xref: /openbmc/u-boot/tools/binman/README (revision 73e4ba98)
1# SPDX-License-Identifier: GPL-2.0+
2# Copyright (c) 2016 Google, Inc
3
4Introduction
5------------
6
7Firmware often consists of several components which must be packaged together.
8For example, we may have SPL, U-Boot, a device tree and an environment area
9grouped together and placed in MMC flash. When the system starts, it must be
10able to find these pieces.
11
12So far U-Boot has not provided a way to handle creating such images in a
13general way. Each SoC does what it needs to build an image, often packing or
14concatenating images in the U-Boot build system.
15
16Binman aims to provide a mechanism for building images, from simple
17SPL + U-Boot combinations, to more complex arrangements with many parts.
18
19
20What it does
21------------
22
23Binman reads your board's device tree and finds a node which describes the
24required image layout. It uses this to work out what to place where. The
25output file normally contains the device tree, so it is in principle possible
26to read an image and extract its constituent parts.
27
28
29Features
30--------
31
32So 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
34place entries at a fixed location in the image, or fit them together with
35suitable padding and alignment. It provides a way to process binaries before
36they are included, by adding a Python plug-in. The device tree is available
37to U-Boot at run-time so that the images can be interpreted.
38
39Binman does not yet update the device tree with the final location of
40everything when it is done. A simple C structure could be generated for
41constrained environments like SPL (using dtoc) but this is also not
42implemented.
43
44Binman can also support incorporating filesystems in the image if required.
45For example x86 platforms may use CBFS in some cases.
46
47Binman is intended for use with U-Boot but is designed to be general enough
48to be useful in other image-packaging situations.
49
50
51Motivation
52----------
53
54Packaging of firmware is quite a different task from building the various
55parts. In many cases the various binaries which go into the image come from
56separate build systems. For example, ARM Trusted Firmware is used on ARMv8
57devices but is not built in the U-Boot tree. If a Linux kernel is included
58in the firmware image, it is built elsewhere.
59
60It is of course possible to add more and more build rules to the U-Boot
61build system to cover these cases. It can shell out to other Makefiles and
62build scripts. But it seems better to create a clear divide between building
63software and packaging it.
64
65At present this is handled by manual instructions, different for each board,
66on how to create images that will boot. By turning these instructions into a
67standard format, we can support making valid images for any board without
68manual effort, lots of READMEs, etc.
69
70Benefits:
71- Each binary can have its own build system and tool chain without creating
72any dependencies between them
73- Avoids the need for a single-shot build: individual parts can be updated
74and brought in as needed
75- Provides for a standard image description available in the build and at
76run-time
77- SoC-specific image-signing tools can be accomodated
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,
80SPL. It can be made available to other software also
81- The image description is easily readable (it's a text file in device-tree
82format) and permits flexible packing of binaries
83
84
85Terminology
86-----------
87
88Binman uses the following terms:
89
90- image - an output file containing a firmware image
91- binary - an input binary that goes into the image
92
93
94Relationship to FIT
95-------------------
96
97FIT is U-Boot's official image format. It supports multiple binaries with
98load / execution addresses, compression. It also supports verification
99through hashing and RSA signatures.
100
101FIT was originally designed to support booting a Linux kernel (with an
102optional ramdisk) and device tree chosen from various options in the FIT.
103Now that U-Boot supports configuration via device tree, it is possible to
104load U-Boot from a FIT, with the device tree chosen by SPL.
105
106Binman considers FIT to be one of the binaries it can place in the image.
107
108Where possible it is best to put as much as possible in the FIT, with binman
109used to deal with cases not covered by FIT. Examples include initial
110execution (since FIT itself does not have an executable header) and dealing
111with device boundaries, such as the read-only/read-write separation in SPI
112flash.
113
114For U-Boot, binman should not be used to create ad-hoc images in place of
115FIT.
116
117
118Relationship to mkimage
119-----------------------
120
121The mkimage tool provides a means to create a FIT. Traditionally it has
122needed an image description file: a device tree, like binman, but in a
123different format. More recently it has started to support a '-f auto' mode
124which can generate that automatically.
125
126More relevant to binman, mkimage also permits creation of many SoC-specific
127image types. These can be listed by running 'mkimage -T list'. Examples
128include 'rksd', the Rockchip SD/MMC boot format. The mkimage tool is often
129called from the U-Boot build system for this reason.
