[PATCH 2/9] Add dtget utility to read property values from device tree
Grant Likely
grant.likely at secretlab.ca
Thu Jul 7 04:41:13 EST 2011
On Tue, Jul 05, 2011 at 12:02:50PM -0700, Simon Glass wrote:
> This simply utility makes it easy for scripts to read values from the device
> tree.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
Looks okay to me.
g.
> ---
> .gitignore | 1 +
> Makefile | 7 ++
> Makefile.dtget | 13 ++++
> dtget.c | 207 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 228 insertions(+), 0 deletions(-)
> create mode 100644 Makefile.dtget
> create mode 100644 dtget.c
>
> diff --git a/.gitignore b/.gitignore
> index ae7a46a..cde4fa5 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -10,3 +10,4 @@ lex.yy.c
> /ftdump
> /convert-dtsv0
> /version_gen.h
> +/dtget
> diff --git a/Makefile b/Makefile
> index 22f79a0..3401a65 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -106,10 +106,12 @@ endef
> include Makefile.convert-dtsv0
> include Makefile.dtc
> include Makefile.ftdump
> +include Makefile.dtget
>
> BIN += convert-dtsv0
> BIN += dtc
> BIN += ftdump
> +BIN += dtget
>
> SCRIPTS = dtdiff
>
> @@ -120,6 +122,7 @@ ifneq ($(DEPTARGETS),)
> -include $(DTC_OBJS:%.o=%.d)
> -include $(CONVERT_OBJS:%.o=%.d)
> -include $(FTDUMP_OBJS:%.o=%.d)
> +-include $(DTGET_OBJS:%.o=%.d)
> endif
>
>
> @@ -180,6 +183,10 @@ convert-dtsv0: $(CONVERT_OBJS)
>
> ftdump: $(FTDUMP_OBJS)
>
> +dtget: $(DTGET_OBJS) $(LIBFDT_archive)
> + $(VECHO) LD $@
> + $(LINK.c) -o $@ $^
> +
>
> #
> # Testsuite rules
> diff --git a/Makefile.dtget b/Makefile.dtget
> new file mode 100644
> index 0000000..edda499
> --- /dev/null
> +++ b/Makefile.dtget
> @@ -0,0 +1,13 @@
> +#
> +# This is not a complete Makefile.
> +# Instead, it is designed to be easily embeddable
> +# into other systems of Makefiles.
> +#
> +
> +DTGET_SRCS = \
> + dtget.c \
> + util.c
> +
> +DTGET_GEN_SRCS =
> +
> +DTGET_OBJS = $(DTGET_SRCS:%.c=%.o) $(DTGET_GEN_SRCS:%.c=%.o)
> diff --git a/dtget.c b/dtget.c
> new file mode 100644
> index 0000000..0ee577c
> --- /dev/null
> +++ b/dtget.c
> @@ -0,0 +1,207 @@
> +/*
> + * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
> + * Distributed under the terms of the GNU General Public License v2
> + *
> + * is_printable_string from ftdump.c
> + * Contributed by Pantelis Antoniou <pantelis.antoniou AT gmail.com>
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <getopt.h>
> +#include <ctype.h>
> +
> +#include <libfdt.h>
> +
> +#include "util.h"
> +
> +#define FTDUMP_BUF_SIZE 65536
> +
> +static void report_error(const char *where, int err)
> +{
> + fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
> +}
> +
> +static void show_data(const char *format, int type, const char *data, int len)
> +{
> + int i, size;
> + const char *p = data, *s;
> + int value;
> + int is_string;
> +
> + /* no data, don't print */
> + if (len == 0)
> + return;
> +
> + is_string = type == 's' ||
> + (!type && util_is_printable_string(data, len));
> + if (is_string) {
> + for (s = data; s - data < len; s += strlen(s) + 1) {
> + if (s != data)
> + printf(" ");
> + printf(format ? format : "%s", (const char *)s);
> + }
> + return;
> + }
> + if (type == 'i')
> + size = 4;
> + else if (type == 'b')
> + size = 1;
> + else
> + size = len % 4 == 0 ? 4 : 1;
> + for (i = 0; i < len; i += size, p += size) {
> + if (i)
> + printf(" ");
> + value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
> + *(const unsigned char *)p;
> + printf(format ? format : "%d", value);
> + }
> +}
> +
