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BUG=chrome-os-partner:25298 BRANCH=rambi TEST=manaully test on Squawks EVT board Signed-off-by: Heng-ruey Hsu <henryhsu@chromium.org> Change-Id: Ifc63dd22607c23719dedb6af8e570da4076ad8ee Original-Change-Id: I932545e0bf0234eb9c3bdc399f5b29c9e4913951 Reviewed-on: https://chromium-review.googlesource.com/183904 Reviewed-by: Randall Spangler <rspangler@chromium.org> Commit-Queue: Heng-ruey Hsu <henryhsu@chromium.org> Tested-by: Heng-ruey Hsu <henryhsu@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/192194 Tested-by: Dave Parker <dparker@chromium.org> Reviewed-by: Heng-ruey Hsu <henryhsu@chromium.org> Commit-Queue: Dave Parker <dparker@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.