1 .. SPDX-License-Identifier: GPL-2.0+
2 .. Copyright (c) 2016 Google, Inc
7 Firmware often consists of several components which must be packaged together.
8 For example, we may have SPL, U-Boot, a device tree and an environment area
9 grouped together and placed in MMC flash. When the system starts, it must be
10 able to find these pieces.
12 So far U-Boot has not provided a way to handle creating such images in a
13 general way. Each SoC does what it needs to build an image, often packing or
14 concatenating images in the U-Boot build system.
16 Binman aims to provide a mechanism for building images, from simple
17 SPL + U-Boot combinations, to more complex arrangements with many parts.
23 Binman reads your board's device tree and finds a node which describes the
24 required image layout. It uses this to work out what to place where. The
25 output file normally contains the device tree, so it is in principle possible
26 to read an image and extract its constituent parts.
32 So far binman is pretty simple. It supports binary blobs, such as 'u-boot',
33 'spl' and 'fdt'. It supports empty entries (such as setting to 0xff). It can
34 place entries at a fixed location in the image, or fit them together with
35 suitable padding and alignment. It provides a way to process binaries before
36 they are included, by adding a Python plug-in. The device tree is available
37 to U-Boot at run-time so that the images can be interpreted.
39 Binman can update the device tree with the final location of everything when it
40 is done. Entry positions can be provided to U-Boot SPL as run-time symbols,
41 avoiding device-tree code overhead.
43 Binman can also support incorporating filesystems in the image if required.
44 For example x86 platforms may use CBFS in some cases.
46 Binman is intended for use with U-Boot but is designed to be general enough
47 to be useful in other image-packaging situations.
53 Packaging of firmware is quite a different task from building the various
54 parts. In many cases the various binaries which go into the image come from
55 separate build systems. For example, ARM Trusted Firmware is used on ARMv8
56 devices but is not built in the U-Boot tree. If a Linux kernel is included
57 in the firmware image, it is built elsewhere.
59 It is of course possible to add more and more build rules to the U-Boot
60 build system to cover these cases. It can shell out to other Makefiles and
61 build scripts. But it seems better to create a clear divide between building
62 software and packaging it.
64 At present this is handled by manual instructions, different for each board,
65 on how to create images that will boot. By turning these instructions into a
66 standard format, we can support making valid images for any board without
67 manual effort, lots of READMEs, etc.
71 - Each binary can have its own build system and tool chain without creating
72 any dependencies between them
73 - Avoids the need for a single-shot build: individual parts can be updated
74 and brought in as needed
75 - Provides for a standard image description available in the build and at
77 - SoC-specific image-signing tools can be accommodated
78 - Avoids cluttering the U-Boot build system with image-building code
79 - The image description is automatically available at run-time in U-Boot,
80 SPL. It can be made available to other software also
81 - The image description is easily readable (it's a text file in device-tree
82 format) and permits flexible packing of binaries
88 Binman uses the following terms:
90 - image - an output file containing a firmware image
91 - binary - an input binary that goes into the image
97 FIT is U-Boot's official image format. It supports multiple binaries with
98 load / execution addresses, compression. It also supports verification
99 through hashing and RSA signatures.
101 FIT was originally designed to support booting a Linux kernel (with an
102 optional ramdisk) and device tree chosen from various options in the FIT.
103 Now that U-Boot supports configuration via device tree, it is possible to
104 load U-Boot from a FIT, with the device tree chosen by SPL.
106 Binman considers FIT to be one of the binaries it can place in the image.
108 Where possible it is best to put as much as possible in the FIT, with binman
109 used to deal with cases not covered by FIT. Examples include initial
110 execution (since FIT itself does not have an executable header) and dealing
111 with device boundaries, such as the read-only/read-write separation in SPI
114 For U-Boot, binman should not be used to create ad-hoc images in place of
118 Relationship to mkimage
119 -----------------------
121 The mkimage tool provides a means to create a FIT. Traditionally it has
122 needed an image description file: a device tree, like binman, but in a
123 different format. More recently it has started to support a '-f auto' mode
124 which can generate that automatically.
126 More relevant to binman, mkimage also permits creation of many SoC-specific
127 image types. These can be listed by running 'mkimage -T list'. Examples
128 include 'rksd', the Rockchip SD/MMC boot format. The mkimage tool is often
129 called from the U-Boot build system for this reason.
131 Binman considers the output files created by mkimage to be binary blobs
132 which it can place in an image. Binman does not replace the mkimage tool or
133 this purpose. It would be possible in some situations to create a new entry
134 type for the images in mkimage, but this would not add functionality. It
135 seems better to use the mkimage tool to generate binaries and avoid blurring
136 the boundaries between building input files (mkimage) and packaging then
137 into a final image (binman).
