioStreamInterface) != DESCRIPTOR_SEARCH_COMP_Found)
+				{
+					/* Descriptor not found, error out */
+					return NoCompatibleInterfaceFound;
+				}
+			}
+
+			/* 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);
+
+		/* Save the endpoint if it is an IN type endpoint */
+		if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_IN)
+		  DataINEndpoint = EndpointData;
+	}
+
+	StreamingInterfaceIndex      = AudioStreamingInterface->InterfaceNumber;
+	StreamingInterfaceAltSetting = AudioStreamingInterface->AlternateSetting;
+	StreamingEndpointAddress     = DataINEndpoint->EndpointAddress;
+
+	/* Configure the Audio data IN pipe */
+	Pipe_ConfigurePipe(AUDIO_DATA_IN_PIPE, EP_TYPE_ISOCHRONOUS, DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, 2);
+
+	/* Valid data found, return success */
+	return SuccessfulConfigRead;
+}
+
+/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
+ *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
+ *  descriptor processing if an incompatible descriptor configuration is found.
+ *
+ *  This comparator searches for the next Interface descriptor of the correct Audio Control Class, Subclass and Protocol values.
+ *
+ *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
+ */
+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;
+}
+
+/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
+ *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
+ *  descriptor processing if an incompatible descriptor configuration is found.
+ *
+ *  This comparator searches for the next Interface descriptor of the correct Audio Streaming Class, Subclass and Protocol values.
+ *
+ *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
+ */
+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;
+}
+
+/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
+ *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
+ *  descriptor processing if an incompatible descriptor configuration is found.
+ *
+ *  This comparator searches for the next Isochronous Endpoint descriptor within the current interface, aborting the
+ *  search if another interface descriptor is found before the next endpoint.
+ *
+ *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
+ */
+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;
+}
+