From 9b153b3e06deb9104ca972f224bb545ed3836ec2 Mon Sep 17 00:00:00 2001
From: Richard Barry <ribarry@amazon.com>
Date: Tue, 14 May 2013 13:22:37 +0000
Subject: [PATCH] Ensure the SmartFusion2 interrupt driven UART drivers are not
 passed a zero length buffer.

---
 .../RTOSDemo/.cproject                        |  2 +-
 .../RTOSDemo/Full-Demo/UARTCommandConsole.c   | 23 +++++++++++--------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/.cproject b/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/.cproject
index e76a18d35..ac1387499 100644
--- a/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/.cproject
+++ b/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/.cproject
@@ -50,7 +50,7 @@
 </option>
 <option id="gnu.c.compiler.option.misc.verbose.1351799799" name="Verbose (-v)" superClass="gnu.c.compiler.option.misc.verbose" value="true" valueType="boolean"/>
 <option id="gnu.c.compiler.option.optimization.flags.435998408" name="Other optimization flags" superClass="gnu.c.compiler.option.optimization.flags" value="-ffunction-sections -fdata-sections" valueType="string"/>
-<option id="gnu.c.compiler.option.misc.other.1001754914" superClass="gnu.c.compiler.option.misc.other" value="-c -fmessage-length=0 -Wextra" valueType="string"/>
+<option id="gnu.c.compiler.option.misc.other.1001754914" name="Other flags" superClass="gnu.c.compiler.option.misc.other" value="-c -fmessage-length=0 -Wextra" valueType="string"/>
 <inputType id="cdt.managedbuild.tool.gnu.c.compiler.input.2036217646" superClass="cdt.managedbuild.tool.gnu.c.compiler.input"/>
 </tool>
 <tool id="cdt.managedbuild.tool.gnu.cpp.compiler.cross.cortexm3.exe.debug.612642130" name="GNU C++ Compiler" superClass="cdt.managedbuild.tool.gnu.cpp.compiler.cross.cortexm3.exe.debug">
diff --git a/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/Full-Demo/UARTCommandConsole.c b/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/Full-Demo/UARTCommandConsole.c
index 19d758c1f..73aa0178e 100644
--- a/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/Full-Demo/UARTCommandConsole.c
+++ b/FreeRTOS/Demo/CORTEX_SmartFusion2_M2S050_SoftConsole/RTOSDemo/Full-Demo/UARTCommandConsole.c
@@ -240,17 +240,20 @@ static void prvSendBuffer( const uint8_t * pcBuffer, size_t xBufferLength )
 {
 const portTickType xVeryShortDelay = 2UL;
 
-	MSS_UART_irq_tx( ( mss_uart_instance_t * ) pxUART, pcBuffer, xBufferLength );
-
-	/* Ensure any previous transmissions have completed.  The default UART
-	interrupt does not provide an event based method of	signally the end of a Tx
-	- this is therefore a crude poll of the Tx end status.  Replacing the
-	default UART handler with one that 'gives' a semaphore when the Tx is
-	complete would allow this poll loop to be replaced by a simple semaphore
-	block. */
-	while( MSS_UART_tx_complete( ( mss_uart_instance_t * ) pxUART ) == pdFALSE )
+	if( xBufferLength > 0 )
 	{
-		vTaskDelay( xVeryShortDelay );
+		MSS_UART_irq_tx( ( mss_uart_instance_t * ) pxUART, pcBuffer, xBufferLength );
+
+		/* Ensure any previous transmissions have completed.  The default UART
+		interrupt does not provide an event based method of	signally the end of a Tx
+		- this is therefore a crude poll of the Tx end status.  Replacing the
+		default UART handler with one that 'gives' a semaphore when the Tx is
+		complete would allow this poll loop to be replaced by a simple semaphore
+		block. */
+		while( MSS_UART_tx_complete( ( mss_uart_instance_t * ) pxUART ) == pdFALSE )
+		{
+			vTaskDelay( xVeryShortDelay );
+		}
 	}
 }
 /*-----------------------------------------------------------*/