Adding upstream version 2.8.0+dfsg.upstream/2.8.0+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

29 files changed, 2845 insertions, 0 deletions

diff --git a/plat/arm/css/common/aarch32/css_helpers.S b/plat/arm/css/common/aarch32/css_helpers.S
new file mode 100644
index 0000000..d47e13d
--- /dev/null
+++ b/plat/arm/css/common/aarch32/css_helpers.S
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <cpu_macros.S>
+#include <platform_def.h>
+
+	.weak	plat_secondary_cold_boot_setup
+	.weak	plat_get_my_entrypoint
+	.globl	css_calc_core_pos_swap_cluster
+	.weak	plat_is_my_cpu_primary
+
+	/* ---------------------------------------------------------------------
+	 * void plat_secondary_cold_boot_setup(void);
+	 * In the normal boot flow, cold-booting secondary
+	 * CPUs is not yet implemented and they panic.
+	 * ---------------------------------------------------------------------
+	 */
+func plat_secondary_cold_boot_setup
+	/* TODO: Implement secondary CPU cold boot setup on CSS platforms */
+cb_panic:
+	b	cb_panic
+endfunc plat_secondary_cold_boot_setup
+
+	/* ---------------------------------------------------------------------
+	 * uintptr_t plat_get_my_entrypoint (void);
+	 *
+	 * Main job of this routine is to distinguish between a cold and a warm
+	 * boot. On CSS platforms, this distinction is based on the contents of
+	 * the Trusted Mailbox. It is initialised to zero by the SCP before the
+	 * AP cores are released from reset. Therefore, a zero mailbox means
+	 * it's a cold reset.
+	 *
+	 * This functions returns the contents of the mailbox, i.e.:
+	 *  - 0 for a cold boot;
+	 *  - the warm boot entrypoint for a warm boot.
+	 * ---------------------------------------------------------------------
+	 */
+func plat_get_my_entrypoint
+	ldr	r0, =PLAT_ARM_TRUSTED_MAILBOX_BASE
+	ldr	r0, [r0]
+	bx	lr
+endfunc plat_get_my_entrypoint
+
+	/* -----------------------------------------------------------
+	 * unsigned int css_calc_core_pos_swap_cluster(u_register_t mpidr)
+	 * Utility function to calculate the core position by
+	 * swapping the cluster order. This is necessary in order to
+	 * match the format of the boot information passed by the SCP
+	 * and read in plat_is_my_cpu_primary below.
+	 * -----------------------------------------------------------
+	 */
+func css_calc_core_pos_swap_cluster
+	and	r1, r0, #MPIDR_CPU_MASK
+	and	r0, r0, #MPIDR_CLUSTER_MASK
+	eor	r0, r0, #(1 << MPIDR_AFFINITY_BITS)  // swap cluster order
+	add	r0, r1, r0, LSR #6
+	bx	lr
+endfunc css_calc_core_pos_swap_cluster
+
+	/* -----------------------------------------------------
+	 * unsigned int plat_is_my_cpu_primary (void);
+	 *
+	 * Find out whether the current cpu is the primary
+	 * cpu (applicable ony after a cold boot)
+	 * -----------------------------------------------------
+	 */
+#if CSS_USE_SCMI_SDS_DRIVER
+func plat_is_my_cpu_primary
+	mov	r10, lr
+	bl	plat_my_core_pos
+	mov	r4, r0
+	bl	sds_get_primary_cpu_id
+	/* Check for error */
+	mov	r1, #0xffffffff
+	cmp	r0, r1
+	beq	1f
+	cmp	r0, r4
+	moveq	r0, #1
+	movne	r0, #0
+	bx	r10
+1:
+	no_ret	plat_panic_handler
+endfunc plat_is_my_cpu_primary
+#else
+func plat_is_my_cpu_primary
+	mov	r10, lr
+	bl	plat_my_core_pos
+	ldr	r1, =SCP_BOOT_CFG_ADDR
+	ldr	r1, [r1]
+	ubfx	r1, r1, #PLAT_CSS_PRIMARY_CPU_SHIFT, \
+			#PLAT_CSS_PRIMARY_CPU_BIT_WIDTH
+	cmp	r0, r1
+	moveq	r0, #1
+	movne	r0, #0
+	bx	r10
+endfunc plat_is_my_cpu_primary
+#endif
diff --git a/plat/arm/css/common/aarch64/css_helpers.S b/plat/arm/css/common/aarch64/css_helpers.S
new file mode 100644
index 0000000..01669be
--- /dev/null
+++ b/plat/arm/css/common/aarch64/css_helpers.S
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <cpu_macros.S>
+#include <platform_def.h>
+
+	.weak	plat_secondary_cold_boot_setup
+	.weak	plat_get_my_entrypoint
+	.globl	css_calc_core_pos_swap_cluster
+	.weak	plat_is_my_cpu_primary
+
+	/* ---------------------------------------------------------------------
+	 * void plat_secondary_cold_boot_setup(void);
+	 *
+	 * In the normal boot flow, cold-booting secondary CPUs is not yet
+	 * implemented and they panic.
+	 *
+	 * When booting an EL3 payload, secondary CPUs are placed in a holding
+	 * pen, waiting for their mailbox to be populated. Note that all CPUs
+	 * share the same mailbox ; therefore, populating it will release all
+	 * CPUs from their holding pen. If finer-grained control is needed then
+	 * this should be handled in the code that secondary CPUs jump to.
+	 * ---------------------------------------------------------------------
+	 */
+func plat_secondary_cold_boot_setup
+#ifndef EL3_PAYLOAD_BASE
+	/* TODO: Implement secondary CPU cold boot setup on CSS platforms */
+cb_panic:
+	b	cb_panic
+#else
+	mov_imm	x0, PLAT_ARM_TRUSTED_MAILBOX_BASE
+
+	/* Wait until the mailbox gets populated */
+poll_mailbox:
+	ldr	x1, [x0]
+	cbz	x1, 1f
+	br	x1
+1:
+	wfe
+	b	poll_mailbox
+#endif /* EL3_PAYLOAD_BASE */
+endfunc plat_secondary_cold_boot_setup
+
+	/* ---------------------------------------------------------------------
+	 * uintptr_t plat_get_my_entrypoint (void);
+	 *
+	 * Main job of this routine is to distinguish between a cold and a warm
+	 * boot. On CSS platforms, this distinction is based on the contents of
+	 * the Trusted Mailbox. It is initialised to zero by the SCP before the
+	 * AP cores are released from reset. Therefore, a zero mailbox means
+	 * it's a cold reset.
+	 *
+	 * This functions returns the contents of the mailbox, i.e.:
+	 *  - 0 for a cold boot;
+	 *  - the warm boot entrypoint for a warm boot.
+	 * ---------------------------------------------------------------------
+	 */
+func plat_get_my_entrypoint
+	mov_imm	x0, PLAT_ARM_TRUSTED_MAILBOX_BASE
+	ldr	x0, [x0]
+	ret
+endfunc plat_get_my_entrypoint
+
+	/* -----------------------------------------------------------
+	 * unsigned int css_calc_core_pos_swap_cluster(u_register_t mpidr)
+	 * Utility function to calculate the core position by
+	 * swapping the cluster order. This is necessary in order to
+	 * match the format of the boot information passed by the SCP
+	 * and read in plat_is_my_cpu_primary below.
+	 * -----------------------------------------------------------
+	 */
+func css_calc_core_pos_swap_cluster
+	and	x1, x0, #MPIDR_CPU_MASK
+	and	x0, x0, #MPIDR_CLUSTER_MASK
+	eor	x0, x0, #(1 << MPIDR_AFFINITY_BITS)  // swap cluster order
+	add	x0, x1, x0, LSR #6
+	ret
+endfunc css_calc_core_pos_swap_cluster
+
+	/* -----------------------------------------------------
+	 * unsigned int plat_is_my_cpu_primary (void);
+	 *
+	 * Find out whether the current cpu is the primary
+	 * cpu (applicable ony after a cold boot)
+	 * -----------------------------------------------------
+	 */
+#if CSS_USE_SCMI_SDS_DRIVER
+func plat_is_my_cpu_primary
+	mov	x9, x30
+	bl	plat_my_core_pos
+	mov	x4, x0
+	bl	sds_get_primary_cpu_id
+	/* Check for error */
+	mov	x1, #0xffffffff
+	cmp	x0, x1
+	b.eq	1f
+	cmp	x0, x4
+	cset	w0, eq
+	ret	x9
+1:
+	no_ret	plat_panic_handler
+endfunc plat_is_my_cpu_primary
+#else
+func plat_is_my_cpu_primary
+	mov	x9, x30
+	bl	plat_my_core_pos
+	mov_imm	x1, SCP_BOOT_CFG_ADDR
+	ldr	x1, [x1]
+	ubfx	x1, x1, #PLAT_CSS_PRIMARY_CPU_SHIFT, \
+			#PLAT_CSS_PRIMARY_CPU_BIT_WIDTH
+	cmp	x0, x1
+	cset	w0, eq
+	ret	x9
+endfunc plat_is_my_cpu_primary
+#endif
diff --git a/plat/arm/css/common/css_bl1_setup.c b/plat/arm/css/common/css_bl1_setup.c
new file mode 100644
index 0000000..596cc3d
--- /dev/null
+++ b/plat/arm/css/common/css_bl1_setup.c
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <plat/arm/common/plat_arm.h>
+#include <plat/arm/soc/common/soc_css.h>
+#include <plat/common/platform.h>
+
+void bl1_platform_setup(void)
+{
+	arm_bl1_platform_setup();
+	/*
+	 * Do ARM CSS SoC security setup.
+	 * BL1 needs to enable normal world access to memory.
+	 */
+	soc_css_security_setup();
+}
+
diff --git a/plat/arm/css/common/css_bl2_setup.c b/plat/arm/css/common/css_bl2_setup.c
new file mode 100644
index 0000000..002c6eb
--- /dev/null
+++ b/plat/arm/css/common/css_bl2_setup.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <string.h>
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <drivers/arm/css/css_scp.h>
+#include <lib/mmio.h>
+#include <lib/utils.h>
+#include <plat/arm/common/plat_arm.h>
+#include <platform_def.h>
+
+/* Weak definition may be overridden in specific CSS based platform */
+#pragma weak plat_arm_bl2_handle_scp_bl2
+
+/*******************************************************************************
+ * Transfer SCP_BL2 from Trusted RAM using the SCP Download protocol.
+ * Return 0 on success, -1 otherwise.
+ ******************************************************************************/
+int plat_arm_bl2_handle_scp_bl2(image_info_t *scp_bl2_image_info)
+{
+	int ret;
+
+	INFO("BL2: Initiating SCP_BL2 transfer to SCP\n");
+
+	ret = css_scp_boot_image_xfer((void *)scp_bl2_image_info->image_base,
+		scp_bl2_image_info->image_size);
+
+	if (ret == 0)
+		ret = css_scp_boot_ready();
+
+	if (ret == 0)
+		INFO("BL2: SCP_BL2 transferred to SCP\n");
+	else
+		ERROR("BL2: SCP_BL2 transfer failure\n");
+
+	return ret;
+}
+
+#if !CSS_USE_SCMI_SDS_DRIVER
+# if defined(EL3_PAYLOAD_BASE) || JUNO_AARCH32_EL3_RUNTIME
+
+/*
+ * We need to override some of the platform functions when booting an EL3
+ * payload or SP_MIN on Juno AArch32. This needs to be done only for
+ * SCPI/BOM SCP systems as in case of SDS, the structures remain in memory and
+ * don't need to be overwritten.
+ */
+
+static unsigned int scp_boot_config;
+
+void bl2_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+			u_register_t arg2, u_register_t arg3)
+{
+	arm_bl2_early_platform_setup((uintptr_t)arg0, (meminfo_t *)arg1);
+
+	/* Save SCP Boot config before it gets overwritten by SCP_BL2 loading */
+	scp_boot_config = mmio_read_32(SCP_BOOT_CFG_ADDR);
+	VERBOSE("BL2: Saved SCP Boot config = 0x%x\n", scp_boot_config);
+}
+
+void bl2_platform_setup(void)
+{
+	arm_bl2_platform_setup();
+
+	/*
+	 * Before releasing the AP cores out of reset, the SCP writes some data
+	 * at the beginning of the Trusted SRAM. It is is overwritten before
+	 * reaching this function. We need to restore this data, as if the
+	 * target had just come out of reset. This implies:
+	 *  - zeroing the first 128 bytes of Trusted SRAM using zeromem instead
+	 *    of zero_normalmem since this is device memory.
+	 *  - restoring the SCP boot configuration.
+	 */
+	VERBOSE("BL2: Restoring SCP reset data in Trusted SRAM\n");
+	zeromem((void *) ARM_SHARED_RAM_BASE, 128);
+	mmio_write_32(SCP_BOOT_CFG_ADDR, scp_boot_config);
+}
+
+# endif /* EL3_PAYLOAD_BASE */
+
+#endif /* CSS_USE_SCMI_SDS_DRIVER */
diff --git a/plat/arm/css/common/css_bl2u_setup.c b/plat/arm/css/common/css_bl2u_setup.c
new file mode 100644
index 0000000..15cf4f6
--- /dev/null
+++ b/plat/arm/css/common/css_bl2u_setup.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <drivers/arm/css/css_scp.h>
+#include <plat/arm/common/plat_arm.h>
+#include <plat/common/platform.h>
+
+/* Weak definition may be overridden in specific CSS based platform */
+#pragma weak bl2u_plat_handle_scp_bl2u
+
+/* Data structure which holds the SCP_BL2U image info for BL2U */
+static image_info_t scp_bl2u_image_info;
+
+/*******************************************************************************
+ * BL1 can pass platform dependent information to BL2U in x1.
+ * In case of ARM CSS platforms x1 contains SCP_BL2U image info.
+ * In case of ARM FVP platforms x1 is not used.
+ * In both cases, x0 contains the extents of the memory available to BL2U
+ ******************************************************************************/
+void bl2u_early_platform_setup(meminfo_t *mem_layout, void *plat_info)
+{
+	if (!plat_info)
+		panic();
+
+	arm_bl2u_early_platform_setup(mem_layout, plat_info);
+
+	scp_bl2u_image_info = *(image_info_t *)plat_info;
+}
+
+/*******************************************************************************
+ * Transfer SCP_BL2U from Trusted RAM using the SCP Download protocol.
+ ******************************************************************************/
+int bl2u_plat_handle_scp_bl2u(void)
+{
+	int ret;
+
+	INFO("BL2U: Initiating SCP_BL2U transfer to SCP\n");
+
+	ret = css_scp_boot_image_xfer((void *)scp_bl2u_image_info.image_base,
+		scp_bl2u_image_info.image_size);
+
+	if (ret == 0)
+		ret = css_scp_boot_ready();
+
+	if (ret == 0)
+		INFO("BL2U: SCP_BL2U transferred to SCP\n");
+	else
+		ERROR("BL2U: SCP_BL2U transfer failure\n");
+
+	return ret;
+}
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk
new file mode 100644
index 0000000..1e4851c
--- /dev/null
+++ b/plat/arm/css/common/css_common.mk
@@ -0,0 +1,97 @@
+#
+# Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+
+# By default, SCP images are needed by CSS platforms.
