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# Copyright (c) 2019 Nordic Semiconductor ASA
# Copyright (c) 2019 Linaro Limited
# SPDX-License-Identifier: BSD-3-Clause
# Tip: You can view just the documentation with 'pydoc3 edtlib'
"""
Library for working with .dts files and bindings at a higher level compared to
dtlib. Deals with things at the level of devices, registers, interrupts,
compatibles, bindings, etc., as opposed to dtlib, which is just a low-level
device tree parser.
Each device tree node (dtlib.Node) gets a Device instance, which has all the
information related to the device, derived from both the device tree and from
the binding for the device.
Bindings are files that describe device tree nodes. Device tree nodes are
usually mapped to bindings via their 'compatible = "..."' property, but binding
data can also come from a 'sub-node:' key in the binding for the parent device
tree node.
The top-level entry point of the library is the EDT class. EDT.__init__() takes
a .dts file to parse and the path of a directory containing bindings.
"""
import os
import re
import sys
import yaml
from dtlib import DT, DTError, to_num, to_nums, TYPE_EMPTY
# NOTE: testedtlib.py is the test suite for this library. It can be run
# directly.
# Implementation notes
# --------------------
#
# A '_' prefix on an identifier in Python is a convention for marking it private.
# Please do not access private things. Instead, think of what API you need, and
# add it.
#
# This library is layered on top of dtlib, and is not meant to expose it to
# clients. This keeps the header generation script simple.
#
# General biased advice:
#
# - Consider using @property for APIs that don't need parameters. It makes
# functions look like attributes, which is less awkward in clients, and makes
# it easy to switch back and forth between variables and functions.
#
# - Think about the data type of the thing you're exposing. Exposing something
# as e.g. a list or a dictionary is often nicer and more flexible than adding
# a function.
#
# - Avoid get_*() prefixes on functions. Name them after the thing they return
# instead. This often makes the code read more naturally in callers.
#
# Also, consider using @property instead of get_*().
#
# - Don't expose dtlib stuff directly.
#
# - Add documentation for any new APIs you add.
#
# The convention here is that docstrings (quoted strings) are used for public
# APIs, and "doc comments" for internal functions.
#
# @properties are documented in the class docstring, as if they were
# variables. See the existing @properties for a template.
#
# - Please use ""-quoted strings instead of ''-quoted strings, just to make
# things consistent (''-quoting is more common otherwise in Python)
#
# Public classes
#
class EDT:
"""
Represents a "high-level" view of a device tree, with a list of devices
that each have some number of registers, etc.
These attributes are available on EDT objects:
devices:
A list of Device objects for the devices
dts_path:
The .dts path passed to __init__()
bindings_dirs:
The bindings directory paths passed to __init__()
"""
def __init__(self, dts, bindings_dirs):
"""
EDT constructor. This is the top-level entry point to the library.
dts:
Path to device tree .dts file
bindings_dirs:
List of paths to directories containing bindings, in YAML format.
These directories are recursively searched for .yaml files.
"""
self.dts_path = dts
self.bindings_dirs = bindings_dirs
self._dt = DT(dts)
_check_dt(self._dt)
self._init_compat2binding(bindings_dirs)
self._init_devices()
def get_dev(self, path):
"""
Returns the Device at the DT path or alias 'path'. Raises EDTError if
the path or alias doesn't exist.
"""
try:
return self._node2dev[self._dt.get_node(path)]
except DTError as e:
_err(e)
def chosen_dev(self, name):
"""
Returns the Device pointed at by the property named 'name' in /chosen,
or None if the property is missing
"""
try:
chosen = self._dt.get_node("/chosen")
except DTError:
# No /chosen node
return None
if name not in chosen.props:
return None
# to_path() checks that the node exists
return self._node2dev[chosen.props[name].to_path()]
def _init_compat2binding(self, bindings_dirs):
# Creates self._compat2binding. This is a dictionary that maps
# (<compatible>, <bus>) tuples (both strings) to (<binding>, <path>)
# tuples. <binding> is the binding in parsed PyYAML format, and <path>
# the path to the binding (nice for binding-related error messages).
#
# For example, self._compat2binding["company,dev", "can"] contains the
# binding/path for the 'company,dev' device, when it appears on the CAN
# bus.
#
# For bindings that don't specify a bus, <bus> is None, so that e.g.
# self._compat2binding["company,notonbus", None] contains the binding.
#
# Only bindings for 'compatible' strings that appear in the device tree
# are loaded.
dt_compats = _dt_compats(self._dt)
self._binding_paths = _binding_paths(bindings_dirs)
# Add '!include foo.yaml' handling.
#
# Do yaml.Loader.add_constructor() instead of yaml.add_constructor() to be
# compatible with both version 3.13 and version 5.1 of PyYAML.
#
# TODO: Is there some 3.13/5.1-compatible way to only do this once, even
# if multiple EDT objects are created?
yaml.Loader.add_constructor("!include", self._binding_include)
self._compat2binding = {}
for binding_path in self._binding_paths:
compat = _binding_compat(binding_path)
if compat in dt_compats:
binding = _load_binding(binding_path)
self._compat2binding[compat, _binding_bus(binding)] = \
(binding, binding_path)
def _binding_include(self, loader, node):
# Implements !include. Returns a list with the YAML structures for the
# included files (a single-element list if the !include is for a single
# file).
if isinstance(node, yaml.ScalarNode):
# !include foo.yaml
return [self._binding_include_file(loader.construct_scalar(node))]
if isinstance(node, yaml.SequenceNode):
# !include [foo.yaml, bar.yaml]
return [self._binding_include_file(filename)
for filename in loader.construct_sequence(node)]
_binding_inc_error("unrecognised node type in !include statement")
def _binding_include_file(self, filename):
