xref: /openbmc/u-boot/tools/binman/README.entries (revision 0a98b28b)
1Binman Entry Documentation
2===========================
3
4This file describes the entry types supported by binman. These entry types can
5be placed in an image one by one to build up a final firmware image. It is
6fairly easy to create new entry types. Just add a new file to the 'etype'
7directory. You can use the existing entries as examples.
8
9Note that some entries are subclasses of others, using and extending their
10features to produce new behaviours.
11
12
13
14Entry: blob: Entry containing an arbitrary binary blob
15------------------------------------------------------
16
17Note: This should not be used by itself. It is normally used as a parent
18class by other entry types.
19
20Properties / Entry arguments:
21    - filename: Filename of file to read into entry
22    - compress: Compression algorithm to use:
23        none: No compression
24        lz4: Use lz4 compression (via 'lz4' command-line utility)
25
26This entry reads data from a file and places it in the entry. The
27default filename is often specified specified by the subclass. See for
28example the 'u_boot' entry which provides the filename 'u-boot.bin'.
29
30If compression is enabled, an extra 'uncomp-size' property is written to
31the node (if enabled with -u) which provides the uncompressed size of the
32data.
33
34
35
36Entry: blob-dtb: A blob that holds a device tree
37------------------------------------------------
38
39This is a blob containing a device tree. The contents of the blob are
40obtained from the list of available device-tree files, managed by the
41'state' module.
42
43
44
45Entry: blob-named-by-arg: A blob entry which gets its filename property from its subclass
46-----------------------------------------------------------------------------------------
47
48Properties / Entry arguments:
49    - <xxx>-path: Filename containing the contents of this entry (optional,
50        defaults to 0)
51
52where <xxx> is the blob_fname argument to the constructor.
53
54This entry cannot be used directly. Instead, it is used as a parent class
55for another entry, which defined blob_fname. This parameter is used to
56set the entry-arg or property containing the filename. The entry-arg or
57property is in turn used to set the actual filename.
58
59See cros_ec_rw for an example of this.
60
61
62
63Entry: cros-ec-rw: A blob entry which contains a Chromium OS read-write EC image
64--------------------------------------------------------------------------------
65
66Properties / Entry arguments:
67    - cros-ec-rw-path: Filename containing the EC image
68
69This entry holds a Chromium OS EC (embedded controller) image, for use in
70updating the EC on startup via software sync.
71
72
73
74Entry: files: Entry containing a set of files
75---------------------------------------------
76
77Properties / Entry arguments:
78    - pattern: Filename pattern to match the files to include
79    - compress: Compression algorithm to use:
80        none: No compression
81        lz4: Use lz4 compression (via 'lz4' command-line utility)
82
83This entry reads a number of files and places each in a separate sub-entry
84within this entry. To access these you need to enable device-tree updates
85at run-time so you can obtain the file positions.
86
87
88
89Entry: fill: An entry which is filled to a particular byte value
90----------------------------------------------------------------
91
92Properties / Entry arguments:
93    - fill-byte: Byte to use to fill the entry
94
95Note that the size property must be set since otherwise this entry does not
96know how large it should be.
97
98You can often achieve the same effect using the pad-byte property of the
99overall image, in that the space between entries will then be padded with
100that byte. But this entry is sometimes useful for explicitly setting the
101byte value of a region.
102
103
104
105Entry: fmap: An entry which contains an Fmap section
106----------------------------------------------------
107
108Properties / Entry arguments:
109    None
110
111FMAP is a simple format used by flashrom, an open-source utility for
112reading and writing the SPI flash, typically on x86 CPUs. The format
113provides flashrom with a list of areas, so it knows what it in the flash.
114It can then read or write just a single area, instead of the whole flash.
115
116The format is defined by the flashrom project, in the file lib/fmap.h -
117see www.flashrom.org/Flashrom for more information.
118
119When used, this entry will be populated with an FMAP which reflects the
120entries in the current image. Note that any hierarchy is squashed, since
121FMAP does not support this.
122
123
124
125Entry: gbb: An entry which contains a Chromium OS Google Binary Block
126---------------------------------------------------------------------
127
128Properties / Entry arguments:
129    - hardware-id: Hardware ID to use for this build (a string)
130    - keydir: Directory containing the public keys to use
131    - bmpblk: Filename containing images used by recovery
132
133Chromium OS uses a GBB to store various pieces of information, in particular
134the root and recovery keys that are used to verify the boot process. Some
135more details are here:
136
137    https://www.chromium.org/chromium-os/firmware-porting-guide/2-concepts
138
139but note that the page dates from 2013 so is quite out of date. See
140README.chromium for how to obtain the required keys and tools.