130
131Binman considers the output files created by mkimage to be binary blobs
132which it can place in an image. Binman does not replace the mkimage tool or
133this purpose. It would be possible in some situtions to create a new entry
134type for the images in mkimage, but this would not add functionality. It
135seems better to use the mkiamge tool to generate binaries and avoid blurring
136the boundaries between building input files (mkimage) and packaging then
137into a final image (binman).
138
139
140Example use of binman in U-Boot
141-------------------------------
142
143Binman aims to replace some of the ad-hoc image creation in the U-Boot
144build system.
145
146Consider sunxi. It has the following steps:
147
1481. It uses a custom mksunxiboot tool to build an SPL image called
149sunxi-spl.bin. This should probably move into mkimage.
150
1512. It uses mkimage to package U-Boot into a legacy image file (so that it can
152hold the load and execution address) called u-boot.img.
153
1543. It builds a final output image called u-boot-sunxi-with-spl.bin which
155consists of sunxi-spl.bin, some padding and u-boot.img.
156
157Binman is intended to replace the last step. The U-Boot build system builds
158u-boot.bin and sunxi-spl.bin. Binman can then take over creation of
159sunxi-spl.bin (by calling mksunxiboot, or hopefully one day mkimage). In any
160case, it would then create the image from the component parts.
161
162This simplifies the U-Boot Makefile somewhat, since various pieces of logic
163can be replaced by a call to binman.
164
165
166Example use of binman for x86
167-----------------------------
168
169In most cases x86 images have a lot of binary blobs, 'black-box' code
170provided by Intel which must be run for the platform to work. Typically
171these blobs are not relocatable and must be placed at fixed areas in the
172firmare image.
173
174Currently this is handled by ifdtool, which places microcode, FSP, MRC, VGA
175BIOS, reference code and Intel ME binaries into a u-boot.rom file.
176
177Binman is intended to replace all of this, with ifdtool left to handle only
178the configuration of the Intel-format descriptor.
179
180
181Running binman
182--------------
183
184Type:
185
186	binman -b <board_name>
187
188to build an image for a board. The board name is the same name used when
189configuring U-Boot (e.g. for sandbox_defconfig the board name is 'sandbox').
190Binman assumes that the input files for the build are in ../b/<board_name>.
191
192Or you can specify this explicitly:
193
194	binman -I <build_path>
195
196where <build_path> is the build directory containing the output of the U-Boot
197build.
198
199(Future work will make this more configurable)
200
201In either case, binman picks up the device tree file (u-boot.dtb) and looks
202for its instructions in the 'binman' node.
203
204Binman has a few other options which you can see by running 'binman -h'.
205
206
207Enabling binman for a board
208---------------------------
209
210At present binman is invoked from a rule in the main Makefile. Typically you
211will have a rule like:
212
213ifneq ($(CONFIG_ARCH_<something>),)
214u-boot-<your_suffix>.bin: <input_file_1> <input_file_2> checkbinman FORCE
215	$(call if_changed,binman)
216endif
217
218This assumes that u-boot-<your_suffix>.bin is a target, and is the final file
219that you need to produce. You can make it a target by adding it to ALL-y
220either in the main Makefile or in a config.mk file in your arch subdirectory.
221
222Once binman is executed it will pick up its instructions from a device-tree
223file, typically <soc>-u-boot.dtsi, where <soc> is your CONFIG_SYS_SOC value.
224You can use other, more specific CONFIG options - see 'Automatic .dtsi
225inclusion' below.
226
227
228Image description format
229------------------------
230
231The binman node is called 'binman'. An example image description is shown
232below:
233
234	binman {
235		filename = "u-boot-sunxi-with-spl.bin";
236		pad-byte = <0xff>;
237		blob {
238			filename = "spl/sunxi-spl.bin";
239		};
240		u-boot {
241			offset = <CONFIG_SPL_PAD_TO>;
242		};
243	};
244
245
246This requests binman to create an image file called u-boot-sunxi-with-spl.bin
247consisting of a specially formatted SPL (spl/sunxi-spl.bin, built by the
248normal U-Boot Makefile), some 0xff padding, and a U-Boot legacy image. The
249padding comes from the fact that the second binary is placed at
250CONFIG_SPL_PAD_TO. If that line were omitted then the U-Boot binary would
251immediately follow the SPL binary.
