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1d2845d2db
This adds space for up to two ALS lux readings to be available to the AP
through the memory-mapped LPC region. If enabled, the values are updated
once a second.
The ALS will be reinitialized at every AP resume, since it's typically
unpowered otherwise. The reported value will be zero when the ALS is off.
BUG=chrome-os-partner:23380
BRANCH=samus
TEST=manual
Boot the AP, then from the EC console run "als" or just monitor the
memory-mapped region directly ("rw 0x40080780" on Samus), while pointing the
sensor at bright and dim areas. The value should change.
Change-Id: I705371fcd57345dc9adae1231ea30c7ff024aaf8
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/176142
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.