xref: /openbmc/linux/arch/nios2/kernel/prom.c (revision be709d48)
1 /*
2  * Device tree support
3  *
4  * Copyright (C) 2013, 2015 Altera Corporation
5  * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
6  *
7  * Based on MIPS support for CONFIG_OF device tree support
8  *
9  * Copyright (C) 2010 Cisco Systems Inc. <dediao@cisco.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
23  *
24  */
25 
26 #include <linux/init.h>
27 #include <linux/types.h>
28 #include <linux/memblock.h>
29 #include <linux/of.h>
30 #include <linux/of_fdt.h>
31 #include <linux/io.h>
32 
33 #include <asm/sections.h>
34 
35 void __init early_init_devtree(void *params)
36 {
37 	__be32 *dtb = (u32 *)__dtb_start;
38 #if defined(CONFIG_NIOS2_DTB_AT_PHYS_ADDR)
39 	if (be32_to_cpup((__be32 *)CONFIG_NIOS2_DTB_PHYS_ADDR) ==
40 		 OF_DT_HEADER) {
41 		params = (void *)CONFIG_NIOS2_DTB_PHYS_ADDR;
42 		early_init_dt_scan(params);
43 		return;
44 	}
45 #endif
46 	if (be32_to_cpu((__be32) *dtb) == OF_DT_HEADER)
47 		params = (void *)__dtb_start;
48 
49 	early_init_dt_scan(params);
50 }
51