linux/arch/arc/kernel/devtree.c
Vineet Gupta 999159a538 ARC: [DeviceTree] Basic support
This is minimal infrastructure needed for devicetree work.
It uses an a sample "skeleton" devicetree - embedded in kernel image -
to print the board, manufacturer by parsing the top-level "compatible"
string.

As of now we don't need any additional "board" specific "machine_desc".

TODO: support interpreting the command line as boot-loader passed dtb

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
2013-02-15 23:15:55 +05:30

65 lines
1.7 KiB
C

/*
* Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
*
* Based on reduced version of METAG
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/reboot.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <asm/prom.h>
/* called from unflatten_device_tree() to bootstrap devicetree itself */
void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
{
return __va(memblock_alloc(size, align));
}
/**
* setup_machine_fdt - Machine setup when an dtb was passed to the kernel
* @dt: virtual address pointer to dt blob
*
* If a dtb was passed to the kernel, then use it to choose the correct
* machine_desc and to setup the system.
*/
int __init setup_machine_fdt(void *dt)
{
struct boot_param_header *devtree = dt;
unsigned long dt_root;
char *model, *compat;
char manufacturer[16];
/* check device tree validity */
if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
return 1;
/* Search the mdescs for the 'best' compatible value match */
initial_boot_params = devtree;
dt_root = of_get_flat_dt_root();
/* compat = "<manufacturer>,<model>" */
compat = of_get_flat_dt_prop(dt_root, "compatible", NULL);
if (!compat)
compat = "<unknown>";
model = strchr(compat, ',');
if (model)
model++;
strlcpy(manufacturer, compat, model ? model - compat : strlen(compat));
pr_info("Board \"%s\" from %s (Manufacturer)\n", model, manufacturer);
/* Retrieve various information from the /chosen node */
of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
return 0;
}