c12b2b0c20 "libfdt: fdt_address_cells() and fdt_size_cells()" introduced
a bug as it consolidated code between the helpers for getting
#address-cells and #size-cells. Specifically #size-cells is allowed to
be 0, and is frequently found so in practice for /cpus. IEEE1275 only
requires implementations to handle 1..4 for #address-cells, although one
could make a case for #address-cells == #size-cells == 0 being used to
represent a bridge with a single port.
While we're there, it's not totally obvious that the existing implicit
cast of a u32 to int will give the correct results according to strict C,
although it does work in practice. Straighten that up to cast only after
we've made our range checks.
Reported-by: yonghuhaige via https://github.com/dgibson/dtc/issues/28
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Add internal fdt_cells() to avoid copy and paste. Test error cases and
default values. Fix typo in fdt_size_cells() documentation comment.
Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch makes a small start on libfdt functions which actually help to
parse the contents of device trees, rather than purely manipulating the
tree's structure.
We add simple helpers to read and sanity check the #address-cells and
#size-cells values for a given node.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
David Gibson