Adding upstream version 2.10.0+dfsg.upstream/2.10.0+dfsgupstream

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

1 files changed, 621 insertions, 0 deletions

diff --git a/drivers/arm/ccn/ccn.c b/drivers/arm/ccn/ccn.c
new file mode 100644
index 0000000..5b13250
--- /dev/null
+++ b/drivers/arm/ccn/ccn.c
@@ -0,0 +1,621 @@
+/*
+ * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+
+#include <arch.h>
+#include <common/debug.h>
+#include <drivers/arm/ccn.h>
+#include <lib/bakery_lock.h>
+#include <lib/mmio.h>
+
+#include "ccn_private.h"
+
+static const ccn_desc_t *ccn_plat_desc;
+#if defined(IMAGE_BL31) || (!defined(__aarch64__) && defined(IMAGE_BL32))
+DEFINE_BAKERY_LOCK(ccn_lock);
+#endif
+
+/*******************************************************************************
+ * This function takes the base address of the CCN's programmer's view (PV), a
+ * region ID of one of the 256 regions (0-255) and a register offset within the
+ * region. It converts the first two parameters into a base address and uses it
+ * to read the register at the offset.
+ ******************************************************************************/
+static inline unsigned long long ccn_reg_read(uintptr_t periphbase,
+			     unsigned int region_id,
+			     unsigned int register_offset)
+{
+	uintptr_t region_base;
+
+	assert(periphbase);
+	assert(region_id < REGION_ID_LIMIT);
+
+	region_base = periphbase + region_id_to_base(region_id);
+	return mmio_read_64(region_base + register_offset);
+}
+
+/*******************************************************************************
+ * This function takes the base address of the CCN's programmer's view (PV), a
+ * region ID of one of the 256 regions (0-255), a register offset within the
+ * region and a value. It converts the first two parameters into a base address
+ * and uses it to write the value in the register at the offset.
+ ******************************************************************************/
+static inline void ccn_reg_write(uintptr_t periphbase,
+			  unsigned int region_id,
+			  unsigned int register_offset,
+			  unsigned long long value)
+{
+	uintptr_t region_base;
+
+	assert(periphbase);
+	assert(region_id < REGION_ID_LIMIT);
+
+	region_base = periphbase + region_id_to_base(region_id);
+	mmio_write_64(region_base + register_offset, value);
+}
+
+#if ENABLE_ASSERTIONS
+
+typedef struct rn_info {
+		unsigned char node_desc[MAX_RN_NODES];
+	} rn_info_t;
+
+/*******************************************************************************
+ * This function takes the base address of the CCN's programmer's view (PV) and
+ * the node ID of a Request Node (RN-D or RN-I). It returns the maximum number
+ * of master interfaces resident on that node. This number is equal to the least
+ * significant two bits of the node type ID + 1.
+ ******************************************************************************/
+static unsigned int ccn_get_rni_mcount(uintptr_t periphbase,
+				       unsigned int rn_id)
+{
+	unsigned int rn_type_id;
+
+	/* Use the node id to find the type of RN-I/D node */
+	rn_type_id = get_node_type(ccn_reg_read(periphbase,
+						rn_id + RNI_REGION_ID_START,
+						REGION_ID_OFFSET));
+
+	/* Return the number master interfaces based on node type */
+	return rn_type_id_to_master_cnt(rn_type_id);
+}
+
+/*******************************************************************************
+ * This function reads the CCN registers to find the following information about
+ * the ACE/ACELite/ACELite+DVM/CHI interfaces resident on the various types of
+ * Request Nodes (RN-Fs, RN-Is and RN-Ds) in the system:
+ *
+ * 1. The total number of such interfaces that this CCN IP supports. This is the
+ *    cumulative number of interfaces across all Request node types. It is
+ *    passed back as the return value of this function.
+ *
+ * 2. The maximum number of interfaces of a type resident on a Request node of
+ *    one of the three types. This information is populated in the 'info'
+ *    array provided by the caller as described next.
