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.
70 - Each binary can have its own build system and tool chain without creating
71 any dependencies between them
72 - Avoids the need for a single-shot build: individual parts can be updated
73 and brought in as needed
74 - Provides for a standard image description available in the build and at
76 - SoC-specific image-signing tools can be accommodated
77 - Avoids cluttering the U-Boot build system with image-building code
78 - The image description is automatically available at run-time in U-Boot,
79 SPL. It can be made available to other software also
80 - The image description is easily readable (it's a text file in device-tree
81 format) and permits flexible packing of binaries
87 Binman uses the following terms:
89 - image - an output file containing a firmware image
90 - binary - an input binary that goes into the image
96 FIT is U-Boot's official image format. It supports multiple binaries with
97 load / execution addresses, compression. It also supports verification
98 through hashing and RSA signatures.
100 FIT was originally designed to support booting a Linux kernel (with an
101 optional ramdisk) and device tree chosen from various options in the FIT.
102 Now that U-Boot supports configuration via device tree, it is possible to
103 load U-Boot from a FIT, with the device tree chosen by SPL.
105 Binman considers FIT to be one of the binaries it can place in the image.
107 Where possible it is best to put as much as possible in the FIT, with binman
108 used to deal with cases not covered by FIT. Examples include initial
109 execution (since FIT itself does not have an executable header) and dealing
110 with device boundaries, such as the read-only/read-write separation in SPI
113 For U-Boot, binman should not be used to create ad-hoc images in place of
117 Relationship to mkimage
118 -----------------------
120 The mkimage tool provides a means to create a FIT. Traditionally it has
121 needed an image description file: a device tree, like binman, but in a
122 different format. More recently it has started to support a '-f auto' mode
123 which can generate that automatically.
125 More relevant to binman, mkimage also permits creation of many SoC-specific
126 image types. These can be listed by running 'mkimage -T list'. Examples
127 include 'rksd', the Rockchip SD/MMC boot format. The mkimage tool is often
128 called from the U-Boot build system for this reason.
130 Binman considers the output files created by mkimage to be binary blobs
131 which it can place in an image. Binman does not replace the mkimage tool or
132 this purpose. It would be possible in some situations to create a new entry
133 type for the images in mkimage, but this would not add functionality. It
134 seems better to use the mkimage tool to generate binaries and avoid blurring
135 the boundaries between building input files (mkimage) and packaging then
136 into a final image (binman).
139 Example use of binman in U-Boot
140 -------------------------------
142 Binman aims to replace some of the ad-hoc image creation in the U-Boot
145 Consider sunxi. It has the following steps:
147 1. It uses a custom mksunxiboot tool to build an SPL image called
148 sunxi-spl.bin. This should probably move into mkimage.
150 2. It uses mkimage to package U-Boot into a legacy image file (so that it can
151 hold the load and execution address) called u-boot.img.
153 3. It builds a final output image called u-boot-sunxi-with-spl.bin which
154 consists of sunxi-spl.bin, some padding and u-boot.img.
156 Binman is intended to replace the last step. The U-Boot build system builds
157 u-boot.bin and sunxi-spl.bin. Binman can then take over creation of
158 sunxi-spl.bin (by calling mksunxiboot, or hopefully one day mkimage). In any
159 case, it would then create the image from the component parts.
161 This simplifies the U-Boot Makefile somewhat, since various pieces of logic
162 can be replaced by a call to binman.
165 Example use of binman for x86
166 -----------------------------
168 In most cases x86 images have a lot of binary blobs, 'black-box' code
169 provided by Intel which must be run for the platform to work. Typically
170 these blobs are not relocatable and must be placed at fixed areas in the
173 Currently this is handled by ifdtool, which places microcode, FSP, MRC, VGA
174 BIOS, reference code and Intel ME binaries into a u-boot.rom file.
176 Binman is intended to replace all of this, with ifdtool left to handle only
177 the configuration of the Intel-format descriptor.