140 Example use of binman in U-Boot
141 -------------------------------
143 Binman aims to replace some of the ad-hoc image creation in the U-Boot
146 Consider sunxi. It has the following steps:
148 #. It uses a custom mksunxiboot tool to build an SPL image called
149 sunxi-spl.bin. This should probably move into mkimage.
151 #. It uses mkimage to package U-Boot into a legacy image file (so that it can
152 hold the load and execution address) called u-boot.img.
154 #. It builds a final output image called u-boot-sunxi-with-spl.bin which
155 consists of sunxi-spl.bin, some padding and u-boot.img.
157 Binman is intended to replace the last step. The U-Boot build system builds
158 u-boot.bin and sunxi-spl.bin. Binman can then take over creation of
159 sunxi-spl.bin (by calling mksunxiboot, or hopefully one day mkimage). In any
160 case, it would then create the image from the component parts.
162 This simplifies the U-Boot Makefile somewhat, since various pieces of logic
163 can be replaced by a call to binman.
166 Example use of binman for x86
167 -----------------------------
169 In most cases x86 images have a lot of binary blobs, 'black-box' code
170 provided by Intel which must be run for the platform to work. Typically
171 these blobs are not relocatable and must be placed at fixed areas in the
174 Currently this is handled by ifdtool, which places microcode, FSP, MRC, VGA
175 BIOS, reference code and Intel ME binaries into a u-boot.rom file.
177 Binman is intended to replace all of this, with ifdtool left to handle only
178 the configuration of the Intel-format descriptor.
184 First install prerequisites, e.g::
186 sudo apt-get install python-pyelftools python3-pyelftools lzma-alone \
191 binman build -b <board_name>
193 to build an image for a board. The board name is the same name used when
194 configuring U-Boot (e.g. for sandbox_defconfig the board name is 'sandbox').
195 Binman assumes that the input files for the build are in ../b/<board_name>.
197 Or you can specify this explicitly::
199 binman build -I <build_path>
201 where <build_path> is the build directory containing the output of the U-Boot
204 (Future work will make this more configurable)
206 In either case, binman picks up the device tree file (u-boot.dtb) and looks
207 for its instructions in the 'binman' node.
209 Binman has a few other options which you can see by running 'binman -h'.
212 Enabling binman for a board
213 ---------------------------
215 At present binman is invoked from a rule in the main Makefile. Typically you
216 will have a rule like::
218 ifneq ($(CONFIG_ARCH_<something>),)
219 u-boot-<your_suffix>.bin: <input_file_1> <input_file_2> checkbinman FORCE
220 $(call if_changed,binman)
223 This assumes that u-boot-<your_suffix>.bin is a target, and is the final file
224 that you need to produce. You can make it a target by adding it to INPUTS-y
225 either in the main Makefile or in a config.mk file in your arch subdirectory.
227 Once binman is executed it will pick up its instructions from a device-tree
228 file, typically <soc>-u-boot.dtsi, where <soc> is your CONFIG_SYS_SOC value.
229 You can use other, more specific CONFIG options - see 'Automatic .dtsi
233 Image description format
234 ------------------------
236 The binman node is called 'binman'. An example image description is shown
240 filename = "u-boot-sunxi-with-spl.bin";
243 filename = "spl/sunxi-spl.bin";
246 offset = <CONFIG_SPL_PAD_TO>;
251 This requests binman to create an image file called u-boot-sunxi-with-spl.bin
252 consisting of a specially formatted SPL (spl/sunxi-spl.bin, built by the
253 normal U-Boot Makefile), some 0xff padding, and a U-Boot legacy image. The
254 padding comes from the fact that the second binary is placed at
255 CONFIG_SPL_PAD_TO. If that line were omitted then the U-Boot binary would
256 immediately follow the SPL binary.
258 The binman node describes an image. The sub-nodes describe entries in the
259 image. Each entry represents a region within the overall image. The name of
260 the entry (blob, u-boot) tells binman what to put there. For 'blob' we must
261 provide a filename. For 'u-boot', binman knows that this means 'u-boot.bin'.
263 Entries are normally placed into the image sequentially, one after the other.
264 The image size is the total size of all entries. As you can see, you can
265 specify the start offset of an entry using the 'offset' property.
267 Note that due to a device tree requirement, all entries must have a unique
268 name. If you want to put the same binary in the image multiple times, you can
269 use any unique name, with the 'type' property providing the type.
