scripts/dtc/fdtget.c

   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
  37 enum 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 */
  44 struct 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
  51 static 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  */
  67 static 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  */
 122 static 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  */
 150 static 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  */
 206 static 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  */
 250 static 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
 280 static 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
 296 static 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
 305 int 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 }