Difference between revisions of "Unit DMA"

Revision as of 03:26, 28 July 2016

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 </div></div>
 <br />
+'''DMA transfer functions'''
+<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
+<pre style="border: 0; padding-bottom:0px;">function DMATransferRequest(DMA:PDMAHost; Data:PDMAData; Direction,Peripheral,Flags,Timeout:LongWord):LongWord;</pre>
+<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Perform a DMA transfer request with the supplied data blocks on the supplied host</div>
+<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
+{| class="wikitable" style="font-size: 14px; background: white;"
+|-
+! '''DMA'''
+| The DMA host to execute the request on
+|-
+! '''Data'''
+| A linked list of DMA data blocks for the transfer
+|-
+! '''Direction'''
+| The direction of the DMA request (eg DMA_DIR_MEM_TO_MEM)
+|-
+! '''Peripheral'''
+| The peripheral ID for data request gating (eg DMA_DREQ_ID_NONE)
+|-
+! '''Flags'''
+| Additional flags for this transfer request (eg DMA_REQUEST_FLAG_CYCLIC)
+|-
+! '''Timeout'''
+| Milliseconds to wait for request to complete (INFINITE to wait forever)
+|-
+! '''Note'''
+| An internal callback will be specified and the function will wait for the transfer to complete
+|-
+|}
+</div></div>
+<br />
 Return to [[Unit_Reference|Unit Reference]]

Size	Size in bytes to allocate for new DMA (Including the DMA entry")
Return	Pointer to new DMA entry or nil if DMA could not be created

DMA	The DMA host that the request will be sent to
Size	The size of the data buffer to allocate
Return	The newly allocated buffer or nil on failure

DMA	The DMA host that the request will be sent to
Size	The size of the data buffer to allocate (Updated on return to actual size)
Return	The newly allocated buffer or nil on failure
Note	This differs from DMABufferAllocate in that it updates the size value to reflect the actual size of the buffer allocated which may be required for some uses

DMA	The DMA host that the request will be sent to
Buffer	The data buffer to validate
Size	The size of the data buffer
Return	ERROR_SUCCESS on success or another error code on failure (ERROR_NOT_COMPATIBLE if not compatible with host)
Note	Does not check for cache coherency requirements (Shared, Non Cached) only alignment and size. Buffers used as the source of a DMA request do not neccessarily need to meet alignment and size requirements, however buffers used as a destintation must meet these requirements or the caller must take appropriate actions to prevent undesiraable side effects from cache invalidation.

Data	The buffer to be released
Return	ERROR_SUCCESS on success or another error code on failure

DMA	The DMA host this request will be sent to
Data	A linked list of DMA data blocks for the transfer (Optional)
Callback	The callback function to be called on completion of the request
DriverData	Driver private data for the callback (Optional)
Direction	The direction of the DMA request (eg DMA_DIR_MEM_TO_MEM)
Peripheral	The peripheral ID for data request gating (eg DMA_DREQ_ID_NONE)
Flags	Additional flags for this request (eg DMA_REQUEST_FLAG_CYCLIC)
Return	The newly allocated request or nil on failure

Request	The request to be released
Return	ERROR_SUCCESS on success or another error code on failure

Request	The request to be submitted
Return	ERROR_SUCCESS if completed or another error code on failure
Note	The request will be completed asynchronously by the DMA host and the completion callback will be called when the request has either succeeded or failed

Request	The request to be cancelled
Return	ERROR_SUCCESS if completed or another error code on failure

Request	The DMA request which has completed
Note	DMA host drivers may call this on a worker thread

DMA	The DMA host to execute the request on
Data	A linked list of DMA data blocks for the transfer
Direction	The direction of the DMA request (eg DMA_DIR_MEM_TO_MEM)
Peripheral	The peripheral ID for data request gating (eg DMA_DREQ_ID_NONE)
Flags	Additional flags for this transfer request (eg DMA_REQUEST_FLAG_CYCLIC)
Timeout	Milliseconds to wait for request to complete (INFINITE to wait forever)
Note	An internal callback will be specified and the function will wait for the transfer to complete