271 The attributes supported for entries are described below.
274 This sets the offset of an entry within the image or section containing
275 it. The first byte of the image is normally at offset 0. If 'offset' is
276 not provided, binman sets it to the end of the previous region, or the
277 start of the image's entry area (normally 0) if there is no previous
281 This sets the alignment of the entry. The entry offset is adjusted
282 so that the entry starts on an aligned boundary within the containing
283 section or image. For example 'align = <16>' means that the entry will
284 start on a 16-byte boundary. This may mean that padding is added before
285 the entry. The padding is part of the containing section but is not
286 included in the entry, meaning that an empty space may be created before
287 the entry starts. Alignment should be a power of 2. If 'align' is not
288 provided, no alignment is performed.
291 This sets the size of the entry. The contents will be padded out to
292 this size. If this is not provided, it will be set to the size of the
296 Padding before the contents of the entry. Normally this is 0, meaning
297 that the contents start at the beginning of the entry. This can be used
298 to offset the entry contents a little. While this does not affect the
299 contents of the entry within binman itself (the padding is performed
300 only when its parent section is assembled), the end result will be that
301 the entry starts with the padding bytes, so may grow. Defaults to 0.
304 Padding after the contents of the entry. Normally this is 0, meaning
305 that the entry ends at the last byte of content (unless adjusted by
306 other properties). This allows room to be created in the image for
307 this entry to expand later. While this does not affect the contents of
308 the entry within binman itself (the padding is performed only when its
309 parent section is assembled), the end result will be that the entry ends
310 with the padding bytes, so may grow. Defaults to 0.
313 This sets the alignment of the entry size. For example, to ensure
314 that the size of an entry is a multiple of 64 bytes, set this to 64.
315 While this does not affect the contents of the entry within binman
316 itself (the padding is performed only when its parent section is
317 assembled), the end result is that the entry ends with the padding
318 bytes, so may grow. If 'align-size' is not provided, no alignment is
322 This sets the alignment of the end of an entry with respect to the
323 containing section. Some entries require that they end on an alignment
324 boundary, regardless of where they start. This does not move the start
325 of the entry, so the contents of the entry will still start at the
326 beginning. But there may be padding at the end. While this does not
327 affect the contents of the entry within binman itself (the padding is
328 performed only when its parent section is assembled), the end result
329 is that the entry ends with the padding bytes, so may grow.
330 If 'align-end' is not provided, no alignment is performed.
333 For 'blob' types this provides the filename containing the binary to
334 put into the entry. If binman knows about the entry type (like
335 u-boot-bin), then there is no need to specify this.
338 Sets the type of an entry. This defaults to the entry name, but it is
339 possible to use any name, and then add (for example) 'type = "u-boot"'
343 Indicates that the offset of this entry should not be set by placing
344 it immediately after the entry before. Instead, is set by another
345 entry which knows where this entry should go. When this boolean
346 property is present, binman will give an error if another entry does
347 not set the offset (with the GetOffsets() method).
350 This cannot be set on entry (or at least it is ignored if it is), but
351 with the -u option, binman will set it to the absolute image position
352 for each entry. This makes it easy to find out exactly where the entry
353 ended up in the image, regardless of parent sections, etc.
356 Expand the size of this entry to fit available space. This space is only
357 limited by the size of the image/section and the position of the next
361 Sets the compression algortihm to use (for blobs only). See the entry
362 documentation for details.
365 Sets the tag of the message to show if this entry is missing. This is
366 used for external blobs. When they are missing it is helpful to show
367 information about what needs to be fixed. See missing-blob-help for the
368 message for each tag.
370 The attributes supported for images and sections are described below. Several
371 are similar to those for entries.
374 Sets the image size in bytes, for example 'size = <0x100000>' for a
378 This is similar to 'offset' in entries, setting the offset of a section
379 within the image or section containing it. The first byte of the section
380 is normally at offset 0. If 'offset' is not provided, binman sets it to
381 the end of the previous region, or the start of the image's entry area
382 (normally 0) if there is no previous region.
385 This sets the alignment of the image size. For example, to ensure
386 that the image ends on a 512-byte boundary, use 'align-size = <512>'.
387 If 'align-size' is not provided, no alignment is performed.
390 This sets the padding before the image entries. The first entry will
391 be positioned after the padding. This defaults to 0.
394 This sets the padding after the image entries. The padding will be
395 placed after the last entry. This defaults to 0.
398 This specifies the pad byte to use when padding in the image. It
399 defaults to 0. To use 0xff, you would add 'pad-byte = <0xff>'.