183 First install prerequisites, e.g.
185 sudo apt-get install python-pyelftools python3-pyelftools lzma-alone \
190 binman build -b <board_name>
192 to build an image for a board. The board name is the same name used when
193 configuring U-Boot (e.g. for sandbox_defconfig the board name is 'sandbox').
194 Binman assumes that the input files for the build are in ../b/<board_name>.
196 Or you can specify this explicitly:
198 binman build -I <build_path>
200 where <build_path> is the build directory containing the output of the U-Boot
203 (Future work will make this more configurable)
205 In either case, binman picks up the device tree file (u-boot.dtb) and looks
206 for its instructions in the 'binman' node.
208 Binman has a few other options which you can see by running 'binman -h'.
211 Enabling binman for a board
212 ---------------------------
214 At present binman is invoked from a rule in the main Makefile. Typically you
215 will have a rule like:
217 ifneq ($(CONFIG_ARCH_<something>),)
218 u-boot-<your_suffix>.bin: <input_file_1> <input_file_2> checkbinman FORCE
219 $(call if_changed,binman)
222 This assumes that u-boot-<your_suffix>.bin is a target, and is the final file
223 that you need to produce. You can make it a target by adding it to INPUTS-y
224 either in the main Makefile or in a config.mk file in your arch subdirectory.
226 Once binman is executed it will pick up its instructions from a device-tree
227 file, typically <soc>-u-boot.dtsi, where <soc> is your CONFIG_SYS_SOC value.
228 You can use other, more specific CONFIG options - see 'Automatic .dtsi
232 Image description format
233 ------------------------
235 The binman node is called 'binman'. An example image description is shown
239 filename = "u-boot-sunxi-with-spl.bin";
242 filename = "spl/sunxi-spl.bin";
245 offset = <CONFIG_SPL_PAD_TO>;
250 This requests binman to create an image file called u-boot-sunxi-with-spl.bin
251 consisting of a specially formatted SPL (spl/sunxi-spl.bin, built by the
252 normal U-Boot Makefile), some 0xff padding, and a U-Boot legacy image. The
253 padding comes from the fact that the second binary is placed at
254 CONFIG_SPL_PAD_TO. If that line were omitted then the U-Boot binary would
255 immediately follow the SPL binary.
257 The binman node describes an image. The sub-nodes describe entries in the
258 image. Each entry represents a region within the overall image. The name of
259 the entry (blob, u-boot) tells binman what to put there. For 'blob' we must
260 provide a filename. For 'u-boot', binman knows that this means 'u-boot.bin'.
262 Entries are normally placed into the image sequentially, one after the other.
263 The image size is the total size of all entries. As you can see, you can
264 specify the start offset of an entry using the 'offset' property.
266 Note that due to a device tree requirement, all entries must have a unique
267 name. If you want to put the same binary in the image multiple times, you can
268 use any unique name, with the 'type' property providing the type.
270 The attributes supported for entries are described below.
273 This sets the offset of an entry within the image or section containing
274 it. The first byte of the image is normally at offset 0. If 'offset' is
275 not provided, binman sets it to the end of the previous region, or the
276 start of the image's entry area (normally 0) if there is no previous
280 This sets the alignment of the entry. The entry offset is adjusted
281 so that the entry starts on an aligned boundary within the image. For
282 example 'align = <16>' means that the entry will start on a 16-byte
283 boundary. Alignment shold be a power of 2. If 'align' is not
284 provided, no alignment is performed.
287 This sets the size of the entry. The contents will be padded out to
288 this size. If this is not provided, it will be set to the size of the
292 Padding before the contents of the entry. Normally this is 0, meaning
293 that the contents start at the beginning of the entry. This can be
294 offset the entry contents a little. Defaults to 0.
297 Padding after the contents of the entry. Normally this is 0, meaning
298 that the entry ends at the last byte of content (unless adjusted by
299 other properties). This allows room to be created in the image for
300 this entry to expand later. Defaults to 0.
