u-boot/tools/dtoc/dtb_platdata.py

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#!/usr/bin/python
#
# Copyright (C) 2017 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# SPDX-License-Identifier: GPL-2.0+
#
"""Device tree to platform data class
This supports converting device tree data to C structures definitions and
static data.
"""
import copy
import sys
import fdt
import fdt_util
# When we see these properties we ignore them - i.e. do not create a structure member
PROP_IGNORE_LIST = [
'#address-cells',
'#gpio-cells',
'#size-cells',
'compatible',
'linux,phandle',
"status",
'phandle',
'u-boot,dm-pre-reloc',
'u-boot,dm-tpl',
'u-boot,dm-spl',
]
# C type declarations for the tyues we support
TYPE_NAMES = {
fdt.TYPE_INT: 'fdt32_t',
fdt.TYPE_BYTE: 'unsigned char',
fdt.TYPE_STRING: 'const char *',
fdt.TYPE_BOOL: 'bool',
}
STRUCT_PREFIX = 'dtd_'
VAL_PREFIX = 'dtv_'
def conv_name_to_c(name):
"""Convert a device-tree name to a C identifier
This uses multiple replace() calls instead of re.sub() since it is faster
(400ms for 1m calls versus 1000ms for the 're' version).
Args:
name: Name to convert
Return:
String containing the C version of this name
"""
new = name.replace('@', '_at_')
new = new.replace('-', '_')
new = new.replace(',', '_')
new = new.replace('.', '_')
return new
def tab_to(num_tabs, line):
"""Append tabs to a line of text to reach a tab stop.
Args:
num_tabs: Tab stop to obtain (0 = column 0, 1 = column 8, etc.)
line: Line of text to append to
Returns:
line with the correct number of tabs appeneded. If the line already
extends past that tab stop then a single space is appended.
"""
if len(line) >= num_tabs * 8:
return line + ' '
return line + '\t' * (num_tabs - len(line) // 8)
def get_value(ftype, 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'
Args:
type: Data type (fdt_util)
value: Data value, as a string of bytes
"""
if ftype == fdt.TYPE_INT:
return '%#x' % fdt_util.fdt32_to_cpu(value)
elif ftype == fdt.TYPE_BYTE:
return '%#x' % ord(value[0])
elif ftype == fdt.TYPE_STRING:
return '"%s"' % value
elif ftype == fdt.TYPE_BOOL:
return 'true'
def get_compat_name(node):
"""Get a node's first compatible string as a C identifier
Args:
node: Node object to check
Return:
Tuple:
C identifier for the first compatible string
List of C identifiers for all the other compatible strings
(possibly empty)
"""
compat = node.props['compatible'].value
aliases = []
if isinstance(compat, list):
compat, aliases = compat[0], compat[1:]
return conv_name_to_c(compat), [conv_name_to_c(a) for a in aliases]
def is_phandle(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.
Args:
prop: Prop object to check
Return:
True if the object value contains phandles, else False
"""
if prop.name in ['clocks']:
return True
return False
class DtbPlatdata(object):
"""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.
Properties:
_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
_include_disabled: true to include nodes marked status = "disabled"
_phandle_nodes: 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_nodes: A dict of Nodes indexed by phandle (an integer)
"""
def __init__(self, dtb_fname, include_disabled):
self._fdt = None
self._dtb_fname = dtb_fname
self._valid_nodes = None
self._include_disabled = include_disabled
self._phandle_nodes = {}
self._outfile = None
self._lines = []
self._aliases = {}
def setup_output(self, fname):
"""Set up the output destination
Once this is done, future calls to self.out() will output to this
file.
Args:
fname: Filename to send output to, or '-' for stdout
"""
if fname == '-':
self._outfile = sys.stdout
else:
self._outfile = open(fname, 'w')
def out(self, line):
"""Output a string to the output file
Args:
line: String to output
"""
self._outfile.write(line)
def buf(self, line):
"""Buffer up a string to send later
Args:
line: String to add to our 'buffer' list
"""
self._lines.append(line)
def get_buf(self):
"""Get the contents of the output buffer, and clear it
Returns:
The output buffer, which is then cleared for future use
"""
lines = self._lines
self._lines = []
return lines
def scan_dtb(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.FdtScan(self._dtb_fname)
def scan_node(self, root):
"""Scan a node and subnodes to build a tree of node and phandle info
This adds each node to self._valid_nodes and each phandle to
self._phandle_nodes.
