bmpblock v1.2 - render HWID inside vboot_reference

The vboot_api.h doesn't require the BIOS display the ASCII HWID in
a graphical form (ARM U-Boot doesn't know how), so we have to do it
ourselves. This change makes that possible.

Summary of changes:
* bmpblk_font.h defines a structure to map ASCII chars to BMPs
* bmpblk_font utility generates that font structure
* bmpblock format is bumped to version 1.2
  - YAML file specifies font to use for $HWID
  - make_default_yaml updated to emit the new format
  - README updated to describe the difference

BUG=chromium-os:18631
TEST=manual

I've tested this on ARM, like so:

Inside the chroot, build a U-Boot that uses it:

  emerge-tegra2_kaen vboot_reference vboot_reference-firmware
  emerge-tegra2_kaen tegra-bct tegra2-public-firmware-fdts \
                     chromeos-u-boot chromeos-bootimage

Outside chroot, but in src/platform/vboot_reference:

  make
  <copy ./build/utility/bmpblk_font and ./build/utility/bmpblk_utility to
    somewhere in your $PATH>
  make clean

  cd scripts/newbitmaps/fonts
  bmpblk_font --outfile ../images/hwid_fonts.bin outdir/*

  cd scripts/newbitmaps/images
  make arm
  cd out_arm
  <edit DEFAULT.yaml>
  bmpblk_utility -z 2 -c DEFAULT.yaml arm_bmpblock.bin

  <use gbb_utility to replace the bitmaps in the U-Boot image, boot it>

The HWID string is displayed.

Change-Id: I782004a0f30c57fa1f3bb246e8c59a02c5e9f561
Reviewed-on: http://gerrit.chromium.org/gerrit/6544
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Bill Richardson <wfrichar@chromium.org>
17 files changed