# _binding_include() helper for loading an !include'd file. !include
# takes just the basename of the file, so we need to make sure there
# aren't multiple candidates.
paths = [path for path in self._binding_paths
if os.path.basename(path) == filename]
if not paths:
_binding_inc_error("'{}' not found".format(filename))
if len(paths) > 1:
_binding_inc_error("multiple candidates for '{}' in !include: {}"
.format(filename, ", ".join(paths)))
with open(paths[0], encoding="utf-8") as f:
return yaml.load(f, Loader=yaml.Loader)
def _init_devices(self):
# Creates a list of devices (Device objects) from the DT nodes, in
# self.devices
# Maps dtlib.Node's to their corresponding Devices
self._node2dev = {}
self.devices = []
for node in self._dt.node_iter():
# Warning: We depend on parent Devices being created before their
# children. This is guaranteed by node_iter().
dev = Device()
dev.edt = self
dev._node = node
dev._init_binding()
dev._init_regs()
dev._set_instance_no()
self.devices.append(dev)
self._node2dev[node] = dev
for dev in self.devices:
# Device._init_props() depends on all Device objects having been
# created, due to 'type: phandle', so we run it separately.
# Property.val is set to the pointed-to Device instance for
# phandles, which must exist.
dev._init_props()
for dev in self.devices:
# These also depend on all Device objects having been created, and
# might also depend on all Device.props having been initialized
# (_init_clocks() does as of writing).
dev._init_interrupts()
dev._init_gpios()
dev._init_pwms()
dev._init_iochannels()
dev._init_clocks()
def __repr__(self):
return "<EDT for '{}', binding directories '{}'>".format(
self.dts_path, self.bindings_dirs)
class Device:
"""
Represents a device. There's a one-to-one correspondence between device
tree nodes and Devices.
These attributes are available on Device objects:
edt:
The EDT instance this device is from
name:
The name of the device. This is fetched from the node name.
unit_addr:
An integer with the ...@<unit-address> portion of the node name,
translated through any 'ranges' properties on parent nodes, or None if
the node name has no unit-address portion
path:
The device tree path of the device
label:
The text from the 'label' property on the DT node of the Device, or None
if the node has no 'label'
parent:
The parent Device, or None if there is no parent
enabled:
True unless the device's node has 'status = "disabled"'
read_only:
True if the DT node of the Device has a 'read-only' property, and False
otherwise
instance_no:
Dictionary that maps each 'compatible' string for the device to a unique
index among all devices that have that 'compatible' string.
As an example, 'instance_no["foo,led"] == 3' can be read as "this is the
fourth foo,led device".
Only enabled devices (status != "disabled") are counted. 'instance_no' is
meaningless for disabled devices.
matching_compat:
The 'compatible' string for the binding that matched the device, or
None if the device has no binding
description:
The description string from the binding file for the device, or None if
the device has no binding. Trailing whitespace (including newlines) is
removed.
binding_path:
The path to the binding file for the device, or None if the device has no
binding
compats:
A list of 'compatible' strings for the device, in the same order that
they're listed in the .dts file
regs:
A list of Register objects for the device's registers
props:
A dictionary that maps property names to Property objects. Property
objects are created for all DT properties on the device that are
mentioned in 'properties:' in the binding.
aliases:
A list of aliases for the device. This is fetched from the /aliases node.
interrupts:
A list of Interrupt objects for the interrupts generated by the device
gpios:
A dictionary that maps the <prefix> part in '<prefix>-gpios' properties
to a list of GPIO objects (see the GPIO class).
For example, 'foo-gpios = <&gpio1 1 2 &gpio2 3 4>' makes gpios["foo"] a
list of two GPIO objects.
pwms:
A list of PWM objects, derived from the 'pwms' property. The list is
empty if the device has no 'pwms' property.
iochannels:
A list of IOChannel objects, derived from the 'io-channels'
property. The list is empty if the device has no 'io-channels'
property.
clocks:
A list of Clock objects, derived from the 'clocks' property. The list is
empty if the device has no 'clocks' property.
bus:
The bus for the device as specified in its binding, e.g. "i2c" or "spi".
None if the binding doesn't specify a bus.
flash_controller:
The flash controller for the device. Only meaningful for devices
representing flash partitions.
"""
@property
def name(self):
"See the class docstring"
return self._node.name
@property
def unit_addr(self):
"See the class docstring"
# TODO: Return a plain string here later, like dtlib.Node.unit_addr?
if "@" not in self.name:
return None
try:
addr = int(self.name.split("@", 1)[1], 16)
except ValueError:
_err("{!r} has non-hex unit address".format(self))
addr = _translate(addr, self._node)
if self.regs and self.regs[0].addr != addr:
_warn("unit-address and first reg (0x{:x}) don't match for {}"
.format(self.regs[0].addr, self.name))
return addr
@property
def path(self):
"See the class docstring"
return self._node.path
@property
def label(self):
"See the class docstring"
if "label" in self._node.props:
return self._node.props["label"].to_string()
return None
@property
def parent(self):
"See the class docstring"
return self.edt._node2dev.get(self._node.parent)
@property
def enabled(self):
"See the class docstring"
return "status" not in self._node.props or \
self._node.props["status"].to_string() != "disabled"
@property
def read_only(self):
"See the class docstring"
return "read-only" in self._node.props
@property
def aliases(self):
"See the class docstring"
return [alias for alias, node in self._node.dt.alias2node.items()
if node is self._node]
@property
def bus(self):
"See the class docstring"
return _binding_bus(self._binding)
@property
def flash_controller(self):
"See the class docstring"
# The node path might be something like
# /flash-controller@4001E000/flash@0/partitions/partition@fc000. We go
# up two levels to get the flash and check its compat. The flash
# controller might be the flash itself (for cases like NOR flashes).
# For the case of 'soc-nv-flash', we assume the controller is the
# parent of the flash node.
if not self.parent or not self.parent.parent:
_err("flash partition {!r} lacks parent or grandparent node"
.format(self))
controller = self.parent.parent
if controller.matching_compat == "soc-nv-flash":
return controller.parent
return controller
def __repr__(self):
return "<Device {} in '{}', {}>".format(
self.path, self.edt.dts_path,
"binding " + self.binding_path if self.binding_path
else "no binding")
def _init_binding(self):
