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intel/common/block/cse: Add option to send EOP early via SoC 

Earlier while trying to optimize boot time End Of Post (EOP) time kept
increasing (~80 ms) when boot time decreased to around 1 second.
This was because CSE was busy with own firmware loading.

When EOP was moved later in boot stage it again created issue since CSE
got busy with other payload loading for OS boot, so response to EOP
got delayed by ~70-80 ms.

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 BS_DEV_INIT boot state meets this requirement and CSE EOP
time reduces from ~60 ms to ~20 ms on Brya QS board.

Since this setting might vary for each SoC, SoCs can decide when to send
EOP in the boot sequence. This patch adds Kconfig option to send EOP via
SoC

BUG=b:211085685
BRANCH=firmware-brya-14505.B
TEST=Code compilation is fine for Brya board. Boot time test is done
using entire patchset and EOP time is reduced to ~25ms from earlier ~80ms.

Change-Id: I9c7fe6f8f3fadb68310d4a09692f51f82c737c35
Signed-off-by: MAULIK V VAGHELA <maulik.v.vaghela@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60195
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Ronak Kanabar <ronak.kanabar@intel.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
This commit is contained in:
MAULIK V VAGHELA 2021-12-17 17:55:22 +05:30 committed by Felix Held
parent 40ca79714a
commit 61b8f89ce3
1 changed files with 9 additions and 0 deletions
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9
src/soc/intel/common/block/cse/Kconfig
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@ -45,6 +45,15 @@ config SOC_INTEL_COMMON_BLOCK_HECI1_DISABLE_USING_PCR
Use this config for SoC platform prior to CNL PCH (with postboot_sai implemented)
to make `HECI1` device disable using private configuration register (PCR) write.
config SOC_INTEL_CSE_SEND_EOP_EARLY
bool
depends on SOC_INTEL_COMMON_BLOCK_CSE
help
Use this config to send End Of Post (EOP) earlier through SoC code in order to
reduce time required to send EOP and getting CSE response.
In later stages, CSE might be busy and might require more time to process EOP command.
SoC can use this Kconfig to send EOP earlier by itself.
config SOC_INTEL_CSE_LITE_SKU
bool
default n