The debug register logic for the DMA take up a fair amount of resources.
Disabling them frees up space in the FPGA and also helps a bit with power.
Since those registers are mainly useful in development and not so much in
production the change shouldn't have any visible external effects.
It is possible to re-enable the debug registers by setting DEBUG_BUILD=1.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The global reset signals are only asserted for a short moment during system
startup and deasserted during normal operation, which is the case we care
about for power analysis. Giving them a static switching probability
indicating that they are always de-asserted will yield better results for
power analysis.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
At the moment the register map fabric and DMA system memory side are
clocked by the 100MHz sys_cpu_clk. While this works fine that is a lot
faster than the clock has to run. There are only a few 100 register map
accesses per seconds at most and they are not on timing critical paths. The
penalty from clocking them at a lower rate is negligible for the overall
system performance.
The maximum clock rate for the DMAs is determined by the throughput
requirements. This is 200 Mbytes/s for the logic analyzer, pattern
generator and each of the DAC DMAs and 400 Mbytes/s for the ADC DMA.
The DMA datapath width is 64-bit so the required clock rates are 25MHz and
50MHz respectively. Some headroom is required to accommodate for occasional
bubble cycles on the data bus and the difference in reference clocks for
the converter and processing system.
The sys_cpu_clk is reduced to 27.8MHz which is fast enough for all but the
ADC DMA. For the ADC DMA a new clock domain running at 55.6 MHz is
introduced.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The MMCM generating the logic analyzer clock unfortunately consumes a
disproportionately large amount of power compared to the rest of the
design.
Replace it by sourcing the logic analyzer clock from one of the Zynq FCLKs.
The IO PLL is running anyway so the power requirement is much lower.
For the time being this means we loose the ability to source the clock from
an external pin. But that feature is not supported by software at the
moment anyway. We'll bring it eventually when required.
This changes reduces power consumption by roughly 100mW.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Use the new axi_rd_wr_combiner module to ... the read and write DMA
interfaces into a single interface. This allows the AXI interconnect
completely optimize itself away and reduce the overall resource utilization
of the project.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Adrian Costina
Lars-Peter Clausen