For ages, we've been talking about adding functions to libfdt to allow
iteration through properties. So, finally, here are some.
I got bogged down on this for a long time because I didn't want to
expose offsets directly to properties to the callers. But without
that, attempting to make reasonable iteration functions just became
horrible. So eventually, I settled on an interface which does now
expose property offsets. fdt_first_property_offset() and
fdt_next_property_offset() are used to step through the offsets of the
properties starting from a particularly node offset. The details of
the property at each offset can then be retrieved with either
fdt_get_property_by_offset() or fdt_getprop_by_offset() which have
interfaces similar to fdt_get_property() and fdt_getprop()
respectively.
No explicit testcases are included, but we do use the new functions to
reimplement the existing fdt_get_property() function.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, the Linux kernel, libfdt and dtc, when using flattened
device trees encode a node's phandle into a property named
"linux,phandle". The ePAPR specification, however - aiming as it is
to not be a Linux specific spec - requires that phandles be encoded in
a property named simply "phandle".
This patch adds support for this newer approach to dtc and libfdt.
Specifically:
- fdt_get_phandle() will now return the correct phandle if it
is supplied in either of these properties
- fdt_node_offset_by_phandle() will correctly find a node with
the given phandle encoded in either property.
- By default, when auto-generating phandles, dtc will encode
it into both properties for maximum compatibility. A new -H
option allows either only old-style or only new-style
properties to be generated.
- If phandle properties are explicitly supplied in the dts
file, dtc will not auto-generate ones in the alternate format.
- If both properties are supplied, dtc will check that they
have the same value.
- Some existing testcases are updated to use a mix of old and
new-style phandles, partially testing the changes.
- A new phandle_format test further tests the libfdt support,
and the -H option.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, callers of fdt_next_tag() must usually follow the call with
some sort of call to fdt_offset_ptr() to verify that the blob isn't
truncated in the middle of the tag data they're going to process.
This is a bit silly, since fdt_next_tag() generally has to call
fdt_offset_ptr() on at least some of the data following the tag for
its own operation.
This patch alters fdt_next_tag() to always use fdt_offset_ptr() to
verify the data between its starting offset and the offset it returns
in nextoffset. This simplifies fdt_get_property() which no longer has
to verify itself that the property data is all present.
At the same time, I neaten and clarify the error handling for
fdt_next_tag(). Previously, fdt_next_tag() could return -1 instead of
a tag value in some circumstances - which almost none of the callers
checked for. Also, fdt_next_tag() could return FDT_END either because
it encountered an FDT_END tag, or because it reached the end of the
structure block - no way was provided to tell between these cases.
With this patch, fdt_next_tag() always returns FDT_END with a negative
value in nextoffset for an error. This means the several places which
loop looking for FDT_END will still work correctly - they only need to
check for errors at the end. The errors which fdt_next_tag() can
report are:
- -FDT_ERR_TRUNCATED if it reached the end of the structure
block instead of finding a tag.
- -FDT_BADSTRUCTURE if a bad tag was encountered, or if the
tag data couldn't be verified with fdt_offset_ptr().
This patch also updates the callers of fdt_next_tag(), where
appropriate, to make use of the new error reporting.
Finally, the prototype for the long gone _fdt_next_tag() is removed
from libfdt_internal.h.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently fdt_next_node() will find the next node in the blob
regardless of whether it is above, below or at the same level in the
tree as the starting node - the depth parameter is updated to indicate
which is the case. When a depth parameter is supplied, this patch
makes it instead terminate immediately when it finds the END_NODE tag
for a node at depth 0. In this case it returns the offset immediately
past the END_NODE tag.
This has a couple of advantages. First, this slightly simplifies
fdt_subnode_offset(), which no longer needs to explicitly check that
fdt_next_node()'s iteration hasn't left the starting node. Second,
this allows fdt_next_node() to be used to implement
_fdt_node_end_offset() considerably simplifying the latter function.
