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 containing
282 section or image. For example 'align = <16>' means that the entry will
283 start on a 16-byte boundary. This may mean that padding is added before
284 the entry. The padding is part of the containing section but is not
285 included in the entry, meaning that an empty space may be created before
286 the entry starts. Alignment should be a power of 2. If 'align' is not
287 provided, no alignment is performed.
290 This sets the size of the entry. The contents will be padded out to
291 this size. If this is not provided, it will be set to the size of the
295 Padding before the contents of the entry. Normally this is 0, meaning
296 that the contents start at the beginning of the entry. This can be used
297 to offset the entry contents a little. While this does not affect the
298 contents of the entry within binman itself (the padding is performed
299 only when its parent section is assembled), the end result will be that
300 the entry starts with the padding bytes, so may grow. Defaults to 0.
303 Padding after the contents of the entry. Normally this is 0, meaning
304 that the entry ends at the last byte of content (unless adjusted by
305 other properties). This allows room to be created in the image for
306 this entry to expand later. While this does not affect the contents of
307 the entry within binman itself (the padding is performed only when its
308 parent section is assembled), the end result will be that the entry ends
309 with the padding bytes, so may grow. Defaults to 0.
312 This sets the alignment of the entry size. For example, to ensure
313 that the size of an entry is a multiple of 64 bytes, set this to 64.
314 While this does not affect the contents of the entry within binman
315 itself (the padding is performed only when its parent section is
316 assembled), the end result is that the entry ends with the padding
317 bytes, so may grow. If 'align-size' is not provided, no alignment is
321 This sets the alignment of the end of an entry with respect to the
322 containing section. Some entries require that they end on an alignment
323 boundary, regardless of where they start. This does not move the start
324 of the entry, so the contents of the entry will still start at the
325 beginning. But there may be padding at the end. While this does not
326 affect the contents of the entry within binman itself (the padding is
327 performed only when its parent section is assembled), the end result
328 is that the entry ends with the padding bytes, so may grow.
329 If 'align-end' is not provided, no alignment is performed.
332 For 'blob' types this provides the filename containing the binary to
333 put into the entry. If binman knows about the entry type (like
334 u-boot-bin), then there is no need to specify this.
337 Sets the type of an entry. This defaults to the entry name, but it is
338 possible to use any name, and then add (for example) 'type = "u-boot"'
342 Indicates that the offset of this entry should not be set by placing
343 it immediately after the entry before. Instead, is set by another
344 entry which knows where this entry should go. When this boolean
345 property is present, binman will give an error if another entry does
346 not set the offset (with the GetOffsets() method).
349 This cannot be set on entry (or at least it is ignored if it is), but
350 with the -u option, binman will set it to the absolute image position
351 for each entry. This makes it easy to find out exactly where the entry
352 ended up in the image, regardless of parent sections, etc.
355 Expand the size of this entry to fit available space. This space is only
356 limited by the size of the image/section and the position of the next
360 Sets the compression algortihm to use (for blobs only). See the entry
361 documentation for details.
364 Sets the tag of the message to show if this entry is missing. This is
365 used for external blobs. When they are missing it is helpful to show
366 information about what needs to be fixed. See missing-blob-help for the
367 message for each tag.
369 The attributes supported for images and sections are described below. Several
370 are similar to those for entries.
373 Sets the image size in bytes, for example 'size = <0x100000>' for a
377 This is similar to 'offset' in entries, setting the offset of a section
378 within the image or section containing it. The first byte of the section
379 is normally at offset 0. If 'offset' is not provided, binman sets it to
380 the end of the previous region, or the start of the image's entry area
381 (normally 0) if there is no previous region.
384 This sets the alignment of the image size. For example, to ensure
385 that the image ends on a 512-byte boundary, use 'align-size = <512>'.
386 If 'align-size' is not provided, no alignment is performed.
389 This sets the padding before the image entries. The first entry will
390 be positioned after the padding. This defaults to 0.
393 This sets the padding after the image entries. The padding will be
394 placed after the last entry. This defaults to 0.
397 This specifies the pad byte to use when padding in the image. It
398 defaults to 0. To use 0xff, you would add 'pad-byte = <0xff>'.
