Enhanced the formerly private function _fdt_next_tag() to allow stepping through the tree, used to produce a human-readable dump, and made it part of the published interface. Also added some comments.

Signed-off-by: Gerald Van Baren vanbaren@cideas.com --- include/libfdt.h | 3 + libfdt/fdt.c | 39 --------------- libfdt/fdt_ro.c | 116 +++++++++++++++++++++++++++++++++++++++++++-- libfdt/fdt_rw.c | 6 +- libfdt/fdt_sw.c | 2 +- libfdt/fdt_wip.c | 4 +- libfdt/libfdt_internal.h | 1 - 7 files changed, 119 insertions(+), 52 deletions(-)

diff --git a/include/libfdt.h b/include/libfdt.h index acdc72e..c4b3c24 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -81,6 +81,9 @@ struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset, void *fdt_getprop(const void *fdt, int nodeoffset, const char *name, int *lenp);

+uint32_t fdt_next_tag(const void *fdt, int offset, + int *nextoffset, char **namep); + /* Write-in-place functions */ int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name, const void *val, int len); diff --git a/libfdt/fdt.c b/libfdt/fdt.c index 772da46..4b1c8ab 100644 --- a/libfdt/fdt.c +++ b/libfdt/fdt.c @@ -58,45 +58,6 @@ void *fdt_offset_ptr(const void *fdt, int offset, int len) return p; }

-uint32_t _fdt_next_tag(const void *fdt, int offset, int *nextoffset) -{ - const uint32_t *tagp, *lenp; - uint32_t tag; - const char *p; - - if (offset % FDT_TAGSIZE) - return -1; - - tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE); - if (! tagp) - return FDT_END; /* premature end */ - tag = fdt32_to_cpu(*tagp); - offset += FDT_TAGSIZE; - - switch (tag) { - case FDT_BEGIN_NODE: - /* skip name */ - do { - p = fdt_offset_ptr(fdt, offset++, 1); - } while (p && (*p != '\0')); - if (! p) - return FDT_END; - break; - case FDT_PROP: - lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp)); - if (! lenp) - return FDT_END; - /* skip name offset, length and value */ - offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp); - break; - } - - if (nextoffset) - *nextoffset = ALIGN(offset, FDT_TAGSIZE); - - return tag; -} - const char *_fdt_find_string(const char *strtab, int tabsize, const char *s) { int len = strlen(s) + 1; diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index 9112c6a..f884083 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -48,11 +48,24 @@ static int offset_streq(const void *fdt, int offset, return 1; }

+/* + * Return a pointer to the string at the given string offset. + */ char *fdt_string(const void *fdt, int stroffset) { return (char *)fdt + fdt_off_dt_strings(fdt) + stroffset; }

+/* + * Return the node offset of the node specified by: + * parentoffset - starting place (0 to start at the root) + * name - name being searched for + * namelen - length of the name: typically strlen(name) + * + * Notes: + * If the start node has subnodes, the subnodes are _not_ searched for the + * requested name. + */ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset, const char *name, int namelen) { @@ -62,13 +75,13 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,

CHECK_HEADER(fdt);

- tag = _fdt_next_tag(fdt, parentoffset, &nextoffset); + tag = fdt_next_tag(fdt, parentoffset, &nextoffset, NULL); if (tag != FDT_BEGIN_NODE) return -FDT_ERR_BADOFFSET;

do { offset = nextoffset; - tag = _fdt_next_tag(fdt, offset, &nextoffset); + tag = fdt_next_tag(fdt, offset, &nextoffset, NULL);

switch (tag) { case FDT_END: @@ -76,10 +89,15 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,

case FDT_BEGIN_NODE: level++; + /* + * If we are nested down levels, ignore the strings + * until we get back to the proper level. + */ if (level != 1) continue; + + /* Return the offset if this is "our" string. */ if (offset_streq(fdt, offset+FDT_TAGSIZE, name, namelen)) - /* Found it! */ return offset; break;

@@ -99,12 +117,19 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset, return -FDT_ERR_NOTFOUND; }

+/* + * See fdt_subnode_offset_namelen() + */ int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name) { return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name)); }

+/* + * Searches for the node corresponding to the given path and returns the + * offset of that node. + */ int fdt_path_offset(const void *fdt, const char *path) { const char *end = path + strlen(path); @@ -113,21 +138,33 @@ int fdt_path_offset(const void *fdt, const char *path)

CHECK_HEADER(fdt);

+ /* Paths must be absolute */ if (*path != '/') return -FDT_ERR_BADPATH;

while (*p) { const char *q;

+ /* Skip path separator(s) */ while (*p == '/') p++; if (! *p) return -FDT_ERR_BADPATH; + + /* + * Find the next path separator. The characters between + * p and q are the next segment of the the path to find. + */ q = strchr(p, '/'); if (! q) q = end;

+ /* + * Find the offset corresponding to the this path segment. + */ offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p); + + /* Oops, error, abort abort abort */ if (offset < 0) return offset;

@@ -137,6 +174,10 @@ int fdt_path_offset(const void *fdt, const char *path) return offset; }

+/* + * Given the offset of a node and a name of a property in that node, return + * a pointer to the property struct. + */ struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset, const char *name, int *lenp) @@ -155,14 +196,14 @@ struct fdt_property *fdt_get_property(const void *fdt, if (nodeoffset % FDT_TAGSIZE) goto fail;

- tag = _fdt_next_tag(fdt, nodeoffset, &nextoffset); + tag = fdt_next_tag(fdt, nodeoffset, &nextoffset, NULL); if (tag != FDT_BEGIN_NODE) goto fail;

do { offset = nextoffset;