141
142
143
144Entry: intel-cmc: Entry containing an Intel Chipset Micro Code (CMC) file
145-------------------------------------------------------------------------
146
147Properties / Entry arguments:
148    - filename: Filename of file to read into entry
149
150This file contains microcode for some devices in a special format. An
151example filename is 'Microcode/C0_22211.BIN'.
152
153See README.x86 for information about x86 binary blobs.
154
155
156
157Entry: intel-descriptor: Intel flash descriptor block (4KB)
158-----------------------------------------------------------
159
160Properties / Entry arguments:
161    filename: Filename of file containing the descriptor. This is typically
162        a 4KB binary file, sometimes called 'descriptor.bin'
163
164This entry is placed at the start of flash and provides information about
165the SPI flash regions. In particular it provides the base address and
166size of the ME (Management Engine) region, allowing us to place the ME
167binary in the right place.
168
169With this entry in your image, the position of the 'intel-me' entry will be
170fixed in the image, which avoids you needed to specify an offset for that
171region. This is useful, because it is not possible to change the position
172of the ME region without updating the descriptor.
173
174See README.x86 for information about x86 binary blobs.
175
176
177
178Entry: intel-fsp: Entry containing an Intel Firmware Support Package (FSP) file
179-------------------------------------------------------------------------------
180
181Properties / Entry arguments:
182    - filename: Filename of file to read into entry
183
184This file contains binary blobs which are used on some devices to make the
185platform work. U-Boot executes this code since it is not possible to set up
186the hardware using U-Boot open-source code. Documentation is typically not
187available in sufficient detail to allow this.
188
189An example filename is 'FSP/QUEENSBAY_FSP_GOLD_001_20-DECEMBER-2013.fd'
190
191See README.x86 for information about x86 binary blobs.
192
193
194
195Entry: intel-me: Entry containing an Intel Management Engine (ME) file
196----------------------------------------------------------------------
197
198Properties / Entry arguments:
199    - filename: Filename of file to read into entry
200
201This file contains code used by the SoC that is required to make it work.
202The Management Engine is like a background task that runs things that are
203not clearly documented, but may include keyboard, deplay and network
204access. For platform that use ME it is not possible to disable it. U-Boot
205does not directly execute code in the ME binary.
206
207A typical filename is 'me.bin'.
208
209See README.x86 for information about x86 binary blobs.
210
211
212
213Entry: intel-mrc: Entry containing an Intel Memory Reference Code (MRC) file
214----------------------------------------------------------------------------
215
216Properties / Entry arguments:
217    - filename: Filename of file to read into entry
218
219This file contains code for setting up the SDRAM on some Intel systems. This
220is executed by U-Boot when needed early during startup. A typical filename
221is 'mrc.bin'.
222
223See README.x86 for information about x86 binary blobs.
224
225
226
227Entry: intel-vbt: Entry containing an Intel Video BIOS Table (VBT) file
228-----------------------------------------------------------------------
229
230Properties / Entry arguments:
231    - filename: Filename of file to read into entry
232
233This file contains code that sets up the integrated graphics subsystem on
234some Intel SoCs. U-Boot executes this when the display is started up.
235
236See README.x86 for information about Intel binary blobs.
237
238
239
240Entry: intel-vga: Entry containing an Intel Video Graphics Adaptor (VGA) file
241-----------------------------------------------------------------------------
242
243Properties / Entry arguments:
244    - filename: Filename of file to read into entry
245
246This file contains code that sets up the integrated graphics subsystem on
247some Intel SoCs. U-Boot executes this when the display is started up.
248
249This is similar to the VBT file but in a different format.
250
251See README.x86 for information about Intel binary blobs.
252
253
254
255Entry: section: Entry that contains other entries
256-------------------------------------------------
257
258Properties / Entry arguments: (see binman README for more information)
259    - size: Size of section in bytes
260    - align-size: Align size to a particular power of two
261    - pad-before: Add padding before the entry
262    - pad-after: Add padding after the entry
263    - pad-byte: Pad byte to use when padding
264    - sort-by-offset: Reorder the entries by offset
265    - end-at-4gb: Used to build an x86 ROM which ends at 4GB (2^32)
266    - name-prefix: Adds a prefix to the name of every entry in the section
267        when writing out the map
268
269A section is an entry which can contain other entries, thus allowing
270hierarchical images to be created. See 'Sections and hierarchical images'
271in the binman README for more information.
