The read and write interfaces of a AXI bus are independent other than that
they use the same clock. Yet when connecting a single read-only and a
single write-only interface to a Xilinx AXI interconnect it instantiates
arbitration logic between the two interfaces. This is dead logic and
unnecessarily utilizes the FPGAs resources.
Introduce a new helper module that takes a read-only and a write-only AXI
interface and combines them into a single read-write interface. The only
restriction here is that all three interfaces need to use the same clock.
This module is useful for systems which feature a read DMA and a write DMA.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The register read logic is not that complicated that it needs two extra
pipeline stages. It can easily be condensed into a single combinatorial and
still meet timing with large margins.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Disable registers in the register map which are not needed for this core.
This reduces the utilization of the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Not all peripherals use the GPIO register settings, but the registers still
take up a fair amount of space in the register map. Add options to allow to
disable them when not needed. This helps to reduce the utilization for
peripherals where these features are not needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Not all peripherals use the GPIO and START_CODE register settings, but the
registers still take up a fair amount of space in the register map. Add
options to allow to disable them when not needed. This helps to reduce the
utilization for peripherals where these features are not needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Depending on whether the core is configured for AXI4 or AXI3 mode the width
of the awlen/arlen signal is either 8 or 4 bit. At the moment this is only
considered in top-level module and all other modules use 8 bit internally.
This causes warnings about truncated signals in AXI3 mode, to resolve this
forward the width of the signal through the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Declaring local parameters in the module parameter list is not valid
verilog. For some reasons Vivado accepts it nevertheless so the code has
worked so far. But this is not true for other tools, so move the local
parameter definitions inside the module body.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
For experimentation, to solve a constraint scoping issue, split up the
ad_axi_ip_constraint file into separate constraints file, in function
of there parent module.
It seems that in the latest version a constant of "0" is no longer a valid
enablement dependency and "false" has be used instead.
Not setting the enablement dependency correctly results in the AXI port to
be assumed to be read-write rather than just read or write. This will
generate unnecessary logic for example in interconnects to which the DMA
controller is connected.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Adrian Costina
Lars-Peter Clausen
Istvan Csomortani
Rejeesh Kutty
Istvan Csomortani