hammer: Make keyboard work at firmware screen

First, libpayload expects the keyboard interface index to be 0.

Then, hid_iface_request needs to reply to USB_HID_DT_HID request
with the content of struct usb_hid_descriptor. With current code,
the variable name is generated (and therefore hard to guess), so
we create a new set of macros so that we can use a specific
variable name.

Also, add support for HID Get_Protocol and Set_Protocol, as they
are compulsory for devices supporting boot protocol, even though
those are mostly no-op for now.

Finally, add a note regarding USB HID keyboard boot protocol, to
make sure that we do not accidentally change the report format.

BRANCH=none
BUG=b:36538963
TEST=Keyboard works in FW screen, both trackpad and keyboard
     still work when AP has booted.
TEST=hammer/staff can still be updated (both RO from RW, and RW
     from RO)

Change-Id: Ibea4888385909c9ce3b430464e5805c039d4b9ed
Reviewed-on: https://chromium-review.googlesource.com/505796
Commit-Ready: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

0 files changed, 0 insertions, 0 deletions