xref: /openbmc/u-boot/tools/binman/README.entries (revision 73e4ba98)
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
23This entry reads data from a file and places it in the entry. The
24default filename is often specified specified by the subclass. See for
25example the 'u_boot' entry which provides the filename 'u-boot.bin'.
26
27
28
29Entry: blob-named-by-arg: A blob entry which gets its filename property from its subclass
30-----------------------------------------------------------------------------------------
31
32Properties / Entry arguments:
33    - <xxx>-path: Filename containing the contents of this entry (optional,
34        defaults to 0)
35
36where <xxx> is the blob_fname argument to the constructor.
37
38This entry cannot be used directly. Instead, it is used as a parent class
39for another entry, which defined blob_fname. This parameter is used to
40set the entry-arg or property containing the filename. The entry-arg or
41property is in turn used to set the actual filename.
42
43See cros_ec_rw for an example of this.
44
45
46
47Entry: cros-ec-rw: A blob entry which contains a Chromium OS read-write EC image
48--------------------------------------------------------------------------------
49
50Properties / Entry arguments:
51    - cros-ec-rw-path: Filename containing the EC image
52
53This entry holds a Chromium OS EC (embedded controller) image, for use in
54updating the EC on startup via software sync.
55
56
57
58Entry: fill: An entry which is filled to a particular byte value
59----------------------------------------------------------------
60
61Properties / Entry arguments:
62    - fill-byte: Byte to use to fill the entry
63
64Note that the size property must be set since otherwise this entry does not
65know how large it should be.
66
67You can often achieve the same effect using the pad-byte property of the
68overall image, in that the space between entries will then be padded with
69that byte. But this entry is sometimes useful for explicitly setting the
70byte value of a region.
71
72
73
74Entry: fmap: An entry which contains an Fmap section
75----------------------------------------------------
76
77Properties / Entry arguments:
78    None
79
80FMAP is a simple format used by flashrom, an open-source utility for
81reading and writing the SPI flash, typically on x86 CPUs. The format
82provides flashrom with a list of areas, so it knows what it in the flash.
83It can then read or write just a single area, instead of the whole flash.
84
85The format is defined by the flashrom project, in the file lib/fmap.h -
86see www.flashrom.org/Flashrom for more information.
87
88When used, this entry will be populated with an FMAP which reflects the
89entries in the current image. Note that any hierarchy is squashed, since
90FMAP does not support this.
91
92
93
94Entry: gbb: An entry which contains a Chromium OS Google Binary Block
95---------------------------------------------------------------------
96
97Properties / Entry arguments:
98    - hardware-id: Hardware ID to use for this build (a string)
99    - keydir: Directory containing the public keys to use
100    - bmpblk: Filename containing images used by recovery
101
102Chromium OS uses a GBB to store various pieces of information, in particular
103the root and recovery keys that are used to verify the boot process. Some
104more details are here:
105
106    https://www.chromium.org/chromium-os/firmware-porting-guide/2-concepts
107
108but note that the page dates from 2013 so is quite out of date. See
109README.chromium for how to obtain the required keys and tools.
110
111
112
113Entry: intel-cmc: Entry containing an Intel Chipset Micro Code (CMC) file
114-------------------------------------------------------------------------
115
116Properties / Entry arguments:
117    - filename: Filename of file to read into entry
118
119This file contains microcode for some devices in a special format. An
120example filename is 'Microcode/C0_22211.BIN'.
121
122See README.x86 for information about x86 binary blobs.
123
124
125
126Entry: intel-descriptor: Intel flash descriptor block (4KB)
127-----------------------------------------------------------
128
129Properties / Entry arguments:
130    filename: Filename of file containing the descriptor. This is typically
131        a 4KB binary file, sometimes called 'descriptor.bin'
132
133This entry is placed at the start of flash and provides information about
134the SPI flash regions. In particular it provides the base address and
135size of the ME (Management Engine) region, allowing us to place the ME
136binary in the right place.