303 This sets the alignment of the entry size. For example, to ensure
304 that the size of an entry is a multiple of 64 bytes, set this to 64.
305 If 'align-size' is not provided, no alignment is performed.
308 This sets the alignment of the end of an entry. Some entries require
309 that they end on an alignment boundary, regardless of where they
310 start. This does not move the start of the entry, so the contents of
311 the entry will still start at the beginning. But there may be padding
312 at the end. If 'align-end' is not provided, no alignment is performed.
315 For 'blob' types this provides the filename containing the binary to
316 put into the entry. If binman knows about the entry type (like
317 u-boot-bin), then there is no need to specify this.
320 Sets the type of an entry. This defaults to the entry name, but it is
321 possible to use any name, and then add (for example) 'type = "u-boot"'
325 Indicates that the offset of this entry should not be set by placing
326 it immediately after the entry before. Instead, is set by another
327 entry which knows where this entry should go. When this boolean
328 property is present, binman will give an error if another entry does
329 not set the offset (with the GetOffsets() method).
332 This cannot be set on entry (or at least it is ignored if it is), but
333 with the -u option, binman will set it to the absolute image position
334 for each entry. This makes it easy to find out exactly where the entry
335 ended up in the image, regardless of parent sections, etc.
338 Expand the size of this entry to fit available space. This space is only
339 limited by the size of the image/section and the position of the next
343 Sets the compression algortihm to use (for blobs only). See the entry
344 documentation for details.
347 Sets the tag of the message to show if this entry is missing. This is
348 used for external blobs. When they are missing it is helpful to show
349 information about what needs to be fixed. See missing-blob-help for the
350 message for each tag.
352 The attributes supported for images and sections are described below. Several
353 are similar to those for entries.
356 Sets the image size in bytes, for example 'size = <0x100000>' for a
360 This is similar to 'offset' in entries, setting the offset of a section
361 within the image or section containing it. The first byte of the section
362 is normally at offset 0. If 'offset' is not provided, binman sets it to
363 the end of the previous region, or the start of the image's entry area
364 (normally 0) if there is no previous region.
367 This sets the alignment of the image size. For example, to ensure
368 that the image ends on a 512-byte boundary, use 'align-size = <512>'.
369 If 'align-size' is not provided, no alignment is performed.
372 This sets the padding before the image entries. The first entry will
373 be positioned after the padding. This defaults to 0.
376 This sets the padding after the image entries. The padding will be
377 placed after the last entry. This defaults to 0.
380 This specifies the pad byte to use when padding in the image. It
381 defaults to 0. To use 0xff, you would add 'pad-byte = <0xff>'.
384 This specifies the image filename. It defaults to 'image.bin'.
387 This causes binman to reorder the entries as needed to make sure they
388 are in increasing positional order. This can be used when your entry
389 order may not match the positional order. A common situation is where
390 the 'offset' properties are set by CONFIG options, so their ordering is
393 This is a boolean property so needs no value. To enable it, add a
394 line 'sort-by-offset;' to your description.
397 Normally only a single image is generated. To create more than one
398 image, put this property in the binman node. For example, this will
399 create image1.bin containing u-boot.bin, and image2.bin containing
400 both spl/u-boot-spl.bin and u-boot.bin:
418 For x86 machines the ROM offsets start just before 4GB and extend
419 up so that the image finished at the 4GB boundary. This boolean
420 option can be enabled to support this. The image size must be
421 provided so that binman knows when the image should start. For an
422 8MB ROM, the offset of the first entry would be 0xfff80000 with
423 this option, instead of 0 without this option.
426 This property specifies the entry offset of the first entry.
428 For PowerPC mpc85xx based CPU, CONFIG_SYS_TEXT_BASE is the entry
429 offset of the first entry. It can be 0xeff40000 or 0xfff40000 for
430 nor flash boot, 0x201000 for sd boot etc.
