tree 689f9bf60da510dc661e266e977e24f3291fbda4
parent ea14a6e1838ea01103d88cbc9ccc2eb7e57483dd
author Vadim Bendebury <vbendeb@chromium.org> 1434153895 -0700
committer ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> 1435187618 +0000

trunks: ftdi: implement SendAndWait

To send a command to the TPM FIFO the master is supposed to first
inform the TPM about the incoming command. The spec states that the
TPM *may* reply to this with setting the .Expect bit in the status
register. The Infineon device this code was tested with does not set
this bit, so its polling is not implemented.

TPM status register also allows to check when the device has finished
processing the command and the response is ready in the FIFO register.

This patch adds the code which follows this protocol: sends a command
to the TPM and then expects the response by polling the status
register. A method is being added to poll the status register for a
certain state, and a bug in ReadTpmSts() is fixed.

BUG=chromium:498861

TEST=after connecting the TPM2 setup using the USB-FTDI-SPI dongle run
     the following commands inside chroot:

  $ sudo emerge trunks
    # suppressed portage output here....
  $ sudo trunks_client --ftdi --startup
  Connected to device vid:did:rid of 15d1:001b:10
  $

Change-Id: I315f2b873d87d6c4730aa0d3e13ebaa124ce58ff
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/277318
Reviewed-by: Utkarsh Sanghi <usanghi@chromium.org>
Commit-Queue: Bill Richardson <wfrichar@chromium.org>
Trybot-Ready: Bill Richardson <wfrichar@chromium.org>