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Tom Rini83d290c2018-05-06 17:58:06 -04001# SPDX-License-Identifier: GPL-2.0+
Simon Glassbf7fd502016-11-25 20:15:51 -07002# Copyright (c) 2016 Google, Inc
Simon Glassbf7fd502016-11-25 20:15:51 -07003
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
Simon Glass9c0a8b12017-11-12 21:52:06 -0700207Enabling 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
Simon Glassbf7fd502016-11-25 20:15:51 -0700228Image 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 {
Simon Glass3ab95982018-08-01 15:22:37 -0600241 offset = <CONFIG_SPL_PAD_TO>;
Simon Glassbf7fd502016-11-25 20:15:51 -0700242 };
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
Simon Glass3ab95982018-08-01 15:22:37 -0600260specify the start offset of an entry using the 'offset' property.
Simon Glassbf7fd502016-11-25 20:15:51 -0700261
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
Simon Glass3ab95982018-08-01 15:22:37 -0600268offset:
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.
Simon Glassbf7fd502016-11-25 20:15:51 -0700274
275align:
Simon Glass3ab95982018-08-01 15:22:37 -0600276 This sets the alignment of the entry. The entry offset is adjusted
Simon Glassbf7fd502016-11-25 20:15:51 -0700277 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
Simon Glass844e5b22018-06-01 09:38:22 -0600306 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.
Simon Glassbf7fd502016-11-25 20:15:51 -0700309
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
Simon Glass3ab95982018-08-01 15:22:37 -0600320offset-unset:
321 Indicates that the offset of this entry should not be set by placing
Simon Glass258fb0e2018-06-01 09:38:17 -0600322 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
Simon Glass3ab95982018-08-01 15:22:37 -0600325 not set the offset (with the GetOffsets() method).
Simon Glass258fb0e2018-06-01 09:38:17 -0600326
Simon Glassdbf6be92018-08-01 15:22:42 -0600327image-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
Simon Glassbf7fd502016-11-25 20:15:51 -0700333
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
Simon Glass3ab95982018-08-01 15:22:37 -0600348 be positioned after the padding. This defaults to 0.
Simon Glassbf7fd502016-11-25 20:15:51 -0700349
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
Simon Glass3ab95982018-08-01 15:22:37 -0600361sort-by-offset:
Simon Glassbf7fd502016-11-25 20:15:51 -0700362 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
Simon Glass3ab95982018-08-01 15:22:37 -0600365 the 'offset' properties are set by CONFIG options, so their ordering is
Simon Glassbf7fd502016-11-25 20:15:51 -0700366 not known a priori.
367
368 This is a boolean property so needs no value. To enable it, add a
Simon Glass3ab95982018-08-01 15:22:37 -0600369 line 'sort-by-offset;' to your description.
Simon Glassbf7fd502016-11-25 20:15:51 -0700370
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:
Simon Glass3ab95982018-08-01 15:22:37 -0600393 For x86 machines the ROM offsets start just before 4GB and extend
Simon Glassbf7fd502016-11-25 20:15:51 -0700394 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
Simon Glass3ab95982018-08-01 15:22:37 -0600397 8MB ROM, the offset of the first entry would be 0xfff80000 with
Simon Glassbf7fd502016-11-25 20:15:51 -0700398 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
Simon Glassdd57c132018-06-01 09:38:11 -0600404It 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
Simon Glassbf7fd502016-11-25 20:15:51 -0700408
Simon Glass18546952018-06-01 09:38:16 -0600409Sections 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
Simon Glass7ae5f312018-06-01 09:38:19 -0600419is 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
Simon Glass18546952018-06-01 09:38:16 -0600421upgraded 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;
Simon Glassc8d48ef2018-06-01 09:38:21 -0600427 name-prefix = "ro-";
Simon Glass18546952018-06-01 09:38:16 -0600428 size = <0x100000>;
429 u-boot {
430 };
431 };
432 section@1 {
Simon Glassc8d48ef2018-06-01 09:38:21 -0600433 name-prefix = "rw-";
Simon Glass18546952018-06-01 09:38:16 -0600434 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
Simon Glassc8d48ef2018-06-01 09:38:21 -0600449name-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
Simon Glass18546952018-06-01 09:38:16 -0600455
Simon Glasse0ff8552016-11-25 20:15:53 -0700456Special properties
457------------------
458
459Some entries support special properties, documented here:
460
461u-boot-with-ucode-ptr:
462 optional-ucode: boolean property to make microcode optional. If the
463 u-boot.bin image does not include microcode, no error will
464 be generated.
465
466
Simon Glassbf7fd502016-11-25 20:15:51 -0700467Order of image creation
468-----------------------
469
470Image creation proceeds in the following order, for each entry in the image.
