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

3 files changed, 40 insertions, 1 deletions

diff --git a/Projects/Webserver/Lib/DataflashManager.h b/Projects/Webserver/Lib/DataflashManager.h
index acbeba54c..a53c88776 100644
--- a/Projects/Webserver/Lib/DataflashManager.h
+++ b/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,
diff --git a/Projects/Webserver/Lib/SCSI.c b/Projects/Webserver/Lib/SCSI.c
index b1e88dc70..6a51c74e8 100644
--- a/Projects/Webserver/Lib/SCSI.c
+++ b/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;
+}
diff --git a/Projects/Webserver/Lib/SCSI.h b/Projects/Webserver/Lib/SCSI.h
index 8eae210f1..8360234b5 100644
--- a/Projects/Webserver/Lib/SCSI.h
+++ b/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