diff --git a/drivers/arm/css/scp/css_sds.c b/drivers/arm/css/scp/css_sds.c
index e42ee10d7..d9965c671 100644
--- a/drivers/arm/css/scp/css_sds.c
+++ b/drivers/arm/css/scp/css_sds.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -20,7 +20,7 @@ int css_scp_boot_image_xfer(void *image, unsigned int image_size)
 	int ret;
 	unsigned int image_offset, image_flags;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SCP SDS initialization failed\n");
 		panic();
@@ -28,13 +28,15 @@ int css_scp_boot_image_xfer(void *image, unsigned int image_size)
 
 	VERBOSE("Writing SCP image metadata\n");
 	image_offset = (uintptr_t) image - ARM_TRUSTED_SRAM_BASE;
-	ret = sds_struct_write(SDS_SCP_IMG_STRUCT_ID, SDS_SCP_IMG_ADDR_OFFSET,
+	ret = sds_struct_write(SDS_SCP_AP_REGION_ID,
+			SDS_SCP_IMG_STRUCT_ID, SDS_SCP_IMG_ADDR_OFFSET,
 			&image_offset, SDS_SCP_IMG_ADDR_SIZE,
 			SDS_ACCESS_MODE_NON_CACHED);
 	if (ret != SDS_OK)
 		goto sds_fail;
 
-	ret = sds_struct_write(SDS_SCP_IMG_STRUCT_ID, SDS_SCP_IMG_SIZE_OFFSET,
+	ret = sds_struct_write(SDS_SCP_AP_REGION_ID,
+			SDS_SCP_IMG_STRUCT_ID, SDS_SCP_IMG_SIZE_OFFSET,
 			&image_size, SDS_SCP_IMG_SIZE_SIZE,
 			SDS_ACCESS_MODE_NON_CACHED);
 	if (ret != SDS_OK)
@@ -42,7 +44,8 @@ int css_scp_boot_image_xfer(void *image, unsigned int image_size)
 
 	VERBOSE("Marking SCP image metadata as valid\n");
 	image_flags = SDS_SCP_IMG_VALID_FLAG_BIT;
-	ret = sds_struct_write(SDS_SCP_IMG_STRUCT_ID, SDS_SCP_IMG_FLAG_OFFSET,
+	ret = sds_struct_write(SDS_SCP_AP_REGION_ID,
+			SDS_SCP_IMG_STRUCT_ID, SDS_SCP_IMG_FLAG_OFFSET,
 			&image_flags, SDS_SCP_IMG_FLAG_SIZE,
 			SDS_ACCESS_MODE_NON_CACHED);
 	if (ret != SDS_OK)
@@ -68,7 +71,8 @@ int css_scp_boot_ready(void)
 
 	/* Wait for the SCP RAM Firmware to complete its initialization process */
 	while (retry > 0) {
-		ret = sds_struct_read(SDS_FEATURE_AVAIL_STRUCT_ID, 0,
+		ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				SDS_FEATURE_AVAIL_STRUCT_ID, 0,
 				&scp_feature_availability_flags,
 				SDS_FEATURE_AVAIL_SIZE,
 				SDS_ACCESS_MODE_NON_CACHED);
diff --git a/drivers/arm/css/sds/sds.c b/drivers/arm/css/sds/sds.c
index 1fb196c70..a5e638939 100644
--- a/drivers/arm/css/sds/sds.c
+++ b/drivers/arm/css/sds/sds.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -15,40 +15,39 @@
 
 #include "sds_private.h"
 
-/*
- * Variables used to track and maintain the state of the memory region reserved
- * for usage by the SDS framework.
- */
+/* Array of SDS memory region descriptions */
+static sds_region_desc_t *sds_regions;
 
-/* Pointer to the base of the SDS memory region */
-static uintptr_t sds_mem_base;
-
-/* Size of the SDS memory region in bytes */
-static size_t sds_mem_size;
+/* Total count of SDS memory regions */
+static unsigned int sds_region_cnt;
 
 /*
  * Perform some non-exhaustive tests to determine whether any of the fields
  * within a Structure Header contain obviously invalid data.
  * Returns SDS_OK on success, SDS_ERR_FAIL on error.
  */
-static int sds_struct_is_valid(uintptr_t header)
+static int sds_struct_is_valid(unsigned int region_id, uintptr_t header)
 {
 	size_t struct_size = GET_SDS_HEADER_STRUCT_SIZE(header);
 
 	/* Zero is not a valid identifier */
-	if (GET_SDS_HEADER_ID(header) == 0)
+	if (GET_SDS_HEADER_ID(header) == 0) {
 		return SDS_ERR_FAIL;
+	}
 