+ *
+ *    The array has 64 entries. Each entry corresponds to a Request node. The
+ *    Miscellaneous node's programmer's view has RN-F, RN-I and RN-D ID
+ *    registers. For each RN-I and RN-D ID indicated as being present in these
+ *    registers, its identification register (offset 0xFF00) is read. This
+ *    register specifies the maximum number of master interfaces the node
+ *    supports. For RN-Fs it is assumed that there can be only a single fully
+ *    coherent master resident on each node. The counts for each type of node
+ *    are use to populate the array entry at the index corresponding to the node
+ *    ID i.e. rn_info[node ID] = <number of master interfaces>
+ ******************************************************************************/
+static unsigned int ccn_get_rn_master_info(uintptr_t periphbase,
+					   rn_info_t *info)
+{
+	unsigned int num_masters = 0;
+	rn_types_t rn_type;
+
+	assert (info);
+
+	for (rn_type = RN_TYPE_RNF; rn_type < NUM_RN_TYPES; rn_type++) {
+		unsigned int mn_reg_off, node_id;
+		unsigned long long rn_bitmap;
+
+		/*
+		 * RN-F, RN-I, RN-D node registers in the MN region occupy
+		 * contiguous 16 byte apart offsets.
+		 */
+		mn_reg_off = MN_RNF_NODEID_OFFSET + (rn_type << 4);
+		rn_bitmap = ccn_reg_read(periphbase, MN_REGION_ID, mn_reg_off);
+
+		FOR_EACH_PRESENT_NODE_ID(node_id, rn_bitmap) {
+			unsigned int node_mcount;
+
+			/*
+			 * A RN-F does not have a node type since it does not
+			 * export a programmer's interface. It can only have a
+			 * single fully coherent master residing on it. If the
+			 * offset of the MN(Miscellaneous Node) register points
+			 * to a RN-I/D node then the master count is set to the
+			 * maximum number of master interfaces that can possibly
+			 * reside on the node.
+			 */
+			node_mcount = (mn_reg_off == MN_RNF_NODEID_OFFSET ? 1 :
+				       ccn_get_rni_mcount(periphbase, node_id));
+
+			/*
+			 * Use this value to increment the maximum possible
+			 * master interfaces in the system.
+			 */
+			num_masters += node_mcount;
+
+			/*
+			 * Update the entry in 'info' for this node ID with
+			 * the maximum number of masters than can sit on
+			 * it. This information will be used to validate the
+			 * node information passed by the platform later.
+			 */
+			info->node_desc[node_id] = node_mcount;
+		}
+	}
+
+	return num_masters;
+}
+
+/*******************************************************************************
+ * This function validates parameters passed by the platform (in a debug build).
+ * It collects information about the maximum number of master interfaces that:
+ * a) the CCN IP can accommodate and
+ * b) can exist on each Request node.
+ * It compares this with the information provided by the platform to determine
+ * the validity of the latter.
+ ******************************************************************************/
+static void __init ccn_validate_plat_params(const ccn_desc_t *plat_desc)
+{
+	unsigned int master_id, num_rn_masters;
+	rn_info_t info = { {0} };
+
+	assert(plat_desc);
+	assert(plat_desc->periphbase);
+	assert(plat_desc->master_to_rn_id_map);
+	assert(plat_desc->num_masters);
+	assert(plat_desc->num_masters < CCN_MAX_RN_MASTERS);
+
+	/*
+	 * Find the number and properties of fully coherent, IO coherent and IO
+	 * coherent + DVM master interfaces
+	 */
+	num_rn_masters = ccn_get_rn_master_info(plat_desc->periphbase, &info);
+	assert(plat_desc->num_masters < num_rn_masters);
+
+	/*
+	 * Iterate through the Request nodes specified by the platform.
+	 * Decrement the count of the masters in the 'info' array for each
+	 * Request node encountered. If the count would drop below 0 then the
+	 * platform's view of this aspect of CCN configuration is incorrect.
+	 */
+	for (master_id = 0; master_id < plat_desc->num_masters; master_id++) {
+		unsigned int node_id;
+
+		node_id = plat_desc->master_to_rn_id_map[master_id];
+		assert(node_id < MAX_RN_NODES);
+		assert(info.node_desc[node_id]);
+		info.node_desc[node_id]--;
+	}
+}
+#endif /* ENABLE_ASSERTIONS */
+
+/*******************************************************************************
+ * This function validates parameters passed by the platform (in a debug build)
+ * and initialises its internal data structures. A lock is required to prevent
+ * simultaneous CCN operations at runtime (only BL31) to add and remove Request
+ * nodes from coherency.