+CSS_LOAD_SCP_IMAGES	?=	1
+
+# By default, SCMI driver is disabled for CSS platforms
+CSS_USE_SCMI_SDS_DRIVER	?=	0
+
+PLAT_INCLUDES		+=	-Iinclude/plat/arm/css/common/aarch64
+
+
+PLAT_BL_COMMON_SOURCES	+=	plat/arm/css/common/${ARCH}/css_helpers.S
+
+BL1_SOURCES		+=	plat/arm/css/common/css_bl1_setup.c
+
+BL2_SOURCES		+=	plat/arm/css/common/css_bl2_setup.c
+
+BL2U_SOURCES		+=	plat/arm/css/common/css_bl2u_setup.c
+
+BL31_SOURCES		+=	plat/arm/css/common/css_pm.c			\
+				plat/arm/css/common/css_topology.c
+
+ifeq (${CSS_USE_SCMI_SDS_DRIVER},0)
+BL31_SOURCES		+=	drivers/arm/css/mhu/css_mhu.c			\
+				drivers/arm/css/scp/css_pm_scpi.c		\
+				drivers/arm/css/scpi/css_scpi.c
+else
+BL31_SOURCES		+=	drivers/arm/css/mhu/css_mhu_doorbell.c		\
+				drivers/arm/css/scmi/scmi_ap_core_proto.c	\
+				drivers/arm/css/scmi/scmi_common.c		\
+				drivers/arm/css/scmi/scmi_pwr_dmn_proto.c	\
+				drivers/arm/css/scmi/scmi_sys_pwr_proto.c	\
+				drivers/delay_timer/delay_timer.c		\
+				drivers/arm/css/scp/css_pm_scmi.c
+endif
+
+# Process CSS_LOAD_SCP_IMAGES flag
+$(eval $(call assert_boolean,CSS_LOAD_SCP_IMAGES))
+$(eval $(call add_define,CSS_LOAD_SCP_IMAGES))
+
+ifeq (${CSS_LOAD_SCP_IMAGES},1)
+  NEED_SCP_BL2 := yes
+  ifneq (${TRUSTED_BOARD_BOOT},0)
+    $(eval $(call TOOL_ADD_IMG,scp_bl2u,--scp-fwu-cfg,FWU_))
+  endif
+
+  ifeq (${CSS_USE_SCMI_SDS_DRIVER},1)
+    BL2U_SOURCES	+=	drivers/arm/css/scp/css_sds.c			\
+				drivers/arm/css/sds/sds.c
+
+    BL2_SOURCES		+=	drivers/arm/css/scp/css_sds.c			\
+				drivers/arm/css/sds/sds.c
+  else
+    BL2U_SOURCES	+=	drivers/arm/css/mhu/css_mhu.c			\
+				drivers/arm/css/scp/css_bom_bootloader.c	\
+				drivers/arm/css/scpi/css_scpi.c
+
+    BL2_SOURCES		+=	drivers/arm/css/mhu/css_mhu.c			\
+				drivers/arm/css/scp/css_bom_bootloader.c	\
+				drivers/arm/css/scpi/css_scpi.c
+    # Enable option to detect whether the SCP ROM firmware in use predates version
+    # 1.7.0 and therefore, is incompatible.
+    CSS_DETECT_PRE_1_7_0_SCP	:=	1
+
+    # Process CSS_DETECT_PRE_1_7_0_SCP flag
+    $(eval $(call assert_boolean,CSS_DETECT_PRE_1_7_0_SCP))
+    $(eval $(call add_define,CSS_DETECT_PRE_1_7_0_SCP))
+  endif
+endif
+
+ifeq (${CSS_USE_SCMI_SDS_DRIVER},1)
+  PLAT_BL_COMMON_SOURCES	+=	drivers/arm/css/sds/${ARCH}/sds_helpers.S
+endif
+
+# Process CSS_USE_SCMI_SDS_DRIVER flag
+$(eval $(call assert_boolean,CSS_USE_SCMI_SDS_DRIVER))
+$(eval $(call add_define,CSS_USE_SCMI_SDS_DRIVER))
+
+# Process CSS_NON_SECURE_UART flag
+# This undocumented build option is only to enable debug access to the UART
+# from non secure code, which is useful on some platforms.
+# Default (obviously) is off.
+CSS_NON_SECURE_UART		:= 0
+$(eval $(call assert_boolean,CSS_NON_SECURE_UART))
+$(eval $(call add_define,CSS_NON_SECURE_UART))
+
+# Process CSS_SYSTEM_GRACEFUL_RESET flag
+# This build option can be used on CSS platforms that require all the CPUs
+# to execute the CPU specific power down sequence to complete a warm reboot
+# sequence in which only the CPUs are power cycled.
+CSS_SYSTEM_GRACEFUL_RESET	:= 0
+$(eval $(call add_define,CSS_SYSTEM_GRACEFUL_RESET))
diff --git a/plat/arm/css/common/css_pm.c b/plat/arm/css/common/css_pm.c
new file mode 100644
index 0000000..9b2639c
--- /dev/null
+++ b/plat/arm/css/common/css_pm.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <platform_def.h>
+
+#include <arch_helpers.h>
+#include <bl31/interrupt_mgmt.h>
+#include <common/debug.h>
+#include <drivers/arm/css/css_scp.h>
+#include <lib/cassert.h>
+#include <plat/arm/common/plat_arm.h>
+
+#include <plat/common/platform.h>
+
+#include <plat/arm/css/common/css_pm.h>
+
+/* Allow CSS platforms to override `plat_arm_psci_pm_ops` */
+#pragma weak plat_arm_psci_pm_ops
+
+#if ARM_RECOM_STATE_ID_ENC
+/*
+ *  The table storing the valid idle power states. Ensure that the
+ *  array entries are populated in ascending order of state-id to
+ *  enable us to use binary search during power state validation.
+ *  The table must be terminated by a NULL entry.
+ */
+const unsigned int arm_pm_idle_states[] = {
+	/* State-id - 0x001 */
+	arm_make_pwrstate_lvl2(ARM_LOCAL_STATE_RUN, ARM_LOCAL_STATE_RUN,
+		ARM_LOCAL_STATE_RET, ARM_PWR_LVL0, PSTATE_TYPE_STANDBY),
+	/* State-id - 0x002 */
+	arm_make_pwrstate_lvl2(ARM_LOCAL_STATE_RUN, ARM_LOCAL_STATE_RUN,
+		ARM_LOCAL_STATE_OFF, ARM_PWR_LVL0, PSTATE_TYPE_POWERDOWN),
+	/* State-id - 0x022 */
+	arm_make_pwrstate_lvl2(ARM_LOCAL_STATE_RUN, ARM_LOCAL_STATE_OFF,
+		ARM_LOCAL_STATE_OFF, ARM_PWR_LVL1, PSTATE_TYPE_POWERDOWN),
+#if PLAT_MAX_PWR_LVL > ARM_PWR_LVL1
+	/* State-id - 0x222 */
+	arm_make_pwrstate_lvl2(ARM_LOCAL_STATE_OFF, ARM_LOCAL_STATE_OFF,
+		ARM_LOCAL_STATE_OFF, ARM_PWR_LVL2, PSTATE_TYPE_POWERDOWN),
+#endif
+	0,
+};
+#endif /* __ARM_RECOM_STATE_ID_ENC__ */
+
+/*
+ * All the power management helpers in this file assume at least cluster power
+ * level is supported.
+ */
+CASSERT(PLAT_MAX_PWR_LVL >= ARM_PWR_LVL1,
+		assert_max_pwr_lvl_supported_mismatch);
+
+/*
+ * Ensure that the PLAT_MAX_PWR_LVL is not greater than CSS_SYSTEM_PWR_DMN_LVL
+ * assumed by the CSS layer.
+ */
+CASSERT(PLAT_MAX_PWR_LVL <= CSS_SYSTEM_PWR_DMN_LVL,
+		assert_max_pwr_lvl_higher_than_css_sys_lvl);
+
+/*******************************************************************************
+ * Handler called when a power domain is about to be turned on. The
+ * level and mpidr determine the affinity instance.
+ ******************************************************************************/
+int css_pwr_domain_on(u_register_t mpidr)
+{
+	css_scp_on(mpidr);
+
+	return PSCI_E_SUCCESS;
+}
+
+static void css_pwr_domain_on_finisher_common(
+		const psci_power_state_t *target_state)
+{
+	assert(CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF);
+
+	/*
+	 * Perform the common cluster specific operations i.e enable coherency
+	 * if this cluster was off.
+	 */
+	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
+		plat_arm_interconnect_enter_coherency();
+}
+
+/*******************************************************************************
+ * Handler called when a power level has just been powered on after
+ * being turned off earlier. The target_state encodes the low power state that
+ * each level has woken up from. This handler would never be invoked with
+ * the system power domain uninitialized as either the primary would have taken
+ * care of it as part of cold boot or the first core awakened from system
+ * suspend would have already initialized it.
+ ******************************************************************************/
+void css_pwr_domain_on_finish(const psci_power_state_t *target_state)
+{
+	/* Assert that the system power domain need not be initialized */
+	assert(css_system_pwr_state(target_state) == ARM_LOCAL_STATE_RUN);
+
+	css_pwr_domain_on_finisher_common(target_state);
+}
+
+/*******************************************************************************
+ * Handler called when a power domain has just been powered on and the cpu
+ * and its cluster are fully participating in coherent transaction on the
+ * interconnect. Data cache must be enabled for CPU at this point.
+ ******************************************************************************/
+void css_pwr_domain_on_finish_late(const psci_power_state_t *target_state)
+{
+	/* Program the gic per-cpu distributor or re-distributor interface */
+	plat_arm_gic_pcpu_init();
+
+	/* Enable the gic cpu interface */
+	plat_arm_gic_cpuif_enable();
+
+	/* Setup the CPU power down request interrupt for secondary core(s) */
+	css_setup_cpu_pwr_down_intr();
+}
+
+/*******************************************************************************
+ * Common function called while turning a cpu off or suspending it. It is called
+ * from css_off() or css_suspend() when these functions in turn are called for
+ * power domain at the highest power level which will be powered down. It
+ * performs the actions common to the OFF and SUSPEND calls.
+ ******************************************************************************/
+static void css_power_down_common(const psci_power_state_t *target_state)
+{
+	/* Prevent interrupts from spuriously waking up this cpu */
+	plat_arm_gic_cpuif_disable();
+
+	/* Turn redistributor off */
+	plat_arm_gic_redistif_off();
+
+	/* Cluster is to be turned off, so disable coherency */
+	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF) {
+		plat_arm_interconnect_exit_coherency();
+
+#if HW_ASSISTED_COHERENCY
+		uint32_t reg;
+
+		/*
+		 * If we have determined this core to be the last man standing and we
+		 * intend to power down the cluster proactively, we provide a hint to
+		 * the power controller that cluster power is not required when all
+		 * cores are powered down.
+		 * Note that this is only an advisory to power controller and is supported
+		 * by SoCs with DynamIQ Shared Units only.
+		 */
+		reg = read_clusterpwrdn();
+
+		/* Clear and set bit 0 : Cluster power not required */
+		reg &= ~DSU_CLUSTER_PWR_MASK;
+		reg |= DSU_CLUSTER_PWR_OFF;
+		write_clusterpwrdn(reg);
+#endif
+	}
+}
+
+/*******************************************************************************
+ * Handler called when a power domain is about to be turned off. The
+ * target_state encodes the power state that each level should transition to.
+ ******************************************************************************/
+void css_pwr_domain_off(const psci_power_state_t *target_state)
+{
+	assert(CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF);
+	css_power_down_common(target_state);
+	css_scp_off(target_state);
+}
+
+/*******************************************************************************
+ * Handler called when a power domain is about to be suspended. The
+ * target_state encodes the power state that each level should transition to.
+ ******************************************************************************/
+void css_pwr_domain_suspend(const psci_power_state_t *target_state)
+{
+	/*
+	 * CSS currently supports retention only at cpu level. Just return
+	 * as nothing is to be done for retention.
+	 */
+	if (CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_RET)
+		return;
+
+
+	assert(CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF);
+	css_power_down_common(target_state);
+
+	/* Perform system domain state saving if issuing system suspend */
+	if (css_system_pwr_state(target_state) == ARM_LOCAL_STATE_OFF) {
+		arm_system_pwr_domain_save();
+
+		/* Power off the Redistributor after having saved its context */
+		plat_arm_gic_redistif_off();
+	}
+
+	css_scp_suspend(target_state);
+}
+
+/*******************************************************************************
+ * Handler called when a power domain has just been powered on after
+ * having been suspended earlier. The target_state encodes the low power state
+ * that each level has woken up from.
+ * TODO: At the moment we reuse the on finisher and reinitialize the secure
+ * context. Need to implement a separate suspend finisher.
+ ******************************************************************************/
+void css_pwr_domain_suspend_finish(
+				const psci_power_state_t *target_state)
+{
+	/* Return as nothing is to be done on waking up from retention. */
+	if (CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_RET)
+		return;
+
+	/* Perform system domain restore if woken up from system suspend */
+	if (css_system_pwr_state(target_state) == ARM_LOCAL_STATE_OFF)
+		/*
+		 * At this point, the Distributor must be powered on to be ready
+		 * to have its state restored. The Redistributor will be powered
+		 * on as part of gicv3_rdistif_init_restore.
+		 */
+		arm_system_pwr_domain_resume();
+
+	css_pwr_domain_on_finisher_common(target_state);
+
+	/* Enable the gic cpu interface */
+	plat_arm_gic_cpuif_enable();
+}
+
+/*******************************************************************************
+ * Handlers to shutdown/reboot the system
+ ******************************************************************************/
+void __dead2 css_system_off(void)
+{
+	css_scp_sys_shutdown();
+}
+
+void __dead2 css_system_reset(void)
+{
+	css_scp_sys_reboot();
+}
+
+/*******************************************************************************
+ * Handler called when the CPU power domain is about to enter standby.
+ ******************************************************************************/
+void css_cpu_standby(plat_local_state_t cpu_state)
+{
+	unsigned int scr;
+
+	assert(cpu_state == ARM_LOCAL_STATE_RET);
+
+	scr = read_scr_el3();
+	/*
+	 * Enable the Non secure interrupt to wake the CPU.
+	 * In GICv3 affinity routing mode, the non secure group1 interrupts use
+	 * the PhysicalFIQ at EL3 whereas in GICv2, it uses the PhysicalIRQ.
+	 * Enabling both the bits works for both GICv2 mode and GICv3 affinity
+	 * routing mode.
+	 */
+	write_scr_el3(scr | SCR_IRQ_BIT | SCR_FIQ_BIT);
+	isb();
+	dsb();
+	wfi();
+
+	/*
+	 * Restore SCR to the original value, synchronisation of scr_el3 is
+	 * done by eret while el3_exit to save some execution cycles.
