Dear Stephen Warren, > On 06/01/2012 12:38 AM, Igor Grinberg wrote: > > On 05/31/12 19:50, Stephen Warren wrote: > >> On 05/31/2012 04:13 AM, Marek Vasut wrote: > >>> Dear Igor Grinberg, > >>> > >>>> On 05/30/12 19:45, Stephen Warren wrote: > >>>>> From: Stephen Warren <swar...@nvidia.com> > >>>>> > >>>>> Fix the .dts file USB unit addresses not to duplicate each-other. > >>>>> > >>>>> Fix the board name string to indicate the vendor is Compulab not > >>>>> NVIDIA. > >>>>> > >>>>> Signed-off-by: Stephen Warren <swar...@nvidia.com> > >>>> > >>>> Acked-by: Igor Grinberg <grinb...@compulab.co.il> > >>> > >>> Do we have one copy of the dts files here and one in Linux kernel tree? > >>> Are they the same? > >> > >> Both U-Boot and the kernel have their own copies of the .dts files. > >> > >> In general, the U-Boot copy would be identical to what's in the kernel, > >> or a pure subset since mostly the kernel's driver support is more > >> advanced, so we've added more nodes to the DT. > >> > >> That said, there are unfortunately some bizarre quirks in the way the > >> U-Boot parses the device tree, such as requiring the /aliases node in > >> order to enumerate at least some devices, the use of the Tegra clock > >> binding that hasn't been incorporated into the kernel yet and is used > >> for both clock and module reset functionality even though it's really > >> only intended for clock functionality, and various other small > >> properties that are U-Boot specific (although I forget if we managed to > >> eliminate these all or not). These all end up causing differences > >> between the two device tree files:-( > > > > Thanks for the information. > > > > I don't see any problem with having differences between the .dts files > > > in kernel and U-Boot, because the way I see it: > The issue isn't so much the duplicate files, but differing content. > > The whole point about DT is that it's a pure representation of the > hardware; there should be no software-dependent design or data in it. > Put another way, both U-Boot and the Linux kernel (and indeed anything > else) should expect the DT to be written according to the same > "bindings" design. This doesn't preclude the U-Boot DT file being a > strict subset of the kernel file it it needs less information, but what > is in both should match.
Thanks for clearing it up! > > > Also, IIRC, the intension was to remove the kernel .dts files after > > "all bootloaders" know to boot the DT kernel... > > I don't believe it's anything to do with bootloaders. Bootloaders are > already (in the main) expected to provide the DTB to the kernel as a > separate entity, irrespective of whether the DTB is built by the kernel > boot process or from some other repository. (Although there is > CONFIG_APPENDED_DTB to support cases where this isn't possible, it's > much preferred not to use this). Moving the .dts files out of the kernel > is more purely about finding a place to put them I think. > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
