/*
             LUFA Library
     Copyright (C) Dean Camera, 2010.
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
  Copyright 2010  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
 *
 *  SCSI command processing routines, for SCSI commands issued by the host. Mass Storage
 *  devices use a thin "Bulk-Only Transport" protocol for issuing commands and status information,
 *  which wrap around standard SCSI device commands for controlling the actual storage medium.
 */
 
#define  INCLUDE_FROM_SCSI_C
#include "SCSI.h"

/** Structure to hold the SCSI response data to a SCSI INQUIRY command. This gives information about the device's
 *  features and capabilities.
 */
SCSI_Inquiry_Response_t InquiryData = 
	{
		.DeviceType          = DEVICE_TYPE_BLOCK,
		.PeripheralQualifier = 0,
			
		.Removable           = true,
			
		.Version             = 0,
			
		.ResponseDataFormat  = 2,
		.NormACA             = false,
		.TrmTsk              = false,
		.AERC                = false,

		.AdditionalLength    = 0x1F,
			
		.SoftReset           = false,
		.CmdQue              = false,
		.Linked              = false,
		.Sync                = false,
		.WideBus16Bit        = false,
		.WideBus32Bit        = false,
		.RelAddr             = false,
		
		.VendorID            = "LUFA",
		.ProductID           = "Dataflash Disk",
		.RevisionID          = {'0','.','0','0'},
	};

/** Structure to hold the sense data for the last issued SCSI command, which is returned to the host after a SCSI REQUEST SENSE
 *  command is issued. This gives information on exactly why the last command failed to complete.
 */
SCSI_Request_Sense_Response_t SenseData =
	{
		.ResponseCode        = 0x70,
		.AdditionalLength    = 0x0A,
	};


/** Main routine to process the SCSI command located in the Command Block Wrapper read from the host. This dispatches
 *  to the appropriate SCSI command handling routine if the issued command is supported by the device, else it returns
 *  a command failure due to a ILLEGAL REQUEST.
 *
 *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
 */
bool SCSI_DecodeSCSICommand(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
{
	/* Set initial sense data, before the requested command is processed */
	SCSI_SET_SENSE(SCSI_SENSE_KEY_GOOD,
	               SCSI_ASENSE_NO_ADDITIONAL_INFORMATION,
	               SCSI_ASENSEQ_NO_QUALIFIER);
					   
	/* Run the appropriate SCSI command hander function based on the passed command */
	switch (MSInterfaceInfo->State.CommandBlock.SCSICommandData[0])
	{
		case SCSI_CMD_INQUIRY:
			SCSI_Command_Inquiry(MSInterfaceInfo);			
			break;
		case SCSI_CMD_REQUEST_SENSE:
			SCSI_Command_Request_Sense(MSInterfaceInfo);
			break;
		case SCSI_CMD_READ_CAPACITY_10:
			SCSI_Command_Read_Capacity_10(MSInterfaceInfo);			
			break;
		case SCSI_CMD_SEND_DIAGNOSTIC:
			SCSI_Command_Send_Diagnostic(MSInterfaceInfo);
			break;
		case SCSI_CMD_WRITE_10:
			SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_WRITE);
			break;
		case SCSI_CMD_READ_10:
			SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_READ);
			break;
		case SCSI_CMD_TEST_UNIT_READY:
		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
		case SCSI_CMD_VERIFY_10:
			/* These commands should just succeed, no handling required */
			MSInterfaceInfo->State.CommandBlock.DataTransferLength = 0;
			break;
		default:
			/* Update the SENSE key to reflect the invalid command */
			SCSI_SET_SENSE(SCSI_SENSE_KEY_ILLEGAL_REQUEST,
		                   SCSI_ASENSE_INVALID_COMMAND,
		                   SCSI_ASENSEQ_NO_QUALIFIER);
			break;
	}

	return (SenseData.SenseKey == SCSI_SENSE_KEY_GOOD);
}

/** Command processing for an issued SCSI INQUIRY command. This command returns information about the device's features
 *  and capabilities to the host.
 *
 *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
 */
static void SCSI_Command_Inquiry(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
{
	uint16_t AllocationLength  = (((uint16_t)MSInterfaceInfo->State.CommandBlock.SCSICommandData[3] << 8) |
	                                         MSInterfaceInfo->State.CommandBlock.SCSICommandData[4]);
	uint16_t BytesTransferred  = (AllocationLength < sizeof(InquiryData))? AllocationLength :
	                                                                       sizeof(InquiryData);

	/* Only the standard INQUIRY data is supported, check if any optional INQUIRY bits set */
	if ((MSInterfaceInfo->State.CommandBlock.SCSICommandData[1] & ((1 << 0) | (1 << 1))) ||
	     MSInterfaceInfo->State.CommandBlock.SCSICommandData[2])
	{
		/* Optional but unsupported bits set - update the SENSE key and fail the request */
		SCSI_SET_SENSE(SCSI_SENSE_KEY_ILLEGAL_REQUEST,
		               SCSI_ASENSE_INVALID_FIELD_IN_CDB,
		               SCSI_ASENSEQ_NO_QUALIFIER);

		return;
	}
	
	Endpoint_Write_Stream_LE(&InquiryData, BytesTransferred, NO_STREAM_CALLBACK);

	uint8_t PadBytes[AllocationLength - BytesTransferred];
	
	/* Pad out remaining bytes with 0x00 */
	Endpoint_Write_Stream_LE(&PadBytes, sizeof(PadBytes), NO_STREAM_CALLBACK);

