This patch turns on the -Wpointer-arith option in the dtc Makefile,
and fixes the resulting warnings due to using (void *) in pointer
arithmetic. While convenient, pointer arithmetic on void * is not
portable, so it's better that we avoid it, particularly in libfdt.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
At present fdt.h #includes stdint.h. This makes some sense, because fdt.h
uses the standard fixed-width integer types. However, this can make life
difficult when building in different environments which may not have a
stdint.h. Therefore, this patch removes the #include from fdt.h, instead
requiring that users of fdt.h define the fixed-width integer types before
including fdt.h, either by themselves including stdint.h, or by any other
means.
At present, the blob containing a device tree is passed to the various
fdt_*() functions as a (struct fdt_header *) i.e. a pointer to the
header structure at the beginning of the blob.
This patch changes all the functions so that they instead take a (void
*) pointing to the blob. Under some circumstances can avoid the need
for the caller to cast a blob pointer into a (struct fdt_header *)
before passing it to the fdt_*() functions.
Using a (void *) also reduce the temptation for users of the library
to directly dereference toe (struct fdt_header *) to access header
fields. Instead they must use the fdt_get_header() or
fdt_set_header() macros, or the fdt_magic(), fdt_totalsize()
etc. wrappers around them which are safer, since they will always
handle endian conversion.
With this change, the whole-tree moving, or manipulating functions:
fdt_move(), fdt_open_into() and fdt_pack() no longer need to return a
pointer to the "new" tree. The given (void *) buffer pointer they
take can instead be used directly by the caller as the new tree.
Those functions are thus changed to instead return an error code
(which in turn reduces the number of functions using the ugly encoding
of error values into pointers).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
David Gibson