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/*
* (C) Copyright David Gibson <dwg@au1.ibm.com>, IBM Corporation. 2005.
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*/
#include <stdint.h>
#include <string.h>
#include "flat_dt.h"
#define ALIGN(x, a) (((x) + ((a) - 1)) & ~((a) - 1))
#define PALIGN(p, a) ((void *)(ALIGN((unsigned long)(p), (a))))
#define GET_CELL(p) (p += 4, *((uint32_t *)(p-4)))
static char *skip_name(char *p)
{
while (*p != '\0')
p++;
return PALIGN(p, sizeof(uint32_t));
}
static char *skip_prop(void *blob, char *p)
{
struct boot_param_header *bph = blob;
uint32_t len, nameoff;
len = GET_CELL(p);
nameoff = GET_CELL(p);
if ((bph->version < 0x10) && (len >= sizeof(uint64_t)))
p = PALIGN(p, sizeof(uint64_t));
return PALIGN(p + len, sizeof(uint32_t));
}
static char *get_unit(char *dtpath)
{
char *p;
if (dtpath[0] != '/')
return dtpath;
p = dtpath + strlen(dtpath);
while (*p != '/')
p--;
return p+1;
}
static int first_seg_len(char *dtpath)
{
int len = 0;
while ((dtpath[len] != '/') && (dtpath[len] != '\0'))
len++;
return len;
}
char *flat_dt_get_string(void *blob, uint32_t offset)
{
struct boot_param_header *bph = blob;
return (char *)blob + bph->off_dt_strings + offset;
}
void *flat_dt_get_subnode(void *blob, void *node, char *uname, int unamelen)
{
struct boot_param_header *bph = blob;
char *p = node;
uint32_t tag;
int depth = 0;
char *nuname;
if (! unamelen)
unamelen = strlen(uname);
do {
tag = GET_CELL(p);
switch (tag) {
case OF_DT_PROP:
p = skip_prop(blob, p);
break;
case OF_DT_BEGIN_NODE:
if (depth == 0) {
nuname = p;
if (bph->version < 0x10)
nuname = get_unit(nuname);
p = skip_name(p);
if (strncmp(nuname, uname, unamelen) == 0)
return p;
}
depth++;
break;
case OF_DT_END_NODE:
depth--;
break;
case OF_DT_END:
/* looks like a malformed tree */
return NULL;
break;
default:
/* FIXME: throw some sort of error */
return NULL;
}
} while (depth >= 0);
return NULL;
}
void *flat_dt_get_node(void *blob, char *path)
{
struct boot_param_header *bph = blob;
char *node;
int seglen;
node = blob + bph->off_dt_struct;
node += sizeof(uint32_t); /* skip initial OF_DT_BEGIN_NODE */
node = skip_name(node); /* skip root node name */
while (node && (*path)) {
if (path[0] == '/')
path++;
seglen = first_seg_len(path);
node = flat_dt_get_subnode(blob, node, path, seglen);
path += seglen;
}
return node;
}
void flat_dt_traverse(void *blob,
int (*fn)(void *blob, void *node, void *priv),
void *private)
{
struct boot_param_header *bph = blob;
char *p;
uint32_t tag;
int depth = 0;
char *uname;
p = (char *)blob + bph->off_dt_struct;
tag = GET_CELL(p);
while (tag != OF_DT_END) {
switch (tag) {
case OF_DT_BEGIN_NODE:
uname = p;
if (bph->version < 0x10)
uname = get_unit(uname);
p = skip_name(p);
(*fn)(blob, p, private);
depth++;
break;
case OF_DT_END_NODE:
depth--;
break;
case OF_DT_PROP:
p = skip_prop(blob, p);
break;
default:
/* FIXME: badly formed tree */
return;
}
}
}
void *flat_dt_get_prop(void *blob, void *node, char *name, uint32_t *len)
{
struct boot_param_header *bph = blob;
char *p = node;
do {
uint32_t tag = GET_CELL(p);
uint32_t sz, noff;
const char *nstr;
if (tag != OF_DT_PROP)
return NULL;
sz = GET_CELL(p);
noff = GET_CELL(p);
/* Old versions have variable alignment of the
* property value */
if ((bph->version < 0x10) && (sz >= 8))
p = PALIGN(p, 8);
nstr = flat_dt_get_string(blob, noff);
if (strcmp(name, nstr) == 0) {
if (len)
*len = sz;
return (void *)p;
}
p = PALIGN(p + sz, sizeof(uint32_t));
} while(1);
}