- tag = _fdt_next_tag(fdt, offset, &nextoffset); + tag = fdt_next_tag(fdt, offset, &nextoffset, NULL); switch (tag) { case FDT_END: err = -FDT_ERR_TRUNCATED; @@ -177,6 +218,10 @@ struct fdt_property *fdt_get_property(const void *fdt, break;

case FDT_PROP: + /* + * If we are nested down levels, ignore the strings + * until we get back to the proper level. + */ if (level != 0) continue;

@@ -216,6 +261,10 @@ struct fdt_property *fdt_get_property(const void *fdt, return NULL; }

+/* + * Given the offset of a node and a name of a property in that node, return + * a pointer to the property data (ONLY). + */ void *fdt_getprop(const void *fdt, int nodeoffset, const char *name, int *lenp) { @@ -225,5 +274,60 @@ void *fdt_getprop(const void *fdt, int nodeoffset, if (! prop) return NULL;

- return prop->data; + return (void *)prop->data; +} + + +uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset, char **namep) +{ + const uint32_t *tagp, *lenp; + uint32_t tag; + const char *p; + + if (offset % FDT_TAGSIZE) + return -1; + + tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE); + if (! tagp) + return FDT_END; /* premature end */ + tag = fdt32_to_cpu(*tagp); + offset += FDT_TAGSIZE; + + switch (tag) { + case FDT_BEGIN_NODE: + if(namep) + *namep = fdt_offset_ptr(fdt, offset, 1); + + /* skip name */ + do { + p = fdt_offset_ptr(fdt, offset++, 1); + } while (p && (*p != '\0')); + if (! p) + return FDT_END; + break; + case FDT_PROP: + lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp)); + if (! lenp) + return FDT_END; + /* + * Get the property and set the namep to the name. + */ + if(namep) { + struct fdt_property *prop; + + prop = fdt_offset_ptr_typed(fdt, offset - FDT_TAGSIZE, prop); + if (! prop) + return -FDT_ERR_BADSTRUCTURE; + *namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff)); + } + /* skip name offset, length and value */ + offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp); + break; + } + + if (nextoffset) + *nextoffset = ALIGN(offset, FDT_TAGSIZE); + + return tag; } + diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c index 7396645..b33fbf4 100644 --- a/libfdt/fdt_rw.c +++ b/libfdt/fdt_rw.c @@ -145,7 +145,7 @@ static int _add_property(void *fdt, int nodeoffset, const char *name, int len, int namestroff; int err;

- tag = _fdt_next_tag(fdt, nodeoffset, &nextoffset); + tag = fdt_next_tag(fdt, nodeoffset, &nextoffset, NULL); if (tag != FDT_BEGIN_NODE) return -FDT_ERR_BADOFFSET;

@@ -219,10 +219,10 @@ int fdt_add_subnode_namelen(void *fdt, int parentoffset, return offset;

/* Try to place the new node after the parent's properties */ - _fdt_next_tag(fdt, parentoffset, &nextoffset); /* skip the BEGIN_NODE */ + fdt_next_tag(fdt, parentoffset, &nextoffset, NULL); /* skip the BEGIN_NODE */ do { offset = nextoffset; - tag = _fdt_next_tag(fdt, offset, &nextoffset); + tag = fdt_next_tag(fdt, offset, &nextoffset, NULL); } while (tag == FDT_PROP);

nh = _fdt_offset_ptr(fdt, offset); diff --git a/libfdt/fdt_sw.c b/libfdt/fdt_sw.c index 41d4891..672f4dd 100644 --- a/libfdt/fdt_sw.c +++ b/libfdt/fdt_sw.c @@ -203,7 +203,7 @@ int fdt_finish(void *fdt)

/* Walk the structure, correcting string offsets */ offset = 0; - while ((tag = _fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) { + while ((tag = fdt_next_tag(fdt, offset, &nextoffset, NULL)) != FDT_END) { if (tag == FDT_PROP) { struct fdt_property *prop = fdt_offset_ptr(fdt, offset, sizeof(*prop)); diff --git a/libfdt/fdt_wip.c b/libfdt/fdt_wip.c index 0db7d25..261b9b0 100644 --- a/libfdt/fdt_wip.c +++ b/libfdt/fdt_wip.c @@ -68,12 +68,12 @@ int _fdt_node_end_offset(void *fdt, int nodeoffset) uint32_t tag; int offset, nextoffset;

- tag = _fdt_next_tag(fdt, nodeoffset, &nextoffset); + tag = fdt_next_tag(fdt, nodeoffset, &nextoffset, NULL); if (tag != FDT_BEGIN_NODE) return -FDT_ERR_BADOFFSET; do { offset = nextoffset; - tag = _fdt_next_tag(fdt, offset, &nextoffset); + tag = fdt_next_tag(fdt, offset, &nextoffset, NULL);

switch (tag) { case FDT_END: diff --git a/libfdt/libfdt_internal.h b/libfdt/libfdt_internal.h index 124bef7..cc9633c 100644 --- a/libfdt/libfdt_internal.h +++ b/libfdt/libfdt_internal.h @@ -27,7 +27,6 @@ #define streq(p, q) (strcmp((p), (q)) == 0)

int _fdt_check_header(const void *fdt); -uint32_t _fdt_next_tag(const void *fdt, int startoffset, int *nextoffset); const char *_fdt_find_string(const char *strtab, int tabsize, const char *s); int _fdt_node_end_offset(void *fdt, int nodeoffset);