linux/scripts/dtc/fdtget.c
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   1/*
   2 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
   3 *
   4 * Portions from U-Boot cmd_fdt.c (C) Copyright 2007
   5 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
   6 * Based on code written by:
   7 *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
   8 *   Matthew McClintock <msm@freescale.com>
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU General Public License as
  12 * published by the Free Software Foundation; either version 2 of
  13 * the License, or (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23 * MA 02111-1307 USA
  24 */
  25
  26#include <assert.h>
  27#include <ctype.h>
  28#include <getopt.h>
  29#include <stdio.h>
  30#include <stdlib.h>
  31#include <string.h>
  32
  33#include <libfdt.h>
  34
  35#include "util.h"
  36
  37enum display_mode {
  38        MODE_SHOW_VALUE,        /* show values for node properties */
  39        MODE_LIST_PROPS,        /* list the properties for a node */
  40        MODE_LIST_SUBNODES,     /* list the subnodes of a node */
  41};
  42
  43/* Holds information which controls our output and options */
  44struct display_info {
  45        int type;               /* data type (s/i/u/x or 0 for default) */
  46        int size;               /* data size (1/2/4) */
  47        enum display_mode mode; /* display mode that we are using */
  48        const char *default_val; /* default value if node/property not found */
  49};
  50
  51static void report_error(const char *where, int err)
  52{
  53        fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
  54}
  55
  56/**
  57 * Displays data of a given length according to selected options
  58 *
  59 * If a specific data type is provided in disp, then this is used. Otherwise
  60 * we try to guess the data type / size from the contents.
  61 *
  62 * @param disp          Display information / options
  63 * @param data          Data to display
  64 * @param len           Maximum length of buffer
  65 * @return 0 if ok, -1 if data does not match format
  66 */
  67static int show_data(struct display_info *disp, const char *data, int len)
  68{
  69        int i, size;
  70        const uint8_t *p = (const uint8_t *)data;
  71        const char *s;
  72        int value;
  73        int is_string;
  74        char fmt[3];
  75
  76        /* no data, don't print */
  77        if (len == 0)
  78                return 0;
  79
  80        is_string = (disp->type) == 's' ||
  81                (!disp->type && util_is_printable_string(data, len));
  82        if (is_string) {
  83                if (data[len - 1] != '\0') {
  84                        fprintf(stderr, "Unterminated string\n");
  85                        return -1;
  86                }
  87                for (s = data; s - data < len; s += strlen(s) + 1) {
  88                        if (s != data)
  89                                printf(" ");
  90                        printf("%s", (const char *)s);
  91                }
  92                return 0;
  93        }
  94        size = disp->size;
  95        if (size == -1) {
  96                size = (len % 4) == 0 ? 4 : 1;
  97        } else if (len % size) {
  98                fprintf(stderr, "Property length must be a multiple of "
  99                                "selected data size\n");
 100                return -1;
 101        }
 102        fmt[0] = '%';
 103        fmt[1] = disp->type ? disp->type : 'd';
 104        fmt[2] = '\0';
 105        for (i = 0; i < len; i += size, p += size) {
 106                if (i)
 107                        printf(" ");
 108                value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
 109                        size == 2 ? (*p << 8) | p[1] : *p;
 110                printf(fmt, value);
 111        }
 112        return 0;
 113}
 114
 115/**
 116 * List all properties in a node, one per line.
 117 *
 118 * @param blob          FDT blob
 119 * @param node          Node to display
 120 * @return 0 if ok, or FDT_ERR... if not.
 121 */
 122static int list_properties(const void *blob, int node)
 123{
 124        const struct fdt_property *data;
 125        const char *name;
 126        int prop;
 127
 128        prop = fdt_first_property_offset(blob, node);
 129        do {
 130                /* Stop silently when there are no more properties */
 131                if (prop < 0)
 132                        return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
 133                data = fdt_get_property_by_offset(blob, prop, NULL);
 134                name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
 135                if (name)
 136                        puts(name);
 137                prop = fdt_next_property_offset(blob, prop);
 138        } while (1);
 139}
 140
 141#define MAX_LEVEL       32              /* how deeply nested we will go */
 142
 143/**
 144 * List all subnodes in a node, one per line
 145 *
 146 * @param blob          FDT blob
 147 * @param node          Node to display
 148 * @return 0 if ok, or FDT_ERR... if not.
 149 */
 150static int list_subnodes(const void *blob, int node)
 151{
 152        int nextoffset;         /* next node offset from libfdt */
 153        uint32_t tag;           /* current tag */
 154        int level = 0;          /* keep track of nesting level */
 155        const char *pathp;
 156        int depth = 1;          /* the assumed depth of this node */
 157
 158        while (level >= 0) {
 159                tag = fdt_next_tag(blob, node, &nextoffset);
 160                switch (tag) {
 161                case FDT_BEGIN_NODE:
 162                        pathp = fdt_get_name(blob, node, NULL);
 163                        if (level <= depth) {
 164                                if (pathp == NULL)
 165                                        pathp = "/* NULL pointer error */";
 166                                if (*pathp == '\0')
 167                                        pathp = "/";    /* root is nameless */
 168                                if (level == 1)
 169                                        puts(pathp);
 170                        }
 171                        level++;
 172                        if (level >= MAX_LEVEL) {
 173                                printf("Nested too deep, aborting.\n");
 174                                return 1;
 175                        }
 176                        break;
 177                case FDT_END_NODE:
 178                        level--;
 179                        if (level == 0)
 180                                level = -1;             /* exit the loop */
 181                        break;
 182                case FDT_END:
 183                        return 1;
 184                case FDT_PROP:
 185                        break;
 186                default:
 187                        if (level <= depth)
 188                                printf("Unknown tag 0x%08X\n", tag);
 189                        return 1;
 190                }
 191                node = nextoffset;
 192        }
 193        return 0;
 194}
 195
 196/**
 197 * Show the data for a given node (and perhaps property) according to the
 198 * display option provided.
