mirror of
https://github.com/Telecominfraproject/OpenCellular.git
synced 2026-01-10 01:21:49 +00:00
32d073f6c6
We've removed a few constants from the exported header file since the last big sync. Just in case some of them are still in use (coredump, flashrom), let's make it easy to redistribute the header unchanged. We can remove them for real next time. BUG=chromium:251441 BRANCH=none TEST=manual Compile, test, run, etc. This CL just adds back some unused (by the EC) constants that were previously removed, so nothing should change. Change-Id: Ia9889db89a90d56c8154fea1e8c8a483fdcae805 Signed-off-by: Bill Richardson <wfrichar@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/170522 Reviewed-by: Randall Spangler <rspangler@chromium.org>
In the most general case, the flash layout looks something like this: +---------------------+ | Reserved for EC use | +---------------------+ +---------------------+ | Vblock B | +---------------------+ | RW firmware B | +---------------------+ +---------------------+ | Vblock A | +---------------------+ | RW firmware A | +---------------------+ +---------------------+ | FMAP | +---------------------+ | Public root key | +---------------------+ | Read-only firmware | +---------------------+ BIOS firmware (and kernel) put the vblock info at the start of each image where it's easy to find. The Blizzard EC expects the firmware vector table to come first, so we have to put the vblock at the end. This means we have to know where to look for it, but that's built into the FMAP and the RO firmware anyway, so that's not an issue. The RO firmware doesn't need a vblock of course, but it does need some reserved space for vboot-related things. Using SHA256/RSA4096, the vblock is 2468 bytes (0x9a4), while the public root key is 1064 bytes (0x428) and the current FMAP is 644 bytes (0x284). If we reserve 4K at the top of each FW image, that should give us plenty of room for vboot-related stuff.