Re: [PATCH 6/9] Add new dtput utility to write values to fdt

[Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>]

On Tue, Jul 05, 2011 at 12:02:54PM -0700, Simon Glass wrote:
> This simple utility allows writing of values into a device tree from the
> command line.
> 
> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
>  Makefile       |    7 ++
>  Makefile.dtput |   14 ++++
>  dtput.c        |  199 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 220 insertions(+), 0 deletions(-)
>  create mode 100644 Makefile.dtput
>  create mode 100644 dtput.c
> 
> diff --git a/Makefile b/Makefile
> index 3401a65..e216006 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -107,11 +107,13 @@ include Makefile.convert-dtsv0
>  include Makefile.dtc
>  include Makefile.ftdump
>  include Makefile.dtget
> +include Makefile.dtput
>  
>  BIN += convert-dtsv0
>  BIN += dtc
>  BIN += ftdump
>  BIN += dtget
> +BIN += dtput
>  
>  SCRIPTS = dtdiff
>  
> @@ -123,6 +125,7 @@ ifneq ($(DEPTARGETS),)
>  -include $(CONVERT_OBJS:%.o=%.d)
>  -include $(FTDUMP_OBJS:%.o=%.d)
>  -include $(DTGET_OBJS:%.o=%.d)
> +-include $(DTPUT_OBJS:%.o=%.d)
>  endif
>  
>  
> @@ -187,6 +190,10 @@ dtget:	$(DTGET_OBJS) $(LIBFDT_archive)
>  	$(VECHO) LD $@
>  	$(LINK.c) -o $@ $^
>  
> +dtput:	$(DTPUT_OBJS) $(LIBFDT_archive)
> +	$(VECHO) LD $@
> +	$(LINK.c) -o $@ $^
> +
>  
>  #
>  # Testsuite rules
> diff --git a/Makefile.dtput b/Makefile.dtput
> new file mode 100644
> index 0000000..92eb054
> --- /dev/null
> +++ b/Makefile.dtput
> @@ -0,0 +1,14 @@
> +#
> +# This is not a complete Makefile.
> +# Instead, it is designed to be easily embeddable
> +# into other systems of Makefiles.
> +#
> +
> +DTPUT_SRCS = \
> +	dtput.c \
> +	util.c \
> +	utilfdt.c
> +
> +DTPUT_GEN_SRCS =
> +
> +DTPUT_OBJS = $(DTPUT_SRCS:%.c=%.o) $(DTPUT_GEN_SRCS:%.c=%.o)
> diff --git a/dtput.c b/dtput.c
> new file mode 100644
> index 0000000..48e3c75
> --- /dev/null
> +++ b/dtput.c
> @@ -0,0 +1,199 @@
> +/*
> + * 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 <ctype.h>
> +#include <getopt.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
> +#include <libfdt.h>
> +
> +#include "util.h"
> +#include "utilfdt.h"
> +
> +int verbose;		/* verbose output */
> +
> +enum {
> +	MAX_VALUE_SIZE = 1024
> +};
> +
> +static void report_error(const char *where, int err)
> +{
> +	fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
> +}
> +
> +/**
> + * Encode a series of arguments in a property value.
> + *
> + * @param arg	List of arguments from command line
> + * @param arg_count	Number of arguments (may be 0)
> + * @param format	sscanf() format string to use, NULL for default
> + * @param type		Value type (s=string, i=int, b=byte)
> + * @param buf		Buffer to place value into
> + * @param malen		Maximum length of buffer
> + * @param *value_len	Returns length of value encoded
> + */
> +static int encode_value(char **arg, int arg_count, const char *format,
> +		int type, char *buf, int maxlen, int *value_len)
> +{
> +	char value[MAX_VALUE_SIZE];	/* holding area for values */
> +	int len;	/* length of this cell/string/byte */
> +	int *iptr = (int *)value;
> +	int ival;
> +	int upto;	/* the number of bytes we have written to buf */
> +
> +	upto = 0;
> +
> +	if (verbose)
> +		fprintf(stderr, "Decoding value:\n");
> +	for (; arg_count > 0; arg++, arg_count--, upto += len) {
