xref: /linux/arch/nios2/kernel/prom.c (revision 5c1672705a1a2389f5ad78e0fea6f08ed32d6f18)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Device tree support
4  *
5  * Copyright (C) 2013, 2015 Altera Corporation
6  * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
7  *
8  * Based on MIPS support for CONFIG_OF device tree support
9  *
10  * Copyright (C) 2010 Cisco Systems Inc. <dediao@cisco.com>
11  */
12 
13 #include <linux/init.h>
14 #include <linux/types.h>
15 #include <linux/memblock.h>
16 #include <linux/of.h>
17 #include <linux/of_fdt.h>
18 #include <linux/io.h>
19 
20 #include <asm/sections.h>
21 
22 void __init early_init_devtree(void *params)
23 {
24 	__be32 __maybe_unused *dtb = (u32 *)__dtb_start;
25 
26 #if defined(CONFIG_NIOS2_DTB_AT_PHYS_ADDR)
27 	if (be32_to_cpup((__be32 *)CONFIG_NIOS2_DTB_PHYS_ADDR) ==
28 		 OF_DT_HEADER) {
29 		params = (void *)CONFIG_NIOS2_DTB_PHYS_ADDR;
30 		early_init_dt_scan(params);
31 		return;
32 	}
33 #endif
34 
35 #ifdef CONFIG_NIOS2_DTB_SOURCE_BOOL
36 	if (be32_to_cpu((__be32) *dtb) == OF_DT_HEADER)
37 		params = (void *)__dtb_start;
38 #endif
39 
40 	early_init_dt_scan(params);
41 }
42