 	/* Check SDS Schema version */
-	if (GET_SDS_HEADER_VERSION(header) == SDS_REGION_SCH_VERSION)
+	if (GET_SDS_HEADER_VERSION(header) == SDS_REGION_SCH_VERSION) {
 		return SDS_ERR_FAIL;
+	}
 
 	/* The SDS Structure sizes have to be multiple of 8 */
-	if ((struct_size == 0) || ((struct_size % 8) != 0))
+	if ((struct_size == 0) || ((struct_size % 8) != 0)) {
 		return SDS_ERR_FAIL;
+	}
 
-	if (struct_size > sds_mem_size)
+	if (struct_size > sds_regions[region_id].size) {
 		return SDS_ERR_FAIL;
+	}
 
 	return SDS_OK;
 }
@@ -57,10 +56,11 @@ static int sds_struct_is_valid(uintptr_t header)
  * Validate the SDS structure headers.
  * Returns SDS_OK on success, SDS_ERR_FAIL on error.
  */
-static int validate_sds_struct_headers(void)
+static int validate_sds_struct_headers(unsigned int region_id)
 {
 	unsigned int i, structure_count;
 	uintptr_t header;
+	uintptr_t sds_mem_base = sds_regions[region_id].base;
 
 	structure_count = GET_SDS_REGION_STRUCTURE_COUNT(sds_mem_base);
 
@@ -71,7 +71,7 @@ static int validate_sds_struct_headers(void)
 
 	/* Iterate over structure headers and validate each one */
 	for (i = 0; i < structure_count; i++) {
-		if (sds_struct_is_valid(header) != SDS_OK) {
+		if (sds_struct_is_valid(region_id, header) != SDS_OK) {
 			WARN("SDS: Invalid structure header detected\n");
 			return SDS_ERR_FAIL;
 		}
@@ -84,10 +84,12 @@ static int validate_sds_struct_headers(void)
  * Get the structure header pointer corresponding to the structure ID.
  * Returns SDS_OK on success, SDS_ERR_STRUCT_NOT_FOUND on error.
  */
-static int get_struct_header(uint32_t structure_id, struct_header_t **header)
+static int get_struct_header(unsigned int region_id, uint32_t structure_id,
+			struct_header_t **header)
 {
 	unsigned int i, structure_count;
 	uintptr_t current_header;
+	uintptr_t sds_mem_base = sds_regions[region_id].base;
 
 	assert(header);
 
@@ -116,12 +118,14 @@ static int get_struct_header(uint32_t structure_id, struct_header_t **header)
  * Returns SDS_OK if structure header exists else SDS_ERR_STRUCT_NOT_FOUND
  * if not found.
  */
-int sds_struct_exists(unsigned int structure_id)
+int sds_struct_exists(unsigned int region_id, unsigned int structure_id)
 {
 	struct_header_t *header = NULL;
 	int ret;
 
-	ret = get_struct_header(structure_id, &header);
+	assert(region_id < sds_region_cnt);
+
+	ret = get_struct_header(region_id, structure_id, &header);
 	if (ret == SDS_OK) {
 		assert(header);
 	}
@@ -136,18 +140,21 @@ int sds_struct_exists(unsigned int structure_id)
  * The `data` is the pointer to store the read data of size specified by `size`.
  * Returns SDS_OK on success or corresponding error codes on failure.
  */
-int sds_struct_read(uint32_t structure_id, unsigned int fld_off,
-		void *data, size_t size, sds_access_mode_t mode)
+int sds_struct_read(unsigned int region_id, uint32_t structure_id,
+		unsigned int fld_off, void *data, size_t size,
+		sds_access_mode_t mode)
 {
 	int status;
 	uintptr_t field_base;
 	struct_header_t *header = NULL;
 
+	assert(region_id < sds_region_cnt);
+
 	if (!data)
 		return SDS_ERR_INVALID_PARAMS;
 
 	/* Check if a structure with this ID exists */
-	status = get_struct_header(structure_id, &header);
+	status = get_struct_header(region_id, structure_id, &header);
 	if (status != SDS_OK)
 		return status;
 
@@ -182,18 +189,21 @@ int sds_struct_read(uint32_t structure_id, unsigned int fld_off,
  * The `data` is the pointer to data of size specified by `size`.
  * Returns SDS_OK on success or corresponding error codes on failure.
  */
-int sds_struct_write(uint32_t structure_id, unsigned int fld_off,
-		void *data, size_t size, sds_access_mode_t mode)
+int sds_struct_write(unsigned int region_id, uint32_t structure_id,
+		unsigned int fld_off, void *data, size_t size,
+		sds_access_mode_t mode)
 {
 	int status;
 	uintptr_t field_base;
 	struct_header_t *header = NULL;
 
