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/*
* 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/of.h>
#include <linux/of_fdt.h>
struct boot_param_header *initial_boot_params;
char *find_flat_dt_string(u32 offset)
{
return ((char *)initial_boot_params) +
initial_boot_params->off_dt_strings + offset;
}
/**
* of_scan_flat_dt - scan flattened tree blob and call callback on each.
* @it: callback function
* @data: context data pointer
*
* This function is used to scan the flattened device-tree, it is
* used to extract the memory information at boot before we can
* unflatten the tree
*/
int __init of_scan_flat_dt(int (*it)(unsigned long node,
const char *uname, int depth,
void *data),
void *data)
{
unsigned long p = ((unsigned long)initial_boot_params) +
initial_boot_params->off_dt_struct;
int rc = 0;
int depth = -1;
do {
u32 tag = *((u32 *)p);
char *pathp;
p += 4;
if (tag == OF_DT_END_NODE) {
depth--;
continue;
}
if (tag == OF_DT_NOP)
continue;
if (tag == OF_DT_END)
break;
if (tag == OF_DT_PROP) {
u32 sz = *((u32 *)p);
p += 8;
if (initial_boot_params->version < 0x10)
p = _ALIGN(p, sz >= 8 ? 8 : 4);
p += sz;
p = _ALIGN(p, 4);
continue;
}
if (tag != OF_DT_BEGIN_NODE) {
pr_err("Invalid tag %x in flat device tree!\n", tag);
return -EINVAL;
}
depth++;
pathp = (char *)p;
p = _ALIGN(p + strlen(pathp) + 1, 4);
if ((*pathp) == '/') {
char *lp, *np;
for (lp = NULL, np = pathp; *np; np++)
if ((*np) == '/')
lp = np+1;
if (lp != NULL)
pathp = lp;
}
rc = it(p, pathp, depth, data);
if (rc != 0)
break;
} while (1);
return rc;
}
/**
* of_get_flat_dt_root - find the root node in the flat blob
*/
unsigned long __init of_get_flat_dt_root(void)
{
unsigned long p = ((unsigned long)initial_boot_params) +
initial_boot_params->off_dt_struct;
while (*((u32 *)p) == OF_DT_NOP)
p += 4;
BUG_ON(*((u32 *)p) != OF_DT_BEGIN_NODE);
p += 4;
return _ALIGN(p + strlen((char *)p) + 1, 4);
}
/**
* of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
*
* This function can be used within scan_flattened_dt callback to get
* access to properties
*/
void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
unsigned long *size)
{
unsigned long p = node;
do {
u32 tag = *((u32 *)p);
u32 sz, noff;
const char *nstr;
p += 4;
if (tag == OF_DT_NOP)
continue;
if (tag != OF_DT_PROP)
return NULL;
sz = *((u32 *)p);
noff = *((u32 *)(p + 4));
p += 8;
if (initial_boot_params->version < 0x10)
p = _ALIGN(p, sz >= 8 ? 8 : 4);
nstr = find_flat_dt_string(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);
}
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