rt-thread-official/components/drivers/ofw/fdt.c

1108 lines
27 KiB
C
Executable File

/*
* Copyright (c) 2006-2022, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2022-08-25 GuEe-GUI first version
*/
#include <rthw.h>
#include <rtthread.h>
#include <drivers/ofw_fdt.h>
#include <drivers/ofw_raw.h>
#include <drivers/core/dm.h>
#define DBG_TAG "rtdm.ofw"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#include "ofw_internal.h"
struct rt_fdt_earlycon fdt_earlycon rt_section(".bss.noclean.earlycon");
RT_OFW_SYMBOL_TYPE_RANGE(earlycon, struct rt_fdt_earlycon_id, _earlycon_start = {}, _earlycon_end = {});
#ifndef ARCH_INIT_MEMREGION_NR
#define ARCH_INIT_MEMREGION_NR 128
#endif
static rt_region_t _memregion[ARCH_INIT_MEMREGION_NR] rt_section(".bss.noclean.memregion");
static int _memregion_front_idx = 0, _memregion_last_idx = RT_ARRAY_SIZE(_memregion) - 1;
static void *_fdt = RT_NULL;
static rt_phandle _phandle_min;
static rt_phandle _phandle_max;
static rt_size_t _root_size_cells;
static rt_size_t _root_addr_cells;
const char *rt_fdt_node_name(const char *full_name)
{
const char *node_name = rt_strrchr(full_name, '/');
return node_name ? node_name + 1 : full_name;
}
rt_uint64_t rt_fdt_read_number(const fdt32_t *cell, int size)
{
rt_uint64_t val = 0;
for (; size--; ++cell)
{
val = (val << 32) | fdt32_to_cpu(*cell);
}
return val;
}
rt_uint64_t rt_fdt_next_cell(const fdt32_t **cellptr, int size)
{
const fdt32_t *ptr = *cellptr;
*cellptr = ptr + size;
return rt_fdt_read_number(ptr, size);
}
rt_uint64_t rt_fdt_translate_address(void *fdt, int nodeoffset, rt_uint64_t address)
{
rt_uint64_t ret = address;
if (fdt && nodeoffset >= 0)
{
struct
{
rt_uint64_t addr;
rt_size_t size;
int addr_cells;
int size_cells;
} local, cpu;
int parent, length = 0, group_len;
const fdt32_t *ranges = RT_NULL;
parent = fdt_parent_offset(fdt, nodeoffset);
if (parent >= 0)
{
ranges = fdt_getprop(fdt, nodeoffset, "ranges", &length);
}
if (ranges && length > 0)
{
local.addr_cells = fdt_address_cells(fdt, nodeoffset);
local.size_cells = fdt_size_cells(fdt, nodeoffset);
cpu.addr_cells = fdt_io_addr_cells(fdt, nodeoffset);
cpu.size_cells = fdt_io_size_cells(fdt, nodeoffset);
group_len = local.addr_cells + cpu.addr_cells + local.size_cells;
while (length > 0)
{
local.addr = rt_fdt_next_cell(&ranges, local.addr_cells);
cpu.addr = rt_fdt_next_cell(&ranges, cpu.addr_cells);
local.size = rt_fdt_next_cell(&ranges, local.size_cells);
if (local.addr <= address && local.addr + local.size > address)
{
ret += address - cpu.addr;
break;
}
length -= group_len;
}
}
}
return ret;
}
rt_bool_t rt_fdt_device_is_available(void *fdt, int nodeoffset)
{
rt_bool_t ret;
const char *status = fdt_getprop(fdt, nodeoffset, "status", RT_NULL);
if (!status)
{
ret = RT_TRUE;
}
else if (!rt_strcmp(status, "ok") || !rt_strcmp(status, "okay"))
{
ret = RT_TRUE;
}
else
{
ret = RT_FALSE;
}
return ret;
}
rt_err_t rt_fdt_commit_memregion_early(rt_region_t *region, rt_bool_t is_reserved)
{
rt_err_t err = RT_EOK;
if (region && region->name)
{
if (_memregion_front_idx < _memregion_last_idx)
{
int idx;
if (!_memregion_front_idx && _memregion_last_idx == RT_ARRAY_SIZE(_memregion) - 1)
