Unit DMA

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Description


To be documented

Constants


To be documented

Type definitions


To be documented

Public variables


To be documented

Function declarations



Initialization functions

procedure DMAInit;
Description: To be documented
Note To be documented


DMA host functions

function DMAHostStart(DMA:PDMAHost):LongWord;
Description: To be documented
Note To be documented


function DMAHostStop(DMA:PDMAHost):LongWord;
Description: To be documented
Note To be documented


function DMAHostReset(DMA:PDMAHost):LongWord;
Description: To be documented
Note To be documented


function DMAHostProperties(DMA:PDMAHost; Properties:PDMAProperties):LongWord;
Description: To be documented
Note To be documented


function DMAHostCreate:PDMAHost;
Description: Create a new DMA entry
Return Pointer to new DMA entry or nil if DMA could not be created


function DMAHostCreateEx(Size:LongWord):PDMAHost;
Description: Create a new DMA entry
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


function DMAHostDestroy(DMA:PDMAHost):LongWord;
Description: Destroy an existing DMA entry
Note To be documented


function DMAHostRegister(DMA:PDMAHost):LongWord;
Description: Register a new DMA in the DMA host table
Note To be documented


function DMAHostDeregister(DMA:PDMAHost):LongWord;
Description: Deregister a DMA from the DMA host table
Note To be documented


function DMAHostFind(DMAId:LongWord):PDMAHost;
Description: To be documented
Note To be documented


function DMAHostEnumerate(Callback:TDMAEnumerate; Data:Pointer):LongWord;
Description: To be documented
Note To be documented


function DMAHostNotification(DMA:PDMAHost; Callback:TDMANotification; Data:Pointer; Notification,Flags:LongWord):LongWord;
Description: To be documented
Note To be documented


DMA data functions

function DMADataCount(Data:PDMAData):LongWord;
Description: Return the total number of data blocks in the linked list
Note To be documented


function DMADataFlags(Data:PDMAData):LongWord;
Description: Return the combined flags of the data blocks in the linked list
Note To be documented


function DMADataMaximum(Data:PDMAData):LongWord;
Description: Return the size of the largest data block in the linked list
Note To be documented


DMA buffer functions

function DMABufferAllocate(DMA:PDMAHost; Size:LongWord):Pointer; inline;
Description: Allocate a data buffer for a DMA request
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


function DMABufferAllocateEx(DMA:PDMAHost; var Size:LongWord):Pointer;
Description: Allocate a data buffer for a DMA request
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


function DMABufferValidate(DMA:PDMAHost; Buffer:Pointer; Size:LongWord):LongWord;
Description: Validate a data buffer for a DMA request against the DMA host requirements
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.


function DMABufferRelease(Buffer:Pointer):LongWord;
Description: Release a data buffer from a DMA request
Data The buffer to be released
Return ERROR_SUCCESS on success or another error code on failure



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