137
138With this entry in your image, the position of the 'intel-me' entry will be
139fixed in the image, which avoids you needed to specify an offset for that
140region. This is useful, because it is not possible to change the position
141of the ME region without updating the descriptor.
142
143See README.x86 for information about x86 binary blobs.
144
145
146
147Entry: intel-fsp: Entry containing an Intel Firmware Support Package (FSP) file
148-------------------------------------------------------------------------------
149
150Properties / Entry arguments:
151    - filename: Filename of file to read into entry
152
153This file contains binary blobs which are used on some devices to make the
154platform work. U-Boot executes this code since it is not possible to set up
155the hardware using U-Boot open-source code. Documentation is typically not
156available in sufficient detail to allow this.
157
158An example filename is 'FSP/QUEENSBAY_FSP_GOLD_001_20-DECEMBER-2013.fd'
159
160See README.x86 for information about x86 binary blobs.
161
162
163
164Entry: intel-me: Entry containing an Intel Management Engine (ME) file
165----------------------------------------------------------------------
166
167Properties / Entry arguments:
168    - filename: Filename of file to read into entry
169
170This file contains code used by the SoC that is required to make it work.
171The Management Engine is like a background task that runs things that are
172not clearly documented, but may include keyboard, deplay and network
173access. For platform that use ME it is not possible to disable it. U-Boot
174does not directly execute code in the ME binary.
175
176A typical filename is 'me.bin'.
177
178See README.x86 for information about x86 binary blobs.
179
180
181
182Entry: intel-mrc: Entry containing an Intel Memory Reference Code (MRC) file
183----------------------------------------------------------------------------
184
185Properties / Entry arguments:
186    - filename: Filename of file to read into entry
187
188This file contains code for setting up the SDRAM on some Intel systems. This
189is executed by U-Boot when needed early during startup. A typical filename
190is 'mrc.bin'.
191
192See README.x86 for information about x86 binary blobs.
193
194
195
196Entry: intel-vbt: Entry containing an Intel Video BIOS Table (VBT) file
197-----------------------------------------------------------------------
198
199Properties / Entry arguments:
200    - filename: Filename of file to read into entry
201
202This file contains code that sets up the integrated graphics subsystem on
203some Intel SoCs. U-Boot executes this when the display is started up.
204
205See README.x86 for information about Intel binary blobs.
206
207
208
209Entry: intel-vga: Entry containing an Intel Video Graphics Adaptor (VGA) file
210-----------------------------------------------------------------------------
211
212Properties / Entry arguments:
213    - filename: Filename of file to read into entry
214
215This file contains code that sets up the integrated graphics subsystem on
216some Intel SoCs. U-Boot executes this when the display is started up.
217
218This is similar to the VBT file but in a different format.
219
220See README.x86 for information about Intel binary blobs.
221
222
223
224Entry: section: Entry that contains other entries
225-------------------------------------------------
226
227Properties / Entry arguments: (see binman README for more information)
228    - size: Size of section in bytes
229    - align-size: Align size to a particular power of two
230    - pad-before: Add padding before the entry
231    - pad-after: Add padding after the entry
232    - pad-byte: Pad byte to use when padding
233    - sort-by-offset: Reorder the entries by offset
234    - end-at-4gb: Used to build an x86 ROM which ends at 4GB (2^32)
235    - name-prefix: Adds a prefix to the name of every entry in the section
236        when writing out the map
237
238A section is an entry which can contain other entries, thus allowing
239hierarchical images to be created. See 'Sections and hierarchical images'
240in the binman README for more information.
241
242
243
244Entry: text: An entry which contains text
245-----------------------------------------
246
247The text can be provided either in the node itself or by a command-line
248argument. There is a level of indirection to allow multiple text strings
249and sharing of text.
250
251Properties / Entry arguments:
252    text-label: The value of this string indicates the property / entry-arg
253        that contains the string to place in the entry
254    <xxx> (actual name is the value of text-label): contains the string to
255        place in the entry.
256
257Example node:
258
259    text {
260        size = <50>;
261        text-label = "message";
262    };
263
264You can then use:
265
266    binman -amessage="this is my message"
267
268and binman will insert that string into the entry.
