u-boot/tools/binman/control.py
Simon Glass 1979063264 binman: Support accessing binman tables at run time
Binman construct images consisting of multiple binary files. These files
sometimes need to know (at run timme) where their peers are located. For
example, SPL may want to know where U-Boot is located in the image, so
that it can jump to U-Boot correctly on boot.

In general the positions where the binaries end up after binman has
finished packing them cannot be known at compile time. One reason for
this is that binman does not know the size of the binaries until
everything is compiled, linked and converted to binaries with objcopy.

To make this work, we add a feature to binman which checks each binary
for symbol names starting with '_binman'. These are then decoded to figure
out which entry and property they refer to. Then binman writes the value
of this symbol into the appropriate binary. With this, the symbol will
have the correct value at run time.

Macros are used to make this easier to use. As an example, this declares
a symbol that will access the 'u-boot-spl' entry to find the 'pos' value
(i.e. the position of SPL in the image):

   binman_sym_declare(unsigned long, u_boot_spl, pos);

This converts to a symbol called '_binman_u_boot_spl_prop_pos' in any
binary that includes it. Binman then updates the value in that binary,
ensuring that it can be accessed at runtime with:

   ulong u_boot_pos = binman_sym(ulong, u_boot_spl, pos);

This assigns the variable u_boot_pos to the position of SPL in the image.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-12-12 19:53:45 -07:00

121 lines
3.7 KiB
Python

# Copyright (c) 2016 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# SPDX-License-Identifier: GPL-2.0+
#
# Creates binary images from input files controlled by a description
#
from collections import OrderedDict
import os
import sys
import tools
import command
import elf
import fdt
import fdt_util
from image import Image
import tout
# List of images we plan to create
# Make this global so that it can be referenced from tests
images = OrderedDict()
def _ReadImageDesc(binman_node):
"""Read the image descriptions from the /binman node
This normally produces a single Image object called 'image'. But if
multiple images are present, they will all be returned.
Args:
binman_node: Node object of the /binman node
Returns:
OrderedDict of Image objects, each of which describes an image
"""
images = OrderedDict()
if 'multiple-images' in binman_node.props:
for node in binman_node.subnodes:
images[node.name] = Image(node.name, node)
else:
images['image'] = Image('image', binman_node)
return images
def _FindBinmanNode(dtb):
"""Find the 'binman' node in the device tree
Args:
dtb: Fdt object to scan
Returns:
Node object of /binman node, or None if not found
"""
for node in dtb.GetRoot().subnodes:
if node.name == 'binman':
return node
return None
def Binman(options, args):
"""The main control code for binman
This assumes that help and test options have already been dealt with. It
deals with the core task of building images.
Args:
options: Command line options object
args: Command line arguments (list of strings)
"""
global images
if options.full_help:
pager = os.getenv('PAGER')
if not pager:
pager = 'more'
fname = os.path.join(os.path.dirname(os.path.realpath(sys.argv[0])),
'README')
command.Run(pager, fname)
return 0
# Try to figure out which device tree contains our image description
if options.dt:
dtb_fname = options.dt
else:
board = options.board
if not board:
raise ValueError('Must provide a board to process (use -b <board>)')
board_pathname = os.path.join(options.build_dir, board)
dtb_fname = os.path.join(board_pathname, 'u-boot.dtb')
if not options.indir:
options.indir = ['.']
options.indir.append(board_pathname)
try:
tout.Init(options.verbosity)
elf.debug = options.debug
try:
tools.SetInputDirs(options.indir)
tools.PrepareOutputDir(options.outdir, options.preserve)
dtb = fdt.FdtScan(dtb_fname)
node = _FindBinmanNode(dtb)
if not node:
raise ValueError("Device tree '%s' does not have a 'binman' "
"node" % dtb_fname)
images = _ReadImageDesc(node)
for image in images.values():
# Perform all steps for this image, including checking and
# writing it. This means that errors found with a later
# image will be reported after earlier images are already
# completed and written, but that does not seem important.
image.GetEntryContents()
image.GetEntryPositions()
image.PackEntries()
image.CheckSize()
image.CheckEntries()
image.ProcessEntryContents()
image.WriteSymbols()
image.BuildImage()
finally:
tools.FinaliseOutputDir()
finally:
tout.Uninit()
return 0