401 This specifies the image filename. It defaults to 'image.bin'.
404 This causes binman to reorder the entries as needed to make sure they
405 are in increasing positional order. This can be used when your entry
406 order may not match the positional order. A common situation is where
407 the 'offset' properties are set by CONFIG options, so their ordering is
410 This is a boolean property so needs no value. To enable it, add a
411 line 'sort-by-offset;' to your description.
414 Normally only a single image is generated. To create more than one
415 image, put this property in the binman node. For example, this will
416 create image1.bin containing u-boot.bin, and image2.bin containing
417 both spl/u-boot-spl.bin and u-boot.bin:
435 For x86 machines the ROM offsets start just before 4GB and extend
436 up so that the image finished at the 4GB boundary. This boolean
437 option can be enabled to support this. The image size must be
438 provided so that binman knows when the image should start. For an
439 8MB ROM, the offset of the first entry would be 0xfff80000 with
440 this option, instead of 0 without this option.
443 This property specifies the entry offset of the first entry.
445 For PowerPC mpc85xx based CPU, CONFIG_SYS_TEXT_BASE is the entry
446 offset of the first entry. It can be 0xeff40000 or 0xfff40000 for
447 nor flash boot, 0x201000 for sd boot etc.
449 'end-at-4gb' property is not applicable where CONFIG_SYS_TEXT_BASE +
452 Examples of the above options can be found in the tests. See the
453 tools/binman/test directory.
455 It is possible to have the same binary appear multiple times in the image,
456 either by using a unit number suffix (u-boot@0, u-boot@1) or by using a
457 different name for each and specifying the type with the 'type' attribute.
460 Sections and hierachical images
461 -------------------------------
463 Sometimes it is convenient to split an image into several pieces, each of which
464 contains its own set of binaries. An example is a flash device where part of
465 the image is read-only and part is read-write. We can set up sections for each
466 of these, and place binaries in them independently. The image is still produced
467 as a single output file.
469 This feature provides a way of creating hierarchical images. For example here
470 is an example image with two copies of U-Boot. One is read-only (ro), intended
471 to be written only in the factory. Another is read-write (rw), so that it can be
472 upgraded in the field. The sizes are fixed so that the ro/rw boundary is known
473 and can be programmed:
491 This image could be placed into a SPI flash chip, with the protection boundary
494 A few special properties are provided for sections:
497 Indicates that this section is read-only. This has no impact on binman's
498 operation, but his property can be read at run time.
501 This string is prepended to all the names of the binaries in the
502 section. In the example above, the 'u-boot' binaries which actually be
503 renamed to 'ro-u-boot' and 'rw-u-boot'. This can be useful to
504 distinguish binaries with otherwise identical names.
510 Image nodes act like sections but also have a few extra properties:
513 Output filename for the image. This defaults to image.bin (or in the
514 case of multiple images <nodename>.bin where <nodename> is the name of
518 Create an image that can be repacked. With this option it is possible
519 to change anything in the image after it is created, including updating
520 the position and size of image components. By default this is not
521 permitted since it is not possibly to know whether this might violate a
522 constraint in the image description. For example, if a section has to
523 increase in size to hold a larger binary, that might cause the section
524 to fall out of its allow region (e.g. read-only portion of flash).
526 Adding this property causes the original offset and size values in the
527 image description to be stored in the FDT and fdtmap.
533 For details on the various entry types supported by binman and how to use them,
534 see README.entries. This is generated from the source code using:
536 binman entry-docs >tools/binman/README.entries
542 It is possible to list the entries in an existing firmware image created by
543 binman, provided that there is an 'fdtmap' entry in the image. For example:
545 $ binman ls -i image.bin
546 Name Image-pos Size Entry-type Offset Uncomp-size
547 ----------------------------------------------------------------------
548 main-section c00 section 0
550 section 5fc section 4
552 u-boot 138 4 u-boot 38
553 u-boot-dtb 180 108 u-boot-dtb 80 3b5
554 u-boot-dtb 500 1ff u-boot-dtb 400 3b5
555 fdtmap 6fc 381 fdtmap 6fc
556 image-header bf8 8 image-header bf8
558 This shows the hierarchy of the image, the position, size and type of each
559 entry, the offset of each entry within its parent and the uncompressed size if
560 the entry is compressed.