269
270It is also possible to put the string directly in the node:
271
272    text {
273        size = <8>;
274        text-label = "message";
275        message = "a message directly in the node"
276    };
277
278The text is not itself nul-terminated. This can be achieved, if required,
279by setting the size of the entry to something larger than the text.
280
281
282
283Entry: u-boot: U-Boot flat binary
284---------------------------------
285
286Properties / Entry arguments:
287    - filename: Filename of u-boot.bin (default 'u-boot.bin')
288
289This is the U-Boot binary, containing relocation information to allow it
290to relocate itself at runtime. The binary typically includes a device tree
291blob at the end of it. Use u_boot_nodtb if you want to package the device
292tree separately.
293
294U-Boot can access binman symbols at runtime. See:
295
296    'Access to binman entry offsets at run time (fdt)'
297
298in the binman README for more information.
299
300
301
302Entry: u-boot-dtb: U-Boot device tree
303-------------------------------------
304
305Properties / Entry arguments:
306    - filename: Filename of u-boot.dtb (default 'u-boot.dtb')
307
308This is the U-Boot device tree, containing configuration information for
309U-Boot. U-Boot needs this to know what devices are present and which drivers
310to activate.
311
312
313
314Entry: u-boot-dtb-with-ucode: A U-Boot device tree file, with the microcode removed
315-----------------------------------------------------------------------------------
316
317Properties / Entry arguments:
318    - filename: Filename of u-boot.dtb (default 'u-boot.dtb')
319
320See Entry_u_boot_ucode for full details of the three entries involved in
321this process. This entry provides the U-Boot device-tree file, which
322contains the microcode. If the microcode is not being collated into one
323place then the offset and size of the microcode is recorded by this entry,
324for use by u_boot_with_ucode_ptr. If it is being collated, then this
325entry deletes the microcode from the device tree (to save space) and makes
326it available to u_boot_ucode.
327
328
329
330Entry: u-boot-img: U-Boot legacy image
331--------------------------------------
332
333Properties / Entry arguments:
334    - filename: Filename of u-boot.img (default 'u-boot.img')
335
336This is the U-Boot binary as a packaged image, in legacy format. It has a
337header which allows it to be loaded at the correct address for execution.
338
339You should use FIT (Flat Image Tree) instead of the legacy image for new
340applications.
341
342
343
344Entry: u-boot-nodtb: U-Boot flat binary without device tree appended
345--------------------------------------------------------------------
346
347Properties / Entry arguments:
348    - filename: Filename of u-boot.bin (default 'u-boot-nodtb.bin')
349
350This is the U-Boot binary, containing relocation information to allow it
351to relocate itself at runtime. It does not include a device tree blob at
352the end of it so normally cannot work without it. You can add a u_boot_dtb
353entry after this one, or use a u_boot entry instead (which contains both
354U-Boot and the device tree).
355
356
357
358Entry: u-boot-spl: U-Boot SPL binary
359------------------------------------
360
361Properties / Entry arguments:
362    - filename: Filename of u-boot-spl.bin (default 'spl/u-boot-spl.bin')
363
364This is the U-Boot SPL (Secondary Program Loader) binary. This is a small
365binary which loads before U-Boot proper, typically into on-chip SRAM. It is
366responsible for locating, loading and jumping to U-Boot. Note that SPL is
367not relocatable so must be loaded to the correct address in SRAM, or written
368to run from the correct address if direct flash execution is possible (e.g.
369on x86 devices).
370
371SPL can access binman symbols at runtime. See:
372
373    'Access to binman entry offsets at run time (symbols)'
374
375in the binman README for more information.
376
377The ELF file 'spl/u-boot-spl' must also be available for this to work, since
378binman uses that to look up symbols to write into the SPL binary.