402 This specifies the image filename. It defaults to 'image.bin'.
405 This causes binman to reorder the entries as needed to make sure they
406 are in increasing positional order. This can be used when your entry
407 order may not match the positional order. A common situation is where
408 the 'offset' properties are set by CONFIG options, so their ordering is
411 This is a boolean property so needs no value. To enable it, add a
412 line 'sort-by-offset;' to your description.
415 Normally only a single image is generated. To create more than one
416 image, put this property in the binman node. For example, this will
417 create image1.bin containing u-boot.bin, and image2.bin containing
418 both spl/u-boot-spl.bin and u-boot.bin::
436 For x86 machines the ROM offsets start just before 4GB and extend
437 up so that the image finished at the 4GB boundary. This boolean
438 option can be enabled to support this. The image size must be
439 provided so that binman knows when the image should start. For an
440 8MB ROM, the offset of the first entry would be 0xfff80000 with
441 this option, instead of 0 without this option.
444 This property specifies the entry offset of the first entry.
446 For PowerPC mpc85xx based CPU, CONFIG_SYS_TEXT_BASE is the entry
447 offset of the first entry. It can be 0xeff40000 or 0xfff40000 for
448 nor flash boot, 0x201000 for sd boot etc.
450 'end-at-4gb' property is not applicable where CONFIG_SYS_TEXT_BASE +
453 Examples of the above options can be found in the tests. See the
454 tools/binman/test directory.
456 It is possible to have the same binary appear multiple times in the image,
457 either by using a unit number suffix (u-boot@0, u-boot@1) or by using a
458 different name for each and specifying the type with the 'type' attribute.
461 Sections and hierachical images
462 -------------------------------
464 Sometimes it is convenient to split an image into several pieces, each of which
465 contains its own set of binaries. An example is a flash device where part of
466 the image is read-only and part is read-write. We can set up sections for each
467 of these, and place binaries in them independently. The image is still produced
468 as a single output file.
470 This feature provides a way of creating hierarchical images. For example here
471 is an example image with two copies of U-Boot. One is read-only (ro), intended
472 to be written only in the factory. Another is read-write (rw), so that it can be
473 upgraded in the field. The sizes are fixed so that the ro/rw boundary is known
474 and can be programmed::
492 This image could be placed into a SPI flash chip, with the protection boundary
495 A few special properties are provided for sections:
498 Indicates that this section is read-only. This has no impact on binman's
499 operation, but his property can be read at run time.
502 This string is prepended to all the names of the binaries in the
503 section. In the example above, the 'u-boot' binaries which actually be
504 renamed to 'ro-u-boot' and 'rw-u-boot'. This can be useful to
505 distinguish binaries with otherwise identical names.
511 Image nodes act like sections but also have a few extra properties:
514 Output filename for the image. This defaults to image.bin (or in the
515 case of multiple images <nodename>.bin where <nodename> is the name of
519 Create an image that can be repacked. With this option it is possible
520 to change anything in the image after it is created, including updating
521 the position and size of image components. By default this is not
522 permitted since it is not possibly to know whether this might violate a
523 constraint in the image description. For example, if a section has to
524 increase in size to hold a larger binary, that might cause the section
525 to fall out of its allow region (e.g. read-only portion of flash).
527 Adding this property causes the original offset and size values in the
528 image description to be stored in the FDT and fdtmap.
534 For details on the various entry types supported by binman and how to use them,
535 see README.entries. This is generated from the source code using:
537 binman entry-docs >tools/binman/README.entries
543 It is possible to list the entries in an existing firmware image created by
544 binman, provided that there is an 'fdtmap' entry in the image. For example::
546 $ binman ls -i image.bin
547 Name Image-pos Size Entry-type Offset Uncomp-size
548 ----------------------------------------------------------------------
549 main-section c00 section 0
551 section 5fc section 4
553 u-boot 138 4 u-boot 38
554 u-boot-dtb 180 108 u-boot-dtb 80 3b5
555 u-boot-dtb 500 1ff u-boot-dtb 400 3b5
556 fdtmap 6fc 381 fdtmap 6fc
557 image-header bf8 8 image-header bf8
559 This shows the hierarchy of the image, the position, size and type of each
560 entry, the offset of each entry within its parent and the uncompressed size if
561 the entry is compressed.
