[PATCH v2 5/6] Add new fdtput utility to write values to fdt
David Gibson
david at gibson.dropbear.id.au
Thu Sep 8 15:32:09 EST 2011
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 at chromium.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
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