272
273
274
275Entry: text: An entry which contains text
276-----------------------------------------
277
278The text can be provided either in the node itself or by a command-line
279argument. There is a level of indirection to allow multiple text strings
280and sharing of text.
281
282Properties / Entry arguments:
283    text-label: The value of this string indicates the property / entry-arg
284        that contains the string to place in the entry
285    <xxx> (actual name is the value of text-label): contains the string to
286        place in the entry.
287
288Example node:
289
290    text {
291        size = <50>;
292        text-label = "message";
293    };
294
295You can then use:
296
297    binman -amessage="this is my message"
298
299and binman will insert that string into the entry.
300
301It is also possible to put the string directly in the node:
302
303    text {
304        size = <8>;
305        text-label = "message";
306        message = "a message directly in the node"
307    };
308
309The text is not itself nul-terminated. This can be achieved, if required,
310by setting the size of the entry to something larger than the text.
311
312
313
314Entry: u-boot: U-Boot flat binary
315---------------------------------
316
317Properties / Entry arguments:
318    - filename: Filename of u-boot.bin (default 'u-boot.bin')
319
320This is the U-Boot binary, containing relocation information to allow it
321to relocate itself at runtime. The binary typically includes a device tree
322blob at the end of it. Use u_boot_nodtb if you want to package the device
323tree separately.
324
325U-Boot can access binman symbols at runtime. See:
326
327    'Access to binman entry offsets at run time (fdt)'
328
329in the binman README for more information.
330
331
332
333Entry: u-boot-dtb: U-Boot device tree
334-------------------------------------
335
336Properties / Entry arguments:
337    - filename: Filename of u-boot.dtb (default 'u-boot.dtb')
338
339This is the U-Boot device tree, containing configuration information for
340U-Boot. U-Boot needs this to know what devices are present and which drivers
341to activate.
342
343Note: This is mostly an internal entry type, used by others. This allows
344binman to know which entries contain a device tree.
345
346
347
348Entry: u-boot-dtb-with-ucode: A U-Boot device tree file, with the microcode removed
349-----------------------------------------------------------------------------------
350
351Properties / Entry arguments:
352    - filename: Filename of u-boot.dtb (default 'u-boot.dtb')
353
354See Entry_u_boot_ucode for full details of the three entries involved in
355this process. This entry provides the U-Boot device-tree file, which
356contains the microcode. If the microcode is not being collated into one
357place then the offset and size of the microcode is recorded by this entry,
358for use by u_boot_with_ucode_ptr. If it is being collated, then this
359entry deletes the microcode from the device tree (to save space) and makes
360it available to u_boot_ucode.
361
362
363
364Entry: u-boot-img: U-Boot legacy image
365--------------------------------------
366
367Properties / Entry arguments:
368    - filename: Filename of u-boot.img (default 'u-boot.img')
369
370This is the U-Boot binary as a packaged image, in legacy format. It has a
371header which allows it to be loaded at the correct address for execution.
372
373You should use FIT (Flat Image Tree) instead of the legacy image for new
374applications.
375
376
377
378Entry: u-boot-nodtb: U-Boot flat binary without device tree appended
379--------------------------------------------------------------------
380
381Properties / Entry arguments:
382    - filename: Filename of u-boot.bin (default 'u-boot-nodtb.bin')
383
384This is the U-Boot binary, containing relocation information to allow it
385to relocate itself at runtime. It does not include a device tree blob at
386the end of it so normally cannot work without it. You can add a u_boot_dtb
387entry after this one, or use a u_boot entry instead (which contains both
388U-Boot and the device tree).
389
390
391
392Entry: u-boot-spl: U-Boot SPL binary
393------------------------------------
394
395Properties / Entry arguments:
396    - filename: Filename of u-boot-spl.bin (default 'spl/u-boot-spl.bin')
397
398This is the U-Boot SPL (Secondary Program Loader) binary. This is a small
399binary which loads before U-Boot proper, typically into on-chip SRAM. It is
400responsible for locating, loading and jumping to U-Boot. Note that SPL is
401not relocatable so must be loaded to the correct address in SRAM, or written
402to run from the correct address if direct flash execution is possible (e.g.
403on x86 devices).
404
405SPL can access binman symbols at runtime. See:
406
407    'Access to binman entry offsets at run time (symbols)'
408
409in the binman README for more information.
410
411The ELF file 'spl/u-boot-spl' must also be available for this to work, since
412binman uses that to look up symbols to write into the SPL binary.
