Added ability to write protect Mass Storage disk write operations from the host OS.

Demos/Device/ClassDriver/MassStorage/Lib/SCSI.c

@@ -113,6 +113,9 @@ bool SCSI_DecodeSCSICommand(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
 		case SCSI_CMD_READ_10:
 			CommandSuccess = SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_READ);
 			break;
+		case SCSI_CMD_MODE_SENSE_6:
+			CommandSuccess = SCSI_Command_ModeSense_6(MSInterfaceInfo);
+			break;
 		case SCSI_CMD_TEST_UNIT_READY:
 		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
 		case SCSI_CMD_VERIFY_10:
@@ -281,6 +284,17 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	uint32_t BlockAddress;
 	uint16_t TotalBlocks;
 
+	/* Check if the disk is write protected or not */
+	if ((IsDataRead == DATA_WRITE) && DISK_READ_ONLY)
+	{
+		/* Block address is invalid, update SENSE key and return command fail */
+		SCSI_SET_SENSE(SCSI_SENSE_KEY_DATA_PROTECT,
+		               SCSI_ASENSE_WRITE_PROTECTED,
+		               SCSI_ASENSEQ_NO_QUALIFIER);
+
+		return false;		
+	}
+
 	/* 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]);
 
@@ -302,7 +316,7 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	/* Adjust the given block address to the real media address based on the selected LUN */
 	BlockAddress += ((uint32_t)MSInterfaceInfo->State.CommandBlock.LUN * LUN_MEDIA_BLOCKS);
 	#endif
-
+	
 	/* Determine if the packet is a READ (10) or WRITE (10) command, call appropriate function */
 	if (IsDataRead == DATA_READ)
 	  DataflashManager_ReadBlocks(MSInterfaceInfo, BlockAddress, TotalBlocks);
@@ -315,3 +329,24 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	return true;
 }
 
+/** Command processing for an issued SCSI MODE SENSE (6) command. This command returns various informational pages about
+ *  the SCSI device, as well as the device's Write Protect status.
+ *
+ *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
+ *
+ *  \return Boolean true if the command completed successfully, false otherwise.
+ */
+static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
+{
+	/* Send an empty header response with the Write Protect flag status */
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(DISK_READ_ONLY ? 0x80 : 0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_ClearIN();
+
+	/* Update the bytes transferred counter and succeed the command */
+	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= 4;
+
+	return true;
+}

Demos/Device/ClassDriver/MassStorage/Lib/SCSI.h

@@ -81,6 +81,7 @@
 			static bool SCSI_Command_Send_Diagnostic(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 			static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 			                                      const bool IsDataRead);
+			static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 		#endif
 
 #endif

Demos/Device/ClassDriver/MassStorage/MassStorage.h

@@ -73,6 +73,9 @@
 
 		/** Blocks in each LUN, calculated from the total capacity divided by the total number of Logical Units in the device. */
 		#define LUN_MEDIA_BLOCKS         (VIRTUAL_MEMORY_BLOCKS / TOTAL_LUNS)
+		
+		/** Indicates if the disk is write protected or not. */
+		#define DISK_READ_ONLY            false
 
 	/* Function Prototypes: */
 		void SetupHardware(void);

Demos/Device/ClassDriver/MassStorageKeyboard/Lib/DataflashManager.h

@@ -63,12 +63,6 @@
 		/** Total number of blocks of the virtual memory for reporting to the host as the device's total capacity. */
 		#define VIRTUAL_MEMORY_BLOCKS              (VIRTUAL_MEMORY_BYTES / VIRTUAL_MEMORY_BLOCK_SIZE)
 
-		/** Total number of logical drives within the device - must be non-zero. */
-		#define TOTAL_LUNS                          1
-
-		/** Blocks in each LUN, calculated from the total capacity divided by the total number of Logical Units in the device. */
-		#define LUN_MEDIA_BLOCKS                   (VIRTUAL_MEMORY_BLOCKS / TOTAL_LUNS)
-
 	/* Function Prototypes: */
 		void DataflashManager_WriteBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 		                                  const uint32_t BlockAddress,