432 'end-at-4gb' property is not applicable where CONFIG_SYS_TEXT_BASE +
435 Examples of the above options can be found in the tests. See the
436 tools/binman/test directory.
438 It is possible to have the same binary appear multiple times in the image,
439 either by using a unit number suffix (u-boot@0, u-boot@1) or by using a
440 different name for each and specifying the type with the 'type' attribute.
443 Sections and hierachical images
444 -------------------------------
446 Sometimes it is convenient to split an image into several pieces, each of which
447 contains its own set of binaries. An example is a flash device where part of
448 the image is read-only and part is read-write. We can set up sections for each
449 of these, and place binaries in them independently. The image is still produced
450 as a single output file.
452 This feature provides a way of creating hierarchical images. For example here
453 is an example image with two copies of U-Boot. One is read-only (ro), intended
454 to be written only in the factory. Another is read-write (rw), so that it can be
455 upgraded in the field. The sizes are fixed so that the ro/rw boundary is known
456 and can be programmed:
474 This image could be placed into a SPI flash chip, with the protection boundary
477 A few special properties are provided for sections:
480 Indicates that this section is read-only. This has no impact on binman's
481 operation, but his property can be read at run time.
484 This string is prepended to all the names of the binaries in the
485 section. In the example above, the 'u-boot' binaries which actually be
486 renamed to 'ro-u-boot' and 'rw-u-boot'. This can be useful to
487 distinguish binaries with otherwise identical names.
493 Image nodes act like sections but also have a few extra properties:
496 Output filename for the image. This defaults to image.bin (or in the
497 case of multiple images <nodename>.bin where <nodename> is the name of
501 Create an image that can be repacked. With this option it is possible
502 to change anything in the image after it is created, including updating
503 the position and size of image components. By default this is not
504 permitted since it is not possibly to know whether this might violate a
505 constraint in the image description. For example, if a section has to
506 increase in size to hold a larger binary, that might cause the section
507 to fall out of its allow region (e.g. read-only portion of flash).
509 Adding this property causes the original offset and size values in the
510 image description to be stored in the FDT and fdtmap.
516 For details on the various entry types supported by binman and how to use them,
517 see README.entries. This is generated from the source code using:
519 binman entry-docs >tools/binman/README.entries
525 It is possible to list the entries in an existing firmware image created by
526 binman, provided that there is an 'fdtmap' entry in the image. For example:
528 $ binman ls -i image.bin
529 Name Image-pos Size Entry-type Offset Uncomp-size
530 ----------------------------------------------------------------------
531 main-section c00 section 0
533 section 5fc section 4
535 u-boot 138 4 u-boot 38
536 u-boot-dtb 180 108 u-boot-dtb 80 3b5
537 u-boot-dtb 500 1ff u-boot-dtb 400 3b5
538 fdtmap 6fc 381 fdtmap 6fc
539 image-header bf8 8 image-header bf8
541 This shows the hierarchy of the image, the position, size and type of each
542 entry, the offset of each entry within its parent and the uncompressed size if
543 the entry is compressed.
