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				/*-
				* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
				*
				* Copyright (c) 2021 Beckhoff Automation GmbH & Co. KG
				* Author: Corvin Köhne <c.koehne@beckhoff.com>
				*/

				#include <sys/cdefs.h>

				#include <sys/types.h>
				#include <sys/param.h>
				#include <sys/systm.h>
				#include <sys/malloc.h>

				#include <contrib/dev/acpica/include/acpi.h>
				#include <contrib/dev/acpica/include/acpixf.h>

				#include "acpi.h"

				int
				vmm_acpi_get_crs(const char const device_path, void const buffer,
				size_t *const buffer_length)
				{
				if (device_path == NULL \|\| buffer_length == NULL) {
				return (EINVAL);
				}

				/* get device handle */
				ACPI_HANDLE acpi_device;
				ACPI_STRING const path = strdup(device_path, M_TEMP);
				ACPI_STATUS status = AcpiGetHandle(NULL, path, &acpi_device);
				if (!ACPI_SUCCESS(status)) {
				printf("%s: failed to get handle for ACPI device \"%s\" (%x)\n",
				__func__, device_path, status);
				return (ENOENT);
				}

				/* get current resources */
				ACPI_BUFFER resources = { ACPI_ALLOCATE_BUFFER };
				status = AcpiGetCurrentResources(acpi_device, &resources);
				if (!ACPI_SUCCESS(status)) {
				printf(
				"%s: failed to get current resources of ACPI device \"%s\" (%x)\n",
				__func__, device_path, status);
				return (ENODEV);
				}

				/* copy data to user space buffer */
				int error = 0;
				if (buffer == NULL) {
				*buffer_length = resources.Length;
				} else {
				size_t bytes_to_write = MIN(*buffer_length, resources.Length);
				error = copyout(resources.Pointer, buffer, bytes_to_write);
				}

				AcpiOsFree(resources.Pointer);

				return (error);
				}