# Initializes Device.matching_compat, Device._binding, and
# Device.binding_path.
#
# Device._binding holds the data from the device's binding file, in the
# format returned by PyYAML (plain Python lists, dicts, etc.), or None
# if the device has no binding.
# This relies on the parent of the Device having already been
# initialized, which is guaranteed by going through the nodes in
# node_iter() order.
if "compatible" in self._node.props:
self.compats = self._node.props["compatible"].to_strings()
bus = self._bus_from_parent_binding()
for compat in self.compats:
if (compat, bus) in self.edt._compat2binding:
# Binding found
self.matching_compat = compat
self._binding, self.binding_path = \
self.edt._compat2binding[compat, bus]
self.description = self._binding.get("description")
if self.description:
self.description = self.description.rstrip()
return
else:
# No 'compatible' property. See if the parent has a 'sub-node:' key
# that gives the binding.
self.compats = []
if self.parent and self.parent._binding and \
"sub-node" in self.parent._binding:
# Binding found
self._binding = self.parent._binding["sub-node"]
self.binding_path = self.parent.binding_path
self.description = self.parent._binding.get("description")
if self.description:
self.description = self.description.rstrip()
self.matching_compat = self.parent.matching_compat
return
# No binding found
self.matching_compat = self._binding = self.binding_path = \
self.description = None
def _bus_from_parent_binding(self):
# _init_binding() helper. Returns the bus specified by
# 'child: bus: ...' in the parent binding, or None if missing.
if not self.parent:
return None
binding = self.parent._binding
if binding and "child" in binding:
return binding["child"].get("bus")
return None
def _init_props(self):
# Creates self.props. See the class docstring.
self.props = {}
if not self._binding or "properties" not in self._binding:
return
for name, options in self._binding["properties"].items():
self._init_prop(name, options)
def _init_prop(self, name, options):
# _init_props() helper for initializing a single property
prop_type = options.get("type")
if not prop_type:
_err("'{}' in {} lacks 'type'".format(name, self.binding_path))
# "Dummy" type for properties like '...-gpios', so that we can require
# all entries in 'properties:' to have a 'type: ...'. It might make
# sense to have gpios in 'properties:' for other reasons, e.g. to set
# 'category: required'.
if prop_type == "compound":
return
val = self._prop_val(name, prop_type,
options.get("category") == "optional")
if val is None:
# 'category: optional' property that wasn't there
return
# Skip properties that start with '#', like '#size-cells', and mapping
# properties like 'gpio-map'/'interrupt-map'
if name[0] == "#" or name.endswith("-map"):
return
prop = Property()
prop.dev = self
prop.name = name
prop.description = options.get("description")
if prop.description:
prop.description = prop.description.rstrip()
prop.val = val
enum = options.get("enum")
if enum is None:
prop.enum_index = None
else:
if val not in enum:
_err("value ({}) for property ({}) is not in enumerated "
"list {} for node {}".format(val, name, enum, self.name))
prop.enum_index = enum.index(val)
self.props[name] = prop
def _prop_val(self, name, prop_type, optional):
# _init_prop() helper for getting the property's value
node = self._node
prop = node.props.get(name)
if prop_type == "boolean":
if not prop:
return False
if prop.type is not TYPE_EMPTY:
_err("'{0}' in {1!r} is defined with 'type: boolean' in {2}, "
"but is assigned a value ('{3}') instead of being empty "
"('{0};')".format(name, node, self.binding_path, prop))
return True
if not prop:
if not optional and self.enabled:
_err("'{}' is marked as required in 'properties:' in {}, but "
"does not appear in {!r}".format(
name, self.binding_path, node))
return None
if prop_type == "int":
return prop.to_num()
if prop_type == "array":
return prop.to_nums()
if prop_type == "uint8-array":
return prop.to_bytes()
if prop_type == "string":
return prop.to_string()
if prop_type == "string-array":
return prop.to_strings()
if prop_type == "phandle":
return self.edt._node2dev[prop.to_node()]
_err("'{}' in 'properties:' in {} has unknown type '{}'"
.format(name, self.binding_path, prop_type))
def _init_regs(self):
# Initializes self.regs
node = self._node
self.regs = []
if "reg" not in node.props:
return
address_cells = _address_cells(node)
size_cells = _size_cells(node)
for raw_reg in _slice(node, "reg", 4*(address_cells + size_cells)):
reg = Register()
reg.dev = self
reg.addr = _translate(to_num(raw_reg[:4*address_cells]), node)
reg.size = to_num(raw_reg[4*address_cells:])
if size_cells != 0 and reg.size == 0:
_err("zero-sized 'reg' in {!r} seems meaningless (maybe you "
"want a size of one or #size-cells = 0 instead)"
.format(self._node))
self.regs.append(reg)
_add_names(node, "reg", self.regs)
def _init_interrupts(self):
# Initializes self.interrupts
node = self._node
self.interrupts = []
for controller_node, spec in _interrupts(node):
interrupt = Interrupt()
interrupt.dev = self
interrupt.controller = self.edt._node2dev[controller_node]
interrupt.specifier = self._named_cells(interrupt.controller, spec,
"interrupt")
self.interrupts.append(interrupt)
_add_names(node, "interrupt", self.interrupts)
def _init_gpios(self):
# Initializes self.gpios
self.gpios = {}
for prefix, gpios in _gpios(self._node).items():
self.gpios[prefix] = []
for controller_node, spec in gpios:
gpio = GPIO()
gpio.dev = self
gpio.controller = self.edt._node2dev[controller_node]
gpio.specifier = self._named_cells(gpio.controller, spec,
"GPIO")
gpio.name = prefix
self.gpios[prefix].append(gpio)
def _init_clocks(self):
# Initializes self.clocks
self.clocks = self._simple_phandle_val_list("clock", Clock)
# Initialize Clock.frequency
for clock in self.clocks:
controller = clock.controller
if "fixed-clock" in controller.compats:
if "clock-frequency" not in controller.props:
_err("{!r} is a 'fixed-clock', but either lacks a "
"'clock-frequency' property or does not have "
"it specified in its binding".format(controller))
clock.frequency = controller.props["clock-frequency"].val
else:
clock.frequency = None
def _init_pwms(self):
# Initializes self.pwms
self.pwms = self._simple_phandle_val_list("pwm", PWM)
def _init_iochannels(self):
# Initializes self.iochannels
self.iochannels = self._simple_phandle_val_list("io-channel", IOChannel)
def _simple_phandle_val_list(self, name, cls):