> +static int show_data_for_key(const void *blob, const char *format, int type,
> + char *key)
> +{
> + char *ptr, *prop;
> + int node, guess_node = 0;
> + const void *value;
> + int len;
> +
> + /* First extract the property from the end */
> + ptr = strrchr(key, '/');
> + if (!ptr) {
> + fprintf(stderr, "No node found in key '%s'\n", key);
> + return 5;
> + }
> +
> + if (ptr == key) {
> + guess_node = fdt_path_offset(blob, key);
> + node = fdt_path_offset(blob, "/");
> + } else {
> + *ptr = '\0';
> + node = fdt_path_offset(blob, key);
> + *ptr = '/';
> + }
> + if (node < 0) {
> + report_error(key, node);
> + return 7;
> + }
> + prop = ptr + 1;
> + value = fdt_getprop(blob, node, prop, &len);
> + if (!value) {
> + report_error(prop, len);
> + if (guess_node)
> + fprintf(stderr, "(Node %s exists but you didn't "
> + "specify a property to print)\n", key);
> + return 8;
> + }
> + show_data(format, type, value, len);
> + printf("\n");
> + return 0;
> +}
> +
> +static int do_dtget(const char *filename, const char *format, int type,
> + char **key, int key_count)
> +{
> + FILE *fp;
> + char *buf;
> + size_t size;
> + int i, ret;
> +
> + if (strcmp(filename, "-") == 0) {
> + fp = stdin;
> + } else {
> + fp = fopen(filename, "rb");
> + if (fp == NULL) {
> + fprintf(stderr, "unable to open %s\n", filename);
> + return 10;
> + }
> + }
> +
> + buf = malloc(FTDUMP_BUF_SIZE);
> + if (!buf) {
> + fprintf(stderr, "Couldn't allocate %d byte buffer\n",
> + FTDUMP_BUF_SIZE);
> + return 10;
> + }
> +
> + size = fread(buf, 1, FTDUMP_BUF_SIZE, fp);
> + if (!feof(fp)) {
> + fprintf(stderr, "file too large (maximum is %d bytes)\n",
> + FTDUMP_BUF_SIZE);
> + return 10;
> + }
> + if (ferror(fp)) {
> + fprintf(stderr, "file read error\n");
> + return 10;
> + }
> + for (i = 0; i < key_count; i++) {
> + ret = show_data_for_key(buf, format, type, key[i]);
> + if (ret)
> + return ret;
> + }
> + return 0;
> +}
> +
> +static void usage(const char *msg)
> +{
> + if (msg)
> + fprintf(stderr, "Error: %s\n\n", msg);
> + fprintf(stderr, "dtget - read values from device tree\n\n");
> + fprintf(stderr, "Usage: dtget <options> <dt file> <key>...\n");
> + fprintf(stderr, "Options:\n");
> + fprintf(stderr, "\t-f, --format <fmt>\tPrintf format string to use "
> + "for value\n");
> + fprintf(stderr, "\t-t, --type <typechar>\tForce type to be string "
> + "(s), int(i) or byte(b)\n");
> + fprintf(stderr, "\t-h, --help\t\tPrint this help\n\n");
> + fprintf(stderr, "\t<key> is <node>/<property>, for example "
> + "/lcd/width for the width\n");
> + fprintf(stderr, "\tproperty in the LCD node\n");
> + exit(2);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + int c;
> + int ret;
> + char *format = NULL;
> + int type = 0;
> + char *filename = NULL;
> + static struct option long_options[] = {
> + {"format", 1, 0, 'f'},
> + {"help", 1, 0, 'h'},
> + {"type", 1, 0, 't'},
> + {0, 0, 0, 0}
> + };
> +
> + for (;;) {
> + c = getopt_long(argc, argv, "f:ht:", long_options, NULL);
> + if (c == -1)
> + break;
> +
> + switch (c) {
> + case 'h':
> + case '?':
> + usage("");
> +
> + case 'f':
> + format = optarg;
> + break;
> +
> + case 't':
> + type = *optarg;
> + break;
> + }
> + }
> +
> + if (optind < argc)
> + filename = argv[optind++];
> + if (!filename)
> + usage("Missing filename");
> + if (optind == argc)
> + usage("Missing key(s)");
> +
> + ret = do_dtget(filename, format, type, argv + optind, argc - optind);
> + return ret;
> +}
> --
> 1.7.3.1
>
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