1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  EFI application ACPI tables support
4  *
5  *  Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
6  */
7 
8 #include <common.h>
9 #include <efi_loader.h>
10 #include <log.h>
11 #include <acpi/acpi_table.h>
12 
13 static const efi_guid_t acpi_guid = EFI_ACPI_TABLE_GUID;
14 
15 /*
16  * Install the ACPI table as a configuration table.
17  *
18  * @return	status code
19  */
efi_acpi_register(void)20 efi_status_t efi_acpi_register(void)
21 {
22 	/* Map within the low 32 bits, to allow for 32bit ACPI tables */
23 	u64 acpi = U32_MAX;
24 	efi_status_t ret;
25 
26 	/* Reserve 64kiB page for ACPI */
27 	ret = efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
28 				 EFI_ACPI_RECLAIM_MEMORY, 16, &acpi);
29 	if (ret != EFI_SUCCESS)
30 		return ret;
31 
32 	/*
33 	 * Generate ACPI tables - we know that efi_allocate_pages() returns
34 	 * a 4k-aligned address, so it is safe to assume that
35 	 * write_acpi_tables() will write the table at that address.
36 	 */
37 	write_acpi_tables(acpi);
38 
39 	/* And expose them to our EFI payload */
40 	return efi_install_configuration_table(&acpi_guid,
41 					       (void *)(uintptr_t)acpi);
42 }
43