545 It is also possible to list just some files in an image, e.g.
547 $ binman ls -i image.bin section/cbfs
548 Name Image-pos Size Entry-type Offset Uncomp-size
549 --------------------------------------------------------------------
551 u-boot 138 4 u-boot 38
552 u-boot-dtb 180 108 u-boot-dtb 80 3b5
556 $ binman ls -i image.bin "*cb*" "*head*"
557 Name Image-pos Size Entry-type Offset Uncomp-size
558 ----------------------------------------------------------------------
560 u-boot 138 4 u-boot 38
561 u-boot-dtb 180 108 u-boot-dtb 80 3b5
562 image-header bf8 8 image-header bf8
565 Extracting files from images
566 ----------------------------
568 You can extract files from an existing firmware image created by binman,
569 provided that there is an 'fdtmap' entry in the image. For example:
571 $ binman extract -i image.bin section/cbfs/u-boot
573 which will write the uncompressed contents of that entry to the file 'u-boot' in
574 the current directory. You can also extract to a particular file, in this case
577 $ binman extract -i image.bin section/cbfs/u-boot -f u-boot.bin
579 It is possible to extract all files into a destination directory, which will
580 put files in subdirectories matching the entry hierarchy:
582 $ binman extract -i image.bin -O outdir
586 $ binman extract -i image.bin "*u-boot*" -O outdir
589 Replacing files in an image
590 ---------------------------
592 You can replace files in an existing firmware image created by binman, provided
593 that there is an 'fdtmap' entry in the image. For example:
595 $ binman replace -i image.bin section/cbfs/u-boot
597 which will write the contents of the file 'u-boot' from the current directory
598 to the that entry, compressing if necessary. If the entry size changes, you must
599 add the 'allow-repack' property to the original image before generating it (see
600 above), otherwise you will get an error.
602 You can also use a particular file, in this case u-boot.bin:
604 $ binman replace -i image.bin section/cbfs/u-boot -f u-boot.bin
606 It is possible to replace all files from a source directory which uses the same
607 hierarchy as the entries:
609 $ binman replace -i image.bin -I indir
611 Files that are missing will generate a warning.
613 You can also replace just a selection of entries:
615 $ binman replace -i image.bin "*u-boot*" -I indir
621 Binman normally operates silently unless there is an error, in which case it
622 just displays the error. The -D/--debug option can be used to create a full
623 backtrace when errors occur.
625 Internally binman logs some output while it is running. This can be displayed
626 by increasing the -v/--verbosity from the default of 1:
630 2: notices (important messages)
631 3: info about major operations
632 4: detailed information about each operation
633 5: debug (all output)
639 It is possible to ask binman to hash the contents of an entry and write that
640 value back to the device-tree node. For example:
650 Here, a new 'value' property will be written to the 'hash' node containing
651 the hash of the 'u-boot' entry. Only SHA256 is supported at present. Whole
652 sections can be hased if desired, by adding the 'hash' node to the section.
654 The has value can be chcked at runtime by hashing the data actually read and
655 comparing this has to the value in the device tree.
658 Order of image creation
659 -----------------------
661 Image creation proceeds in the following order, for each entry in the image.
663 1. AddMissingProperties() - binman can add calculated values to the device
664 tree as part of its processing, for example the offset and size of each
665 entry. This method adds any properties associated with this, expanding the
666 device tree as needed. These properties can have placeholder values which are
667 set later by SetCalculatedProperties(). By that stage the size of sections
668 cannot be changed (since it would cause the images to need to be repacked),
669 but the correct values can be inserted.
671 2. ProcessFdt() - process the device tree information as required by the
672 particular entry. This may involve adding or deleting properties. If the
673 processing is complete, this method should return True. If the processing
674 cannot complete because it needs the ProcessFdt() method of another entry to
675 run first, this method should return False, in which case it will be called
678 3. GetEntryContents() - the contents of each entry are obtained, normally by
679 reading from a file. This calls the Entry.ObtainContents() to read the
680 contents. The default version of Entry.ObtainContents() calls
681 Entry.GetDefaultFilename() and then reads that file. So a common mechanism
682 to select a file to read is to override that function in the subclass. The
683 functions must return True when they have read the contents. Binman will
684 retry calling the functions a few times if False is returned, allowing
685 dependencies between the contents of different entries.
687 4. GetEntryOffsets() - calls Entry.GetOffsets() for each entry. This can
688 return a dict containing entries that need updating. The key should be the
689 entry name and the value is a tuple (offset, size). This allows an entry to
690 provide the offset and size for other entries. The default implementation
691 of GetEntryOffsets() returns {}.
693 5. PackEntries() - calls Entry.Pack() which figures out the offset and
694 size of an entry. The 'current' image offset is passed in, and the function
695 returns the offset immediately after the entry being packed. The default
696 implementation of Pack() is usually sufficient.