> +		/* assume integer unless told otherwise */
> +		if (type == 's') {
> +			sscanf(*arg, format ? format : "%s", value);
> +			len = strlen(value) + 1;
> +			if (verbose)
> +				fprintf(stderr, "\tstring: '%s'\n", value);
> +		} else {
> +			len = type == 'b' ? 1 : 4;
> +			sscanf(*arg, format ? format : "%d", &ival);
> +			if (len == 4)
> +				*iptr = cpu_to_fdt32(ival);
> +			else
> +				*value = (uint8_t)ival;
> +			if (verbose) {
> +				fprintf(stderr, "\t%s: %d\n",
> +					type == 'b' ? "byte" : "int", ival);
> +			}
> +		}
> +		if (upto + len > maxlen)
> +			return 8;
> +		memcpy(buf + upto, value, len);
> +	}
> +	*value_len = upto;
> +	if (verbose)
> +		fprintf(stderr, "Value size %d\n", upto);
> +	return 0;
> +}
> +
> +static int store_key_value(void *blob, char *key, const char *buf, int len)
> +{
> +	char *prop;
> +	int node, guess_node;
> +	int err;
> +
> +	node = util_decode_key(blob, key, &prop, &guess_node);
> +	if (node < 0) {
> +		report_error(key, node);
> +		return 7;
> +	}
> +
> +	err = fdt_setprop(blob, node, prop, buf, len);
> +	if (err) {
> +		report_error(prop, len);
> +		if (guess_node)
> +			fprintf(stderr, "(Node %s exists but you didn't "
> +				"specify a property to set)\n", key);
> +		return 8;
> +	}
> +	return 0;
> +}
> +
> +static int do_dtput(const char *filename, const char *format, int type,
> +		    char **arg, int arg_count)
> +{
> +	char *blob;
> +	int ret, len;
> +	char buf[MAX_VALUE_SIZE];
> +
> +	blob = util_read_fdt(filename);
> +	if (!blob)
> +		return 10;
> +
> +	if (arg_count > 0) {
> +		/* convert the value into binary */
> +		ret = encode_value(arg + 1, arg_count - 1, format, type, buf,
> +				MAX_VALUE_SIZE, &len);
> +		if (ret)
> +			return 8;
> +
> +		ret = store_key_value(blob, *arg, buf, len);
> +		if (ret)
> +			return ret;
> +	}
> +	return util_write_fdt(blob, filename);
> +}
> +
> +static void usage(const char *msg)
> +{
> +	if (msg)
> +		fprintf(stderr, "Error: %s\n\n", msg);
> +	fprintf(stderr, "dtput - write a property value to a device tree\n\n");
> +	fprintf(stderr, "Usage: dtput <options> <dt file> <key> "
> +		"[<value>...]\n");
> +	fprintf(stderr, "Options:\n");
> +	fprintf(stderr, "\t-f, --format <fmt>\tScanf format string to use "
> +		"for value\n");
> +	fprintf(stderr, "\t-t, --type <typechar>\tForce type to be string "
> +		"(s), byte(b) or int(i)\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");

Can you make this text a single string and only call fprintf once?  It
will be easier to reqd that way.

It would be useful to have a mode for removing or renaming properties/nodes.

> +	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'},
> +		{"verbose", 1, 0, 'v'},
> +		{0, 0, 0, 0}
> +	};
> +
> +	for (;;) {
> +		c = getopt_long(argc, argv, "f:ht:v", long_options, NULL);
> +		if (c == -1)
> +			break;
> +
> +		switch (c) {
> +		case 'h':
> +		case '?':
> +			usage(NULL);
> +
> +		case 'f':
> +			format = optarg;
> +			break;
> +
> +		case 't':
> +			type = *optarg;
> +			break;
> +
> +		case 'v':
> +			verbose = 1;
> +			break;
> +		}
> +	}
> +
> +	if (optind < argc)
> +		filename = argv[optind++];
> +	if (!filename)
> +		usage("Missing filename");
> +	if (optind == argc)
> +		usage("Missing key(s)");
> +
> +	ret = do_dtput(filename, format, type, argv + optind, argc - optind);
> +	return ret;
> +}
> -- 
> 1.7.3.1
>