+ ******************************************************************************/
+void __init ccn_init(const ccn_desc_t *plat_desc)
+{
+#if ENABLE_ASSERTIONS
+	ccn_validate_plat_params(plat_desc);
+#endif
+
+	ccn_plat_desc = plat_desc;
+}
+
+/*******************************************************************************
+ * This function converts a bit map of master interface IDs to a bit map of the
+ * Request node IDs that they reside on.
+ ******************************************************************************/
+static unsigned long long ccn_master_to_rn_id_map(unsigned long long master_map)
+{
+	unsigned long long rn_id_map = 0;
+	unsigned int node_id, iface_id;
+
+	assert(master_map);
+	assert(ccn_plat_desc);
+
+	FOR_EACH_PRESENT_MASTER_INTERFACE(iface_id, master_map) {
+		assert(iface_id < ccn_plat_desc->num_masters);
+
+		/* Convert the master ID into the node ID */
+		node_id = ccn_plat_desc->master_to_rn_id_map[iface_id];
+
+		/* Set the bit corresponding to this node ID */
+		rn_id_map |= (1ULL << node_id);
+	}
+
+	return rn_id_map;
+}
+
+/*******************************************************************************
+ * This function executes the necessary operations to add or remove Request node
+ * IDs specified in the 'rn_id_map' bitmap from the snoop/DVM domains specified
+ * in the 'hn_id_map'. The 'region_id' specifies the ID of the first HN-F/MN
+ * on which the operation should be performed. 'op_reg_offset' specifies the
+ * type of operation (add/remove). 'stat_reg_offset' specifies the register
+ * which should be polled to determine if the operation has completed or not.
+ ******************************************************************************/
+static void ccn_snoop_dvm_do_op(unsigned long long rn_id_map,
+				unsigned long long hn_id_map,
+				unsigned int region_id,
+				unsigned int op_reg_offset,
+				unsigned int stat_reg_offset)
+{
+	unsigned int start_region_id;
+
+	assert(ccn_plat_desc);
+	assert(ccn_plat_desc->periphbase);
+
+#if defined(IMAGE_BL31) || (!defined(__aarch64__) && defined(IMAGE_BL32))
+	bakery_lock_get(&ccn_lock);
+#endif
+	start_region_id = region_id;
+	FOR_EACH_PRESENT_REGION_ID(start_region_id, hn_id_map) {
+		ccn_reg_write(ccn_plat_desc->periphbase,
+			      start_region_id,
+			      op_reg_offset,
+			      rn_id_map);
+	}
+
+	start_region_id = region_id;
+
+	FOR_EACH_PRESENT_REGION_ID(start_region_id, hn_id_map) {
+		WAIT_FOR_DOMAIN_CTRL_OP_COMPLETION(start_region_id,
+						   stat_reg_offset,
+						   op_reg_offset,
+						   rn_id_map);
+	}
+
+#if defined(IMAGE_BL31) || (!defined(__aarch64__) && defined(IMAGE_BL32))
+	bakery_lock_release(&ccn_lock);
+#endif
+}
+
+/*******************************************************************************
+ * The following functions provide the boot and runtime API to the platform for
+ * adding and removing master interfaces from the snoop/DVM domains. A bitmap of
+ * master interfaces IDs is passed as a parameter. It is converted into a bitmap
+ * of Request node IDs using the mapping provided by the platform while
+ * initialising the driver.
+ * For example, consider a dual cluster system where the clusters have values 0
+ * & 1 in the affinity level 1 field of their respective MPIDRs. While
+ * initialising this driver, the platform provides the mapping between each
+ * cluster and the corresponding Request node. To add or remove a cluster from
+ * the snoop and dvm domain, the bit position corresponding to the cluster ID
+ * should be set in the 'master_iface_map' i.e. to remove both clusters the
+ * bitmap would equal 0x11.