{
for (int i = 0; i < RT_ARRAY_SIZE(_memregion); ++i)
{
_memregion[i].name = RT_NULL;
}
}
idx = is_reserved ? _memregion_last_idx-- : _memregion_front_idx++;
rt_memcpy(&_memregion[idx], region, sizeof(*region));
}
else
{
err = -RT_EEMPTY;
}
}
else
{
err = -RT_EINVAL;
}
return err;
}
rt_err_t rt_fdt_commit_memregion_request(rt_region_t **out_region, rt_size_t *out_nr, rt_bool_t is_reserved)
{
rt_err_t err = RT_EOK;
if (out_region && out_nr)
{
if (is_reserved)
{
*out_region = &_memregion[_memregion_last_idx + 1];
*out_nr = RT_ARRAY_SIZE(_memregion) - 1 - _memregion_last_idx;
}
else
{
*out_region = &_memregion[0];
*out_nr = _memregion_front_idx;
}
if (*out_nr == 0)
{
err = -RT_EEMPTY;
}
}
else
{
err = -RT_EINVAL;
}
return err;
}
rt_err_t rt_fdt_prefetch(void *fdt)
{
rt_err_t err = -RT_ERROR;
if (fdt)
{
_fdt = fdt;
if (!fdt_check_header(_fdt))
{
err = rt_fdt_scan_root();
}
else
{
err = -RT_EINVAL;
}
}
return err;
}
rt_err_t rt_fdt_scan_root(void)
{
rt_err_t err = RT_EOK;
int root = fdt_path_offset(_fdt, "/");
if (root >= 0)
{
const fdt32_t *prop;
_root_addr_cells = OFW_ROOT_NODE_ADDR_CELLS_DEFAULT;
_root_size_cells = OFW_ROOT_NODE_SIZE_CELLS_DEFAULT;
if ((prop = fdt_getprop(_fdt, root, "#address-cells", RT_NULL)))
{
_root_addr_cells = fdt32_to_cpu(*prop);
}
if ((prop = fdt_getprop(_fdt, root, "#size-cells", RT_NULL)))
{
_root_size_cells = fdt32_to_cpu(*prop);
}
}
else
{
err = -RT_EEMPTY;
}
return err;
}
rt_inline rt_err_t commit_memregion(const char *name, rt_uint64_t base, rt_uint64_t size, rt_bool_t is_reserved)
{
return rt_fdt_commit_memregion_early(&(rt_region_t)
{
.name = name,
.start = (rt_size_t)base,
.end = (rt_size_t)(base + size),
}, is_reserved);
}
static rt_err_t reserve_memregion(const char *name, rt_uint64_t base, rt_uint64_t size)
{
if (commit_memregion(name, base, size, RT_TRUE) == -RT_EEMPTY)
{
LOG_W("Reserved memory: %p - %p%s", base, base + size, " unable to record");
}
return RT_EOK;
}
static rt_err_t fdt_reserved_mem_check_root(int nodeoffset)
{
rt_err_t err = RT_EOK;
const fdt32_t *prop = fdt_getprop(_fdt, nodeoffset, "#size-cells", RT_NULL);
if (!prop || fdt32_to_cpu(*prop) != _root_size_cells)
{
err = -RT_EINVAL;
}
if (!err)
{
prop = fdt_getprop(_fdt, nodeoffset, "#address-cells", RT_NULL);
if (!prop || fdt32_to_cpu(*prop) != _root_addr_cells)
{
err = -RT_EINVAL;
}
}
if (!err && !(prop = fdt_getprop(_fdt, nodeoffset, "ranges", RT_NULL)))
{
err = -RT_EINVAL;
}
return err;
}
static rt_err_t fdt_reserved_memory_reg(int nodeoffset, const char *uname)
{
rt_err_t err = RT_EOK;
rt_ubase_t base, size;
const fdt32_t *prop;
int len, t_len = (_root_addr_cells + _root_size_cells) * sizeof(fdt32_t);
if ((prop = fdt_getprop(_fdt, nodeoffset, "reg", &len)))
{
if (len && len % t_len != 0)
{
LOG_E("Reserved memory: invalid reg property in '%s', skipping node", uname);
err = -RT_EINVAL;
}
else
{
while (len >= t_len)
{
base = rt_fdt_next_cell(&prop, _root_addr_cells);
size = rt_fdt_next_cell(&prop, _root_size_cells);
if (!size)
{
continue;
}
base = rt_fdt_translate_address(_fdt, nodeoffset, base);
reserve_memregion(fdt_get_name(_fdt, nodeoffset, RT_NULL), base, size);
len -= t_len;
}
}
}
else
{
