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authorJulius Werner <jwerner@chromium.org>2015-09-29 13:51:35 -0700
committerJulius Werner <jwerner@chromium.org>2016-02-22 21:38:37 +0100
commit09f2921b5dacaf79b391652cecd606be4dd69f50 (patch)
tree581236de48a22240cb1b823195a79493f037fb64 /src/Kconfig
parent0e3d7de7410c4ff7c9465261b58524675a0329e2 (diff)
downloadcoreboot-09f2921b5dacaf79b391652cecd606be4dd69f50.tar.xz
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@chromium.org> Reviewed-on: https://review.coreboot.org/13638 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src/Kconfig')
-rw-r--r--src/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/src/Kconfig b/src/Kconfig
index 4cceb141c7..3def65b758 100644
--- a/src/Kconfig
+++ b/src/Kconfig
@@ -156,6 +156,17 @@ config COMPRESS_RAMSTAGE
that decompression might slow down booting if the boot flash
is connected through a slow link (i.e. SPI).
+config COMPRESS_PRERAM_STAGES
+ bool "Compress romstage and verstage with LZ4"
+ default y if !ARCH_X86
+ default n
+ help
+ Compress romstage and (if it exists) verstage with LZ4 to save flash
+ space and speed up boot, since the time for reading the image from SPI
+ (and in the vboot case verifying it) is usually much greater than the
+ time spent decompressing. Doesn't work for XIP stages (assume all
+ ARCH_X86 for now) for obvious reasons.
+
config INCLUDE_CONFIG_FILE
bool "Include the coreboot .config file into the ROM image"
default y