252
253The binman node describes an image. The sub-nodes describe entries in the
254image. Each entry represents a region within the overall image. The name of
255the entry (blob, u-boot) tells binman what to put there. For 'blob' we must
256provide a filename. For 'u-boot', binman knows that this means 'u-boot.bin'.
257
258Entries are normally placed into the image sequentially, one after the other.
259The image size is the total size of all entries. As you can see, you can
260specify the start offset of an entry using the 'offset' property.
261
262Note that due to a device tree requirement, all entries must have a unique
263name. If you want to put the same binary in the image multiple times, you can
264use any unique name, with the 'type' property providing the type.
265
266The attributes supported for entries are described below.
267
268offset:
269	This sets the offset of an entry within the image or section containing
270	it. The first byte of the image is normally at offset 0. If 'offset' is
271	not provided, binman sets it to the end of the previous region, or the
272	start of the image's entry area (normally 0) if there is no previous
273	region.
274
275align:
276	This sets the alignment of the entry. The entry offset is adjusted
277	so that the entry starts on an aligned boundary within the image. For
278	example 'align = <16>' means that the entry will start on a 16-byte
279	boundary. Alignment shold be a power of 2. If 'align' is not
280	provided, no alignment is performed.
281
282size:
283	This sets the size of the entry. The contents will be padded out to
284	this size. If this is not provided, it will be set to the size of the
285	contents.
286
287pad-before:
288	Padding before the contents of the entry. Normally this is 0, meaning
289	that the contents start at the beginning of the entry. This can be
290	offset the entry contents a little. Defaults to 0.
291
292pad-after:
293	Padding after the contents of the entry. Normally this is 0, meaning
294	that the entry ends at the last byte of content (unless adjusted by
295	other properties). This allows room to be created in the image for
296	this entry to expand later. Defaults to 0.
297
298align-size:
299	This sets the alignment of the entry size. For example, to ensure
300	that the size of an entry is a multiple of 64 bytes, set this to 64.
301	If 'align-size' is not provided, no alignment is performed.
302
303align-end:
304	This sets the alignment of the end of an entry. Some entries require
305	that they end on an alignment boundary, regardless of where they
306	start. This does not move the start of the entry, so the contents of
307	the entry will still start at the beginning. But there may be padding
308	at the end. If 'align-end' is not provided, no alignment is performed.
309
310filename:
311	For 'blob' types this provides the filename containing the binary to
312	put into the entry. If binman knows about the entry type (like
313	u-boot-bin), then there is no need to specify this.
314
315type:
316	Sets the type of an entry. This defaults to the entry name, but it is
317	possible to use any name, and then add (for example) 'type = "u-boot"'
318	to specify the type.
319
320offset-unset:
321	Indicates that the offset of this entry should not be set by placing
322	it immediately after the entry before. Instead, is set by another
323	entry which knows where this entry should go. When this boolean
324	property is present, binman will give an error if another entry does
325	not set the offset (with the GetOffsets() method).
326
327image-pos:
328	This cannot be set on entry (or at least it is ignored if it is), but
329	with the -u option, binman will set it to the absolute image position
330	for each entry. This makes it easy to find out exactly where the entry
331	ended up in the image, regardless of parent sections, etc.
332
333
334The attributes supported for images are described below. Several are similar
335to those for entries.
336
337size:
338	Sets the image size in bytes, for example 'size = <0x100000>' for a
339	1MB image.
340
341align-size:
342	This sets the alignment of the image size. For example, to ensure
343	that the image ends on a 512-byte boundary, use 'align-size = <512>'.
344	If 'align-size' is not provided, no alignment is performed.
345
346pad-before:
347	This sets the padding before the image entries. The first entry will
348	be positioned after the padding. This defaults to 0.
349
350pad-after:
351	This sets the padding after the image entries. The padding will be
352	placed after the last entry. This defaults to 0.
353
354pad-byte:
355	This specifies the pad byte to use when padding in the image. It
356	defaults to 0. To use 0xff, you would add 'pad-byte = <0xff>'.