# Helper for parsing properties like
#
# <name>s = <phandle value phandle value ...>
# (e.g., gpios = <&foo 1 2 &bar 3 4>)
#
# , where each phandle points to a node that has a
#
# #<name>-cells = <size>
#
# property that gives the number of cells in the value after the
# phandle. Also parses any
#
# <name>-names = "...", "...", ...
#
# Arguments:
#
# name:
# The <name>, e.g. "clock" or "pwm". Note: no -s in the argument.
#
# cls:
# A class object. Instances of this class will be created and the
# 'dev', 'controller', 'specifier', and 'name' fields initialized.
# See the documentation for e.g. the PWM class.
#
# Returns a list of 'cls' instances.
prop = self._node.props.get(name + "s")
if not prop:
return []
res = []
for controller_node, spec in _phandle_val_list(prop, name):
obj = cls()
obj.dev = self
obj.controller = self.edt._node2dev[controller_node]
obj.specifier = self._named_cells(obj.controller, spec, name)
res.append(obj)
_add_names(self._node, name, res)
return res
def _named_cells(self, controller, spec, controller_s):
# _init_{interrupts,gpios}() helper. Returns a dictionary that maps
# #cell names given in the binding for 'controller' to cell values.
# 'spec' is the raw interrupt/GPIO data, and 'controller_s' a string
# that gives the context (for error messages).
if not controller._binding:
_err("{} controller {!r} for {!r} lacks binding"
.format(controller_s, controller._node, self._node))
if "#cells" in controller._binding:
cell_names = controller._binding["#cells"]
if not isinstance(cell_names, list):
_err("binding for {} controller {!r} has malformed #cells array"
.format(controller_s, controller._node))
else:
# Treat no #cells in the binding the same as an empty #cells, so
# that bindings don't have to have an empty #cells for e.g.
# '#clock-cells = <0>'.
cell_names = []
spec_list = to_nums(spec)
if len(spec_list) != len(cell_names):
_err("unexpected #cells length in binding for {!r} - {} instead "
"of {}".format(controller._node, len(cell_names),
len(spec_list)))
return dict(zip(cell_names, spec_list))
def _set_instance_no(self):
# Initializes self.instance_no
self.instance_no = {}
for compat in self.compats:
self.instance_no[compat] = 0
for other_dev in self.edt.devices:
if compat in other_dev.compats and other_dev.enabled:
self.instance_no[compat] += 1
class Register:
"""
Represents a register on a device.
These attributes are available on Register objects:
dev:
The Device instance this register is from
name:
The name of the register as given in the 'reg-names' property, or None if
there is no 'reg-names' property
addr:
The starting address of the register, in the parent address space. Any
'ranges' properties are taken into account.
size:
The length of the register in bytes
"""
def __repr__(self):
fields = []
if self.name is not None:
fields.append("name: " + self.name)
fields.append("addr: " + hex(self.addr))
fields.append("size: " + hex(self.size))
return "<Register, {}>".format(", ".join(fields))
class Interrupt:
"""
Represents an interrupt generated by a device.
These attributes are available on Interrupt objects:
dev:
The Device instance that generated the interrupt
name:
The name of the interrupt as given in the 'interrupt-names' property, or
None if there is no 'interrupt-names' property
controller:
The Device instance for the controller the interrupt gets sent to. Any
'interrupt-map' is taken into account, so that this is the final
controller node.
specifier:
A dictionary that maps names from the #cells portion of the binding to
cell values in the interrupt specifier. 'interrupts = <1 2>' might give
{"irq": 1, "level": 2}, for example.
"""
def __repr__(self):
fields = []
if self.name is not None:
fields.append("name: " + self.name)
fields.append("target: {}".format(self.controller))
fields.append("specifier: {}".format(self.specifier))
return "<Interrupt, {}>".format(", ".join(fields))
class GPIO:
"""
Represents a GPIO used by a device.
These attributes are available on GPIO objects:
dev:
The Device instance that uses the GPIO
name:
The name of the gpio as extracted out of the "<NAME>-gpios" property. If
the property is just "gpios" than there is no name.
controller:
The Device instance for the controller of the GPIO
specifier:
A dictionary that maps names from the #cells portion of the binding to
cell values in the gpio specifier. 'foo-gpios = <&gpioc 5 0>' might give
{"pin": 5, "flags": 0}, for example.
"""
def __repr__(self):
fields = []
if self.name is not None:
fields.append("name: " + self.name)
fields.append("target: {}".format(self.controller))
fields.append("specifier: {}".format(self.specifier))
return "<GPIO, {}>".format(", ".join(fields))
class Clock:
"""
Represents a clock used by a device.
These attributes are available on Clock objects:
dev:
The Device instance that uses the clock
name:
The name of the clock as given in the 'clock-names' property, or
None if there is no 'clock-names' property
controller:
The Device instance for the controller of the clock.
frequency:
The frequency of the clock for fixed clocks ('fixed-clock' in
'compatible'), as an integer. Derived from the 'clock-frequency'
property. None if the clock is not a fixed clock.
specifier:
A dictionary that maps names from the #cells portion of the binding to
cell values in the clock specifier
"""
def __repr__(self):
fields = []
if self.name is not None:
fields.append("name: " + self.name)
if self.frequency is not None:
fields.append("frequency: {}".format(self.frequency))
fields.append("target: {}".format(self.controller))
fields.append("specifier: {}".format(self.specifier))
return "<Clock, {}>".format(", ".join(fields))
class PWM:
"""
Represents a PWM used by a device.
