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1b4c5cf71e
There are a few issues with console output:
1. The EC was returning more bytes than the message's insize. The
reason stems from a refacotring that the set the global
ec_max_insize variables to 'EC_PROTO2_MAX_PARAM_SIZE - 8'.
It really should be EC_PROTO2_MAX_PARAM_SIZE to cover the
maximum packet size returned from the EC.
2. A change was made to handle EAGAIN returning from the EC kernel
driver's ioctl() interface. That change prevented 0 bytes received
from being returned properly.
The first issue occurs because the EC console is always larger than
what the original ec_max_insize was set to. This caused no console
messages to be displayed. The second issue causes the console command
to potentially loop forever because the drain of the EC console is
never indicated because 0 could never be returned.
BUG=chrome-os-partner:21165
BRANCH=falco,peppy
TEST=Built and can now read 'ectool console' output as well
as not including gargabe.
Change-Id: I3114594f0020a5198532aa78ce126f4da6caf09a
Reviewed-on: https://gerrit.chromium.org/gerrit/63445
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Queue: Aaron Durbin <adurbin@chromium.org>
Tested-by: Aaron Durbin <adurbin@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.