/*
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* pylibfdt - Flat Device Tree manipulation in Python
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* Copyright (C) 2017 Google, Inc.
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* Written by Simon Glass <sjg@chromium.org>
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*
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* SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause
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*/
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%module libfdt
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%include <stdint.i>
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%{
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#define SWIG_FILE_WITH_INIT
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#include "libfdt.h"
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%}
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%pythoncode %{
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import struct
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# Error codes, corresponding to FDT_ERR_... in libfdt.h
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(NOTFOUND,
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EXISTS,
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NOSPACE,
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BADOFFSET,
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BADPATH,
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BADPHANDLE,
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BADSTATE,
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TRUNCATED,
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BADMAGIC,
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BADVERSION,
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BADSTRUCTURE,
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BADLAYOUT,
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INTERNAL,
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BADNCELLS,
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BADVALUE,
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BADOVERLAY,
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NOPHANDLES) = QUIET_ALL = range(1, 18)
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# QUIET_ALL can be passed as the 'quiet' parameter to avoid exceptions
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# altogether. All # functions passed this value will return an error instead
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# of raising an exception.
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# Pass this as the 'quiet' parameter to return -ENOTFOUND on NOTFOUND errors,
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# instead of raising an exception.
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QUIET_NOTFOUND = (NOTFOUND,)
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class FdtException(Exception):
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"""An exception caused by an error such as one of the codes above"""
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def __init__(self, err):
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self.err = err
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def __str__(self):
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return 'pylibfdt error %d: %s' % (self.err, fdt_strerror(self.err))
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def strerror(fdt_err):
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"""Get the string for an error number
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Args:
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fdt_err: Error number (-ve)
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Returns:
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String containing the associated error
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"""
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return fdt_strerror(fdt_err)
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def check_err(val, quiet=()):
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"""Raise an error if the return value is -ve
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This is used to check for errors returned by libfdt C functions.
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Args:
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val: Return value from a libfdt function
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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val if val >= 0
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Raises
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FdtException if val < 0
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"""
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if val < 0:
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if -val not in quiet:
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raise FdtException(val)
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return val
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def check_err_null(val, quiet=()):
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"""Raise an error if the return value is NULL
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This is used to check for a NULL return value from certain libfdt C
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functions
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Args:
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val: Return value from a libfdt function
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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val if val is a list, None if not
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Raises
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FdtException if val indicates an error was reported and the error
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is not in @quiet.
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"""
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# Normally a list is returned which contains the data and its length.
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# If we get just an integer error code, it means the function failed.
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if not isinstance(val, list):
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if -val not in quiet:
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raise FdtException(val)
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return val
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class Fdt:
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"""Device tree class, supporting all operations
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The Fdt object is created is created from a device tree binary file,
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e.g. with something like:
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fdt = Fdt(open("filename.dtb").read())
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Operations can then be performed using the methods in this class. Each
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method xxx(args...) corresponds to a libfdt function fdt_xxx(fdt, args...).
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All methods raise an FdtException if an error occurs. To avoid this
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behaviour a 'quiet' parameter is provided for some functions. This
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defaults to empty, but you can pass a list of errors that you expect.
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If one of these errors occurs, the function will return an error number
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(e.g. -NOTFOUND).
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"""
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def __init__(self, data):
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self._fdt = bytearray(data)
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check_err(fdt_check_header(self._fdt));
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def subnode_offset(self, parentoffset, name, quiet=()):
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"""Get the offset of a named subnode
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Args:
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parentoffset: Offset of the parent node to check
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name: Name of the required subnode, e.g. 'subnode@1'
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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The node offset of the found node, if any
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Raises
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FdtException if there is no node with that name, or other error
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"""
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return check_err(fdt_subnode_offset(self._fdt, parentoffset, name),
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quiet)
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def path_offset(self, path, quiet=()):
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"""Get the offset for a given path
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Args:
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path: Path to the required node, e.g. '/node@3/subnode@1'
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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Node offset
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Raises
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FdtException if the path is not valid or not found
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"""
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return check_err(fdt_path_offset(self._fdt, path), quiet)
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def first_property_offset(self, nodeoffset, quiet=()):
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"""Get the offset of the first property in a node offset
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Args:
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nodeoffset: Offset to the node to check
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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Offset of the first property
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Raises
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FdtException if the associated node has no properties, or some
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other error occurred
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"""
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return check_err(fdt_first_property_offset(self._fdt, nodeoffset),
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quiet)
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def next_property_offset(self, prop_offset, quiet=()):
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"""Get the next property in a node
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Args:
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prop_offset: Offset of the previous property
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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Offset of the next property
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Raises:
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FdtException if the associated node has no more properties, or
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some other error occurred
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"""
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return check_err(fdt_next_property_offset(self._fdt, prop_offset),
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quiet)
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def get_name(self, nodeoffset):
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"""Get the name of a node
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Args:
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nodeoffset: Offset of node to check
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Returns:
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Node name
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Raises:
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FdtException on error (e.g. nodeoffset is invalid)
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"""
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return check_err_null(fdt_get_name(self._fdt, nodeoffset))[0]
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def get_property_by_offset(self, prop_offset, quiet=()):
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"""Obtains a property that can be examined
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Args:
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prop_offset: Offset of property (e.g. from first_property_offset())
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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Property object, or None if not found
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Raises:
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FdtException on error (e.g. invalid prop_offset or device
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tree format)
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"""
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pdata = check_err_null(
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fdt_get_property_by_offset(self._fdt, prop_offset), quiet)
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if isinstance(pdata, (int)):
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return pdata
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return Property(pdata[0], pdata[1])
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def first_subnode(self, nodeoffset, quiet=()):
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"""Find the first subnode of a parent node
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Args:
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nodeoffset: Node offset of parent node
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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The offset of the first subnode, if any
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Raises:
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FdtException if no subnode found or other error occurs
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"""
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return check_err(fdt_first_subnode(self._fdt, nodeoffset), quiet)
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def next_subnode(self, nodeoffset, quiet=()):
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"""Find the next subnode
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Args:
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nodeoffset: Node offset of previous subnode
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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The offset of the next subnode, if any
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Raises:
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FdtException if no more subnode found or other error occurs
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"""
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return check_err(fdt_next_subnode(self._fdt, nodeoffset), quiet)
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def totalsize(self):
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"""Return the total size of the device tree
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Returns:
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Total tree size in bytes
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"""
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return check_err(fdt_totalsize(self._fdt))
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def off_dt_struct(self):
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"""Return the start of the device tree struct area
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Returns:
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Start offset of struct area
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"""
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return check_err(fdt_off_dt_struct(self._fdt))
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def pack(self, quiet=()):
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"""Pack the device tree to remove unused space
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This adjusts the tree in place.
