soc/intel/fsp_broadwell_de: Check if memory is 'locked'

Under certain conditions TXT can "lock" memory controller for security
purpose. This manifests itself in IMC's SMbus controller failing all SPD
data read requests.  FSP does not detect error condition and fails boot
with "No memory found" issue.

TEST=tested on OCP monolake in 'locked' state

Change-Id: If4637e4293421794a89037ff107e87794c40114a
Signed-off-by: Andrey Petrov <anpetrov@fb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42710
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Christian Walter <christian.walter@9elements.com>

3 files changed, 17 insertions, 0 deletions

diff --git a/src/soc/intel/fsp_broadwell_de/include/soc/memory.h b/src/soc/intel/fsp_broadwell_de/include/soc/memory.h
index 3bdba2ef56..494ca34da1 100644
--- a/src/soc/intel/fsp_broadwell_de/include/soc/memory.h
+++ b/src/soc/intel/fsp_broadwell_de/include/soc/memory.h
@@ -27,4 +27,8 @@
 
 void save_dimm_info(void);
 
+/* Determine if memory configuration has been locked by TXT */
+bool memory_config_is_locked(void);
+
+
 #endif
diff --git a/src/soc/intel/fsp_broadwell_de/include/soc/msr.h b/src/soc/intel/fsp_broadwell_de/include/soc/msr.h
index f9fdffb2bf..2bbcf23687 100644
--- a/src/soc/intel/fsp_broadwell_de/include/soc/msr.h
+++ b/src/soc/intel/fsp_broadwell_de/include/soc/msr.h
@@ -39,4 +39,9 @@
 #define MSR_PRMRR_PHYS_BASE	0x1f4
 #define MSR_PRMRR_PHYS_MASK	0x1f5
 
+/* EDS vol 2 */
+#define MSR_LT_MEMORY_LOCKED	0x2e7
+#define   MSR_MEM_LOCK_BIT1	(1 << 1)
+#define   MSR_MEM_LOCK_BIT2	(1 << 2)
+
 #endif /* _SOC_MSR_H_ */
diff --git a/src/soc/intel/fsp_broadwell_de/romstage/memory.c b/src/soc/intel/fsp_broadwell_de/romstage/memory.c
index b4bc097e84..571ab091ab 100644
--- a/src/soc/intel/fsp_broadwell_de/romstage/memory.c
+++ b/src/soc/intel/fsp_broadwell_de/romstage/memory.c
@@ -13,6 +13,8 @@
  * GNU General Public License for more details.
  */
 
+#include <cpu/x86/msr.h>
+#include <soc/msr.h>
 #include <stddef.h>
 #include <device/pci_ops.h>
 #include <device/dram/ddr4.h>
@@ -85,3 +87,9 @@ void save_dimm_info(void)
 		}
 	}
 }
+
+bool memory_config_is_locked(void)
+{
+	msr_t msr = rdmsr(MSR_LT_MEMORY_LOCKED);
+	return (msr.lo & (MSR_MEM_LOCK_BIT1 | MSR_MEM_LOCK_BIT2));
+}