Commit 77ea8a68 authored Oct 03, 2017 by Rob Herring

of/fdt: skip unflattening of disabled nodes



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).

Tested-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>

parent ecc8a96e

drivers/of/fdt.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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_KOBJ) &&
		!of_fdt_device_is_available(blob, offset))
		continue;

		if (!populate_node(blob, offset, &mem, nps[depth],
		&nps[depth+1], dryrun))
		return mem - base;