marvell/a3700: Prevent SError accessing PCIe link while it is down

When the link goes down (e.g. during a retrain), accessing the device
configuration space can trigger an ARM64 SError interrupt. Such
conditions cannot be predicted, so to avoid a crash the SError is
ignored.

Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Change-Id: I2b1fd3296cc1c88b9ca1fe21c0924cb324eed58d

plat/marvell/a3700/common/a3700_common.mk

@@ -13,6 +13,7 @@ PLAT_INCLUDE_BASE		:= $(MARVELL_PLAT_INCLUDE_BASE)/$(PLAT_FAMILY)
 PLAT_COMMON_BASE		:= $(PLAT_FAMILY_BASE)/common
 MARVELL_DRV_BASE		:= drivers/marvell
 MARVELL_COMMON_BASE		:= $(MARVELL_PLAT_BASE)/common
+HANDLE_EA_EL3_FIRST		:= 1
 
 include $(MARVELL_PLAT_BASE)/marvell.mk
 
@@ -107,6 +108,7 @@ BL31_SOURCES		+=	lib/cpus/aarch64/cortex_a53.S		\
 				$(PLAT_COMMON_BASE)/dram_win.c		\
 				$(PLAT_COMMON_BASE)/io_addr_dec.c	\
 				$(PLAT_COMMON_BASE)/marvell_plat_config.c     \
+				$(PLAT_COMMON_BASE)/a3700_ea.c		\
 				$(PLAT_FAMILY_BASE)/$(PLAT)/plat_bl31_setup.c \
 				$(MARVELL_COMMON_BASE)/marvell_ddr_info.c	\
 				$(MARVELL_COMMON_BASE)/marvell_gicv3.c	\

plat/marvell/a3700/common/a3700_ea.c

@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2019 Repk repk@triplefau.lt
+ *
+ * SPDX-License-Identifier:	BSD-3-Clause
+ * https://spdx.org/licenses
+ */
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <arch_helpers.h>
+
+#define ADVK_SERROR_SYNDROME 0xbf000002
+
+void plat_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *cookie,
+		void *handle, uint64_t flags)
+{
+	if (syndrome != ADVK_SERROR_SYNDROME) {
+		ERROR("Unhandled External Abort received on 0x%lx at EL3!\n",
+			read_mpidr_el1());
+		ERROR(" exception reason=%u syndrome=0x%llx\n", ea_reason,
+				syndrome);
+		panic();
+	}
+}