feat(intel): add FDT support for Altera products

Support FDT for Agilex5 platform
1. Created wrapper file socfpga_dt.c
2. Added in Agilex5 dts file
3. Implemented fdt_check_header
4. Implemented gic configuration
5. Implemented dram configuration

Remove init of FDT as Agilex5 has no plan to roll
out FDT at the moment.

Change-Id: If3990ed9524c6da5b3cb8966b63bc4a95d01fcda
Signed-off-by: Jit Loon Lim <jit.loon.lim@altera.com>
diff --git a/plat/intel/soc/common/socfpga_dt.c b/plat/intel/soc/common/socfpga_dt.c
new file mode 100644
index 0000000..0333b9b
--- /dev/null
+++ b/plat/intel/soc/common/socfpga_dt.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2024-2025, Altera Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <errno.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <common/fdt_wrappers.h>
+#include <common/tbbr/tbbr_img_def.h>
+#include <drivers/arm/gic_common.h>
+#include <drivers/arm/gicv3.h>
+#include <drivers/delay_timer.h>
+#include <lib/mmio.h>
+#include <lib/utils.h>
+#include <libfdt.h>
+#include <platform_def.h>
+#include <tools_share/firmware_image_package.h>
+
+#include "socfpga_dt.h"
+
+static const void *fdt;
+/*******************************************************************************
+ * This function checks device tree file with its header.
+ * Returns 0 on success and a negative FDT error code on failure.
+ ******************************************************************************/
+int socfpga_dt_open_and_check(uintptr_t dt_addr, char *compatible_str)
+{
+	int ret = 0;
+	int node = 1;
+
+	ret = fdt_check_header((void *)dt_addr);
+
+	if (ret != 0) {
+		ERROR("SOCFPGA: FDT Header invalid\n");
+		return ret;
+	}
+
+	fdt = (const void *)dt_addr;
+
+	/* As libfdt use void *, we can't avoid this cast */
+	const void *dtb = (void *)dt_addr;
+
+	/* Assert the node offset point to compatible property */
+	node = fdt_node_offset_by_compatible(dtb, -1, compatible_str);
+	if (node < 0) {
+		ERROR("SOCFPGA: Can't find `%s` compatible in dtb\n",
+						compatible_str);
+		return node;
+	}
+
+	NOTICE("SOCFPGA: Successfully open and check FDT\n");
+
+	return ret;
+}
+
+int socfpga_dt_populate_gicv3_config(uintptr_t dt_addr, gicv3_driver_data_t *plat_driver_data)
+{
+	int err;
+	int node;
+	uintptr_t addr;
+
+	/* Necessary to work with libfdt APIs */
+	const void *hw_config_dtb = (const void *)dt_addr;
+	/*
+	 * Find the offset of the node containing "arm,gic-v3" compatible property.
+	 * Populating fconf strucutures dynamically is not supported for legacy
+	 * systems which use GICv2 IP. Simply skip extracting GIC properties.
+	 */
+	node = fdt_node_offset_by_compatible(hw_config_dtb, -1, "arm,gic-v3");
+	if (node < 0) {
+		ERROR("SOCFPGA: Unable to locate node with arm,gic-v3 compatible property\n");
+		return 0;
+	}
+	/* The GICv3 DT binding holds at least two address/size pairs,
+	 * the first describing the distributor, the second the redistributors.
+	 * See: bindings/interrupt-controller/arm,gic-v3.yaml
+	 */
+	err = fdt_get_reg_props_by_index(hw_config_dtb, node, 0, &addr, NULL);
+	if (err < 0) {
+		ERROR("SOCFPGA: Failed to read GICD reg property of GIC node\n");
+	} else {
+		plat_driver_data->gicd_base = addr;
+	}
+
+	err = fdt_get_reg_props_by_index(hw_config_dtb, node, 1, &addr, NULL);
+	if (err < 0) {
+		ERROR("SOCFPGA: Failed to read GICR reg property of GIC node\n");
+	} else {
+		plat_driver_data->gicr_base = addr;
+	}
+	return err;
+}
+
+int socfpga_dt_populate_dram_layout(uintptr_t dt_addr)
+{
+	int node;
+	uintptr_t addr;
+	size_t size;
+
+	/* Necessary to work with libfdt APIs */
+	const void *hw_config_dtb = (const void *)dt_addr;
+
+	/* Find 'memory' node */
+	node = fdt_node_offset_by_prop_value(hw_config_dtb, -1, "device_type",
+					     "memory", sizeof("memory"));
+	if (node < 0) {
+		NOTICE("SOCFPGA: Unable to locate 'memory' node\n");
+		return node;
+	}
+
+	int err = fdt_get_reg_props_by_index(
+			hw_config_dtb, node, 0,
+			&addr, (size_t *)&size);
+
+	NOTICE("SOCFPGA: Mem base 0x%lx, Mem size 0x%lx\n", addr, size);
+	if (err < 0) {
+		ERROR("SOCFPGA: Failed to read 'reg' property of 'memory' node\n");
+		return err;
+	}
+
+	return 0;
+}