+ ******************************************************************************/
+void ccn_enter_snoop_dvm_domain(unsigned long long master_iface_map)
+{
+	unsigned long long rn_id_map;
+
+	rn_id_map = ccn_master_to_rn_id_map(master_iface_map);
+	ccn_snoop_dvm_do_op(rn_id_map,
+			    CCN_GET_HN_NODEID_MAP(ccn_plat_desc->periphbase,
+						  MN_HNF_NODEID_OFFSET),
+			    HNF_REGION_ID_START,
+			    HNF_SDC_SET_OFFSET,
+			    HNF_SDC_STAT_OFFSET);
+
+	ccn_snoop_dvm_do_op(rn_id_map,
+			    CCN_GET_MN_NODEID_MAP(ccn_plat_desc->periphbase),
+			    MN_REGION_ID,
+			    MN_DDC_SET_OFFSET,
+			    MN_DDC_STAT_OFFSET);
+}
+
+void ccn_exit_snoop_dvm_domain(unsigned long long master_iface_map)
+{
+	unsigned long long rn_id_map;
+
+	rn_id_map = ccn_master_to_rn_id_map(master_iface_map);
+	ccn_snoop_dvm_do_op(rn_id_map,
+			    CCN_GET_HN_NODEID_MAP(ccn_plat_desc->periphbase,
+						  MN_HNF_NODEID_OFFSET),
+			    HNF_REGION_ID_START,
+			    HNF_SDC_CLR_OFFSET,
+			    HNF_SDC_STAT_OFFSET);
+
+	ccn_snoop_dvm_do_op(rn_id_map,
+			    CCN_GET_MN_NODEID_MAP(ccn_plat_desc->periphbase),
+			    MN_REGION_ID,
+			    MN_DDC_CLR_OFFSET,
+			    MN_DDC_STAT_OFFSET);
+}
+
+void ccn_enter_dvm_domain(unsigned long long master_iface_map)
+{
+	unsigned long long rn_id_map;
+
+	rn_id_map = ccn_master_to_rn_id_map(master_iface_map);
+	ccn_snoop_dvm_do_op(rn_id_map,
+			    CCN_GET_MN_NODEID_MAP(ccn_plat_desc->periphbase),
+			    MN_REGION_ID,
+			    MN_DDC_SET_OFFSET,
+			    MN_DDC_STAT_OFFSET);
+}
+
+void ccn_exit_dvm_domain(unsigned long long master_iface_map)
+{
+	unsigned long long rn_id_map;
+
+	rn_id_map = ccn_master_to_rn_id_map(master_iface_map);
+	ccn_snoop_dvm_do_op(rn_id_map,
+			    CCN_GET_MN_NODEID_MAP(ccn_plat_desc->periphbase),
+			    MN_REGION_ID,
+			    MN_DDC_CLR_OFFSET,
+			    MN_DDC_STAT_OFFSET);
+}
+
+/*******************************************************************************
+ * This function returns the run mode of all the L3 cache partitions in the
+ * system. The state is expected to be one of NO_L3, SF_ONLY, L3_HAM or
+ * L3_FAM. Instead of comparing the states reported by all HN-Fs, the state of
+ * the first present HN-F node is reported. Since the driver does not export an
+ * interface to program them separately, there is no reason to perform this
+ * check. An HN-F could report that the L3 cache is transitioning from one mode
+ * to another e.g. HNF_PM_NOL3_2_SFONLY. In this case, the function waits for
+ * the transition to complete and reports the final state.
+ ******************************************************************************/
+unsigned int ccn_get_l3_run_mode(void)
+{
+	unsigned long long hnf_pstate_stat;
+
+	assert(ccn_plat_desc);
+	assert(ccn_plat_desc->periphbase);
+
+	/*
+	 * Wait for a L3 cache partition to enter any run mode. The pstate
+	 * parameter is read from an HN-F P-state status register. A non-zero
+	 * value in bits[1:0] means that the cache is transitioning to a run
+	 * mode.
+	 */
+	do {
+		hnf_pstate_stat = ccn_reg_read(ccn_plat_desc->periphbase,
+					       HNF_REGION_ID_START,
+					       HNF_PSTATE_STAT_OFFSET);
+	} while (hnf_pstate_stat & 0x3);
+
+	return PSTATE_TO_RUN_MODE(hnf_pstate_stat);
+}
+
+/*******************************************************************************
+ * This function sets the run mode of all the L3 cache partitions in the
+ * system to one of NO_L3, SF_ONLY, L3_HAM or L3_FAM depending upon the state
+ * specified by the 'mode' argument.