+	 */
+	write_scr_el3(scr);
+}
+
+/*******************************************************************************
+ * Handler called to return the 'req_state' for system suspend.
+ ******************************************************************************/
+void css_get_sys_suspend_power_state(psci_power_state_t *req_state)
+{
+	unsigned int i;
+
+	/*
+	 * System Suspend is supported only if the system power domain node
+	 * is implemented.
+	 */
+	assert(PLAT_MAX_PWR_LVL == CSS_SYSTEM_PWR_DMN_LVL);
+
+	for (i = ARM_PWR_LVL0; i <= PLAT_MAX_PWR_LVL; i++)
+		req_state->pwr_domain_state[i] = ARM_LOCAL_STATE_OFF;
+}
+
+/*******************************************************************************
+ * Handler to query CPU/cluster power states from SCP
+ ******************************************************************************/
+int css_node_hw_state(u_register_t mpidr, unsigned int power_level)
+{
+	return css_scp_get_power_state(mpidr, power_level);
+}
+
+/*
+ * The system power domain suspend is only supported only via
+ * PSCI SYSTEM_SUSPEND API. PSCI CPU_SUSPEND request to system power domain
+ * will be downgraded to the lower level.
+ */
+static int css_validate_power_state(unsigned int power_state,
+			    psci_power_state_t *req_state)
+{
+	int rc;
+	rc = arm_validate_power_state(power_state, req_state);
+
+	/*
+	 * Ensure that we don't overrun the pwr_domain_state array in the case
+	 * where the platform supported max power level is less than the system
+	 * power level
+	 */
+
+#if (PLAT_MAX_PWR_LVL == CSS_SYSTEM_PWR_DMN_LVL)
+
+	/*
+	 * Ensure that the system power domain level is never suspended
+	 * via PSCI CPU SUSPEND API. Currently system suspend is only
+	 * supported via PSCI SYSTEM SUSPEND API.
+	 */
+
+	req_state->pwr_domain_state[CSS_SYSTEM_PWR_DMN_LVL] =
+							ARM_LOCAL_STATE_RUN;
+#endif
+
+	return rc;
+}
+
+/*
+ * Custom `translate_power_state_by_mpidr` handler for CSS. Unlike in the
+ * `css_validate_power_state`, we do not downgrade the system power
+ * domain level request in `power_state` as it will be used to query the
+ * PSCI_STAT_COUNT/RESIDENCY at the system power domain level.
+ */
+static int css_translate_power_state_by_mpidr(u_register_t mpidr,
+		unsigned int power_state,
+		psci_power_state_t *output_state)
+{
+	return arm_validate_power_state(power_state, output_state);
+}
+
+/*
+ * Setup the SGI interrupt that will be used trigger the execution of power
+ * down sequence for all the secondary cores. This interrupt is setup to be
+ * handled in EL3 context at a priority defined by the platform.
+ */
+void css_setup_cpu_pwr_down_intr(void)
+{
+#if CSS_SYSTEM_GRACEFUL_RESET
+	plat_ic_set_interrupt_type(CSS_CPU_PWR_DOWN_REQ_INTR, INTR_TYPE_EL3);
+	plat_ic_set_interrupt_priority(CSS_CPU_PWR_DOWN_REQ_INTR,
+			PLAT_REBOOT_PRI);
+	plat_ic_enable_interrupt(CSS_CPU_PWR_DOWN_REQ_INTR);
+#endif
+}
+
+/*
+ * For a graceful shutdown/reboot, each CPU in the system should do their power
+ * down sequence. On a PSCI shutdown/reboot request, only one CPU gets an
+ * opportunity to do the powerdown sequence. To achieve graceful reset, of all
+ * cores in the system, the CPU gets the opportunity raise warm reboot SGI to
+ * rest of the CPUs which are online. Add handler for the reboot SGI where the
+ * rest of the CPU execute the powerdown sequence.
+ */
+int css_reboot_interrupt_handler(uint32_t intr_raw, uint32_t flags,
+		void *handle, void *cookie)
+{
+	assert(intr_raw == CSS_CPU_PWR_DOWN_REQ_INTR);
+
+	/* Deactivate warm reboot SGI */
+	plat_ic_end_of_interrupt(CSS_CPU_PWR_DOWN_REQ_INTR);
+
+	/*
+	 * Disable GIC CPU interface to prevent pending interrupt from waking
+	 * up the AP from WFI.
+	 */
+	plat_arm_gic_cpuif_disable();
+	plat_arm_gic_redistif_off();
+
+	psci_pwrdown_cpu(PLAT_MAX_PWR_LVL);
+
+	dmbsy();
+
+	wfi();
+	return 0;
+}
+
+/*******************************************************************************
+ * Export the platform handlers via plat_arm_psci_pm_ops. The ARM Standard
+ * platform will take care of registering the handlers with PSCI.
+ ******************************************************************************/
+plat_psci_ops_t plat_arm_psci_pm_ops = {
+	.pwr_domain_on		= css_pwr_domain_on,
+	.pwr_domain_on_finish	= css_pwr_domain_on_finish,
+	.pwr_domain_on_finish_late = css_pwr_domain_on_finish_late,
+	.pwr_domain_off		= css_pwr_domain_off,
+	.cpu_standby		= css_cpu_standby,
+	.pwr_domain_suspend	= css_pwr_domain_suspend,
+	.pwr_domain_suspend_finish	= css_pwr_domain_suspend_finish,
+	.system_off		= css_system_off,
+	.system_reset		= css_system_reset,
+	.validate_power_state	= css_validate_power_state,
+	.validate_ns_entrypoint = arm_validate_psci_entrypoint,
+	.translate_power_state_by_mpidr = css_translate_power_state_by_mpidr,
+	.get_node_hw_state	= css_node_hw_state,
+	.get_sys_suspend_power_state = css_get_sys_suspend_power_state,
+
+#if defined(PLAT_ARM_MEM_PROT_ADDR)
+	.mem_protect_chk	= arm_psci_mem_protect_chk,
+	.read_mem_protect	= arm_psci_read_mem_protect,
+	.write_mem_protect	= arm_nor_psci_write_mem_protect,
+#endif
+#if CSS_USE_SCMI_SDS_DRIVER
+	.system_reset2		= css_system_reset2,
+#endif
+};
diff --git a/plat/arm/css/common/css_topology.c b/plat/arm/css/common/css_topology.c
new file mode 100644
index 0000000..8aca744
--- /dev/null
+++ b/plat/arm/css/common/css_topology.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <plat/arm/common/plat_arm.h>
+#include <plat/common/platform.h>
+
+#if ARM_PLAT_MT
+#pragma weak plat_arm_get_cpu_pe_count
+#endif
+
+/******************************************************************************
+ * This function implements a part of the critical interface between the psci
+ * generic layer and the platform that allows the former to query the platform
+ * to convert an MPIDR to a unique linear index. An error code (-1) is
+ * returned in case the MPIDR is invalid.
+ *****************************************************************************/
+int plat_core_pos_by_mpidr(u_register_t mpidr)
+{
+	if (arm_check_mpidr(mpidr) == 0) {
+#if ARM_PLAT_MT
+		assert((read_mpidr_el1() & MPIDR_MT_MASK) != 0);
+
+		/*
+		 * The DTB files don't provide the MT bit in the mpidr argument
+		 * so set it manually before calculating core position
+		 */
+		mpidr |= MPIDR_MT_MASK;
+#endif
+		return plat_arm_calc_core_pos(mpidr);
+	}
+	return -1;
+}
+
+#if ARM_PLAT_MT
+/******************************************************************************
+ * This function returns the PE count within the physical cpu corresponding to
+ * `mpidr`. Now one cpu only have one thread, so just return 1.
+ *****************************************************************************/
+unsigned int plat_arm_get_cpu_pe_count(u_register_t mpidr)
+{
+	return 1;
+}
+#endif /* ARM_PLAT_MT */
diff --git a/plat/arm/css/common/sp_min/css_sp_min.mk b/plat/arm/css/common/sp_min/css_sp_min.mk
new file mode 100644
index 0000000..ae489fd
--- /dev/null
+++ b/plat/arm/css/common/sp_min/css_sp_min.mk
@@ -0,0 +1,22 @@
+#
+# Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# SP MIN source files common to CSS platforms
+BL32_SOURCES		+=	plat/arm/css/common/css_pm.c			\
+				plat/arm/css/common/css_topology.c
+
+ifeq (${CSS_USE_SCMI_SDS_DRIVER},0)
+BL32_SOURCES		+=	drivers/arm/css/mhu/css_mhu.c			\
+				drivers/arm/css/scp/css_pm_scpi.c		\
+				drivers/arm/css/scpi/css_scpi.c
+else
+BL32_SOURCES		+=	drivers/arm/css/mhu/css_mhu_doorbell.c		\
+				drivers/arm/css/scp/css_pm_scmi.c		\
+				drivers/delay_timer/delay_timer.c		\
+				drivers/arm/css/scmi/scmi_common.c		\
+				drivers/arm/css/scmi/scmi_pwr_dmn_proto.c	\
+				drivers/arm/css/scmi/scmi_sys_pwr_proto.c
+endif
diff --git a/plat/arm/css/sgi/aarch64/sgi_helper.S b/plat/arm/css/sgi/aarch64/sgi_helper.S
new file mode 100644
index 0000000..ced59e8
--- /dev/null
+++ b/plat/arm/css/sgi/aarch64/sgi_helper.S
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <platform_def.h>
+#include <cortex_a75.h>
+#include <neoverse_n1.h>
+#include <neoverse_v1.h>
+#include <neoverse_n2.h>
+#include <cpu_macros.S>
+
+	.globl	plat_arm_calc_core_pos
+	.globl	plat_reset_handler
+
+	/* -----------------------------------------------------
+	 * unsigned int plat_arm_calc_core_pos(u_register_t mpidr)
+	 *
+	 * Helper function to calculate the core position.
+	 * (ChipId * PLAT_ARM_CLUSTER_COUNT *
+	 *  CSS_SGI_MAX_CPUS_PER_CLUSTER * CSS_SGI_MAX_PE_PER_CPU) +
+	 * (ClusterId * CSS_SGI_MAX_CPUS_PER_CLUSTER * CSS_SGI_MAX_PE_PER_CPU) +
+	 * (CPUId * CSS_SGI_MAX_PE_PER_CPU) +
+	 * ThreadId
+	 *
+	 * which can be simplified as:
+	 *
+	 * ((((ChipId * PLAT_ARM_CLUSTER_COUNT) + ClusterId) *
+	 *   CSS_SGI_MAX_CPUS_PER_CLUSTER) + CPUId) * CSS_SGI_MAX_PE_PER_CPU +
+	 * ThreadId
+	 * ------------------------------------------------------
+	 */
+
+func plat_arm_calc_core_pos
+	mov	x4, x0
+
+	/*
+	 * The MT bit in MPIDR is always set for SGI platforms
+	 * and the affinity level 0 corresponds to thread affinity level.
+	 */
+
+	/* Extract individual affinity fields from MPIDR */
+	ubfx    x0, x4, #MPIDR_AFF0_SHIFT, #MPIDR_AFFINITY_BITS
+	ubfx    x1, x4, #MPIDR_AFF1_SHIFT, #MPIDR_AFFINITY_BITS
+	ubfx    x2, x4, #MPIDR_AFF2_SHIFT, #MPIDR_AFFINITY_BITS
+	ubfx    x3, x4, #MPIDR_AFF3_SHIFT, #MPIDR_AFFINITY_BITS
+
+	/* Compute linear position */
+	mov     x4, #PLAT_ARM_CLUSTER_COUNT
+	madd    x2, x3, x4, x2
+	mov     x4, #CSS_SGI_MAX_CPUS_PER_CLUSTER
+	madd    x1, x2, x4, x1
+	mov     x4, #CSS_SGI_MAX_PE_PER_CPU
+	madd    x0, x1, x4, x0
+	ret
+endfunc plat_arm_calc_core_pos
+
+	/* -----------------------------------------------------
+	 * void plat_reset_handler(void);
+	 *
+	 * Determine the CPU MIDR and disable power down bit for
+	 * that CPU.
+	 * -----------------------------------------------------
+	 */
+func plat_reset_handler
+	jump_if_cpu_midr CORTEX_A75_MIDR, A75
+	jump_if_cpu_midr NEOVERSE_N1_MIDR, N1
+	jump_if_cpu_midr NEOVERSE_V1_MIDR, V1
+	jump_if_cpu_midr NEOVERSE_N2_MIDR, N2
+	ret
+
+	/* -----------------------------------------------------
+	 * Disable CPU power down bit in power control register
+	 * -----------------------------------------------------
+	 */
+A75:
+	mrs	x0, CORTEX_A75_CPUPWRCTLR_EL1
+	bic	x0, x0, #CORTEX_A75_CORE_PWRDN_EN_MASK
+	msr	CORTEX_A75_CPUPWRCTLR_EL1, x0
+	isb
+	ret
+
+N1:
+	mrs	x0, NEOVERSE_N1_CPUPWRCTLR_EL1
+	bic	x0, x0, #NEOVERSE_N1_CORE_PWRDN_EN_MASK
+	msr	NEOVERSE_N1_CPUPWRCTLR_EL1, x0
+	isb
+	ret
+
+V1:
+	mrs	x0, NEOVERSE_V1_CPUPWRCTLR_EL1
+	bic	x0, x0, #NEOVERSE_V1_CPUPWRCTLR_EL1_CORE_PWRDN_BIT
+	msr	NEOVERSE_V1_CPUPWRCTLR_EL1, x0
+	isb
+	ret
+
+N2:
+	mrs	x0, NEOVERSE_N2_CPUPWRCTLR_EL1
+	bic	x0, x0, #NEOVERSE_N2_CORE_PWRDN_EN_BIT
+	msr	NEOVERSE_N2_CPUPWRCTLR_EL1, x0
+	isb
+	ret
+endfunc plat_reset_handler
diff --git a/plat/arm/css/sgi/include/plat_macros.S b/plat/arm/css/sgi/include/plat_macros.S
new file mode 100644
index 0000000..521bcc3
--- /dev/null
+++ b/plat/arm/css/sgi/include/plat_macros.S
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef PLAT_MACROS_S
+#define PLAT_MACROS_S
+
+#include <css_macros.S>
+
+/* ---------------------------------------------
+ * The below required platform porting macro
+ * prints out relevant platform registers
+ * whenever an unhandled exception is taken in
+ * BL31.
+ *
+ * There are currently no platform specific regs
+ * to print.
