diff --git a/include/lib/gpt_rme/gpt_rme.h b/include/lib/gpt_rme/gpt_rme.h
new file mode 100644
index 0000000..379b915
--- /dev/null
+++ b/include/lib/gpt_rme/gpt_rme.h
@@ -0,0 +1,276 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef GPT_RME_H
+#define GPT_RME_H
+
+#include <stdint.h>
+
+#include <arch.h>
+
+/******************************************************************************/
+/* GPT helper macros and definitions                                          */
+/******************************************************************************/
+
+/*
+ * Structure for specifying a mapping range and it's properties. This should not
+ * be manually initialized, using the MAP_GPT_REGION_x macros is recommended as
+ * to avoid potential incompatibilities in the future.
+ */
+typedef struct pas_region {
+	uintptr_t	base_pa;	/* Base address for PAS. */
+	size_t		size;		/* Size of the PAS. */
+	unsigned int	attrs;		/* PAS GPI and entry type. */
+} pas_region_t;
+
+/* GPT GPI definitions */
+#define GPT_GPI_NO_ACCESS		U(0x0)
+#define GPT_GPI_SECURE			U(0x8)
+#define GPT_GPI_NS			U(0x9)
+#define GPT_GPI_ROOT			U(0xA)
+#define GPT_GPI_REALM			U(0xB)
+#define GPT_GPI_ANY			U(0xF)
+#define GPT_GPI_VAL_MASK		UL(0xF)
+
+/* PAS attribute GPI definitions. */
+#define GPT_PAS_ATTR_GPI_SHIFT		U(0)
+#define GPT_PAS_ATTR_GPI_MASK		U(0xF)
+#define GPT_PAS_ATTR_GPI(_attrs)	(((_attrs)			\
+					>> GPT_PAS_ATTR_GPI_SHIFT)	\
+					& GPT_PAS_ATTR_GPI_MASK)
+
+/* PAS attribute mapping type definitions */
+#define GPT_PAS_ATTR_MAP_TYPE_BLOCK	U(0x0)
+#define GPT_PAS_ATTR_MAP_TYPE_GRANULE	U(0x1)
+#define GPT_PAS_ATTR_MAP_TYPE_SHIFT	U(4)
+#define GPT_PAS_ATTR_MAP_TYPE_MASK	U(0x1)
+#define GPT_PAS_ATTR_MAP_TYPE(_attrs)	(((_attrs)			\
+					>> GPT_PAS_ATTR_MAP_TYPE_SHIFT)	\
+					& GPT_PAS_ATTR_MAP_TYPE_MASK)
+
+/*
+ * Macro to initialize the attributes field in the pas_region_t structure.
+ * [31:5] Reserved
+ * [4]    Mapping type (GPT_PAS_ATTR_MAP_TYPE_x definitions)
+ * [3:0]  PAS GPI type (GPT_GPI_x definitions)
+ */
+#define GPT_PAS_ATTR(_type, _gpi)					\
+	((((_type) & GPT_PAS_ATTR_MAP_TYPE_MASK)			\
+	  << GPT_PAS_ATTR_MAP_TYPE_SHIFT) |				\
+	(((_gpi) & GPT_PAS_ATTR_GPI_MASK)				\
+	 << GPT_PAS_ATTR_GPI_SHIFT))
+
+/*
+ * Macro to create a GPT entry for this PAS range as a block descriptor. If this
+ * region does not fit the requirements for a block descriptor then GPT
+ * initialization will fail.
+ */
+#define GPT_MAP_REGION_BLOCK(_pa, _sz, _gpi)				\
+	{								\
+		.base_pa = (_pa),					\
+		.size = (_sz),						\
+		.attrs = GPT_PAS_ATTR(GPT_PAS_ATTR_MAP_TYPE_BLOCK, (_gpi)), \
+	}
+
+/*
+ * Macro to create a GPT entry for this PAS range as a table descriptor. If this
+ * region does not fit the requirements for a table descriptor then GPT
+ * initialization will fail.
