Hi, I recently received a hint that it would be nice/expected to have DTS files licensed under BSD. I had no experience with BSD, so I started looking at this and the way kernel parts use it. Obviously Linux kernel is licensed under GPLv2, so all its code has to use GPLv2 compatible license. I found 3 BSD licenses in use by kernel code: 1) BSD 3-clause license 2) BSD 2-clause license 3) Clear BSD license Unfortunately in many cases (of source files) I wasn't able to clearly determine used BSD license. First of all, an accepted ident "Dual BSD/GPL" doesn't specify BSD version. All I can read in include/linux/module.h is "[GNU Public License v2 or BSD license choice]". It could mean any (of GPLv2 compatible) BSD versions. I guess ideally (in current situation) every file using "Dual BSD/GPL" should specify BSD license version in a header. However this isn't the case. 1) Some "Dual BSD/GPL" sources mention GPL in a header forgetting about BSD. Can we treat such files as BSD-licensed at all? Few examples: arch/arm/mach-pxa/am300epd.c drivers/fmc/fmc-trivial.c drivers/net/ppp/ppp_deflate.c drivers/scsi/a100u2w.c drivers/xen/xen-scsiback.c 2) Some "Dual BSD/GPL" sources don't specify BSD version in a header. E.g. all you can find in a header is "All rights reserved. Licensed under dual BSD/GPL license.". Two examples: drivers/char/pcmcia/cm4000_cs.c drivers/char/pcmcia/cm4040_cs.c Another problem is text of BSD license 1) Some BSD 2-clause licensed sources don't link to its content. In case of GPLv2 some sources simply mention this license and refer to COPYING. Few examples: a) drivers/bcma/main.c "Licensed under the GNU/GPL. See COPYING for details." b) drivers/block/umem.c "This driver is released to the public under the terms of the GNU GENERAL PUBLIC LICENSE version 2 c) drivers/mfd/tps6507x.c "For licencing details see kernel-base/COPYING" I believe the same could be done for BSD 2-clause license, however there is no file that can be pointed. It results in some sources specifying 2-clause license in a header without really providing the content. Example: arch/arm/boot/dts/lpc4350.dtsi 2) Some BSD 3-clause or Clear BSD licensed sources don't provide needed text Many templates of BSD 3-clause license I found contain <organization> that should be replaced by a proper organization/company. That makes me suspect we can't have a generic text of BSD 3-clause or Clear BSD in any shared file like COPYING. However there are sources that specify one of above licenses without providing or linking its text. Few examples: arch/blackfin/mach-bf609/include/mach/anomaly.h drivers/block/zram/zram_drv.c I'm wondering how we could improve this situation. I got 2 main ideas: 1) Extend MODULE_LICENSE We could add new acceptable entries specifying BSD version. We could try to improve checkpatch.pl to look for a full license in a header (it seems to be required as it has to provide <organization>). Maybe we could figure out (with some lawyers?) how to treat sources using "Dual BSD/GPL" mentioning GPL only (without BSD) in their header. 2) Get clear rules on how to write a header If you find extending MODULE_LICENSE a bad idea, maybe we can simply help people write proper headers. Explain the problem, provide examples, maybe add some check in checkpatch.pl. What do you think about this? -- Rafał -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
