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2f084199ca
If EC_BL_OVERRIDE is low, backlight will be turned off. To allow AP to
control backlight, set EC_BL_OVERRIDE to high.
BUG=none
BRANCH=nyan
TEST=verified on nyan board 2.0 to see backlight turns on when system
boots up
Change-Id: I04e6052fbef4b17c3f9566c8c5cf691a2710b7b0
Signed-off-by: Yen Lin <yelin@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/177553
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Yung-chieh Lo <yjlou@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.