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For scenarios like OF_BOARD or OF_PRIOR_STAGE, no device tree blob is provided in the U-Boot build phase hence the binman node information is not available. In order to support such use case, a new Kconfig option BINMAN_STANDALONE_FDT is introduced, to tell the build system that a device tree blob containing binman node is explicitly required when using binman to package U-Boot. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
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46 KiB
ReStructuredText
1193 lines
46 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
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.. Copyright (c) 2016 Google, Inc
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Introduction
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============
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Firmware often consists of several components which must be packaged together.
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For example, we may have SPL, U-Boot, a device tree and an environment area
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grouped together and placed in MMC flash. When the system starts, it must be
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able to find these pieces.
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Building firmware should be separate from packaging it. Many of the complexities
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of modern firmware build systems come from trying to do both at once. With
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binman, you build all the pieces that are needed, using whatever assortment of
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projects and build systems are needed, then use binman to stitch everything
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together.
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What it does
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------------
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Binman reads your board's device tree and finds a node which describes the
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required image layout. It uses this to work out what to place where.
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Binman provides a mechanism for building images, from simple SPL + U-Boot
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combinations, to more complex arrangements with many parts. It also allows
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users to inspect images, extract and replace binaries within them, repacking if
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needed.
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Features
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--------
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Apart from basic padding, alignment and positioning features, Binman supports
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hierarchical images, compression, hashing and dealing with the binary blobs
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which are a sad trend in open-source firmware at present.
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Executable binaries can access the location of other binaries in an image by
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using special linker symbols (zero-overhead but somewhat limited) or by reading
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the devicetree description of the image.
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Binman is designed primarily for use with U-Boot and associated binaries such
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as ARM Trusted Firmware, but it is suitable for use with other projects, such
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as Zephyr. Binman also provides facilities useful in Chromium OS, such as CBFS,
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vblocks and and the like.
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Binman provides a way to process binaries before they are included, by adding a
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Python plug-in.
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Binman is intended for use with U-Boot but is designed to be general enough
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to be useful in other image-packaging situations.
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Motivation
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----------
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As mentioned above, packaging of firmware is quite a different task from
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building the various parts. In many cases the various binaries which go into
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the image come from separate build systems. For example, ARM Trusted Firmware
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is used on ARMv8 devices but is not built in the U-Boot tree. If a Linux kernel
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is included in the firmware image, it is built elsewhere.
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It is of course possible to add more and more build rules to the U-Boot
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build system to cover these cases. It can shell out to other Makefiles and
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build scripts. But it seems better to create a clear divide between building
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software and packaging it.
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At present this is handled by manual instructions, different for each board,
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on how to create images that will boot. By turning these instructions into a
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standard format, we can support making valid images for any board without
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manual effort, lots of READMEs, etc.
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Benefits:
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- Each binary can have its own build system and tool chain without creating
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any dependencies between them
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- Avoids the need for a single-shot build: individual parts can be updated
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and brought in as needed
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- Provides for a standard image description available in the build and at
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run-time
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- SoC-specific image-signing tools can be accommodated
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- Avoids cluttering the U-Boot build system with image-building code
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- The image description is automatically available at run-time in U-Boot,
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SPL. It can be made available to other software also
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- The image description is easily readable (it's a text file in device-tree
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format) and permits flexible packing of binaries
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Terminology
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-----------
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Binman uses the following terms:
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- image - an output file containing a firmware image
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- binary - an input binary that goes into the image
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Relationship to FIT
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-------------------
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FIT is U-Boot's official image format. It supports multiple binaries with
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load / execution addresses, compression. It also supports verification
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through hashing and RSA signatures.
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FIT was originally designed to support booting a Linux kernel (with an
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optional ramdisk) and device tree chosen from various options in the FIT.
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Now that U-Boot supports configuration via device tree, it is possible to
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load U-Boot from a FIT, with the device tree chosen by SPL.
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Binman considers FIT to be one of the binaries it can place in the image.
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Where possible it is best to put as much as possible in the FIT, with binman
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used to deal with cases not covered by FIT. Examples include initial
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execution (since FIT itself does not have an executable header) and dealing
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with device boundaries, such as the read-only/read-write separation in SPI
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flash.
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For U-Boot, binman should not be used to create ad-hoc images in place of
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FIT.
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Relationship to mkimage
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-----------------------
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The mkimage tool provides a means to create a FIT. Traditionally it has
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needed an image description file: a device tree, like binman, but in a
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different format. More recently it has started to support a '-f auto' mode
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which can generate that automatically.
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More relevant to binman, mkimage also permits creation of many SoC-specific
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image types. These can be listed by running 'mkimage -T list'. Examples
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include 'rksd', the Rockchip SD/MMC boot format. The mkimage tool is often
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called from the U-Boot build system for this reason.
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Binman considers the output files created by mkimage to be binary blobs
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which it can place in an image. Binman does not replace the mkimage tool or
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this purpose. It would be possible in some situations to create a new entry
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type for the images in mkimage, but this would not add functionality. It
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seems better to use the mkimage tool to generate binaries and avoid blurring
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the boundaries between building input files (mkimage) and packaging then
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into a final image (binman).
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Using binman
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============
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Example use of binman in U-Boot
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-------------------------------
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Binman aims to replace some of the ad-hoc image creation in the U-Boot
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build system.
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Consider sunxi. It has the following steps:
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#. It uses a custom mksunxiboot tool to build an SPL image called
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sunxi-spl.bin. This should probably move into mkimage.
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#. It uses mkimage to package U-Boot into a legacy image file (so that it can
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hold the load and execution address) called u-boot.img.
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#. It builds a final output image called u-boot-sunxi-with-spl.bin which
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consists of sunxi-spl.bin, some padding and u-boot.img.