	/* Finalize the stream transfer to send the last packet */
	Endpoint_ClearIN();

	/* Succeed the command and update the bytes transferred counter */
	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= BytesTransferred;
}

/** Command processing for an issued SCSI REQUEST SENSE command. This command returns information about the last issued command,
 *  including the error code and additional error information so that the host can determine why a command failed to complete.
 *
 *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
 */
static void SCSI_Command_Request_Sense(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
{
	uint8_t  AllocationLength = MSInterfaceInfo->State.CommandBlock.SCSICommandData[4];
	uint8_t  BytesTransferred = (AllocationLength < sizeof(SenseData))? AllocationLength : sizeof(SenseData);
	
	uint8_t PadBytes[AllocationLength - BytesTransferred];

	Endpoint_Write_Stream_LE(&SenseData, BytesTransferred, NO_STREAM_CALLBACK);
	Endpoint_Write_Stream_LE(&PadBytes, sizeof(PadBytes), NO_STREAM_CALLBACK);
	Endpoint_ClearIN();

	/* Succeed the command and update the bytes transferred counter */
	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= BytesTransferred;
}

/** Command processing for an issued SCSI READ CAPACITY (10) command. This command returns information about the device's capacity
 *  on the selected Logical Unit (drive), as a number of OS-sized blocks.
 *
 *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
 */
static void SCSI_Command_Read_Capacity_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
{
	uint32_t LastBlockAddressInLUN = (VIRTUAL_MEMORY_BLOCKS - 1);
	uint32_t MediaBlockSize        = VIRTUAL_MEMORY_BLOCK_SIZE;

	Endpoint_Write_Stream_BE(&LastBlockAddressInLUN, sizeof(LastBlockAddressInLUN), NO_STREAM_CALLBACK);
	Endpoint_Write_Stream_BE(&MediaBlockSize, sizeof(MediaBlockSize), NO_STREAM_CALLBACK);
	Endpoint_ClearIN();
	
	/* Succeed the command and update the bytes transferred counter */
	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= 8;
}

/** Command processing for an issued SCSI SEND DIAGNOSTIC command. This command performs a quick check of the Dataflash ICs on the
 *  board, and indicates if they are present and functioning correctly. Only the Self-Test portion of the diagnostic command is
 *  supported.
 *
 *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
 */
static void SCSI_Command_Send_Diagnostic(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
{
	/* Check to see if the SELF TEST bit is not set */
	if (!(MSInterfaceInfo->State.CommandBlock.SCSICommandData[1] & (1 << 2)))
	{
		/* Only self-test supported - update SENSE key and fail the command */
		SCSI_SET_SENSE(SCSI_SENSE_KEY_ILLEGAL_REQUEST,
		               SCSI_ASENSE_INVALID_FIELD_IN_CDB,
		               SCSI_ASENSEQ_NO_QUALIFIER);

		return;
	}
	
	/* Check to see if all attached Dataflash ICs are functional */
	if (!(DataflashManager_CheckDataflashOperation()))
	{
		/* Update SENSE key with a hardware error condition and return command fail */
		SCSI_SET_SENSE(SCSI_SENSE_KEY_HARDWARE_ERROR,
		               SCSI_ASENSE_NO_ADDITIONAL_INFORMATION,
		               SCSI_ASENSEQ_NO_QUALIFIER);	
	
		return;
	}
	
	/* Succeed the command and update the bytes transferred counter */
	MSInterfaceInfo->State.CommandBlock.DataTransferLength = 0;
}

/** Command processing for an issued SCSI READ (10) or WRITE (10) command. This command reads in the block start address
 *  and total number of blocks to process, then calls the appropriate low-level dataflash routine to handle the actual
 *  reading and writing of the data.
 *
 *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
 *  \param[in] IsDataRead  Indicates if the command is a READ (10) command or WRITE (10) command (DATA_READ or DATA_WRITE)
 */
static void SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo, const bool IsDataRead)
{
	uint32_t BlockAddress;
	uint16_t TotalBlocks;
	
	/* Load in the 32-bit block address (SCSI uses big-endian, so have to reverse the byte order) */
	BlockAddress = SwapEndian_32(*(uint32_t*)&MSInterfaceInfo->State.CommandBlock.SCSICommandData[2]);

	/* Load in the 16-bit total blocks (SCSI uses big-endian, so have to reverse the byte order) */
	TotalBlocks  = SwapEndian_16(*(uint16_t*)&MSInterfaceInfo->State.CommandBlock.SCSICommandData[7]);
	
	/* Check if the block address is outside the maximum allowable value for the LUN */
	if (BlockAddress >= VIRTUAL_MEMORY_BLOCKS)
	{
		/* Block address is invalid, update SENSE key and return command fail */
		SCSI_SET_SENSE(SCSI_SENSE_KEY_ILLEGAL_REQUEST,
		               SCSI_ASENSE_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE,
		               SCSI_ASENSEQ_NO_QUALIFIER);

		return;
	}
	
	/* Determine if the packet is a READ (10) or WRITE (10) command, call appropriate function */
	if (IsDataRead == DATA_READ)
	  DataflashManager_ReadBlocks(MSInterfaceInfo, BlockAddress, TotalBlocks);
	else
	  DataflashManager_WriteBlocks(MSInterfaceInfo, BlockAddress, TotalBlocks);

	/* Update the bytes transferred counter and succeed the command */
	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= ((uint32_t)TotalBlocks * VIRTUAL_MEMORY_BLOCK_SIZE);
}