This function will be used to generate some entropy using the
Clock Recovery System.
BRANCH=none
BUG=b:38486828
TEST=make BOARD=hammer -j tests
./util/flash_ec --board=hammer --image=build/hammer/test-entropy.bin
EC console: runtest
TEST=Test fails when no USB connection is active
TEST=Test passes when USB connection is active
TEST=Pasting the values into:
tr ';' '\n' | awk 'BEGIN { e = 0; tot=16384.0 }
{ p = $1/tot; if (p > 0) { e -= p*log(p)/log(2) } }
END { print e }'
shows an entropy > 4 bits per sample.
Change-Id: I2363c7bce42c72c33ef0bf3f099d709ee9c13d13
Reviewed-on: https://chromium-review.googlesource.com/518608
Commit-Ready: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