 199 *
 200 * @param blob          FDT blob
 201 * @param disp          Display information / options
 202 * @param node          Node to display
 203 * @param property      Name of property to display, or NULL if none
 204 * @return 0 if ok, -ve on error
 205 */
 206static int show_data_for_item(const void *blob, struct display_info *disp,
 207                int node, const char *property)
 208{
 209        const void *value = NULL;
 210        int len, err = 0;
 211
 212        switch (disp->mode) {
 213        case MODE_LIST_PROPS:
 214                err = list_properties(blob, node);
 215                break;
 216
 217        case MODE_LIST_SUBNODES:
 218                err = list_subnodes(blob, node);
 219                break;
 220
 221        default:
 222                assert(property);
 223                value = fdt_getprop(blob, node, property, &len);
 224                if (value) {
 225                        if (show_data(disp, value, len))
 226                                err = -1;
 227                        else
 228                                printf("\n");
 229                } else if (disp->default_val) {
 230                        puts(disp->default_val);
 231                } else {
 232                        report_error(property, len);
 233                        err = -1;
 234                }
 235                break;
 236        }
 237
 238        return err;
 239}
 240
 241/**
 242 * Run the main fdtget operation, given a filename and valid arguments
 243 *
 244 * @param disp          Display information / options
 245 * @param filename      Filename of blob file
 246 * @param arg           List of arguments to process
 247 * @param arg_count     Number of arguments
 248 * @param return 0 if ok, -ve on error
 249 */
 250static int do_fdtget(struct display_info *disp, const char *filename,
 251                     char **arg, int arg_count, int args_per_step)
 252{
 253        char *blob;
 254        const char *prop;
 255        int i, node;
 256
 257        blob = utilfdt_read(filename);
 258        if (!blob)
 259                return -1;
 260
 261        for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
 262                node = fdt_path_offset(blob, arg[i]);
 263                if (node < 0) {
 264                        if (disp->default_val) {
 265                                puts(disp->default_val);
 266                                continue;
 267                        } else {
 268                                report_error(arg[i], node);
 269                                return -1;
 270                        }
 271                }
 272                prop = args_per_step == 1 ? NULL : arg[i + 1];
 273
 274                if (show_data_for_item(blob, disp, node, prop))
 275                        return -1;
 276        }
 277        return 0;
 278}
 279
 280static const char *usage_msg =
 281        "fdtget - read values from device tree\n"
 282        "\n"
 283        "Each value is printed on a new line.\n\n"
 284        "Usage:\n"
 285        "       fdtget <options> <dt file> [<node> <property>]...\n"
 286        "       fdtget -p <options> <dt file> [<node> ]...\n"
 287        "Options:\n"
 288        "\t-t <type>\tType of data\n"
 289        "\t-p\t\tList properties for each node\n"
 290        "\t-l\t\tList subnodes for each node\n"
 291        "\t-d\t\tDefault value to display when the property is "
 292                        "missing\n"
 293        "\t-h\t\tPrint this help\n\n"
 294        USAGE_TYPE_MSG;
 295
 296static void usage(const char *msg)
 297{
 298        if (msg)
 299                fprintf(stderr, "Error: %s\n\n", msg);
 300
 301        fprintf(stderr, "%s", usage_msg);
 302        exit(2);
 303}
 304
 305int main(int argc, char *argv[])
 306{
 307        char *filename = NULL;
 308        struct display_info disp;
 309        int args_per_step = 2;
 310
 311        /* set defaults */
 312        memset(&disp, '\0', sizeof(disp));
 313        disp.size = -1;
 314        disp.mode = MODE_SHOW_VALUE;
 315        for (;;) {
 316                int c = getopt(argc, argv, "d:hlpt:");
 317                if (c == -1)
 318                        break;
 319
 320                switch (c) {
 321                case 'h':
 322                case '?':
 323                        usage(NULL);
 324
 325                case 't':
 326                        if (utilfdt_decode_type(optarg, &disp.type,
 327                                        &disp.size))
 328                                usage("Invalid type string");
 329                        break;
 330
 331                case 'p':
 332                        disp.mode = MODE_LIST_PROPS;
 333                        args_per_step = 1;
 334                        break;
 335
 336                case 'l':
 337                        disp.mode = MODE_LIST_SUBNODES;
 338                        args_per_step = 1;
 339                        break;
 340
 341                case 'd':
 342                        disp.default_val = optarg;
 343                        break;
 344                }
 345        }
 346
 347        if (optind < argc)
 348                filename = argv[optind++];
 349        if (!filename)
 350                usage("Missing filename");
 351
 352        argv += optind;
 353        argc -= optind;
 354
 355        /* Allow no arguments, and silently succeed */
 356        if (!argc)
 357                return 0;
 358
 359        /* Check for node, property arguments */
 360        if (args_per_step == 2 && (argc % 2))
 361                usage("Must have an even number of arguments");
 362
 363        if (do_fdtget(&disp, filename, argv, argc, args_per_step))
 364                return 1;
 365        return 0;
 366}
 367
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