+ * ---------------------------------------------
+ */
+	.macro plat_crash_print_regs
+	.endm
+
+#endif /* PLAT_MACROS_S */
diff --git a/plat/arm/css/sgi/include/sgi_base_platform_def.h b/plat/arm/css/sgi/include/sgi_base_platform_def.h
new file mode 100644
index 0000000..c1fadc6
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_base_platform_def.h
@@ -0,0 +1,300 @@
+/*
+ * Copyright (c) 2018-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_BASE_PLATFORM_DEF_H
+#define SGI_BASE_PLATFORM_DEF_H
+
+#include <lib/utils_def.h>
+#include <lib/xlat_tables/xlat_tables_defs.h>
+#include <plat/arm/common/arm_def.h>
+#include <plat/arm/common/arm_spm_def.h>
+#include <plat/arm/css/common/css_def.h>
+#include <plat/common/common_def.h>
+
+#define PLATFORM_CORE_COUNT		(CSS_SGI_CHIP_COUNT *		\
+					PLAT_ARM_CLUSTER_COUNT *	\
+					CSS_SGI_MAX_CPUS_PER_CLUSTER *	\
+					CSS_SGI_MAX_PE_PER_CPU)
+
+#define PLAT_ARM_TRUSTED_SRAM_SIZE	0x00080000	/* 512 KB */
+
+/* Remote chip address offset */
+#define CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n)	\
+		((ULL(1) << CSS_SGI_ADDR_BITS_PER_CHIP) * (n))
+
+/*
+ * PLAT_ARM_MMAP_ENTRIES depends on the number of entries in the
+ * plat_arm_mmap array defined for each BL stage. In addition to that, on
+ * multi-chip platforms, address regions on each of the remote chips are
+ * also mapped. In BL31, for instance, three address regions on the remote
+ * chips are accessed - secure ram, css device and soc device regions.
+ */
+#if defined(IMAGE_BL31)
+# if SPM_MM
+#  define PLAT_ARM_MMAP_ENTRIES		(9  + ((CSS_SGI_CHIP_COUNT - 1) * 3))
+#  define MAX_XLAT_TABLES		(7  + ((CSS_SGI_CHIP_COUNT - 1) * 3))
+#  define PLAT_SP_IMAGE_MMAP_REGIONS	10
+#  define PLAT_SP_IMAGE_MAX_XLAT_TABLES	12
+# else
+#  define PLAT_ARM_MMAP_ENTRIES		(5 + ((CSS_SGI_CHIP_COUNT - 1) * 3))
+#  define MAX_XLAT_TABLES		(6 + ((CSS_SGI_CHIP_COUNT - 1) * 3))
+# endif
+#elif defined(IMAGE_BL32)
+# define PLAT_ARM_MMAP_ENTRIES		8
+# define MAX_XLAT_TABLES		5
+#elif defined(IMAGE_BL2)
+# define PLAT_ARM_MMAP_ENTRIES		(11 + (CSS_SGI_CHIP_COUNT - 1))
+
+/*
+ * MAX_XLAT_TABLES entries need to be doubled because when the address width
+ * exceeds 40 bits an additional level of translation is required. In case of
+ * multichip platforms peripherals also fall into address space with width
+ * > 40 bits
+ *
+ */
+# define MAX_XLAT_TABLES		(7  + ((CSS_SGI_CHIP_COUNT - 1) * 2))
+#elif !USE_ROMLIB
+# define PLAT_ARM_MMAP_ENTRIES		11
+# define MAX_XLAT_TABLES		7
+#else
+# define PLAT_ARM_MMAP_ENTRIES		12
+# define MAX_XLAT_TABLES		6
+#endif
+
+/*
+ * PLAT_ARM_MAX_BL1_RW_SIZE is calculated using the current BL1 RW debug size
+ * plus a little space for growth.
+ */
+#define PLAT_ARM_MAX_BL1_RW_SIZE	(64 * 1024)	/* 64 KB */
+
+/*
+ * PLAT_ARM_MAX_ROMLIB_RW_SIZE is define to use a full page
+ */
+
+#if USE_ROMLIB
+#define PLAT_ARM_MAX_ROMLIB_RW_SIZE	0x1000
+#define PLAT_ARM_MAX_ROMLIB_RO_SIZE	0xe000
+#else
+#define PLAT_ARM_MAX_ROMLIB_RW_SIZE	0
+#define PLAT_ARM_MAX_ROMLIB_RO_SIZE	0
+#endif
+
+/*
+ * PLAT_ARM_MAX_BL2_SIZE is calculated using the current BL2 debug size plus a
+ * little space for growth. Additional 8KiB space is added per chip in
+ * order to accommodate the additional level of translation required for "TZC"
+ * peripheral access which lies in >4TB address space.
+ *
+ */
+#if TRUSTED_BOARD_BOOT
+# define PLAT_ARM_MAX_BL2_SIZE		(0x20000 + ((CSS_SGI_CHIP_COUNT - 1) * \
+							0x2000))
+#else
+# define PLAT_ARM_MAX_BL2_SIZE		(0x14000 + ((CSS_SGI_CHIP_COUNT - 1) * \
+							0x2000))
+#endif
+
+/*
+ * Since BL31 NOBITS overlays BL2 and BL1-RW, PLAT_ARM_MAX_BL31_SIZE is
+ * calculated using the current BL31 PROGBITS debug size plus the sizes of BL2
+ * and BL1-RW. CSS_SGI_BL31_SIZE - is tuned with respect to the actual BL31
+ * PROGBITS size which is around 64-68KB at the time this change is being made.
+ * A buffer of ~35KB is added to account for future expansion of the image,
+ * making it a total of 100KB.
+ */
+#define CSS_SGI_BL31_SIZE		(100 * 1024)	/* 100 KB */
+#define PLAT_ARM_MAX_BL31_SIZE		(CSS_SGI_BL31_SIZE +		\
+						PLAT_ARM_MAX_BL2_SIZE +	\
+						PLAT_ARM_MAX_BL1_RW_SIZE)
+
+/*
+ * Size of cacheable stacks
+ */
+#if defined(IMAGE_BL1)
+# if TRUSTED_BOARD_BOOT
+#  define PLATFORM_STACK_SIZE 0x1000
+# else
+#  define PLATFORM_STACK_SIZE 0x440
+# endif
+#elif defined(IMAGE_BL2)
+# if TRUSTED_BOARD_BOOT
+#  define PLATFORM_STACK_SIZE 0x1000
+# else
+#  define PLATFORM_STACK_SIZE 0x400
+# endif
+#elif defined(IMAGE_BL2U)
+# define PLATFORM_STACK_SIZE 0x400
+#elif defined(IMAGE_BL31)
+# if SPM_MM
+#  define PLATFORM_STACK_SIZE 0x500
+# else
+#  define PLATFORM_STACK_SIZE 0x400
+# endif
+#elif defined(IMAGE_BL32)
+# define PLATFORM_STACK_SIZE 0x440
+#endif
+
+/* PL011 UART related constants */
+#define SOC_CSS_SEC_UART_BASE			UL(0x2A410000)
+#define SOC_CSS_NSEC_UART_BASE			UL(0x2A400000)
+#define SOC_CSS_UART_SIZE			UL(0x10000)
+#define SOC_CSS_UART_CLK_IN_HZ			UL(7372800)
+
+/* UART related constants */
+#define PLAT_ARM_BOOT_UART_BASE			SOC_CSS_SEC_UART_BASE
+#define PLAT_ARM_BOOT_UART_CLK_IN_HZ		SOC_CSS_UART_CLK_IN_HZ
+
+#define PLAT_ARM_RUN_UART_BASE			SOC_CSS_SEC_UART_BASE
+#define PLAT_ARM_RUN_UART_CLK_IN_HZ		SOC_CSS_UART_CLK_IN_HZ
+
+#define PLAT_ARM_CRASH_UART_BASE		SOC_CSS_SEC_UART_BASE
+#define PLAT_ARM_CRASH_UART_CLK_IN_HZ		SOC_CSS_UART_CLK_IN_HZ
+
+#define PLAT_ARM_NSTIMER_FRAME_ID	0
+
+#define PLAT_ARM_TRUSTED_ROM_BASE	0x0
+#define PLAT_ARM_TRUSTED_ROM_SIZE	0x00080000	/* 512KB */
+
+#define PLAT_ARM_NSRAM_BASE		0x06000000
+#define PLAT_ARM_NSRAM_SIZE		0x00080000	/* 512KB */
+
+#define PLAT_ARM_DRAM2_BASE		ULL(0x8080000000)
+#define PLAT_ARM_DRAM2_SIZE		ULL(0x180000000)
+
+#define PLAT_ARM_G1S_IRQ_PROPS(grp)	CSS_G1S_IRQ_PROPS(grp)
+#define PLAT_ARM_G0_IRQ_PROPS(grp)	ARM_G0_IRQ_PROPS(grp)
+
+#define CSS_SGI_DEVICE_BASE	(0x20000000)
+#define CSS_SGI_DEVICE_SIZE	(0x20000000)
+#define CSS_SGI_MAP_DEVICE	MAP_REGION_FLAT(		\
+					CSS_SGI_DEVICE_BASE,	\
+					CSS_SGI_DEVICE_SIZE,	\
+					MT_DEVICE | MT_RW | MT_SECURE)
+
+#define ARM_MAP_SHARED_RAM_REMOTE_CHIP(n)					\
+			MAP_REGION_FLAT(					\
+				CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) +		\
+				ARM_SHARED_RAM_BASE,				\
+				ARM_SHARED_RAM_SIZE,				\
+				MT_NON_CACHEABLE | MT_RW | MT_SECURE		\
+			)
+
+#define CSS_SGI_MAP_DEVICE_REMOTE_CHIP(n)					\
+			MAP_REGION_FLAT(					\
+				CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) +		\
+				CSS_SGI_DEVICE_BASE,				\
+				CSS_SGI_DEVICE_SIZE,				\
+				MT_DEVICE | MT_RW | MT_SECURE			\
+			)
+
+#define SOC_CSS_MAP_DEVICE_REMOTE_CHIP(n)					\
+			MAP_REGION_FLAT(					\
+				CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) +		\
+				SOC_CSS_DEVICE_BASE,				\
+				SOC_CSS_DEVICE_SIZE,				\
+				MT_DEVICE | MT_RW | MT_SECURE			\
+			)
+
+/* Map the secure region for access from S-EL0 */
+#define PLAT_ARM_SECURE_MAP_DEVICE	MAP_REGION_FLAT(	\
+					SOC_CSS_DEVICE_BASE,	\
+					SOC_CSS_DEVICE_SIZE,	\
+					MT_DEVICE | MT_RW | MT_SECURE | MT_USER)
+
+#define PLAT_SP_PRI				PLAT_RAS_PRI
+
+#if SPM_MM && RAS_EXTENSION
+/*
+ * CPER buffer memory of 128KB is reserved and it is placed adjacent to the
+ * memory shared between EL3 and S-EL0.
+ */
+#define CSS_SGI_SP_CPER_BUF_BASE	(PLAT_SP_IMAGE_NS_BUF_BASE + \
+					 PLAT_SP_IMAGE_NS_BUF_SIZE)
+#define CSS_SGI_SP_CPER_BUF_SIZE	ULL(0x20000)
+#define CSS_SGI_SP_CPER_BUF_MMAP	MAP_REGION2(			       \
+						CSS_SGI_SP_CPER_BUF_BASE,      \
+						CSS_SGI_SP_CPER_BUF_BASE,      \
+						CSS_SGI_SP_CPER_BUF_SIZE,      \
+						MT_RW_DATA | MT_NS | MT_USER,  \
+						PAGE_SIZE)
+
+/*
+ * Secure partition stack follows right after the memory space reserved for
+ * CPER buffer memory.
+ */
+#define PLAT_ARM_SP_IMAGE_STACK_BASE		(PLAT_SP_IMAGE_NS_BUF_BASE +   \
+						 PLAT_SP_IMAGE_NS_BUF_SIZE +   \
+						 CSS_SGI_SP_CPER_BUF_SIZE)
+#elif SPM_MM
+/*
+ * Secure partition stack follows right after the memory region that is shared
+ * between EL3 and S-EL0.
+ */
+#define PLAT_ARM_SP_IMAGE_STACK_BASE	(PLAT_SP_IMAGE_NS_BUF_BASE +	\
+					 PLAT_SP_IMAGE_NS_BUF_SIZE)
+#endif /* SPM_MM && RAS_EXTENSION */
+
+/* Platform ID address */
+#define SSC_VERSION                     (SSC_REG_BASE + SSC_VERSION_OFFSET)
+#ifndef __ASSEMBLER__
+/* SSC_VERSION related accessors */
+/* Returns the part number of the platform */
+#define GET_SGI_PART_NUM                                       \
+		GET_SSC_VERSION_PART_NUM(mmio_read_32(SSC_VERSION))
+/* Returns the configuration number of the platform */
+#define GET_SGI_CONFIG_NUM                                     \
+		GET_SSC_VERSION_CONFIG(mmio_read_32(SSC_VERSION))
+#endif /* __ASSEMBLER__ */
+
+/*******************************************************************************
+ * Memprotect definitions
+ ******************************************************************************/
+/* PSCI memory protect definitions:
+ * This variable is stored in a non-secure flash because some ARM reference
+ * platforms do not have secure NVRAM. Real systems that provided MEM_PROTECT
+ * support must use a secure NVRAM to store the PSCI MEM_PROTECT definitions.
+ */
+#define PLAT_ARM_MEM_PROT_ADDR		(V2M_FLASH0_BASE + \
+					 V2M_FLASH0_SIZE - V2M_FLASH_BLOCK_SIZE)
+
+/*Secure Watchdog Constants */
+#define SBSA_SECURE_WDOG_BASE		UL(0x2A480000)
+#define SBSA_SECURE_WDOG_TIMEOUT	UL(100)
+
+/* Number of SCMI channels on the platform */
+#define PLAT_ARM_SCMI_CHANNEL_COUNT	CSS_SGI_CHIP_COUNT
+
+/*
+ * Mapping definition of the TrustZone Controller for ARM SGI/RD platforms
+ * where both the DRAM regions are marked for non-secure access. This applies
+ * to multi-chip platforms.
+ */
+#define SGI_PLAT_TZC_NS_REMOTE_REGIONS_DEF(n)				\
+	{CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) + ARM_DRAM1_BASE,		\
+		CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) + ARM_DRAM1_END,	\
+		ARM_TZC_NS_DRAM_S_ACCESS, PLAT_ARM_TZC_NS_DEV_ACCESS},	\
+	{CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) + ARM_DRAM2_BASE,		\
+		CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) + ARM_DRAM2_END,	\
+		ARM_TZC_NS_DRAM_S_ACCESS, PLAT_ARM_TZC_NS_DEV_ACCESS}
+
+#if SPM_MM
+
+/*
+ * Stand-alone MM logs would be routed via secure UART. Define page table
+ * entry for secure UART which would be common to all platforms.