+ ******************************************************************************/
+void ccn_set_l3_run_mode(unsigned int mode)
+{
+	unsigned long long mn_hnf_id_map, hnf_pstate_stat;
+	unsigned int region_id;
+
+	assert(ccn_plat_desc);
+	assert(ccn_plat_desc->periphbase);
+	assert(mode <= CCN_L3_RUN_MODE_FAM);
+
+	mn_hnf_id_map = ccn_reg_read(ccn_plat_desc->periphbase,
+				     MN_REGION_ID,
+				     MN_HNF_NODEID_OFFSET);
+	region_id = HNF_REGION_ID_START;
+
+	/* Program the desired run mode */
+	FOR_EACH_PRESENT_REGION_ID(region_id, mn_hnf_id_map) {
+		ccn_reg_write(ccn_plat_desc->periphbase,
+			      region_id,
+			      HNF_PSTATE_REQ_OFFSET,
+			      mode);
+	}
+
+	/* Wait for the caches to transition to the run mode */
+	region_id = HNF_REGION_ID_START;
+	FOR_EACH_PRESENT_REGION_ID(region_id, mn_hnf_id_map) {
+		/*
+		 * Wait for a L3 cache partition to enter a target run
+		 * mode. The pstate parameter is read from an HN-F P-state
+		 * status register.
+		 */
+		do {
+			hnf_pstate_stat = ccn_reg_read(ccn_plat_desc->periphbase,
+					       region_id,
+					       HNF_PSTATE_STAT_OFFSET);
+		} while (((hnf_pstate_stat & HNF_PSTATE_MASK) >> 2) != mode);
+	}
+}
+
+/*******************************************************************************
+ * This function configures system address map and provides option to enable the
+ * 3SN striping mode of Slave node operation. The Slave node IDs and the Top
+ * Address bit1 and bit0 are provided as parameters to this function. This
+ * configuration is needed only if network contains a single SN-F or 3 SN-F and
+ * must be completed before the first request by the system to normal memory.
+ ******************************************************************************/
+void ccn_program_sys_addrmap(unsigned int sn0_id,
+		 unsigned int sn1_id,
+		 unsigned int sn2_id,
+		 unsigned int top_addr_bit0,
+		 unsigned int top_addr_bit1,
+		 unsigned char three_sn_en)
+{
+	unsigned long long mn_hnf_id_map, hnf_sam_ctrl_value;
+	unsigned int region_id;
+
+	assert(ccn_plat_desc);
+	assert(ccn_plat_desc->periphbase);
+
+	mn_hnf_id_map = ccn_reg_read(ccn_plat_desc->periphbase,
+				     MN_REGION_ID,
+				     MN_HNF_NODEID_OFFSET);
+	region_id = HNF_REGION_ID_START;
+	hnf_sam_ctrl_value = MAKE_HNF_SAM_CTRL_VALUE(sn0_id,
+						     sn1_id,
+						     sn2_id,
+						     top_addr_bit0,
+						     top_addr_bit1,
+						     three_sn_en);
+
+	FOR_EACH_PRESENT_REGION_ID(region_id, mn_hnf_id_map) {
+
+		/* Program the SAM control register */
+		ccn_reg_write(ccn_plat_desc->periphbase,
+			      region_id,
+			      HNF_SAM_CTRL_OFFSET,
+			      hnf_sam_ctrl_value);
+	}
+
+}
+
+/*******************************************************************************
+ * This function returns the part0 id from the peripheralID 0 register
+ * in CCN. This id can be used to distinguish the CCN variant present in the
+ * system.
+ ******************************************************************************/
+int ccn_get_part0_id(uintptr_t periphbase)
+{
+	assert(periphbase);
+	return (int)(mmio_read_64(periphbase
+			+ MN_PERIPH_ID_0_1_OFFSET) & 0xFF);
+}
+
+/*******************************************************************************
+ * This function returns the region id corresponding to a node_id of node_type.