err = -RT_EEMPTY;
}
return err;
}
static void fdt_scan_reserved_memory(void)
{
int nodeoffset, child;
nodeoffset = fdt_path_offset(_fdt, "/reserved-memory");
if (nodeoffset >= 0)
{
if (!fdt_reserved_mem_check_root(nodeoffset))
{
fdt_for_each_subnode(child, _fdt, nodeoffset)
{
rt_err_t err;
const char *uname;
if (!rt_fdt_device_is_available(_fdt, child))
{
continue;
}
uname = fdt_get_name(_fdt, child, RT_NULL);
err = fdt_reserved_memory_reg(child, uname);
if (err == -RT_EEMPTY && fdt_getprop(_fdt, child, "size", RT_NULL))
{
reserve_memregion(fdt_get_name(_fdt, child, RT_NULL), 0, 0);
}
}
}
else
{
LOG_E("Reserved memory: unsupported node format, ignoring");
}
}
}
static rt_err_t fdt_scan_memory(void)
{
int nodeoffset, no;
rt_region_t *region;
rt_uint64_t base, size;
rt_err_t err = -RT_EEMPTY;
/* Process header /memreserve/ fields */
for (no = 0; ; ++no)
{
fdt_get_mem_rsv(_fdt, no, &base, &size);
if (!size)
{
break;
}
reserve_memregion("memreserve", base, size);
}
no = 0;
fdt_for_each_subnode(nodeoffset, _fdt, 0)
{
int len;
const fdt32_t *reg, *endptr;
const char *name = fdt_get_name(_fdt, nodeoffset, RT_NULL);
const char *type = fdt_getprop(_fdt, nodeoffset, "device_type", RT_NULL);
if (!type || rt_strcmp(type, "memory"))
{
continue;
}
if (!rt_fdt_device_is_available(_fdt, nodeoffset))
{
continue;
}
reg = fdt_getprop(_fdt, nodeoffset, "reg", &len);
if (!reg)
{
continue;
}
endptr = reg + (len / sizeof(fdt32_t));
name = name ? name : "memory";
while ((endptr - reg) >= (_root_addr_cells + _root_size_cells))
{
base = rt_fdt_next_cell(&reg, _root_addr_cells);
size = rt_fdt_next_cell(&reg, _root_size_cells);
if (!size)
{
continue;
}
err = commit_memregion(name, base, size, RT_FALSE);
if (!err)
{
LOG_I("Memory node(%d) ranges: %p - %p%s", no, base, base + size, "");
}
else
{
LOG_W("Memory node(%d) ranges: %p - %p%s", no, base, base + size, " unable to record");
}
++no;
}
}
if (!err)
{
fdt_scan_reserved_memory();
}
region = &_memregion[0];
for (no = 0; region->name; ++region)
{
/* We need check the memory region now. */
for (int i = RT_ARRAY_SIZE(_memregion) - 1; i > no; --i)
{
rt_region_t *res_region = &_memregion[i];
if (!res_region->name)
{
break;
}
/*
* case 0: case 1:
* +------------------+ +----------+
* | memory | | memory |
* +---+----------+---+ +---+----------+---+
* | reserved | | reserved |
* +----------+ +---+----------+---+
*
* case 2: case 3:
* +------------------+ +------------------+
* | memory | | memory |
* +--------------+---+------+ +------+---+--------------+
* | reserved | | reserved |
* +----------+ +----------+
*/
/* case 0 */
if (res_region->start >= region->start && res_region->end <= region->end)
{
rt_size_t new_size = region->end - res_region->end;
region->end = res_region->start;
/* Commit part next block */
if (new_size)
{
err = commit_memregion(region->name, res_region->end, new_size, RT_FALSE);
}
if (!err)
{
++no;
/* Scan again */
region = &_memregion[0];
--region;
break;
}
continue;
}
/* case 1 */
if (res_region->start <= region->start && res_region->end >= region->end)
{
region->name = RT_NULL;
break;
}
/* case 2 */
if (res_region->start <= region->end && res_region->end >= region->end)
{