Demos/Device/ClassDriver/MassStorageKeyboard/Lib/SCSI.c

@@ -113,6 +113,9 @@ bool SCSI_DecodeSCSICommand(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
 		case SCSI_CMD_READ_10:
 			CommandSuccess = SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_READ);
 			break;
+		case SCSI_CMD_MODE_SENSE_6:
+			CommandSuccess = SCSI_Command_ModeSense_6(MSInterfaceInfo);
+			break;
 		case SCSI_CMD_TEST_UNIT_READY:
 		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
 		case SCSI_CMD_VERIFY_10:
@@ -281,6 +284,17 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	uint32_t BlockAddress;
 	uint16_t TotalBlocks;
 
+	/* Check if the disk is write protected or not */
+	if ((IsDataRead == DATA_WRITE) && DISK_READ_ONLY)
+	{
+		/* Block address is invalid, update SENSE key and return command fail */
+		SCSI_SET_SENSE(SCSI_SENSE_KEY_DATA_PROTECT,
+		               SCSI_ASENSE_WRITE_PROTECTED,
+		               SCSI_ASENSEQ_NO_QUALIFIER);
+
+		return false;		
+	}
+
 	/* 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]);
 
@@ -315,3 +329,24 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	return true;
 }
 
+/** Command processing for an issued SCSI MODE SENSE (6) command. This command returns various informational pages about
+ *  the SCSI device, as well as the device's Write Protect status.
+ *
+ *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
+ *
+ *  \return Boolean true if the command completed successfully, false otherwise.
+ */
+static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
+{
+	/* Send an empty header response with the Write Protect flag status */
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(DISK_READ_ONLY ? 0x80 : 0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_ClearIN();
+
+	/* Update the bytes transferred counter and succeed the command */
+	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= 4;
+
+	return true;
+}

Demos/Device/ClassDriver/MassStorageKeyboard/Lib/SCSI.h

@@ -81,6 +81,7 @@
 			static bool SCSI_Command_Send_Diagnostic(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 			static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 			                                      const bool IsDataRead);
+			static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 		#endif
 
 #endif

Demos/Device/ClassDriver/MassStorageKeyboard/MassStorageKeyboard.h

@@ -73,6 +73,15 @@
 		/** LED mask for the library LED driver, to indicate that the USB interface is busy. */
 		#define LEDMASK_USB_BUSY         LEDS_LED2
 
+		/** Total number of logical drives within the device - must be non-zero. */
+		#define TOTAL_LUNS               1
+
+		/** Blocks in each LUN, calculated from the total capacity divided by the total number of Logical Units in the device. */
+		#define LUN_MEDIA_BLOCKS         (VIRTUAL_MEMORY_BLOCKS / TOTAL_LUNS)
+
+		/** Indicates if the disk is write protected or not. */
+		#define DISK_READ_ONLY           false
+		
 	/* Function Prototypes: */
 		void SetupHardware(void);
 

Demos/Device/LowLevel/MassStorage/Lib/SCSI.c

@@ -111,6 +111,9 @@ bool SCSI_DecodeSCSICommand(void)
 		case SCSI_CMD_READ_10:
 			CommandSuccess = SCSI_Command_ReadWrite_10(DATA_READ);
 			break;
+		case SCSI_CMD_MODE_SENSE_6:
+			CommandSuccess = SCSI_Command_ModeSense_6();
+			break;
 		case SCSI_CMD_TEST_UNIT_READY:
 		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
 		case SCSI_CMD_VERIFY_10:
@@ -278,9 +281,23 @@ static bool SCSI_Command_Send_Diagnostic(void)
  */
 static bool SCSI_Command_ReadWrite_10(const bool IsDataRead)
 {
-	uint32_t BlockAddress = SwapEndian_32(*(uint32_t*)&CommandBlock.SCSICommandData[2]);
+	uint32_t BlockAddress;
-	uint16_t TotalBlocks  = SwapEndian_16(*(uint16_t*)&CommandBlock.SCSICommandData[7]);
+	uint16_t TotalBlocks;
 
