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With this, we can more precisely distinguish a video dongle and an USB host. The downside is that old boards with ID_OUT connected instead of CABLE_DET will lose the ability to use a video dongle. BUG=chrome-os-partner:21310 TEST=Plug in USB host in S5 and see it's detected correctly. BRANCH=Spring Change-Id: I26856593a9fc1ef99c60b27aef3a53538e96f482 Original-Change-Id: I1116ac447bbc0b491f88fa38c16ff57501fe0288 Signed-off-by: Vic Yang <victoryang@chromium.org> Reviewed-on: https://gerrit.chromium.org/gerrit/63297 Reviewed-by: Jeremy Thorpe <jeremyt@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org> Reviewed-on: https://gerrit.chromium.org/gerrit/64273
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.