471
Simon Glass078ab1a2018-07-06 10:27:41 -06004721. AddMissingProperties() - binman can add calculated values to the device
Simon Glass3ab95982018-08-01 15:22:37 -0600473tree as part of its processing, for example the offset and size of each
Simon Glass078ab1a2018-07-06 10:27:41 -0600474entry. This method adds any properties associated with this, expanding the
475device tree as needed. These properties can have placeholder values which are
476set later by SetCalculatedProperties(). By that stage the size of sections
477cannot be changed (since it would cause the images to need to be repacked),
478but the correct values can be inserted.
479
4802. ProcessFdt() - process the device tree information as required by the
Simon Glassecab8972018-07-06 10:27:40 -0600481particular entry. This may involve adding or deleting properties. If the
482processing is complete, this method should return True. If the processing
483cannot complete because it needs the ProcessFdt() method of another entry to
484run first, this method should return False, in which case it will be called
485again later.
486
Simon Glass078ab1a2018-07-06 10:27:41 -06004873. GetEntryContents() - the contents of each entry are obtained, normally by
Simon Glassbf7fd502016-11-25 20:15:51 -0700488reading from a file. This calls the Entry.ObtainContents() to read the
489contents. The default version of Entry.ObtainContents() calls
490Entry.GetDefaultFilename() and then reads that file. So a common mechanism
491to select a file to read is to override that function in the subclass. The
492functions must return True when they have read the contents. Binman will
493retry calling the functions a few times if False is returned, allowing
494dependencies between the contents of different entries.
495
Simon Glass3ab95982018-08-01 15:22:37 -06004964. GetEntryOffsets() - calls Entry.GetOffsets() for each entry. This can
Simon Glassbf7fd502016-11-25 20:15:51 -0700497return a dict containing entries that need updating. The key should be the
Simon Glass3ab95982018-08-01 15:22:37 -0600498entry name and the value is a tuple (offset, size). This allows an entry to
499provide the offset and size for other entries. The default implementation
500of GetEntryOffsets() returns {}.
Simon Glassbf7fd502016-11-25 20:15:51 -0700501
Simon Glass3ab95982018-08-01 15:22:37 -06005025. PackEntries() - calls Entry.Pack() which figures out the offset and
503size of an entry. The 'current' image offset is passed in, and the function
504returns the offset immediately after the entry being packed. The default
Simon Glassbf7fd502016-11-25 20:15:51 -0700505implementation of Pack() is usually sufficient.
506
Simon Glass078ab1a2018-07-06 10:27:41 -06005076. CheckSize() - checks that the contents of all the entries fits within
Simon Glassbf7fd502016-11-25 20:15:51 -0700508the image size. If the image does not have a defined size, the size is set
509large enough to hold all the entries.
510
Simon Glass078ab1a2018-07-06 10:27:41 -06005117. CheckEntries() - checks that the entries do not overlap, nor extend
Simon Glassbf7fd502016-11-25 20:15:51 -0700512outside the image.
513
Simon Glass078ab1a2018-07-06 10:27:41 -06005148. SetCalculatedProperties() - update any calculated properties in the device
Simon Glass3ab95982018-08-01 15:22:37 -0600515tree. This sets the correct 'offset' and 'size' vaues, for example.
Simon Glass078ab1a2018-07-06 10:27:41 -0600516
5179. ProcessEntryContents() - this calls Entry.ProcessContents() on each entry.
Simon Glassbf7fd502016-11-25 20:15:51 -0700518The default implementatoin does nothing. This can be overriden to adjust the
519contents of an entry in some way. For example, it would be possible to create
520an entry containing a hash of the contents of some other entries. At this
Simon Glass3ab95982018-08-01 15:22:37 -0600521stage the offset and size of entries should not be adjusted.
Simon Glassbf7fd502016-11-25 20:15:51 -0700522
Simon Glass078ab1a2018-07-06 10:27:41 -060052310. WriteSymbols() - write the value of symbols into the U-Boot SPL binary.
Simon Glass3ab95982018-08-01 15:22:37 -0600524See 'Access to binman entry offsets at run time' below for a description of
Simon Glass0a4357c2018-07-06 10:27:39 -0600525what happens in this stage.
Simon Glass39c15022017-11-13 18:55:05 -0700526
Simon Glass078ab1a2018-07-06 10:27:41 -060052711. BuildImage() - builds the image and writes it to a file. This is the final
Simon Glassbf7fd502016-11-25 20:15:51 -0700528step.