+ */
+#define SOC_PLATFORM_SECURE_UART	MAP_REGION_FLAT(		\
+					SOC_CSS_SEC_UART_BASE,		\
+					SOC_CSS_UART_SIZE,		\
+					MT_DEVICE | MT_RW | 		\
+					MT_SECURE | MT_USER)
+
+#endif
+
+/* SDS ID for unusable CPU MPID list structure */
+#define SDS_ISOLATED_CPU_LIST_ID		U(128)
+
+#endif /* SGI_BASE_PLATFORM_DEF_H */
diff --git a/plat/arm/css/sgi/include/sgi_dmc620_tzc_regions.h b/plat/arm/css/sgi/include/sgi_dmc620_tzc_regions.h
new file mode 100644
index 0000000..e939163
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_dmc620_tzc_regions.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_DMC620_TZC_REGIONS_H
+#define SGI_DMC620_TZC_REGIONS_H
+
+#include <drivers/arm/tzc_dmc620.h>
+
+#if SPM_MM
+#define CSS_SGI_DMC620_TZC_REGIONS_DEF				\
+	{							\
+		.region_base = ARM_AP_TZC_DRAM1_BASE,		\
+		.region_top = PLAT_SP_IMAGE_NS_BUF_BASE - 1,	\
+		.sec_attr = TZC_DMC620_REGION_S_RDWR		\
+	}, {							\
+		.region_base = PLAT_SP_IMAGE_NS_BUF_BASE,	\
+		.region_top = PLAT_ARM_SP_IMAGE_STACK_BASE - 1,	\
+		.sec_attr = TZC_DMC620_REGION_S_NS_RDWR		\
+	}, {							\
+		.region_base = PLAT_ARM_SP_IMAGE_STACK_BASE,	\
+		.region_top = ARM_AP_TZC_DRAM1_END,		\
+		.sec_attr = TZC_DMC620_REGION_S_RDWR		\
+	}
+#else
+#define CSS_SGI_DMC620_TZC_REGIONS_DEF				\
+	{							\
+		.region_base = ARM_AP_TZC_DRAM1_BASE,		\
+		.region_top = ARM_AP_TZC_DRAM1_END,		\
+		.sec_attr = TZC_DMC620_REGION_S_RDWR		\
+	}
+#endif /* SPM_MM */
+
+#endif /* SGI_DMC620_TZC_REGIONS_H */
diff --git a/plat/arm/css/sgi/include/sgi_plat.h b/plat/arm/css/sgi/include/sgi_plat.h
new file mode 100644
index 0000000..a5fbded
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_plat.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_PLAT_H
+#define SGI_PLAT_H
+
+/* BL31 platform setup common to all SGI based platforms */
+void sgi_bl31_common_platform_setup(void);
+
+#endif /* SGI_PLAT_H */
diff --git a/plat/arm/css/sgi/include/sgi_ras.h b/plat/arm/css/sgi/include/sgi_ras.h
new file mode 100644
index 0000000..e69a684
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_ras.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2018-2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_RAS_H
+#define SGI_RAS_H
+
+/*
+ * Mapping the RAS interrupt with SDEI event number and the event
+ * id used with Standalone MM code
+ */
+struct sgi_ras_ev_map {
+	int sdei_ev_num;	/* SDEI Event number */
+	int intr;		/* Physical intr number */
+};
+
+int sgi_ras_intr_handler_setup(void);
+
+#endif /* SGI_RAS_H */
diff --git a/plat/arm/css/sgi/include/sgi_sdei.h b/plat/arm/css/sgi/include/sgi_sdei.h
new file mode 100644
index 0000000..f380122
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_sdei.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_SDEI_H
+#define SGI_SDEI_H
+
+#if SDEI_SUPPORT
+
+/* ARM SDEI dynamic shared event numbers */
+#define SGI_SDEI_DS_EVENT_0		U(804)
+#define SGI_SDEI_DS_EVENT_1		U(805)
+
+#define PLAT_ARM_PRIVATE_SDEI_EVENTS					      \
+		SDEI_DEFINE_EVENT_0(ARM_SDEI_SGI),			      \
+		SDEI_EXPLICIT_EVENT(SGI_SDEI_DS_EVENT_0, SDEI_MAPF_CRITICAL), \
+		SDEI_EXPLICIT_EVENT(SGI_SDEI_DS_EVENT_1, SDEI_MAPF_CRITICAL),
+
+#define PLAT_ARM_SHARED_SDEI_EVENTS
+
+#endif /* SDEI_SUPPORT */
+
+#endif /* SGI_SDEI_H */
diff --git a/plat/arm/css/sgi/include/sgi_soc_css_def.h b/plat/arm/css/sgi/include/sgi_soc_css_def.h
new file mode 100644
index 0000000..f78b45a
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_soc_css_def.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_SOC_CSS_DEF_H
+#define SGI_SOC_CSS_DEF_H
+
+#include <lib/utils_def.h>
+#include <plat/arm/board/common/v2m_def.h>
+#include <plat/arm/soc/common/soc_css_def.h>
+#include <plat/common/common_def.h>
+
+/*
+ * Definitions common to all ARM CSSv1-based development platforms
+ */
+
+/* Platform ID address */
+#define BOARD_CSS_PLAT_ID_REG_ADDR		UL(0x7ffe00e0)
+
+/* Platform ID related accessors */
+#define BOARD_CSS_PLAT_ID_REG_ID_MASK		0x0f
+#define BOARD_CSS_PLAT_ID_REG_ID_SHIFT		0x0
+#define BOARD_CSS_PLAT_TYPE_EMULATOR		0x02
+
+#ifndef __ASSEMBLER__
+
+#include <lib/mmio.h>
+
+#define BOARD_CSS_GET_PLAT_TYPE(addr)					\
+	((mmio_read_32(addr) & BOARD_CSS_PLAT_ID_REG_ID_MASK)		\
+	>> BOARD_CSS_PLAT_ID_REG_ID_SHIFT)
+
+#endif /* __ASSEMBLER__ */
+
+#define MAX_IO_DEVICES			3
+#define MAX_IO_HANDLES			4
+
+/* Reserve the last block of flash for PSCI MEM PROTECT flag */
+#define PLAT_ARM_FLASH_IMAGE_BASE	V2M_FLASH0_BASE
+#define PLAT_ARM_FLASH_IMAGE_MAX_SIZE	(V2M_FLASH0_SIZE - V2M_FLASH_BLOCK_SIZE)
+
+#define PLAT_ARM_NVM_BASE		V2M_FLASH0_BASE
+#define PLAT_ARM_NVM_SIZE		(V2M_FLASH0_SIZE - V2M_FLASH_BLOCK_SIZE)
+
+#endif /* SGI_SOC_CSS_DEF_H */
diff --git a/plat/arm/css/sgi/include/sgi_soc_css_def_v2.h b/plat/arm/css/sgi/include/sgi_soc_css_def_v2.h
new file mode 100644
index 0000000..acf31eb
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_soc_css_def_v2.h
@@ -0,0 +1,202 @@
+/*
+ * Copyright (c) 2021-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_SOC_CSS_DEF_V2_H
+#define SGI_SOC_CSS_DEF_V2_H
+
+#include <lib/utils_def.h>
+#include <plat/common/common_def.h>
+
+/*
+ * Definitions common to all ARM CSS SoCs
+ */
+
+/* Following covers ARM CSS SoC Peripherals */
+
+#define SOC_SYSTEM_PERIPH_BASE		UL(0x0C000000)
+#define SOC_SYSTEM_PERIPH_SIZE		UL(0x02000000)
+
+#define SOC_PLATFORM_PERIPH_BASE	UL(0x0E000000)
+#define SOC_PLATFORM_PERIPH_SIZE	UL(0x02000000)
+
+#define SOC_CSS_PCIE_CONTROL_BASE	UL(0x0ef20000)
+
+/* Memory controller */
+#define SOC_MEMCNTRL_BASE		UL(0x10000000)
+#define SOC_MEMCNTRL_SIZE		UL(0x10000000)
+
+/* SoC NIC-400 Global Programmers View (GPV) */
+#define SOC_CSS_NIC400_BASE		UL(0x0ED00000)
+
+#define SOC_CSS_NIC400_USB_EHCI		U(0)
+#define SOC_CSS_NIC400_TLX_MASTER	U(1)
+#define SOC_CSS_NIC400_USB_OHCI		U(2)
+#define SOC_CSS_NIC400_PL354_SMC	U(3)
+/*
+ * The apb4_bridge controls access to:
+ *   - the PCIe configuration registers
+ *   - the MMU units for USB, HDLCD and DMA
+ */
+#define SOC_CSS_NIC400_APB4_BRIDGE	U(4)
+
+/* Non-volatile counters */
+#define SOC_TRUSTED_NVCTR_BASE		UL(0x0EE70000)
+#define TFW_NVCTR_BASE			(SOC_TRUSTED_NVCTR_BASE + 0x0000)
+#define TFW_NVCTR_SIZE			U(4)
+#define NTFW_CTR_BASE			(SOC_TRUSTED_NVCTR_BASE + 0x0004)
+#define NTFW_CTR_SIZE			U(4)
+
+/* Keys */
+#define SOC_KEYS_BASE			UL(0x0EE80000)
+#define TZ_PUB_KEY_HASH_BASE		(SOC_KEYS_BASE + 0x0000)
+#define TZ_PUB_KEY_HASH_SIZE		U(32)
+#define HU_KEY_BASE			(SOC_KEYS_BASE + 0x0020)
+#define HU_KEY_SIZE			U(16)
+#define END_KEY_BASE			(SOC_KEYS_BASE + 0x0044)
+#define END_KEY_SIZE			U(32)
+
+#define SOC_PLATFORM_PERIPH_MAP_DEVICE	MAP_REGION_FLAT(			\
+						SOC_PLATFORM_PERIPH_BASE, 	\
+						SOC_PLATFORM_PERIPH_SIZE, 	\
+						MT_DEVICE | MT_RW | MT_SECURE)
+
+#if SPM_MM
+/*
+ * Memory map definition for the platform peripheral memory region that is
+ * accessible from S-EL0 (with secure user mode access).
+ */
+#define SOC_PLATFORM_PERIPH_MAP_DEVICE_USER				       \
+		MAP_REGION_FLAT(					       \
+			SOC_PLATFORM_PERIPH_BASE,			       \
+			SOC_PLATFORM_PERIPH_SIZE,			       \
+			MT_DEVICE | MT_RW | MT_SECURE | MT_USER)
+#endif
+
+#define SOC_SYSTEM_PERIPH_MAP_DEVICE	MAP_REGION_FLAT(			\
+						SOC_SYSTEM_PERIPH_BASE,		\
+						SOC_SYSTEM_PERIPH_SIZE,		\
+						MT_DEVICE | MT_RW | MT_SECURE)
+
+#define SOC_MEMCNTRL_MAP_DEVICE		MAP_REGION_FLAT(			\
+						SOC_MEMCNTRL_BASE,		\
+						SOC_MEMCNTRL_SIZE,		\
+						MT_DEVICE | MT_RW | MT_SECURE)
+
+#define SOC_MEMCNTRL_MAP_DEVICE_REMOTE_CHIP(n)					\
+		MAP_REGION_FLAT(						\
+			CSS_SGI_REMOTE_CHIP_MEM_OFFSET(n) + SOC_MEMCNTRL_BASE,	\
+			SOC_MEMCNTRL_SIZE,					\
+			MT_DEVICE | MT_RW | MT_SECURE)
+
+/*
+ * The bootsec_bridge controls access to a bunch of peripherals, e.g. the UARTs.
+ */
+#define SOC_CSS_NIC400_BOOTSEC_BRIDGE		U(5)
+#define SOC_CSS_NIC400_BOOTSEC_BRIDGE_UART1	UL(1 << 12)
+
+/*
+ * Required platform porting definitions common to all ARM CSS SoCs
+ */
+/* 2MB used for SCP DDR retraining */
+#define PLAT_ARM_SCP_TZC_DRAM1_SIZE	UL(0x00200000)
+
+/* V2M motherboard system registers & offsets */
+#define V2M_SYSREGS_BASE		UL(0x0C010000)
+#define V2M_SYS_LED			U(0x8)
+
+/*
+ * V2M sysled bit definitions. The values written to this
+ * register are defined in arch.h & runtime_svc.h. Only
+ * used by the primary cpu to diagnose any cold boot issues.
+ *
+ * SYS_LED[0]   - Security state (S=0/NS=1)
+ * SYS_LED[2:1] - Exception Level (EL3-EL0)
+ * SYS_LED[7:3] - Exception Class (Sync/Async & origin)
+ *
+ */
+#define V2M_SYS_LED_SS_SHIFT		U(0)
+#define V2M_SYS_LED_EL_SHIFT		U(1)
+#define V2M_SYS_LED_EC_SHIFT		U(3)
+
+#define V2M_SYS_LED_SS_MASK		U(0x01)
+#define V2M_SYS_LED_EL_MASK		U(0x03)
+#define V2M_SYS_LED_EC_MASK		U(0x1f)
+
+/* NOR Flash */
+#define V2M_FLASH0_BASE			UL(0x08000000)
+#define V2M_FLASH0_SIZE			UL(0x04000000)
+#define V2M_FLASH_BLOCK_SIZE		UL(0x00040000)	/* 256 KB */
+
+/*
+ * The flash can be mapped either as read-only or read-write.
+ *
+ * If it is read-write then it should also be mapped as device memory because
+ * NOR flash programming involves sending a fixed, ordered sequence of commands.
+ *
+ * If it is read-only then it should also be mapped as:
+ * - Normal memory, because reading from NOR flash is transparent, it is like
+ *   reading from RAM.
+ * - Non-executable by default. If some parts of the flash need to be executable
+ *   then platform code is responsible for re-mapping the appropriate portion
+ *   of it as executable.
