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

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change. ( 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.

If the initial timestamp is later than some other timestamps this
messes up the timestamps 'cbmem -t' reports as it thinks they are a
result from a timestamp overflow (reporting that it took 100k years to
boot).

TEST: The ocp/deltalake boots within the span of a lifetime.

Change-Id: I4ba15decec22cd473e63149ec399d82c5e3fd214
Signed-off-by: Arthur Heymans 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47738
Tested-by: build bot (Jenkins) 
Reviewed-by: Angel Pons 
---
M src/soc/intel/xeon_sp/bootblock.c
1 file changed, 14 insertions(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Angel Pons: Looks good to me, approved

diff --git a/src/soc/intel/xeon_sp/bootblock.c b/src/soc/intel/xeon_sp/bootblock.c
index 5adda44..baf5ab5 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();