379
380
381
382Entry: u-boot-spl-bss-pad: U-Boot SPL binary padded with a BSS region
383---------------------------------------------------------------------
384
385Properties / Entry arguments:
386    None
387
388This is similar to u_boot_spl except that padding is added after the SPL
389binary to cover the BSS (Block Started by Symbol) region. This region holds
390the various used by SPL. It is set to 0 by SPL when it starts up. If you
391want to append data to the SPL image (such as a device tree file), you must
392pad out the BSS region to avoid the data overlapping with U-Boot variables.
393This entry is useful in that case. It automatically pads out the entry size
394to cover both the code, data and BSS.
395
396The ELF file 'spl/u-boot-spl' must also be available for this to work, since
397binman uses that to look up the BSS address.
398
399
400
401Entry: u-boot-spl-dtb: U-Boot SPL device tree
402---------------------------------------------
403
404Properties / Entry arguments:
405    - filename: Filename of u-boot.dtb (default 'spl/u-boot-spl.dtb')
406
407This is the SPL device tree, containing configuration information for
408SPL. SPL needs this to know what devices are present and which drivers
409to activate.
410
411
412
413Entry: u-boot-spl-nodtb: SPL binary without device tree appended
414----------------------------------------------------------------
415
416Properties / Entry arguments:
417    - filename: Filename of spl/u-boot-spl-nodtb.bin (default
418        'spl/u-boot-spl-nodtb.bin')
419
420This is the U-Boot SPL binary, It does not include a device tree blob at
421the end of it so may not be able to work without it, assuming SPL needs
422a device tree to operation on your platform. You can add a u_boot_spl_dtb
423entry after this one, or use a u_boot_spl entry instead (which contains
424both SPL and the device tree).
425
426
427
428Entry: u-boot-spl-with-ucode-ptr: U-Boot SPL with embedded microcode pointer
429----------------------------------------------------------------------------
430
431See Entry_u_boot_ucode for full details of the entries involved in this
432process.
433
434
435
436Entry: u-boot-tpl: U-Boot TPL binary
437------------------------------------
438
439Properties / Entry arguments:
440    - filename: Filename of u-boot-tpl.bin (default 'tpl/u-boot-tpl.bin')
441
442This is the U-Boot TPL (Tertiary Program Loader) binary. This is a small
443binary which loads before SPL, typically into on-chip SRAM. It is
444responsible for locating, loading and jumping to SPL, the next-stage
445loader. Note that SPL is not relocatable so must be loaded to the correct
446address in SRAM, or written to run from the correct address if direct
447flash execution is possible (e.g. on x86 devices).
448
449SPL can access binman symbols at runtime. See:
450
451    'Access to binman entry offsets at run time (symbols)'
452
453in the binman README for more information.
454
455The ELF file 'tpl/u-boot-tpl' must also be available for this to work, since
456binman uses that to look up symbols to write into the TPL binary.
457
458
459
460Entry: u-boot-tpl-dtb: U-Boot TPL device tree
461---------------------------------------------
462
463Properties / Entry arguments:
464    - filename: Filename of u-boot.dtb (default 'tpl/u-boot-tpl.dtb')
465
466This is the TPL device tree, containing configuration information for
467TPL. TPL needs this to know what devices are present and which drivers
468to activate.
469
470
471
472Entry: u-boot-ucode: U-Boot microcode block
473-------------------------------------------
474
475Properties / Entry arguments:
476    None
477
478The contents of this entry are filled in automatically by other entries
479which must also be in the image.
480
481U-Boot on x86 needs a single block of microcode. This is collected from
482the various microcode update nodes in the device tree. It is also unable
483to read the microcode from the device tree on platforms that use FSP
484(Firmware Support Package) binaries, because the API requires that the
485microcode is supplied before there is any SRAM available to use (i.e.
486the FSP sets up the SRAM / cache-as-RAM but does so in the call that
487requires the microcode!). To keep things simple, all x86 platforms handle
488microcode the same way in U-Boot (even non-FSP platforms). This is that
489a table is placed at _dt_ucode_base_size containing the base address and
490size of the microcode. This is either passed to the FSP (for FSP
491platforms), or used to set up the microcode (for non-FSP platforms).
