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6ecda4b0f1
If the AP is suspended, it consumes little enough power that just
shutting its rails off doesn't cause it to reset to a known state.
This caused a problem where suspending the AP then rebooting the EC
would wedge the system; the EC would think the AP was on (since
XPSHOLD was asserted), but wouldn't be able to figure out how to turn
it back off. Silego reset wouldn't help, because that again just
reset the EC. Even setting PMIC_RESET to brown out the system
wouldn't drop power for long enough.
Simply pulsing AP_RESET_L low for 1 ms at EC boot (when not sysjump)
or AP force-shutdown forces the AP into a good state.
BUG=chrome-os-partner:22233
BRANCH=pit
TEST=from root shell, 'powerd_dbus_suspend'
from ec console 'reboot' - or just power+refresh
system should power on normally
Change-Id: I65f1239b5f6766f1c093c3064bce323df4acaf7d
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/167355
Reviewed-by: Doug Anderson <dianders@chromium.org>
Commit-Queue: Doug Anderson <dianders@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.