libfdt: Enhanced and published fdt_next_tag()
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.
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
/* 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 @@
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);