[PATCH v5 4/5] Add fdtget utility to read property values from a device tree
Simon Glass
sjg at chromium.org
Fri Sep 23 03:11:05 EST 2011
This simply utility makes it easy for scripts to read values from the device
tree. It is written in C and uses the same libfdt as the rest of the dtc
package.
What is it for:
- Reading fdt values from scripts
- Extracting fdt information within build systems
- Looking at particular values without having to dump the entire tree
To use it, specify the fdt binary file on command line followed by a list of
node, property pairs. The utility then looks up each node, finds the property
and displays the value.
Each value is printed on a new line.
fdtget tries to guess the type of each property based on its contents. This
is not always reliable, so you can use the -t option to force fdtget to decode
the value as a string, or byte, etc.
To read from stdin, use - as the file.
Usage:
fdtget <options> <dt file> [<node> <property>]...
Options:
-t <type> Type of data
-h Print this help
<type> s=string, i=int, u=unsigned, x=hex
Optional modifier prefix:
hh or b=byte, h=2 byte, l=4 byte (default)
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v2:
- Separate arguments for node and property
- Merge two related commits into this one
- Use structure for storing display options
- Remove use of getopt_long()
- Adjust tests for new fdtget arguments
Changes in v3:
- Squash fdtget test commit into fdtget
- Add a few more tests for 1- and 2-byte formats
- Change format of -t argument to be more like printf
- Change help string and make part of it common
- Add error checking for the property not being a multiple of value size
.gitignore | 1 +
Makefile | 4 +
Makefile.utils | 7 ++
fdtget.c | 226 +++++++++++++++++++++++++++++++++++++++++++++++
tests/fdtget-runtest.sh | 35 +++++++
tests/run_tests.sh | 43 +++++++++-
tests/tests.sh | 1 +
util.h | 10 ++
8 files changed, 326 insertions(+), 1 deletions(-)
create mode 100644 fdtget.c
create mode 100755 tests/fdtget-runtest.sh
diff --git a/.gitignore b/.gitignore
index ae7a46a..9f27f34 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,4 @@ lex.yy.c
/ftdump
/convert-dtsv0
/version_gen.h
+/fdtget
diff --git a/Makefile b/Makefile
index b32409b..00e137a 100644
--- a/Makefile
+++ b/Makefile
@@ -110,6 +110,7 @@ include Makefile.utils
BIN += convert-dtsv0
BIN += dtc
BIN += ftdump
+BIN += fdtget
SCRIPTS = dtdiff
@@ -120,6 +121,7 @@ ifneq ($(DEPTARGETS),)
-include $(DTC_OBJS:%.o=%.d)
-include $(CONVERT_OBJS:%.o=%.d)
-include $(FTDUMP_OBJS:%.o=%.d)
+-include $(FDTGET_OBJS:%.o=%.d)
endif
@@ -180,6 +182,8 @@ convert-dtsv0: $(CONVERT_OBJS)
ftdump: $(FTDUMP_OBJS)
+fdtget: $(FDTGET_OBJS) $(LIBFDT_archive)
+
#
# Testsuite rules
diff --git a/Makefile.utils b/Makefile.utils
index 0ed9297..095cacd 100644
--- a/Makefile.utils
+++ b/Makefile.utils
@@ -8,3 +8,10 @@ FTDUMP_SRCS = \
util.c
FTDUMP_OBJS = $(FTDUMP_SRCS:%.c=%.o)
+
+
+FDTGET_SRCS = \
+ fdtget.c \
+ util.c
+
+FDTGET_OBJS = $(FDTGET_SRCS:%.c=%.o)
diff --git a/fdtget.c b/fdtget.c
new file mode 100644
index 0000000..48ab615
--- /dev/null
+++ b/fdtget.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <ctype.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <libfdt.h>
+
+#include "util.h"
+
+/* Holds information which controls our output and options */
+struct display_info {
+ int type; /* data type (s/i/u/x or 0 for default) */
+ int size; /* data size (1/2/4) */
+};
+
+static void report_error(const char *where, int err)
+{
+ fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
+}
+
+/**
+ * Displays data of a given length according to selected options
+ *
+ * If a specific data type is provided in disp, then this is used. Otherwise
+ * we try to guess the data type / size from the contents.