562 It is also possible to list just some files in an image, e.g.
564 $ binman ls -i image.bin section/cbfs
565 Name Image-pos Size Entry-type Offset Uncomp-size
566 --------------------------------------------------------------------
568 u-boot 138 4 u-boot 38
569 u-boot-dtb 180 108 u-boot-dtb 80 3b5
573 $ binman ls -i image.bin "*cb*" "*head*"
574 Name Image-pos Size Entry-type Offset Uncomp-size
575 ----------------------------------------------------------------------
577 u-boot 138 4 u-boot 38
578 u-boot-dtb 180 108 u-boot-dtb 80 3b5
579 image-header bf8 8 image-header bf8
582 Extracting files from images
583 ----------------------------
585 You can extract files from an existing firmware image created by binman,
586 provided that there is an 'fdtmap' entry in the image. For example:
588 $ binman extract -i image.bin section/cbfs/u-boot
590 which will write the uncompressed contents of that entry to the file 'u-boot' in
591 the current directory. You can also extract to a particular file, in this case
594 $ binman extract -i image.bin section/cbfs/u-boot -f u-boot.bin
596 It is possible to extract all files into a destination directory, which will
597 put files in subdirectories matching the entry hierarchy:
599 $ binman extract -i image.bin -O outdir
603 $ binman extract -i image.bin "*u-boot*" -O outdir
606 Replacing files in an image
607 ---------------------------
609 You can replace files in an existing firmware image created by binman, provided
610 that there is an 'fdtmap' entry in the image. For example:
612 $ binman replace -i image.bin section/cbfs/u-boot
614 which will write the contents of the file 'u-boot' from the current directory
615 to the that entry, compressing if necessary. If the entry size changes, you must
616 add the 'allow-repack' property to the original image before generating it (see
617 above), otherwise you will get an error.
619 You can also use a particular file, in this case u-boot.bin:
621 $ binman replace -i image.bin section/cbfs/u-boot -f u-boot.bin
623 It is possible to replace all files from a source directory which uses the same
624 hierarchy as the entries:
626 $ binman replace -i image.bin -I indir
628 Files that are missing will generate a warning.
630 You can also replace just a selection of entries:
632 $ binman replace -i image.bin "*u-boot*" -I indir
638 Binman normally operates silently unless there is an error, in which case it
639 just displays the error. The -D/--debug option can be used to create a full
640 backtrace when errors occur.
642 Internally binman logs some output while it is running. This can be displayed
643 by increasing the -v/--verbosity from the default of 1:
647 2: notices (important messages)
648 3: info about major operations
649 4: detailed information about each operation
650 5: debug (all output)
656 It is possible to ask binman to hash the contents of an entry and write that
657 value back to the device-tree node. For example:
667 Here, a new 'value' property will be written to the 'hash' node containing
668 the hash of the 'u-boot' entry. Only SHA256 is supported at present. Whole
669 sections can be hased if desired, by adding the 'hash' node to the section.
671 The has value can be chcked at runtime by hashing the data actually read and
672 comparing this has to the value in the device tree.
675 Order of image creation
676 -----------------------
678 Image creation proceeds in the following order, for each entry in the image.
680 1. AddMissingProperties() - binman can add calculated values to the device
681 tree as part of its processing, for example the offset and size of each
682 entry. This method adds any properties associated with this, expanding the
683 device tree as needed. These properties can have placeholder values which are
684 set later by SetCalculatedProperties(). By that stage the size of sections
685 cannot be changed (since it would cause the images to need to be repacked),
686 but the correct values can be inserted.
688 2. ProcessFdt() - process the device tree information as required by the
689 particular entry. This may involve adding or deleting properties. If the
690 processing is complete, this method should return True. If the processing
691 cannot complete because it needs the ProcessFdt() method of another entry to
692 run first, this method should return False, in which case it will be called
695 3. GetEntryContents() - the contents of each entry are obtained, normally by
696 reading from a file. This calls the Entry.ObtainContents() to read the
697 contents. The default version of Entry.ObtainContents() calls
698 Entry.GetDefaultFilename() and then reads that file. So a common mechanism
699 to select a file to read is to override that function in the subclass. The
700 functions must return True when they have read the contents. Binman will
701 retry calling the functions a few times if False is returned, allowing
702 dependencies between the contents of different entries.
