Xilinx KCU105 User Manual page 102

Table E-1: APIs Provided by the XDMA Driver in Windows
API Prototype
XDMA_HANDLE
XDMARegister(
IN
PREGISTER_DMA_ENGINE
_REQUEST LinkReq,
OUT
PREGISTER_DMA_ENGINE
_RETURN LinkRet
)
PCIe Streaming Data Plane TRD
UG920 (v2017.1) June 01, 2017
Appendix E:
Details
This API is made available
to child drivers present on
the DMA driver's virtual
bus.
It is used by child drivers
to register themselves
with DMA driver for a
particular channel on
DMA.
Only after successful
registration will the child
drivers be able to initiate
I/O transfers on the
channel.
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APIs Provided by the XDMA Driver in Windows
Parameters
PREGISTER_DMA_ENGINE
_REQUEST
DMA Engine Request
provides all the required
information needed by
XDMA driver to validate
the child driver's request
and provide access to the
DMA channel.
It contains the following
information:
1. Channel number
2. Number of queues the
child driver wants the
DMA driver to allocate and
maintain.
(It can be either 2 or 4
depending on the
application's use case.)
3. Number of Buffer
Descriptors in Source,
Destination SGL queues
and the corresponding
Status Queues.
4. Coalesce count for that
channel
5. Direction of the
channel.
6. Function Pointers to be
invoked to intimate
successful completion of
I/O transfers.
PREGISTER_DMA_ENGINE
_RETURN
DMA Engine Return
provides a structure which
contains the following
information:
1. DMA function pointer
for initiating data transfer.
2. DMA function pointer
for cancelling transfers
and doing DMA reset.
Return
XDMA_HANDLE
The handle is a way for
DMA driver to identify the
channel registered with
Child driver.
All function calls to DMA
driver after registration
will have this as its input
argument.
If the DMA Registration is
not successful,
XDMA_HANDLE will be
NULL
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