+	assert(region_id < sds_region_cnt);
+
 	if (!data)
 		return SDS_ERR_INVALID_PARAMS;
 
 	/* Check if a structure with this ID exists */
-	status = get_struct_header(structure_id, &header);
+	status = get_struct_header(region_id, structure_id, &header);
 	if (status != SDS_OK)
 		return status;
 
@@ -226,12 +236,18 @@ int sds_struct_write(uint32_t structure_id, unsigned int fld_off,
 
 /*
  * Initialize the SDS driver. Also verifies the SDS version and sanity of
- * the SDS structure headers.
+ * the SDS structure headers in the given SDS region.
  * Returns SDS_OK on success, SDS_ERR_FAIL on error.
  */
-int sds_init(void)
+int sds_init(unsigned int region_id)
 {
-	sds_mem_base = (uintptr_t)PLAT_ARM_SDS_MEM_BASE;
+	if (sds_regions == NULL) {
+		sds_regions = plat_sds_get_regions(&sds_region_cnt);
+	}
+
+	assert(region_id < sds_region_cnt);
+
+	uintptr_t sds_mem_base = sds_regions[region_id].base;
 
 	if (!IS_SDS_REGION_VALID(sds_mem_base)) {
 		WARN("SDS: No valid SDS Memory Region found\n");
@@ -244,15 +260,16 @@ int sds_init(void)
 		return SDS_ERR_FAIL;
 	}
 
-	sds_mem_size = GET_SDS_REGION_SIZE(sds_mem_base);
-	if (sds_mem_size > PLAT_ARM_SDS_MEM_SIZE_MAX) {
+	sds_regions[region_id].size = GET_SDS_REGION_SIZE(sds_mem_base);
+	if (sds_regions[region_id].size > PLAT_ARM_SDS_MEM_SIZE_MAX) {
 		WARN("SDS: SDS Memory Region exceeds size limit\n");
 		return SDS_ERR_FAIL;
 	}
 
-	INFO("SDS: Detected SDS Memory Region (%zu bytes)\n", sds_mem_size);
+	INFO("SDS: Detected SDS Memory Region (%zu bytes)\n",
+		sds_regions[region_id].size);
 
-	if (validate_sds_struct_headers() != SDS_OK)
+	if (validate_sds_struct_headers(region_id) != SDS_OK)
 		return SDS_ERR_FAIL;
 
 	return SDS_OK;
diff --git a/include/drivers/arm/css/sds.h b/include/drivers/arm/css/sds.h
index db4cbaaf5..ab9577512 100644
--- a/include/drivers/arm/css/sds.h
+++ b/include/drivers/arm/css/sds.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -79,12 +79,33 @@ typedef enum {
 	SDS_ACCESS_MODE_CACHED,
 } sds_access_mode_t;
 
-int sds_init(void);
-int sds_struct_exists(unsigned int structure_id);
-int sds_struct_read(uint32_t structure_id, unsigned int fld_off, void *data,
-		size_t size, sds_access_mode_t mode);
-int sds_struct_write(uint32_t structure_id, unsigned int fld_off, void *data,
-		size_t size, sds_access_mode_t mode);
+/*
+ * The following structure describes a SDS memory region. Its items are used
+ * to track and maintain the state of the memory region reserved for usage
+ * by the SDS framework.
+ *
+ * The base address of the SDS memory region is platform specific. The
+ * SDS description structure must already contain the address when it is
+ * returned by the plat_sds_get_regions() platform API during SDS region
+ * initialization.
+ * The size of the SDS memory region is dynamically discovered during the
+ * initialization of the region and written into the 'size' item of the
+ * SDS description structure.
+ */
+typedef struct {
+	uintptr_t base;	/* Pointer to the base of the SDS memory region */
+	size_t size;	/* Size of the SDS memory region in bytes */
+} sds_region_desc_t;
+
+/* API to get the platform specific SDS region description(s) */
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count);
+
+int sds_init(unsigned int region_id);
+int sds_struct_exists(unsigned int region_id, unsigned int structure_id);
+int sds_struct_read(unsigned int region_id, uint32_t structure_id,
+	unsigned int fld_off, void *data, size_t size, sds_access_mode_t mode);
+int sds_struct_write(unsigned int region_id, uint32_t structure_id,
+	unsigned int fld_off, void *data, size_t size, sds_access_mode_t mode);
 #endif /*__ASSEMBLER__ */
 