+	/* Check if the disk is write protected or not */
+	if ((IsDataRead == DATA_WRITE) && DISK_READ_ONLY)
+	{
+		/* Block address is invalid, update SENSE key and return command fail */
+		SCSI_SET_SENSE(SCSI_SENSE_KEY_DATA_PROTECT,
+		               SCSI_ASENSE_WRITE_PROTECTED,
+		               SCSI_ASENSEQ_NO_QUALIFIER);
+
+		return false;		
+	}
+
+	BlockAddress = SwapEndian_32(*(uint32_t*)&CommandBlock.SCSICommandData[2]);
+	TotalBlocks  = SwapEndian_16(*(uint16_t*)&CommandBlock.SCSICommandData[7]);
+	
 	/* Check if the block address is outside the maximum allowable value for the LUN */
 	if (BlockAddress >= LUN_MEDIA_BLOCKS)
 	{
@@ -309,3 +326,22 @@ static bool SCSI_Command_ReadWrite_10(const bool IsDataRead)
 	return true;
 }
 
+/** Command processing for an issued SCSI MODE SENSE (6) command. This command returns various informational pages about
+ *  the SCSI device, as well as the device's Write Protect status.
+ *
+ *  \return Boolean true if the command completed successfully, false otherwise.
+ */
+static bool SCSI_Command_ModeSense_6(void)
+{
+	/* Send an empty header response with the Write Protect flag status */
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(DISK_READ_ONLY ? 0x80 : 0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_ClearIN();
+
+	/* Update the bytes transferred counter and succeed the command */
+	CommandBlock.DataTransferLength -= 4;
+
+	return true;
+}

Demos/Device/LowLevel/MassStorage/Lib/SCSI.h

@@ -143,6 +143,7 @@
 			static bool SCSI_Command_Read_Capacity_10(void);
 			static bool SCSI_Command_Send_Diagnostic(void);
 			static bool SCSI_Command_ReadWrite_10(const bool IsDataRead);
+			static bool SCSI_Command_ModeSense_6(void);
 		#endif
 
 #endif

Demos/Device/LowLevel/MassStorage/MassStorage.h

@@ -68,6 +68,9 @@
 		/** LED mask for the library LED driver, to indicate that the USB interface is busy. */
 		#define LEDMASK_USB_BUSY           LEDS_LED2
 
+		/** Indicates if the disk is write protected or not. */
+		#define DISK_READ_ONLY            false
+
 	/* Global Variables: */
 		extern MS_CommandBlockWrapper_t  CommandBlock;
 		extern MS_CommandStatusWrapper_t CommandStatus;

LUFA/ManPages/ChangeLog.txt

@@ -12,6 +12,7 @@
   *   - None
   *  - Library Applications:
   *   - Added new incomplete MIDIToneGenerator project
+  *   - Added ability to write protect Mass Storage disk write operations from the host OS
   *
   *  <b>Changed:</b>
   *  - Core:

Projects/Incomplete/StandaloneProgrammer/Lib/DataflashManager.h

@@ -52,18 +52,21 @@
 
 	/* Defines: */
 		/** Total number of bytes of the storage medium, comprised of one or more dataflash ICs. */
-		#define VIRTUAL_MEMORY_BYTES                ((uint32_t)DATAFLASH_PAGES * DATAFLASH_PAGE_SIZE * DATAFLASH_TOTALCHIPS)
+		#define VIRTUAL_MEMORY_BYTES        ((uint32_t)DATAFLASH_PAGES * DATAFLASH_PAGE_SIZE * DATAFLASH_TOTALCHIPS)
 
 		/** Block size of the device. This is kept at 512 to remain compatible with the OS despite the underlying
 		 *  storage media (Dataflash) using a different native block size. Do not change this value.
 		 */
-		#define VIRTUAL_MEMORY_BLOCK_SIZE           512
+		#define VIRTUAL_MEMORY_BLOCK_SIZE   512
 
 		/** Total number of blocks of the virtual memory for reporting to the host as the device's total capacity. Do not
 		 *  change this value; change VIRTUAL_MEMORY_BYTES instead to alter the media size.
 		 */
-		#define VIRTUAL_MEMORY_BLOCKS               (VIRTUAL_MEMORY_BYTES / VIRTUAL_MEMORY_BLOCK_SIZE)
+		#define VIRTUAL_MEMORY_BLOCKS       (VIRTUAL_MEMORY_BYTES / VIRTUAL_MEMORY_BLOCK_SIZE)
 
+		/** Indicates if the disk is write protected or not. */
+		#define DISK_READ_ONLY              false
+		
 	/* Function Prototypes: */
 		#if defined(USB_CAN_BE_DEVICE)
 			void DataflashManager_WriteBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,