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Binman is intended to replace the last step. The U-Boot build system builds
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u-boot.bin and sunxi-spl.bin. Binman can then take over creation of
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sunxi-spl.bin (by calling mksunxiboot, or hopefully one day mkimage). In any
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case, it would then create the image from the component parts.
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This simplifies the U-Boot Makefile somewhat, since various pieces of logic
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can be replaced by a call to binman.
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Example use of binman for x86
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-----------------------------
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In most cases x86 images have a lot of binary blobs, 'black-box' code
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provided by Intel which must be run for the platform to work. Typically
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these blobs are not relocatable and must be placed at fixed areas in the
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firmware image.
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Currently this is handled by ifdtool, which places microcode, FSP, MRC, VGA
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BIOS, reference code and Intel ME binaries into a u-boot.rom file.
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Binman is intended to replace all of this, with ifdtool left to handle only
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the configuration of the Intel-format descriptor.
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Running binman
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--------------
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First install prerequisites, e.g::
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sudo apt-get install python-pyelftools python3-pyelftools lzma-alone \
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liblz4-tool
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Type::
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binman build -b <board_name>
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to build an image for a board. The board name is the same name used when
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configuring U-Boot (e.g. for sandbox_defconfig the board name is 'sandbox').
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Binman assumes that the input files for the build are in ../b/<board_name>.
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Or you can specify this explicitly::
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binman build -I <build_path>
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where <build_path> is the build directory containing the output of the U-Boot
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build.
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(Future work will make this more configurable)
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In either case, binman picks up the device tree file (u-boot.dtb) and looks
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for its instructions in the 'binman' node.
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Binman has a few other options which you can see by running 'binman -h'.
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Enabling binman for a board
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---------------------------
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At present binman is invoked from a rule in the main Makefile. You should be
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able to enable CONFIG_BINMAN to enable this rule.
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The output file is typically named image.bin and is located in the output
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directory. If input files are needed to you add these to INPUTS-y either in the
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main Makefile or in a config.mk file in your arch subdirectory.
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Once binman is executed it will pick up its instructions from a device-tree
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file, typically <soc>-u-boot.dtsi, where <soc> is your CONFIG_SYS_SOC value.
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You can use other, more specific CONFIG options - see 'Automatic .dtsi
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inclusion' below.
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Using binman with OF_BOARD or OF_PRIOR_STAGE
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--------------------------------------------
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Normally binman is used with a board configured with OF_SEPARATE or OF_EMBED.
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This is a typical scenario where a device tree source that contains the binman
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node is provided in the arch/<arch>/dts directory for a specific board.
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However for a board configured with OF_BOARD or OF_PRIOR_STAGE, no device tree
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blob is provided in the U-Boot build phase hence the binman node information
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is not available. In order to support such use case, a new Kconfig option
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BINMAN_STANDALONE_FDT is introduced, to tell the build system that a standalone
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device tree blob containing binman node is explicitly required.
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Note there is a Kconfig option BINMAN_FDT which enables U-Boot run time to
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access information about binman entries, stored in the device tree in a binman
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node. Generally speaking, this option makes sense for OF_SEPARATE or OF_EMBED.
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For the other OF_CONTROL methods, it's quite possible binman node is not
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available as binman is invoked during the build phase, thus this option is not
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turned on by default for these OF_CONTROL methods.
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See qemu-riscv64_spl_defconfig for an example of how binman is used with
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OF_PRIOR_STAGE to generate u-boot.itb image.
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Access to binman entry offsets at run time (symbols)
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----------------------------------------------------
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Binman assembles images and determines where each entry is placed in the image.
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This information may be useful to U-Boot at run time. For example, in SPL it
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is useful to be able to find the location of U-Boot so that it can be executed
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when SPL is finished.
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Binman allows you to declare symbols in the SPL image which are filled in
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with their correct values during the build. For example::
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binman_sym_declare(ulong, u_boot_any, image_pos);
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declares a ulong value which will be assigned to the image-pos of any U-Boot
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image (u-boot.bin, u-boot.img, u-boot-nodtb.bin) that is present in the image.
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You can access this value with something like::
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ulong u_boot_offset = binman_sym(ulong, u_boot_any, image_pos);
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Thus u_boot_offset will be set to the image-pos of U-Boot in memory, assuming
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that the whole image has been loaded, or is available in flash. You can then
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jump to that address to start U-Boot.
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At present this feature is only supported in SPL and TPL. In principle it is
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possible to fill in such symbols in U-Boot proper, as well, but a future C
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library is planned for this instead, to read from the device tree.
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As well as image-pos, it is possible to read the size of an entry and its
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offset (which is the start position of the entry within its parent).
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A small technical note: Binman automatically adds the base address of the image
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(i.e. __image_copy_start) to the value of the image-pos symbol, so that when the
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image is loaded to its linked address, the value will be correct and actually
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point into the image.
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For example, say SPL is at the start of the image and linked to start at address
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80108000. If U-Boot's image-pos is 0x8000 then binman will write an image-pos
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for U-Boot of 80110000 into the SPL binary, since it assumes the image is loaded
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to 80108000, with SPL at 80108000 and U-Boot at 80110000.
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For x86 devices (with the end-at-4gb property) this base address is not added
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since it is assumed that images are XIP and the offsets already include the
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address.
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Access to binman entry offsets at run time (fdt)
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------------------------------------------------
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Binman can update the U-Boot FDT to include the final position and size of
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each entry in the images it processes. The option to enable this is -u and it
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causes binman to make sure that the 'offset', 'image-pos' and 'size' properties
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are set correctly for every entry. Since it is not necessary to specify these in
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the image definition, binman calculates the final values and writes these to
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the device tree. These can be used by U-Boot at run-time to find the location
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of each entry.
