On Wed, 14 Aug 2013, Tom Rini wrote: > On Wed, Aug 14, 2013 at 10:44:22AM -0600, Stephen Warren wrote: > > On 08/14/2013 09:13 AM, Tom Rini wrote: > > > Hey all, > > > > > > Do we have a document yet talking about the best practices for how we > > > would like a hardware vendor to ship, store and possibly update a device > > > tree, on the hardware? "However they like" seems likely to invite > > > problems down the line with everyone trying their own thing. Thanks! > > > > I don't believe there's any written guidance, no. > > > > The initial guidance Grant gave (IIRC at the first Linaro Connect last > > year, or perhaps the ARM workshop in Prague, or perhaps also in various > > ARM kernel list threads?) was that the DTBs should be stored/accessed in > > exactly the same way as the kernel, which on many systems implies it's a > > file in /boot (although MTD partitions, ... are also possible kernel > > locations). The idea here was to explicitly make upgrading the DTB as > > easy as upgrading the kernel, and explicitly without having to upgrade > > any firmware, since that's a more dangerous process in most cases. > > > > Now perhaps that advice was only intended to apply very early on when DT > > was really new on ARM, and has "aged out" by now? If so, I don't recall > > that every being explicitly mentioned or communicated later. > [snip out a bit more of Stephen's answer] > > Yes, this notion certainly is the opposite of what was suggested on the > cross-distro list, both as part of a "what should a bootloader provide > to get commodity distros to support the board" thread and the "where > should a device tree live in the filesystem" thread. Cc'ing them now > because this is one of those things that feels like it needs solving, > solving soon, and done in a way the least number of folks get surprised > about it. I don't think the "however they like" approach is that bad. It is certainly less of a problem than "exactly the same way as the kernel" is. Using /boot implies a distro filesystem and we'd rather wish for DT to be independent from a distro or even Linux. The DTB should therefore be stored and accessed in a way which is hardware/bootloader specific. The distro being installed on top shouldn't have to care. Nicolas -- 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