704 4. GetEntryOffsets() - calls Entry.GetOffsets() for each entry. This can
705 return a dict containing entries that need updating. The key should be the
706 entry name and the value is a tuple (offset, size). This allows an entry to
707 provide the offset and size for other entries. The default implementation
708 of GetEntryOffsets() returns {}.
710 5. PackEntries() - calls Entry.Pack() which figures out the offset and
711 size of an entry. The 'current' image offset is passed in, and the function
712 returns the offset immediately after the entry being packed. The default
713 implementation of Pack() is usually sufficient.
715 Note: for sections, this also checks that the entries do not overlap, nor extend
716 outside the section. If the section does not have a defined size, the size is
717 set large enough to hold all the entries.
719 6. SetImagePos() - sets the image position of every entry. This is the absolute
720 position 'image-pos', as opposed to 'offset' which is relative to the containing
721 section. This must be done after all offsets are known, which is why it is quite
722 late in the ordering.
724 7. SetCalculatedProperties() - update any calculated properties in the device
725 tree. This sets the correct 'offset' and 'size' vaues, for example.
727 8. ProcessEntryContents() - this calls Entry.ProcessContents() on each entry.
728 The default implementatoin does nothing. This can be overriden to adjust the
729 contents of an entry in some way. For example, it would be possible to create
730 an entry containing a hash of the contents of some other entries. At this
731 stage the offset and size of entries should not be adjusted unless absolutely
732 necessary, since it requires a repack (going back to PackEntries()).
734 9. ResetForPack() - if the ProcessEntryContents() step failed, in that an entry
735 has changed its size, then there is no alternative but to go back to step 5 and
736 try again, repacking the entries with the updated size. ResetForPack() removes
737 the fixed offset/size values added by binman, so that the packing can start from
740 10. WriteSymbols() - write the value of symbols into the U-Boot SPL binary.
741 See 'Access to binman entry offsets at run time' below for a description of
742 what happens in this stage.
744 11. BuildImage() - builds the image and writes it to a file
746 12. WriteMap() - writes a text file containing a map of the image. This is the
750 Automatic .dtsi inclusion
751 -------------------------
753 It is sometimes inconvenient to add a 'binman' node to the .dts file for each
754 board. This can be done by using #include to bring in a common file. Another
755 approach supported by the U-Boot build system is to automatically include
756 a common header. You can then put the binman node (and anything else that is
757 specific to U-Boot, such as u-boot,dm-pre-reloc properies) in that header
760 Binman will search for the following files in arch/<arch>/dts:
762 <dts>-u-boot.dtsi where <dts> is the base name of the .dts file
763 <CONFIG_SYS_SOC>-u-boot.dtsi
764 <CONFIG_SYS_CPU>-u-boot.dtsi
765 <CONFIG_SYS_VENDOR>-u-boot.dtsi
768 U-Boot will only use the first one that it finds. If you need to include a
769 more general file you can do that from the more specific file using #include.
770 If you are having trouble figuring out what is going on, you can uncomment
771 the 'warning' line in scripts/Makefile.lib to see what it has found:
773 # Uncomment for debugging
774 # This shows all the files that were considered and the one that we chose.
775 # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
778 Access to binman entry offsets at run time (symbols)
779 ----------------------------------------------------
781 Binman assembles images and determines where each entry is placed in the image.
782 This information may be useful to U-Boot at run time. For example, in SPL it
783 is useful to be able to find the location of U-Boot so that it can be executed
784 when SPL is finished.
786 Binman allows you to declare symbols in the SPL image which are filled in
787 with their correct values during the build. For example:
789 binman_sym_declare(ulong, u_boot_any, image_pos);
791 declares a ulong value which will be assigned to the image-pos of any U-Boot
792 image (u-boot.bin, u-boot.img, u-boot-nodtb.bin) that is present in the image.