357
358filename:
359	This specifies the image filename. It defaults to 'image.bin'.
360
361sort-by-offset:
362	This causes binman to reorder the entries as needed to make sure they
363	are in increasing positional order. This can be used when your entry
364	order may not match the positional order. A common situation is where
365	the 'offset' properties are set by CONFIG options, so their ordering is
366	not known a priori.
367
368	This is a boolean property so needs no value. To enable it, add a
369	line 'sort-by-offset;' to your description.
370
371multiple-images:
372	Normally only a single image is generated. To create more than one
373	image, put this property in the binman node. For example, this will
374	create image1.bin containing u-boot.bin, and image2.bin containing
375	both spl/u-boot-spl.bin and u-boot.bin:
376
377	binman {
378		multiple-images;
379		image1 {
380			u-boot {
381			};
382		};
383
384		image2 {
385			spl {
386			};
387			u-boot {
388			};
389		};
390	};
391
392end-at-4gb:
393	For x86 machines the ROM offsets start just before 4GB and extend
394	up so that the image finished at the 4GB boundary. This boolean
395	option can be enabled to support this. The image size must be
396	provided so that binman knows when the image should start. For an
397	8MB ROM, the offset of the first entry would be 0xfff80000 with
398	this option, instead of 0 without this option.
399
400
401Examples of the above options can be found in the tests. See the
402tools/binman/test directory.
403
404It is possible to have the same binary appear multiple times in the image,
405either by using a unit number suffix (u-boot@0, u-boot@1) or by using a
406different name for each and specifying the type with the 'type' attribute.
407
408
409Sections and hiearchical images
410-------------------------------
411
412Sometimes it is convenient to split an image into several pieces, each of which
413contains its own set of binaries. An example is a flash device where part of
414the image is read-only and part is read-write. We can set up sections for each
415of these, and place binaries in them independently. The image is still produced
416as a single output file.
417
418This feature provides a way of creating hierarchical images. For example here
419is an example image with two copies of U-Boot. One is read-only (ro), intended
420to be written only in the factory. Another is read-write (rw), so that it can be
421upgraded in the field. The sizes are fixed so that the ro/rw boundary is known
422and can be programmed:
423
424	binman {
425		section@0 {
426			read-only;
427			name-prefix = "ro-";
428			size = <0x100000>;
429			u-boot {
430			};
431		};
432		section@1 {
433			name-prefix = "rw-";
434			size = <0x100000>;
435			u-boot {
436			};
437		};
438	};
439
440This image could be placed into a SPI flash chip, with the protection boundary
441set at 1MB.
442
443A few special properties are provided for sections:
444
445read-only:
446	Indicates that this section is read-only. This has no impact on binman's
447	operation, but his property can be read at run time.
448
449name-prefix:
450	This string is prepended to all the names of the binaries in the
451	section. In the example above, the 'u-boot' binaries which actually be
452	renamed to 'ro-u-boot' and 'rw-u-boot'. This can be useful to
453	distinguish binaries with otherwise identical names.
454
455
456Entry Documentation
457-------------------
458
459For details on the various entry types supported by binman and how to use them,
460see README.entries. This is generated from the source code using:
461
462	binman -E >tools/binman/README.entries
463
464
465Special properties
466------------------
467
468Some entries support special properties, documented here:
469
470u-boot-with-ucode-ptr:
471	optional-ucode: boolean property to make microcode optional. If the
472		u-boot.bin image does not include microcode, no error will
473		be generated.
474
475
476Order of image creation
477-----------------------
478
479Image creation proceeds in the following order, for each entry in the image.
480
4811. AddMissingProperties() - binman can add calculated values to the device
482tree as part of its processing, for example the offset and size of each
483entry. This method adds any properties associated with this, expanding the
484device tree as needed. These properties can have placeholder values which are
485set later by SetCalculatedProperties(). By that stage the size of sections
486cannot be changed (since it would cause the images to need to be repacked),
487but the correct values can be inserted.
488
4892. ProcessFdt() - process the device tree information as required by the
490particular entry. This may involve adding or deleting properties. If the
491processing is complete, this method should return True. If the processing
492cannot complete because it needs the ProcessFdt() method of another entry to
493run first, this method should return False, in which case it will be called
494again later.
495
4963. GetEntryContents() - the contents of each entry are obtained, normally by
497reading from a file. This calls the Entry.ObtainContents() to read the
498contents. The default version of Entry.ObtainContents() calls
499Entry.GetDefaultFilename() and then reads that file. So a common mechanism
500to select a file to read is to override that function in the subclass. The
501functions must return True when they have read the contents. Binman will
502retry calling the functions a few times if False is returned, allowing
503dependencies between the contents of different entries.
