diff options
| author | Kyösti Mälkki <kyosti.malkki@gmail.com> | 2018-06-19 17:53:50 +0300 |
|---|---|---|
| committer | Kyösti Mälkki <kyosti.malkki@gmail.com> | 2018-06-20 19:00:07 +0000 |
| commit | 371e7d95aa640b4c815e71d2448f4c9b26c104bf (patch) | |
| tree | 236134b147718b07ba45f571657704c4da60c9a1 | |
| parent | 4d991550b3a38346071da9dbdc0e7e96a6076082 (diff) | |
nb/intel/e7505: Leave ROM as un-cacheable in postcar
Collected timestamps indicate LZMA decompression of ramstage
is 4x slower when ROM is marked WP-cacheable, in contrast to
having ROM as US. A simple copy WP->WB with uncompressed
ramstage also appeared to be twice as slow as UC->WB copy.
It should be noted that if POSTCAR_STAGE was removed from build,
un-lzma takes 130 seconds instead of 45 milliseconds.
Change-Id: I2cf995395ef2d303ad0bc044dbfa160990a705d0
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/27164
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
| -rw-r--r-- | src/northbridge/intel/e7505/memmap.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/src/northbridge/intel/e7505/memmap.c b/src/northbridge/intel/e7505/memmap.c index 48527fdd96..1b86012907 100644 --- a/src/northbridge/intel/e7505/memmap.c +++ b/src/northbridge/intel/e7505/memmap.c @@ -48,9 +48,12 @@ void platform_enter_postcar(void) if (postcar_frame_init(&pcf, ROMSTAGE_RAM_STACK_SIZE)) die("Unable to initialize postcar frame.\n"); - /* Cache the ROM as WP just below 4GiB. */ - postcar_frame_add_mtrr(&pcf, CACHE_ROM_BASE, CACHE_ROM_SIZE, - MTRR_TYPE_WRPROT); + /* + * Choose to NOT set ROM as WP cacheable here. + * Timestamps indicate the CPU this northbridge code is + * connected to, performs better for memcpy() and un-lzma + * operations when source is left as UC. + */ /* Cache RAM as WB from 0 -> CACHE_TMP_RAMTOP. */ postcar_frame_add_mtrr(&pcf, 0, CACHE_TMP_RAMTOP, MTRR_TYPE_WRBACK); |