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# Copyright (C) 2016 Google, Inc
# Written by Simon Glass <>
# SPDX-License-Identifier: GPL-2.0+
import copy
from optparse import OptionError, OptionParser
import os
import struct
import sys
# Bring in the patman libraries
our_path = os.path.dirname(os.path.realpath(__file__))
sys.path.append(os.path.join(our_path, '../patman'))
import fdt
import fdt_select
import fdt_util
# When we see these properties we ignore them - i.e. do not create a structure member
# C type declarations for the tyues we support
fdt.TYPE_INT: 'fdt32_t',
fdt.TYPE_BYTE: 'unsigned char',
fdt.TYPE_STRING: 'const char *',
fdt.TYPE_BOOL: 'bool',
VAL_PREFIX = 'dtv_'
def Conv_name_to_c(name):
"""Convert a device-tree name to a C identifier
name: Name to convert
String containing the C version of this name
str = name.replace('@', '_at_')
str = str.replace('-', '_')
str = str.replace(',', '_')
str = str.replace('.', '_')
str = str.replace('/', '__')
return str
def TabTo(num_tabs, str):
if len(str) >= num_tabs * 8:
return str + ' '
return str + '\t' * (num_tabs - len(str) // 8)
class DtbPlatdata:
"""Provide a means to convert device tree binary data to platform data
The output of this process is C structures which can be used in space-
constrained encvironments where the ~3KB code overhead of device tree
code is not affordable.
fdt: Fdt object, referencing the device tree
_dtb_fname: Filename of the input device tree binary file
_valid_nodes: A list of Node object with compatible strings
_options: Command-line options
_phandle_node: A dict of nodes indexed by phandle number (1, 2...)
_outfile: The current output file (sys.stdout or a real file)
_lines: Stashed list of output lines for outputting in the future
_phandle_node: A dict of Nodes indexed by phandle (an integer)
def __init__(self, dtb_fname, options):
self._dtb_fname = dtb_fname
self._valid_nodes = None
self._options = options
self._phandle_node = {}
self._outfile = None
self._lines = []
def SetupOutput(self, fname):
"""Set up the output destination
Once this is done, future calls to self.Out() will output to this
fname: Filename to send output to, or '-' for stdout
if fname == '-':
self._outfile = sys.stdout
self._outfile = open(fname, 'w')
def Out(self, str):
"""Output a string to the output file
str: String to output
def Buf(self, str):
"""Buffer up a string to send later
str: String to add to our 'buffer' list
def GetBuf(self):
"""Get the contents of the output buffer, and clear it
The output buffer, which is then cleared for future use
lines = self._lines
self._lines = []
return lines
def GetValue(self, type, value):
"""Get a value as a C expression
For integers this returns a byte-swapped (little-endian) hex string
For bytes this returns a hex string, e.g. 0x12
For strings this returns a literal string enclosed in quotes
For booleans this return 'true'
type: Data type (fdt_util)
value: Data value, as a string of bytes
if type == fdt.TYPE_INT:
return '%#x' % fdt_util.fdt32_to_cpu(value)
elif type == fdt.TYPE_BYTE:
return '%#x' % ord(value[0])
elif type == fdt.TYPE_STRING:
return '"%s"' % value
elif type == fdt.TYPE_BOOL:
return 'true'
def GetCompatName(self, node):
"""Get a node's first compatible string as a C identifier
node: Node object to check
C identifier for the first compatible string
compat = node.props['compatible'].value
if type(compat) == list:
compat = compat[0]
return Conv_name_to_c(compat)
def ScanDtb(self):
"""Scan the device tree to obtain a tree of notes and properties
Once this is done, self.fdt.GetRoot() can be called to obtain the
device tree root node, and progress from there.
self.fdt = fdt_select.FdtScan(self._dtb_fname)
def ScanTree(self):
"""Scan the device tree for useful information
This fills in the following properties:
_phandle_node: A dict of Nodes indexed by phandle (an integer)
_valid_nodes: A list of nodes we wish to consider include in the
platform data
node_list = []
self._phandle_node = {}
for node in self.fdt.GetRoot().subnodes:
if 'compatible' in node.props:
status = node.props.get('status')
if (not options.include_disabled and not status or
status.value != 'disabled'):
phandle_prop = node.props.get('phandle')
if phandle_prop:
phandle = phandle_prop.GetPhandle()
self._phandle_node[phandle] = node
self._valid_nodes = node_list
def IsPhandle(self, prop):
"""Check if a node contains phandles
We have no reliable way of detecting whether a node uses a phandle
or not. As an interim measure, use a list of known property names.
prop: Prop object to check
True if the object value contains phandles, else False
if in ['clocks']:
return True
return False
def ScanStructs(self):
"""Scan the device tree building up the C structures we will use.
