Re: [PATCH v2 5/6] Add new fdtput utility to write values to fdt

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

On Wed, Sep 07, 2011 at 12:54:19PM -0700, Simon Glass wrote:
> This simple utility allows writing of values into a device tree from the
> command line. It aimes to be the opposite of fdtget.
> 
> What is it for:
> - Updating fdt values when a binary blob already exists
>    (even though source may be available it might be easier to use this
>     utility rather than sed, etc.)
> - Writing machine-specific fdt values within a build system
> 
> To use it, specify the fdt binary file on command line followed by the node
> and property to set. Then, provide a list of values to put into that
> property. Often there will be just one, but fdtput also supports arrays and
> string lists.
> 
> fdtput does not trit to guess the type of the property based on looking at
> the arguments. Instead it always assumed that an integer is provided. To
> indicate that you want to write a string, use -ts. You can also provide
> hex values with -tx.
> 
> The command line arguments are joined together into a single value. For
> strings, a nul terminator is placed between each string. To avoid this, pass
> the string as a single parameter.
> 
> Usage:
> 	fdtput <options> <dt file> <<node> <property> [<value>...]
> Options:
> 	-t [<type>][<format>]	Type of data
> 	-v		Verbose: display each value decoded from command line
> 	-h		Print this help
> 
> 	<type>		One character (s=string, i=int, u=unsigned, b=byte)
> 	<format>	Optional format character (x=hex)
> 
> To read from stdin and write to stdout, use - as the file. So you can do:
> 
> cat somefile.dtb | fdtput -ts - /node prop "My string value" > newfile.dtb
> 
> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
> Changes in v2:
> - Separate arguments for node and property
> - Remove limits on data size of property writting to fdt
> - Remove use of getopt_long()
> 
>  .gitignore      |    1 +
>  Makefile        |    6 ++
>  Makefile.fdtput |   12 +++
>  fdtput.c        |  217 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 236 insertions(+), 0 deletions(-)
>  create mode 100644 Makefile.fdtput
>  create mode 100644 fdtput.c
> 
> diff --git a/.gitignore b/.gitignore
> index 9f27f34..2c9a64e 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -11,3 +11,4 @@ lex.yy.c
>  /convert-dtsv0
>  /version_gen.h
>  /fdtget
> +/fdtput
> diff --git a/Makefile b/Makefile
> index 3d460d7..c6b57d7 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -107,11 +107,13 @@ include Makefile.convert-dtsv0
>  include Makefile.dtc
>  include Makefile.ftdump
>  include Makefile.fdtget
> +include Makefile.fdtput

Separate makefile fragments for the two utilities seems overkill.
Can't you just have one Makefile.utils or something.