698 6. CheckSize() - checks that the contents of all the entries fits within
699 the image size. If the image does not have a defined size, the size is set
700 large enough to hold all the entries.
702 7. CheckEntries() - checks that the entries do not overlap, nor extend
705 8. SetImagePos() - sets the image position of every entry. This is the absolute
706 position 'image-pos', as opposed to 'offset' which is relative to the containing
707 section. This must be done after all offsets are known, which is why it is quite
708 late in the ordering.
710 9. SetCalculatedProperties() - update any calculated properties in the device
711 tree. This sets the correct 'offset' and 'size' vaues, for example.
713 10. ProcessEntryContents() - this calls Entry.ProcessContents() on each entry.
714 The default implementatoin does nothing. This can be overriden to adjust the
715 contents of an entry in some way. For example, it would be possible to create
716 an entry containing a hash of the contents of some other entries. At this
717 stage the offset and size of entries should not be adjusted unless absolutely
718 necessary, since it requires a repack (going back to PackEntries()).
720 11. ResetForPack() - if the ProcessEntryContents() step failed, in that an entry
721 has changed its size, then there is no alternative but to go back to step 5 and
722 try again, repacking the entries with the updated size. ResetForPack() removes
723 the fixed offset/size values added by binman, so that the packing can start from
726 12. WriteSymbols() - write the value of symbols into the U-Boot SPL binary.
727 See 'Access to binman entry offsets at run time' below for a description of
728 what happens in this stage.
730 13. BuildImage() - builds the image and writes it to a file
732 14. WriteMap() - writes a text file containing a map of the image. This is the
736 Automatic .dtsi inclusion
737 -------------------------
739 It is sometimes inconvenient to add a 'binman' node to the .dts file for each
740 board. This can be done by using #include to bring in a common file. Another
741 approach supported by the U-Boot build system is to automatically include
742 a common header. You can then put the binman node (and anything else that is
743 specific to U-Boot, such as u-boot,dm-pre-reloc properies) in that header
746 Binman will search for the following files in arch/<arch>/dts:
748 <dts>-u-boot.dtsi where <dts> is the base name of the .dts file
749 <CONFIG_SYS_SOC>-u-boot.dtsi
750 <CONFIG_SYS_CPU>-u-boot.dtsi
751 <CONFIG_SYS_VENDOR>-u-boot.dtsi
754 U-Boot will only use the first one that it finds. If you need to include a
755 more general file you can do that from the more specific file using #include.
756 If you are having trouble figuring out what is going on, you can uncomment
757 the 'warning' line in scripts/Makefile.lib to see what it has found:
759 # Uncomment for debugging
760 # This shows all the files that were considered and the one that we chose.
761 # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
764 Access to binman entry offsets at run time (symbols)
765 ----------------------------------------------------
767 Binman assembles images and determines where each entry is placed in the image.
768 This information may be useful to U-Boot at run time. For example, in SPL it
769 is useful to be able to find the location of U-Boot so that it can be executed
770 when SPL is finished.
772 Binman allows you to declare symbols in the SPL image which are filled in
773 with their correct values during the build. For example:
775 binman_sym_declare(ulong, u_boot_any, image_pos);
777 declares a ulong value which will be assigned to the image-pos of any U-Boot
778 image (u-boot.bin, u-boot.img, u-boot-nodtb.bin) that is present in the image.
779 You can access this value with something like:
781 ulong u_boot_offset = binman_sym(ulong, u_boot_any, image_pos);
783 Thus u_boot_offset will be set to the image-pos of U-Boot in memory, assuming
784 that the whole image has been loaded, or is available in flash. You can then
785 jump to that address to start U-Boot.
787 At present this feature is only supported in SPL and TPL. In principle it is
788 possible to fill in such symbols in U-Boot proper, as well, but a future C
789 library is planned for this instead, to read from the device tree.
