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Oleksandr Tymoshenko 26f47fdd8f Add FDT overlays support to ubldr
FDT overlays is de-facto standard for describing expansion boards like
Beaglebone capes or Raspberry Pi shields. The ides is to have basic
DTB for base board and overlays DTB for shields/capes and to construct
final DTB either using human-readable configuration or some
self-discovery mechanism. I believe this approach can also be expanded
to support dynamically loadable FPGA bitstreams on systems like
Zedboard/Zybo.

Overlaying process is simmilar to executable link process for
binaries: each DTB has "exported" symbols and "undefined" symbols, the
latter are resolved using information for the former obtained from
base DTB or one of the overlays applied earlier (more rare case).

This symbols information is not generated by standard dtc that FreeBSD
has in base system, patched[1] version required to produces
overlay-compatible blobs. So although DTB files generated by
buildkernel do not support overlays there are enough
vendor/community-provided DTB blobs ciruclating around to justify
committing this change to ubldr.

This commit introduces handler for "fdt_overlays" variable that can be
defined either as a loader env variable or U-Boot env variable.
fdt_overlays is comma-separated list of .dtbo files located in
/boot/dtb/ directory along with base .dtb. ubldr loads files and
applies them one-by-one to base .dtb and then passes result blob to
the kernel.

[1] dd6a0533e8

Differential Revision:	https://reviews.freebsd.org/D3180
2016-04-29 22:42:59 +00:00
bin Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
cddl Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
contrib Stop using sbrk(2) with malloc. This helps reduce the number of places 2016-04-28 12:24:58 +00:00
crypto Re-add AES-CBC ciphers to the default cipher list on the server. 2016-03-11 00:23:10 +00:00
etc Add a savecore_enable variable support for the savecore rc script 2016-04-29 12:23:56 +00:00
gnu Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
include Vendor import of ntp-4.2.8p7. 2016-04-27 05:37:54 +00:00
kerberos5 Remove the old depend (mkdep) code and make FAST_DEPEND the one true way. 2016-03-30 23:50:23 +00:00
lib Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
libexec Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
release Replace the A20 kernel config with a generic ALLWINNER kernel config that 2016-04-21 16:49:04 +00:00
rescue Split /rescue into its own package. 2016-02-08 14:27:45 +00:00
sbin Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
secure Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
share Add a savecore_enable variable support for the savecore rc script 2016-04-29 12:23:56 +00:00
sys Add FDT overlays support to ubldr 2016-04-29 22:42:59 +00:00
targets Simplify building libpam and fix libpam.a not containing the modules since r284345. 2016-04-14 01:17:03 +00:00
tests Automate the subr_unit test. 2016-04-29 21:11:31 +00:00
tools Remove leftover from Big5HKSCS removal 2016-04-17 12:12:25 +00:00
usr.bin Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
usr.sbin Fix including Kyuafile in packaged base system. 2016-04-29 05:28:40 +00:00
.arcconfig Remove project.name which is a product of a bygone era. 2016-04-21 04:33:07 +00:00
.arclint phabricator related changes: 2015-04-20 20:33:22 +00:00
COPYRIGHT Bump copyright year. 2015-12-31 11:21:45 +00:00
LOCKS Explicitly require Security Officer's approval for kernel PRNG bits. 2013-09-17 14:19:05 +00:00
MAINTAINERS Add myself to MAINTAINERS. 2016-03-14 16:27:43 +00:00
Makefile Follow-up r298220: Don't pass down META_MODE which will still enable it. 2016-04-18 18:39:43 +00:00
Makefile.inc1 WITH_META_MODE: Allow buildkernel to create .meta files with curdir==objdir. 2016-04-26 18:08:51 +00:00
Makefile.libcompat Set CPP from XCPP for the libcompat build. 2016-04-15 18:32:05 +00:00
ObsoleteFiles.inc Remove mroute6d rc script 2016-04-23 13:24:45 +00:00
README Vendor import of file 4.26. 2016-04-18 04:43:03 +00:00
UPDATING Add update. 2016-04-15 04:45:37 +00:00

This is the top level of the FreeBSD source directory.  This file
was last revised on:
$FreeBSD$

For copyright information, please see the file COPYRIGHT in this
directory (additional copyright information also exists for some
sources in this tree - please see the specific source directories for
more information).

The Makefile in this directory supports a number of targets for
building components (or all) of the FreeBSD source tree.  See build(7)
and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html
for more information, including setting make(1) variables.

The `buildkernel` and `installkernel` targets build and install
the kernel and the modules (see below).  Please see the top of
the Makefile in this directory for more information on the
standard build targets and compile-time flags.

Building a kernel is a somewhat more involved process.  See build(7), config(8),
and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
for more information.

Note: If you want to build and install the kernel with the
`buildkernel` and `installkernel` targets, you might need to build
world before.  More information is available in the handbook.

The kernel configuration files reside in the sys/<arch>/conf
sub-directory.  GENERIC is the default configuration used in release builds.
NOTES contains entries and documentation for all possible
devices, not just those commonly used.


Source Roadmap:
---------------

bin		System/user commands.

cddl		Various commands and libraries under the Common Development
		and Distribution License.

contrib		Packages contributed by 3rd parties.

crypto		Cryptography stuff (see crypto/README).

etc		Template files for /etc.

games		Amusements.

gnu		Various commands and libraries under the GNU Public License.
		Please see gnu/COPYING* for more information.

include		System include files.

kerberos5	Kerberos5 (Heimdal) package.

lib		System libraries.

libexec		System daemons.

release		Release building Makefile & associated tools.

rescue		Build system for statically linked /rescue utilities.

sbin		System commands.

secure		Cryptographic libraries and commands.

share		Shared resources.

sys		Kernel sources.

tests		Regression tests which can be run by Kyua.  See tests/README
		for additional information.

tools		Utilities for regression testing and miscellaneous tasks.

usr.bin		User commands.

usr.sbin	System administration commands.


For information on synchronizing your source tree with one or more of
the FreeBSD Project's development branches, please see:

  http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html