>  
>  BIN += convert-dtsv0
>  BIN += dtc
>  BIN += ftdump
>  BIN += fdtget
> +BIN += fdtput
>  
>  SCRIPTS = dtdiff
>  
> @@ -123,6 +125,7 @@ ifneq ($(DEPTARGETS),)
>  -include $(CONVERT_OBJS:%.o=%.d)
>  -include $(FTDUMP_OBJS:%.o=%.d)
>  -include $(FDTGET_OBJS:%.o=%.d)
> +-include $(FDTPUT_OBJS:%.o=%.d)
>  endif
>  
>  
> @@ -185,6 +188,9 @@ ftdump:	$(FTDUMP_OBJS) $(LIBFDT_archive)
>  
>  fdtget:	$(FDTGET_OBJS) $(LIBFDT_archive)
>  
> +fdtput:	$(FDTPUT_OBJS) $(LIBFDT_archive)
> +
> +
>  #
>  # Testsuite rules
>  #
> diff --git a/Makefile.fdtput b/Makefile.fdtput
> new file mode 100644
> index 0000000..de1cfdf
> --- /dev/null
> +++ b/Makefile.fdtput
> @@ -0,0 +1,12 @@
> +#
> +# This is not a complete Makefile.
> +# Instead, it is designed to be easily embeddable
> +# into other systems of Makefiles.
> +#
> +
> +FDTPUT_SRCS = \
> +	fdtput.c \
> +	util.c \
> +	utilfdt.c
> +
> +FDTPUT_OBJS = $(FDTPUT_SRCS:%.c=%.o)
> diff --git a/fdtput.c b/fdtput.c
> new file mode 100644
> index 0000000..fd03d76
> --- /dev/null
> +++ b/fdtput.c
> @@ -0,0 +1,217 @@
> +/*
> + * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
> + * Distributed under the terms of the GNU General Public License v2
> + */
> +
> +#include <assert.h>
> +#include <ctype.h>
> +#include <getopt.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
> +#include <libfdt.h>
> +
> +#include "util.h"
> +#include "utilfdt.h"
> +
> +struct display_info {
> +	int type;		/* data type (s/i/u/b or 0 for default) */
> +	int format;		/* data format (x or 0 for default) */
> +	int verbose;		/* verbose output */
> +};
> +
> +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 disp		Display information / options
> + * @param arg		List of arguments from command line
> + * @param arg_count	Number of arguments (may be 0)
> + * @param valuep	Returns buffer containing value
> + * @param *value_len	Returns length of value encoded
> + */
> +static int encode_value(struct display_info *disp, char **arg, int arg_count,
> +			char **valuep, int *value_len)
> +{
> +	char *value = NULL;	/* holding area for value */
> +	int value_size = 0;	/* size of holding area */
> +	char *ptr;		/* pointer to current value position */
> +	int len;		/* length of this cell/string/byte */
> +	int ival;
> +	int upto;	/* the number of bytes we have written to buf */
> +
> +	upto = 0;
> +
> +	if (disp->verbose)
> +		fprintf(stderr, "Decoding value:\n");
> +	for (; arg_count > 0; arg++, arg_count--, upto += len) {
> +		/* assume integer unless told otherwise */
> +		if (disp->type == 's')
> +			len = strlen(*arg) + 1;
> +		else
> +			len = disp->type == 'b' ? 1 : 4;
> +
> +		/* enlarge our value buffer by a suitable margin if needed */
> +		if (upto + len > value_size) {
> +			value_size = (upto + len) + 500;
> +			value = realloc(value, value_size);
> +			if (!value) {
> +				fprintf(stderr, "Out of mmory: cannot alloc "
> +					"%d bytes\n", value_size);
> +				return -1;
> +			}
> +		}
> +
> +		ptr = value + upto;
> +		if (disp->type == 's') {
> +			memcpy(ptr, *arg, len);
> +			if (disp->verbose)
> +				fprintf(stderr, "\tstring: '%s'\n", ptr);
> +		} else {
> +			int *iptr = (int *)ptr;
> +
> +			sscanf(*arg, disp->format == 'x' ? "%x" : "%d", &ival);
> +			if (len == 4)
> +				*iptr = cpu_to_fdt32(ival);
> +			else
> +				*ptr = (uint8_t)ival;
> +			if (disp->verbose) {
> +				fprintf(stderr, "\t%s: %d\n",
> +					disp->type == 'b' ? "byte" : "int",
> +					ival);
> +			}
> +		}
> +	}
> +	*value_len = upto;
> +	*valuep = value;
> +	if (disp->verbose)
> +		fprintf(stderr, "Value size %d\n", upto);
> +	return 0;
> +}
> +
> +static int store_key_value(void *blob, const char *node_name,
> +		const char *property, const char *buf, int len)
> +{
> +	int node;
> +	int err;
> +
> +	node = fdt_path_offset(blob, node_name);
> +	if (node < 0) {
> +		report_error(node_name, node);
> +		return -1;
> +	}
> +
> +	err = fdt_setprop(blob, node, property, buf, len);
> +	if (err) {
> +		report_error(property, err);
> +		return -1;
> +	}
> +	return 0;
> +}
> +
> +static int do_fdtput(struct display_info *disp, const char *filename,
> +		    char **arg, int arg_count)
> +{
> +	char *value;
> +	char *blob;
> +	int len, ret = 0;
> +
> +	blob = util_read_fdt(filename);
> +	if (!blob)
> +		return -1;
> +
> +	/* convert the arguments into a single binary value, then store */
> +	assert(arg_count >= 2);
> +	if (encode_value(disp, arg + 2, arg_count - 2, &value, &len) ||
> +		store_key_value(blob, *arg, arg[1], value, len))
> +		ret = -1;
> +
> +	if (!ret)
> +		ret = util_write_fdt(blob, filename);
> +
> +	free(blob);
> +	return ret;
> +}
> +
> +static const char *usage_msg =
> +	"fdtput - write a property value to a device tree\n"
> +	"\n"
> +	"The command line arguments are joined together into a single value.\n"
> +	"\n"
> +	"Usage:\n"
> +	"	fdtput <options> <dt file> <<node> <property> [<value>...]\n"
> +	"Options:\n"
> +	"\t-t [<type>][<format>]\tType of data\n"
> +	"\t-v\t\tVerbose: display each value decoded from command line\n"
> +	"\t-h\t\tPrint this help\n\n"
> +	"\t<type>\t\tOne character (s=string, i=int, u=unsigned, b=byte)\n"
> +	"\t<format>\tOptional format character (x=hex)\n";
> +
> +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[])
> +{
> +	struct display_info disp;
> +	char *filename = NULL;
> +
> +	memset(&disp, '\0', sizeof(disp));
> +	for (;;) {
> +		int c = getopt(argc, argv, "ht:v");
> +		if (c == -1)
> +			break;
> +
> +		/*
> +		 * TODO: add options to:
> +		 * - delete property
> +		 * - delete node (optionally recursively)
> +		 * - rename node
> +		 * - pack fdt before writing
> +		 * - set amount of free space when writing
> +		 * - expand fdt if value doesn't fit
> +		 */
> +		switch (c) {
> +		case 'h':
> +		case '?':
> +			usage("");
> +
> +		case 't':
> +			if (utilfdt_decode_type(optarg, &disp.type,
> +					&disp.format))
> +				usage("Invalid type string");
> +			break;
> +
> +		case 'v':
> +			disp.verbose = 1;
> +			break;
> +		}
> +	}
> +
> +	if (optind < argc)
> +		filename = argv[optind++];
> +	if (!filename)
> +		usage("Missing filename");
> +
> +	argv += optind;
> +	argc -= optind;
> +
> +	if (argc < 1)
> +		usage("Missing node");
> +	if (argc < 2)
> +		usage("Missing property");
> +
> +	if (do_fdtput(&disp, filename, argv, argc))
> +		return 1;
> +	return 0;
> +}

-- 
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