tree 157571907b25404c9d621fc23147f31dec4f31d4
parent 698ef88da4160fa4faa2e6fc674950543b62db07
author Pirmin Vogel <vogelpi@lowrisc.org> 1631812299 +0200
committer Pirmin Vogel <vogelpi@lowrisc.org> 1632131083 +0200

[sca] Optimize sha3_serial for lower noise, return digest via UART

This commit contains the following changes to the sha3_serial
SCA application:
- Instead of busy waiting until KMAC has finished, Ibex is put to sleep
  while KMAC is busy and the timer is used to wakeup Ibex. This
  significantly reduces noise.
- The dedicated FPGA SCA mode of KMAC is used that allows for first
  configuring the unit and providing the message without KMAC starting
  the processing. In a second step, Ibex can then provide the START
  and PROCESS commands which triggers the actual KMAC operation. This
  greatly reduces 1) the number of samples that need to be captured,
  2) the noise in the captured traces, and 3) the amount of processing.
  As this mode is only supported on FPGA but not by the final hardware,
  and thus DIF doesn't support it either, this commit adds the required
  software functions (inspired by the real DIF).
- KMAC is configured to produce a non-zero length digest. The digest
  is read out and returned to the host via UART. Using a Python model
  on the host, this allows verifying KMAC operation during capture.

Signed-off-by: Pirmin Vogel <vogelpi@lowrisc.org>