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Alternatively, an FDT map entry can be used to add a special FDT containing
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just the information about the image. This is preceded by a magic string so can
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be located anywhere in the image. An image header (typically at the start or end
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of the image) can be used to point to the FDT map. See fdtmap and image-header
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entries for more information.
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Map files
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---------
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The -m option causes binman to output a .map file for each image that it
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generates. This shows the offset and size of each entry. For example::
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Offset Size Name
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00000000 00000028 main-section
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00000000 00000010 section@0
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00000000 00000004 u-boot
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00000010 00000010 section@1
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00000000 00000004 u-boot
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This shows a hierarchical image with two sections, each with a single entry. The
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offsets of the sections are absolute hex byte offsets within the image. The
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offsets of the entries are relative to their respective sections. The size of
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each entry is also shown, in bytes (hex). The indentation shows the entries
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nested inside their sections.
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Passing command-line arguments to entries
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-----------------------------------------
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Sometimes it is useful to pass binman the value of an entry property from the
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command line. For example some entries need access to files and it is not
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always convenient to put these filenames in the image definition (device tree).
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The -a option supports this::
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-a <prop>=<value>
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where::
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<prop> is the property to set
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<value> is the value to set it to
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Not all properties can be provided this way. Only some entries support it,
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typically for filenames.
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Image description format
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========================
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The binman node is called 'binman'. An example image description is shown
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below::
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binman {
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filename = "u-boot-sunxi-with-spl.bin";
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pad-byte = <0xff>;
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blob {
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filename = "spl/sunxi-spl.bin";
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};
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u-boot {
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offset = <CONFIG_SPL_PAD_TO>;
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};
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};
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This requests binman to create an image file called u-boot-sunxi-with-spl.bin
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consisting of a specially formatted SPL (spl/sunxi-spl.bin, built by the
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normal U-Boot Makefile), some 0xff padding, and a U-Boot legacy image. The
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padding comes from the fact that the second binary is placed at
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CONFIG_SPL_PAD_TO. If that line were omitted then the U-Boot binary would
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immediately follow the SPL binary.
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The binman node describes an image. The sub-nodes describe entries in the
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image. Each entry represents a region within the overall image. The name of
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the entry (blob, u-boot) tells binman what to put there. For 'blob' we must
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provide a filename. For 'u-boot', binman knows that this means 'u-boot.bin'.
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Entries are normally placed into the image sequentially, one after the other.
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The image size is the total size of all entries. As you can see, you can
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specify the start offset of an entry using the 'offset' property.
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Note that due to a device tree requirement, all entries must have a unique
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name. If you want to put the same binary in the image multiple times, you can
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use any unique name, with the 'type' property providing the type.
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The attributes supported for entries are described below.
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offset:
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This sets the offset of an entry within the image or section containing
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it. The first byte of the image is normally at offset 0. If 'offset' is
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not provided, binman sets it to the end of the previous region, or the
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start of the image's entry area (normally 0) if there is no previous
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region.
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align:
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This sets the alignment of the entry. The entry offset is adjusted
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so that the entry starts on an aligned boundary within the containing
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section or image. For example 'align = <16>' means that the entry will
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start on a 16-byte boundary. This may mean that padding is added before
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the entry. The padding is part of the containing section but is not
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included in the entry, meaning that an empty space may be created before
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the entry starts. Alignment should be a power of 2. If 'align' is not
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provided, no alignment is performed.
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size:
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This sets the size of the entry. The contents will be padded out to
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this size. If this is not provided, it will be set to the size of the
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contents.
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pad-before:
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Padding before the contents of the entry. Normally this is 0, meaning
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that the contents start at the beginning of the entry. This can be used
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to offset the entry contents a little. While this does not affect the
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contents of the entry within binman itself (the padding is performed
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only when its parent section is assembled), the end result will be that
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the entry starts with the padding bytes, so may grow. Defaults to 0.
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pad-after:
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Padding after the contents of the entry. Normally this is 0, meaning
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that the entry ends at the last byte of content (unless adjusted by
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other properties). This allows room to be created in the image for
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this entry to expand later. While this does not affect the contents of
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the entry within binman itself (the padding is performed only when its
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parent section is assembled), the end result will be that the entry ends
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with the padding bytes, so may grow. Defaults to 0.
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align-size:
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This sets the alignment of the entry size. For example, to ensure
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that the size of an entry is a multiple of 64 bytes, set this to 64.
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While this does not affect the contents of the entry within binman
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itself (the padding is performed only when its parent section is
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assembled), the end result is that the entry ends with the padding
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bytes, so may grow. If 'align-size' is not provided, no alignment is
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performed.
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align-end:
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This sets the alignment of the end of an entry with respect to the
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containing section. Some entries require that they end on an alignment
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boundary, regardless of where they start. This does not move the start
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of the entry, so the contents of the entry will still start at the
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beginning. But there may be padding at the end. While this does not
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affect the contents of the entry within binman itself (the padding is
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performed only when its parent section is assembled), the end result
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is that the entry ends with the padding bytes, so may grow.
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If 'align-end' is not provided, no alignment is performed.
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filename:
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For 'blob' types this provides the filename containing the binary to
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put into the entry. If binman knows about the entry type (like
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u-boot-bin), then there is no need to specify this.
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type:
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Sets the type of an entry. This defaults to the entry name, but it is
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possible to use any name, and then add (for example) 'type = "u-boot"'
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to specify the type.
