DMA_Interface

touchgfx/hal/DMA.hpp

DMA_Interface provides basic functionality and structure for processing "blit" operations using DMA.

Inherited by: NoDMA

Public Functions

virtual void	addToQueue(const BlitOp & op)
	Inserts a BlitOp for processing.
virtual void	flush()
	This function blocks until all DMA transfers in the queue have been completed.
bool	getAllowed() const
	Gets whether a DMA operation is allowed to begin.
virtual BlitOperations	getBlitCaps() =0
	Gets the blit capabilities of this DMA.
virtual DMAType	getDMAType()
	Function for obtaining the DMA type of the concrete DMA_Interface implementation.
virtual void	initialize()
	Perform initialization.
uint8_t	isDmaQueueEmpty()
	Query if the DMA queue is empty.
uint8_t	isDmaQueueFull()
	Query if the DMA queue is full.
bool	isDMARunning()
	Query if the DMA is running.
void	setAllowed(bool allowed)
	Sets whether or not a DMA operation is allowed to begin.
virtual void	signalDMAInterrupt() =0
	This function is called automatically by the framework when a DMA interrupt has been received.
virtual void	start()
	Signals that DMA transfers can start.
virtual	~DMA_Interface()
	Finalizes an instance of the DMA_Interface class.

Protected Functions

virtual void	disableAlpha()
	Configures blit-op hardware for solid operation (no alpha-blending)
	DMA_Interface(DMA_Queue & dmaQueue)
	Constructs a DMA Interface object.
virtual void	enableAlpha(uint8_t alpha)
	Configures blit-op hardware for alpha-blending.
virtual void	enableCopyWithTransparentPixels(uint8_t alpha)
	Configures blit-op hardware for alpha-blending while simultaneously skipping transparent pixels.
virtual void	execute()
	Performs a queued blit-op.
virtual void	executeCompleted()
	To be called when blit-op has been performed.
virtual void	seedExecution()
	Called when elements are added to the DMA-queue.
virtual void	setupDataCopy(const BlitOp & blitOp) =0
	Configures blit-op hardware for a 2D copy as specified by blitOp.
virtual void	setupDataFill(const BlitOp & blitOp) =0
	Configures blit-op hardware for a 2D fill as specified by blitOp.
virtual void	waitForFrameBufferSemaphore()
	Waits until framebuffer semaphore is available (i.e.

Protected Attributes

bool	isAllowed
	true if DMA transfers are currently allowed.
bool	isRunning
	true if a DMA transfer is currently ongoing.
DMA_Queue &	queue
	Reference to the DMA queue.

Public Functions Documentation

addToQueue

virtual void addToQueue	(	const BlitOp &	op	)

Inserts a BlitOp for processing.

This also potentially starts the DMA controller, if not already running.

Parameters:

op	The operation to add.

flush

virtual void flush	(			)

This function blocks until all DMA transfers in the queue have been completed.

Reimplemented by: touchgfx::NoDMA::flush

getAllowed

bool getAllowed	(			)	const

Gets whether a DMA operation is allowed to begin.

Used in single-buffering to avoid changing the framebuffer while display is being updated.

Returns:

true if DMA is allowed to start, false if not.

getBlitCaps

virtual BlitOperations getBlitCaps	(			)	=0

Gets the blit capabilities of this DMA.

Returns:

The blit operations supported by this DMA implementation.

Reimplemented by: touchgfx::NoDMA::getBlitCaps

getDMAType

virtual DMAType getDMAType	(			)

Function for obtaining the DMA type of the concrete DMA_Interface implementation.

As default, will return DMA_TYPE_GENERIC type value.

Returns:

a DMAType value of the concrete DMA_Interface implementation.

initialize

virtual void initialize	(			)

Perform initialization.

Does nothing in this base class.

isDmaQueueEmpty

uint8_t isDmaQueueEmpty	(			)

Query if the DMA queue is empty.

Returns:

1 if DMA queue is empty, else 0.

isDmaQueueFull

uint8_t isDmaQueueFull	(			)

Query if the DMA queue is full.

Returns:

1 if DMA queue is full, else 0.

isDMARunning

bool isDMARunning	(			)

Query if the DMA is running.

Returns:

true if a DMA operation is currently in progress.

setAllowed

void setAllowed	(	bool	allowed	)

Sets whether or not a DMA operation is allowed to begin.

Used in single-buffering to avoid changing the framebuffer while display is being updated.

Parameters:

allowed	true if DMA transfers are allowed.

signalDMAInterrupt

virtual void signalDMAInterrupt	(			)	=0

This function is called automatically by the framework when a DMA interrupt has been received.

This function is called automatically by the framework when a DMA interrupt has been received.

Reimplemented by: touchgfx::NoDMA::signalDMAInterrupt

start

virtual void start	(			)

Signals that DMA transfers can start.

If any elements are in the queue, start it.

~DMA_Interface

virtual ~DMA_Interface	(			)

Finalizes an instance of the DMA_Interface class.

Protected Functions Documentation

disableAlpha

virtual void disableAlpha	(			)

Configures blit-op hardware for solid operation (no alpha-blending)

DMA_Interface

DMA_Interface	(	DMA_Queue &	dmaQueue	)

Constructs a DMA Interface object.

Parameters:

dmaQueue	Reference to the queue of DMA operations.

enableAlpha

virtual void enableAlpha	(	uint8_t	alpha	)

Configures blit-op hardware for alpha-blending.

Parameters:

alpha	The alpha-blending value to apply.

enableCopyWithTransparentPixels

virtual void enableCopyWithTransparentPixels	(	uint8_t	alpha	)

Configures blit-op hardware for alpha-blending while simultaneously skipping transparent pixels.

Parameters:

alpha	The alpha-blending value to apply.

execute

virtual void execute	(			)

Performs a queued blit-op.

executeCompleted

virtual void executeCompleted	(			)

To be called when blit-op has been performed.

seedExecution

virtual void seedExecution	(			)

Called when elements are added to the DMA-queue.

Note

The framebuffer must be locked before this method returns if the DMA-queue is non- empty.

setupDataCopy

virtual void setupDataCopy	(	const BlitOp &	blitOp	)

Configures blit-op hardware for a 2D copy as specified by blitOp.

Parameters:

blitOp	The operation to execute.

Reimplemented by: touchgfx::NoDMA::setupDataCopy

setupDataFill

virtual void setupDataFill	(	const BlitOp &	blitOp	)

Configures blit-op hardware for a 2D fill as specified by blitOp.

Parameters:

blitOp	The operation to execute.

Reimplemented by: touchgfx::NoDMA::setupDataFill

waitForFrameBufferSemaphore

virtual void waitForFrameBufferSemaphore	(			)

Waits until framebuffer semaphore is available (i.e.

neither DMA or application is accessing the framebuffer).

Protected Attributes Documentation

isAllowed

bool isAllowed

true if DMA transfers are currently allowed.

isRunning

bool isRunning

true if a DMA transfer is currently ongoing.

queue

DMA_Queue & queue

Reference to the DMA queue.