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..8d3d1b9
--- /dev/null
+++ b/plat/arm/css/sgi/include/sgi_soc_css_def.h
@@ -0,0 +1,57 @@
+/*
+ * 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)
+
+/* UART related constants */
+#define PLAT_ARM_BOOT_UART_BASE			SOC_CSS_UART0_BASE
+#define PLAT_ARM_BOOT_UART_CLK_IN_HZ		SOC_CSS_UART0_CLK_IN_HZ
+
+#define PLAT_ARM_RUN_UART_BASE			SOC_CSS_UART1_BASE
+#define PLAT_ARM_RUN_UART_CLK_IN_HZ		SOC_CSS_UART1_CLK_IN_HZ
+
+#define PLAT_ARM_CRASH_UART_BASE		PLAT_ARM_RUN_UART_BASE
+#define PLAT_ARM_CRASH_UART_CLK_IN_HZ		PLAT_ARM_RUN_UART_CLK_IN_HZ
+
+#endif /* SGI_SOC_CSS_DEF_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
index 405d62f..3b8d9c6 100644
--- a/plat/arm/css/sgi/include/sgi_soc_platform_def.h
+++ b/plat/arm/css/sgi/include/sgi_soc_platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2020-2022, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,10 +7,10 @@
 #ifndef SGI_SOC_PLATFORM_DEF_H
 #define SGI_SOC_PLATFORM_DEF_H
 
-#include <sgi_base_platform_def.h>
-#include <plat/arm/board/common/board_css_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)