The MAX_BYTES_PER_BURST option allows to configure the maximum bytes that
are part of a burst. This can be an arbitrary value.
At the same time there is a limit of how many bytes can be supported by the
memory buses. A AXI3 interface supports a maximum of 16 beats per burst
and a AXI4 interface supports a maximum of 256 beats per burst.
At the moment the it is possible to specify a MAX_BYTES_PER_BURST value
that exceeds what can be supported by the AXI memory-mapped bus. If that is
the case undefined behavior will occur and the DMAC will function
incorrectly.
To avoid this make sure that the MAX_BYTES_PER_BURST value does not exceed
the maximum that can be supported by the interfaces.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When a mapping has multiple address segments we need to consider all of
them to calculate the required address width.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The address width needs to be large enough to be able to address the
largest possible address. This means the in addition to the address segment
range the specified offset also needs to be considered to calculate the
address width.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently the AXI address width of the DMA is always 32-bit. But not all
address spaces are so large that they require 32-bit to address all memory.
Extract the size of the address space that the DMA is connected too and
configure reduce the address size to the minimum required to address the
full address space.
This slightly reduces utilization.
If no mapped address space can be found the default of 32 bits is used for
the address.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Add validation values for the different configuration parameters. This
enables the tools to check whether the configured value is valid and avoids
accidental misconfiguration.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Configure the maximum burst size as well as the maximum number of active
requests on the AXI master interfaces according to the core configuration.
This allows connected slaves to know what kind of requests to expect and
allows them to configure themselves accordingly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The axi_dmac core generates requests which are both AXI3 and AXI4
compliant. This means it is possible to connect it to both a AXI3 or AXI4
slave port without needing a AXI protocol converter. Unfortunately it is
not possible to declare a port as both AXI3 and AXI4 compliant, so the core
has the C_DMA_AXI_PROTCOL_SRC and C_DMA_AXI_PROTOCOL_DEST parameters, which
allow to configure the protocol type of the corresponding AXI master
interface. Currently the default is always AXI4.
But when being used on ZYNQ it is most likely that the AXI master interface
of the DMAC core ends up being connected to the AXI3, so change the default
to AXI3 if the core is instantiated in a ZYNQ design.
The default can still be overwritten by explicitly setting the
configuration property.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Add support for querying the clock domains of the clock pins for the
axi_dmac controller. This allows the core to automatically figure out
whether its different parts run in different clock domains or not and setup
the configuration parameters accordingly.
Being able to auto-detect those configuration parameters makes the core
easier to use and also avoids accidental misconfiguration.
It is still possible to automatically overwrite the configuration
parameters by hand if necessary.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen
Istvan Csomortani