+ *
+ * @param disp Display information / options
+ * @param data Data to display
+ * @param len Maximum length of buffer
+ * @return 0 if ok, -1 if data does not match format
+ */
+static int show_data(struct display_info *disp, const char *data, int len)
+{
+ int i, size;
+ const uint8_t *p = (const uint8_t *)data;
+ const char *s;
+ int value;
+ int is_string;
+ char fmt[3];
+
+ /* no data, don't print */
+ if (len == 0)
+ return 0;
+
+ is_string = (disp->type) == 's' ||
+ (!disp->type && util_is_printable_string(data, len));
+ if (is_string) {
+ if (data[len - 1] != '\0') {
+ fprintf(stderr, "Unterminated string\n");
+ return -1;
+ }
+ for (s = data; s - data < len; s += strlen(s) + 1) {
+ if (s != data)
+ printf(" ");
+ printf("%s", (const char *)s);
+ }
+ return 0;
+ }
+ size = disp->size;
+ if (size == -1)
+ size = (len % 4) == 0 ? 4 : 1;
+ else if (len % size) {
+ fprintf(stderr, "Property length must be a multiple of "
+ "selected data size\n");
+ return -1;
+ }
+ fmt[0] = '%';
+ fmt[1] = disp->type ? disp->type : 'd';
+ fmt[2] = '\0';
+ for (i = 0; i < len; i += size, p += size) {
+ if (i)
+ printf(" ");
+ value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
+ size == 2 ? (*p << 8) | p[1] : *p;
+ printf(fmt, value);
+ }
+ return 0;
+}
+
+/**
+ * Show the data for a given node (and perhaps property) according to the
+ * display option provided.
+ *
+ * @param blob FDT blob
+ * @param disp Display information / options
+ * @param node Node to display
+ * @param property Name of property to display, or NULL if none
+ * @return 0 if ok, -ve on error
+ */
+static int show_data_for_item(const void *blob, struct display_info *disp,
+ int node, const char *property)
+{
+ const void *value = NULL;
+ int len, err = 0;
+
+ value = fdt_getprop(blob, node, property, &len);
+ if (value) {
+ if (show_data(disp, value, len))
+ err = -1;
+ else
+ printf("\n");
+ } else {
+ report_error(property, len);
+ err = -1;
+ }
+ return err;
+}
+
+/**
+ * Run the main fdtget operation, given a filename and valid arguments
+ *
+ * @param disp Display information / options
+ * @param filename Filename of blob file
+ * @param arg List of arguments to process
+ * @param arg_count Number of arguments
+ * @param return 0 if ok, -ve on error
+ */
+static int do_fdtget(struct display_info *disp, const char *filename,
+ char **arg, int arg_count)
+{
+ char *blob;
+ int i, node;
+
+ blob = utilfdt_read(filename);
+ if (!blob)
+ return -1;
+
+ for (i = 0; i + 2 <= arg_count; i += 2) {
+ node = fdt_path_offset(blob, arg[0]);
+ if (node < 0) {
+ report_error(arg[0], node);
+ return -1;
+ }
+
+ if (show_data_for_item(blob, disp, node, arg[1]))
+ return -1;
+ }
+ return 0;
+}
+
+static const char *usage_msg =
+ "fdtget - read values from device tree\n"
+ "\n"
+ "Each value is printed on a new line.\n\n"
+ "Usage:\n"
+ " fdtget <options> <dt file> [<node> <property>]...\n"
+ "Options:\n"
+ "\t-t <type>\tType of data\n"
+ "\t-h\t\tPrint this help\n\n"
+ USAGE_TYPE_MSG;
+
+static void usage(const char *msg)
+{
+ if (msg)
+ fprintf(stderr, "Error: %s\n\n", msg);
+
+ fprintf(stderr, "%s", usage_msg);
+ exit(2);
+}
+
+int main(int argc, char *argv[])
+{
+ char *filename = NULL;
+ struct display_info disp;
+
+ /* set defaults */
+ memset(&disp, '\0', sizeof(disp));
+ disp.size = -1;
+ for (;;) {
+ int c = getopt(argc, argv, "ht:");
+ if (c == -1)
+ break;
+
+ switch (c) {
+ case 'h':
+ case '?':
+ usage(NULL);
+
+ case 't':
+ if (utilfdt_decode_type(optarg, &disp.type,
+ &disp.size))
+ usage("Invalid type string");
+ break;
+ }
+ }
+
+ if (optind < argc)
+ filename = argv[optind++];
+ if (!filename)
+ usage("Missing filename");
+
+ argv += optind;
+ argc -= optind;
+
+ /* Allow no arguments, and silently succeed */
+ if (!argc)
+ return 0;
+
+ /* Check for node, property arguments */
+ if (argc % 2)
+ usage("Must have an even number of arguments");
+
+ if (do_fdtget(&disp, filename, argv, argc))
+ return 1;
+ return 0;
+}
diff --git a/tests/fdtget-runtest.sh b/tests/fdtget-runtest.sh
new file mode 100755
index 0000000..f38184f
--- /dev/null
+++ b/tests/fdtget-runtest.sh
@@ -0,0 +1,35 @@
+#! /bin/sh
+
+. ./tests.sh
+
+LOG="tmp.log.$$"
+EXPECT="tmp.expect.$$"
+
+rm -f $TMPFILE $LOG
+
+expect="$1"
+echo "$expect" >$EXPECT
+shift
+
+verbose_run_log "$LOG" $VALGRIND "$DTGET" "$@"
+ret="$?"