563 It is also possible to list just some files in an image, e.g.::
565 $ binman ls -i image.bin section/cbfs
566 Name Image-pos Size Entry-type Offset Uncomp-size
567 --------------------------------------------------------------------
569 u-boot 138 4 u-boot 38
570 u-boot-dtb 180 108 u-boot-dtb 80 3b5
574 $ binman ls -i image.bin "*cb*" "*head*"
575 Name Image-pos Size Entry-type Offset Uncomp-size
576 ----------------------------------------------------------------------
578 u-boot 138 4 u-boot 38
579 u-boot-dtb 180 108 u-boot-dtb 80 3b5
580 image-header bf8 8 image-header bf8
583 Extracting files from images
584 ----------------------------
586 You can extract files from an existing firmware image created by binman,
587 provided that there is an 'fdtmap' entry in the image. For example::
589 $ binman extract -i image.bin section/cbfs/u-boot
591 which will write the uncompressed contents of that entry to the file 'u-boot' in
592 the current directory. You can also extract to a particular file, in this case
595 $ binman extract -i image.bin section/cbfs/u-boot -f u-boot.bin
597 It is possible to extract all files into a destination directory, which will
598 put files in subdirectories matching the entry hierarchy::
600 $ binman extract -i image.bin -O outdir
602 or just a selection::
604 $ binman extract -i image.bin "*u-boot*" -O outdir
607 Replacing files in an image
608 ---------------------------
610 You can replace files in an existing firmware image created by binman, provided
611 that there is an 'fdtmap' entry in the image. For example:
613 $ binman replace -i image.bin section/cbfs/u-boot
615 which will write the contents of the file 'u-boot' from the current directory
616 to the that entry, compressing if necessary. If the entry size changes, you must
617 add the 'allow-repack' property to the original image before generating it (see
618 above), otherwise you will get an error.
620 You can also use a particular file, in this case u-boot.bin::
622 $ binman replace -i image.bin section/cbfs/u-boot -f u-boot.bin
624 It is possible to replace all files from a source directory which uses the same
625 hierarchy as the entries::
627 $ binman replace -i image.bin -I indir
629 Files that are missing will generate a warning.
631 You can also replace just a selection of entries::
633 $ binman replace -i image.bin "*u-boot*" -I indir
639 Binman normally operates silently unless there is an error, in which case it
640 just displays the error. The -D/--debug option can be used to create a full
641 backtrace when errors occur. You can use BINMAN_DEBUG=1 when building to select
644 Internally binman logs some output while it is running. This can be displayed
645 by increasing the -v/--verbosity from the default of 1:
649 2: notices (important messages)
650 3: info about major operations
651 4: detailed information about each operation
652 5: debug (all output)
654 You can use BINMAN_VERBOSE=5 (for example) when building to select this.
659 It is possible to ask binman to hash the contents of an entry and write that
660 value back to the device-tree node. For example::
670 Here, a new 'value' property will be written to the 'hash' node containing
671 the hash of the 'u-boot' entry. Only SHA256 is supported at present. Whole
672 sections can be hased if desired, by adding the 'hash' node to the section.
674 The has value can be chcked at runtime by hashing the data actually read and
675 comparing this has to the value in the device tree.
678 Order of image creation
679 -----------------------
681 Image creation proceeds in the following order, for each entry in the image.
683 1. AddMissingProperties() - binman can add calculated values to the device
684 tree as part of its processing, for example the offset and size of each
685 entry. This method adds any properties associated with this, expanding the
686 device tree as needed. These properties can have placeholder values which are
687 set later by SetCalculatedProperties(). By that stage the size of sections
688 cannot be changed (since it would cause the images to need to be repacked),
689 but the correct values can be inserted.
691 2. ProcessFdt() - process the device tree information as required by the
692 particular entry. This may involve adding or deleting properties. If the
693 processing is complete, this method should return True. If the processing
694 cannot complete because it needs the ProcessFdt() method of another entry to
695 run first, this method should return False, in which case it will be called
698 3. GetEntryContents() - the contents of each entry are obtained, normally by
699 reading from a file. This calls the Entry.ObtainContents() to read the
700 contents. The default version of Entry.ObtainContents() calls
701 Entry.GetDefaultFilename() and then reads that file. So a common mechanism
702 to select a file to read is to override that function in the subclass. The
703 functions must return True when they have read the contents. Binman will
704 retry calling the functions a few times if False is returned, allowing
705 dependencies between the contents of different entries.
707 4. GetEntryOffsets() - calls Entry.GetOffsets() for each entry. This can
708 return a dict containing entries that need updating. The key should be the
709 entry name and the value is a tuple (offset, size). This allows an entry to
710 provide the offset and size for other entries. The default implementation
711 of GetEntryOffsets() returns {}.
