diff options
Diffstat (limited to 'Demos/Host/LowLevel/AudioOutputHost/ConfigDescriptor.c')
| -rw-r--r-- | Demos/Host/LowLevel/AudioOutputHost/ConfigDescriptor.c | 220 | 
1 files changed, 220 insertions, 0 deletions
| diff --git a/Demos/Host/LowLevel/AudioOutputHost/ConfigDescriptor.c b/Demos/Host/LowLevel/AudioOutputHost/ConfigDescriptor.c new file mode 100644 index 0000000000..c9d442107b --- /dev/null +++ b/Demos/Host/LowLevel/AudioOutputHost/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*  DataOUTEndpoint         = 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 (!(DataOUTEndpoint)) +	{ +		/* 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 OUT type endpoint */ +		if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_OUT) +		  DataOUTEndpoint = EndpointData; +	} + +	StreamingInterfaceIndex      = AudioStreamingInterface->InterfaceNumber; +	StreamingInterfaceAltSetting = AudioStreamingInterface->AlternateSetting; +	StreamingEndpointAddress     = DataOUTEndpoint->EndpointAddress; + +	/* Configure the Audio data OUT pipe */ +	Pipe_ConfigurePipe(AUDIO_DATA_OUT_PIPE, EP_TYPE_ISOCHRONOUS, DataOUTEndpoint->EndpointAddress, DataOUTEndpoint->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; +} + | 
