[coreboot-gerrit] Change in coreboot[master]: soc/intel/xeon_sp: Work around FSP-T not respecting its own API

[Arthur Heymans (Code Review)]

Arthur Heymans has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/47738 )

Change subject: soc/intel/xeon_sp: Work around FSP-T not respecting its own API
......................................................................

soc/intel/xeon_sp: Work around FSP-T not respecting its own API

The CPX FSP-T does not respect the FSP2.x spec and uses registers where
coreboot has its initial timestamp stored.

Change-Id: I4ba15decec22cd473e63149ec399d82c5e3fd214
Signed-off-by: Arthur Heymans 
---
M src/soc/intel/xeon_sp/bootblock.c
1 file changed, 14 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/38/47738/1

diff --git a/src/soc/intel/xeon_sp/bootblock.c b/src/soc/intel/xeon_sp/bootblock.c
index 5adda44..5524c66 100644
--- a/src/soc/intel/xeon_sp/bootblock.c
+++ b/src/soc/intel/xeon_sp/bootblock.c
@@ -33,11 +33,20 @@
    .UpdTerminator = 0x55AA,
 };

+static uint64_t assembly_timestamp;
+static uint64_t bootblock_timestamp;
+
 asmlinkage void bootblock_c_entry(uint64_t base_timestamp)
 {
+	/*
+	 * FSP-T does not respect its own API and trashes registers
+	 * coreboot uses to store its initial timestamp.
+	 */
+	assembly_timestamp = base_timestamp;
+	bootblock_timestamp = timestamp_get();
    fast_spi_cache_bios_region();

-	bootblock_main_with_basetime(base_timestamp);
+	bootblock_main_with_basetime(MIN(assembly_timestamp, bootblock_timestamp));
 }

void bootblock_soc_early_init(void)
@@ -55,6 +64,10 @@
 {
    if (CONFIG(BOOTBLOCK_CONSOLE))
    	printk(BIOS_DEBUG, "FSP TempRamInit successful...\n");
+
+	if (assembly_timestamp < bootblock_timestamp)
+		printk(BIOS_WARNING, "Invalid initial timestamp detected\n");
+
    if (CONFIG(FSP_CAR))
    	report_fspt_output();
    bootblock_pch_init();