413
414
415
416Entry: u-boot-spl-bss-pad: U-Boot SPL binary padded with a BSS region
417---------------------------------------------------------------------
418
419Properties / Entry arguments:
420    None
421
422This is similar to u_boot_spl except that padding is added after the SPL
423binary to cover the BSS (Block Started by Symbol) region. This region holds
424the various used by SPL. It is set to 0 by SPL when it starts up. If you
425want to append data to the SPL image (such as a device tree file), you must
426pad out the BSS region to avoid the data overlapping with U-Boot variables.
427This entry is useful in that case. It automatically pads out the entry size
428to cover both the code, data and BSS.
429
430The ELF file 'spl/u-boot-spl' must also be available for this to work, since
431binman uses that to look up the BSS address.
432
433
434
435Entry: u-boot-spl-dtb: U-Boot SPL device tree
436---------------------------------------------
437
438Properties / Entry arguments:
439    - filename: Filename of u-boot.dtb (default 'spl/u-boot-spl.dtb')
440
441This is the SPL device tree, containing configuration information for
442SPL. SPL needs this to know what devices are present and which drivers
443to activate.
444
445
446
447Entry: u-boot-spl-nodtb: SPL binary without device tree appended
448----------------------------------------------------------------
449
450Properties / Entry arguments:
451    - filename: Filename of spl/u-boot-spl-nodtb.bin (default
452        'spl/u-boot-spl-nodtb.bin')
453
454This is the U-Boot SPL binary, It does not include a device tree blob at
455the end of it so may not be able to work without it, assuming SPL needs
456a device tree to operation on your platform. You can add a u_boot_spl_dtb
457entry after this one, or use a u_boot_spl entry instead (which contains
458both SPL and the device tree).
459
460
461
462Entry: u-boot-spl-with-ucode-ptr: U-Boot SPL with embedded microcode pointer
463----------------------------------------------------------------------------
464
465See Entry_u_boot_ucode for full details of the entries involved in this
466process.
467
468
469
470Entry: u-boot-tpl: U-Boot TPL binary
471------------------------------------
472
473Properties / Entry arguments:
474    - filename: Filename of u-boot-tpl.bin (default 'tpl/u-boot-tpl.bin')
475
476This is the U-Boot TPL (Tertiary Program Loader) binary. This is a small
477binary which loads before SPL, typically into on-chip SRAM. It is
478responsible for locating, loading and jumping to SPL, the next-stage
479loader. Note that SPL is not relocatable so must be loaded to the correct
480address in SRAM, or written to run from the correct address if direct
481flash execution is possible (e.g. on x86 devices).
482
483SPL can access binman symbols at runtime. See:
484
485    'Access to binman entry offsets at run time (symbols)'
486
487in the binman README for more information.
488
489The ELF file 'tpl/u-boot-tpl' must also be available for this to work, since
490binman uses that to look up symbols to write into the TPL binary.
491
492
493
494Entry: u-boot-tpl-dtb: U-Boot TPL device tree
495---------------------------------------------
496
497Properties / Entry arguments:
498    - filename: Filename of u-boot.dtb (default 'tpl/u-boot-tpl.dtb')
499
500This is the TPL device tree, containing configuration information for
501TPL. TPL needs this to know what devices are present and which drivers
502to activate.
503
504
505
506Entry: u-boot-ucode: U-Boot microcode block
507-------------------------------------------
508
509Properties / Entry arguments:
510    None
511
512The contents of this entry are filled in automatically by other entries
513which must also be in the image.
514
515U-Boot on x86 needs a single block of microcode. This is collected from
516the various microcode update nodes in the device tree. It is also unable
517to read the microcode from the device tree on platforms that use FSP
518(Firmware Support Package) binaries, because the API requires that the
519microcode is supplied before there is any SRAM available to use (i.e.
520the FSP sets up the SRAM / cache-as-RAM but does so in the call that
521requires the microcode!). To keep things simple, all x86 platforms handle
522microcode the same way in U-Boot (even non-FSP platforms). This is that
523a table is placed at _dt_ucode_base_size containing the base address and
524size of the microcode. This is either passed to the FSP (for FSP
525platforms), or used to set up the microcode (for non-FSP platforms).
526This all happens in the build system since it is the only way to get
527the microcode into a single blob and accessible without SRAM.
528
529There are two cases to handle. If there is only one microcode blob in
530the device tree, then the ucode pointer it set to point to that. This
531entry (u-boot-ucode) is empty. If there is more than one update, then
532this entry holds the concatenation of all updates, and the device tree
533entry (u-boot-dtb-with-ucode) is updated to remove the microcode. This
534last step ensures that that the microcode appears in one contiguous
535block in the image and is not unnecessarily duplicated in the device
536tree. It is referred to as 'collation' here.