Projects/Incomplete/StandaloneProgrammer/Lib/SCSI.c

@@ -114,6 +114,9 @@ bool SCSI_DecodeSCSICommand(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
 		case SCSI_CMD_READ_10:
 			CommandSuccess = SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_READ);
 			break;
+		case SCSI_CMD_MODE_SENSE_6:
+			CommandSuccess = SCSI_Command_ModeSense_6(MSInterfaceInfo);
+			break;
 		case SCSI_CMD_TEST_UNIT_READY:
 		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
 		case SCSI_CMD_VERIFY_10:
@@ -282,6 +285,17 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	uint32_t BlockAddress;
 	uint16_t TotalBlocks;
 
+	/* Check if the disk is write protected or not */
+	if ((IsDataRead == DATA_WRITE) && DISK_READ_ONLY)
+	{
+		/* Block address is invalid, update SENSE key and return command fail */
+		SCSI_SET_SENSE(SCSI_SENSE_KEY_DATA_PROTECT,
+		               SCSI_ASENSE_WRITE_PROTECTED,
+		               SCSI_ASENSEQ_NO_QUALIFIER);
+
+		return false;		
+	}
+
 	/* 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]);
 
@@ -298,7 +312,7 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 
 		return false;
 	}
-
+	
 	/* Determine if the packet is a READ (10) or WRITE (10) command, call appropriate function */
 	if (IsDataRead == DATA_READ)
 	  DataflashManager_ReadBlocks(MSInterfaceInfo, BlockAddress, TotalBlocks);
@@ -310,5 +324,26 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 
 	return true;
 }
-#endif
 
+/** Command processing for an issued SCSI MODE SENSE (6) command. This command returns various informational pages about
+ *  the SCSI device, as well as the device's Write Protect status.
+ *
+ *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
+ *
+ *  \return Boolean true if the command completed successfully, false otherwise.
+ */
+static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
+{
+	/* Send an empty header response with the Write Protect flag status */
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(DISK_READ_ONLY ? 0x80 : 0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_ClearIN();
+
+	/* Update the bytes transferred counter and succeed the command */
+	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= 4;
+
+	return true;
+}
+#endif

Projects/Incomplete/StandaloneProgrammer/Lib/SCSI.h

@@ -82,6 +82,7 @@
 				static bool SCSI_Command_Send_Diagnostic(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 				static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 													  const bool IsDataRead);
+				static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 			#endif
 		#endif
 

Projects/TempDataLogger/Lib/SCSI.c

@@ -113,6 +113,9 @@ bool SCSI_DecodeSCSICommand(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
 		case SCSI_CMD_READ_10:
 			CommandSuccess = SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_READ);
 			break;
+		case SCSI_CMD_MODE_SENSE_6:
+			CommandSuccess = SCSI_Command_ModeSense_6(MSInterfaceInfo);
+			break;
 		case SCSI_CMD_TEST_UNIT_READY:
 		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
 		case SCSI_CMD_VERIFY_10:
@@ -281,6 +284,17 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	uint32_t BlockAddress;
 	uint16_t TotalBlocks;
 
+	/* Check if the disk is write protected or not */
+	if ((IsDataRead == DATA_WRITE) && DISK_READ_ONLY)
+	{
+		/* Block address is invalid, update SENSE key and return command fail */
+		SCSI_SET_SENSE(SCSI_SENSE_KEY_DATA_PROTECT,
+		               SCSI_ASENSE_WRITE_PROTECTED,
+		               SCSI_ASENSEQ_NO_QUALIFIER);
+
+		return false;		
+	}
+
 	/* 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]);
 
@@ -297,7 +311,7 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 
 		return false;
 	}
-
+	
 	/* Determine if the packet is a READ (10) or WRITE (10) command, call appropriate function */
 	if (IsDataRead == DATA_READ)
 	  DataflashManager_ReadBlocks(MSInterfaceInfo, BlockAddress, TotalBlocks);
@@ -310,3 +324,24 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	return true;
 }
 