These attributes are available on PWM objects:
dev:
The Device instance that uses the PWM
name:
The name of the pwm as given in the 'pwm-names' property, or the
node name if the 'pwm-names' property doesn't exist.
controller:
The Device instance for the controller of the PWM
specifier:
A dictionary that maps names from the #cells portion of the binding to
cell values in the pwm specifier. 'pwms = <&pwm 0 5000000>' might give
{"channel": 0, "period": 5000000}, for example.
"""
def __repr__(self):
fields = []
if self.name is not None:
fields.append("name: " + self.name)
fields.append("target: {}".format(self.controller))
fields.append("specifier: {}".format(self.specifier))
return "<PWM, {}>".format(", ".join(fields))
class IOChannel:
"""
Represents an IO channel used by a device, similar to the property used
by the Linux IIO bindings and described at:
https://www.kernel.org/doc/Documentation/devicetree/bindings/iio/iio-bindings.txt
These attributes are available on IO channel objects:
dev:
The Device instance that uses the IO channel
name:
The name of the IO channel as given in the 'io-channel-names' property,
or the node name if the 'io-channel-names' property doesn't exist.
controller:
The Device instance for the controller of the IO channel
specifier:
A dictionary that maps names from the #cells portion of the binding to
cell values in the io-channel specifier. 'io-channels = <&adc 3>' might
give {"input": 3}, for example.
"""
def __repr__(self):
fields = []
if self.name is not None:
fields.append("name: " + self.name)
fields.append("target: {}".format(self.controller))
fields.append("specifier: {}".format(self.specifier))
return "<IOChannel, {}>".format(", ".join(fields))
class Property:
"""
Represents a property on a Device, as set in its DT node and with
additional info from the 'properties:' section of the binding.
Only properties mentioned in 'properties:' get created.
These attributes are available on Property objects:
dev:
The Device instance the property is on
name:
The name of the property
description:
The description string from the property as given in the binding, or None
if missing. Trailing whitespace (including newlines) is removed.
val:
The value of the property, with the format determined by the 'type:' key
from the binding. For 'type: phandle' properties, this is the pointed-to
Device instance.
enum_index:
The index of the property's value in the 'enum:' list in the binding, or
None if the binding has no 'enum:'
"""
def __repr__(self):
fields = ["name: " + self.name,
# repr() to deal with lists
"value: " + repr(self.val)]
if self.enum_index is not None:
fields.append("enum index: {}".format(self.enum_index))
return "<Property, {}>".format(", ".join(fields))
class EDTError(Exception):
"Exception raised for Extended Device Tree-related errors"
#
# Public global functions
#
def spi_dev_cs_gpio(dev):
# Returns an SPI device's GPIO chip select if it exists, as a GPIO
# instance, and None otherwise. See
# Documentation/devicetree/bindings/spi/spi-bus.txt in the Linux kernel.
if dev.bus == "spi" and dev.parent:
parent_cs = dev.parent.gpios.get("cs")
if parent_cs:
# cs-gpios is indexed by the unit address
cs_index = dev.regs[0].addr
if cs_index >= len(parent_cs):
_err("index from 'regs' in {!r} ({}) is >= number of cs-gpios "
"in {!r} ({})".format(
dev, cs_index, dev.parent, len(parent_cs)))
return parent_cs[cs_index]
return None
#
# Private global functions
#
def _dt_compats(dt):
# Returns a set() with all 'compatible' strings in the device tree
# represented by dt (a dtlib.DT instance)
return {compat
for node in dt.node_iter()
if "compatible" in node.props
for compat in node.props["compatible"].to_strings()}
def _binding_paths(bindings_dirs):
# Returns a list with the paths to all bindings (.yaml files) in
# 'bindings_dirs'
binding_paths = []
for bindings_dir in bindings_dirs:
for root, _, filenames in os.walk(bindings_dir):
for filename in filenames:
if filename.endswith(".yaml"):
binding_paths.append(os.path.join(root, filename))
return binding_paths
def _binding_compat(binding_path):
# Returns the compatible string specified in the binding at 'binding_path'.
# Uses a regex to avoid having to parse the bindings, which is slow when
# done for all bindings.
with open(binding_path, encoding="utf-8") as binding:
for line in binding:
match = re.match(r'\s+constraint:\s*"([^"]*)"', line)
if match:
return match.group(1)
return None
def _binding_bus(binding):
# Returns the bus specified in 'binding' (the bus the device described by
# 'binding' is on), e.g. "i2c", or None if 'binding' is None or doesn't
# specify a bus
if binding and "parent" in binding:
return binding["parent"].get("bus")
return None
def _binding_inc_error(msg):
# Helper for reporting errors in the !include implementation
raise yaml.constructor.ConstructorError(None, None, "error: " + msg)
def _load_binding(path):
# Loads a top-level binding .yaml file from 'path', also handling any
# !include'd files. Returns the parsed PyYAML output (Python
# lists/dictionaries/strings/etc. representing the file).
with open(path, encoding="utf-8") as f:
return _merge_included_bindings(yaml.load(f, Loader=yaml.Loader), path)
def _merge_included_bindings(binding, binding_path):
# Merges any bindings in the 'inherits:' section of 'binding' into the top
# level of 'binding'. !includes have already been processed at this point,
# and leave the data for the included binding(s) in 'inherits:'.
#
# Properties in 'binding' take precedence over properties from included
# bindings.
# Currently, we require that each !include'd file is a well-formed
# binding in itself
_check_binding(binding, binding_path)
if "inherits" in binding:
for inherited in binding.pop("inherits"):
_merge_props(
binding, _merge_included_bindings(inherited, binding_path),
None, binding_path)
return binding
def _merge_props(to_dict, from_dict, parent, binding_path):