The other users of fdt_next_node() either don't need to iterate out of
the starting node, or don't pass a depth parameter at all. Any
callers that really need to iterate out of the starting node, but keep
tracking depth can do so by biasing the initial depth value.
This is a semantic change, but I think it's very unlikely to break any
existing library users.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
There's currently an off-by-one bug in fdt_subnode_offset_namelen()
which causes it to keep searching after it's finished the subnodes of
the given parent, and into the subnodes of siblings of the original
node which come after it in the tree.
This patch fixes the bug. It also extends the subnode_offset testcase
(updating all of the 'test_tree1' example trees in the process) to
catch it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Kumar has already added alias expansion to fdt_path_offset().
However, in some circumstances it may be convenient for the user of
libfdt to explicitly get the string expansion of an alias. This patch
adds a function to do this, fdt_get_alias(), and uses it to implement
fdt_path_offset().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The current implementation of fdt_get_path() has a couple of bugs,
fixed by this patch.
First, contrary to its documentation, on success it returns the length
of the node's path, rather than 0. The testcase is correspondingly
wrong, and the patch fixes this as well.
Second, in some circumstances, it will return -FDT_ERR_BADOFFSET
instead of -FDT_ERR_NOSPACE when given insufficient buffer space.
Specifically this happens when there is insufficient space even to
hold the path's second last component. This behaviour is corrected,
and the testcase updated to check it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
If the path doesn't start with '/' check to see if it matches some alias
under "/aliases" and substitute the matching alias value in the path
and retry the lookup.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
As well as fdt_subnode_offset(), libfdt includes an
fdt_subnode_offset_namelen() function that takes the subnode name to
look up not as a NUL-terminated string, but as a string with an
explicit length. This can be useful when the caller has the name as
part of a longer string, such as a full path.
However, we don't have corresponding 'namelen' versions for
fdt_get_property() and fdt_getprop(). There are less obvious use
cases for these variants on property names, but there are
circumstances where they can be useful e.g. looking up property names
which need to be parsed from a longer string buffer such as user input
or a configuration file, or looking up an alias in a path with
IEEE1275 style aliases.
So, since it's very easy to implement such variants, this patch does
so. The original NUL-terminated variants are, of course, implemented
in terms of the namelen versions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
In commit b6d80a20fc, we renamed all
libfdt functions to be prefixed with fdt_ or _fdt_ to minimise the
chance of collisions with things from whatever package libfdt is
embedded in, pulled into the libfdt build via that environment's
libfdt_env.h.
Except... I missed one. This patch applies the same treatment to
_stringlist_contains(). While we're at it, also make it static since
it's only used in the same file.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
libfdt is supposed to easy to embed in projects all and sundry.
Often, it won't be practical to separate the embedded libfdt's
namespace from that of the surrounding project. Which means there can
be namespace conflicts between even libfdt's internal/static functions
and functions or macros coming from the surrounding project's headers
via libfdt_env.h.
This patch, therefore, renames a bunch of libfdt internal functions
and macros and makes a few other chances to reduce the chances of
namespace collisions with embedding projects. Specifically:
- Internal functions (even static ones) are now named _fdt_*()
- The type and (static) global for the error table in
fdt_strerror() gain an fdt_ prefix
- The unused macro PALIGN is removed
- The memeq and streq macros are removed and open-coded in the
users (they were only used once each)
- Other macros gain an FDT_ prefix
- To save some of the bulk from the previous change, an
FDT_TAGALIGN() macro is introduced, where FDT_TAGALIGN(x) ==
FDT_ALIGN(x, FDT_TAGSIZE)
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Enabling -Wcast-qual warnings in dtc shows up a number of places where
we are incorrectly discarding a const qualification. There are also
some places where we are intentionally discarding the 'const', and we
need an ugly cast through uintptr_t to suppress the warning. However,
most of these are pretty well isolated with the *_w() functions. So
in the interests of maximum safety with const qualifications, this
patch enables the warnings and fixes the existing complaints.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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>
This patch makes a couple of small cleanups to parameter checking of
libfdt functions.
