Transfer Descriptor Status Word (Status – Offset 1Ch) - 4.1 English

AXI Central Direct Memory Access LogiCORE IP Product Guide (PG034)

Document ID
PG034
Release Date
2022-05-18
Version
4.1 English

This value provides the status to the software application regarding the execution of the Transfer Descriptor by the AXI CDMA. This status word should be zeroed when the transfer descriptor is programmed by the software application. When the AXI CDMA SG Engine has completed execution of the transfer descriptor, the status word is updated and written back to the original status word location in memory by the SG Engine.

Figure 3-9:      Transfer Descriptor Status Word

X-Ref Target - Figure 3-9

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Table 3-9:      Transfer Descriptor Status Word Details

Bits

Field Name

Description

31

Cmplt

Transfer Completed. This indicates to the software application that the CDMA Engine has completed the transfer as described by the associated descriptor. The software application can manipulate any descriptor with the Completed bit set to 1 when in Tail Pointer Mode (currently the only supported mode).

0 = Descriptor not completed

1 = Descriptor completed

If the CDMA SG Engine fetches a descriptor, this bit is set to 1, the descriptor is considered a stale descriptor. An SGIntErr is flagged in the AXI CDMA Status register and the AXI CDMA engine halts with no update to the descriptor. This bit is ignored when AXI CDMA is put in Cyclic mode.

30

DMADecErr

DMA Decode Error. This bit indicates that an AXI decode error was received by the AXI CDMA DataMover. This error occurs if the DataMover issues an address that does not have a mapping assignment to a slave device. This error condition causes the AXI CDMA to halt gracefully.

0 = No CDMA Decode Errors

1 = CDMA Decode Error received. CDMA Engine halts at this descriptor.

29

DMASlvErr

DMA Slave Error. This bit indicates that an AXI slave error response was received by the AXI CDMA DataMover during the AXI transfer (read or write) associated with this descriptor. This error condition causes the AXI CDMA to halt gracefully.

0 = No CDMA Slave Errors

1 = CDMA Slave Error received. CDMA Engine halts at this descriptor.

28

DMAIntErr

DMA Internal Error. This bit indicates that an internal error was encountered by the AXI CDMA DataMover on the data transport channel during the execution of this descriptor. This error can occur if a 0 value BTT (bytes to transfer) is fed to the AXI DataMover or DataMover has an internal processing error. A BTT of 0 only happens if the BTT field in the transfer descriptor CONTROL word is programmed with a value of zero. This error condition causes the AXI CDMA to gracefully halt. The CDMASR.IDLE bit is set to 1 when the CDMA has completed shutdown.

0 = No CDMA Internal Errors

1 = CDMA Internal Error detected. CDMA Engine halts at this descriptor.

27 to 0

Reserved

These bits are reserved and should be set to zero.