Args:
root: Root node for scan
"""
for node in root.subnodes:
if 'compatible' in node.props:
status = node.props.get('status')
if (not self._include_disabled and not status or
status.value != 'disabled'):
self._valid_nodes.append(node)
phandle_prop = node.props.get('phandle')
if phandle_prop:
phandle = phandle_prop.GetPhandle()
self._phandle_nodes[phandle] = node
# recurse to handle any subnodes
self.scan_node(node)
def scan_tree(self):
"""Scan the device tree for useful information
This fills in the following properties:
_phandle_nodes: A dict of Nodes indexed by phandle (an integer)
_valid_nodes: A list of nodes we wish to consider include in the
platform data
"""
self._phandle_nodes = {}
self._valid_nodes = []
return self.scan_node(self._fdt.GetRoot())
def scan_structs(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, _ = get_compat_name(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:
oldprop.Widen(prop)
else:
struct[name] = prop
# Otherwise store this as a new struct.
else:
structs[node_name] = fields
upto = 0
for node in self._valid_nodes:
node_name, _ = get_compat_name(node)
struct = structs[node_name]
for name, prop in node.props.items():
if name not in PROP_IGNORE_LIST and name[0] != '#':
prop.Widen(struct[name])
upto += 1
struct_name, aliases = get_compat_name(node)
for alias in aliases:
self._aliases[alias] = struct_name
return structs
def scan_phandles(self):
"""Figure out what phandles each node uses
We need to be careful when outputing nodes that use phandles since
they must come after the declaration of the phandles in the C file.
Otherwise we get a compiler error since the phandle struct is not yet
declared.
This function adds to each node a list of phandle nodes that the node
depends on. This allows us to output things in the right order.
"""
for node in self._valid_nodes:
node.phandles = set()
for pname, prop in node.props.items():
if pname in PROP_IGNORE_LIST or pname[0] == '#':
continue
if isinstance(prop.value, list):
if is_phandle(prop):
# Process the list as pairs of (phandle, id)
value_it = iter(prop.value)
for phandle_cell, _ in zip(value_it, value_it):
phandle = fdt_util.fdt32_to_cpu(phandle_cell)
target_node = self._phandle_nodes[phandle]
node.phandles.add(target_node)
def generate_structs(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 is_phandle(prop):
# For phandles, include a reference to the target
self.out('\t%s%s[%d]' % (tab_to(2, 'struct phandle_2_cell'),
conv_name_to_c(prop.name),
len(prop.value) / 2))
else:
ptype = TYPE_NAMES[prop.type]
self.out('\t%s%s' % (tab_to(2, ptype),
conv_name_to_c(prop.name)))
if isinstance(prop.value, list):
self.out('[%d]' % len(prop.value))
self.out(';\n')
self.out('};\n')
for alias, struct_name in self._aliases.iteritems():
self.out('#define %s%s %s%s\n'% (STRUCT_PREFIX, alias,
STRUCT_PREFIX, struct_name))
def output_node(self, node):
"""Output the C code for a node
Args:
node: node to output
"""
struct_name, _ = get_compat_name(node)
var_name = conv_name_to_c(node.name)
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] == '#':
continue
member_name = conv_name_to_c(prop.name)
self.buf('\t%s= ' % tab_to(3, '.' + member_name))
# Special handling for lists
if isinstance(prop.value, list):
self.buf('{')
vals = []
# For phandles, output a reference to the platform data
# of the target node.
if is_phandle(prop):
# Process the list as pairs of (phandle, id)
value_it = iter(prop.value)
for phandle_cell, id_cell in zip(value_it, value_it):
phandle = fdt_util.fdt32_to_cpu(phandle_cell)
id_num = fdt_util.fdt32_to_cpu(id_cell)
target_node = self._phandle_nodes[phandle]
name = conv_name_to_c(target_node.name)
vals.append('{&%s%s, %d}' % (VAL_PREFIX, name, id_num))
else:
for val in prop.value:
vals.append(get_value(prop.type, val))
self.buf(', '.join(vals))
self.buf('}')
else:
self.buf(get_value(prop.type, prop.value))
self.buf(',\n')
self.buf('};\n')
# Add a device declaration
self.buf('U_BOOT_DEVICE(%s) = {\n' % var_name)
self.buf('\t.name\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))
self.buf('};\n')
self.buf('\n')
self.out(''.join(self.get_buf()))
def generate_tables(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. Where a node has
multiple compatible strings, a #define is used to make them equivalent.
See the documentation in doc/driver-model/of-plat.txt for more
information.
"""
self.out('#include <common.h>\n')
self.out('#include <dm.h>\n')
self.out('#include <dt-structs.h>\n')
self.out('\n')
nodes_to_output = list(self._valid_nodes)
# Keep outputing nodes until there is none left
while nodes_to_output:
node = nodes_to_output[0]
# Output all the node's dependencies first
for req_node in node.phandles:
if req_node in nodes_to_output:
self.output_node(req_node)
nodes_to_output.remove(req_node)
self.output_node(node)
nodes_to_output.remove(node)
def run_steps(args, dtb_file, include_disabled, output):
"""Run all the steps of the dtoc tool
Args:
args: List of non-option arguments provided to the problem
dtb_file: Filename of dtb file to process
include_disabled: True to include disabled nodes
output: Name of output file
"""
if not args:
raise ValueError('Please specify a command: struct, platdata')
plat = DtbPlatdata(dtb_file, include_disabled)
plat.scan_dtb()
plat.scan_tree()
plat.setup_output(output)
structs = plat.scan_structs()
plat.scan_phandles()
for cmd in args[0].split(','):
if cmd == 'struct':
plat.generate_structs(structs)
elif cmd == 'platdata':
plat.generate_tables()
else:
raise ValueError("Unknown command '%s': (use: struct, platdata)" %
cmd)