504
5054. GetEntryOffsets() - calls Entry.GetOffsets() for each entry. This can
506return a dict containing entries that need updating. The key should be the
507entry name and the value is a tuple (offset, size). This allows an entry to
508provide the offset and size for other entries. The default implementation
509of GetEntryOffsets() returns {}.
510
5115. PackEntries() - calls Entry.Pack() which figures out the offset and
512size of an entry. The 'current' image offset is passed in, and the function
513returns the offset immediately after the entry being packed. The default
514implementation of Pack() is usually sufficient.
515
5166. CheckSize() - checks that the contents of all the entries fits within
517the image size. If the image does not have a defined size, the size is set
518large enough to hold all the entries.
519
5207. CheckEntries() - checks that the entries do not overlap, nor extend
521outside the image.
522
5238. SetCalculatedProperties() - update any calculated properties in the device
524tree. This sets the correct 'offset' and 'size' vaues, for example.
525
5269. ProcessEntryContents() - this calls Entry.ProcessContents() on each entry.
527The default implementatoin does nothing. This can be overriden to adjust the
528contents of an entry in some way. For example, it would be possible to create
529an entry containing a hash of the contents of some other entries. At this
530stage the offset and size of entries should not be adjusted.
531
53210. WriteSymbols() - write the value of symbols into the U-Boot SPL binary.
533See 'Access to binman entry offsets at run time' below for a description of
534what happens in this stage.
535
53611. BuildImage() - builds the image and writes it to a file. This is the final
537step.
538
539
540Automatic .dtsi inclusion
541-------------------------
542
543It is sometimes inconvenient to add a 'binman' node to the .dts file for each
544board. This can be done by using #include to bring in a common file. Another
545approach supported by the U-Boot build system is to automatically include
546a common header. You can then put the binman node (and anything else that is
547specific to U-Boot, such as u-boot,dm-pre-reloc properies) in that header
548file.
549
550Binman will search for the following files in arch/<arch>/dts:
551
552   <dts>-u-boot.dtsi where <dts> is the base name of the .dts file
553   <CONFIG_SYS_SOC>-u-boot.dtsi
554   <CONFIG_SYS_CPU>-u-boot.dtsi
555   <CONFIG_SYS_VENDOR>-u-boot.dtsi
556   u-boot.dtsi
557
558U-Boot will only use the first one that it finds. If you need to include a
559more general file you can do that from the more specific file using #include.
560If you are having trouble figuring out what is going on, you can uncomment
561the 'warning' line in scripts/Makefile.lib to see what it has found:
562
563   # Uncomment for debugging
564   # This shows all the files that were considered and the one that we chose.
565   # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
566
567
568Access to binman entry offsets at run time (symbols)
569----------------------------------------------------
570
571Binman assembles images and determines where each entry is placed in the image.
572This information may be useful to U-Boot at run time. For example, in SPL it
573is useful to be able to find the location of U-Boot so that it can be executed
574when SPL is finished.
575
576Binman allows you to declare symbols in the SPL image which are filled in
577with their correct values during the build. For example:
578
579    binman_sym_declare(ulong, u_boot_any, offset);
580
581declares a ulong value which will be assigned to the offset of any U-Boot
582image (u-boot.bin, u-boot.img, u-boot-nodtb.bin) that is present in the image.
583You can access this value with something like:
584
585    ulong u_boot_offset = binman_sym(ulong, u_boot_any, offset);
586
587Thus u_boot_offset will be set to the offset of U-Boot in memory, assuming that
588the whole image has been loaded, or is available in flash. You can then jump to
589that address to start U-Boot.
590
591At present this feature is only supported in SPL. In principle it is possible
592to fill in such symbols in U-Boot proper, as well.
593
594
595Access to binman entry offsets at run time (fdt)
596------------------------------------------------
597
598Binman can update the U-Boot FDT to include the final position and size of
599each entry in the images it processes. The option to enable this is -u and it
600causes binman to make sure that the 'offset', 'image-pos' and 'size' properties
601are set correctly for every entry. Since it is not necessary to specify these in
602the image definition, binman calculates the final values and writes these to
603the device tree. These can be used by U-Boot at run-time to find the location
604of each entry.
