path: root/drivers/of/fdt.c

/*
 * Functions for working with the Flattened Device Tree data format
 *
 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
 * benh@kernel.crashing.org
 *
 * 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/kernel.h>
#include <linux/initrd.h>
#include <linux/memblock.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>

#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#endif /* CONFIG_PPC */

#include <asm/page.h>

char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
{
	return ((char *)blob) +
		be32_to_cpu(blob->off_dt_strings) + offset;
}

/**
 * of_fdt_get_property - Given a node in the given flat blob, return
 * the property ptr
 */
void *of_fdt_get_property(struct boot_param_header *blob,
		       unsigned long node, const char *name,
		       unsigned long *size)
{
	unsigned long p = node;

	do {
		u32 tag = be32_to_cpup((__be32 *)p);
		u32 sz, noff;
		const char *nstr;

		p += 4;
		if (tag == OF_DT_NOP)
			continue;
		if (tag != OF_DT_PROP)
			return NULL;

		sz = be32_to_cpup((__be32 *)p);
		noff = be32_to_cpup((__be32 *)(p + 4));
		p += 8;
		if (be32_to_cpu(blob->version) < 0x10)
			p = ALIGN(p, sz >= 8 ? 8 : 4);

		nstr = of_fdt_get_string(blob, noff);
		if (nstr == NULL) {
			pr_warning("Can't find property index name !\n");
			return NULL;
		}
		if (strcmp(name, nstr) == 0) {
			if (size)
				*size = sz;
			return (void *)p;
		}
		p += sz;
		p = ALIGN(p, 4);
	} while (1);
}

/**
 * of_fdt_is_compatible - Return true if given node from the given blob has
 * compat in its compatible list
 * @blob: A device tree blob
 * @node: node to test
 * @compat: compatible string to compare with compatible list.
 *
 * On match, returns a non-zero value with smaller values returned for more
 * specific compatible values.
 */
int of_fdt_is_compatible(struct boot_param_header *blob,
		      unsigned long node, const char *compat)
{
	const char *cp;
	unsigned long cplen, l, score = 0;

	cp = of_fdt_get_property(blob, node, "compatible", &cplen);
	if (cp == NULL)
		return 0;
	while (cplen > 0) {
		score++;
		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
			return score;
		l = strlen(cp) + 1;
		cp += l;
		cplen -= l;
	}

	return 0;
}

/**
 * of_fdt_match - Return true if node matches a list of compatible values
 */
int of_fdt_match(struct boot_param_header *blob, unsigned long node,
                 const char *const *compat)
{
	unsigned int tmp, score = 0;

	if (!compat)
		return 0;

	while (*compat) {
		tmp = of_fdt_is_compatible(blob, node, *compat);
		if (tmp && (score == 0 || (tmp < score)))
			score = tmp;
		compat++;
	}

	return score;
}

static void *unflatten_dt_alloc(void **mem, unsigned long size,
				       unsigned long align)
{
	void *res;

	*mem = PTR_ALIGN(*mem, align);
	res = *mem;
	*mem += size;

	return res;
}

/**
 * unflatten_dt_node - Alloc and populate a device_node from the flat tree
 * @blob: The parent device tree blob
 * @mem: Memory chunk to use for allocating device nodes and properties
 * @p: pointer to node in flat tree
 * @dad: Parent struct device_node
 * @allnextpp: pointer to ->allnext from last allocated device_node
 * @fpsize: Size of the node path up at the current depth.
 */
static void * unflatten_dt_node(struct boot_param_header *blob,
				void *mem,
				void **p,
				struct device_node *dad,
				struct device_node ***allnextpp,
				unsigned long fpsize)
{
	struct device_node *np;
	struct property *pp, **prev_pp = NULL;
	char *pathp;
	u32 tag;
	unsigned int l, allocl;
	int has_name = 0;
	int new_format = 0;

	tag = be32_to_cpup(*p);
	if (tag != OF_DT_BEGIN_NODE) {
		pr_err("Weird tag at start of node: %x\n", tag