# Recursively merges 'from_dict' into 'to_dict', to implement !include. If
# a key exists in both 'from_dict' and 'to_dict', then the value in
# 'to_dict' takes precedence.
#
# 'parent' is the name of the parent key containing 'to_dict' and
# 'from_dict', and 'binding_path' is the path to the top-level binding.
# These are used to generate errors for sketchy property overwrites.
for prop in from_dict:
if isinstance(to_dict.get(prop), dict) and \
isinstance(from_dict[prop], dict):
_merge_props(to_dict[prop], from_dict[prop], prop, binding_path)
elif prop not in to_dict:
to_dict[prop] = from_dict[prop]
elif _bad_overwrite(to_dict, from_dict, prop):
_err("{} (in '{}'): '{}' from !included file overwritten "
"('{}' replaced with '{}')".format(
binding_path, parent, prop, from_dict[prop],
to_dict[prop]))
def _bad_overwrite(to_dict, from_dict, prop):
# _merge_props() helper. Returns True in cases where it's bad that
# to_dict[prop] takes precedence over from_dict[prop].
# These are overridden deliberately
if prop in {"title", "description"}:
return False
if to_dict[prop] == from_dict[prop]:
return False
# Allow a property to be made required when it previously was optional
# without a warning
if prop == "category" and to_dict["category"] == "required" and \
from_dict["category"] == "optional":
return False
return True
def _check_binding(binding, binding_path):
# Does sanity checking on 'binding'
for prop in "title", "description":
if prop not in binding:
_err("missing '{}' property in {}".format(prop, binding_path))
for prop in "title", "description":
if not isinstance(binding[prop], str) or not binding[prop]:
_err("missing, malformed, or empty '{}' in {}"
.format(prop, binding_path))
ok_top = {"title", "description", "inherits", "properties", "#cells",
"parent", "child", "sub-node"}
for prop in binding:
if prop not in ok_top:
_err("unknown key '{}' in {}, expected one of {}"
.format(prop, binding_path, ", ".join(ok_top)))
for pc in "parent", "child":
if pc in binding:
# Just 'bus:' is expected at the moment
if binding[pc].keys() != {"bus"}:
_err("expected (just) 'bus:' in '{}:' in {}"
.format(pc, binding_path))
if not isinstance(binding[pc]["bus"], str):
_err("malformed '{}: bus:' value in {}, expected string"
.format(pc, binding_path))
# Check properties
if "properties" not in binding:
return
ok_prop_keys = {"description", "type", "category", "constraint", "enum"}
ok_categories = {"required", "optional"}
for prop_name, options in binding["properties"].items():
for key in options:
if key not in ok_prop_keys:
_err("unknown setting '{}' in 'properties: {}: ...' in {}, "
"expected one of {}".format(
key, prop_name, binding_path,
", ".join(ok_prop_keys)))
if "category" in options and options["category"] not in ok_categories:
_err("unrecognized category '{}' for '{}' in 'properties' in {}, "
"expected one of {}".format(
options["category"], prop_name, binding_path,
", ".join(ok_categories)))
if "description" in options and \
not isinstance(options["description"], str):
_err("missing, malformed, or empty 'description' for '{}' in "
"'properties' in {}".format(prop_name, binding_path))
def _translate(addr, node):
# Recursively translates 'addr' on 'node' to the address space(s) of its
# parent(s), by looking at 'ranges' properties. Returns the translated
# address.
if not node.parent or "ranges" not in node.parent.props:
# No translation
return addr
if not node.parent.props["ranges"].value:
# DT spec.: "If the property is defined with an <empty> value, it
# specifies that the parent and child address space is identical, and
# no address translation is required."
#
# Treat this the same as a 'range' that explicitly does a one-to-one
# mapping, as opposed to there not being any translation.
return _translate(addr, node.parent)
# Gives the size of each component in a translation 3-tuple in 'ranges'
child_address_cells = _address_cells(node)
parent_address_cells = _address_cells(node.parent)
child_size_cells = _size_cells(node)
# Number of cells for one translation 3-tuple in 'ranges'
entry_cells = child_address_cells + parent_address_cells + child_size_cells
for raw_range in _slice(node.parent, "ranges", 4*entry_cells):
child_addr = to_num(raw_range[:4*child_address_cells])
raw_range = raw_range[4*child_address_cells:]
parent_addr = to_num(raw_range[:4*parent_address_cells])
raw_range = raw_range[4*parent_address_cells:]
child_len = to_num(raw_range)
if child_addr <= addr < child_addr + child_len:
# 'addr' is within range of a translation in 'ranges'. Recursively
# translate it and return the result.
return _translate(parent_addr + addr - child_addr, node.parent)
# 'addr' is not within range of any translation in 'ranges'
return addr
def _add_names(node, names_ident, objs):
# Helper for registering names from <foo>-names properties.
#
# node:
# Device tree node
#
# names-ident:
# The <foo> part of <foo>-names, e.g. "reg" for "reg-names"
#
# objs:
# list of objects whose .name field should be set
full_names_ident = names_ident + "-names"
if full_names_ident in node.props:
names = node.props[full_names_ident].to_strings()
if len(names) != len(objs):
_err("{} property in {} has {} strings, expected {} strings"
.format(full_names_ident, node.name, len(names), len(objs)))
for obj, name in zip(objs, names):
obj.name = name
else:
for obj in objs:
obj.name = None
def _interrupt_parent(node):
# Returns the node pointed at by the closest 'interrupt-parent', searching
# the parents of 'node'. As of writing, this behavior isn't specified in
# the DT spec., but seems to match what some .dts files except.
while node:
if "interrupt-parent" in node.props:
return node.props["interrupt-parent"].to_node()
node = node.parent
_err("{!r} has an 'interrupts' property, but neither the node nor any "
"of its parents has an 'interrupt-parent' property".format(node))
def _interrupts(node):