region->end = res_region->start;
continue;
}
/* case 3 */
if (res_region->start <= region->start && res_region->end >= region->start)
{
region->start = res_region->end;
continue;
}
}
}
return err;
}
rt_err_t rt_fdt_scan_memory(void)
{
rt_err_t err = -RT_EEMPTY;
if (_fdt)
{
err = fdt_scan_memory();
}
return err;
}
rt_err_t rt_fdt_scan_initrd(rt_uint64_t *ranges)
{
rt_err_t err = -RT_EEMPTY;
if (_fdt && ranges)
{
int s_len, e_len;
const fdt32_t *start = RT_NULL, *end = RT_NULL;
int offset = fdt_path_offset(_fdt, "/chosen");
if (offset >= 0)
{
start = fdt_getprop(_fdt, offset, "linux,initrd-start", &s_len);
end = fdt_getprop(_fdt, offset, "linux,initrd-end", &e_len);
}
if (start && end)
{
s_len /= sizeof(*start);
e_len /= sizeof(*end);
ranges[0] = rt_fdt_read_number(start, s_len);
ranges[1] = rt_fdt_read_number(end, e_len);
commit_memregion("initrd", ranges[0], ranges[1] - ranges[0], RT_TRUE);
err = RT_EOK;
}
}
else if (!ranges)
{
err = -RT_EINVAL;
}
return err;
}
rt_err_t rt_fdt_model_dump(void)
{
rt_err_t err = RT_EOK;
int root = fdt_path_offset(_fdt, "/");
if (root >= 0)
{
const char *mach_model = fdt_getprop(_fdt, root, "model", RT_NULL);
if (!mach_model)
{
mach_model = fdt_getprop(_fdt, root, "compatible", RT_NULL);
}
LOG_I("Machine model: %s", mach_model ? mach_model : "<undefined>");
}
else
{
err = -RT_EEMPTY;
}
return err;
}
rt_weak rt_err_t rt_fdt_boot_dump(void)
{
LOG_I("Booting RT-Thread on physical CPU 0x%x", rt_hw_cpu_id());
return RT_EOK;
}
void rt_fdt_earlycon_output(const char *str)
{
if (fdt_earlycon.console_putc)
{
while (*str)
{
fdt_earlycon.console_putc(fdt_earlycon.data, *str);
if (*str == '\n')
{
/* Make sure return */
fdt_earlycon.console_putc(fdt_earlycon.data, '\r');
}
++str;
}
}
else
{
/* We need a byte to save '\0' */
while (*str && fdt_earlycon.msg_idx < sizeof(fdt_earlycon.msg) - 1)
{
fdt_earlycon.msg[fdt_earlycon.msg_idx++] = *str;
++str;
}
fdt_earlycon.msg[fdt_earlycon.msg_idx] = '\0';
}
}
void rt_fdt_earlycon_kick(int why)
{
if (fdt_earlycon.console_kick)
{
fdt_earlycon.console_kick(&fdt_earlycon, why);
}
if (why == FDT_EARLYCON_KICK_COMPLETED && fdt_earlycon.msg_idx)
{
fdt_earlycon.msg_idx = 0;
/* Dump old messages */
rt_kputs(fdt_earlycon.msg);
}
}
rt_err_t rt_fdt_scan_chosen_stdout(void)
{
rt_err_t err = RT_EOK;
int offset;
int len, options_len = 0;
const char *options = RT_NULL, *con_type = RT_NULL;
rt_memset(&fdt_earlycon, 0, sizeof(fdt_earlycon) - sizeof(fdt_earlycon.msg));
fdt_earlycon.nodeoffset = -1;
offset = fdt_path_offset(_fdt, "/chosen");
if (offset >= 0)
{
const char *stdout_path = RT_NULL;
const char *bootargs = fdt_getprop(_fdt, offset, "bootargs", &len);
if (bootargs && (options = rt_strstr(bootargs, "earlycon")))
{
options += sizeof("earlycon") - 1;
if (*options == '\0' || *options == ' ')
{
stdout_path = fdt_getprop(_fdt, offset, "stdout-path", &len);
if (stdout_path && len)
{
const char *path_split = rt_strchrnul(stdout_path, ':');
if (*path_split != '\0')
{
options = path_split + 1;
}
len = path_split - stdout_path;
/*
* Will try 2 styles:
* 1: stdout-path = "serialN:bbbbpnf";
* 2: stdout-path = "/serial-path";
*/
offset = fdt_path_offset_namelen(_fdt, stdout_path, len);