- In several functions which take a node offset, we use an
idiom involving fdt_next_tag() first to check that we have indeed been
given a node offset. This patch adds a helper function
_fdt_check_node_offset() to encapsulate this usage of fdt_next_tag().
- In fdt_rw.c in several places we have the expanded version
of the RW_CHECK_HEADER() macro for no particular reason. This patch
replaces those instances with an invocation of the macro; that's what
it's for.
- In fdt_sw.c we rename the check_header_sw() function to
sw_check_header() to match the analgous function in fdt_rw.c, and we
provide an SW_CHECK_HEADER() wrapper macro as RW_CHECK_HEADER()
functions in fdt_rw.c
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Since fdt_node_offset_by_compatible() was converted to the new
fdt_next_node() iterator, a chunk of initialization code became
redundant, but was not removed by oversight. This patch cleans it up.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently the CHECK_HEADER() macro is defined local to fdt_ro.c.
However, there are a handful of functions (fdt_move, rw_check_header,
fdt_open_into) from other files which could also use it (currently
they open-code something more-or-less identical). Therefore, this
patch moves CHECK_HEADER() to libfdt_internal.h and uses it in those
places.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds an fdt_next_node() function which can be used to
iterate through nodes of the tree while keeping track of depth. This
function is used to simplify the iteration code in a lot of other
functions, and is also exported for use by library users.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The fdt_offset_ptr_typed() macro seemed like a good idea at the time.
However, it's not actually used all that often, it can silently throw
away const qualifications and it uses a gcc extension (typeof) which
I'd prefer to avoid for portability.
Therefore, this patch gets rid of it (and the fdt_offset_ptr_typed_w()
variant which was never used at all). It also makes a few variables
const in testcases, which always should have been const, but weren't
caught before because of the aforementioned silent discards.
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>
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>
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>
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>
This large patch removes all trailing whitespace from dtc (including
libfdt, the testsuite and documentation). It also removes a handful
of redundant blank lines (at the end of functions, or when there are
two blank lines together for no particular reason).
As well as anything else, this means that quilt won't whinge when I go
to convert the whole of libfdt into a patch to apply to the kernel.
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>
With kernel commit eff2ebd207af9f501af0ef667a7d14befcb36c1b, we
clarified that in the flattened tree format, a particular nodes
properties are required to precede its subdnodes.
At present however, both dtc and libfdt will process trees which don't
meet this condition. This patch simplifies the code for
fdt_get_property() based on assuming that constraint. dtc continues
to be able to handle such an invalid tree - on the grounds that it's
useful for dtc to be able to correct such a broken tree - but this
patch adds a warning when this condition is not met while reading a
flattened tree.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
My recent implemenetation of fdt_get_path() had a bug - the while loop
tested offset which was unitialized on the first iteration. Depending
on code surrounding the call, this could cause fdt_get_path() to
return incorrect results.
This patch corrects the problem by applying some more correct thinking
to the loop condition.
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>
Currently, fdt_path_offset() returns FDL_ERR_BADOFFSET if given a path
with a trailing '/'. In particular this means that
fdt_path_offset("/") returns FDT_ERR_BADOFFSET rather than 0 as one
would expect.
This patch fixes the function to accept and ignore trailing '/'
characters. As well as allowing fdt_path_offset("/") this means that
fdt_path_offset("/foo/") will return the same as
fdt_path_offset("/foo") which seems in keeping with the principle of
least surprise.
This also adds a testcase to ensure that fdt_path_offset("/") returns
0 as it should.
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>
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>
The libfdt functions are supposed to behave tolerably well when practical,
even if given a corrupted device tree as input. A silly mistake in
fdt_get_property() means we're bounds checking against the size of a pointer
instead of the size of a property header, meaning we can get bogus
behaviour in a corrupted device tree where the structure block ends in
what's supposed to be the middle of a property.
This patch corrects the problem (fdt_get_property() will now return
BADSTRUCTURE in this case), and also adds a testcase to catch the bug.
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 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