Build a dict keyed by C struct name containing a dict of Prop
object for each struct field (keyed by property name). Where the
same struct appears multiple times, try to use the 'widest'
property, i.e. the one with a type which can express all others.
Once the widest property is determined, all other properties are
updated to match that width.
structs = {}
for node in self._valid_nodes:
node_name = self.GetCompatName(node)
fields = {}
# Get a list of all the valid properties in this node.
for name, prop in node.props.items():
if name not in PROP_IGNORE_LIST and name[0] != '#':
fields[name] = copy.deepcopy(prop)
# If we've seen this node_name before, update the existing struct.
if node_name in structs:
struct = structs[node_name]
for name, prop in fields.items():
oldprop = struct.get(name)
if oldprop:
struct[name] = prop
# Otherwise store this as a new struct.
structs[node_name] = fields
upto = 0
for node in self._valid_nodes:
node_name = self.GetCompatName(node)
struct = structs[node_name]
for name, prop in node.props.items():
if name not in PROP_IGNORE_LIST and name[0] != '#':
upto += 1
return structs
def GenerateStructs(self, structs):
"""Generate struct defintions for the platform data
This writes out the body of a header file consisting of structure
definitions for node in self._valid_nodes. See the documentation in
README.of-plat for more information.
self.Out('#include <stdbool.h>\n')
self.Out('#include <libfdt.h>\n')
# Output the struct definition
for name in sorted(structs):
self.Out('struct %s%s {\n' % (STRUCT_PREFIX, name));
for pname in sorted(structs[name]):
prop = structs[name][pname]
if self.IsPhandle(prop):
# For phandles, include a reference to the target
self.Out('\t%s%s[%d]' % (TabTo(2, 'struct phandle_2_cell'),
len(prop.value) / 2))
ptype = TYPE_NAMES[prop.type]
self.Out('\t%s%s' % (TabTo(2, ptype),
if type(prop.value) == list:
self.Out('[%d]' % len(prop.value))
def GenerateTables(self):
"""Generate device defintions for the platform data
This writes out C platform data initialisation data and
U_BOOT_DEVICE() declarations for each valid node. See the
documentation in README.of-plat for more information.
self.Out('#include <common.h>\n')
self.Out('#include <dm.h>\n')
self.Out('#include <dt-structs.h>\n')
node_txt_list = []
for node in self._valid_nodes:
struct_name = self.GetCompatName(node)
var_name = Conv_name_to_c(
self.Buf('static struct %s%s %s%s = {\n' %
(STRUCT_PREFIX, struct_name, VAL_PREFIX, var_name))
for pname, prop in node.props.items():
if pname in PROP_IGNORE_LIST or pname[0] == '#':
ptype = TYPE_NAMES[prop.type]
member_name = Conv_name_to_c(
self.Buf('\t%s= ' % TabTo(3, '.' + member_name))
# Special handling for lists
if type(prop.value) == list:
vals = []
# For phandles, output a reference to the platform data
# of the target node.
if self.IsPhandle(prop):
# Process the list as pairs of (phandle, id)
it = iter(prop.value)
for phandle_cell, id_cell in zip(it, it):
phandle = fdt_util.fdt32_to_cpu(phandle_cell)
id = fdt_util.fdt32_to_cpu(id_cell)
target_node = self._phandle_node[phandle]
name = Conv_name_to_c(
vals.append('{&%s%s, %d}' % (VAL_PREFIX, name, id))
for val in prop.value:
vals.append(self.GetValue(prop.type, val))
self.Buf(', '.join(vals))
self.Buf(self.GetValue(prop.type, prop.value))
# Add a device declaration
self.Buf('U_BOOT_DEVICE(%s) = {\n' % var_name)
self.Buf('\\t\t= "%s",\n' % struct_name)
self.Buf('\t.platdata\t= &%s%s,\n' % (VAL_PREFIX, var_name))
self.Buf('\t.platdata_size\t= sizeof(%s%s),\n' %
(VAL_PREFIX, var_name))
# Output phandle target nodes first, since they may be referenced
# by others
if 'phandle' in node.props:
# Output all the nodes which are not phandle targets themselves, but
# may reference them. This avoids the need for forward declarations.
for node_txt in node_txt_list:
if __name__ != "__main__":
parser = OptionParser()
parser.add_option('-d', '--dtb-file', action='store',
help='Specify the .dtb input file')
parser.add_option('--include-disabled', action='store_true',
help='Include disabled nodes')
parser.add_option('-o', '--output', action='store', default='-',
help='Select output filename')
(options, args) = parser.parse_args()
if not args:
raise ValueError('Please specify a command: struct, platdata')
plat = DtbPlatdata(options.dtb_file, options)
structs = plat.ScanStructs()
for cmd in args[0].split(','):
if cmd == 'struct':
elif cmd == 'platdata':
raise ValueError("Unknown command '%s': (use: struct, platdata)" % cmd)