+
+if [ "$ret" -ne 0 -a "$expect" = "ERR" ]; then
+ PASS
+fi
+
+if [ "$ret" -gt 127 ]; then
+ signame=$(kill -l $[ret - 128])
+ FAIL "Killed by SIG$signame"
+fi
+
+diff $EXPECT $LOG
+ret="$?"
+
+rm -f $LOG $EXPECT
+
+if [ "$ret" -eq 0 ]; then
+ PASS
+else
+ FAIL
+fi
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index e2c3046..a37a11d 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -83,6 +83,13 @@ asm_to_so_test () {
run_wrap_test asm_to_so "$@"
}
+run_fdtget_test () {
+ # run_fdtget_test name expected_output dtb_file args...
+ echo -n "$1: "
+ shift
+ base_run_test sh fdtget-runtest.sh "$@"
+}
+
tree1_tests () {
TREE=$1
@@ -391,6 +398,37 @@ dtbs_equal_tests () {
cmp_tests test_tree1.dtb $WRONG_TREE1
}
+fdtget_tests () {
+ file=label01.dtb
+ $DTC -O dtb -o $file ${file%.dtb}.dts 2>/dev/null
+
+ # run_fdtget_test <test-name> <expected-result> <args>...
+ run_fdtget_test "Simple string" "MyBoardName" $file / model
+ run_fdtget_test "Multiple string i" "77 121 66 111 \
+97 114 100 78 97 109 101 0 77 121 66 111 97 114 100 70 97 109 105 \
+108 121 78 97 109 101 0" $file / compatible
+ run_fdtget_test "Multiple string s" "MyBoardName MyBoardFamilyName" \
+ -t s $file / compatible
+ run_fdtget_test "Integer" "32768" $file /cpus/PowerPC,970 at 1 d-cache-size
+ run_fdtget_test "Integer hex" "8000" -tx $file \
+ /cpus/PowerPC,970 at 1 d-cache-size
+ run_fdtget_test "Integer list" "61 62 63 0" -tbx $file \
+ /randomnode tricky1
+ run_fdtget_test "Byte list short" "a b c d de ea ad be ef" -tbx \
+ $file /randomnode blob
+
+ # Here the property size is not a multiple of 4 bytes, so it should fail
+ run_fdtget_test "Integer list invalid" ERR -tlx \
+ $file /randomnode mixed
+ run_fdtget_test "Integer list halfword" "6162 6300 1234 0 a 0 b 0 c" -thx \
+ $file /randomnode mixed
+ run_fdtget_test "Integer list byte" \
+ "61 62 63 0 12 34 0 0 0 a 0 0 0 b 0 0 0 c" -thhx \
+ $file /randomnode mixed
+ run_fdtget_test "Missing property" ERR -ts \
+ $file /randomnode doctor-who
+}
+
utilfdt_tests () {
run_test utilfdt_test
}
@@ -410,7 +448,7 @@ while getopts "vt:m" ARG ; do
done
if [ -z "$TESTSETS" ]; then
- TESTSETS="libfdt utilfdt dtc dtbs_equal"
+ TESTSETS="libfdt utilfdt dtc dtbs_equal fdtget"
fi
# Make sure we don't have stale blobs lying around
@@ -430,6 +468,9 @@ for set in $TESTSETS; do
"dtbs_equal")
dtbs_equal_tests
;;
+ "fdtget")
+ fdtget_tests
+ ;;
esac
done
diff --git a/tests/tests.sh b/tests/tests.sh
index 30ffead..d9a0524 100644
--- a/tests/tests.sh
+++ b/tests/tests.sh
@@ -11,6 +11,7 @@ FAIL () {
}
DTC=../dtc
+DTGET=../fdtget
verbose_run () {
if [ -z "$QUIET_TEST" ]; then
diff --git a/util.h b/util.h
index 730918e..c8eb45d 100644
--- a/util.h
+++ b/util.h
@@ -140,4 +140,14 @@ int utilfdt_write_err(const char *filename, const void *blob);
*/
int utilfdt_decode_type(const char *fmt, int *type, int *size);
+/*
+ * This is a usage message fragment for the -t option. It is the format
+ * supported by utilfdt_decode_type.
+ */
+
+#define USAGE_TYPE_MSG \
+ "<type>\ts=string, i=int, u=unsigned, x=hex\n" \
+ "\tOptional modifier prefix:\n" \
+ "\t\thh or b=byte, h=2 byte, l=4 byte (default)\n";
+
#endif /* _UTIL_H */
--
1.7.3.1
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