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offset-unset:
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Indicates that the offset of this entry should not be set by placing
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it immediately after the entry before. Instead, is set by another
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entry which knows where this entry should go. When this boolean
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property is present, binman will give an error if another entry does
|
|
not set the offset (with the GetOffsets() method).
|
|
|
|
image-pos:
|
|
This cannot be set on entry (or at least it is ignored if it is), but
|
|
with the -u option, binman will set it to the absolute image position
|
|
for each entry. This makes it easy to find out exactly where the entry
|
|
ended up in the image, regardless of parent sections, etc.
|
|
|
|
expand-size:
|
|
Expand the size of this entry to fit available space. This space is only
|
|
limited by the size of the image/section and the position of the next
|
|
entry.
|
|
|
|
compress:
|
|
Sets the compression algortihm to use (for blobs only). See the entry
|
|
documentation for details.
|
|
|
|
missing-msg:
|
|
Sets the tag of the message to show if this entry is missing. This is
|
|
used for external blobs. When they are missing it is helpful to show
|
|
information about what needs to be fixed. See missing-blob-help for the
|
|
message for each tag.
|
|
|
|
no-expanded:
|
|
By default binman substitutes entries with expanded versions if available,
|
|
so that a `u-boot` entry type turns into `u-boot-expanded`, for example. The
|
|
`--no-expanded` command-line option disables this globally. The
|
|
`no-expanded` property disables this just for a single entry. Put the
|
|
`no-expanded` boolean property in the node to select this behaviour.
|
|
|
|
The attributes supported for images and sections are described below. Several
|
|
are similar to those for entries.
|
|
|
|
size:
|
|
Sets the image size in bytes, for example 'size = <0x100000>' for a
|
|
1MB image.
|
|
|
|
offset:
|
|
This is similar to 'offset' in entries, setting the offset of a section
|
|
within the image or section containing it. The first byte of the section
|
|
is normally at offset 0. If 'offset' is not provided, binman sets it to
|
|
the end of the previous region, or the start of the image's entry area
|
|
(normally 0) if there is no previous region.
|
|
|
|
align-size:
|
|
This sets the alignment of the image size. For example, to ensure
|
|
that the image ends on a 512-byte boundary, use 'align-size = <512>'.
|
|
If 'align-size' is not provided, no alignment is performed.
|
|
|
|
pad-before:
|
|
This sets the padding before the image entries. The first entry will
|
|
be positioned after the padding. This defaults to 0.
|
|
|
|
pad-after:
|
|
This sets the padding after the image entries. The padding will be
|
|
placed after the last entry. This defaults to 0.
|
|
|
|
pad-byte:
|
|
This specifies the pad byte to use when padding in the image. It
|
|
defaults to 0. To use 0xff, you would add 'pad-byte = <0xff>'.
|
|
|
|
filename:
|
|
This specifies the image filename. It defaults to 'image.bin'.
|
|
|
|
sort-by-offset:
|
|
This causes binman to reorder the entries as needed to make sure they
|
|
are in increasing positional order. This can be used when your entry
|
|
order may not match the positional order. A common situation is where
|
|
the 'offset' properties are set by CONFIG options, so their ordering is
|
|
not known a priori.
|
|
|
|
This is a boolean property so needs no value. To enable it, add a
|
|
line 'sort-by-offset;' to your description.
|
|
|
|
multiple-images:
|
|
Normally only a single image is generated. To create more than one
|
|
image, put this property in the binman node. For example, this will
|
|
create image1.bin containing u-boot.bin, and image2.bin containing
|
|
both spl/u-boot-spl.bin and u-boot.bin::
|
|
|
|
binman {
|
|
multiple-images;
|
|
image1 {
|
|
u-boot {
|
|
};
|
|
};
|
|
|
|
image2 {
|
|
spl {
|
|
};
|
|
u-boot {
|
|
};
|
|
};
|
|
};
|
|
|
|
end-at-4gb:
|
|
For x86 machines the ROM offsets start just before 4GB and extend
|
|
up so that the image finished at the 4GB boundary. This boolean
|
|
option can be enabled to support this. The image size must be
|
|
provided so that binman knows when the image should start. For an
|
|
8MB ROM, the offset of the first entry would be 0xfff80000 with
|
|
this option, instead of 0 without this option.
|
|
|
|
skip-at-start:
|
|
This property specifies the entry offset of the first entry.
|
|
|
|
For PowerPC mpc85xx based CPU, CONFIG_SYS_TEXT_BASE is the entry
|
|
offset of the first entry. It can be 0xeff40000 or 0xfff40000 for
|
|
nor flash boot, 0x201000 for sd boot etc.
|
|
|
|
'end-at-4gb' property is not applicable where CONFIG_SYS_TEXT_BASE +
|
|
Image size != 4gb.
|
|
|
|
align-default:
|
|
Specifies the default alignment for entries in this section, if they do
|
|
not specify an alignment. Note that this only applies to top-level entries
|
|
in the section (direct subentries), not any subentries of those entries.
|
|
This means that each section must specify its own default alignment, if
|
|
required.
|
|
|
|
Examples of the above options can be found in the tests. See the
|
|
tools/binman/test directory.
|
|
|
|
It is possible to have the same binary appear multiple times in the image,
|
|
either by using a unit number suffix (u-boot@0, u-boot@1) or by using a
|
|
different name for each and specifying the type with the 'type' attribute.
|
|
|
|
|
|
Sections and hierachical images
|
|
-------------------------------
|
|
|
|
Sometimes it is convenient to split an image into several pieces, each of which
|
|
contains its own set of binaries. An example is a flash device where part of
|
|
the image is read-only and part is read-write. We can set up sections for each
|
|
of these, and place binaries in them independently. The image is still produced
|
|
as a single output file.