793 You can access this value with something like:
795 ulong u_boot_offset = binman_sym(ulong, u_boot_any, image_pos);
797 Thus u_boot_offset will be set to the image-pos of U-Boot in memory, assuming
798 that the whole image has been loaded, or is available in flash. You can then
799 jump to that address to start U-Boot.
801 At present this feature is only supported in SPL and TPL. In principle it is
802 possible to fill in such symbols in U-Boot proper, as well, but a future C
803 library is planned for this instead, to read from the device tree.
805 As well as image-pos, it is possible to read the size of an entry and its
806 offset (which is the start position of the entry within its parent).
808 A small technical note: Binman automatically adds the base address of the image
809 (i.e. __image_copy_start) to the value of the image-pos symbol, so that when the
810 image is loaded to its linked address, the value will be correct and actually
811 point into the image.
813 For example, say SPL is at the start of the image and linked to start at address
814 80108000. If U-Boot's image-pos is 0x8000 then binman will write an image-pos
815 for U-Boot of 80110000 into the SPL binary, since it assumes the image is loaded
816 to 80108000, with SPL at 80108000 and U-Boot at 80110000.
818 For x86 devices (with the end-at-4gb property) this base address is not added
819 since it is assumed that images are XIP and the offsets already include the
823 Access to binman entry offsets at run time (fdt)
824 ------------------------------------------------
826 Binman can update the U-Boot FDT to include the final position and size of
827 each entry in the images it processes. The option to enable this is -u and it
828 causes binman to make sure that the 'offset', 'image-pos' and 'size' properties
829 are set correctly for every entry. Since it is not necessary to specify these in
830 the image definition, binman calculates the final values and writes these to
831 the device tree. These can be used by U-Boot at run-time to find the location
834 Alternatively, an FDT map entry can be used to add a special FDT containing
835 just the information about the image. This is preceded by a magic string so can
836 be located anywhere in the image. An image header (typically at the start or end
837 of the image) can be used to point to the FDT map. See fdtmap and image-header
838 entries for more information.
844 Binman support compression for 'blob' entries (those of type 'blob' and
845 derivatives). To enable this for an entry, add a 'compress' property:
848 filename = "datafile";
852 The entry will then contain the compressed data, using the 'lz4' compression
853 algorithm. Currently this is the only one that is supported. The uncompressed
854 size is written to the node in an 'uncomp-size' property, if -u is used.
861 The -m option causes binman to output a .map file for each image that it
862 generates. This shows the offset and size of each entry. For example:
865 00000000 00000028 main-section
866 00000000 00000010 section@0
867 00000000 00000004 u-boot
868 00000010 00000010 section@1
869 00000000 00000004 u-boot
871 This shows a hierarchical image with two sections, each with a single entry. The
872 offsets of the sections are absolute hex byte offsets within the image. The
873 offsets of the entries are relative to their respective sections. The size of
874 each entry is also shown, in bytes (hex). The indentation shows the entries
875 nested inside their sections.
878 Passing command-line arguments to entries
879 -----------------------------------------
881 Sometimes it is useful to pass binman the value of an entry property from the
882 command line. For example some entries need access to files and it is not
883 always convenient to put these filenames in the image definition (device tree).
885 The-a option supports this:
891 <prop> is the property to set
892 <value> is the value to set it to
894 Not all properties can be provided this way. Only some entries support it,
895 typically for filenames.
901 Binman can make use of external command-line tools to handle processing of
902 entry contents or to generate entry contents. These tools are executed using
903 the 'tools' module's Run() method. The tools generally must exist on the PATH,
904 but the --toolpath option can be used to specify additional search paths to
905 use. This option can be specified multiple times to add more than one path.
907 For some compile tools binman will use the versions specified by commonly-used
908 environment variables like CC and HOSTCC for the C compiler, based on whether
909 the tool's output will be used for the target or for the host machine. If those
910 aren't given, it will also try to derive target-specific versions from the
911 CROSS_COMPILE environment variable during a cross-compilation.
917 Binman is a critical tool and is designed to be very testable. Entry
918 implementations target 100% test coverage. Run 'binman test -T' to check this.
