Accessing RAM before mmu initialized is time consuming. During mmu
initialization, `mmu_init()` and `mmu_config_range()` write logs to the
console buffer and contribue the extra boot time.
This patch adds a kconfig option to move `mtk_mmu_init()` to
`bootblock_soc_early_init()`. When `EARLY_MMU_INIT` is enabled, mmu is
initialized before `console_init()` ready. So `mmu_init()` and
`mmu_config_range()` won't write logs to the console buffer and save the
boot time.
It saves about 65ms on Geralt with EARLY_MMU_INIT enabled.
Before:
0:1st timestamp 239,841 (0)
11:start of bootblock 239,920 (79)
12:end of bootblock 323,191 (83,271)
After:
0:1st timestamp 239,804 (0)
11:start of bootblock 239,884 (80)
12:end of bootblock 258,846 (18,962)
BUG=b:320381143
TEST=check timestamps in cbmem
Change-Id: I7f4c3c6c836f7276119698c6de362794cf4222a6
Signed-off-by: Yidi Lin <yidilin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79990
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
c68176c14e