|
|
|
|
This feature provides a way of creating hierarchical images. For example here
|
|
is an example image with two copies of U-Boot. One is read-only (ro), intended
|
|
to be written only in the factory. Another is read-write (rw), so that it can be
|
|
upgraded in the field. The sizes are fixed so that the ro/rw boundary is known
|
|
and can be programmed::
|
|
|
|
binman {
|
|
section@0 {
|
|
read-only;
|
|
name-prefix = "ro-";
|
|
size = <0x100000>;
|
|
u-boot {
|
|
};
|
|
};
|
|
section@1 {
|
|
name-prefix = "rw-";
|
|
size = <0x100000>;
|
|
u-boot {
|
|
};
|
|
};
|
|
};
|
|
|
|
This image could be placed into a SPI flash chip, with the protection boundary
|
|
set at 1MB.
|
|
|
|
A few special properties are provided for sections:
|
|
|
|
read-only:
|
|
Indicates that this section is read-only. This has no impact on binman's
|
|
operation, but his property can be read at run time.
|
|
|
|
name-prefix:
|
|
This string is prepended to all the names of the binaries in the
|
|
section. In the example above, the 'u-boot' binaries which actually be
|
|
renamed to 'ro-u-boot' and 'rw-u-boot'. This can be useful to
|
|
distinguish binaries with otherwise identical names.
|
|
|
|
|
|
Image Properties
|
|
----------------
|
|
|
|
Image nodes act like sections but also have a few extra properties:
|
|
|
|
filename:
|
|
Output filename for the image. This defaults to image.bin (or in the
|
|
case of multiple images <nodename>.bin where <nodename> is the name of
|
|
the image node.
|
|
|
|
allow-repack:
|
|
Create an image that can be repacked. With this option it is possible
|
|
to change anything in the image after it is created, including updating
|
|
the position and size of image components. By default this is not
|
|
permitted since it is not possibly to know whether this might violate a
|
|
constraint in the image description. For example, if a section has to
|
|
increase in size to hold a larger binary, that might cause the section
|
|
to fall out of its allow region (e.g. read-only portion of flash).
|
|
|
|
Adding this property causes the original offset and size values in the
|
|
image description to be stored in the FDT and fdtmap.
|
|
|
|
|
|
Hashing Entries
|
|
---------------
|
|
|
|
It is possible to ask binman to hash the contents of an entry and write that
|
|
value back to the device-tree node. For example::
|
|
|
|
binman {
|
|
u-boot {
|
|
hash {
|
|
algo = "sha256";
|
|
};
|
|
};
|
|
};
|
|
|
|
Here, a new 'value' property will be written to the 'hash' node containing
|
|
the hash of the 'u-boot' entry. Only SHA256 is supported at present. Whole
|
|
sections can be hased if desired, by adding the 'hash' node to the section.
|
|
|
|
The has value can be chcked at runtime by hashing the data actually read and
|
|
comparing this has to the value in the device tree.
|
|
|
|
|
|
Expanded entries
|
|
----------------
|
|
|
|
Binman automatically replaces 'u-boot' with an expanded version of that, i.e.
|
|
'u-boot-expanded'. This means that when you write::
|
|
|
|
u-boot {
|
|
};
|
|
|
|
you actually get::
|
|
|
|
u-boot {
|
|
type = "u-boot-expanded';
|
|
};
|
|
|
|
which in turn expands to::
|
|
|
|
u-boot {
|
|
type = "section";
|
|
|
|
u-boot-nodtb {
|
|
};
|
|
|
|
u-boot-dtb {
|
|
};
|
|
};
|
|
|
|
U-Boot's various phase binaries actually comprise two or three pieces.
|
|
For example, u-boot.bin has the executable followed by a devicetree.
|
|
|
|
With binman we want to be able to update that devicetree with full image
|
|
information so that it is accessible to the executable. This is tricky
|
|
if it is not clear where the devicetree starts.
|
|
|
|
The above feature ensures that the devicetree is clearly separated from the
|
|
U-Boot executable and can be updated separately by binman as needed. It can be
|
|
disabled with the --no-expanded flag if required.
|
|
|
|
The same applies for u-boot-spl and u-boot-spl. In those cases, the expansion
|
|
includes the BSS padding, so for example::
|
|
|
|
spl {
|
|
type = "u-boot-spl"
|
|
};
|
|
|
|
you actually get::
|
|
|
|
spl {
|
|
type = "u-boot-expanded';
|
|
};
|
|
|
|
which in turn expands to::
|
|
|
|
spl {
|
|
type = "section";
|
|
|
|
u-boot-spl-nodtb {
|
|
};
|
|
|
|
u-boot-spl-bss-pad {
|
|
};
|
|
|
|
u-boot-spl-dtb {
|
|
};
|
|
};
|
|
|
|
Of course we should not expand SPL if it has no devicetree. Also if the BSS
|
|
padding is not needed (because BSS is in RAM as with CONFIG_SPL_SEPARATE_BSS),
|
|
the 'u-boot-spl-bss-pad' subnode should not be created. The use of the expaned
|
|
entry type is controlled by the UseExpanded() method. In the SPL case it checks
|
|
the 'spl-dtb' entry arg, which is 'y' or '1' if SPL has a devicetree.
|
|
|
|
For the BSS case, a 'spl-bss-pad' entry arg controls whether it is present. All
|
|
entry args are provided by the U-Boot Makefile.
|
|
|
|
|
|
Compression
|
|
-----------
|
|
|
|
Binman support compression for 'blob' entries (those of type 'blob' and
|
|
derivatives). To enable this for an entry, add a 'compress' property::
|
|
|
|
blob {
|
|
filename = "datafile";
|
|
compress = "lz4";
|
|
};
|
|
|
|
The entry will then contain the compressed data, using the 'lz4' compression
|
|
algorithm. Currently this is the only one that is supported. The uncompressed
|
|
size is written to the node in an 'uncomp-size' property, if -u is used.