605
606
607Map files
608---------
609
610The -m option causes binman to output a .map file for each image that it
611generates. This shows the offset and size of each entry. For example:
612
613      Offset      Size  Name
614    00000000  00000028  main-section
615     00000000  00000010  section@0
616      00000000  00000004  u-boot
617     00000010  00000010  section@1
618      00000000  00000004  u-boot
619
620This shows a hierarchical image with two sections, each with a single entry. The
621offsets of the sections are absolute hex byte offsets within the image. The
622offsets of the entries are relative to their respective sections. The size of
623each entry is also shown, in bytes (hex). The indentation shows the entries
624nested inside their sections.
625
626
627Passing command-line arguments to entries
628-----------------------------------------
629
630Sometimes it is useful to pass binman the value of an entry property from the
631command line. For example some entries need access to files and it is not
632always convenient to put these filenames in the image definition (device tree).
633
634The-a option supports this:
635
636    -a<prop>=<value>
637
638where
639
640    <prop> is the property to set
641    <value> is the value to set it to
642
643Not all properties can be provided this way. Only some entries support it,
644typically for filenames.
645
646
647Code coverage
648-------------
649
650Binman is a critical tool and is designed to be very testable. Entry
651implementations target 100% test coverage. Run 'binman -T' to check this.
652
653To enable Python test coverage on Debian-type distributions (e.g. Ubuntu):
654
655   $ sudo apt-get install python-coverage python-pytest
656
657
658Advanced Features / Technical docs
659----------------------------------
660
661The behaviour of entries is defined by the Entry class. All other entries are
662a subclass of this. An important subclass is Entry_blob which takes binary
663data from a file and places it in the entry. In fact most entry types are
664subclasses of Entry_blob.
665
666Each entry type is a separate file in the tools/binman/etype directory. Each
667file contains a class called Entry_<type> where <type> is the entry type.
668New entry types can be supported by adding new files in that directory.
669These will automatically be detected by binman when needed.
670
671Entry properties are documented in entry.py. The entry subclasses are free
672to change the values of properties to support special behaviour. For example,
673when Entry_blob loads a file, it sets content_size to the size of the file.
674Entry classes can adjust other entries. For example, an entry that knows
675where other entries should be positioned can set up those entries' offsets
676so they don't need to be set in the binman decription. It can also adjust
677entry contents.
678
679Most of the time such essoteric behaviour is not needed, but it can be
680essential for complex images.
681
682If you need to specify a particular device-tree compiler to use, you can define
683the DTC environment variable. This can be useful when the system dtc is too
684old.
685
686
687History / Credits
688-----------------
689
690Binman takes a lot of inspiration from a Chrome OS tool called
691'cros_bundle_firmware', which I wrote some years ago. That tool was based on
692a reasonably simple and sound design but has expanded greatly over the
693years. In particular its handling of x86 images is convoluted.
694
695Quite a few lessons have been learned which are hopefully applied here.
696
697
698Design notes
699------------
700
701On the face of it, a tool to create firmware images should be fairly simple:
702just find all the input binaries and place them at the right place in the
703image. The difficulty comes from the wide variety of input types (simple
704flat binaries containing code, packaged data with various headers), packing
705requirments (alignment, spacing, device boundaries) and other required
706features such as hierarchical images.
707
708The design challenge is to make it easy to create simple images, while
709allowing the more complex cases to be supported. For example, for most
710images we don't much care exactly where each binary ends up, so we should
711not have to specify that unnecessarily.
712
713New entry types should aim to provide simple usage where possible. If new
714core features are needed, they can be added in the Entry base class.
715
716
717To do
718-----
719
720Some ideas:
721- Use of-platdata to make the information available to code that is unable
722  to use device tree (such as a very small SPL image)
723- Allow easy building of images by specifying just the board name
724- Produce a full Python binding for libfdt (for upstream). This is nearing
725    completion but some work remains
726- Add an option to decode an image into the constituent binaries
727- Support building an image for a board (-b) more completely, with a
728  configurable build directory
729- Consider making binman work with buildman, although if it is used in the
730  Makefile, this will be automatic
731
732--
733Simon Glass <sjg@chromium.org>
7347/7/2016
735