713 5. PackEntries() - calls Entry.Pack() which figures out the offset and
714 size of an entry. The 'current' image offset is passed in, and the function
715 returns the offset immediately after the entry being packed. The default
716 implementation of Pack() is usually sufficient.
718 Note: for sections, this also checks that the entries do not overlap, nor extend
719 outside the section. If the section does not have a defined size, the size is
720 set large enough to hold all the entries.
722 6. SetImagePos() - sets the image position of every entry. This is the absolute
723 position 'image-pos', as opposed to 'offset' which is relative to the containing
724 section. This must be done after all offsets are known, which is why it is quite
725 late in the ordering.
727 7. SetCalculatedProperties() - update any calculated properties in the device
728 tree. This sets the correct 'offset' and 'size' vaues, for example.
730 8. ProcessEntryContents() - this calls Entry.ProcessContents() on each entry.
731 The default implementatoin does nothing. This can be overriden to adjust the
732 contents of an entry in some way. For example, it would be possible to create
733 an entry containing a hash of the contents of some other entries. At this
734 stage the offset and size of entries should not be adjusted unless absolutely
735 necessary, since it requires a repack (going back to PackEntries()).
737 9. ResetForPack() - if the ProcessEntryContents() step failed, in that an entry
738 has changed its size, then there is no alternative but to go back to step 5 and
739 try again, repacking the entries with the updated size. ResetForPack() removes
740 the fixed offset/size values added by binman, so that the packing can start from
743 10. WriteSymbols() - write the value of symbols into the U-Boot SPL binary.
744 See 'Access to binman entry offsets at run time' below for a description of
745 what happens in this stage.
747 11. BuildImage() - builds the image and writes it to a file
749 12. WriteMap() - writes a text file containing a map of the image. This is the
753 Automatic .dtsi inclusion
754 -------------------------
756 It is sometimes inconvenient to add a 'binman' node to the .dts file for each
757 board. This can be done by using #include to bring in a common file. Another
758 approach supported by the U-Boot build system is to automatically include
759 a common header. You can then put the binman node (and anything else that is
760 specific to U-Boot, such as u-boot,dm-pre-reloc properies) in that header
763 Binman will search for the following files in arch/<arch>/dts::
765 <dts>-u-boot.dtsi where <dts> is the base name of the .dts file
766 <CONFIG_SYS_SOC>-u-boot.dtsi
767 <CONFIG_SYS_CPU>-u-boot.dtsi
768 <CONFIG_SYS_VENDOR>-u-boot.dtsi
771 U-Boot will only use the first one that it finds. If you need to include a
772 more general file you can do that from the more specific file using #include.
773 If you are having trouble figuring out what is going on, you can uncomment
774 the 'warning' line in scripts/Makefile.lib to see what it has found::
776 # Uncomment for debugging
777 # This shows all the files that were considered and the one that we chose.
778 # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
781 Access to binman entry offsets at run time (symbols)
782 ----------------------------------------------------
784 Binman assembles images and determines where each entry is placed in the image.
785 This information may be useful to U-Boot at run time. For example, in SPL it
786 is useful to be able to find the location of U-Boot so that it can be executed
787 when SPL is finished.
789 Binman allows you to declare symbols in the SPL image which are filled in
790 with their correct values during the build. For example::
792 binman_sym_declare(ulong, u_boot_any, image_pos);
794 declares a ulong value which will be assigned to the image-pos of any U-Boot
795 image (u-boot.bin, u-boot.img, u-boot-nodtb.bin) that is present in the image.
796 You can access this value with something like::
798 ulong u_boot_offset = binman_sym(ulong, u_boot_any, image_pos);
800 Thus u_boot_offset will be set to the image-pos of U-Boot in memory, assuming
801 that the whole image has been loaded, or is available in flash. You can then
802 jump to that address to start U-Boot.
804 At present this feature is only supported in SPL and TPL. In principle it is
805 possible to fill in such symbols in U-Boot proper, as well, but a future C
806 library is planned for this instead, to read from the device tree.
808 As well as image-pos, it is possible to read the size of an entry and its
809 offset (which is the start position of the entry within its parent).
811 A small technical note: Binman automatically adds the base address of the image
812 (i.e. __image_copy_start) to the value of the image-pos symbol, so that when the
813 image is loaded to its linked address, the value will be correct and actually
814 point into the image.
816 For example, say SPL is at the start of the image and linked to start at address
817 80108000. If U-Boot's image-pos is 0x8000 then binman will write an image-pos
818 for U-Boot of 80110000 into the SPL binary, since it assumes the image is loaded
819 to 80108000, with SPL at 80108000 and U-Boot at 80110000.