|
|
|
|
Compression is also supported for sections. In that case the entire section is
|
|
compressed in one block, including all its contents. This means that accessing
|
|
an entry from the section required decompressing the entire section. Also, the
|
|
size of a section indicates the space that it consumes in its parent section
|
|
(and typically the image). With compression, the section may contain more data,
|
|
and the uncomp-size property indicates that, as above. The contents of the
|
|
section is compressed first, before any padding is added. This ensures that the
|
|
padding itself is not compressed, which would be a waste of time.
|
|
|
|
|
|
Automatic .dtsi inclusion
|
|
-------------------------
|
|
|
|
It is sometimes inconvenient to add a 'binman' node to the .dts file for each
|
|
board. This can be done by using #include to bring in a common file. Another
|
|
approach supported by the U-Boot build system is to automatically include
|
|
a common header. You can then put the binman node (and anything else that is
|
|
specific to U-Boot, such as u-boot,dm-pre-reloc properies) in that header
|
|
file.
|
|
|
|
Binman will search for the following files in arch/<arch>/dts::
|
|
|
|
<dts>-u-boot.dtsi where <dts> is the base name of the .dts file
|
|
<CONFIG_SYS_SOC>-u-boot.dtsi
|
|
<CONFIG_SYS_CPU>-u-boot.dtsi
|
|
<CONFIG_SYS_VENDOR>-u-boot.dtsi
|
|
u-boot.dtsi
|
|
|
|
U-Boot will only use the first one that it finds. If you need to include a
|
|
more general file you can do that from the more specific file using #include.
|
|
If you are having trouble figuring out what is going on, you can uncomment
|
|
the 'warning' line in scripts/Makefile.lib to see what it has found::
|
|
|
|
# Uncomment for debugging
|
|
# This shows all the files that were considered and the one that we chose.
|
|
# u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
|
|
|
|
|
|
Entry Documentation
|
|
===================
|
|
|
|
For details on the various entry types supported by binman and how to use them,
|
|
see entries.rst which is generated from the source code using:
|
|
|
|
binman entry-docs >tools/binman/entries.rst
|
|
|
|
.. toctree::
|
|
:maxdepth: 2
|
|
|
|
entries
|
|
|
|
|
|
Managing images
|
|
===============
|
|
|
|
Listing images
|
|
--------------
|
|
|
|
It is possible to list the entries in an existing firmware image created by
|
|
binman, provided that there is an 'fdtmap' entry in the image. For example::
|
|
|
|
$ binman ls -i image.bin
|
|
Name Image-pos Size Entry-type Offset Uncomp-size
|
|
----------------------------------------------------------------------
|
|
main-section c00 section 0
|
|
u-boot 0 4 u-boot 0
|
|
section 5fc section 4
|
|
cbfs 100 400 cbfs 0
|
|
u-boot 138 4 u-boot 38
|
|
u-boot-dtb 180 108 u-boot-dtb 80 3b5
|
|
u-boot-dtb 500 1ff u-boot-dtb 400 3b5
|
|
fdtmap 6fc 381 fdtmap 6fc
|
|
image-header bf8 8 image-header bf8
|
|
|
|
This shows the hierarchy of the image, the position, size and type of each
|
|
entry, the offset of each entry within its parent and the uncompressed size if
|
|
the entry is compressed.
|
|
|
|
It is also possible to list just some files in an image, e.g.::
|
|
|
|
$ binman ls -i image.bin section/cbfs
|
|
Name Image-pos Size Entry-type Offset Uncomp-size
|
|
--------------------------------------------------------------------
|
|
cbfs 100 400 cbfs 0
|
|
u-boot 138 4 u-boot 38
|
|
u-boot-dtb 180 108 u-boot-dtb 80 3b5
|
|
|
|
or with wildcards::
|
|
|
|
$ binman ls -i image.bin "*cb*" "*head*"
|
|
Name Image-pos Size Entry-type Offset Uncomp-size
|
|
----------------------------------------------------------------------
|
|
cbfs 100 400 cbfs 0
|
|
u-boot 138 4 u-boot 38
|
|
u-boot-dtb 180 108 u-boot-dtb 80 3b5
|
|
image-header bf8 8 image-header bf8
|
|
|
|
|
|
Extracting files from images
|
|
----------------------------
|
|
|
|
You can extract files from an existing firmware image created by binman,
|
|
provided that there is an 'fdtmap' entry in the image. For example::
|
|
|
|
$ binman extract -i image.bin section/cbfs/u-boot
|
|
|
|
which will write the uncompressed contents of that entry to the file 'u-boot' in
|
|
the current directory. You can also extract to a particular file, in this case
|
|
u-boot.bin::
|
|
|
|
$ binman extract -i image.bin section/cbfs/u-boot -f u-boot.bin
|
|
|
|
It is possible to extract all files into a destination directory, which will
|
|
put files in subdirectories matching the entry hierarchy::
|
|
|
|
$ binman extract -i image.bin -O outdir
|
|
|
|
or just a selection::
|
|
|
|
$ binman extract -i image.bin "*u-boot*" -O outdir
|
|
|
|
|
|
Replacing files in an image
|
|
---------------------------
|
|
|
|
You can replace files in an existing firmware image created by binman, provided
|
|
that there is an 'fdtmap' entry in the image. For example:
|
|
|
|
$ binman replace -i image.bin section/cbfs/u-boot
|
|
|
|
which will write the contents of the file 'u-boot' from the current directory
|
|
to the that entry, compressing if necessary. If the entry size changes, you must
|
|
add the 'allow-repack' property to the original image before generating it (see
|
|
above), otherwise you will get an error.
