u-boot/tools/binman/entry.py
Simon Glass badf0ec6e4 binman: Avoid setting sys.path globally
At present we set the Python path at the start of binman so we can read
modules in the 'etype' directory. This is a bit messy since it affects
'import' statements through binman.

Adjust the code to set the path locally, just where it is needed. Move
the 'entry' module in with the other base modules to help with this. It
makes more sense here anyway since it does not implement an entry type.

Signed-off-by: Simon Glass <sjg@chromium.org>
2018-06-07 11:25:08 -08:00

222 lines
7.8 KiB
Python

# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2016 Google, Inc
#
# Base class for all entries
#
# importlib was introduced in Python 2.7 but there was a report of it not
# working in 2.7.12, so we work around this:
# http://lists.denx.de/pipermail/u-boot/2016-October/269729.html
try:
import importlib
have_importlib = True
except:
have_importlib = False
import fdt_util
import os
import sys
import tools
modules = {}
our_path = os.path.dirname(os.path.realpath(__file__))
class Entry(object):
"""An Entry in the section
An entry corresponds to a single node in the device-tree description
of the section. Each entry ends up being a part of the final section.
Entries can be placed either right next to each other, or with padding
between them. The type of the entry determines the data that is in it.
This class is not used by itself. All entry objects are subclasses of
Entry.
Attributes:
section: The section containing this entry
node: The node that created this entry
pos: Absolute position of entry within the section, None if not known
size: Entry size in bytes, None if not known
contents_size: Size of contents in bytes, 0 by default
align: Entry start position alignment, or None
align_size: Entry size alignment, or None
align_end: Entry end position alignment, or None
pad_before: Number of pad bytes before the contents, 0 if none
pad_after: Number of pad bytes after the contents, 0 if none
data: Contents of entry (string of bytes)
"""
def __init__(self, section, etype, node, read_node=True):
self.section = section
self.etype = etype
self._node = node
self.pos = None
self.size = None
self.contents_size = 0
self.align = None
self.align_size = None
self.align_end = None
self.pad_before = 0
self.pad_after = 0
self.pos_unset = False
if read_node:
self.ReadNode()
@staticmethod
def Create(section, node, etype=None):
"""Create a new entry for a node.
Args:
section: Image object containing this node
node: Node object containing information about the entry to create
etype: Entry type to use, or None to work it out (used for tests)
Returns:
A new Entry object of the correct type (a subclass of Entry)
"""
if not etype:
etype = fdt_util.GetString(node, 'type', node.name)
# Convert something like 'u-boot@0' to 'u_boot' since we are only
# interested in the type.
module_name = etype.replace('-', '_')
if '@' in module_name:
module_name = module_name.split('@')[0]
module = modules.get(module_name)
# Also allow entry-type modules to be brought in from the etype directory.
# Import the module if we have not already done so.
if not module:
old_path = sys.path
sys.path.insert(0, os.path.join(our_path, 'etype'))
try:
if have_importlib:
module = importlib.import_module(module_name)
else:
module = __import__(module_name)
except ImportError:
raise ValueError("Unknown entry type '%s' in node '%s'" %
(etype, node.path))
finally:
sys.path = old_path
modules[module_name] = module
# Call its constructor to get the object we want.
obj = getattr(module, 'Entry_%s' % module_name)
return obj(section, etype, node)
def ReadNode(self):
"""Read entry information from the node
This reads all the fields we recognise from the node, ready for use.
"""
self.pos = fdt_util.GetInt(self._node, 'pos')
self.size = fdt_util.GetInt(self._node, 'size')
self.align = fdt_util.GetInt(self._node, 'align')
if tools.NotPowerOfTwo(self.align):
raise ValueError("Node '%s': Alignment %s must be a power of two" %
(self._node.path, self.align))
self.pad_before = fdt_util.GetInt(self._node, 'pad-before', 0)
self.pad_after = fdt_util.GetInt(self._node, 'pad-after', 0)
self.align_size = fdt_util.GetInt(self._node, 'align-size')
if tools.NotPowerOfTwo(self.align_size):
raise ValueError("Node '%s': Alignment size %s must be a power "
"of two" % (self._node.path, self.align_size))
self.align_end = fdt_util.GetInt(self._node, 'align-end')
self.pos_unset = fdt_util.GetBool(self._node, 'pos-unset')
def ObtainContents(self):
"""Figure out the contents of an entry.
Returns:
True if the contents were found, False if another call is needed
after the other entries are processed.
"""
# No contents by default: subclasses can implement this
return True
def Pack(self, pos):
"""Figure out how to pack the entry into the section
Most of the time the entries are not fully specified. There may be
an alignment but no size. In that case we take the size from the
contents of the entry.
If an entry has no hard-coded position, it will be placed at @pos.
Once this function is complete, both the position and size of the
entry will be know.
Args:
Current section position pointer
Returns:
New section position pointer (after this entry)
"""
if self.pos is None:
if self.pos_unset:
self.Raise('No position set with pos-unset: should another '
'entry provide this correct position?')
self.pos = tools.Align(pos, self.align)
needed = self.pad_before + self.contents_size + self.pad_after
needed = tools.Align(needed, self.align_size)
size = self.size
if not size:
size = needed
new_pos = self.pos + size
aligned_pos = tools.Align(new_pos, self.align_end)
if aligned_pos != new_pos:
size = aligned_pos - self.pos
new_pos = aligned_pos
if not self.size:
self.size = size
if self.size < needed:
self.Raise("Entry contents size is %#x (%d) but entry size is "
"%#x (%d)" % (needed, needed, self.size, self.size))
# Check that the alignment is correct. It could be wrong if the
# and pos or size values were provided (i.e. not calculated), but
# conflict with the provided alignment values
if self.size != tools.Align(self.size, self.align_size):
self.Raise("Size %#x (%d) does not match align-size %#x (%d)" %
(self.size, self.size, self.align_size, self.align_size))
if self.pos != tools.Align(self.pos, self.align):
self.Raise("Position %#x (%d) does not match align %#x (%d)" %
(self.pos, self.pos, self.align, self.align))
return new_pos
def Raise(self, msg):
"""Convenience function to raise an error referencing a node"""
raise ValueError("Node '%s': %s" % (self._node.path, msg))
def GetPath(self):
"""Get the path of a node
Returns:
Full path of the node for this entry
"""
return self._node.path
def GetData(self):
return self.data
def GetPositions(self):
return {}
def SetPositionSize(self, pos, size):
self.pos = pos
self.size = size
def ProcessContents(self):
pass
def WriteSymbols(self, section):
"""Write symbol values into binary files for access at run time
Args:
section: Section containing the entry
"""
pass