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828c1a384a
Implementation of the physical layer for USB Power Delivery communication using the STM32 chip. Signed-off-by: Vincent Palatin <vpalatin@chromium.org> BRANCH=none BUG=none TEST=none Change-Id: I2a4adeef572b97a284bf52ab9d14d23246c56d18 Reviewed-on: https://chromium-review.googlesource.com/189867 Tested-by: Vincent Palatin <vpalatin@chromium.org> Reviewed-by: Randall Spangler <rspangler@chromium.org> Commit-Queue: Vincent Palatin <vpalatin@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.