|
|
|
|
You can also use a particular file, in this case u-boot.bin::
|
|
|
|
$ binman replace -i image.bin section/cbfs/u-boot -f u-boot.bin
|
|
|
|
It is possible to replace all files from a source directory which uses the same
|
|
hierarchy as the entries::
|
|
|
|
$ binman replace -i image.bin -I indir
|
|
|
|
Files that are missing will generate a warning.
|
|
|
|
You can also replace just a selection of entries::
|
|
|
|
$ binman replace -i image.bin "*u-boot*" -I indir
|
|
|
|
|
|
Logging
|
|
-------
|
|
|
|
Binman normally operates silently unless there is an error, in which case it
|
|
just displays the error. The -D/--debug option can be used to create a full
|
|
backtrace when errors occur. You can use BINMAN_DEBUG=1 when building to select
|
|
this.
|
|
|
|
Internally binman logs some output while it is running. This can be displayed
|
|
by increasing the -v/--verbosity from the default of 1:
|
|
|
|
0: silent
|
|
1: warnings only
|
|
2: notices (important messages)
|
|
3: info about major operations
|
|
4: detailed information about each operation
|
|
5: debug (all output)
|
|
|
|
You can use BINMAN_VERBOSE=5 (for example) when building to select this.
|
|
|
|
|
|
Technical details
|
|
=================
|
|
|
|
Order of image creation
|
|
-----------------------
|
|
|
|
Image creation proceeds in the following order, for each entry in the image.
|
|
|
|
1. AddMissingProperties() - binman can add calculated values to the device
|
|
tree as part of its processing, for example the offset and size of each
|
|
entry. This method adds any properties associated with this, expanding the
|
|
device tree as needed. These properties can have placeholder values which are
|
|
set later by SetCalculatedProperties(). By that stage the size of sections
|
|
cannot be changed (since it would cause the images to need to be repacked),
|
|
but the correct values can be inserted.
|
|
|
|
2. ProcessFdt() - process the device tree information as required by the
|
|
particular entry. This may involve adding or deleting properties. If the
|
|
processing is complete, this method should return True. If the processing
|
|
cannot complete because it needs the ProcessFdt() method of another entry to
|
|
run first, this method should return False, in which case it will be called
|
|
again later.
|
|
|
|
3. GetEntryContents() - the contents of each entry are obtained, normally by
|
|
reading from a file. This calls the Entry.ObtainContents() to read the
|
|
contents. The default version of Entry.ObtainContents() calls
|
|
Entry.GetDefaultFilename() and then reads that file. So a common mechanism
|
|
to select a file to read is to override that function in the subclass. The
|
|
functions must return True when they have read the contents. Binman will
|
|
retry calling the functions a few times if False is returned, allowing
|
|
dependencies between the contents of different entries.
|
|
|
|
4. GetEntryOffsets() - calls Entry.GetOffsets() for each entry. This can
|
|
return a dict containing entries that need updating. The key should be the
|
|
entry name and the value is a tuple (offset, size). This allows an entry to
|
|
provide the offset and size for other entries. The default implementation
|
|
of GetEntryOffsets() returns {}.
|
|
|
|
5. PackEntries() - calls Entry.Pack() which figures out the offset and
|
|
size of an entry. The 'current' image offset is passed in, and the function
|
|
returns the offset immediately after the entry being packed. The default
|
|
implementation of Pack() is usually sufficient.
|
|
|
|
Note: for sections, this also checks that the entries do not overlap, nor extend
|
|
outside the section. If the section does not have a defined size, the size is
|
|
set large enough to hold all the entries.
|
|
|
|
6. SetImagePos() - sets the image position of every entry. This is the absolute
|
|
position 'image-pos', as opposed to 'offset' which is relative to the containing
|
|
section. This must be done after all offsets are known, which is why it is quite
|
|
late in the ordering.
|
|
|
|
7. SetCalculatedProperties() - update any calculated properties in the device
|
|
tree. This sets the correct 'offset' and 'size' vaues, for example.
|
|
|
|
8. ProcessEntryContents() - this calls Entry.ProcessContents() on each entry.
|
|
The default implementatoin does nothing. This can be overriden to adjust the
|
|
contents of an entry in some way. For example, it would be possible to create
|
|
an entry containing a hash of the contents of some other entries. At this
|
|
stage the offset and size of entries should not be adjusted unless absolutely
|
|
necessary, since it requires a repack (going back to PackEntries()).
|
|
|
|
9. ResetForPack() - if the ProcessEntryContents() step failed, in that an entry
|
|
has changed its size, then there is no alternative but to go back to step 5 and
|
|
try again, repacking the entries with the updated size. ResetForPack() removes
|
|
the fixed offset/size values added by binman, so that the packing can start from
|
|
scratch.
|
|
|
|
10. WriteSymbols() - write the value of symbols into the U-Boot SPL binary.
|
|
See 'Access to binman entry offsets at run time' below for a description of
|
|
what happens in this stage.
|
|
|
|
11. BuildImage() - builds the image and writes it to a file
|
|
|
|
12. WriteMap() - writes a text file containing a map of the image. This is the
|
|
final step.
|
|
|
|
|
|
External tools
|
|
--------------
|
|
|
|
Binman can make use of external command-line tools to handle processing of
|
|
entry contents or to generate entry contents. These tools are executed using
|
|
the 'tools' module's Run() method. The tools generally must exist on the PATH,
|
|
but the --toolpath option can be used to specify additional search paths to
|
|
use. This option can be specified multiple times to add more than one path.
