[coreboot-gerrit] Patch merged into coreboot/master: cbfs: Add LZ4 in-place decompression support for pre-RAM stages

[gerrit at coreboot.org]

the following patch was just integrated into master:
commit 09f2921b5dacaf79b391652cecd606be4dd69f50
Author: Julius Werner <jwerner at chromium.org>
Date:   Tue Sep 29 13:51:35 2015 -0700

    cbfs: Add LZ4 in-place decompression support for pre-RAM stages
    
    This patch ports the LZ4 decompression code that debuted in libpayload
    last year to coreboot for use in CBFS stages (upgrading the base
    algorithm to LZ4's dev branch to access the new in-place decompression
    checks). This is especially useful for pre-RAM stages in constrained
    SRAM-based systems, which previously could not be compressed due to
    the size requirements of the LZMA scratchpad and bounce buffer. The
    LZ4 algorithm offers a very lean decompressor function and in-place
    decompression support to achieve roughly the same boot speed gains
    (trading compression ratio for decompression time) with nearly no
    memory overhead.
    
    For now we only activate it for the stages that had previously not been
    compressed at all on non-XIP (read: non-x86) boards. In the future we
    may also consider replacing LZMA completely for certain boards, since
    which algorithm wins out on boot speed depends on board-specific
    parameters (architecture, processor speed, SPI transfer rate, etc.).
    
    BRANCH=None
    BUG=None
    TEST=Built and booted Oak, Jerry, Nyan and Falco. Measured boot time on
    Oak to be about ~20ms faster (cutting load times for affected stages
    almost in half).
    
    Change-Id: Iec256c0e6d585d1b69985461939884a54e3ab900
    Signed-off-by: Julius Werner <jwerner at chromium.org>
    Reviewed-on: https://review.coreboot.org/13638
    Tested-by: build bot (Jenkins)
    Reviewed-by: Aaron Durbin <adurbin at chromium.org>


See https://review.coreboot.org/13638 for details.

-gerrit