 #endif /* SDS_H */
diff --git a/include/plat/arm/css/common/css_def.h b/include/plat/arm/css/common/css_def.h
index f87f857c5..0aea54803 100644
--- a/include/plat/arm/css/common/css_def.h
+++ b/include/plat/arm/css/common/css_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -75,6 +75,7 @@
  * The SCMI Channel is placed right after the SDS region
  */
 #define CSS_SCMI_PAYLOAD_BASE		(PLAT_ARM_SDS_MEM_BASE + PLAT_ARM_SDS_MEM_SIZE_MAX)
+#define CSS_SCMI_PAYLOAD_SIZE_MAX	0x100 /* 2x128 bytes for bidirectional communication */
 #define CSS_SCMI_MHU_DB_REG_OFF		MHU_CPU_INTR_S_SET_OFFSET
 
 /* Trusted mailbox base address common to all CSS */
diff --git a/plat/arm/board/juno/include/platform_def.h b/plat/arm/board/juno/include/platform_def.h
index 5c9a7a3af..b276f7b10 100644
--- a/plat/arm/board/juno/include/platform_def.h
+++ b/plat/arm/board/juno/include/platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2023, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -246,12 +246,14 @@
 /* MHU related constants */
 #define PLAT_CSS_MHU_BASE		UL(0x2b1f0000)
 
+#if CSS_USE_SCMI_SDS_DRIVER
+/* Index of SDS region used in the communication between AP and SCP */
+#define SDS_SCP_AP_REGION_ID			U(0)
+#else
 /*
  * Base address of the first memory region used for communication between AP
  * and SCP. Used by the BOM and SCPI protocols.
- */
-#if !CSS_USE_SCMI_SDS_DRIVER
-/*
+ *
  * Note that this is located at the same address as SCP_BOOT_CFG_ADDR, which
  * means the SCP/AP configuration data gets overwritten when the AP initiates
  * communication with the SCP. The configuration data is expected to be a
@@ -261,7 +263,7 @@
 #define PLAT_CSS_SCP_COM_SHARED_MEM_BASE	(ARM_TRUSTED_SRAM_BASE + UL(0x80))
 #define PLAT_CSS_PRIMARY_CPU_SHIFT		8
 #define PLAT_CSS_PRIMARY_CPU_BIT_WIDTH		4
-#endif
+#endif /* CSS_USE_SCMI_SDS_DRIVER */
 
 /*
  * SCP_BL2 uses up whatever remaining space is available as it is loaded before
diff --git a/plat/arm/board/juno/juno_bl1_setup.c b/plat/arm/board/juno/juno_bl1_setup.c
index a9d5cc37f..2bc948d68 100644
--- a/plat/arm/board/juno/juno_bl1_setup.c
+++ b/plat/arm/board/juno/juno_bl1_setup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -32,13 +32,14 @@ static int is_watchdog_reset(void)
 	int ret;
 	uint32_t scp_reset_synd_flags;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SCP SDS initialization failed\n");
 		panic();
 	}
 
-	ret = sds_struct_read(SDS_RESET_SYNDROME_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+					SDS_RESET_SYNDROME_STRUCT_ID,
 					SDS_RESET_SYNDROME_OFFSET,
 					&scp_reset_synd_flags,
 					SDS_RESET_SYNDROME_SIZE,
diff --git a/plat/arm/board/juno/juno_common.c b/plat/arm/board/juno/juno_common.c
index 02614da4a..2cd01e417 100644
--- a/plat/arm/board/juno/juno_common.c
+++ b/plat/arm/board/juno/juno_common.c
@@ -1,14 +1,16 @@
 /*
- * Copyright (c) 2015-2023, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <drivers/arm/css/sds.h>
 #include <lib/smccc.h>
-#include <platform_def.h>
+#include <lib/utils_def.h>
 #include <services/arm_arch_svc.h>
 
 #include <plat/arm/common/plat_arm.h>
+#include <platform_def.h>
 
 /*
  * Table of memory regions for different BL stages to map using the MMU.
@@ -138,3 +140,16 @@ int32_t plat_get_soc_revision(void)
 	return (int32_t)(((sys_id >> V2M_SYS_ID_REV_SHIFT) &
 			  V2M_SYS_ID_REV_MASK) & SOC_ID_REV_MASK);
 }
+
+#if CSS_USE_SCMI_SDS_DRIVER
+static sds_region_desc_t juno_sds_regions[] = {
+	{ .base = PLAT_ARM_SDS_MEM_BASE },
+};
+
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count)
+{
+	*region_count = ARRAY_SIZE(juno_sds_regions);
+
+	return juno_sds_regions;
+}
+#endif /* CSS_USE_SCMI_SDS_DRIVER */
diff --git a/plat/arm/board/morello/include/platform_def.h b/plat/arm/board/morello/include/platform_def.h
index 993aa4687..3cf723e13 100644
--- a/plat/arm/board/morello/include/platform_def.h
+++ b/plat/arm/board/morello/include/platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2020-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -59,6 +59,10 @@
 
