From: Thierry Reding <treding@xxxxxxxxxx>
Given a device tree node, a property name and an index, the new function
fdt_get_string_index() will return in an output argument a pointer to
the index'th string in the property's value.
The fdt_get_string() is a shortcut for the above with the index being 0.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
libfdt/fdt_ro.c | 30 ++++++++++++++++++++++++++++++
libfdt/libfdt.h | 27 +++++++++++++++++++++++++++
tests/strings.c | 24 ++++++++++++++++++++++++
3 files changed, 81 insertions(+)
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index aab3d1b94509..34f09d6c8c09 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -584,6 +584,36 @@ int fdt_find_string(const void *fdt, int nodeoffset, const char *property,
return -FDT_ERR_NOTFOUND;
}
+int fdt_get_string_index(const void *fdt, int nodeoffset, const char *property,
+ int index, const char **output)
+{
+ const char *list;
+ int length, i;
+
+ list = fdt_getprop(fdt, nodeoffset, property, &length);
+
+ for (i = 0; i < length; i++) {
+ int len = strlen(list);
+
+ if (index == 0) {
+ *output = list;
+ return 0;
+ }
+
+ list += len + 1;
+ i += len;
+ index--;
+ }
+
+ return FDT_ERR_NOTFOUND;
+}
+
+int fdt_get_string(const void *fdt, int nodeoffset, const char *property,
+ const char **output)
+{
+ return fdt_get_string_index(fdt, nodeoffset, property, 0, output);
+}
+
int fdt_node_check_compatible(const void *fdt, int nodeoffset,
const char *compatible)
{
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 34ab30dc3338..518550f1927d 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -888,6 +888,33 @@ int fdt_count_strings(const void *fdt, int nodeoffset, const char *property);
int fdt_find_string(const void *fdt, int nodeoffset, const char *property,
const char *string);
+/**
+ * fdt_get_string_index() - obtain the string at a given index in a string list
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of a tree node
+ * @property: name of the property containing the string list
+ * @index: index of the string to return
+ * @output: return location for the string
+ * @return: 0 if the string was found or a negative error code otherwise
+ */
+int fdt_get_string_index(const void *fdt, int nodeoffset, const char *property,
+ int index, const char **output);
+
+/**
+ * fdt_get_string() - obtain the first string in a string list
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of a tree node
+ * @property: name of the property containing the string list
+ * @output: return location for the string
+ * @return: 0 if the string was found or a negative error code otherwise
+ *
+ * This is a shortcut for:
+ *
+ * fdt_get_string_index(fdt, node, property, 0, output).
+ */
+int fdt_get_string(const void *fdt, int nodeoffset, const char *property,
+ const char **output);
+
/**********************************************************************/
/* Read-only functions (addressing related) */
/**********************************************************************/
diff --git a/tests/strings.c b/tests/strings.c
index 050230567468..e532e5fa8656 100644
--- a/tests/strings.c
+++ b/tests/strings.c
@@ -63,6 +63,26 @@ static void check_string_index(const void *fdt, const char *path,
path, err, index);
}
+static void check_string(const void *fdt, const char *path,
+ const char *property, int index,
+ const char *string)
+{
+ const char *result;
+ int offset, err;
+
+ offset = fdt_path_offset(fdt, path);
+ if (offset < 0)
+ FAIL("Couldn't find path %s", path);
+
+ err = fdt_get_string_index(fdt, offset, property, index, &result);
+ if (err < 0)
+ FAIL("Couldn't extract string: %d\n", err);
+
+ if (strcmp(string, result) != 0)
+ FAIL("String %d is %s instead of %s\n",
+ index, result, string);
+}
+
int main(int argc, char *argv[])
{
void *fdt;
@@ -82,5 +102,9 @@ int main(int argc, char *argv[])
check_string_index(fdt, "/device", "compatible", "baz", 1);
check_string_index(fdt, "/device", "big-endian", "bL", -1);
+ check_string(fdt, "/", "compatible", 0, "foo");
+ check_string(fdt, "/device", "compatible", 0, "bar");
+ check_string(fdt, "/device", "compatible", 1, "baz");
+
PASS();
}
--
2.4.5
--
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