+ */
+#define GPT_MAP_REGION_GRANULE(_pa, _sz, _gpi)				\
+	{								\
+		.base_pa = (_pa),					\
+		.size = (_sz),						\
+		.attrs = GPT_PAS_ATTR(GPT_PAS_ATTR_MAP_TYPE_GRANULE, (_gpi)), \
+	}
+
+/******************************************************************************/
+/* GPT register field definitions                                             */
+/******************************************************************************/
+
+/*
+ * Least significant address bits protected by each entry in level 0 GPT. This
+ * field is read-only.
+ */
+#define GPCCR_L0GPTSZ_SHIFT	U(20)
+#define GPCCR_L0GPTSZ_MASK	U(0xF)
+
+typedef enum {
+	GPCCR_L0GPTSZ_30BITS	= U(0x0),
+	GPCCR_L0GPTSZ_34BITS	= U(0x4),
+	GPCCR_L0GPTSZ_36BITS	= U(0x6),
+	GPCCR_L0GPTSZ_39BITS	= U(0x9)
+} gpccr_l0gptsz_e;
+
+/* Granule protection check priority bit definitions */
+#define GPCCR_GPCP_SHIFT	U(17)
+#define GPCCR_GPCP_BIT		(ULL(1) << GPCCR_EL3_GPCP_SHIFT)
+
+/* Granule protection check bit definitions */
+#define GPCCR_GPC_SHIFT		U(16)
+#define GPCCR_GPC_BIT		(ULL(1) << GPCCR_GPC_SHIFT)
+
+/* Physical granule size bit definitions */
+#define GPCCR_PGS_SHIFT		U(14)
+#define GPCCR_PGS_MASK		U(0x3)
+#define SET_GPCCR_PGS(x)	(((x) & GPCCR_PGS_MASK) << GPCCR_PGS_SHIFT)
+
+typedef enum {
+	GPCCR_PGS_4K		= U(0x0),
+	GPCCR_PGS_64K		= U(0x1),
+	GPCCR_PGS_16K		= U(0x2)
+} gpccr_pgs_e;
+
+/* GPT fetch shareability attribute bit definitions */
+#define GPCCR_SH_SHIFT		U(12)
+#define GPCCR_SH_MASK		U(0x3)
+#define SET_GPCCR_SH(x)		(((x) & GPCCR_SH_MASK) << GPCCR_SH_SHIFT)
+
+typedef enum {
+	GPCCR_SH_NS		= U(0x0),
+	GPCCR_SH_OS		= U(0x2),
+	GPCCR_SH_IS		= U(0x3)
+} gpccr_sh_e;
+
+/* GPT fetch outer cacheability attribute bit definitions */
+#define GPCCR_ORGN_SHIFT	U(10)
+#define GPCCR_ORGN_MASK		U(0x3)
+#define SET_GPCCR_ORGN(x)	(((x) & GPCCR_ORGN_MASK) << GPCCR_ORGN_SHIFT)
+
+typedef enum {
+	GPCCR_ORGN_NC		= U(0x0),
+	GPCCR_ORGN_WB_RA_WA	= U(0x1),
+	GPCCR_ORGN_WT_RA_NWA	= U(0x2),
+	GPCCR_ORGN_WB_RA_NWA	= U(0x3)
+} gpccr_orgn_e;
+
+/* GPT fetch inner cacheability attribute bit definitions */
+#define GPCCR_IRGN_SHIFT	U(8)
+#define GPCCR_IRGN_MASK		U(0x3)
+#define SET_GPCCR_IRGN(x)	(((x) & GPCCR_IRGN_MASK) << GPCCR_IRGN_SHIFT)
+
+typedef enum {
+	GPCCR_IRGN_NC		= U(0x0),
+	GPCCR_IRGN_WB_RA_WA	= U(0x1),
+	GPCCR_IRGN_WT_RA_NWA	= U(0x2),
+	GPCCR_IRGN_WB_RA_NWA	= U(0x3)
+} gpccr_irgn_e;
+
+/* Protected physical address size bit definitions */
+#define GPCCR_PPS_SHIFT		U(0)
+#define GPCCR_PPS_MASK		U(0x7)
+#define SET_GPCCR_PPS(x)	(((x) & GPCCR_PPS_MASK) << GPCCR_PPS_SHIFT)
+
+typedef enum {
+	GPCCR_PPS_4GB		= U(0x0),
+	GPCCR_PPS_64GB		= U(0x1),
+	GPCCR_PPS_1TB		= U(0x2),
+	GPCCR_PPS_4TB		= U(0x3),
+	GPCCR_PPS_16TB		= U(0x4),
+	GPCCR_PPS_256TB		= U(0x5),
+	GPCCR_PPS_4PB		= U(0x6)
+} gpccr_pps_e;
+
+/* Base Address for the GPT bit definitions */
+#define GPTBR_BADDR_SHIFT	U(0)
+#define GPTBR_BADDR_VAL_SHIFT	U(12)
+#define GPTBR_BADDR_MASK	ULL(0xffffffffff)
+
+/******************************************************************************/
+/* GPT public APIs                                                            */
+/******************************************************************************/
+
+/*
+ * Public API that initializes the entire protected space to GPT_GPI_ANY using
+ * the L0 tables (block descriptors).  Ideally, this function is invoked prior
+ * to DDR discovery and initialization.  The MMU must be initialized before
+ * calling this function.