920 To enable Python test coverage on Debian-type distributions (e.g. Ubuntu):
922 $ sudo apt-get install python-coverage python3-coverage python-pytest
928 Binman tries to run tests concurrently. This means that the tests make use of
929 all available CPUs to run.
933 $ sudo apt-get install python-subunit python3-subunit
935 Use '-P 1' to disable this. It is automatically disabled when code coverage is
936 being used (-T) since they are incompatible.
942 Sometimes when debugging tests it is useful to keep the input and output
943 directories so they can be examined later. Use -X or --test-preserve-dirs for
947 Running tests on non-x86 architectures
948 --------------------------------------
950 Binman's tests have been written under the assumption that they'll be run on a
951 x86-like host and there hasn't been an attempt to make them portable yet.
952 However, it's possible to run the tests by cross-compiling to x86.
954 To install an x86 cross-compiler on Debian-type distributions (e.g. Ubuntu):
956 $ sudo apt-get install gcc-x86-64-linux-gnu
958 Then, you can run the tests under cross-compilation:
960 $ CROSS_COMPILE=x86_64-linux-gnu- binman test -T
962 You can also use gcc-i686-linux-gnu similar to the above.
965 Advanced Features / Technical docs
966 ----------------------------------
968 The behaviour of entries is defined by the Entry class. All other entries are
969 a subclass of this. An important subclass is Entry_blob which takes binary
970 data from a file and places it in the entry. In fact most entry types are
971 subclasses of Entry_blob.
973 Each entry type is a separate file in the tools/binman/etype directory. Each
974 file contains a class called Entry_<type> where <type> is the entry type.
975 New entry types can be supported by adding new files in that directory.
976 These will automatically be detected by binman when needed.
978 Entry properties are documented in entry.py. The entry subclasses are free
979 to change the values of properties to support special behaviour. For example,
980 when Entry_blob loads a file, it sets content_size to the size of the file.
981 Entry classes can adjust other entries. For example, an entry that knows
982 where other entries should be positioned can set up those entries' offsets
983 so they don't need to be set in the binman decription. It can also adjust
986 Most of the time such essoteric behaviour is not needed, but it can be
987 essential for complex images.
989 If you need to specify a particular device-tree compiler to use, you can define
990 the DTC environment variable. This can be useful when the system dtc is too
993 To enable a full backtrace and other debugging features in binman, pass
994 BINMAN_DEBUG=1 to your build:
996 make qemu-x86_defconfig
999 To enable verbose logging from binman, base BINMAN_VERBOSE to your build, which
1000 adds a -v<level> option to the call to binman:
1002 make qemu-x86_defconfig
1003 make BINMAN_VERBOSE=5
1009 Binman takes a lot of inspiration from a Chrome OS tool called
1010 'cros_bundle_firmware', which I wrote some years ago. That tool was based on
1011 a reasonably simple and sound design but has expanded greatly over the
1012 years. In particular its handling of x86 images is convoluted.
1014 Quite a few lessons have been learned which are hopefully applied here.
1020 On the face of it, a tool to create firmware images should be fairly simple:
1021 just find all the input binaries and place them at the right place in the
1022 image. The difficulty comes from the wide variety of input types (simple
1023 flat binaries containing code, packaged data with various headers), packing
1024 requirments (alignment, spacing, device boundaries) and other required
1025 features such as hierarchical images.
1027 The design challenge is to make it easy to create simple images, while
1028 allowing the more complex cases to be supported. For example, for most
1029 images we don't much care exactly where each binary ends up, so we should
1030 not have to specify that unnecessarily.
1032 New entry types should aim to provide simple usage where possible. If new
1033 core features are needed, they can be added in the Entry base class.
1040 - Use of-platdata to make the information available to code that is unable
1041 to use device tree (such as a very small SPL image)
1042 - Allow easy building of images by specifying just the board name
1043 - Support building an image for a board (-b) more completely, with a
1044 configurable build directory
1045 - Support adding FITs to an image
1046 - Support for ARM Trusted Firmware (ATF)
1047 - Detect invalid properties in nodes
1048 - Sort the fdtmap by offset
1051 Simon Glass <sjg@chromium.org>