529
530
Simon Glass6d427c62016-11-25 20:15:59 -0700531Automatic .dtsi inclusion
532-------------------------
533
534It is sometimes inconvenient to add a 'binman' node to the .dts file for each
535board. This can be done by using #include to bring in a common file. Another
536approach supported by the U-Boot build system is to automatically include
537a common header. You can then put the binman node (and anything else that is
538specific to U-Boot, such as u-boot,dm-pre-reloc properies) in that header
539file.
540
541Binman will search for the following files in arch/<arch>/dts:
542
543 <dts>-u-boot.dtsi where <dts> is the base name of the .dts file
544 <CONFIG_SYS_SOC>-u-boot.dtsi
545 <CONFIG_SYS_CPU>-u-boot.dtsi
546 <CONFIG_SYS_VENDOR>-u-boot.dtsi
547 u-boot.dtsi
548
549U-Boot will only use the first one that it finds. If you need to include a
550more general file you can do that from the more specific file using #include.
551If you are having trouble figuring out what is going on, you can uncomment
552the 'warning' line in scripts/Makefile.lib to see what it has found:
553
554 # Uncomment for debugging
Simon Glass511fd0b2017-11-12 21:52:05 -0700555 # This shows all the files that were considered and the one that we chose.
556 # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
Simon Glass6d427c62016-11-25 20:15:59 -0700557
558
Simon Glassdbf6be92018-08-01 15:22:42 -0600559Access to binman entry offsets at run time (symbols)
560----------------------------------------------------
Simon Glass39c15022017-11-13 18:55:05 -0700561
562Binman assembles images and determines where each entry is placed in the image.
563This information may be useful to U-Boot at run time. For example, in SPL it
564is useful to be able to find the location of U-Boot so that it can be executed
565when SPL is finished.
566
567Binman allows you to declare symbols in the SPL image which are filled in
568with their correct values during the build. For example:
569
Simon Glass3ab95982018-08-01 15:22:37 -0600570 binman_sym_declare(ulong, u_boot_any, offset);
Simon Glass39c15022017-11-13 18:55:05 -0700571
Simon Glass3ab95982018-08-01 15:22:37 -0600572declares a ulong value which will be assigned to the offset of any U-Boot
Simon Glass39c15022017-11-13 18:55:05 -0700573image (u-boot.bin, u-boot.img, u-boot-nodtb.bin) that is present in the image.
574You can access this value with something like:
575
Simon Glass3ab95982018-08-01 15:22:37 -0600576 ulong u_boot_offset = binman_sym(ulong, u_boot_any, offset);
Simon Glass39c15022017-11-13 18:55:05 -0700577
Simon Glass3ab95982018-08-01 15:22:37 -0600578Thus u_boot_offset will be set to the offset of U-Boot in memory, assuming that
Simon Glass39c15022017-11-13 18:55:05 -0700579the whole image has been loaded, or is available in flash. You can then jump to
580that address to start U-Boot.
581
582At present this feature is only supported in SPL. In principle it is possible
583to fill in such symbols in U-Boot proper, as well.
584
585
Simon Glassdbf6be92018-08-01 15:22:42 -0600586Access to binman entry offsets at run time (fdt)
587------------------------------------------------
588
589Binman can update the U-Boot FDT to include the final position and size of
590each entry in the images it processes. The option to enable this is -u and it
591causes binman to make sure that the 'offset', 'image-pos' and 'size' properties
592are set correctly for every entry. Since it is not necessary to specify these in
593the image definition, binman calculates the final values and writes these to
594the device tree. These can be used by U-Boot at run-time to find the location
595of each entry.
596
597
Simon Glass3b0c38212018-06-01 09:38:20 -0600598Map files
599---------
600
601The -m option causes binman to output a .map file for each image that it
Simon Glass3ab95982018-08-01 15:22:37 -0600602generates. This shows the offset and size of each entry. For example:
Simon Glass3b0c38212018-06-01 09:38:20 -0600603
Simon Glass3ab95982018-08-01 15:22:37 -0600604 Offset Size Name
Simon Glass8122f392018-07-17 13:25:28 -0600605 00000000 00000028 main-section
606 00000000 00000010 section@0
607 00000000 00000004 u-boot
608 00000010 00000010 section@1
609 00000000 00000004 u-boot
Simon Glass3b0c38212018-06-01 09:38:20 -0600610
611This shows a hierarchical image with two sections, each with a single entry. The
Simon Glass3ab95982018-08-01 15:22:37 -0600612offsets of the sections are absolute hex byte offsets within the image. The
613offsets of the entries are relative to their respective sections. The size of
Simon Glass3b0c38212018-06-01 09:38:20 -0600614each entry is also shown, in bytes (hex). The indentation shows the entries
615nested inside their sections.