+ */
+#define V2M_MAP_FLASH0_RW		MAP_REGION_FLAT(V2M_FLASH0_BASE,\
+						V2M_FLASH0_SIZE,	\
+						MT_DEVICE | MT_RW | MT_SECURE)
+
+#define V2M_MAP_FLASH0_RO		MAP_REGION_FLAT(V2M_FLASH0_BASE,\
+						V2M_FLASH0_SIZE,	\
+						MT_RO_DATA | MT_SECURE)
+
+#define SGI_MAP_FLASH0_RO		MAP_REGION_FLAT(V2M_FLASH0_BASE,\
+						V2M_FLASH0_SIZE,	\
+						MT_DEVICE | MT_RO | MT_SECURE)
+
+/* Platform ID address */
+#define BOARD_CSS_PLAT_ID_REG_ADDR		UL(0x0EFE00E0)
+
+/* Platform ID related accessors */
+#define BOARD_CSS_PLAT_ID_REG_ID_MASK		U(0x0F)
+#define BOARD_CSS_PLAT_ID_REG_ID_SHIFT		U(0x00)
+#define BOARD_CSS_PLAT_ID_REG_VERSION_MASK	U(0xF00)
+#define BOARD_CSS_PLAT_ID_REG_VERSION_SHIFT	U(0x08)
+#define BOARD_CSS_PLAT_TYPE_RTL			U(0x00)
+#define BOARD_CSS_PLAT_TYPE_FPGA		U(0x01)
+#define BOARD_CSS_PLAT_TYPE_EMULATOR		U(0x02)
+#define BOARD_CSS_PLAT_TYPE_FVP			U(0x03)
+
+#ifndef __ASSEMBLER__
+
+#include <lib/mmio.h>
+
+#define BOARD_CSS_GET_PLAT_TYPE(addr)					\
+	((mmio_read_32(addr) & BOARD_CSS_PLAT_ID_REG_ID_MASK)		\
+	>> BOARD_CSS_PLAT_ID_REG_ID_SHIFT)
+
+#endif /* __ASSEMBLER__ */
+
+
+#define MAX_IO_DEVICES			U(3)
+#define MAX_IO_HANDLES			U(4)
+
+/* Reserve the last block of flash for PSCI MEM PROTECT flag */
+#define PLAT_ARM_FLASH_IMAGE_BASE	V2M_FLASH0_BASE
+#define PLAT_ARM_FLASH_IMAGE_MAX_SIZE	(V2M_FLASH0_SIZE - V2M_FLASH_BLOCK_SIZE)
+
+#if ARM_GPT_SUPPORT
+/*
+ * Offset of the FIP in the GPT image. BL1 component uses this option
+ * as it does not load the partition table to get the FIP base
+ * address. At sector 34 by default (i.e. after reserved sectors 0-33)
+ * Offset = 34 * 512(sector size) = 17408 i.e. 0x4400
+ */
+#define PLAT_ARM_FIP_OFFSET_IN_GPT		0x4400
+#endif /* ARM_GPT_SUPPORT */
+
+#define PLAT_ARM_NVM_BASE		V2M_FLASH0_BASE
+#define PLAT_ARM_NVM_SIZE		(V2M_FLASH0_SIZE - V2M_FLASH_BLOCK_SIZE)
+
+#endif /* SGI_SOC_CSS_DEF_V2_H */
diff --git a/plat/arm/css/sgi/include/sgi_soc_platform_def.h b/plat/arm/css/sgi/include/sgi_soc_platform_def.h
new file mode 100644
index 0000000..3b8d9c6
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_soc_platform_def.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2020-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_SOC_PLATFORM_DEF_H
+#define SGI_SOC_PLATFORM_DEF_H
+
+#include <plat/arm/board/common/v2m_def.h>
+#include <plat/arm/soc/common/soc_css_def.h>
+#include <sgi_base_platform_def.h>
+#include <sgi_soc_css_def.h>
+
+/* Map the System registers to access from S-EL0 */
+#define CSS_SYSTEMREG_DEVICE_BASE	(0x1C010000)
+#define CSS_SYSTEMREG_DEVICE_SIZE	(0x00010000)
+#define PLAT_ARM_SECURE_MAP_SYSTEMREG	MAP_REGION_FLAT(		    \
+						CSS_SYSTEMREG_DEVICE_BASE,  \
+						CSS_SYSTEMREG_DEVICE_SIZE,  \
+						(MT_DEVICE | MT_RW |	    \
+						 MT_SECURE | MT_USER))
+
+/* Map the NOR2 Flash to access from S-EL0 */
+#define CSS_NOR2_FLASH_DEVICE_BASE	(0x10000000)
+#define CSS_NOR2_FLASH_DEVICE_SIZE	(0x04000000)
+#define PLAT_ARM_SECURE_MAP_NOR2	MAP_REGION_FLAT(                    \
+						CSS_NOR2_FLASH_DEVICE_BASE, \
+						CSS_NOR2_FLASH_DEVICE_SIZE, \
+						(MT_DEVICE | MT_RW |	    \
+						 MT_SECURE | MT_USER))
+
+#endif /* SGI_SOC_PLATFORM_DEF_H */
diff --git a/plat/arm/css/sgi/include/sgi_soc_platform_def_v2.h b/plat/arm/css/sgi/include/sgi_soc_platform_def_v2.h
new file mode 100644
index 0000000..20dd682
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_soc_platform_def_v2.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2020-2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_SOC_PLATFORM_DEF_V2_H
+#define SGI_SOC_PLATFORM_DEF_V2_H
+
+#include <sgi_base_platform_def.h>
+#include <sgi_soc_css_def_v2.h>
+
+/* Map the System registers to access from S-EL0 */
+#define CSS_SYSTEMREG_DEVICE_BASE	(0x0C010000)
+#define CSS_SYSTEMREG_DEVICE_SIZE	(0x00010000)
+#define PLAT_ARM_SECURE_MAP_SYSTEMREG	MAP_REGION_FLAT(                    \
+						CSS_SYSTEMREG_DEVICE_BASE,  \
+						CSS_SYSTEMREG_DEVICE_SIZE,  \
+						(MT_DEVICE | MT_RW |	    \
+						 MT_SECURE | MT_USER))
+
+/* Map the NOR2 Flash to access from S-EL0 */
+#define CSS_NOR2_FLASH_DEVICE_BASE	(0x001054000000)
+#define CSS_NOR2_FLASH_DEVICE_SIZE	(0x000004000000)
+#define PLAT_ARM_SECURE_MAP_NOR2	MAP_REGION_FLAT(                    \
+						CSS_NOR2_FLASH_DEVICE_BASE, \
+						CSS_NOR2_FLASH_DEVICE_SIZE, \
+						(MT_DEVICE | MT_RW |	    \
+						 MT_SECURE | MT_USER))
+
+#endif /* SGI_SOC_PLATFORM_DEF_V2_H */
diff --git a/plat/arm/css/sgi/include/sgi_variant.h b/plat/arm/css/sgi/include/sgi_variant.h
new file mode 100644
index 0000000..223ac3e
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_variant.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2018-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SGI_VARIANT_H
+#define SGI_VARIANT_H
+
+/* SSC_VERSION values for SGI575 */
+#define SGI575_SSC_VER_PART_NUM			0x0783
+
+/* SID Version values for RD-N1E1-Edge */
+#define RD_N1E1_EDGE_SID_VER_PART_NUM		0x0786
+#define RD_E1_EDGE_CONFIG_ID			0x2
+
+/* SID Version values for RD-V1 */
+#define RD_V1_SID_VER_PART_NUM			0x078a
+
+/* SID Version values for RD-N2 */
+#define RD_N2_SID_VER_PART_NUM			0x07B7
+
+/* SID Version values for RD-N2 variants */
+#define RD_N2_CFG1_SID_VER_PART_NUM		0x07B6
+
+/* SID Version values for RD-V2 */
+#define RD_V2_SID_VER_PART_NUM			0x07F2
+#define RD_V2_CONFIG_ID				0x1
+
+/* Structure containing SGI platform variant information */
+typedef struct sgi_platform_info {
+	unsigned int platform_id;	/* Part Number of the platform */
+	unsigned int config_id;		/* Config Id of the platform */
+	unsigned int chip_id;		/* Chip Id or Node number */
+	unsigned int multi_chip_mode;	/* Multi-chip mode availability */
+} sgi_platform_info_t;
+
+extern sgi_platform_info_t sgi_plat_info;
+
+/* returns the part number of the platform*/
+unsigned int plat_arm_sgi_get_platform_id(void);
+
+/* returns the configuration id of the platform */
+unsigned int plat_arm_sgi_get_config_id(void);
+
+/* returns true if operating in multi-chip configuration */
+unsigned int plat_arm_sgi_get_multi_chip_mode(void);
+
+#endif /* SGI_VARIANT_H */
diff --git a/plat/arm/css/sgi/sgi-common.mk b/plat/arm/css/sgi/sgi-common.mk
new file mode 100644
index 0000000..282a5f0
--- /dev/null
+++ b/plat/arm/css/sgi/sgi-common.mk
@@ -0,0 +1,86 @@
+#
+# Copyright (c) 2018-2022, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+CSS_USE_SCMI_SDS_DRIVER		:=	1
+
+CSS_ENT_BASE			:=	plat/arm/css/sgi
+
+RAS_EXTENSION			:=	0
+
+SDEI_SUPPORT			:=	0
+
+EL3_EXCEPTION_HANDLING		:=	0
+
+HANDLE_EA_EL3_FIRST_NS		:=	0
+
+CSS_SGI_CHIP_COUNT		:=	1
+
+CSS_SGI_PLATFORM_VARIANT	:=	0
+
+# Do not enable SVE
+ENABLE_SVE_FOR_NS		:=	0
+
+CTX_INCLUDE_FPREGS		:=	1
+
+INTERCONNECT_SOURCES	:=	${CSS_ENT_BASE}/sgi_interconnect.c
+
+PLAT_INCLUDES		+=	-I${CSS_ENT_BASE}/include
+
+# GIC-600 configuration
+GICV3_SUPPORT_GIC600	:=	1
+
+# Include GICv3 driver files
+include drivers/arm/gic/v3/gicv3.mk
+
+ENT_GIC_SOURCES		:=	${GICV3_SOURCES}		\
+				plat/common/plat_gicv3.c	\
+				plat/arm/common/arm_gicv3.c
+
+PLAT_BL_COMMON_SOURCES	+=	${CSS_ENT_BASE}/aarch64/sgi_helper.S
+
+BL1_SOURCES		+=	${INTERCONNECT_SOURCES}			\
+				drivers/arm/sbsa/sbsa.c
+
+BL2_SOURCES		+=	${CSS_ENT_BASE}/sgi_image_load.c	\
+				drivers/arm/css/sds/sds.c
+
+BL31_SOURCES		+=	${INTERCONNECT_SOURCES}			\
+				${ENT_GIC_SOURCES}			\
+				${CSS_ENT_BASE}/sgi_bl31_setup.c	\
+				${CSS_ENT_BASE}/sgi_topology.c
+
+ifeq (${RAS_EXTENSION},1)
+BL31_SOURCES		+=	${CSS_ENT_BASE}/sgi_ras.c
+endif
+
+ifneq (${RESET_TO_BL31},0)
+  $(error "Using BL31 as the reset vector is not supported on ${PLAT} platform. \
+  Please set RESET_TO_BL31 to 0.")
+endif
+
+$(eval $(call add_define,SGI_PLAT))
+
+$(eval $(call add_define,CSS_SGI_CHIP_COUNT))
+
+$(eval $(call add_define,CSS_SGI_PLATFORM_VARIANT))
+
+override CSS_LOAD_SCP_IMAGES	:=	0
+override NEED_BL2U		:=	no
+override ARM_PLAT_MT		:=	1
+override PSCI_EXTENDED_STATE_ID	:=	1
+override ARM_RECOM_STATE_ID_ENC	:=	1
+
+# System coherency is managed in hardware
+HW_ASSISTED_COHERENCY	:=	1
+
+# When building for systems with hardware-assisted coherency, there's no need to
+# use USE_COHERENT_MEM. Require that USE_COHERENT_MEM must be set to 0 too.
+USE_COHERENT_MEM	:=	0
+
+include plat/arm/common/arm_common.mk
+include plat/arm/css/common/css_common.mk
+include plat/arm/soc/common/soc_css.mk
+include plat/arm/board/common/board_common.mk
diff --git a/plat/arm/css/sgi/sgi_bl31_setup.c b/plat/arm/css/sgi/sgi_bl31_setup.c
new file mode 100644
index 0000000..27cf183
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_bl31_setup.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2018-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <libfdt.h>
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <drivers/arm/css/css_mhu_doorbell.h>
+#include <drivers/arm/css/scmi.h>
+#include <plat/arm/common/plat_arm.h>
+
+#include <plat/common/platform.h>
+
+#include <plat/arm/css/common/css_pm.h>
+
+#include <sgi_ras.h>
+#include <sgi_variant.h>
+
+sgi_platform_info_t sgi_plat_info;
+
+static scmi_channel_plat_info_t sgi575_scmi_plat_info = {
+		.scmi_mbx_mem = CSS_SCMI_PAYLOAD_BASE,
+		.db_reg_addr = PLAT_CSS_MHU_BASE + CSS_SCMI_MHU_DB_REG_OFF,
+		.db_preserve_mask = 0xfffffffe,
+		.db_modify_mask = 0x1,
+		.ring_doorbell = &mhu_ring_doorbell,
+};
+
+static scmi_channel_plat_info_t plat_rd_scmi_info[] = {
+	{
+		.scmi_mbx_mem = CSS_SCMI_PAYLOAD_BASE,
+		.db_reg_addr = PLAT_CSS_MHU_BASE + SENDER_REG_SET(0),
+		.db_preserve_mask = 0xfffffffe,
+		.db_modify_mask = 0x1,
+		.ring_doorbell = &mhuv2_ring_doorbell,
+	},
+	#if (CSS_SGI_CHIP_COUNT > 1)
+	{
+		.scmi_mbx_mem = CSS_SCMI_PAYLOAD_BASE +
+			CSS_SGI_REMOTE_CHIP_MEM_OFFSET(1),
+		.db_reg_addr = PLAT_CSS_MHU_BASE
+			+ CSS_SGI_REMOTE_CHIP_MEM_OFFSET(1) + SENDER_REG_SET(0),
+		.db_preserve_mask = 0xfffffffe,
+		.db_modify_mask = 0x1,
+		.ring_doorbell = &mhuv2_ring_doorbell,
+	},
+	#endif
+	#if (CSS_SGI_CHIP_COUNT > 2)
+	{
+		.scmi_mbx_mem = CSS_SCMI_PAYLOAD_BASE +
+			CSS_SGI_REMOTE_CHIP_MEM_OFFSET(2),
+		.db_reg_addr = PLAT_CSS_MHU_BASE +
+			CSS_SGI_REMOTE_CHIP_MEM_OFFSET(2) + SENDER_REG_SET(0),
+		.db_preserve_mask = 0xfffffffe,
+		.db_modify_mask = 0x1,
+		.ring_doorbell = &mhuv2_ring_doorbell,
+	},
+	#endif
+	#if (CSS_SGI_CHIP_COUNT > 3)
+	{
+		.scmi_mbx_mem = CSS_SCMI_PAYLOAD_BASE +
+			CSS_SGI_REMOTE_CHIP_MEM_OFFSET(3),
+		.db_reg_addr = PLAT_CSS_MHU_BASE +
+			CSS_SGI_REMOTE_CHIP_MEM_OFFSET(3) + SENDER_REG_SET(0),
+		.db_preserve_mask = 0xfffffffe,
+		.db_modify_mask = 0x1,
+		.ring_doorbell = &mhuv2_ring_doorbell,
+	},
+	#endif
+};
+
+scmi_channel_plat_info_t *plat_css_get_scmi_info(int channel_id)
+{
+	if (sgi_plat_info.platform_id == RD_N1E1_EDGE_SID_VER_PART_NUM ||
+		sgi_plat_info.platform_id == RD_V1_SID_VER_PART_NUM ||
+		sgi_plat_info.platform_id == RD_N2_SID_VER_PART_NUM ||
+		sgi_plat_info.platform_id == RD_V2_SID_VER_PART_NUM ||
+		sgi_plat_info.platform_id == RD_N2_CFG1_SID_VER_PART_NUM) {
+		if (channel_id >= ARRAY_SIZE(plat_rd_scmi_info))
+			panic();
+		return &plat_rd_scmi_info[channel_id];
+	}
+	else if (sgi_plat_info.platform_id == SGI575_SSC_VER_PART_NUM)
+		return &sgi575_scmi_plat_info;
+	else
+		panic();
+}
+
+void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+				u_register_t arg2, u_register_t arg3)
+{
+	sgi_plat_info.platform_id = plat_arm_sgi_get_platform_id();
+	sgi_plat_info.config_id = plat_arm_sgi_get_config_id();
+	sgi_plat_info.multi_chip_mode = plat_arm_sgi_get_multi_chip_mode();
+
+	arm_bl31_early_platform_setup((void *)arg0, arg1, arg2, (void *)arg3);
+}
+
+void sgi_bl31_common_platform_setup(void)
+{
+	arm_bl31_platform_setup();
+
+#if RAS_EXTENSION
+	sgi_ras_intr_handler_setup();
+#endif
+
+	/* Configure the warm reboot SGI for primary core */
+	css_setup_cpu_pwr_down_intr();
+
+#if CSS_SYSTEM_GRACEFUL_RESET
+	/* Register priority level handlers for reboot */
+	ehf_register_priority_handler(PLAT_REBOOT_PRI,
+			css_reboot_interrupt_handler);
+#endif
+}
+
+const plat_psci_ops_t *plat_arm_psci_override_pm_ops(plat_psci_ops_t *ops)
+{
+	/*
+	 * For RD-E1-Edge, only CPU power ON/OFF, PSCI platform callbacks are
+	 * supported.
