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>
This patch adds fdt_get_phandle() and fdt_node_offset_by_phandle()
functions to libfdt. fdt_get_phandle() will retreive the phandle
value of a given node, and fdt_node_offset_by_phandle() will locate a
node given a phandle.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch documents a few more functions in libfdt.h. All the
read-only functions are now documented.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch documents a few more functions in libfdt.h. It also makes
a slight update to the description of the FDT_ERR_INTERNAL error code.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
libfdt: Add more documentation (patch the third)
This patch adds documentation in libfdt.h for a few more libfdt
functions. It also makes a slight update to the documentation of
fdt_get_name().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently all the read/write functions in libfdt require that the
given tree be v17, and further, that the tree has the memory
reservation block, structure block and strings block stored in that
physical order.
This patch eases these constraints, by making fdt_open_int() reorder
the blocks, and/or convert the tree to v17, so that it will then be
ready for the other read-write functions.
It also extends fdt_pack() to actually remove any gaps between blocks
that might be present.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The fdt_set_header() macro casts an arbitrary pointer into (struct
fdt_header *) to set fdt header fields. While we need to change the
type, so that we can use this macro on the usual (void *) used to
represent a device tree blob, the current macro also casts away any
const on the input pointer, which loses an important check.
This patch replaces the fdt_set_header() macro with a set of inline
functions, one for each header field which do a similar thing, but
which won't silently remove const from a given pointer. This approach
is also more in keeping with the individual accessor macros we use for
reading fdt header fields.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds some internal documentation in libfdt.h, in the form
of comments on the error codes and some functions. Only a couple of
functions are covered so far, leaving the documentation still woefully
inadequate, but hey, it's a start.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Although it's a low-level function that shouldn't normally be needed,
there are circumstances where it's useful for users of libfdt to use
the _fdt_next_tag() function. Therefore, this patch renames it to
fdt_next_tag() and publishes it in libfdt.h.
In addition, this patch adds a new testcase using fdt_next_tag(),
dtbs_equal_ordered. This testcase tests for structural equality of
two dtbs, including the order of properties and subnodes, but ignoring
NOP tags, the order of the dtb sections and the layout of strings in
the strings block. This will be useful for testing other dtc
functionality in the future.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
It's potentially useful for users of libfdt to sanity check a device
tree (or, rather, a blob of data which may or may not be a device
tree) before processing it in more detail with libfdt.
This patch renames the libfdt internal function _fdt_check_header() to
fdt_check_header() and makes it a published function, so it can now be
used for this purpose.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, fdt_string() returns a (non-const) char *, despite taking a
const void *fdt. This is inconsistent with all the other read-only
functions which all return const pointers into the blob.
This patch fixes that.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds functions for dealing with the compatible property.
fdt_node_check_compatible() can be used to determine whether a node is
compatible with a given string and fdt_node_offset_by_compatible()
locates nodes with a given compatible string.
Testcases for these functions are also included.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
libfdt.h currently includes fdt.h, then libfdt_env.h. This is
incorrect, because depending on the environment into which libfdt is
embedded, libfdt_env.h may be needed to define datatypes used in
fdt.h. This patch corrects the problem.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds functions to libfdt for accessing the memory
reservation map section of a device tree blob. fdt_num_mem_rsv()
retreives the number of reservation entries in a dtb, and
fdt_get_mem_rsv() retreives a specific reservation entry.
fdt_add_mem_rsv() adds a new entry, and fdt_del_mem_rsv() removes a
specific numbered entry.
Testcases for these new functions are also included.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds a function to libfdt to locate nodes containing a
property with a specific value.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds an fdt_parent_offset() function which returns an
offset to the parent node of a given node. It also adds two helper
functions which are used to implement fdt_parent_offset() but are also
exported: fdt_supernode_atdepth_offset() which returns the ancestor of
a given node at a specified depth from the root of the tree, and
fdt_node_depth() which returns the depth of a given node.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds an fdt_get_path() function to libfdt, which returns
the full path of a given node in a caller supplied buffer.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds a new fdt_get_name() function to libfdt which will
return a node's name string (including unit address, if any).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
As a read-only functions, which take a const pointer to the fdt, treat
fdt_get_property() and fdt_getprop() as returning const pointers to
within the blob. fdt_get_property_w() and fdt_getprop_w() versions
are supplied which take a non-const fdt pointer and return a non-const
pointer for the benefit of callers wishing to alter the device tree
contents.
Likewise the lower-level fdt_offset_ptr() and _fdt_offset_ptr()
functions are changed to return const pointers, with *_w() versions
supplied.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This function moves the fdt_strerror() function, currently found in
the test code into the fdt library proper. This makes life easier for
any library users who want to provide meaningful error messages. The
function goes into a module of its own, so that users who don't need
the function won't get a copy of it linked in.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
First, this patch removes several underused error codes:
FDT_ERR_BADPOINTER and FDT_ERR_BADHEADER were not used at all and are
simply removed. FDT_ERR_SIZE_MISMATCH was very similar in spirit to
FDT_ERR_NOSPACE, and used only in circumstances where there can be no
confusion between the two, so is removed and folded into
FDT_ERR_NOSPACE. FDT_ERR_INTERAL was used on only one place, on a
"can't happen" check. It seems of little value so the check and error
code are removed also.
Second, the error codes have been re-numbered and grouped roughly by
severity. That is codes which can reasonably occur in normal
operation separated from those which indicate bad parameters (and
therefore a bug in the caller) or a bad or corrupted device tree blob.
Third the test function fdt_strerror() is cleaned up a little based on
these changes.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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>
This patch abolishes the non-standard and confusing encoding of errors
into pointer return values. The only functions still returning such a
potentially encoded pointer are fdt_get_property() and fdt_getprop().
Those functions also return a length via an (int *). With this patch
those functions instead now return NULL on any error, and return the
code indicating the type of error in the length paramater.
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>
fdt_property_offset() is the only function in the library returning a
direct offset to a property, and no function takes such an offset
(they only take offsets to nodes, not properties). Furthermore the
only client uses for this function I can think of involve immediately
translating the offset into a pointer, effectively duplicating the
internal function _fdt_getprop()
This function abolishes fdt_property_offset(), replacing it with
fdt_get_property(), a renamed and now externally visible version of
_fdt_getprop().
This patch fixes a number of embarrasing oversights which meant libfdt
did not work correctly on little endian machines. With this patch the
testsuite now passes on x86. Device trees are always created
big-endian.
v17 of the blob format adds a field for the size of the structure
block, but is backwards compatible with v16. This patch introduces
definitions for the new field, and uses it to improve the bounds
checking in the read-only code. It also cleans up the sequential
write code using it: we no longer need to borrow the version field as
a write pointer.
This patch adds exported accessor macros for the various flat device
tree header fields to libfdt.h. This necessitates moving some of the
byte-swapping functions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The range sanity checking on the fdt_string_cmp() function causes problems
for the sequential write code (or at least for using RO functions on an
incomplete SW tree). Plus they didn't really fit with the philosphy for
the RO code of working as widely as possible on weirdly constructed trees.
David Gibson