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Args:
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quiet: Errors to ignore (empty to raise on all errors)
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Raises:
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FdtException if any error occurs
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"""
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return check_err(fdt_pack(self._fdt), quiet)
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def delprop(self, nodeoffset, prop_name):
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"""Delete a property from a node
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Args:
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nodeoffset: Node offset containing property to delete
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prop_name: Name of property to delete
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Raises:
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FdtError if the property does not exist, or another error occurs
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"""
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return check_err(fdt_delprop(self._fdt, nodeoffset, prop_name))
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def getprop(self, nodeoffset, prop_name, quiet=()):
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"""Get a property from a node
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Args:
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nodeoffset: Node offset containing property to get
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prop_name: Name of property to get
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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Value of property as a bytearray, or -ve error number
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Raises:
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FdtError if any error occurs (e.g. the property is not found)
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"""
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pdata = check_err_null(fdt_getprop(self._fdt, nodeoffset, prop_name),
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quiet)
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if isinstance(pdata, (int)):
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return pdata
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return bytearray(pdata[0])
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def get_phandle(self, nodeoffset):
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"""Get the phandle of a node
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Args:
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nodeoffset: Node offset to check
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Returns:
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phandle of node, or 0 if the node has no phandle or another error
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occurs
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"""
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return fdt_get_phandle(self._fdt, nodeoffset)
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def parent_offset(self, nodeoffset, quiet=()):
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"""Get the offset of a node's parent
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Args:
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nodeoffset: Node offset to check
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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The offset of the parent node, if any
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Raises:
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FdtException if no parent found or other error occurs
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"""
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return check_err(fdt_parent_offset(self._fdt, nodeoffset), quiet)
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def node_offset_by_phandle(self, phandle, quiet=()):
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"""Get the offset of a node with the given phandle
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Args:
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phandle: Phandle to search for
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quiet: Errors to ignore (empty to raise on all errors)
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Returns:
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The offset of node with that phandle, if any
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Raises:
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FdtException if no node found or other error occurs
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"""
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return check_err(fdt_node_offset_by_phandle(self._fdt, phandle), quiet)
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class Property:
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"""Holds a device tree property name and value.
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This holds a copy of a property taken from the device tree. It does not
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reference the device tree, so if anything changes in the device tree,
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a Property object will remain valid.
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Properties:
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name: Property name
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value: Proper value as a bytearray
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"""
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def __init__(self, name, value):
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self.name = name
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self.value = value
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%}
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%rename(fdt_property) fdt_property_func;
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typedef int fdt32_t;
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%include "libfdt/fdt.h"
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%include "typemaps.i"
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/* Most functions don't change the device tree, so use a const void * */
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%typemap(in) (const void *)(const void *fdt) {
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if (!PyByteArray_Check($input)) {
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SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname"
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"', argument " "$argnum"" of type '" "$type""'");
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}
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$1 = (void *)PyByteArray_AsString($input);
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fdt = $1;
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fdt = fdt; /* avoid unused variable warning */
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}
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/* Some functions do change the device tree, so use void * */
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%typemap(in) (void *)(const void *fdt) {
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if (!PyByteArray_Check($input)) {
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SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname"
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"', argument " "$argnum"" of type '" "$type""'");
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}
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$1 = PyByteArray_AsString($input);
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fdt = $1;
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fdt = fdt; /* avoid unused variable warning */
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}
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%typemap(out) (struct fdt_property *) {
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PyObject *buff;
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if ($1) {
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resultobj = PyString_FromString(
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fdt_string(fdt1, fdt32_to_cpu($1->nameoff)));
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buff = PyByteArray_FromStringAndSize(
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(const char *)($1 + 1), fdt32_to_cpu($1->len));
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resultobj = SWIG_Python_AppendOutput(resultobj, buff);
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}
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}
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%apply int *OUTPUT { int *lenp };
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/* typemap used for fdt_getprop() */
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%typemap(out) (const void *) {
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if (!$1)
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$result = Py_None;
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else
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$result = Py_BuildValue("s#", $1, *arg4);
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}
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/* We have both struct fdt_property and a function fdt_property() */
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%warnfilter(302) fdt_property;
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/* These are macros in the header so have to be redefined here */
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int fdt_magic(const void *fdt);
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int fdt_totalsize(const void *fdt);
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int fdt_off_dt_struct(const void *fdt);
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int fdt_off_dt_strings(const void *fdt);
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int fdt_off_mem_rsvmap(const void *fdt);
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int fdt_version(const void *fdt);
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int fdt_last_comp_version(const void *fdt);
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int fdt_boot_cpuid_phys(const void *fdt);
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int fdt_size_dt_strings(const void *fdt);
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int fdt_size_dt_struct(const void *fdt);
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%include <../libfdt/libfdt.h>
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