 #if CSS_USE_SCMI_SDS_DRIVER
 #define MORELLO_SCMI_PAYLOAD_BASE		ULL(0x45400000)
+/*
+ * Index of SDS region used in the communication with SCP
+ */
+#define SDS_SCP_AP_REGION_ID			U(0)
 #else
 #define PLAT_CSS_SCP_COM_SHARED_MEM_BASE	ULL(0x45400000)
 #endif
diff --git a/plat/arm/board/morello/morello_bl2_setup.c b/plat/arm/board/morello/morello_bl2_setup.c
index 39020e236..38e2e6a22 100644
--- a/plat/arm/board/morello/morello_bl2_setup.c
+++ b/plat/arm/board/morello/morello_bl2_setup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -155,13 +155,14 @@ void bl2_platform_setup(void)
 	int ret;
 	struct morello_plat_info plat_info;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed. ret:%d\n", ret);
 		panic();
 	}
 
-	ret = sds_struct_read(MORELLO_SDS_PLATFORM_INFO_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				MORELLO_SDS_PLATFORM_INFO_STRUCT_ID,
 				MORELLO_SDS_PLATFORM_INFO_OFFSET,
 				&plat_info,
 				MORELLO_SDS_PLATFORM_INFO_SIZE,
diff --git a/plat/arm/board/morello/morello_bl31_setup.c b/plat/arm/board/morello/morello_bl31_setup.c
index 8469cd134..637382559 100644
--- a/plat/arm/board/morello/morello_bl31_setup.c
+++ b/plat/arm/board/morello/morello_bl31_setup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2020-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -43,13 +43,14 @@ void bl31_platform_setup(void)
 #ifdef TARGET_PLATFORM_SOC
 	int ret;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed. ret:%d\n", ret);
 		panic();
 	}
 
-	ret = sds_struct_read(MORELLO_SDS_PLATFORM_INFO_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				MORELLO_SDS_PLATFORM_INFO_STRUCT_ID,
 				MORELLO_SDS_PLATFORM_INFO_OFFSET,
 				&plat_info,
 				MORELLO_SDS_PLATFORM_INFO_SIZE,
diff --git a/plat/arm/board/morello/morello_image_load.c b/plat/arm/board/morello/morello_image_load.c
index 4ea2bb301..cfe8bee58 100644
--- a/plat/arm/board/morello/morello_image_load.c
+++ b/plat/arm/board/morello/morello_image_load.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -13,6 +13,7 @@
 #include "morello_def.h"
 #include <plat/arm/common/plat_arm.h>
 #include <plat/common/platform.h>
+#include <platform_def.h>
 
 /* In client mode, a part of the DDR memory is reserved for Tag bits.
  * Calculate the usable memory size after subtracting the Tag memory.
@@ -167,13 +168,14 @@ bl_params_t *plat_get_next_bl_params(void)
 	struct morello_plat_info plat_info;
 	struct morello_firmware_version fw_version;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed. ret:%d\n", ret);
 		panic();
 	}
 
-	ret = sds_struct_read(MORELLO_SDS_PLATFORM_INFO_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				MORELLO_SDS_PLATFORM_INFO_STRUCT_ID,
 				MORELLO_SDS_PLATFORM_INFO_OFFSET,
 				&plat_info,
 				MORELLO_SDS_PLATFORM_INFO_SIZE,
@@ -183,7 +185,8 @@ bl_params_t *plat_get_next_bl_params(void)
 		panic();
 	}
 
-	ret = sds_struct_read(MORELLO_SDS_FIRMWARE_VERSION_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				MORELLO_SDS_FIRMWARE_VERSION_STRUCT_ID,
 				MORELLO_SDS_FIRMWARE_VERSION_OFFSET,
 				&fw_version,
 				MORELLO_SDS_FIRMWARE_VERSION_SIZE,
diff --git a/plat/arm/board/morello/morello_plat.c b/plat/arm/board/morello/morello_plat.c
index 2ca3d08c9..61fed642b 100644
--- a/plat/arm/board/morello/morello_plat.c
+++ b/plat/arm/board/morello/morello_plat.c
@@ -1,12 +1,14 @@
 /*
- * Copyright (c) 2020-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2020-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <assert.h>
 
