From 6a0788bc0e704283e52c80990aa2bb6e047a0cc2 Mon Sep 17 00:00:00 2001
From: Marc Bonnici <marc.bonnici@arm.com>
Date: Thu, 16 Dec 2021 18:31:02 +0000
Subject: [PATCH] feat(plat/fvp): introduce accessor function to obtain
 datastore

In order to provide the EL3 SPMC a sufficient datastore to
record memory descriptors, a accessor function is used.
This allows for the backing memory to be allocated in a
platform defined manner, to accommodate memory constraints
and desired use cases.

Provide an implementation for the Arm FVP platform to
use a default value of 512KB memory allocated in the
TZC RAM section.

Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Change-Id: I92bc55ba6e04bdad429eb52f0d2960ceda682804
---
 include/plat/common/platform.h    |  4 ++++
 plat/arm/board/fvp/fvp_el3_spmc.c | 28 ++++++++++++++++++++++++++++
 plat/arm/board/fvp/platform.mk    |  4 ++++
 3 files changed, 36 insertions(+)
 create mode 100644 plat/arm/board/fvp/fvp_el3_spmc.c

diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index 766450901..b62a63158 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -347,6 +347,10 @@ int plat_spm_sp_get_next_address(void **sp_base, size_t *sp_size,
 int plat_spm_core_manifest_load(spmc_manifest_attribute_t *manifest,
 				const void *pm_addr);
 #endif
+#if defined(SPMC_AT_EL3)
+int plat_spmc_shmem_datastore_get(uint8_t **datastore, size_t *size);
+#endif
+
 /*******************************************************************************
  * Mandatory BL image load functions(may be overridden).
  ******************************************************************************/
diff --git a/plat/arm/board/fvp/fvp_el3_spmc.c b/plat/arm/board/fvp/fvp_el3_spmc.c
new file mode 100644
index 000000000..da090c0dc
--- /dev/null
+++ b/plat/arm/board/fvp/fvp_el3_spmc.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <platform_def.h>
+
+/*
+ * On the FVP platform when using the EL3 SPMC implementation allocate the
+ * datastore for tracking shared memory descriptors in the TZC DRAM section
+ * to ensure sufficient storage can be allocated.
+ * Provide an implementation of the accessor method to allow the datastore
+ * details to be retrieved by the SPMC.
+ * The SPMC will take care of initializing the memory region.
+ */
+
+#define PLAT_SPMC_SHMEM_DATASTORE_SIZE 512 * 1024
+
+__section("arm_el3_tzc_dram") static uint8_t
+plat_spmc_shmem_datastore[PLAT_SPMC_SHMEM_DATASTORE_SIZE];
+
+int plat_spmc_shmem_datastore_get(uint8_t **datastore, size_t *size)
+{
+	*datastore = plat_spmc_shmem_datastore;
+	*size = PLAT_SPMC_SHMEM_DATASTORE_SIZE;
+	return 0;
+}
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index 89ca18540..54c5e7545 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -425,3 +425,7 @@ ENABLE_SYS_REG_TRACE_FOR_NS	:= 1
 
 # enable trace filter control registers access to NS by default
 ENABLE_TRF_FOR_NS		:= 1
+
+ifeq (${SPMC_AT_EL3}, 1)
+PLAT_BL_COMMON_SOURCES	+=	plat/arm/board/fvp/fvp_el3_spmc.c
+endif