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David Gibson 548767f42e dtc: Rework handling of boot_cpuid_phys
Currently, dtc will put the nonsense value 0xfeedbeef into the
boot_cpuid_phys field of an output blob, unless explicitly given
another value with the -b command line option.  As well as being a
totally unuseful default value, this also means that dtc won't
properly preserve the boot_cpuid_phys field in -I dtb -O dtb mode.

This patch reworks things to improve the boot_cpuid handling.  The new
semantics are that the output's boot_cpuid_phys value is:
	the value given on the command line if -b is used
otherwise
	the value from the input, if in -I dtb mode
otherwise
	0

Implementation-wise we do the following:
	- boot_cpuid_phys is added to struct boot_info, so that
structure now contains all of the blob's semantic information.
	- dt_to_blob() and dt_to_asm() output the cpuid given in
boot_info
	- dt_from_blob() fills in boot_info based on the input blob
	- The other dt_from_*() functions just record 0, but we can
change this easily if e.g. we invent a way of specifying the boot cpu
in the source format.
	- main() overrides the cpuid in the boot_info between input
and output if -b is given

We add some testcases to check this new behaviour.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2008-05-19 14:12:15 -05:00
Documentation dtc: Add some documentation for the dts formta 2008-03-23 08:00:33 -05:00
libfdt dtc: Clean up included Makefile fragments 2008-05-19 14:07:53 -05:00
scripts Add DTC release version information. 2007-07-07 13:52:25 -05:00
tests dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
.gitignore Merge libfdt into dtc. 2007-06-14 15:05:55 +10:00
checks.c dtc: Strip redundant "name" properties 2008-03-23 08:00:33 -05:00
data.c dtc: Cleanup \nnn and \xNN string escape handling 2008-03-23 08:00:33 -05:00
dtc-lexer.l dtc: Remove ugly include stack abuse 2008-03-23 08:00:33 -05:00
dtc-parser.y dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
dtc.c dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
dtc.h dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
flattree.c dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
fstree.c dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
ftdump.c dtc: Remove header information dumping 2008-01-03 07:46:29 -06:00
GPL dtc: Remove redundant copy of the GPL 2007-06-25 21:43:11 -05:00
livetree.c dtc: Rework handling of boot_cpuid_phys 2008-05-19 14:12:15 -05:00
Makefile dtc: Clean up included Makefile fragments 2008-05-19 14:07:53 -05:00
Makefile.dtc dtc: Clean up included Makefile fragments 2008-05-19 14:07:53 -05:00
README.license dtc/libfdt: Add README clarifying licensing 2008-01-04 08:37:36 -06:00
srcpos.c dtc: Make dtc_open_file() die() if unable to open requested file 2008-03-23 08:00:33 -05:00
srcpos.h dtc: Remove ugly include stack abuse 2008-03-23 08:00:33 -05:00
TODO dtc: Update TODO files 2007-12-19 08:20:26 -06:00
treesource.c dtc: Simplify error handling for unparseable input 2008-05-19 14:07:40 -05:00

Licensing and contribution policy of dtc and libfdt
===================================================

This dtc package contains two pieces of software: dtc itself, and
libfdt which comprises the files in the libfdt/ subdirectory.  These
two pieces of software, although closely related, are quite distinct.
dtc does not incoporate or rely on libfdt for its operation, nor vice
versa.  It is important that these two pieces of software have
different license conditions.

As the copyright banners in each source file attest, dtc is licensed
under the GNU GPL.  The full text of the GPL can be found in the file
entitled 'GPL' which should be included in this package.  dtc code,
therefore, may not be incorporated into works which do not have a GPL
compatible license.

libfdt, however, is GPL/BSD dual-licensed.  That is, it may be used
either under the terms of the GPL, or under the terms of the 2-clause
BSD license (aka the ISC license).  The full terms of that license are
given in the copyright banners of each of the libfdt source files.
This is, in practice, equivalent to being BSD licensed, since the
terms of the BSD license are strictly more permissive than the GPL.

I made the decision to license libfdt in this way because I want to
encourage widespread and correct usage of flattened device trees,
including by proprietary or otherwise GPL-incompatible firmware or
tools.  Allowing libfdt to be used under the terms of the BSD license
makes that it easier for vendors or authors of such software to do so.

This does mean that libfdt code could be "stolen" - say, included in a
proprietary fimware and extended without contributing those extensions
back to the libfdt mainline.  While I hope that doesn't happen, I
believe the goal of allowing libfdt to be widely used is more
important than avoiding that.  libfdt is quite small, and hardly
rocket science; so the incentive for such impolite behaviour is small,
and the inconvenience caused therby is not dire.

Licenses such as the LGPL which would allow code to be used in non-GPL
software, but also require contributions to be returned were
considered.  However, libfdt is designed to be used in firmwares and
other environments with unusual technical constraints.  It's difficult
to anticipate all possible changes which might be needed to meld
libfdt into such environments and so difficult to suitably word a
license that puts the boundary between what is and isn't permitted in
the intended place.  Again, I judged encouraging widespread use of
libfdt by keeping the license terms simple and familiar to be the more
important goal.

**IMPORTANT** It's intended that all of libfdt as released remain
permissively licensed this way.  Therefore only contributions which
are released under these terms can be merged into the libfdt mainline.


David Gibson <david@gibson.dropbear.id.au>
(principal original author of dtc and libfdt)
2 November 2007