+ *
+ * Parameters
+ *   pps		PPS value to use for table generation
+ *   l0_mem_base	Base address of L0 tables in memory.
+ *   l0_mem_size	Total size of memory available for L0 tables.
+ *
+ * Return
+ *   Negative Linux error code in the event of a failure, 0 for success.
+ */
+int gpt_init_l0_tables(gpccr_pps_e pps,
+		       uintptr_t l0_mem_base,
+		       size_t l0_mem_size);
+
+/*
+ * Public API that carves out PAS regions from the L0 tables and builds any L1
+ * tables that are needed.  This function ideally is run after DDR discovery and
+ * initialization.  The L0 tables must have already been initialized to GPI_ANY
+ * when this function is called.
+ *
+ * Parameters
+ *   pgs		PGS value to use for table generation.
+ *   l1_mem_base	Base address of memory used for L1 tables.
+ *   l1_mem_size	Total size of memory available for L1 tables.
+ *   *pas_regions	Pointer to PAS regions structure array.
+ *   pas_count		Total number of PAS regions.
+ *
+ * Return
+ *   Negative Linux error code in the event of a failure, 0 for success.
+ */
+int gpt_init_pas_l1_tables(gpccr_pgs_e pgs,
+			   uintptr_t l1_mem_base,
+			   size_t l1_mem_size,
+			   pas_region_t *pas_regions,
+			   unsigned int pas_count);
+
+/*
+ * Public API to initialize the runtime gpt_config structure based on the values
+ * present in the GPTBR_EL3 and GPCCR_EL3 registers. GPT initialization
+ * typically happens in a bootloader stage prior to setting up the EL3 runtime
+ * environment for the granule transition service so this function detects the
+ * initialization from a previous stage. Granule protection checks must be
+ * enabled already or this function will return an error.
+ *
+ * Return
+ *   Negative Linux error code in the event of a failure, 0 for success.
+ */
+int gpt_runtime_init(void);
+
+/*
+ * Public API to enable granule protection checks once the tables have all been
+ * initialized.  This function is called at first initialization and then again
+ * later during warm boots of CPU cores.
+ *
+ * Return
+ *   Negative Linux error code in the event of a failure, 0 for success.
+ */
+int gpt_enable(void);
+
+/*
+ * Public API to disable granule protection checks.
+ */
+void gpt_disable(void);
+
+/*
+ * This function is the core of the granule transition service. When a granule
+ * transition request occurs it is routed to this function where the request is
+ * validated then fulfilled if possible.
+ *
+ * TODO: implement support for transitioning multiple granules at once.
+ *
+ * Parameters
+ *   base: Base address of the region to transition, must be aligned to granule
+ *         size.
+ *   size: Size of region to transition, must be aligned to granule size.
+ *   src_sec_state: Security state of the caller.
+ *   target_pas: Target PAS of the specified memory region.
+ *
+ * Return
+ *    Negative Linux error code in the event of a failure, 0 for success.
+ */
+int gpt_transition_pas(uint64_t base,
+		       size_t size,
+		       unsigned int src_sec_state,
+		       unsigned int target_pas);
+
+#endif /* GPT_RME_H */