feat(hikey960): add memory sharing hooks for SPMC_AT_EL3

These allows a platform to do any System-MMU/IOMMU configuration
in line with FF-A memory sharing.

Change-Id: Id517759198421a32c5d16bf5bb99590275e77736
Signed-off-by: vallau01 <valentin.laurent@trustonic.com>
Signed-off-by: Lukas Hanel <lukas.hanel@trustonic.com>
diff --git a/plat/hisilicon/hikey960/hikey960_bl31_setup.c b/plat/hisilicon/hikey960/hikey960_bl31_setup.c
index f39476e..49918ef 100644
--- a/plat/hisilicon/hikey960/hikey960_bl31_setup.c
+++ b/plat/hisilicon/hikey960/hikey960_bl31_setup.c
@@ -22,6 +22,7 @@
 #include <lib/mmio.h>
 #include <lib/xlat_tables/xlat_tables_v2.h>
 #include <plat/common/platform.h>
+#include <services/el3_spmc_ffa_memory.h>
 
 #include <hi3660.h>
 #include <hisi_ipc.h>
@@ -182,6 +183,26 @@
 	*size = SPMC_SHARED_MEMORY_OBJ_SIZE;
 	return 0;
 }
+
+/*
+ * Add dummy implementations of memory management related platform hooks.
+ * These can be used to implement platform specific functionality to support
+ * a memory sharing/lending operation.
+ *
+ * Note: The hooks must be located as part of the initial share request and
+ * final reclaim to prevent order dependencies with operations that may take
+ * place in the normal world without visibility of the SPMC.
+ */
+int plat_spmc_shmem_begin(struct ffa_mtd *desc)
+{
+	return 0;
+}
+
+int plat_spmc_shmem_reclaim(struct ffa_mtd *desc)
+{
+	return 0;
+}
+
 #endif
 
 void bl31_platform_setup(void)