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I'd like you to reexamine a change. Please visit
https://review.coreboot.org/c/coreboot/+/62272
to look at the new patch set (#6).
Change subject: soc/intel/adl: Send EOP early in the boot sequence ......................................................................
soc/intel/adl: Send EOP early in the boot sequence
As part of boot time optimization, one of the culprit was CSE where response to End Of Post (EOP) command used to take ~60ms. Earlier patch was pushed to delay the EOP to reduce response time to ~5-7 ms. During this stage overall platform boot time was ~1.15 seconds.
Once boot time was optimized to ~ 1 seconds, CSE EOP time again increased to ~80 ms since coreboot used to send EOP at the time where CSE was busy. This created some back and forth moving of sending EOP command function within coreboot sequence. Upon debugging using traces, it was found that coreboot used to send EOP late where CSE was busy loading other IP payload, so it might take more time to respond.
In order to avoid delayed response, coreboot has to send EOP in stage when CSE is done with firmware init and it will be ready to serve EOP as soon as possible. This also aligns with previous flow where FSP used to send EOP once silicon init is done and coreboot used to rely on FSP to send this message.
Moving EOP to earlier stage (From SoC) meets the requirement and CSE EOP time reduces from ~60 ms to ~20 ms on Brya board.
Note that once SoC code sends EOP, coreboot common code won't send it again since common code already has check in case EOP is sent earlier.
BUG=b:211085685 BRANCH=None TEST=Tested on Brya system before and after the changes. Observed ~40ms savings in boot time.
Change-Id: I9401d5e36ad43cdc0dfe947aabc82528d824df9b Signed-off-by: MAULIK V VAGHELA maulik.v.vaghela@intel.com --- M src/soc/intel/alderlake/Kconfig M src/soc/intel/alderlake/chip.c 2 files changed, 13 insertions(+), 0 deletions(-)
git pull ssh://review.coreboot.org:29418/coreboot refs/changes/72/62272/6