Support for Alchitry Au platform

[BradWalker]

Add Servant support for Alchitry Au platform.

Testing

$ fusesoc core show servant
CORE INFO
Name:        ::servant:1.2.1
Description: <No description>
Core root:   fusesoc_libraries/serv
Core file:   servant.core
Targets:
alchitry_au         : Open-hardware Alchitry AU FPGA board
. . .
$

Build bistream

fusesoc run --target=alchitry_au servant --uart_baudrate=57600 --memfile ./fusesoc_libraries/serv/sw/zephyr_hello.hex

. . .
Creating bitstream...
Writing bitstream ./servix.bit...
Writing bitstream ./servix.bin...

Bitstream generation completed
INFO: [Common 17-206] Exiting Vivado at Fri Jun 14 16:49:54 2024...
$

Test bitstream

$ sudo picocom /dev/ttyUSB1 --baud=57600
picocom v3.1
Terminal ready
***** Booting Zephyr OS zephyr-v1.14.1-4-gc7c2d62513fe *****
Hello World! service

Resources used

+----------------------------+------+-------+------------+-----------+-------+
|          Site Type         | Used | Fixed | Prohibited | Available | Util% |
+----------------------------+------+-------+------------+-----------+-------+
| Slice LUTs                 |  244 |     0 |          0 |     20800 |  1.17 |
|   LUT as Logic             |  243 |     0 |          0 |     20800 |  1.17 |
|   LUT as Memory            |    1 |     0 |          0 |      9600 |  0.01 |
|     LUT as Distributed RAM |    0 |     0 |            |           |       |
|     LUT as Shift Register  |    1 |     0 |            |           |       |
| Slice Registers            |  238 |     0 |          0 |     41600 |  0.57 |
|   Register as Flip Flop    |  238 |     0 |          0 |     41600 |  0.57 |
|   Register as Latch        |    0 |     0 |          0 |     41600 |  0.00 |
| F7 Muxes                   |    3 |     0 |          0 |     16300 |  0.02 |
| F8 Muxes                   |    0 |     0 |          0 |      8150 |  0.00 |
+----------------------------+------+-------+------------+-----------+-------+

[olofk]

That looks great! Thank you for your contributions. Picked and pushed