+ ******************************************************************************/
+static unsigned int get_region_id_for_node(node_types_t node_type,
+						unsigned int node_id)
+{
+	unsigned int mn_reg_off, region_id;
+	unsigned long long node_bitmap;
+	unsigned int loc_node_id, node_pos_in_map = 0;
+
+	assert(node_type < NUM_NODE_TYPES);
+	assert(node_id < MAX_RN_NODES);
+
+	switch (node_type) {
+	case NODE_TYPE_RNI:
+		region_id = RNI_REGION_ID_START;
+		break;
+	case NODE_TYPE_HNF:
+		region_id = HNF_REGION_ID_START;
+		break;
+	case NODE_TYPE_HNI:
+		region_id = HNI_REGION_ID_START;
+		break;
+	case NODE_TYPE_SN:
+		region_id = SBSX_REGION_ID_START;
+		break;
+	default:
+		ERROR("Un-supported Node Type = %d.\n", node_type);
+		assert(false);
+		return REGION_ID_LIMIT;
+	}
+	/*
+	 * RN-I, HN-F, HN-I, SN node registers in the MN region
+	 * occupy contiguous 16 byte apart offsets.
+	 *
+	 * RN-F and RN-D node are not supported as
+	 * none of them exposes any memory map to
+	 * configure any of their offset registers.
+	 */
+
+	mn_reg_off = MN_RNF_NODEID_OFFSET + (node_type << 4);
+	node_bitmap = ccn_reg_read(ccn_plat_desc->periphbase,
+					MN_REGION_ID, mn_reg_off);
+
+	assert((node_bitmap & (1ULL << (node_id))) != 0U);
+
+
+	FOR_EACH_PRESENT_NODE_ID(loc_node_id, node_bitmap) {
+		INFO("Index = %u with loc_nod=%u and input nod=%u\n",
+					node_pos_in_map, loc_node_id, node_id);
+		if (loc_node_id == node_id)
+			break;
+		node_pos_in_map++;
+	}
+
+	if (node_pos_in_map == CCN_MAX_RN_MASTERS) {
+		ERROR("Node Id = %d, is not found.\n", node_id);
+		assert(false);
+		return REGION_ID_LIMIT;
+	}
+
+	/*
+	 * According to section 3.1.1 in CCN specification, region offset for
+	 * the RN-I components is calculated as (128 + NodeID of RN-I).
+	 */
+	if (node_type == NODE_TYPE_RNI)
+		region_id += node_id;
+	else
+		region_id += node_pos_in_map;
+
+	return region_id;
+}
+
+/*******************************************************************************
+ * This function sets the value 'val' to the register at register_offset from
+ * the base address pointed to by the region_id.
+ * where, region id is mapped to a node_id of node_type.
+ ******************************************************************************/
+void ccn_write_node_reg(node_types_t node_type, unsigned int node_id,
+			unsigned int reg_offset, unsigned long long val)
+{
+	unsigned int region_id = get_region_id_for_node(node_type, node_id);
+
+	if (reg_offset > REGION_ID_OFFSET) {
+		ERROR("Invalid Register offset 0x%x is provided.\n",
+								reg_offset);
+		assert(false);
+		return;
+	}
+
+	/* Setting the value of Auxiliary Control Register of the Node */
+	ccn_reg_write(ccn_plat_desc->periphbase, region_id, reg_offset, val);
+	VERBOSE("Value is successfully written at address 0x%lx.\n",
+			(ccn_plat_desc->periphbase
+			+ region_id_to_base(region_id))
+			+ reg_offset);
+}
+
+/*******************************************************************************
+ * This function read the value 'val' stored in the register at register_offset
+ * from the base address pointed to by the region_id.
+ * where, region id is mapped to a node_id of node_type.
+ ******************************************************************************/
+unsigned long long ccn_read_node_reg(node_types_t node_type,
+					unsigned int node_id,
+					unsigned int reg_offset)
+{
+	unsigned long long val;
+	unsigned int region_id = get_region_id_for_node(node_type, node_id);
+
+	if (reg_offset > REGION_ID_OFFSET) {
+		ERROR("Invalid Register offset 0x%x is provided.\n",
+								reg_offset);
+		assert(false);
+		return ULL(0);
+	}
+
+	/* Setting the value of Auxiliary Control Register of the Node */
+	val = ccn_reg_read(ccn_plat_desc->periphbase, region_id, reg_offset);
+	VERBOSE("Value is successfully read from address 0x%lx.\n",
+			(ccn_plat_desc->periphbase
+			+ region_id_to_base(region_id))
+			+ reg_offset);
+
+	return val;
+}