537
538Entry types that have a part to play in handling microcode:
539
540    Entry_u_boot_with_ucode_ptr:
541        Contains u-boot-nodtb.bin (i.e. U-Boot without the device tree).
542        It updates it with the address and size of the microcode so that
543        U-Boot can find it early on start-up.
544    Entry_u_boot_dtb_with_ucode:
545        Contains u-boot.dtb. It stores the microcode in a
546        'self.ucode_data' property, which is then read by this class to
547        obtain the microcode if needed. If collation is performed, it
548        removes the microcode from the device tree.
549    Entry_u_boot_ucode:
550        This class. If collation is enabled it reads the microcode from
551        the Entry_u_boot_dtb_with_ucode entry, and uses it as the
552        contents of this entry.
553
554
555
556Entry: u-boot-with-ucode-ptr: U-Boot with embedded microcode pointer
557--------------------------------------------------------------------
558
559Properties / Entry arguments:
560    - filename: Filename of u-boot-nodtb.dtb (default 'u-boot-nodtb.dtb')
561    - optional-ucode: boolean property to make microcode optional. If the
562        u-boot.bin image does not include microcode, no error will
563        be generated.
564
565See Entry_u_boot_ucode for full details of the three entries involved in
566this process. This entry updates U-Boot with the offset and size of the
567microcode, to allow early x86 boot code to find it without doing anything
568complicated. Otherwise it is the same as the u_boot entry.
569
570
571
572Entry: vblock: An entry which contains a Chromium OS verified boot block
573------------------------------------------------------------------------
574
575Properties / Entry arguments:
576    - keydir: Directory containing the public keys to use
577    - keyblock: Name of the key file to use (inside keydir)
578    - signprivate: Name of provide key file to use (inside keydir)
579    - version: Version number of the vblock (typically 1)
580    - kernelkey: Name of the kernel key to use (inside keydir)
581    - preamble-flags: Value of the vboot preamble flags (typically 0)
582
583Output files:
584    - input.<unique_name> - input file passed to futility
585    - vblock.<unique_name> - output file generated by futility (which is
586        used as the entry contents)
587
588Chromium OS signs the read-write firmware and kernel, writing the signature
589in this block. This allows U-Boot to verify that the next firmware stage
590and kernel are genuine.
591
592
593
594Entry: x86-start16: x86 16-bit start-up code for U-Boot
595-------------------------------------------------------
596
597Properties / Entry arguments:
598    - filename: Filename of u-boot-x86-16bit.bin (default
599        'u-boot-x86-16bit.bin')
600
601x86 CPUs start up in 16-bit mode, even if they are 32-bit CPUs. This code
602must be placed at a particular address. This entry holds that code. It is
603typically placed at offset CONFIG_SYS_X86_START16. The code is responsible
604for changing to 32-bit mode and jumping to U-Boot's entry point, which
605requires 32-bit mode (for 32-bit U-Boot).
606
607For 64-bit U-Boot, the 'x86_start16_spl' entry type is used instead.
608
609
610
611Entry: x86-start16-spl: x86 16-bit start-up code for SPL
612--------------------------------------------------------
613
614Properties / Entry arguments:
615    - filename: Filename of spl/u-boot-x86-16bit-spl.bin (default
616        'spl/u-boot-x86-16bit-spl.bin')
617
618x86 CPUs start up in 16-bit mode, even if they are 64-bit CPUs. This code
619must be placed at a particular address. This entry holds that code. It is
620typically placed at offset CONFIG_SYS_X86_START16. The code is responsible
621for changing to 32-bit mode and starting SPL, which in turn changes to
62264-bit mode and jumps to U-Boot (for 64-bit U-Boot).
623
624For 32-bit U-Boot, the 'x86_start16' entry type is used instead.
625
626
627
628Entry: x86-start16-tpl: x86 16-bit start-up code for TPL
629--------------------------------------------------------
630
631Properties / Entry arguments:
632    - filename: Filename of tpl/u-boot-x86-16bit-tpl.bin (default
633        'tpl/u-boot-x86-16bit-tpl.bin')
634
635x86 CPUs start up in 16-bit mode, even if they are 64-bit CPUs. This code
636must be placed at a particular address. This entry holds that code. It is
637typically placed at offset CONFIG_SYS_X86_START16. The code is responsible
638for changing to 32-bit mode and starting TPL, which in turn jumps to SPL.
639
640If TPL is not being used, the 'x86_start16_spl or 'x86_start16' entry types
641may be used instead.
642
643
644
645