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soc/intel/meteorlake: Send CSE EOP Async CMD early 

This patch sends the CSE EOP command asynchronous implementation early
as part of `soc_init_pre_device`.

Without this patch the duration between asynchronous CSE EOP send and
receive commands is not ample which causes idle delay while waiting
for EOP response.

The goal of the CSE async implementation is to avoid idle delay while
capturing the response from CSE EOP cmd. This patch helps to create
ample duration between CSE EOP command being sent and response being
captured.

TEST=Able to boot google/rex sku to ChromeOS and observed ~100ms of
boot time savings (across warm and cold reset scenarios)

Change-Id: I91ed38edbd5a31d61d4888e1466169a3494d635a
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74561
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Tarun Tuli <taruntuli@google.com>
This commit is contained in:
Subrata Banik 2023-04-19 18:30:53 +05:30 committed by Felix Held
parent 65b54c4f9a
commit ad42d9c22b
1 changed files with 17 additions and 0 deletions
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17
src/soc/intel/meteorlake/chip.c
View File

@ -7,6 +7,7 @@
#include <gpio.h>
#include <intelblocks/acpi.h>
#include <intelblocks/cfg.h>
#include <intelblocks/cse.h>
#include <intelblocks/irq.h>
#include <intelblocks/itss.h>
#include <intelblocks/p2sb.h>
@ -151,6 +152,22 @@ void soc_init_pre_device(void *chip_info)
/* Swap enabled PCI ports in device tree if needed. */
pcie_rp_update_devicetree(get_pcie_rp_table());
/*
* Earlier when coreboot used to send EOP at late as possible caused
* issue of delayed response from CSE since CSE was busy loading payload.
* To resolve the issue, EOP should be sent earlier than current sequence
* in the boot sequence at BS_DEV_INIT.
*
* Intel CSE team recommends to send EOP close to FW init (between FSP-S
* exit and current boot sequence) to reduce message response time from
* CSE hence moving sending EOP to earlier stage.
*/
if (CONFIG(SOC_INTEL_CSE_SEND_EOP_EARLY) ||
CONFIG(SOC_INTEL_CSE_SEND_EOP_ASYNC)) {
printk(BIOS_INFO, "Sending EOP early from SoC\n");
cse_send_end_of_post();
}
}
static void cpu_fill_ssdt(const struct device *dev)