libfdt: Add fdt_node_offset_by_prop_value()
David Gibson
david at gibson.dropbear.id.au
Mon Sep 17 14:28:34 EST 2007
This patch adds a function to libfdt to locate nodes containing a
property with a specific value.
Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
Index: dtc/libfdt/fdt_ro.c
===================================================================
--- dtc.orig/libfdt/fdt_ro.c 2007-09-17 14:00:22.000000000 +1000
+++ dtc/libfdt/fdt_ro.c 2007-09-17 14:04:18.000000000 +1000
@@ -407,3 +407,54 @@ int fdt_parent_offset(const void *fdt, i
return fdt_supernode_atdepth_offset(fdt, nodeoffset,
nodedepth - 1, NULL);
}
+
+int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
+ const char *propname,
+ const void *propval, int proplen)
+{
+ uint32_t tag;
+ int offset, nextoffset;
+ const void *val;
+ int len;
+
+ CHECK_HEADER(fdt);
+
+ if (startoffset >= 0) {
+ tag = _fdt_next_tag(fdt, startoffset, &nextoffset);
+ if (tag != FDT_BEGIN_NODE)
+ return -FDT_ERR_BADOFFSET;
+ } else {
+ nextoffset = 0;
+ }
+
+ /* FIXME: The algorithm here is pretty horrible: we scan each
+ * property of a node in fdt_getprop(), then if that didn't
+ * find what we want, we scan over them again making our way
+ * to the next node. Still it's the easiest to implement
+ * approach; performance can come later. */
+ do {
+ offset = nextoffset;
+ tag = _fdt_next_tag(fdt, offset, &nextoffset);
+
+ switch (tag) {
+ case FDT_BEGIN_NODE:
+ val = fdt_getprop(fdt, offset, propname, &len);
+ if (val
+ && (len == proplen)
+ && (memcmp(val, propval, len) == 0))
+ return offset;
+ break;
+
+ case FDT_PROP:
+ case FDT_END:
+ case FDT_END_NODE:
+ case FDT_NOP:
+ break;
+
+ default:
+ return -FDT_ERR_BADSTRUCTURE;
+ }
+ } while (tag != FDT_END);
+
+ return -FDT_ERR_NOTFOUND;
+}
Index: dtc/libfdt/libfdt.h
===================================================================
--- dtc.orig/libfdt/libfdt.h 2007-09-17 14:00:04.000000000 +1000
+++ dtc/libfdt/libfdt.h 2007-09-17 14:00:23.000000000 +1000
@@ -146,6 +146,10 @@ int fdt_supernode_atdepth_offset(const v
int fdt_node_depth(const void *fdt, int nodeoffset);
int fdt_parent_offset(const void *fdt, int nodeoffset);
+int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
+ const char *propname,
+ const void *propval, int proplen);
+
/* Write-in-place functions */
int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
const void *val, int len);
Index: dtc/tests/Makefile.tests
===================================================================
--- dtc.orig/tests/Makefile.tests 2007-09-17 14:00:04.000000000 +1000
+++ dtc/tests/Makefile.tests 2007-09-17 14:00:23.000000000 +1000
@@ -1,5 +1,6 @@
LIB_TESTS_L = root_node find_property subnode_offset path_offset \
get_name getprop get_path supernode_atdepth_offset parent_offset \
+ node_offset_by_prop_value \
notfound \
setprop_inplace nop_property nop_node \
sw_tree1 \
Index: dtc/tests/node_offset_by_prop_value.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ dtc/tests/node_offset_by_prop_value.c 2007-09-17 14:00:23.000000000 +1000
@@ -0,0 +1,110 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Testcase for fdt_path_offset()
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdarg.h>
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "tests.h"
+#include "testdata.h"
+
+void vcheck_search(void *fdt, const char *propname, const void *propval,
+ int proplen, va_list ap)
+{
+ int offset = -1, target;
+
+ do {
+ target = va_arg(ap, int);
+ verbose_printf("Searching (target = %d): %d ->",
+ target, offset);
+ offset = fdt_node_offset_by_prop_value(fdt, offset, propname,
+ propval, proplen);
+ verbose_printf("%d\n", offset);
+
+ if (offset != target)
+ FAIL("fdt_node_offset_by_prop_value() returns %d "
+ "instead of %d", offset, target);
+ } while (target >= 0);
+}
+
+void check_search(void *fdt, const char *propname, const void *propval,
+ int proplen, ...)
+{
+ va_list ap;
+
+ va_start(ap, proplen);
+ vcheck_search(fdt, propname, propval, proplen, ap);
+ va_end(ap);
+}
+
+void check_search_str(void *fdt, const char *propname, const char *propval, ...)
+{
+ va_list ap;
+
+ va_start(ap, propval);
+ vcheck_search(fdt, propname, propval, strlen(propval)+1, ap);
+ va_end(ap);
+}
+
+#define check_search_val(fdt, propname, propval, ...) \
+ { \
+ typeof(propval) val = (propval); \
+ check_search((fdt), (propname), &val, sizeof(val), \
+ ##__VA_ARGS__); \
+ }
+
+int main(int argc, char *argv[])
+{
+ void *fdt;
+ int subnode1_offset, subnode2_offset;
+ int subsubnode1_offset, subsubnode2_offset;
+
+ test_init(argc, argv);
+ fdt = load_blob_arg(argc, argv);
+
+ subnode1_offset = fdt_path_offset(fdt, "/subnode1");
+ subnode2_offset = fdt_path_offset(fdt, "/subnode2");
+ subsubnode1_offset = fdt_path_offset(fdt, "/subnode1/subsubnode");
+ subsubnode2_offset = fdt_path_offset(fdt, "/subnode2/subsubnode");
+
+ if ((subnode1_offset < 0) || (subnode2_offset < 0)
+ || (subsubnode1_offset < 0) || (subsubnode2_offset < 0))
+ FAIL("Can't find required nodes");
+
+ check_search_val(fdt, "prop-int", TEST_VALUE_1, 0, subnode1_offset,
+ subsubnode1_offset, -FDT_ERR_NOTFOUND);
+
+ check_search_val(fdt, "prop-int", TEST_VALUE_2, subnode2_offset,
+ subsubnode2_offset, -FDT_ERR_NOTFOUND);
+
+ check_search_str(fdt, "prop-str", TEST_STRING_1, 0, -FDT_ERR_NOTFOUND);
+
+ check_search_str(fdt, "prop-str", "no such string", -FDT_ERR_NOTFOUND);
+
+ check_search_val(fdt, "prop-int", TEST_VALUE_1+1, -FDT_ERR_NOTFOUND);
+
+ check_search(fdt, "no-such-prop", NULL, 0, -FDT_ERR_NOTFOUND);
+
+ PASS();
+}
Index: dtc/tests/run_tests.sh
===================================================================
--- dtc.orig/tests/run_tests.sh 2007-09-17 14:00:04.000000000 +1000
+++ dtc/tests/run_tests.sh 2007-09-17 14:00:23.000000000 +1000
@@ -40,6 +40,7 @@ tree1_tests () {
run_test get_path $TREE
run_test supernode_atdepth_offset $TREE
run_test parent_offset $TREE
+ run_test node_offset_by_prop_value $TREE
run_test notfound $TREE
# Write-in-place tests
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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