[efi] Register a device tree if provided by the platform firmware
[ipxe.git] / src / interface / efi / efi_fdt.c
1 /*
2 * Copyright (C) 2019 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <string.h>
27 #include <ipxe/fdt.h>
28 #include <ipxe/efi/efi.h>
29 #include <ipxe/init.h>
30
31 /** @file
32 *
33 * EFI Flattened Device Tree
34 *
35 */
36
37 #define DEVICE_TREE_TABLE_GUID \
38 { 0xb1b621d5, 0xf19c, 0x41a5, \
39 { 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0 } }
40
41 /** EFI Flattened Device Tree configuration table */
42 static struct fdt_header *efi_fdt;
43 EFI_USE_TABLE ( DEVICE_TREE_TABLE, &efi_fdt, 0 );
44
45 /**
46 * Initialise EFI Flattened Device Tree
47 *
48 */
49 static void efi_fdt_init ( void ) {
50 int rc;
51
52 /* Do nothing if no configuration table is present */
53 if ( ! efi_fdt ) {
54 DBGC ( &efi_fdt, "EFIFDT has no configuration table\n" );
55 return;
56 }
57 DBGC ( &efi_fdt, "EFIFDT configuration table at %p\n", efi_fdt );
58
59 /* Register device tree */
60 if ( ( rc = register_fdt ( efi_fdt ) ) != 0 ) {
61 DBGC ( &efi_fdt, "EFIFDT could not register: %s\n",
62 strerror ( rc ) );
63 return;
64 }
65 }
66
67 /** EFI Flattened Device Tree initialisation function */
68 struct init_fn efi_fdt_init_fn __init_fn ( INIT_EARLY ) = {
69 .initialise = efi_fdt_init,
70 };