821 For x86 devices (with the end-at-4gb property) this base address is not added
822 since it is assumed that images are XIP and the offsets already include the
826 Access to binman entry offsets at run time (fdt)
827 ------------------------------------------------
829 Binman can update the U-Boot FDT to include the final position and size of
830 each entry in the images it processes. The option to enable this is -u and it
831 causes binman to make sure that the 'offset', 'image-pos' and 'size' properties
832 are set correctly for every entry. Since it is not necessary to specify these in
833 the image definition, binman calculates the final values and writes these to
834 the device tree. These can be used by U-Boot at run-time to find the location
837 Alternatively, an FDT map entry can be used to add a special FDT containing
838 just the information about the image. This is preceded by a magic string so can
839 be located anywhere in the image. An image header (typically at the start or end
840 of the image) can be used to point to the FDT map. See fdtmap and image-header
841 entries for more information.
847 Binman automatically replaces 'u-boot' with an expanded version of that, i.e.
848 'u-boot-expanded'. This means that when you write::
856 type = "u-boot-expanded';
859 which in turn expands to::
871 U-Boot's various phase binaries actually comprise two or three pieces.
872 For example, u-boot.bin has the executable followed by a devicetree.
874 With binman we want to be able to update that devicetree with full image
875 information so that it is accessible to the executable. This is tricky
876 if it is not clear where the devicetree starts.
878 The above feature ensures that the devicetree is clearly separated from the
879 U-Boot executable and can be updated separately by binman as needed. It can be
880 disabled with the --no-expanded flag if required.
882 The same applies for u-boot-spl and u-boot-spl. In those cases, the expansion
883 includes the BSS padding, so for example::
892 type = "u-boot-expanded';
895 which in turn expands to::
911 Of course we should not expand SPL if it has no devicetree. Also if the BSS
912 padding is not needed (because BSS is in RAM as with CONFIG_SPL_SEPARATE_BSS),
913 the 'u-boot-spl-bss-pad' subnode should not be created. The use of the expaned
914 entry type is controlled by the UseExpanded() method. In the SPL case it checks
915 the 'spl-dtb' entry arg, which is 'y' or '1' if SPL has a devicetree.
917 For the BSS case, a 'spl-bss-pad' entry arg controls whether it is present. All
918 entry args are provided by the U-Boot Makefile.
924 Binman support compression for 'blob' entries (those of type 'blob' and
925 derivatives). To enable this for an entry, add a 'compress' property::
928 filename = "datafile";
932 The entry will then contain the compressed data, using the 'lz4' compression
933 algorithm. Currently this is the only one that is supported. The uncompressed
934 size is written to the node in an 'uncomp-size' property, if -u is used.
936 Compression is also supported for sections. In that case the entire section is
937 compressed in one block, including all its contents. This means that accessing
938 an entry from the section required decompressing the entire section. Also, the
939 size of a section indicates the space that it consumes in its parent section
940 (and typically the image). With compression, the section may contain more data,
941 and the uncomp-size property indicates that, as above. The contents of the
942 section is compressed first, before any padding is added. This ensures that the
943 padding itself is not compressed, which would be a waste of time.
949 The -m option causes binman to output a .map file for each image that it
950 generates. This shows the offset and size of each entry. For example::
953 00000000 00000028 main-section
954 00000000 00000010 section@0
955 00000000 00000004 u-boot
956 00000010 00000010 section@1
957 00000000 00000004 u-boot
959 This shows a hierarchical image with two sections, each with a single entry. The
960 offsets of the sections are absolute hex byte offsets within the image. The
961 offsets of the entries are relative to their respective sections. The size of
962 each entry is also shown, in bytes (hex). The indentation shows the entries
963 nested inside their sections.
966 Passing command-line arguments to entries
967 -----------------------------------------
969 Sometimes it is useful to pass binman the value of an entry property from the
970 command line. For example some entries need access to files and it is not
971 always convenient to put these filenames in the image definition (device tree).
973 The-a option supports this::
979 <prop> is the property to set
980 <value> is the value to set it to
982 Not all properties can be provided this way. Only some entries support it,
983 typically for filenames.
989 Binman can make use of external command-line tools to handle processing of
990 entry contents or to generate entry contents. These tools are executed using
991 the 'tools' module's Run() method. The tools generally must exist on the PATH,
992 but the --toolpath option can be used to specify additional search paths to
993 use. This option can be specified multiple times to add more than one path.
