axi_dmac: Use AXI3 for DMAC in Intel projects

The buffers inside the interconnect are sized based on maximum burst sizes
the masters can produce.
For AXI4 the max burst size is 128 but for these projects for the
default burst size of 128 bytes the DMACs are creating only burst of 8 or
16 beats depending on the bus width (128bits and 64 bits respectively).

These burst sizes can fit in the AXI3 protocol where the max burst
length is 16. Therefore the interconnect will be reduced.

The observed reduction is around 4 Mb of block RAM per project.
Another benefit is a better timing closure,
since these buffers reside in the DDR3 clock domain.
main
Laszlo Nagy 2018-08-20 08:55:08 +01:00 committed by Laszlo Nagy
parent 2293374307
commit cff06bd779
1 changed files with 1 additions and 1 deletions

View File

@ -91,7 +91,7 @@ foreach {suffix group} { \
{ "0:Memory-Mapped AXI" "1:Streaming AXI" "2:FIFO Interface" }
set_parameter_property DMA_TYPE_$suffix GROUP $group
add_parameter DMA_AXI_PROTOCOL_$suffix INTEGER 0
add_parameter DMA_AXI_PROTOCOL_$suffix INTEGER 1
set_parameter_property DMA_AXI_PROTOCOL_$suffix DISPLAY_NAME "AXI Protocol"
set_parameter_property DMA_AXI_PROTOCOL_$suffix HDL_PARAMETER true
set_parameter_property DMA_AXI_PROTOCOL_$suffix ALLOWED_RANGES { "0:AXI4" "1:AXI3" }