On Wed, Sep 07, 2011 at 12:54:17PM -0700, Simon Glass wrote: > 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>][<format>] Type of data > -h Print this help > > <type> One character (s=string, i=int, u=unsigned, b=byte) > <format> Optional format character (x=hex)
It is not terribly clear how these are combined. Is there any way to make these more closely resemble printf() style format specifiers? > > Signed-off-by: Simon Glass <[email protected]> > --- > 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() > > .gitignore | 1 + > Makefile | 4 + > Makefile.fdtget | 12 +++ > fdtget.c | 200 > +++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 217 insertions(+), 0 deletions(-) > create mode 100644 Makefile.fdtget > create mode 100644 fdtget.c > > 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 0baada5..3d460d7 100644 > --- a/Makefile > +++ b/Makefile > @@ -106,10 +106,12 @@ endef > include Makefile.convert-dtsv0 > include Makefile.dtc > include Makefile.ftdump > +include Makefile.fdtget > > BIN += convert-dtsv0 > BIN += dtc > BIN += ftdump > +BIN += fdtget > > SCRIPTS = dtdiff > > @@ -120,6 +122,7 @@ 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 +183,7 @@ convert-dtsv0: $(CONVERT_OBJS) > > ftdump: $(FTDUMP_OBJS) $(LIBFDT_archive) > > +fdtget: $(FDTGET_OBJS) $(LIBFDT_archive) > > # > # Testsuite rules > diff --git a/Makefile.fdtget b/Makefile.fdtget > new file mode 100644 > index 0000000..c1ab041 > --- /dev/null > +++ b/Makefile.fdtget > @@ -0,0 +1,12 @@ > +# > +# This is not a complete Makefile. > +# Instead, it is designed to be easily embeddable > +# into other systems of Makefiles. > +# > + > +FDTGET_SRCS = \ > + fdtget.c \ > + util.c \ > + utilfdt.c > + > +FDTGET_OBJS = $(FDTGET_SRCS:%.c=%.o) > diff --git a/fdtget.c b/fdtget.c > new file mode 100644 > index 0000000..4a94e99 > --- /dev/null > +++ b/fdtget.c > @@ -0,0 +1,200 @@ > +/* > + * 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" > + > +/* Holds information which controls our output and options */ > +struct display_info { > + int type; /* data type (s/i/u/b or 0 for default) */ > + int format; /* data format (x or 0 for default) */ > +}; > + > +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 > + */ > +static void show_data(struct display_info *disp, 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 = (disp->type) == 's' || > + (!disp->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("%s", (const char *)s); > + } > + return; > + } > + if (disp->type == 'i' || disp->type == 'u') > + size = 4; > + else if (disp->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(disp->format == 'x' ? "%x" : "%d", value); > + } > +} > + > +/** > + * Show the data for a given node (and perhaps property) according to the > + * display option provided. "and perhaps property"? AFAICT this will SEGV if property is NULL. > + * @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) { > + show_data(disp, value, len); > + 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 = util_read_fdt(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>][<format>]\tType of data\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[]) > +{ > + char *filename = NULL; > + struct display_info disp; > + > + memset(&disp, '\0', sizeof(disp)); > + for (;;) { > + int c = getopt(argc, argv, "ht:"); > + if (c == -1) > + break; > + > + switch (c) { > + case 'h': > + case '?': > + usage(""); > + > + case 't': > + if (utilfdt_decode_type(optarg, &disp.type, > + &disp.format)) > + 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; > +} -- 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 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
