Merge pull request 32blit#711 from Daft-Freak/fix-flashing

Fix CDC FIFO used getting out of sync
ali1234 · Aug 26, 2021 · c2c1207 · c2c1207
2 parents d9ded2d + 5368ff3
commit c2c1207
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Showing 2 changed files with 3 additions and 11 deletions.
diff --git a/32blit-stm32/Inc/CDCCommandStream.h b/32blit-stm32/Inc/CDCCommandStream.h
@@ -26,7 +26,7 @@ struct CDCFifoElement
 class CDCCommandStream
 {
 public:
-	CDCCommandStream() : m_uFifoReadPos(0), m_uFifoWritePos(0), m_uFifoUsedCount(0)
+	CDCCommandStream() : m_uFifoReadPos(0), m_uFifoWritePos(0)
 	{
 		Init();
 	}
@@ -44,11 +44,6 @@ class CDCCommandStream
 	void						ReleaseFifoWriteBuffer(uint8_t uLen);
 	CDCFifoElement  *GetFifoReadElement(void);
 	void 						ReleaseFifoReadElement(void);
-	bool						IsFifoFull(void)
-	{
-		return m_uFifoUsedCount==CDC_FIFO_BUFFERS;
-	}
-
 
 private:
 	typedef enum { stDetect, stDetectCommandWord, stDispatch, stProcessing, stError } StreamState;
@@ -74,7 +69,6 @@ class CDCCommandStream
 	CDCFifoElement m_fifoElements[CDC_FIFO_BUFFERS];
 	uint8_t				 m_uFifoReadPos;
 	uint8_t				 m_uFifoWritePos;
-	uint8_t				 m_uFifoUsedCount;
 
 	bool					m_bNeedsUSBResume;
 

diff --git a/32blit-stm32/Src/CDCCommandStream.cpp b/32blit-stm32/Src/CDCCommandStream.cpp
@@ -212,7 +212,7 @@ uint32_t CDCCommandStream::GetTimeTaken(void)
 uint8_t	*CDCCommandStream::GetFifoWriteBuffer(void)
 {
 	uint8_t *pData = NULL;
-	if(m_uFifoUsedCount < CDC_FIFO_BUFFERS - 1)
+	if((m_uFifoWritePos + 1) % CDC_FIFO_BUFFERS != m_uFifoReadPos)
 	{
 		pData = m_fifoElements[m_uFifoWritePos].m_data;
 	}
@@ -228,13 +228,12 @@ void	CDCCommandStream::ReleaseFifoWriteBuffer(uint8_t uLen)
 	m_uFifoWritePos++;
 	if(m_uFifoWritePos == CDC_FIFO_BUFFERS)
 		m_uFifoWritePos = 0;
-	m_uFifoUsedCount++;
 }
 
 CDCFifoElement  *CDCCommandStream::GetFifoReadElement(void)
 {
 	CDCFifoElement *pElement = NULL;
-	if(m_uFifoUsedCount)
+	if(m_uFifoReadPos != m_uFifoWritePos)
 		pElement = &m_fifoElements[m_uFifoReadPos];
 	return pElement;
 }
@@ -244,7 +243,6 @@ void CDCCommandStream::ReleaseFifoReadElement(void)
 	m_uFifoReadPos++;
 	if(m_uFifoReadPos == CDC_FIFO_BUFFERS)
 		m_uFifoReadPos = 0;
-	m_uFifoUsedCount--;
 }
 
 // usb host glue