commit 822f23f438199b9a67fb5b92c9cd94cd7306c28a
author June Tate-Gans <jtgans@google.com> Mon Dec 04 18:33:41 2023 +0000
committer June Tate-Gans <jtgans@google.com> Tue Dec 05 14:34:10 2023 +0000
tree 5bf14bf0b105edd8569e358f2e33f03949bf6135
parent c6a976c185595cac3cfadf81e64a17e4dbf2b678

i2s: Add functionality for a loopback sanity test

This simply makes the peripheral initiate record and playback at the
same time, while also shoveling bytes between both FIFOs to write to
disk. In essence, this does a round-trip through the peripheral code,
and should produce a 1:1 matching output on disk from the input file.
Unfortunately, there's no easy way to detect when the recording audio
data has run out, so it's on the user to stop it by disabling the
loopback bit in the control register. In short, to run this sanity
check, do the following:

  1. Set the input and output files in the Renode configuration script.
  2. Start the simulation
  3. Telnet to the Renode console
  4. Run `i2s0 WriteDoubleWord 0x0c 4`
  5. Wait a while.
  6. Run `i2s0 WriteDoubleWord 0x0c 0` or quit Renode.

At this point, the output file should contain the same data as what
was in the input file. Since we can't determine when the file is out
of bytes to read, it may end up zero padded.

Change-Id: I79eb3f017cea3dc415305372e5670789eb329266