+#include <drivers/arm/css/sds.h>
 #include <drivers/arm/sbsa.h>
+#include <lib/utils_def.h>
 #include <plat/arm/common/plat_arm.h>
 
 #include "morello_def.h"
@@ -68,3 +70,16 @@ void plat_arm_secure_wdt_stop(void)
 {
 	sbsa_wdog_stop(SBSA_SECURE_WDOG_BASE);
 }
+
+#if CSS_USE_SCMI_SDS_DRIVER
+static sds_region_desc_t morello_sds_regions[] = {
+	{ .base = PLAT_ARM_SDS_MEM_BASE },
+};
+
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count)
+{
+	*region_count = ARRAY_SIZE(morello_sds_regions);
+
+	return morello_sds_regions;
+}
+#endif /* CSS_USE_SCMI_SDS_DRIVER */
diff --git a/plat/arm/board/n1sdp/include/platform_def.h b/plat/arm/board/n1sdp/include/platform_def.h
index 74d0c9116..82f1e7f62 100644
--- a/plat/arm/board/n1sdp/include/platform_def.h
+++ b/plat/arm/board/n1sdp/include/platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -77,6 +77,10 @@
 
 #if CSS_USE_SCMI_SDS_DRIVER
 #define N1SDP_SCMI_PAYLOAD_BASE			0x45400000
+/*
+ * Index of SDS region used in the communication with SCP
+ */
+#define SDS_SCP_AP_REGION_ID			U(0)
 #else
 #define PLAT_CSS_SCP_COM_SHARED_MEM_BASE	0x45400000
 #endif
diff --git a/plat/arm/board/n1sdp/n1sdp_bl2_setup.c b/plat/arm/board/n1sdp/n1sdp_bl2_setup.c
index 5f8af9f34..5a5b9a5f0 100644
--- a/plat/arm/board/n1sdp/n1sdp_bl2_setup.c
+++ b/plat/arm/board/n1sdp/n1sdp_bl2_setup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Arm Limited. All rights reserved.
+ * Copyright (c) 2022-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -11,6 +11,7 @@
 
 #include "n1sdp_def.h"
 #include <plat/arm/common/plat_arm.h>
+#include <platform_def.h>
 
 struct n1sdp_plat_info {
 	bool multichip_mode;
@@ -60,13 +61,14 @@ void bl2_platform_setup(void)
 	int ret;
 	struct n1sdp_plat_info plat_info;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed\n");
 		panic();
 	}
 
-	ret = sds_struct_read(N1SDP_SDS_PLATFORM_INFO_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				N1SDP_SDS_PLATFORM_INFO_STRUCT_ID,
 				N1SDP_SDS_PLATFORM_INFO_OFFSET,
 				&plat_info,
 				N1SDP_SDS_PLATFORM_INFO_SIZE,
diff --git a/plat/arm/board/n1sdp/n1sdp_bl31_setup.c b/plat/arm/board/n1sdp/n1sdp_bl31_setup.c
index 430aab688..27ea7f7dc 100644
--- a/plat/arm/board/n1sdp/n1sdp_bl31_setup.c
+++ b/plat/arm/board/n1sdp/n1sdp_bl31_setup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -127,13 +127,14 @@ void bl31_platform_setup(void)
 	int ret;
 	struct n1sdp_plat_info plat_info;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed\n");
 		panic();
 	}
 
-	ret = sds_struct_read(N1SDP_SDS_PLATFORM_INFO_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				N1SDP_SDS_PLATFORM_INFO_STRUCT_ID,
 				N1SDP_SDS_PLATFORM_INFO_OFFSET,
 				&plat_info,
 				N1SDP_SDS_PLATFORM_INFO_SIZE,
diff --git a/plat/arm/board/n1sdp/n1sdp_image_load.c b/plat/arm/board/n1sdp/n1sdp_image_load.c
index 6c3528ce8..6ae2b2623 100644
--- a/plat/arm/board/n1sdp/n1sdp_image_load.c
+++ b/plat/arm/board/n1sdp/n1sdp_image_load.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Arm Limited. All rights reserved.
+ * Copyright (c) 2022-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -13,6 +13,7 @@
 
 #include "n1sdp_def.h"
 #include <plat/arm/common/plat_arm.h>
+#include <platform_def.h>
 
 /*
  * Platform information structure stored in SDS.
@@ -108,13 +109,14 @@ bl_params_t *plat_get_next_bl_params(void)
 	int ret;
 	struct n1sdp_plat_info plat_info;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed. ret:%d\n", ret);
 		panic();
 	}
 
