On Thu, May 3, 2018 at 3:27 PM, Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > A number of platforms have a need to reduce the number of DT nodes, > mostly because of two similar constraints: the size of the DT blob, and > the time it takes to parse it. > > As the DT is used in more and more SoCs, and by more projects, some > constraints start to appear in bootloaders running from SRAM with an > order of magnitude of 10kB. A typical DT is in the same order of > magnitude, so any effort to reduce the blob size is welcome in such an > environment. > > Some platforms also want to reach very fast boot time, and the time it > takes to parse a typical DT starts to be noticeable. > > Both of these issues can be mitigated by reducing the number of nodes in > the DT. The biggest provider of nodes is usually the pin controller and > its subnodes, usually one for each valid pin configuration in a given > SoC. > > Obviously, a single, fixed, set of these nodes will be used by a given > board, so we can introduce a node property that will tell the DT > compiler to drop the nodes when they are not referenced in the tree, and > as such wouldn't be useful in the targetted system. > > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx> > > --- > Changes from v1: > - Rename the property from delete-if-unreferenced to omit-if-no-ref > - Change the various variables in the code to reflect this > - Added support to set the property on a label instead of a full node > - Also take into account the reference by path, and not only by > phandle > - Prune the unused nodes in a fixup pass, and not during the tree > flattening that allows to have the same behaviour when having an > output to a format other than dtb or asm > - Rebased on current master > --- > checks.c | 13 +++++++++++++ > dtc-lexer.l | 7 +++++++ > dtc-parser.y | 17 +++++++++++++++++ > dtc.h | 4 ++++ > livetree.c | 14 ++++++++++++++ > 5 files changed, 55 insertions(+) Not intimately familiar with some parts of this code, but FWIW: Reviewed-by: Rob Herring <robh@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe devicetree-compiler" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