492This all happens in the build system since it is the only way to get
493the microcode into a single blob and accessible without SRAM.
494
495There are two cases to handle. If there is only one microcode blob in
496the device tree, then the ucode pointer it set to point to that. This
497entry (u-boot-ucode) is empty. If there is more than one update, then
498this entry holds the concatenation of all updates, and the device tree
499entry (u-boot-dtb-with-ucode) is updated to remove the microcode. This
500last step ensures that that the microcode appears in one contiguous
501block in the image and is not unnecessarily duplicated in the device
502tree. It is referred to as 'collation' here.
503
504Entry types that have a part to play in handling microcode:
505
506    Entry_u_boot_with_ucode_ptr:
507        Contains u-boot-nodtb.bin (i.e. U-Boot without the device tree).
508        It updates it with the address and size of the microcode so that
509        U-Boot can find it early on start-up.
510    Entry_u_boot_dtb_with_ucode:
511        Contains u-boot.dtb. It stores the microcode in a
512        'self.ucode_data' property, which is then read by this class to
513        obtain the microcode if needed. If collation is performed, it
514        removes the microcode from the device tree.
515    Entry_u_boot_ucode:
516        This class. If collation is enabled it reads the microcode from
517        the Entry_u_boot_dtb_with_ucode entry, and uses it as the
518        contents of this entry.
519
520
521
522Entry: u-boot-with-ucode-ptr: U-Boot with embedded microcode pointer
523--------------------------------------------------------------------
524
525Properties / Entry arguments:
526    - filename: Filename of u-boot-nodtb.dtb (default 'u-boot-nodtb.dtb')
527
528See Entry_u_boot_ucode for full details of the three entries involved in
529this process. This entry updates U-Boot with the offset and size of the
530microcode, to allow early x86 boot code to find it without doing anything
531complicated. Otherwise it is the same as the u_boot entry.
532
533
534
535Entry: vblock: An entry which contains a Chromium OS verified boot block
536------------------------------------------------------------------------
537
538Properties / Entry arguments:
539    - keydir: Directory containing the public keys to use
540    - keyblock: Name of the key file to use (inside keydir)
541    - signprivate: Name of provide key file to use (inside keydir)
542    - version: Version number of the vblock (typically 1)
543    - kernelkey: Name of the kernel key to use (inside keydir)
544    - preamble-flags: Value of the vboot preamble flags (typically 0)
545
546Chromium OS  signs the read-write firmware and kernel, writing the signature
547in this block. This allows U-Boot to verify that the next firmware stage
548and kernel are genuine.
549
550
551
552Entry: x86-start16: x86 16-bit start-up code for U-Boot
553-------------------------------------------------------
554
555Properties / Entry arguments:
556    - filename: Filename of u-boot-x86-16bit.bin (default
557        'u-boot-x86-16bit.bin')
558
559x86 CPUs start up in 16-bit mode, even if they are 32-bit CPUs. This code
560must be placed at a particular address. This entry holds that code. It is
561typically placed at offset CONFIG_SYS_X86_START16. The code is responsible
562for changing to 32-bit mode and jumping to U-Boot's entry point, which
563requires 32-bit mode (for 32-bit U-Boot).
564
565For 64-bit U-Boot, the 'x86_start16_spl' entry type is used instead.
566
567
568
569Entry: x86-start16-spl: x86 16-bit start-up code for SPL
570--------------------------------------------------------
571
572Properties / Entry arguments:
573    - filename: Filename of spl/u-boot-x86-16bit-spl.bin (default
574        'spl/u-boot-x86-16bit-spl.bin')
575
576x86 CPUs start up in 16-bit mode, even if they are 64-bit CPUs. This code
577must be placed at a particular address. This entry holds that code. It is
578typically placed at offset CONFIG_SYS_X86_START16. The code is responsible
579for changing to 32-bit mode and starting SPL, which in turn changes to
58064-bit mode and jumps to U-Boot (for 64-bit U-Boot).
581
582For 32-bit U-Boot, the 'x86_start16' entry type is used instead.
583
584
585
586