+/** Command processing for an issued SCSI MODE SENSE (6) command. This command returns various informational pages about
+ *  the SCSI device, as well as the device's Write Protect status.
+ *
+ *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
+ *
+ *  \return Boolean true if the command completed successfully, false otherwise.
+ */
+static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
+{
+	/* Send an empty header response with the Write Protect flag status */
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(DISK_READ_ONLY ? 0x80 : 0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_ClearIN();
+
+	/* Update the bytes transferred counter and succeed the command */
+	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= 4;
+
+	return true;
+}

Projects/TempDataLogger/Lib/SCSI.h

@@ -81,6 +81,7 @@
 			static bool SCSI_Command_Send_Diagnostic(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 			static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 			                                      const bool IsDataRead);
+			static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 		#endif
 
 #endif

Projects/TempDataLogger/TempDataLogger.h

@@ -78,6 +78,9 @@
 		/** Default log interval when the EEPROM is blank, in 500ms ticks. */
 		#define DEFAULT_LOG_INTERVAL     20
 
+		/** Indicates if the disk is write protected or not. */
+		#define DISK_READ_ONLY           false
+
 	/* Type Defines: */
 		typedef struct
 		{

Projects/Webserver/Lib/DataflashManager.h

@@ -64,6 +64,9 @@
 		 */
 		#define VIRTUAL_MEMORY_BLOCKS               (VIRTUAL_MEMORY_BYTES / VIRTUAL_MEMORY_BLOCK_SIZE)
 
+		/** Indicates if the disk is write protected or not. */
+		#define DISK_READ_ONLY                      false
+
 	/* Function Prototypes: */
 		void DataflashManager_WriteBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 		                                  const uint32_t BlockAddress,

Projects/Webserver/Lib/SCSI.c

@@ -113,6 +113,9 @@ bool SCSI_DecodeSCSICommand(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
 		case SCSI_CMD_READ_10:
 			CommandSuccess = SCSI_Command_ReadWrite_10(MSInterfaceInfo, DATA_READ);
 			break;
+		case SCSI_CMD_MODE_SENSE_6:
+			CommandSuccess = SCSI_Command_ModeSense_6(MSInterfaceInfo);
+			break;
 		case SCSI_CMD_TEST_UNIT_READY:
 		case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
 		case SCSI_CMD_VERIFY_10:
@@ -281,6 +284,17 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	uint32_t BlockAddress;
 	uint16_t TotalBlocks;
 
+	/* Check if the disk is write protected or not */
+	if ((IsDataRead == DATA_WRITE) && DISK_READ_ONLY)
+	{
+		/* Block address is invalid, update SENSE key and return command fail */
+		SCSI_SET_SENSE(SCSI_SENSE_KEY_DATA_PROTECT,
+		               SCSI_ASENSE_WRITE_PROTECTED,
+		               SCSI_ASENSEQ_NO_QUALIFIER);
+
+		return false;		
+	}
+
 	/* 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]);
 
@@ -297,7 +311,7 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 
 		return false;
 	}
-
+	
 	/* Determine if the packet is a READ (10) or WRITE (10) command, call appropriate function */
 	if (IsDataRead == DATA_READ)
 	  DataflashManager_ReadBlocks(MSInterfaceInfo, BlockAddress, TotalBlocks);
@@ -310,3 +324,24 @@ static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfa
 	return true;
 }
 
+/** Command processing for an issued SCSI MODE SENSE (6) command. This command returns various informational pages about
+ *  the SCSI device, as well as the device's Write Protect status.
+ *
+ *  \param[in] MSInterfaceInfo  Pointer to the Mass Storage class interface structure that the command is associated with
+ *
+ *  \return Boolean true if the command completed successfully, false otherwise.
+ */
+static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo)
+{
+	/* Send an empty header response with the Write Protect flag status */
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_Write_Byte(DISK_READ_ONLY ? 0x80 : 0x00);
+	Endpoint_Write_Byte(0x00);
+	Endpoint_ClearIN();
+
+	/* Update the bytes transferred counter and succeed the command */
+	MSInterfaceInfo->State.CommandBlock.DataTransferLength -= 4;
+
+	return true;
+}

Projects/Webserver/Lib/SCSI.h

@@ -80,6 +80,7 @@
 			static bool SCSI_Command_Send_Diagnostic(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 			static bool SCSI_Command_ReadWrite_10(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 			                                      const bool IsDataRead);
+			static bool SCSI_Command_ModeSense_6(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo);
 		#endif
 
 #endif