-	ret = sds_struct_read(N1SDP_SDS_PLATFORM_INFO_STRUCT_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+				N1SDP_SDS_PLATFORM_INFO_STRUCT_ID,
 				N1SDP_SDS_PLATFORM_INFO_OFFSET,
 				&plat_info,
 				N1SDP_SDS_PLATFORM_INFO_SIZE,
diff --git a/plat/arm/board/n1sdp/n1sdp_plat.c b/plat/arm/board/n1sdp/n1sdp_plat.c
index 747ff068c..42efdeef7 100644
--- a/plat/arm/board/n1sdp/n1sdp_plat.c
+++ b/plat/arm/board/n1sdp/n1sdp_plat.c
@@ -1,12 +1,14 @@
 /*
- * Copyright (c) 2018-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <assert.h>
 
+#include <drivers/arm/css/sds.h>
 #include <drivers/arm/sbsa.h>
+#include <lib/utils_def.h>
 #include <plat/arm/common/plat_arm.h>
 
 #include "n1sdp_def.h"
@@ -71,3 +73,16 @@ void plat_arm_secure_wdt_stop(void)
 {
 	sbsa_wdog_stop(SBSA_SECURE_WDOG_BASE);
 }
+
+#if CSS_USE_SCMI_SDS_DRIVER
+static sds_region_desc_t n1sdp_sds_regions[] = {
+	{ .base = PLAT_ARM_SDS_MEM_BASE },
+};
+
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count)
+{
+	*region_count = ARRAY_SIZE(n1sdp_sds_regions);
+
+	return n1sdp_sds_regions;
+}
+#endif /* CSS_USE_SCMI_SDS_DRIVER */
diff --git a/plat/arm/board/tc/include/platform_def.h b/plat/arm/board/tc/include/platform_def.h
index 59fff6e2a..867750eda 100644
--- a/plat/arm/board/tc/include/platform_def.h
+++ b/plat/arm/board/tc/include/platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2023, Arm Limited. All rights reserved.
+ * Copyright (c) 2020-2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -240,6 +240,17 @@
 
 #define PLAT_ARM_SCMI_CHANNEL_COUNT	1
 
+/* Index of SDS region used in the communication with SCP */
+#define SDS_SCP_AP_REGION_ID		U(0)
+/* Index of SDS region used in the communication with RSS */
+#define SDS_RSS_AP_REGION_ID		U(1)
+/*
+ * Memory region for RSS's shared data storage (SDS)
+ * It is placed right after the SCMI payload area.
+ */
+#define PLAT_ARM_RSS_AP_SDS_MEM_BASE	(CSS_SCMI_PAYLOAD_BASE + \
+					 CSS_SCMI_PAYLOAD_SIZE_MAX)
+
 #define PLAT_ARM_CLUSTER_COUNT		U(1)
 #define PLAT_MAX_CPUS_PER_CLUSTER	U(8)
 #define PLAT_MAX_PE_PER_CPU		U(1)
diff --git a/plat/arm/board/tc/tc_plat.c b/plat/arm/board/tc/tc_plat.c
index 766bfb570..27d4b117f 100644
--- a/plat/arm/board/tc/tc_plat.c
+++ b/plat/arm/board/tc/tc_plat.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2020-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -12,6 +12,8 @@
 #include <common/bl_common.h>
 #include <common/debug.h>
 #include <drivers/arm/ccn.h>
+#include <drivers/arm/css/sds.h>
+#include <lib/utils_def.h>
 #include <plat/arm/common/plat_arm.h>
 #include <plat/common/platform.h>
 #include <drivers/arm/sbsa.h>
@@ -159,3 +161,15 @@ void plat_arm_secure_wdt_refresh(void)
 {
 	sbsa_wdog_refresh(SBSA_SECURE_WDOG_REFRESH_BASE);
 }
+
+static sds_region_desc_t tc_sds_regions[] = {
+	{ .base = PLAT_ARM_SDS_MEM_BASE },
+	{ .base = PLAT_ARM_RSS_AP_SDS_MEM_BASE },
+};
+
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count)
+{
+	*region_count = ARRAY_SIZE(tc_sds_regions);
+
+	return tc_sds_regions;
+}
diff --git a/plat/arm/css/sgi/include/sgi_base_platform_def.h b/plat/arm/css/sgi/include/sgi_base_platform_def.h
index dab5f8b21..2126a8663 100644
--- a/plat/arm/css/sgi/include/sgi_base_platform_def.h
+++ b/plat/arm/css/sgi/include/sgi_base_platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -298,6 +298,8 @@
 