995 For some compile tools binman will use the versions specified by commonly-used
996 environment variables like CC and HOSTCC for the C compiler, based on whether
997 the tool's output will be used for the target or for the host machine. If those
998 aren't given, it will also try to derive target-specific versions from the
999 CROSS_COMPILE environment variable during a cross-compilation.
1005 Binman is a critical tool and is designed to be very testable. Entry
1006 implementations target 100% test coverage. Run 'binman test -T' to check this.
1008 To enable Python test coverage on Debian-type distributions (e.g. Ubuntu)::
1010 $ sudo apt-get install python-coverage python3-coverage python-pytest
1016 Binman tries to run tests concurrently. This means that the tests make use of
1017 all available CPUs to run.
1021 $ sudo apt-get install python-subunit python3-subunit
1023 Use '-P 1' to disable this. It is automatically disabled when code coverage is
1024 being used (-T) since they are incompatible.
1030 Sometimes when debugging tests it is useful to keep the input and output
1031 directories so they can be examined later. Use -X or --test-preserve-dirs for
1035 Running tests on non-x86 architectures
1036 --------------------------------------
1038 Binman's tests have been written under the assumption that they'll be run on a
1039 x86-like host and there hasn't been an attempt to make them portable yet.
1040 However, it's possible to run the tests by cross-compiling to x86.
1042 To install an x86 cross-compiler on Debian-type distributions (e.g. Ubuntu)::
1044 $ sudo apt-get install gcc-x86-64-linux-gnu
1046 Then, you can run the tests under cross-compilation::
1048 $ CROSS_COMPILE=x86_64-linux-gnu- binman test -T
1050 You can also use gcc-i686-linux-gnu similar to the above.
1053 Advanced Features / Technical docs
1054 ----------------------------------
1056 The behaviour of entries is defined by the Entry class. All other entries are
1057 a subclass of this. An important subclass is Entry_blob which takes binary
1058 data from a file and places it in the entry. In fact most entry types are
1059 subclasses of Entry_blob.
1061 Each entry type is a separate file in the tools/binman/etype directory. Each
1062 file contains a class called Entry_<type> where <type> is the entry type.
1063 New entry types can be supported by adding new files in that directory.
1064 These will automatically be detected by binman when needed.
1066 Entry properties are documented in entry.py. The entry subclasses are free
1067 to change the values of properties to support special behaviour. For example,
1068 when Entry_blob loads a file, it sets content_size to the size of the file.
1069 Entry classes can adjust other entries. For example, an entry that knows
1070 where other entries should be positioned can set up those entries' offsets
1071 so they don't need to be set in the binman decription. It can also adjust
1074 Most of the time such essoteric behaviour is not needed, but it can be
1075 essential for complex images.
1077 If you need to specify a particular device-tree compiler to use, you can define
1078 the DTC environment variable. This can be useful when the system dtc is too
1081 To enable a full backtrace and other debugging features in binman, pass
1082 BINMAN_DEBUG=1 to your build::
1084 make qemu-x86_defconfig
1087 To enable verbose logging from binman, base BINMAN_VERBOSE to your build, which
1088 adds a -v<level> option to the call to binman::
1090 make qemu-x86_defconfig
1091 make BINMAN_VERBOSE=5
1097 Binman takes a lot of inspiration from a Chrome OS tool called
1098 'cros_bundle_firmware', which I wrote some years ago. That tool was based on
1099 a reasonably simple and sound design but has expanded greatly over the
1100 years. In particular its handling of x86 images is convoluted.
1102 Quite a few lessons have been learned which are hopefully applied here.
1108 On the face of it, a tool to create firmware images should be fairly simple:
1109 just find all the input binaries and place them at the right place in the
1110 image. The difficulty comes from the wide variety of input types (simple
1111 flat binaries containing code, packaged data with various headers), packing
1112 requirments (alignment, spacing, device boundaries) and other required
1113 features such as hierarchical images.
1115 The design challenge is to make it easy to create simple images, while
1116 allowing the more complex cases to be supported. For example, for most
1117 images we don't much care exactly where each binary ends up, so we should
1118 not have to specify that unnecessarily.
1120 New entry types should aim to provide simple usage where possible. If new
1121 core features are needed, they can be added in the Entry base class.
1129 - Use of-platdata to make the information available to code that is unable
1130 to use device tree (such as a very small SPL image)
1131 - Allow easy building of images by specifying just the board name
1132 - Support building an image for a board (-b) more completely, with a
1133 configurable build directory
1134 - Detect invalid properties in nodes
1135 - Sort the fdtmap by offset
1136 - Output temporary files to a different directory
1139 Simon Glass <sjg@chromium.org>