On Tue, 3 Oct 2017, Rob Herring wrote: > For static DT usecases, we don't need the disabled nodes and can skip > unflattening. This saves a significant amount of RAM in memory constrained > cases. In one example on STM32F469, the RAM usage goes from 118K to 26K. > > There are a few cases in the kernel that modify the status property > dynamically. These all are changes from enabled to disabled, depend on > OF_DYNAMIC or are not FDT based (PDT based). > > Cc: Nicolas Pitre <nicolas.pi...@linaro.org> > Cc: Frank Rowand <frowand.l...@gmail.com> > Signed-off-by: Rob Herring <r...@kernel.org>
Tested-by: Nicolas Pitre <n...@linaro.org> > --- > For more background, see this presentation from Nico: > > https://connect.linaro.org/resource/sfo17/sfo17-100/ Oh my ... this is horrible ... /me hides in shame > > drivers/of/fdt.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index f8c39705418b..efe91c6856a0 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -396,6 +396,10 @@ static int unflatten_dt_nodes(const void *blob, > if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH)) > continue; > > + if (!IS_ENABLED(CONFIG_OF_DYNAMIC) && > + !of_fdt_device_is_available(blob, offset)) > + continue; > + > if (!populate_node(blob, offset, &mem, nps[depth], > &nps[depth+1], dryrun)) > return mem - base; > -- > 2.11.0 > >