# Returns a list of (<controller>, <specifier>) tuples, with one tuple per
# interrupt generated by 'node'. <controller> is the destination of the
# interrupt (possibly after mapping through an 'interrupt-map'), and
# <specifier> the data associated with the interrupt (as a 'bytes' object).
# Takes precedence over 'interrupts' if both are present
if "interrupts-extended" in node.props:
prop = node.props["interrupts-extended"]
return [_map_interrupt(node, iparent, spec)
for iparent, spec in _phandle_val_list(prop, "interrupt")]
if "interrupts" in node.props:
# Treat 'interrupts' as a special case of 'interrupts-extended', with
# the same interrupt parent for all interrupts
iparent = _interrupt_parent(node)
interrupt_cells = _interrupt_cells(iparent)
return [_map_interrupt(node, iparent, raw)
for raw in _slice(node, "interrupts", 4*interrupt_cells)]
return []
def _map_interrupt(child, parent, child_spec):
# Translates an interrupt headed from 'child' to 'parent' with specifier
# 'child_spec' through any 'interrupt-map' properties. Returns a
# (<controller>, <specifier>) tuple with the final destination after
# mapping.
if "interrupt-controller" in parent.props:
return (parent, child_spec)
def own_address_cells(node):
# Used for parents pointed at by 'interrupt-map'. We can't use
# _address_cells(), because it's the #address-cells property on 'node'
# itself that matters.
address_cells = node.props.get("#address-cells")
if not address_cells:
_err("missing #address-cells on {!r} (while handling interrupt-map)"
.format(node))
return address_cells.to_num()
def spec_len_fn(node):
# Can't use _address_cells() here, because it's the #address-cells
# property on 'node' itself that matters
return 4*(own_address_cells(node) + _interrupt_cells(node))
parent, raw_spec = _map(
"interrupt", child, parent, _raw_unit_addr(child) + child_spec,
spec_len_fn)
# Strip the parent unit address part, if any
return (parent, raw_spec[4*own_address_cells(parent):])
def _gpios(node):
# Returns a dictionary that maps '<prefix>-gpios' prefixes to lists of
# (<controller>, <specifier>) tuples (possibly after mapping through an
# gpio-map). <controller> is a dtlib.Node.
res = {}
for name, prop in node.props.items():
if name.endswith("-gpios") or name == "gpios":
# Get the prefix from the property name:
# - gpios -> "" (deprecated, should have a prefix)
# - foo-gpios -> "foo"
# - etc.
prefix = name[:-5]
if prefix.endswith("-"):
prefix = prefix[:-1]
res[prefix] = [
_map_gpio(prop.node, controller, spec)
for controller, spec in _phandle_val_list(prop, "gpio")
]
return res
def _map_gpio(child, parent, child_spec):
# Returns a (<controller>, <specifier>) tuple with the final destination
# after mapping through any 'gpio-map' properties. See _map_interrupt().
if "gpio-map" not in parent.props:
return (parent, child_spec)
return _map("gpio", child, parent, child_spec,
lambda node: 4*_gpio_cells(node))
def _map(prefix, child, parent, child_spec, spec_len_fn):
# Common code for mapping through <prefix>-map properties, e.g.
# interrupt-map and gpio-map.
#
# prefix:
# The prefix, e.g. "interrupt" or "gpio"
#
# child:
# The "sender", e.g. the node with 'interrupts = <...>'
#
# parent:
# The "receiver", e.g. a node with 'interrupt-map = <...>' or
# 'interrupt-controller' (no mapping)
#
# child_spec:
# The data associated with the interrupt/GPIO/etc., as a 'bytes' object,
# e.g. <1 2> for 'foo-gpios = <&gpio1 1 2>'.
#
# spec_len_fn:
# Function called on a parent specified in a *-map property to get its
# *-cells value, e.g. #interrupt-cells
map_prop = parent.props.get(prefix + "-map")
if not map_prop:
if prefix + "-controller" not in parent.props:
_err("expected '{}-controller' property on {!r} "
"(referenced by {!r})".format(prefix, parent, child))
# No mapping
return (parent, child_spec)
masked_child_spec = _mask(prefix, child, parent, child_spec)
raw = map_prop.value
while raw:
if len(raw) < len(child_spec):
_err("bad value for {!r}, missing/truncated child specifier"
.format(map_prop))
child_spec_entry = raw[:len(child_spec)]
raw = raw[len(child_spec):]
if len(raw) < 4:
_err("bad value for {!r}, missing/truncated phandle"
.format(map_prop))
phandle = to_num(raw[:4])
raw = raw[4:]
# Parent specified in *-map
map_parent = parent.dt.phandle2node.get(phandle)
if not map_parent:
_err("bad phandle in " + repr(map_prop))
map_parent_spec_len = spec_len_fn(map_parent)
if len(raw) < map_parent_spec_len:
_err("bad value for {!r}, missing/truncated parent specifier"
.format(map_prop))
parent_spec = raw[:map_parent_spec_len]
raw = raw[map_parent_spec_len:]
# Got one *-map row. Check if it matches the child specifier.
if child_spec_entry == masked_child_spec:
# Handle *-map-pass-thru
parent_spec = _pass_thru(
prefix, child, parent, child_spec, parent_spec)
# Found match. Recursively map and return it.
return _map(prefix, parent, map_parent, parent_spec, spec_len_fn)
_err("child specifier for {!r} ({}) does not appear in {!r}"
.format(child, child_spec, map_prop))
def _mask(prefix, child, parent, child_spec):
# Common code for handling <prefix>-mask properties, e.g. interrupt-mask.
# See _map() for the parameters.
mask_prop = parent.props.get(prefix + "-map-mask")
if not mask_prop:
# No mask
return child_spec
mask = mask_prop.value
if len(mask) != len(child_spec):
_err("{!r}: expected '{}-mask' in {!r} to be {} bytes, is {} bytes"
.format(child, prefix, parent, len(child_spec), len(mask)))
return _and(child_spec, mask)
def _pass_thru(prefix, child, parent, child_spec, parent_spec):
