45 lines
1.7 KiB
Python
45 lines
1.7 KiB
Python
# SPDX-License-Identifier: GPL-2.0+
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# Copyright (c) 2016 Google, Inc
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# Written by Simon Glass <sjg@chromium.org>
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#
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# Entry-type module for BSS padding for spl/u-boot-spl.bin. This padding
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# can be added after the SPL binary to ensure that anything concatenated
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# to it will appear to SPL to be at the end of BSS rather than the start.
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#
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from binman import elf
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from binman.entry import Entry
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from binman.etype.blob import Entry_blob
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from patman import tools
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class Entry_u_boot_spl_bss_pad(Entry_blob):
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"""U-Boot SPL binary padded with a BSS region
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Properties / Entry arguments:
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None
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This holds the padding added after the SPL binary to cover the BSS (Block
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Started by Symbol) region. This region holds the various variables used by
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SPL. It is set to 0 by SPL when it starts up. If you want to append data to
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the SPL image (such as a device tree file), you must pad out the BSS region
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to avoid the data overlapping with U-Boot variables. This entry is useful in
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that case. It automatically pads out the entry size to cover both the code,
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data and BSS.
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The contents of this entry will a certain number of zero bytes, determined
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by __bss_size
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The ELF file 'spl/u-boot-spl' must also be available for this to work, since
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binman uses that to look up the BSS address.
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"""
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def __init__(self, section, etype, node):
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super().__init__(section, etype, node)
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def ObtainContents(self):
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fname = tools.GetInputFilename('spl/u-boot-spl')
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bss_size = elf.GetSymbolAddress(fname, '__bss_size')
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if not bss_size:
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self.Raise('Expected __bss_size symbol in spl/u-boot-spl')
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self.SetContents(tools.GetBytes(0, bss_size))
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return True
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