if (offset < 0)
{
stdout_path = RT_NULL;
}
}
else if (*options == '=')
{
++options;
}
else
{
/* Maybe is error in bootargs or it is a new arg */
options = RT_NULL;
}
if (!stdout_path)
{
/* We couldn't know how to setup the earlycon */
options = RT_NULL;
}
}
else
{
offset = -1;
}
if (options)
{
int type_len = 0;
struct rt_fdt_earlycon_id *earlycon_id, *earlycon_id_end, *best_earlycon_id = RT_NULL;
earlycon_id = (struct rt_fdt_earlycon_id *)&_earlycon_start;
earlycon_id_end = (struct rt_fdt_earlycon_id *)&_earlycon_end;
err = -RT_ENOSYS;
/* Only "earlycon" in bootargs */
if (stdout_path)
{
const fdt32_t *reg;
options = RT_NULL;
if ((reg = fdt_getprop(_fdt, offset, "reg", RT_NULL)))
{
rt_uint64_t address;
int addr_cells = fdt_io_addr_cells(_fdt, offset);
int size_cells = fdt_io_size_cells(_fdt, offset);
address = rt_fdt_read_number(reg, addr_cells);
fdt_earlycon.mmio = rt_fdt_translate_address(_fdt, offset, address);
fdt_earlycon.size = rt_fdt_read_number(reg + addr_cells, size_cells);
}
}
else
{
/* Pass split */
while (*options && (*options == '=' || *options == ' '))
{
++options;
}
if (*options)
{
type_len = rt_strchrnul(options, ',') - options;
}
}
if (options && *options && *options != ' ')
{
options_len = rt_strchrnul(options, ' ') - options;
}
/* console > stdout-path */
for (int max_score = 0; earlycon_id < earlycon_id_end; ++earlycon_id)
{
int score = 0;
if (type_len && earlycon_id->type)
{
if (!rt_strncmp(earlycon_id->type, options, type_len))
{
score += 1;
}
}
if (stdout_path && earlycon_id->compatible)
{
if (!fdt_node_check_compatible(_fdt, offset, earlycon_id->compatible))
{
score += 2;
}
}
if (score > max_score)
{
max_score = score;
best_earlycon_id = earlycon_id;
if (score == 3)
{
break;
}
}
}
if (best_earlycon_id && best_earlycon_id->setup)
{
rt_bool_t used_options = RT_FALSE;
if (!con_type)
{
con_type = best_earlycon_id->type;
}
fdt_earlycon.fdt = _fdt;
fdt_earlycon.nodeoffset = offset;
err = best_earlycon_id->setup(&fdt_earlycon, options);
for (int i = 0; i < options_len; ++i)
{
if (options[i] == RT_FDT_EARLYCON_OPTION_SIGNATURE)
{
/* Restore ',' */
((char *)options)[i++] = ',';
options = &options[i];
options_len -= i;
used_options = RT_TRUE;
break;
}
}
if (!used_options)
{
options = RT_NULL;
options_len = 0;
}
}
}
}
else
{
err = -RT_EEMPTY;
}
}
else
{
err = -RT_EEMPTY;
}
if (fdt_earlycon.msg_idx)
{
fdt_earlycon.msg_idx = 0;
rt_kputs(fdt_earlycon.msg);
}
rt_fdt_boot_dump();
rt_fdt_model_dump();
if (fdt_earlycon.mmio)
{
LOG_I("Earlycon: %s at MMIO/PIO %p (options '%.*s')",
con_type, fdt_earlycon.mmio, options_len, options ? options : "");
}
return err;
}
static void system_node_init_flag(struct rt_ofw_node *np)
{
if (np)
{
rt_ofw_node_set_flag(np, RT_OFW_F_READLY);
rt_ofw_node_set_flag(np, RT_OFW_F_SYSTEM);
}
}
rt_err_t rt_fdt_unflatten(void)
{
rt_err_t err = RT_EOK;
if (_fdt)
{
_phandle_min = OFW_PHANDLE_MAX;
_phandle_max = OFW_PHANDLE_MIN;
ofw_node_root = rt_fdt_unflatten_single(_fdt);
if (ofw_node_root)
{
ofw_node_cpus = rt_ofw_find_node_by_path("/cpus");
ofw_node_chosen = rt_ofw_find_node_by_path("/chosen");
ofw_node_aliases = rt_ofw_find_node_by_path("/aliases");