791 As well as image-pos, it is possible to read the size of an entry and its
792 offset (which is the start position of the entry within its parent).
794 A small technical note: Binman automatically adds the base address of the image
795 (i.e. __image_copy_start) to the value of the image-pos symbol, so that when the
796 image is loaded to its linked address, the value will be correct and actually
797 point into the image.
799 For example, say SPL is at the start of the image and linked to start at address
800 80108000. If U-Boot's image-pos is 0x8000 then binman will write an image-pos
801 for U-Boot of 80110000 into the SPL binary, since it assumes the image is loaded
802 to 80108000, with SPL at 80108000 and U-Boot at 80110000.
804 For x86 devices (with the end-at-4gb property) this base address is not added
805 since it is assumed that images are XIP and the offsets already include the
809 Access to binman entry offsets at run time (fdt)
810 ------------------------------------------------
812 Binman can update the U-Boot FDT to include the final position and size of
813 each entry in the images it processes. The option to enable this is -u and it
814 causes binman to make sure that the 'offset', 'image-pos' and 'size' properties
815 are set correctly for every entry. Since it is not necessary to specify these in
816 the image definition, binman calculates the final values and writes these to
817 the device tree. These can be used by U-Boot at run-time to find the location
820 Alternatively, an FDT map entry can be used to add a special FDT containing
821 just the information about the image. This is preceded by a magic string so can
822 be located anywhere in the image. An image header (typically at the start or end
823 of the image) can be used to point to the FDT map. See fdtmap and image-header
824 entries for more information.
830 Binman support compression for 'blob' entries (those of type 'blob' and
831 derivatives). To enable this for an entry, add a 'compress' property:
834 filename = "datafile";
838 The entry will then contain the compressed data, using the 'lz4' compression
839 algorithm. Currently this is the only one that is supported. The uncompressed
840 size is written to the node in an 'uncomp-size' property, if -u is used.
847 The -m option causes binman to output a .map file for each image that it
848 generates. This shows the offset and size of each entry. For example:
851 00000000 00000028 main-section
852 00000000 00000010 section@0
853 00000000 00000004 u-boot
854 00000010 00000010 section@1
855 00000000 00000004 u-boot
857 This shows a hierarchical image with two sections, each with a single entry. The
858 offsets of the sections are absolute hex byte offsets within the image. The
859 offsets of the entries are relative to their respective sections. The size of
860 each entry is also shown, in bytes (hex). The indentation shows the entries
861 nested inside their sections.
864 Passing command-line arguments to entries
865 -----------------------------------------
867 Sometimes it is useful to pass binman the value of an entry property from the
868 command line. For example some entries need access to files and it is not
869 always convenient to put these filenames in the image definition (device tree).
871 The-a option supports this:
877 <prop> is the property to set
878 <value> is the value to set it to
880 Not all properties can be provided this way. Only some entries support it,
881 typically for filenames.
887 Binman can make use of external command-line tools to handle processing of
888 entry contents or to generate entry contents. These tools are executed using
889 the 'tools' module's Run() method. The tools generally must exist on the PATH,
890 but the --toolpath option can be used to specify additional search paths to
891 use. This option can be specified multiple times to add more than one path.
893 For some compile tools binman will use the versions specified by commonly-used
894 environment variables like CC and HOSTCC for the C compiler, based on whether
895 the tool's output will be used for the target or for the host machine. If those
896 aren't given, it will also try to derive target-specific versions from the
897 CROSS_COMPILE environment variable during a cross-compilation.
903 Binman is a critical tool and is designed to be very testable. Entry
904 implementations target 100% test coverage. Run 'binman test -T' to check this.
906 To enable Python test coverage on Debian-type distributions (e.g. Ubuntu):
908 $ sudo apt-get install python-coverage python3-coverage python-pytest
914 Binman tries to run tests concurrently. This means that the tests make use of
915 all available CPUs to run.