+	 */
+	if (((sgi_plat_info.platform_id == RD_N1E1_EDGE_SID_VER_PART_NUM) &&
+	    (sgi_plat_info.config_id == RD_E1_EDGE_CONFIG_ID))) {
+		ops->cpu_standby = NULL;
+		ops->system_off = NULL;
+		ops->system_reset = NULL;
+		ops->get_sys_suspend_power_state = NULL;
+		ops->pwr_domain_suspend = NULL;
+		ops->pwr_domain_suspend_finish = NULL;
+	}
+
+	return css_scmi_override_pm_ops(ops);
+}
diff --git a/plat/arm/css/sgi/sgi_image_load.c b/plat/arm/css/sgi/sgi_image_load.c
new file mode 100644
index 0000000..ac4bfd2
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_image_load.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2018-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <libfdt.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <common/desc_image_load.h>
+#include <drivers/arm/css/sds.h>
+#include <plat/arm/common/plat_arm.h>
+#include <plat/common/platform.h>
+
+#include <platform_def.h>
+#include <sgi_base_platform_def.h>
+#include <sgi_variant.h>
+
+/*
+ * Information about the isolated CPUs obtained from SDS.
+ */
+struct isolated_cpu_mpid_list {
+	uint64_t num_entries; /* Number of entries in the list */
+	uint64_t mpid_list[PLATFORM_CORE_COUNT]; /* List of isolated CPU MPIDs */
+};
+
+/* Function to read isolated CPU MPID list from SDS. */
+void plat_arm_sgi_get_isolated_cpu_list(struct isolated_cpu_mpid_list *list)
+{
+	int ret;
+
+	ret = sds_init();
+	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,
+			sizeof(list->num_entries), SDS_ACCESS_MODE_CACHED);
+	if (ret != SDS_OK) {
+		INFO("SDS CPU num elements read failed, error: %d\n", ret);
+		list->num_entries = 0;
+		return;
+	}
+
+	if (list->num_entries > PLATFORM_CORE_COUNT) {
+		ERROR("Isolated CPU list count %ld greater than max"
+		      " number supported %d\n",
+		      list->num_entries, PLATFORM_CORE_COUNT);
+		panic();
+	} else if (list->num_entries == 0) {
+		INFO("SDS isolated CPU list is empty\n");
+		return;
+	}
+
+	ret = sds_struct_read(SDS_ISOLATED_CPU_LIST_ID,
+			sizeof(list->num_entries),
+			&list->mpid_list,
+			sizeof(list->mpid_list[0]) * list->num_entries,
+			SDS_ACCESS_MODE_CACHED);
+	if (ret != SDS_OK) {
+		ERROR("SDS CPU list read failed. error: %d\n", ret);
+		panic();
+	}
+}
+
+/*******************************************************************************
+ * This function inserts Platform information via device tree nodes as,
+ * system-id {
+ *    platform-id = <0>;
+ *    config-id = <0>;
+ *    isolated-cpu-list = <0>
+ * }
+ ******************************************************************************/
+static int plat_sgi_append_config_node(void)
+{
+	bl_mem_params_node_t *mem_params;
+	void *fdt;
+	int nodeoffset, err;
+	unsigned int platid = 0, platcfg = 0;
+	struct isolated_cpu_mpid_list cpu_mpid_list = {0};
+
+	mem_params = get_bl_mem_params_node(NT_FW_CONFIG_ID);
+	if (mem_params == NULL) {
+		ERROR("NT_FW CONFIG base address is NULL");
+		return -1;
+	}
+
+	fdt = (void *)(mem_params->image_info.image_base);
+
+	/* Check the validity of the fdt */
+	if (fdt_check_header(fdt) != 0) {
+		ERROR("Invalid NT_FW_CONFIG DTB passed\n");
+		return -1;
+	}
+
+	nodeoffset = fdt_subnode_offset(fdt, 0, "system-id");
+	if (nodeoffset < 0) {
+		ERROR("Failed to get system-id node offset\n");
+		return -1;
+	}
+
+	platid = plat_arm_sgi_get_platform_id();
+	err = fdt_setprop_u32(fdt, nodeoffset, "platform-id", platid);
+	if (err < 0) {
+		ERROR("Failed to set platform-id\n");
+		return -1;
+	}
+
+	platcfg = plat_arm_sgi_get_config_id();
+	err = fdt_setprop_u32(fdt, nodeoffset, "config-id", platcfg);
+	if (err < 0) {
+		ERROR("Failed to set config-id\n");
+		return -1;
+	}
+
+	platcfg = plat_arm_sgi_get_multi_chip_mode();
+	err = fdt_setprop_u32(fdt, nodeoffset, "multi-chip-mode", platcfg);
+	if (err < 0) {
+		ERROR("Failed to set multi-chip-mode\n");
+		return -1;
+	}
+
+	plat_arm_sgi_get_isolated_cpu_list(&cpu_mpid_list);
+	if (cpu_mpid_list.num_entries > 0) {
+		err = fdt_setprop(fdt, nodeoffset, "isolated-cpu-list",
+				&cpu_mpid_list,
+				(sizeof(cpu_mpid_list.num_entries) *
+				(cpu_mpid_list.num_entries + 1)));
+		if (err < 0) {
+			ERROR("Failed to set isolated-cpu-list, error: %d\n",
+			      err);
+		}
+	}
+
+	flush_dcache_range((uintptr_t)fdt, mem_params->image_info.image_size);
+
+	return 0;
+}
+
+/*******************************************************************************
+ * This function returns the list of executable images.
+ ******************************************************************************/
+bl_params_t *plat_get_next_bl_params(void)
+{
+	int ret;
+
+	ret = plat_sgi_append_config_node();
+	if (ret != 0)
+		panic();
+
+	return arm_get_next_bl_params();
+}
+
diff --git a/plat/arm/css/sgi/sgi_interconnect.c b/plat/arm/css/sgi/sgi_interconnect.c
new file mode 100644
index 0000000..e9cd812
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_interconnect.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <plat/arm/common/plat_arm.h>
+
+/*
+ * For SGI575 which support FCM (with automatic interconnect enter/exit),
+ * we should not do anything in these interface functions.
+ * They are used to override the weak functions in cci drivers.
+ */
+
+/******************************************************************************
+ * Helper function to initialize ARM interconnect driver.
+ *****************************************************************************/
+void __init plat_arm_interconnect_init(void)
+{
+}
+
+/******************************************************************************
+ * Helper function to place current master into coherency
+ *****************************************************************************/
+void plat_arm_interconnect_enter_coherency(void)
+{
+}
+
+/******************************************************************************
+ * Helper function to remove current master from coherency
+ *****************************************************************************/
+void plat_arm_interconnect_exit_coherency(void)
+{
+}
diff --git a/plat/arm/css/sgi/sgi_plat.c b/plat/arm/css/sgi/sgi_plat.c
new file mode 100644
index 0000000..a0199c3
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_plat.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 2018-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <platform_def.h>
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <drivers/arm/ccn.h>
+#include <plat/arm/common/plat_arm.h>
+#include <plat/common/platform.h>
+#include <drivers/arm/sbsa.h>
+#include <sgi_base_platform_def.h>
+
+#if SPM_MM
+#include <services/spm_mm_partition.h>
+#endif
+
+#define SGI_MAP_FLASH0_RO	MAP_REGION_FLAT(V2M_FLASH0_BASE,\
+						V2M_FLASH0_SIZE,	\
+						MT_DEVICE | MT_RO | MT_SECURE)
+/*
+ * Table of regions for different BL stages to map using the MMU.
+ * This doesn't include Trusted RAM as the 'mem_layout' argument passed to
+ * arm_configure_mmu_elx() will give the available subset of that.
+ *
+ * Replace or extend the below regions as required
+ */
+#if IMAGE_BL1
+const mmap_region_t plat_arm_mmap[] = {
+	ARM_MAP_SHARED_RAM,
+	SGI_MAP_FLASH0_RO,
+	CSS_SGI_MAP_DEVICE,
+	SOC_CSS_MAP_DEVICE,
+	{0}
+};
+#endif
+#if IMAGE_BL2
+const mmap_region_t plat_arm_mmap[] = {
+	ARM_MAP_SHARED_RAM,
+	SGI_MAP_FLASH0_RO,
+#ifdef PLAT_ARM_MEM_PROT_ADDR
+	ARM_V2M_MAP_MEM_PROTECT,
+#endif
+	CSS_SGI_MAP_DEVICE,
+	SOC_CSS_MAP_DEVICE,
+	ARM_MAP_NS_DRAM1,
+#if CSS_SGI_CHIP_COUNT > 1
+	CSS_SGI_MAP_DEVICE_REMOTE_CHIP(1),
+#endif
+#if CSS_SGI_CHIP_COUNT > 2
+	CSS_SGI_MAP_DEVICE_REMOTE_CHIP(2),
+#endif
+#if CSS_SGI_CHIP_COUNT > 3
+	CSS_SGI_MAP_DEVICE_REMOTE_CHIP(3),
+#endif
+#if ARM_BL31_IN_DRAM
+	ARM_MAP_BL31_SEC_DRAM,
+#endif
+#if SPM_MM
+	ARM_SP_IMAGE_MMAP,
+#endif
+#if TRUSTED_BOARD_BOOT && !BL2_AT_EL3
+	ARM_MAP_BL1_RW,
+#endif
+	{0}
+};
+#endif
+#if IMAGE_BL31
+const mmap_region_t plat_arm_mmap[] = {
+	ARM_MAP_SHARED_RAM,
+	V2M_MAP_IOFPGA,
+	CSS_SGI_MAP_DEVICE,
+#ifdef PLAT_ARM_MEM_PROT_ADDR
+	ARM_V2M_MAP_MEM_PROTECT,
+#endif
+	SOC_CSS_MAP_DEVICE,
+#if SPM_MM
+	ARM_SPM_BUF_EL3_MMAP,
+#endif
+	{0}
+};
+
+#if SPM_MM && defined(IMAGE_BL31)
+const mmap_region_t plat_arm_secure_partition_mmap[] = {
+	PLAT_ARM_SECURE_MAP_SYSTEMREG,
+	PLAT_ARM_SECURE_MAP_NOR2,
+	SOC_PLATFORM_SECURE_UART,
+	PLAT_ARM_SECURE_MAP_DEVICE,
+	ARM_SP_IMAGE_MMAP,
+	ARM_SP_IMAGE_NS_BUF_MMAP,
+#if RAS_EXTENSION
+	CSS_SGI_SP_CPER_BUF_MMAP,
+#endif
+	ARM_SP_IMAGE_RW_MMAP,
+	ARM_SPM_BUF_EL0_MMAP,
+	{0}
+};
+#endif /* SPM_MM && defined(IMAGE_BL31) */
+#endif
+
+ARM_CASSERT_MMAP
+
+#if SPM_MM && defined(IMAGE_BL31)
+/*
+ * Boot information passed to a secure partition during initialisation. Linear
+ * indices in MP information will be filled at runtime.
+ */
+static spm_mm_mp_info_t sp_mp_info[] = {
+	[0] = {0x81000000, 0},
+	[1] = {0x81000100, 0},
+	[2] = {0x81000200, 0},
+	[3] = {0x81000300, 0},
+	[4] = {0x81010000, 0},
+	[5] = {0x81010100, 0},
+	[6] = {0x81010200, 0},
+	[7] = {0x81010300, 0},
+};
+
+const spm_mm_boot_info_t plat_arm_secure_partition_boot_info = {
+	.h.type              = PARAM_SP_IMAGE_BOOT_INFO,
+	.h.version           = VERSION_1,
+	.h.size              = sizeof(spm_mm_boot_info_t),
+	.h.attr              = 0,
+	.sp_mem_base         = ARM_SP_IMAGE_BASE,
+	.sp_mem_limit        = ARM_SP_IMAGE_LIMIT,
+	.sp_image_base       = ARM_SP_IMAGE_BASE,
+	.sp_stack_base       = PLAT_SP_IMAGE_STACK_BASE,
+	.sp_heap_base        = ARM_SP_IMAGE_HEAP_BASE,
+	.sp_ns_comm_buf_base = PLAT_SP_IMAGE_NS_BUF_BASE,
+	.sp_shared_buf_base  = PLAT_SPM_BUF_BASE,
+	.sp_image_size       = ARM_SP_IMAGE_SIZE,
+	.sp_pcpu_stack_size  = PLAT_SP_IMAGE_STACK_PCPU_SIZE,
+	.sp_heap_size        = ARM_SP_IMAGE_HEAP_SIZE,
+	.sp_ns_comm_buf_size = PLAT_SP_IMAGE_NS_BUF_SIZE,
+	.sp_shared_buf_size  = PLAT_SPM_BUF_SIZE,
+	.num_sp_mem_regions  = ARM_SP_IMAGE_NUM_MEM_REGIONS,
+	.num_cpus            = PLATFORM_CORE_COUNT,
+	.mp_info             = &sp_mp_info[0],
+};
+
+const struct mmap_region *plat_get_secure_partition_mmap(void *cookie)
+{
+	return plat_arm_secure_partition_mmap;
+}
+
+const struct spm_mm_boot_info *plat_get_secure_partition_boot_info(
+		void *cookie)
+{
+	return &plat_arm_secure_partition_boot_info;
+}
+#endif /* SPM_MM && defined(IMAGE_BL31) */
+
+#if TRUSTED_BOARD_BOOT
+int plat_get_mbedtls_heap(void **heap_addr, size_t *heap_size)
+{
+	assert(heap_addr != NULL);
+	assert(heap_size != NULL);
+
+	return arm_get_mbedtls_heap(heap_addr, heap_size);
+}
+#endif
+
+void plat_arm_secure_wdt_start(void)
+{
+	sbsa_wdog_start(SBSA_SECURE_WDOG_BASE, SBSA_SECURE_WDOG_TIMEOUT);
+}
+
+void plat_arm_secure_wdt_stop(void)
+{
+	sbsa_wdog_stop(SBSA_SECURE_WDOG_BASE);
+}
diff --git a/plat/arm/css/sgi/sgi_plat_v2.c b/plat/arm/css/sgi/sgi_plat_v2.c
new file mode 100644
index 0000000..cef5345
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_plat_v2.c
@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2021-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <platform_def.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>
+#endif
+
+/*
+ * Table of regions for different BL stages to map using the MMU.