# Common code for handling <prefix>-map-thru properties, e.g.
# interrupt-pass-thru.
#
# parent_spec:
# The parent specifier from the matched entry in the <prefix>-map
# property
#
# See _map() for the other parameters.
pass_thru_prop = parent.props.get(prefix + "-map-pass-thru")
if not pass_thru_prop:
# No pass-thru
return parent_spec
pass_thru = pass_thru_prop.value
if len(pass_thru) != len(child_spec):
_err("{!r}: expected '{}-map-pass-thru' in {!r} to be {} bytes, is {} bytes"
.format(child, prefix, parent, len(child_spec), len(pass_thru)))
res = _or(_and(child_spec, pass_thru),
_and(parent_spec, _not(pass_thru)))
# Truncate to length of parent spec.
return res[-len(parent_spec):]
def _raw_unit_addr(node):
# _map_interrupt() helper. Returns the unit address (derived from 'reg' and
# #address-cells) as a raw 'bytes'
if 'reg' not in node.props:
_err("{!r} lacks 'reg' property (needed for 'interrupt-map' unit "
"address lookup)".format(node))
addr_len = 4*_address_cells(node)
if len(node.props['reg'].value) < addr_len:
_err("{!r} has too short 'reg' property (while doing 'interrupt-map' "
"unit address lookup)".format(node))
return node.props['reg'].value[:addr_len]
def _and(b1, b2):
# Returns the bitwise AND of the two 'bytes' objects b1 and b2. Pads
# with ones on the left if the lengths are not equal.
# Pad on the left, to equal length
maxlen = max(len(b1), len(b2))
return bytes(x & y for x, y in zip(b1.rjust(maxlen, b'\xff'),
b2.rjust(maxlen, b'\xff')))
def _or(b1, b2):
# Returns the bitwise OR of the two 'bytes' objects b1 and b2. Pads with
# zeros on the left if the lengths are not equal.
# Pad on the left, to equal length
maxlen = max(len(b1), len(b2))
return bytes(x | y for x, y in zip(b1.rjust(maxlen, b'\x00'),
b2.rjust(maxlen, b'\x00')))
def _not(b):
# Returns the bitwise not of the 'bytes' object 'b'
# ANDing with 0xFF avoids negative numbers
return bytes(~x & 0xFF for x in b)
def _phandle_val_list(prop, n_cells_name):
# Parses a '<phandle> <value> <phandle> <value> ...' value. The number of
# cells that make up each <value> is derived from the node pointed at by
# the preceding <phandle>.
#
# prop:
# dtlib.Property with value to parse
#
# n_cells_name:
# The <name> part of the #<name>-cells property to look for on the nodes
# the phandles point to, e.g. "gpio" for #gpio-cells.
#
# Returns a list of (<node>, <value>) tuples, where <node> is the node
# pointed at by <phandle>.
full_n_cells_name = "#{}-cells".format(n_cells_name)
res = []
raw = prop.value
while raw:
if len(raw) < 4:
# Not enough room for phandle
_err("bad value for " + repr(prop))
phandle = to_num(raw[:4])
raw = raw[4:]
node = prop.node.dt.phandle2node.get(phandle)
if not node:
_err("bad phandle in " + repr(prop))
if full_n_cells_name not in node.props:
_err("{!r} lacks {}".format(node, full_n_cells_name))
n_cells = node.props[full_n_cells_name].to_num()
if len(raw) < 4*n_cells:
_err("missing data after phandle in " + repr(prop))
res.append((node, raw[:4*n_cells]))
raw = raw[4*n_cells:]
return res
def _address_cells(node):
# Returns the #address-cells setting for 'node', giving the number of <u32>
# cells used to encode the address in the 'reg' property
if "#address-cells" in node.parent.props:
return node.parent.props["#address-cells"].to_num()
return 2 # Default value per DT spec.
def _size_cells(node):
# Returns the #size-cells setting for 'node', giving the number of <u32>
# cells used to encode the size in the 'reg' property
if "#size-cells" in node.parent.props:
return node.parent.props["#size-cells"].to_num()
return 1 # Default value per DT spec.
def _interrupt_cells(node):
# Returns the #interrupt-cells property value on 'node', erroring out if
# 'node' has no #interrupt-cells property
if "#interrupt-cells" not in node.props:
_err("{!r} lacks #interrupt-cells".format(node))
return node.props["#interrupt-cells"].to_num()
def _gpio_cells(node):
if "#gpio-cells" not in node.props:
_err("{!r} lacks #gpio-cells".format(node))
return node.props["#gpio-cells"].to_num()
def _slice(node, prop_name, size):
# Splits node.props[prop_name].value into 'size'-sized chunks, returning a
# list of chunks. Raises EDTError if the length of the property is not
# evenly divisible by 'size'.
raw = node.props[prop_name].value
if len(raw) % size:
_err("'{}' property in {!r} has length {}, which is not evenly "
"divisible by {}".format(prop_name, node, len(raw), size))
return [raw[i:i + size] for i in range(0, len(raw), size)]
def _check_dt(dt):
# Does devicetree sanity checks. dtlib is meant to be general and
# anything-goes except for very special properties like phandle, but in
# edtlib we can be pickier.
# Check that 'status' has one of the values given in the devicetree spec.
ok_status = {"okay", "disabled", "reserved", "fail", "fail-sss"}
for node in dt.node_iter():
if "status" in node.props:
try:
status_val = node.props["status"].to_string()
except DTError as e:
# The error message gives the path
_err(str(e))
if status_val not in ok_status:
_err("unknown 'status' value \"{}\" in {} in {}, expected one "
"of {} (see the devicetree specification)"
.format(status_val, node.path, node.dt.filename,
", ".join(ok_status)))
def _err(msg):
raise EDTError(msg)
def _warn(msg):
print("warning: " + msg, file=sys.stderr)