 #endif
 
+/* Index of SDS region used in the communication with SCP */
+#define SDS_SCP_AP_REGION_ID			U(0)
 /* SDS ID for unusable CPU MPID list structure */
 #define SDS_ISOLATED_CPU_LIST_ID		U(128)
 
diff --git a/plat/arm/css/sgi/sgi_image_load.c b/plat/arm/css/sgi/sgi_image_load.c
index ac4bfd292..0a9bba9df 100644
--- a/plat/arm/css/sgi/sgi_image_load.c
+++ b/plat/arm/css/sgi/sgi_image_load.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2022, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -30,13 +30,14 @@ void plat_arm_sgi_get_isolated_cpu_list(struct isolated_cpu_mpid_list *list)
 {
 	int ret;
 
-	ret = sds_init();
+	ret = sds_init(SDS_SCP_AP_REGION_ID);
 	if (ret != SDS_OK) {
 		ERROR("SDS initialization failed, error: %d\n", ret);
 		panic();
 	}
 
-	ret = sds_struct_read(SDS_ISOLATED_CPU_LIST_ID, 0, &list->num_entries,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+			SDS_ISOLATED_CPU_LIST_ID, 0, &list->num_entries,
 			sizeof(list->num_entries), SDS_ACCESS_MODE_CACHED);
 	if (ret != SDS_OK) {
 		INFO("SDS CPU num elements read failed, error: %d\n", ret);
@@ -54,7 +55,8 @@ void plat_arm_sgi_get_isolated_cpu_list(struct isolated_cpu_mpid_list *list)
 		return;
 	}
 
-	ret = sds_struct_read(SDS_ISOLATED_CPU_LIST_ID,
+	ret = sds_struct_read(SDS_SCP_AP_REGION_ID,
+			SDS_ISOLATED_CPU_LIST_ID,
 			sizeof(list->num_entries),
 			&list->mpid_list,
 			sizeof(list->mpid_list[0]) * list->num_entries,
@@ -152,4 +154,3 @@ bl_params_t *plat_get_next_bl_params(void)
 
 	return arm_get_next_bl_params();
 }
-
diff --git a/plat/arm/css/sgi/sgi_plat.c b/plat/arm/css/sgi/sgi_plat.c
index 01b426e88..fe64d3431 100644
--- a/plat/arm/css/sgi/sgi_plat.c
+++ b/plat/arm/css/sgi/sgi_plat.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -11,6 +11,8 @@
 #include <common/bl_common.h>
 #include <common/debug.h>
 #include <drivers/arm/ccn.h>
+#include <drivers/arm/css/sds.h>
+#include <lib/utils_def.h>
 #include <plat/arm/common/plat_arm.h>
 #include <plat/common/platform.h>
 #include <drivers/arm/sbsa.h>
@@ -174,3 +176,14 @@ void plat_arm_secure_wdt_stop(void)
 {
 	sbsa_wdog_stop(SBSA_SECURE_WDOG_BASE);
 }
+
+static sds_region_desc_t sgi_sds_regions[] = {
+	{ .base = PLAT_ARM_SDS_MEM_BASE },
+};
+
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count)
+{
+	*region_count = ARRAY_SIZE(sgi_sds_regions);
+
+	return sgi_sds_regions;
+}
diff --git a/plat/arm/css/sgi/sgi_plat_v2.c b/plat/arm/css/sgi/sgi_plat_v2.c
index 624fed34f..d241f7096 100644
--- a/plat/arm/css/sgi/sgi_plat_v2.c
+++ b/plat/arm/css/sgi/sgi_plat_v2.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -8,9 +8,11 @@
 
 #include <platform_def.h>
 
+#include <lib/utils_def.h>
+#include <drivers/arm/css/sds.h>
+#include <drivers/arm/sbsa.h>
 #include <plat/arm/common/plat_arm.h>
 #include <plat/common/platform.h>
-#include <drivers/arm/sbsa.h>
 
 #if SPM_MM
 #include <services/spm_mm_partition.h>
@@ -176,3 +178,14 @@ void plat_arm_secure_wdt_stop(void)
 {
 	sbsa_wdog_stop(SBSA_SECURE_WDOG_BASE);
 }
+
+static sds_region_desc_t sgi_sds_regions[] = {
+	{ .base = PLAT_ARM_SDS_MEM_BASE },
+};
+
+sds_region_desc_t *plat_sds_get_regions(unsigned int *region_count)
+{
+	*region_count = ARRAY_SIZE(sgi_sds_regions);
+
+	return sgi_sds_regions;
+}