616
617
Simon Glass53af22a2018-07-17 13:25:32 -0600618Passing command-line arguments to entries
619-----------------------------------------
620
621Sometimes it is useful to pass binman the value of an entry property from the
622command line. For example some entries need access to files and it is not
623always convenient to put these filenames in the image definition (device tree).
624
625The-a option supports this:
626
627 -a<prop>=<value>
628
629where
630
631 <prop> is the property to set
632 <value> is the value to set it to
633
634Not all properties can be provided this way. Only some entries support it,
635typically for filenames.
636
637
Simon Glass6d427c62016-11-25 20:15:59 -0700638Code coverage
639-------------
640
641Binman is a critical tool and is designed to be very testable. Entry
642implementations target 100% test coverage. Run 'binman -T' to check this.
643
644To enable Python test coverage on Debian-type distributions (e.g. Ubuntu):
645
Tom Rini16d836c2018-07-06 10:27:14 -0600646 $ sudo apt-get install python-coverage python-pytest
Simon Glass6d427c62016-11-25 20:15:59 -0700647
648
Simon Glassbf7fd502016-11-25 20:15:51 -0700649Advanced Features / Technical docs
650----------------------------------
651
652The behaviour of entries is defined by the Entry class. All other entries are
653a subclass of this. An important subclass is Entry_blob which takes binary
654data from a file and places it in the entry. In fact most entry types are
655subclasses of Entry_blob.
656
657Each entry type is a separate file in the tools/binman/etype directory. Each
658file contains a class called Entry_<type> where <type> is the entry type.
659New entry types can be supported by adding new files in that directory.
660These will automatically be detected by binman when needed.
661
662Entry properties are documented in entry.py. The entry subclasses are free
663to change the values of properties to support special behaviour. For example,
664when Entry_blob loads a file, it sets content_size to the size of the file.
665Entry classes can adjust other entries. For example, an entry that knows
Simon Glass3ab95982018-08-01 15:22:37 -0600666where other entries should be positioned can set up those entries' offsets
Simon Glassbf7fd502016-11-25 20:15:51 -0700667so they don't need to be set in the binman decription. It can also adjust
668entry contents.
669
670Most of the time such essoteric behaviour is not needed, but it can be
671essential for complex images.
672
Simon Glass3ed0de32017-12-24 12:12:07 -0700673If you need to specify a particular device-tree compiler to use, you can define
674the DTC environment variable. This can be useful when the system dtc is too
675old.
676
Simon Glassbf7fd502016-11-25 20:15:51 -0700677
678History / Credits
679-----------------
680
681Binman takes a lot of inspiration from a Chrome OS tool called
682'cros_bundle_firmware', which I wrote some years ago. That tool was based on
683a reasonably simple and sound design but has expanded greatly over the
684years. In particular its handling of x86 images is convoluted.
685
Simon Glass7ae5f312018-06-01 09:38:19 -0600686Quite a few lessons have been learned which are hopefully applied here.
Simon Glassbf7fd502016-11-25 20:15:51 -0700687
688
689Design notes
690------------
691
692On the face of it, a tool to create firmware images should be fairly simple:
693just find all the input binaries and place them at the right place in the
694image. The difficulty comes from the wide variety of input types (simple
695flat binaries containing code, packaged data with various headers), packing
696requirments (alignment, spacing, device boundaries) and other required
697features such as hierarchical images.
698
699The design challenge is to make it easy to create simple images, while
700allowing the more complex cases to be supported. For example, for most
701images we don't much care exactly where each binary ends up, so we should
702not have to specify that unnecessarily.
703
704New entry types should aim to provide simple usage where possible. If new
705core features are needed, they can be added in the Entry base class.
706
707
708To do
709-----
710
711Some ideas:
Simon Glassbf7fd502016-11-25 20:15:51 -0700712- Use of-platdata to make the information available to code that is unable
713 to use device tree (such as a very small SPL image)
Simon Glassbf7fd502016-11-25 20:15:51 -0700714- Allow easy building of images by specifying just the board name
Simon Glass16b8d6b2018-07-06 10:27:42 -0600715- Produce a full Python binding for libfdt (for upstream). This is nearing
716 completion but some work remains
Simon Glassbf7fd502016-11-25 20:15:51 -0700717- Add an option to decode an image into the constituent binaries
Simon Glassbf7fd502016-11-25 20:15:51 -0700718- Support building an image for a board (-b) more completely, with a
719 configurable build directory
720- Consider making binman work with buildman, although if it is used in the
721 Makefile, this will be automatic
Simon Glassbf7fd502016-11-25 20:15:51 -0700722
723--
724Simon Glass <sjg@chromium.org>
7257/7/2016