arch/nios2/kernel/prom.c

   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/bootmem.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 }