tools/binman/etype/fmap.py

# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2018 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# Entry-type module for a Flash map, as used by the flashrom SPI flash tool
#

from entry import Entry
import fmap_util


class Entry_fmap(Entry):
    """An entry which contains an Fmap section

    Properties / Entry arguments:
        None

    FMAP is a simple format used by flashrom, an open-source utility for
    reading and writing the SPI flash, typically on x86 CPUs. The format
    provides flashrom with a list of areas, so it knows what it in the flash.
    It can then read or write just a single area, instead of the whole flash.

    The format is defined by the flashrom project, in the file lib/fmap.h -
    see www.flashrom.org/Flashrom for more information.

    When used, this entry will be populated with an FMAP which reflects the
    entries in the current image. Note that any hierarchy is squashed, since
    FMAP does not support this.
    """
    def __init__(self, section, etype, node):
        Entry.__init__(self, section, etype, node)

    def _GetFmap(self):
        """Build an FMAP from the entries in the current image

        Returns:
            FMAP binary data
        """
        def _AddEntries(areas, entry):
            entries = entry.GetEntries()
            if entries:
                for subentry in entries.values():
                    _AddEntries(areas, subentry)
            else:
                pos = entry.image_pos
                if pos is not None:
                    pos -= entry.section.GetRootSkipAtStart()
                areas.append(fmap_util.FmapArea(pos or 0, entry.size or 0,
                                                entry.name, 0))

        entries = self.section._image.GetEntries()
        areas = []
        for entry in entries.values():
            _AddEntries(areas, entry)
        return fmap_util.EncodeFmap(self.section.GetImageSize() or 0, self.name,
                                    areas)

    def ObtainContents(self):
        """Obtain a placeholder for the fmap contents"""
        self.SetContents(self._GetFmap())
        return True

    def ProcessContents(self):
        self.SetContents(self._GetFmap())