g: fix flaky timeout check for spi transfer.

Typically this routine runs on low priority hook task.
A pre-emption by a higher priority task might be mistaken for timeout.
Double check the transfer done status after the timeout time has passed.

Also clear the TXDONE status before starting a fresh transaction to make sure
we wait for the current transaction to complete; an errand TXDONE status
at start of the transaction will pre-empt waiting for the current transaction
and return stale data.

BRANCH=none
TEST=mn50 stress test fails within minutes vs. now stable.
	Main test component is higher priority console task
	that does intermittent compute during usb-spi transfers.
Change-Id: Ide4390e42d3957bc45eea8160617a52dd31ed866
Reviewed-on: https://chromium-review.googlesource.com/849662
Commit-Ready: Marius Schilder <mschilder@chromium.org>
Tested-by: Marius Schilder <mschilder@chromium.org>
Reviewed-by: Marius Schilder <mschilder@chromium.org>
Reviewed-by: Nagendra Modadugu <ngm@google.com>
Reviewed-by: Nick Sanders <nsanders@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

0 files changed, 0 insertions, 0 deletions