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Anton Staaf 033089f290 dtc: Add support for variable sized elements
Elements of size 8, 16, 32, and 64 bits are supported.  The new
/bits/ syntax was selected so as to not pollute the reserved
keyword space with uint8/uint16/... type names.

With this patch the following property assignment:

    property = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;

is equivalent to:

    property = <0x12345678 0x0000ffff>;

It is now also possible to directly specify a 64 bit literal in a
cell list, also known as an array using:

    property = /bits/ 64 <0xdeadbeef00000000>;

It is an error to attempt to store a literal into an element that is
too small to hold the literal, and the compiler will generate an
error when it detects this.  For instance:

    property = /bits/ 8 <256>;

Will fail to compile.  It is also an error to attempt to place a
reference in a non 32-bit element.

The documentation has been changed to reflect that the cell list
is now an array of elements that can be of sizes other than the
default 32-bit cell size.

The sized_cells test tests the creation and access of 8, 16, 32,
and 64-bit sized elements.  It also tests that the creation of two
properties, one with 16 bit elements and one with 32 bit elements
result in the same property contents.

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
2011-10-11 12:58:30 -05:00
Documentation dtc: Add support for variable sized elements 2011-10-11 12:58:30 -05:00
libfdt libfdt: Add fdt16_to_cpu utility function 2011-10-11 12:57:36 -05:00
scripts Add DTC release version information. 2007-07-07 13:52:25 -05:00
tests dtc: Add support for variable sized elements 2011-10-11 12:58:30 -05:00
.gitignore Update .gitignore files 2010-02-25 11:47:58 -06:00
checks.c dtc: Allow multiple labels on nodes and properties 2010-02-24 08:48:51 -06:00
convert-dtsv0-lexer.l dtc: Add -Wredundant-decls (resend) 2010-04-30 08:36:47 -05:00
data.c dtc: Add data_append_integer function 2011-10-11 12:58:03 -05:00
dtc-lexer.l dtc: Add support for variable sized elements 2011-10-11 12:58:30 -05:00
dtc-parser.y dtc: Add support for variable sized elements 2011-10-11 12:58:30 -05:00
dtc.c dtc: Remove unused check variable 2011-07-17 07:31:11 -05:00
dtc.h dtc: Add data_append_integer function 2011-10-11 12:58:03 -05:00
dtdiff dtc: Add code to make diffing trees easier 2010-11-13 15:47:29 -06:00
flattree.c dtc: Remove unused variable in flat_read_mem_reserve 2011-07-17 07:32:59 -05:00
fstree.c Fix a filehandle leak 2010-07-14 17:29:19 -05:00
ftdump.c ftdump: use utilfdt to read blob 2011-09-22 13:50:50 -05:00
GPL dtc: Remove redundant copy of the GPL 2007-06-25 21:43:11 -05:00
livetree.c dtc: Add code to make diffing trees easier 2010-11-13 15:47:29 -06:00
Makefile Add fdt read/write utility functions 2011-09-22 13:49:33 -05:00
Makefile.convert-dtsv0 Implement and use an xstrdup() function 2008-10-03 11:12:33 -05:00
Makefile.dtc Implement and use an xstrdup() function 2008-10-03 11:12:33 -05:00
Makefile.utils Create Makefile.utils and move ftdump into it 2011-09-22 10:16:28 -05:00
README.license dtc/libfdt: Add README clarifying licensing 2008-01-04 08:37:36 -06:00
srcpos.c Create new and use new print_error that uses printf style formatting. 2010-10-20 22:36:53 -06:00
srcpos.h Create new and use new print_error that uses printf style formatting. 2010-10-20 22:36:53 -06:00
TODO dtc: Update TODO files 2007-12-19 08:20:26 -06:00
treesource.c dtc: Allow multiple labels on nodes and properties 2010-02-24 08:48:51 -06:00
util.c Add fdt read/write utility functions 2011-09-22 13:49:33 -05:00
util.h Add fdt read/write utility functions 2011-09-22 13:49:33 -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