+ */
+#if IMAGE_BL1
+const mmap_region_t plat_arm_mmap[] = {
+	ARM_MAP_SHARED_RAM,
+	SGI_MAP_FLASH0_RO,
+	CSS_SGI_MAP_DEVICE,
+	SOC_PLATFORM_PERIPH_MAP_DEVICE,
+	SOC_SYSTEM_PERIPH_MAP_DEVICE,
+	{0}
+};
+#endif
+
+#if IMAGE_BL2
+const mmap_region_t plat_arm_mmap[] = {
+	ARM_MAP_SHARED_RAM,
+	SGI_MAP_FLASH0_RO,
+#ifdef PLAT_ARM_MEM_PROT_ADDR
+	ARM_V2M_MAP_MEM_PROTECT,
+#endif
+	CSS_SGI_MAP_DEVICE,
+	SOC_MEMCNTRL_MAP_DEVICE,
+	SOC_PLATFORM_PERIPH_MAP_DEVICE,
+	SOC_SYSTEM_PERIPH_MAP_DEVICE,
+	ARM_MAP_NS_DRAM1,
+#if CSS_SGI_CHIP_COUNT > 1
+	SOC_MEMCNTRL_MAP_DEVICE_REMOTE_CHIP(1),
+#endif
+#if CSS_SGI_CHIP_COUNT > 2
+	SOC_MEMCNTRL_MAP_DEVICE_REMOTE_CHIP(2),
+#endif
+#if CSS_SGI_CHIP_COUNT > 3
+	SOC_MEMCNTRL_MAP_DEVICE_REMOTE_CHIP(3),
+#endif
+#if ARM_BL31_IN_DRAM
+	ARM_MAP_BL31_SEC_DRAM,
+#endif
+#if SPM_MM
+	ARM_SP_IMAGE_MMAP,
+#endif
+#if TRUSTED_BOARD_BOOT && !BL2_AT_EL3
+	ARM_MAP_BL1_RW,
+#endif
+	{0}
+};
+#endif
+
+#if IMAGE_BL31
+const mmap_region_t plat_arm_mmap[] = {
+	ARM_MAP_SHARED_RAM,
+#ifdef PLAT_ARM_MEM_PROT_ADDR
+	ARM_V2M_MAP_MEM_PROTECT,
+#endif
+	CSS_SGI_MAP_DEVICE,
+	SOC_PLATFORM_PERIPH_MAP_DEVICE,
+	SOC_SYSTEM_PERIPH_MAP_DEVICE,
+#if SPM_MM
+	ARM_SPM_BUF_EL3_MMAP,
+#endif
+	{0}
+};
+
+#if SPM_MM && defined(IMAGE_BL31)
+const mmap_region_t plat_arm_secure_partition_mmap[] = {
+	PLAT_ARM_SECURE_MAP_SYSTEMREG,
+	PLAT_ARM_SECURE_MAP_NOR2,
+	SOC_PLATFORM_SECURE_UART,
+	SOC_PLATFORM_PERIPH_MAP_DEVICE_USER,
+	ARM_SP_IMAGE_MMAP,
+	ARM_SP_IMAGE_NS_BUF_MMAP,
+	ARM_SP_IMAGE_RW_MMAP,
+	ARM_SPM_BUF_EL0_MMAP,
+	{0}
+};
+#endif /* SPM_MM && defined(IMAGE_BL31) */
+#endif
+
+ARM_CASSERT_MMAP
+
+#if SPM_MM && defined(IMAGE_BL31)
+/*
+ * Boot information passed to a secure partition during initialisation. Linear
+ * indices in MP information will be filled at runtime.
+ */
+static spm_mm_mp_info_t sp_mp_info[] = {
+	[0] = {0x81000000, 0},
+	[1] = {0x81010000, 0},
+	[2] = {0x81020000, 0},
+	[3] = {0x81030000, 0},
+	[4] = {0x81040000, 0},
+	[5] = {0x81050000, 0},
+	[6] = {0x81060000, 0},
+	[7] = {0x81070000, 0},
+	[8] = {0x81080000, 0},
+	[9] = {0x81090000, 0},
+	[10] = {0x810a0000, 0},
+	[11] = {0x810b0000, 0},
+	[12] = {0x810c0000, 0},
+	[13] = {0x810d0000, 0},
+	[14] = {0x810e0000, 0},
+	[15] = {0x810f0000, 0},
+};
+
+const spm_mm_boot_info_t plat_arm_secure_partition_boot_info = {
+	.h.type              = PARAM_SP_IMAGE_BOOT_INFO,
+	.h.version           = VERSION_1,
+	.h.size              = sizeof(spm_mm_boot_info_t),
+	.h.attr              = 0,
+	.sp_mem_base         = ARM_SP_IMAGE_BASE,
+	.sp_mem_limit        = ARM_SP_IMAGE_LIMIT,
+	.sp_image_base       = ARM_SP_IMAGE_BASE,
+	.sp_stack_base       = PLAT_SP_IMAGE_STACK_BASE,
+	.sp_heap_base        = ARM_SP_IMAGE_HEAP_BASE,
+	.sp_ns_comm_buf_base = PLAT_SP_IMAGE_NS_BUF_BASE,
+	.sp_shared_buf_base  = PLAT_SPM_BUF_BASE,
+	.sp_image_size       = ARM_SP_IMAGE_SIZE,
+	.sp_pcpu_stack_size  = PLAT_SP_IMAGE_STACK_PCPU_SIZE,
+	.sp_heap_size        = ARM_SP_IMAGE_HEAP_SIZE,
+	.sp_ns_comm_buf_size = PLAT_SP_IMAGE_NS_BUF_SIZE,
+	.sp_shared_buf_size  = PLAT_SPM_BUF_SIZE,
+	.num_sp_mem_regions  = ARM_SP_IMAGE_NUM_MEM_REGIONS,
+	.num_cpus            = PLATFORM_CORE_COUNT,
+	.mp_info             = &sp_mp_info[0],
+};
+
+const struct mmap_region *plat_get_secure_partition_mmap(void *cookie)
+{
+	return plat_arm_secure_partition_mmap;
+}
+
+const struct spm_mm_boot_info *plat_get_secure_partition_boot_info(
+		void *cookie)
+{
+	return &plat_arm_secure_partition_boot_info;
+}
+#endif /* SPM_MM && defined(IMAGE_BL31) */
+
+#if TRUSTED_BOARD_BOOT
+int plat_get_mbedtls_heap(void **heap_addr, size_t *heap_size)
+{
+	assert(heap_addr != NULL);
+	assert(heap_size != NULL);
+
+	return arm_get_mbedtls_heap(heap_addr, heap_size);
+}
+#endif
+
+void plat_arm_secure_wdt_start(void)
+{
+	sbsa_wdog_start(SBSA_SECURE_WDOG_BASE, SBSA_SECURE_WDOG_TIMEOUT);
+}
+
+void plat_arm_secure_wdt_stop(void)
+{
+	sbsa_wdog_stop(SBSA_SECURE_WDOG_BASE);
+}
diff --git a/plat/arm/css/sgi/sgi_ras.c b/plat/arm/css/sgi/sgi_ras.c
new file mode 100644
index 0000000..4f03ac4
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_ras.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2018-2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <string.h>
+
+#include <bl31/interrupt_mgmt.h>
+#include <lib/el3_runtime/context_mgmt.h>
+#include <lib/extensions/ras.h>
+#include <plat/arm/common/arm_spm_def.h>
+#include <plat/common/platform.h>
+#include <services/sdei.h>
+#include <services/spm_mm_svc.h>
+
+#include <sgi_ras.h>
+
+static int sgi_ras_intr_handler(const struct err_record_info *err_rec,
+				int probe_data,
+				const struct err_handler_data *const data);
+typedef struct mm_communicate_header {
+	struct efi_guid	header_guid;
+	size_t		message_len;
+	uint8_t		data[8];
+} mm_communicate_header_t;
+
+/*
+ * GUID to indicate that the MM communication message is intended for DMC-620
+ * MM driver.
+ */
+const struct efi_guid dmc620_ecc_event_guid = {
+	0x5ef0afd5, 0xe01a, 0x4c30,
+	{0x86, 0x19, 0x45, 0x46, 0x26, 0x91, 0x80, 0x98}
+};
+
+struct sgi_ras_ev_map sgi575_ras_map[] = {
+
+	/* DMC 0 error ECC error interrupt*/
+	{SGI_SDEI_DS_EVENT_0, 35},
+
+	/* DMC 1 error ECC error interrupt*/
+	{SGI_SDEI_DS_EVENT_1, 39},
+};
+
+#define SGI575_RAS_MAP_SIZE	ARRAY_SIZE(sgi575_ras_map)
+
+struct err_record_info sgi_err_records[] = {
+	{
+		/* DMC 0 error record info */
+		.handler = &sgi_ras_intr_handler,
+		.aux_data = (void *)0,
+	}, {
+		/* DMC 1 error record info */
+		.handler = &sgi_ras_intr_handler,
+		.aux_data = (void *)1,
+	},
+};
+
+struct ras_interrupt sgi_ras_interrupts[] = {
+	{
+		.intr_number = 35,
+		.err_record = &sgi_err_records[0],
+	}, {
+		.intr_number = 39,
+		.err_record = &sgi_err_records[1],
+	}
+};
+
+REGISTER_ERR_RECORD_INFO(sgi_err_records);
+REGISTER_RAS_INTERRUPTS(sgi_ras_interrupts);
+
+static struct sgi_ras_ev_map *plat_sgi_get_ras_ev_map(void)
+{
+	return sgi575_ras_map;
+}
+
+static int plat_sgi_get_ras_ev_map_size(void)
+{
+	return SGI575_RAS_MAP_SIZE;
+}
+
+/*
+ * Find event mapping for a given interrupt number: On success, returns pointer
+ * to the event mapping. On error, returns NULL.
+ */
+static struct sgi_ras_ev_map *find_ras_event_map_by_intr(uint32_t intr_num)
+{
+	struct sgi_ras_ev_map *map = plat_sgi_get_ras_ev_map();
+	int i;
+	int size = plat_sgi_get_ras_ev_map_size();
+
+	for (i = 0; i < size; i++) {
+		if (map->intr == intr_num)
+			return map;
+
+		map++;
+	}
+
+	return NULL;
+}
+
+static void sgi_ras_intr_configure(int intr)
+{
+	plat_ic_set_interrupt_type(intr, INTR_TYPE_EL3);
+	plat_ic_set_interrupt_priority(intr, PLAT_RAS_PRI);
+	plat_ic_clear_interrupt_pending(intr);
+	plat_ic_set_spi_routing(intr, INTR_ROUTING_MODE_ANY,
+				(u_register_t)read_mpidr_el1());
+	plat_ic_enable_interrupt(intr);
+}
+
+static int sgi_ras_intr_handler(const struct err_record_info *err_rec,
+				int probe_data,
+				const struct err_handler_data *const data)
+{
+	struct sgi_ras_ev_map *ras_map;
+	mm_communicate_header_t *header;
+	uint32_t intr;
+	int ret;
+
+	cm_el1_sysregs_context_save(NON_SECURE);
+	intr = data->interrupt;
+
+	/*
+	 * Find if this is a RAS interrupt. There must be an event against
+	 * this interrupt
+	 */
+	ras_map = find_ras_event_map_by_intr(intr);
+	assert(ras_map != NULL);
+
+	/*
+	 * Populate the MM_COMMUNICATE payload to share the
+	 * event info with StandaloneMM code. This allows us to use
+	 * MM_COMMUNICATE as a common entry mechanism into S-EL0. The
+	 * header data will be parsed in StandaloneMM to process the
+	 * corresponding event.
+	 *
+	 * TBD - Currently, the buffer allocated by SPM for communication
+	 * between EL3 and S-EL0 is being used(PLAT_SPM_BUF_BASE). But this
+	 * should happen via a dynamic mem allocation, which should be
+	 * managed by SPM -- the individual platforms then call the mem
+	 * alloc api to get memory for the payload.
+	 */
+	header = (void *) PLAT_SPM_BUF_BASE;
+	memset(header, 0, sizeof(*header));
+	memcpy(&header->data, &err_rec->aux_data, sizeof(err_rec->aux_data));
+	header->message_len = sizeof(err_rec->aux_data);
+	memcpy(&header->header_guid, (void *) &dmc620_ecc_event_guid,
+			sizeof(const struct efi_guid));
+
+	spm_mm_sp_call(MM_COMMUNICATE_AARCH64, (uint64_t)header, 0,
+		       plat_my_core_pos());
+
+	/*
+	 * Do an EOI of the RAS interrupt. This allows the
+	 * sdei event to be dispatched at the SDEI event's
+	 * priority.
+	 */
+	plat_ic_end_of_interrupt(intr);
+
+	/* Dispatch the event to the SDEI client */
+	ret = sdei_dispatch_event(ras_map->sdei_ev_num);
+	if (ret != 0) {
+		/*
+		 * sdei_dispatch_event() may return failing result in some cases,
+		 * for example kernel may not have registered a handler or RAS event
+		 * may happen early during boot. We restore the NS context when
+		 * sdei_dispatch_event() returns failing result.
+		 */
+		ERROR("SDEI dispatch failed: %d", ret);
+		cm_el1_sysregs_context_restore(NON_SECURE);
+		cm_set_next_eret_context(NON_SECURE);
+	}
+
+	return ret;
+}
+
+int sgi_ras_intr_handler_setup(void)
+{
+	int i;
+	struct sgi_ras_ev_map *map = plat_sgi_get_ras_ev_map();
+	int size = plat_sgi_get_ras_ev_map_size();
+
+	for (i = 0; i < size; i++) {
+		sgi_ras_intr_configure(map->intr);
+		map++;
+	}
+
+	INFO("SGI: RAS Interrupt Handler successfully registered\n");
+
+	return 0;
+}
diff --git a/plat/arm/css/sgi/sgi_topology.c b/plat/arm/css/sgi/sgi_topology.c
new file mode 100644
index 0000000..1c3b5bf
--- /dev/null
+++ b/plat/arm/css/sgi/sgi_topology.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <plat/arm/common/plat_arm.h>
+
+/*
+ * Common topology related methods for SGI and RD based platforms
+ */
+/*******************************************************************************
+ * This function returns the core count within the cluster corresponding to
+ * `mpidr`.
+ ******************************************************************************/
+unsigned int plat_arm_get_cluster_core_count(u_register_t mpidr)
+{
+	return CSS_SGI_MAX_CPUS_PER_CLUSTER;
+}
+
+#if ARM_PLAT_MT
+/******************************************************************************
+ * Return the number of PE's supported by the CPU.
+ *****************************************************************************/
+unsigned int plat_arm_get_cpu_pe_count(u_register_t mpidr)
+{
+	return CSS_SGI_MAX_PE_PER_CPU;
+}
+#endif