1# SPDX-License-Identifier: GPL-2.0+
2# Copyright (c) 2018 Google, Inc
3# Written by Simon Glass <sjg@chromium.org>
4#
5# Entry-type module for a Flash map, as used by the flashrom SPI flash tool
6#
7
8from binman.entry import Entry
9from binman import fmap_util
10from u_boot_pylib import tools
11from u_boot_pylib.tools import to_hex_size
12from u_boot_pylib import tout
13
14
15class Entry_fmap(Entry):
16    """An entry which contains an Fmap section
17
18    Properties / Entry arguments:
19        None
20
21    FMAP is a simple format used by flashrom, an open-source utility for
22    reading and writing the SPI flash, typically on x86 CPUs. The format
23    provides flashrom with a list of areas, so it knows what it in the flash.
24    It can then read or write just a single area, instead of the whole flash.
25
26    The format is defined by the flashrom project, in the file lib/fmap.h -
27    see www.flashrom.org/Flashrom for more information.
28
29    When used, this entry will be populated with an FMAP which reflects the
30    entries in the current image. Note that any hierarchy is squashed, since
31    FMAP does not support this. Sections are represented as an area appearing
32    before its contents, so that it is possible to reconstruct the hierarchy
33    from the FMAP by using the offset information. This convention does not
34    seem to be documented, but is used in Chromium OS.
35
36    To mark an area as preserved, use the normal 'preserved' flag in the entry.
37    This will result in the corresponding FMAP area having the
38    FMAP_AREA_PRESERVE flag. This flag does not automatically propagate down to
39    child entries.
40
41    CBFS entries appear as a single entry, i.e. the sub-entries are ignored.
42    """
43    def __init__(self, section, etype, node):
44        super().__init__(section, etype, node)
45
46    def _GetFmap(self):
47        """Build an FMAP from the entries in the current image
48
49        Returns:
50            FMAP binary data
51        """
52        def _AddEntries(areas, entry):
53            entries = entry.GetEntries()
54            tout.debug("fmap: Add entry '%s' type '%s' (%s subentries)" %
55                       (entry.GetPath(), entry.etype, to_hex_size(entries)))
56
57            # Collect any flag (separate lines to ensure code coverage)
58            flags = 0
59            if entry.preserve:
60                flags = fmap_util.FMAP_AREA_PRESERVE
61
62            if entries and entry.etype != 'cbfs':
63                # Create an area for the section, which encompasses all entries
64                # within it
65                if entry.image_pos is None:
66                    pos = 0
67                else:
68                    pos = entry.image_pos - entry.GetRootSkipAtStart()
69
70                # Drop @ symbols in name
71                name = entry.name.replace('@', '')
72                areas.append(
73                    fmap_util.FmapArea(pos, entry.size or 0, name, flags))
74                for subentry in entries.values():
75                    _AddEntries(areas, subentry)
76            else:
77                pos = entry.image_pos
78                if pos is not None:
79                    pos -= entry.section.GetRootSkipAtStart()
80                areas.append(fmap_util.FmapArea(pos or 0, entry.size or 0,
81                                                entry.name, flags))
82
83        entries = self.GetImage().GetEntries()
84        areas = []
85        for entry in entries.values():
86            _AddEntries(areas, entry)
87        return fmap_util.EncodeFmap(self.section.GetImageSize() or 0, self.name,
88                                    areas)
89
90    def ObtainContents(self):
91        """Obtain a placeholder for the fmap contents"""
92        self.SetContents(self._GetFmap())
93        return True
94
95    def ProcessContents(self):
96        return self.ProcessContentsUpdate(self._GetFmap())
97