|
|
|
|
For some compile tools binman will use the versions specified by commonly-used
|
|
environment variables like CC and HOSTCC for the C compiler, based on whether
|
|
the tool's output will be used for the target or for the host machine. If those
|
|
aren't given, it will also try to derive target-specific versions from the
|
|
CROSS_COMPILE environment variable during a cross-compilation.
|
|
|
|
|
|
Code coverage
|
|
-------------
|
|
|
|
Binman is a critical tool and is designed to be very testable. Entry
|
|
implementations target 100% test coverage. Run 'binman test -T' to check this.
|
|
|
|
To enable Python test coverage on Debian-type distributions (e.g. Ubuntu)::
|
|
|
|
$ sudo apt-get install python-coverage python3-coverage python-pytest
|
|
|
|
|
|
Concurrent tests
|
|
----------------
|
|
|
|
Binman tries to run tests concurrently. This means that the tests make use of
|
|
all available CPUs to run.
|
|
|
|
To enable this::
|
|
|
|
$ sudo apt-get install python-subunit python3-subunit
|
|
|
|
Use '-P 1' to disable this. It is automatically disabled when code coverage is
|
|
being used (-T) since they are incompatible.
|
|
|
|
|
|
Debugging tests
|
|
---------------
|
|
|
|
Sometimes when debugging tests it is useful to keep the input and output
|
|
directories so they can be examined later. Use -X or --test-preserve-dirs for
|
|
this.
|
|
|
|
|
|
Running tests on non-x86 architectures
|
|
--------------------------------------
|
|
|
|
Binman's tests have been written under the assumption that they'll be run on a
|
|
x86-like host and there hasn't been an attempt to make them portable yet.
|
|
However, it's possible to run the tests by cross-compiling to x86.
|
|
|
|
To install an x86 cross-compiler on Debian-type distributions (e.g. Ubuntu)::
|
|
|
|
$ sudo apt-get install gcc-x86-64-linux-gnu
|
|
|
|
Then, you can run the tests under cross-compilation::
|
|
|
|
$ CROSS_COMPILE=x86_64-linux-gnu- binman test -T
|
|
|
|
You can also use gcc-i686-linux-gnu similar to the above.
|
|
|
|
|
|
Writing new entries and debugging
|
|
---------------------------------
|
|
|
|
The behaviour of entries is defined by the Entry class. All other entries are
|
|
a subclass of this. An important subclass is Entry_blob which takes binary
|
|
data from a file and places it in the entry. In fact most entry types are
|
|
subclasses of Entry_blob.
|
|
|
|
Each entry type is a separate file in the tools/binman/etype directory. Each
|
|
file contains a class called Entry_<type> where <type> is the entry type.
|
|
New entry types can be supported by adding new files in that directory.
|
|
These will automatically be detected by binman when needed.
|
|
|
|
Entry properties are documented in entry.py. The entry subclasses are free
|
|
to change the values of properties to support special behaviour. For example,
|
|
when Entry_blob loads a file, it sets content_size to the size of the file.
|
|
Entry classes can adjust other entries. For example, an entry that knows
|
|
where other entries should be positioned can set up those entries' offsets
|
|
so they don't need to be set in the binman decription. It can also adjust
|
|
entry contents.
|
|
|
|
Most of the time such essoteric behaviour is not needed, but it can be
|
|
essential for complex images.
|
|
|
|
If you need to specify a particular device-tree compiler to use, you can define
|
|
the DTC environment variable. This can be useful when the system dtc is too
|
|
old.
|
|
|
|
To enable a full backtrace and other debugging features in binman, pass
|
|
BINMAN_DEBUG=1 to your build::
|
|
|
|
make qemu-x86_defconfig
|
|
make BINMAN_DEBUG=1
|
|
|
|
To enable verbose logging from binman, base BINMAN_VERBOSE to your build, which
|
|
adds a -v<level> option to the call to binman::
|
|
|
|
make qemu-x86_defconfig
|
|
make BINMAN_VERBOSE=5
|
|
|
|
|
|
History / Credits
|
|
-----------------
|
|
|
|
Binman takes a lot of inspiration from a Chrome OS tool called
|
|
'cros_bundle_firmware', which I wrote some years ago. That tool was based on
|
|
a reasonably simple and sound design but has expanded greatly over the
|
|
years. In particular its handling of x86 images is convoluted.
|
|
|
|
Quite a few lessons have been learned which are hopefully applied here.
|
|
|
|
|
|
Design notes
|
|
------------
|
|
|
|
On the face of it, a tool to create firmware images should be fairly simple:
|
|
just find all the input binaries and place them at the right place in the
|
|
image. The difficulty comes from the wide variety of input types (simple
|
|
flat binaries containing code, packaged data with various headers), packing
|
|
requirments (alignment, spacing, device boundaries) and other required
|
|
features such as hierarchical images.
|
|
|
|
The design challenge is to make it easy to create simple images, while
|
|
allowing the more complex cases to be supported. For example, for most
|
|
images we don't much care exactly where each binary ends up, so we should
|
|
not have to specify that unnecessarily.
|
|
|
|
New entry types should aim to provide simple usage where possible. If new
|
|
core features are needed, they can be added in the Entry base class.
|
|
|
|
|
|
To do
|
|
-----
|
|
|
|
Some ideas:
|
|
|
|
- Use of-platdata to make the information available to code that is unable
|
|
to use device tree (such as a very small SPL image). For now, limited info is
|
|
available via linker symbols
|
|
- Allow easy building of images by specifying just the board name
|
|
- Support building an image for a board (-b) more completely, with a
|
|
configurable build directory
|
|
- Detect invalid properties in nodes
|
|
- Sort the fdtmap by offset
|
|
- Output temporary files to a different directory
|
|
|
|
--
|
|
Simon Glass <sjg@chromium.org>
|
|
7/7/2016
|