In a number of places through libfdt and its tests, we have *_typed()
macro variants on functions which use gcc's typeof and statement
expression extensions to allow passing literals where the underlying
function takes a buffer and size.
These seemed like a good idea at the time, but in fact they have some
problems. They use typeof and statement expressions, extensions I'd
prefer to avoid for portability. Plus, they have potential gotchas -
although they'll deal with the size of the thing passed, they won't
deal with other representation issues (like endianness) and results
could be very strange if the type of the expression passed isn't what
you think it is.
In fact, the only users of these _typed() macros were when the value
passed is a single cell (32-bit integer). Therefore, this patch
removes all these _typed() macros and replaces them with explicit
_cell() variants which handle a single 32-bit integer, and which also
perform endian convesions as appropriate.
With this in place, it now becomes easy to use standardized big-endian
representation for integer valued properties in the testcases,
regardless of the platform we're running on. We therefore do that,
which has the additional advantage that all the example trees created
during a test run are now byte-for-byte identical regardless of
platform.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
At present, the fdt_subnode_offset() and fdt_path_offset() functions
in libfdt require the exact name of the nodes in question be passed,
including unit address.
This is contrary to traditional OF-like finddevice() behaviour, which
allows the unit address to be omitted (which is useful when the device
name is unambiguous without the address).
This patch introduces similar behaviour to
fdt_subnode_offset_namelen(), and hence to fdt_subnode_offset() and
fdt_path_offset() which are implemented in terms of the former. The
unit address can be omitted from the given node name. If this is
ambiguous, the first such node in the flattened tree will be selected
(this behaviour is consistent with IEEE1275 which specifies only that
an arbitrary node matching the given information be selected).
This very small change is then followed by many more diffs which
change the test examples and testcases to exercise this behaviour.
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, libfdt functions returning a structure offset return a
zero-or-positive offset on success, and return a negative error code
on failure. Functions which only return an error code return a
positive version of the error code, or 0 on success.
This patch improves consistency by always returning negative error
codes on failure, for both types of function. With this change, we do
away with the special fdt_offset_error() macro for checking whether a
returned offset value is an error and extracting the encoded error
value within. Instead an explicit (ret_value < 0) is now the
preferred way of checking return values for both offset-returning and
error-code-returning functions.
The fdt_strerror() function in the test code is updated
correspondingly to make more sense with the new conventions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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