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/*
* Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/* Helper functions to offer easier navigation of Device Tree Blob */
#include <assert.h>
#include <string.h>
#include <libfdt.h>
#include <common/debug.h>
#include <common/fdt_wrappers.h>
/*
* Read cells from a given property of the given node. Any number of 32-bit
* cells of the property can be read. Returns 0 on success, or a negative
* FDT error value otherwise.
*/
int fdt_read_uint32_array(const void *dtb, int node, const char *prop_name,
unsigned int cells, uint32_t *value)
{
const fdt32_t *prop;
int value_len;
assert(dtb != NULL);
assert(prop_name != NULL);
assert(value != NULL);
assert(node >= 0);
/* Access property and obtain its length (in bytes) */
prop = fdt_getprop(dtb, node, prop_name, &value_len);
if (prop == NULL) {
WARN("Couldn't find property %s in dtb\n", prop_name);
return -FDT_ERR_NOTFOUND;
}
/* Verify that property length can fill the entire array. */
if (NCELLS((unsigned int)value_len) < cells) {
WARN("Property length mismatch\n");
return -FDT_ERR_BADVALUE;
}
for (unsigned int i = 0U; i < cells; i++) {
value[i] = fdt32_to_cpu(prop[i]);
}
return 0;
}
int fdt_read_uint32(const void *dtb, int node, const char *prop_name,
uint32_t *value)
{
return fdt_read_uint32_array(dtb, node, prop_name, 1, value);
}
uint32_t fdt_read_uint32_default(const void *dtb, int node,
const char *prop_name, uint32_t dflt_value)
{
uint32_t ret = dflt_value;
int err = fdt_read_uint32(dtb, node, prop_name, &ret);
if (err < 0) {
return dflt_value;
}
return ret;
}
int fdt_read_uint64(const void *dtb, int node, const char *prop_name,
uint64_t *value)
{
uint32_t array[2] = {0, 0};
int ret;
ret = fdt_read_uint32_array(dtb, node, prop_name, 2, array);
if (ret < 0) {
return ret;
}
*value = ((uint64_t)array[0] << 32) | array[1];
return 0;
}
/*
* Read bytes from a given property of the given node. Any number of
* bytes of the property can be read. The fdt pointer is updated.
* Returns 0 on success, and -1 on error.
*/
int fdtw_read_bytes(const void *dtb, int node, const char *prop,
unsigned int length, void *value)
{
const void *ptr;
int value_len;
assert(dtb != NULL);
assert(prop != NULL);
assert(value != NULL);
assert(node >= 0);
/* Access property and obtain its length (in bytes) */
ptr = fdt_getprop_namelen(dtb, node, prop, (int)strlen(prop),
&value_len);
if (ptr == NULL) {
WARN("Couldn't find property %s in dtb\n", prop);
return -1;
}
/* Verify that property length is not less than number of bytes */
if ((unsigned int)value_len < length) {
WARN("Property length mismatch\n");
return -1;
}
(void)memcpy(value, ptr, length);
return 0;
}
/*
* Read string from a given property of the given node. Up to 'size - 1'
* characters are read, and a NUL terminator is added. Returns 0 on success,
* and -1 upon error.
*/
int fdtw_read_string(const void *dtb, int node, const char *prop,
char *str, size_t size)
{
const char *ptr;
size_t len;
assert(dtb != NULL);
assert(node >= 0);
assert(prop != NULL);
assert(str != NULL);
assert(size > 0U);
ptr = fdt_getprop_namelen(dtb, node, prop, (int)strlen(prop), NULL);
if (ptr == NULL) {
WARN("Couldn't find property %s in dtb\n", prop);
return -1;
}
len = strlcpy(str, ptr, size);
if (len >= size) {
WARN("String of property %s in dtb has been truncated\n", prop);
return -1;
}
return 0;
}
/*
* Write cells in place to a given property of the given node. At most 2 cells
* of the property are written. Returns 0 on success, and -1 upon error.
*/
int fdtw_write_inplace_cells(void *dtb, int node, const char *prop,
unsigned int cells, void *value)
{
int err, len;
assert(dtb != NULL);
assert(prop != NULL);
assert(value != NULL);
assert(node >= 0);
/* We expect either 1 or 2 cell property */
assert(cells <= 2U);
if (cells == 2U)
*(uint64_t *)value = cpu_to_fdt64(*(uint64_t *)value);
else
*(uint32_t *)value = cpu_to_fdt32(*(uint32_t *)value);
len = (int)cells * 4;
/* Set property value in place */
err = fdt_setprop_inplace(dtb, node, prop, value, len);
if (err != 0) {
WARN("Modify property %s failed with error %d\n", prop, err);
return -1;
}
return 0;
}
/*
* Write bytes in place to a given property of the given node.
* Any number of bytes of the property can be written.
* Returns 0 on success, and < 0 on error.
*/
int fdtw_write_inplace_bytes(void *dtb, int node, const char *prop,
unsigned int length, const void *data)
{
const void *ptr;
int namelen, value_len, err;
assert(dtb != NULL);
assert(prop != NULL);
assert(data != NULL);
assert(node >= 0);
namelen = (int)strlen(prop);
/* Access property and obtain its length in bytes */
ptr = fdt_getprop_namelen(dtb, node, prop, namelen, &value_len);
if (ptr == NULL) {
WARN("Couldn't find property %s in dtb\n", prop);
return -1;
}
/* Verify that property length is not less than number of bytes */
if ((unsigned int)value_len < length) {
WARN("Property length mismatch\n");
return -1;
}
/* Set property value in place */
err = fdt_setprop_inplace_namelen_partial(dtb, node, prop,
namelen, 0,
data, (int)length);
if (err != 0) {
WARN("Set property %s failed with error %d\n", prop, err);
}
return err;
}
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