919 $ sudo apt-get install python-subunit python3-subunit
921 Use '-P 1' to disable this. It is automatically disabled when code coverage is
922 being used (-T) since they are incompatible.
928 Sometimes when debugging tests it is useful to keep the input and output
929 directories so they can be examined later. Use -X or --test-preserve-dirs for
933 Running tests on non-x86 architectures
934 --------------------------------------
936 Binman's tests have been written under the assumption that they'll be run on a
937 x86-like host and there hasn't been an attempt to make them portable yet.
938 However, it's possible to run the tests by cross-compiling to x86.
940 To install an x86 cross-compiler on Debian-type distributions (e.g. Ubuntu):
942 $ sudo apt-get install gcc-x86-64-linux-gnu
944 Then, you can run the tests under cross-compilation:
946 $ CROSS_COMPILE=x86_64-linux-gnu- binman test -T
948 You can also use gcc-i686-linux-gnu similar to the above.
951 Advanced Features / Technical docs
952 ----------------------------------
954 The behaviour of entries is defined by the Entry class. All other entries are
955 a subclass of this. An important subclass is Entry_blob which takes binary
956 data from a file and places it in the entry. In fact most entry types are
957 subclasses of Entry_blob.
959 Each entry type is a separate file in the tools/binman/etype directory. Each
960 file contains a class called Entry_<type> where <type> is the entry type.
961 New entry types can be supported by adding new files in that directory.
962 These will automatically be detected by binman when needed.
964 Entry properties are documented in entry.py. The entry subclasses are free
965 to change the values of properties to support special behaviour. For example,
966 when Entry_blob loads a file, it sets content_size to the size of the file.
967 Entry classes can adjust other entries. For example, an entry that knows
968 where other entries should be positioned can set up those entries' offsets
969 so they don't need to be set in the binman decription. It can also adjust
972 Most of the time such essoteric behaviour is not needed, but it can be
973 essential for complex images.
975 If you need to specify a particular device-tree compiler to use, you can define
976 the DTC environment variable. This can be useful when the system dtc is too
979 To enable a full backtrace and other debugging features in binman, pass
980 BINMAN_DEBUG=1 to your build:
982 make qemu-x86_defconfig
985 To enable verbose logging from binman, base BINMAN_VERBOSE to your build, which
986 adds a -v<level> option to the call to binman:
988 make qemu-x86_defconfig
989 make BINMAN_VERBOSE=5
995 Binman takes a lot of inspiration from a Chrome OS tool called
996 'cros_bundle_firmware', which I wrote some years ago. That tool was based on
997 a reasonably simple and sound design but has expanded greatly over the
998 years. In particular its handling of x86 images is convoluted.
1000 Quite a few lessons have been learned which are hopefully applied here.
1006 On the face of it, a tool to create firmware images should be fairly simple:
1007 just find all the input binaries and place them at the right place in the
1008 image. The difficulty comes from the wide variety of input types (simple
1009 flat binaries containing code, packaged data with various headers), packing
1010 requirments (alignment, spacing, device boundaries) and other required
1011 features such as hierarchical images.
1013 The design challenge is to make it easy to create simple images, while
1014 allowing the more complex cases to be supported. For example, for most
1015 images we don't much care exactly where each binary ends up, so we should
1016 not have to specify that unnecessarily.
1018 New entry types should aim to provide simple usage where possible. If new
1019 core features are needed, they can be added in the Entry base class.
1026 - Use of-platdata to make the information available to code that is unable
1027 to use device tree (such as a very small SPL image)
1028 - Allow easy building of images by specifying just the board name
1029 - Support building an image for a board (-b) more completely, with a
1030 configurable build directory
1031 - Support adding FITs to an image
1032 - Support for ARM Trusted Firmware (ATF)
1033 - Detect invalid properties in nodes
1034 - Sort the fdtmap by offset
1037 Simon Glass <sjg@chromium.org>