ofw_node_reserved_memory = rt_ofw_find_node_by_path("/reserved-memory");
RT_ASSERT(ofw_node_cpus != RT_NULL);
system_node_init_flag(ofw_node_root);
system_node_init_flag(ofw_node_cpus);
system_node_init_flag(ofw_node_chosen);
system_node_init_flag(ofw_node_aliases);
system_node_init_flag(ofw_node_reserved_memory);
if (ofw_node_aliases)
{
err = ofw_alias_scan();
}
err = err ? : ofw_phandle_hash_reset(_phandle_min, _phandle_max);
}
}
else
{
err = -RT_ERROR;
}
return err;
}
static rt_err_t fdt_unflatten_props(struct rt_ofw_node *np, int node_off)
{
rt_err_t err = RT_EOK;
struct rt_ofw_prop *prop;
int prop_off = fdt_first_property_offset(_fdt, node_off);
if (prop_off >= 0)
{
np->props = rt_malloc(sizeof(struct rt_ofw_prop));
}
prop = np->props;
while (prop_off >= 0)
{
if (!prop)
{
err = -RT_ENOMEM;
break;
}
prop->value = (void *)fdt_getprop_by_offset(_fdt, prop_off, &prop->name, &prop->length);
if (prop->name && !rt_strcmp(prop->name, "name"))
{
np->name = prop->value;
}
prop_off = fdt_next_property_offset(_fdt, prop_off);
if (prop_off < 0)
{
prop->next = RT_NULL;
break;
}
prop->next = rt_malloc(sizeof(struct rt_ofw_prop));
prop = prop->next;
}
return err;
}
static rt_err_t fdt_unflatten_single(struct rt_ofw_node *np, int node_off)
{
int depth = 0;
rt_err_t err = RT_EOK;
struct rt_ofw_node *np_stack[OFW_NODE_MAX_DEPTH], *parent = RT_NULL;
do {
if (!np)
{
err = -RT_ENOMEM;
break;
}
np->name = "<NULL>";
np->full_name = fdt_get_name(_fdt, node_off, RT_NULL);
np->phandle = fdt_get_phandle(_fdt, node_off);
if (np->phandle >= OFW_PHANDLE_MIN)
{
if (np->phandle < _phandle_min)
{
_phandle_min = np->phandle;
}
if (np->phandle > _phandle_max)
{
_phandle_max = np->phandle;
}
}
if ((err = fdt_unflatten_props(np, node_off)))
{
break;
}
np->parent = parent;
rt_ref_init(&np->ref);
np->flags = 0;
if (!np->child)
{
/* Save node offset temp */
rt_ofw_data(np) = (void *)(rt_ubase_t)node_off;
/* Check children */
node_off = fdt_first_subnode(_fdt, node_off);
if (node_off >= 0)
{
parent = np;
np_stack[depth++] = np;
np->child = rt_calloc(1, sizeof(struct rt_ofw_node));
np = np->child;
continue;
}
}
while (depth >= 0)
{
/* Restore node offset temp */
node_off = (long)rt_ofw_data(np);
rt_ofw_data(np) = RT_NULL;
/* Next step */
node_off = fdt_next_subnode(_fdt, node_off);
if (node_off < 0)
{
np->sibling = RT_NULL;
np = np_stack[--depth];
}
else
{
parent = np->parent;
np->sibling = rt_calloc(1, sizeof(struct rt_ofw_node));
np = np->sibling;
break;
}
}
} while (depth >= 0);
return err;
}
struct rt_ofw_node *rt_fdt_unflatten_single(void *fdt)
{
int root_off;
struct fdt_info *header;
struct rt_ofw_node *root = RT_NULL;
if (fdt && (root_off = fdt_path_offset(fdt, "/")) >= 0)
{
root = rt_calloc(1, sizeof(struct fdt_info) + sizeof(struct rt_ofw_node));
}
if (root)
{
header = (void *)root + sizeof(struct rt_ofw_node);
rt_strncpy(header->name, "/", sizeof("/"));
header->fdt = fdt;
header->rsvmap = (struct fdt_reserve_entry *)((void *)fdt + fdt_off_mem_rsvmap(fdt));
header->rsvmap_nr = fdt_num_mem_rsv(fdt);
if (!fdt_unflatten_single(root, root_off))
{
root->name = (const char *)header;
}
else
{
rt_ofw_node_destroy(root);
root = RT_NULL;
}
}
return root;
}