scripts/dtc/fdtget.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
   4  *
   5  * Portions from U-Boot cmd_fdt.c (C) Copyright 2007
   6  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
   7  * Based on code written by:
   8  *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
   9  *   Matthew McClintock <msm@freescale.com>
  10  */
  11
  12 #include <assert.h>
  13 #include <ctype.h>
  14 #include <getopt.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18
  19 #include <libfdt.h>
  20
  21 #include "util.h"
  22
  23 enum display_mode {
  24         MODE_SHOW_VALUE,        /* show values for node properties */
  25         MODE_LIST_PROPS,        /* list the properties for a node */
  26         MODE_LIST_SUBNODES,     /* list the subnodes of a node */
  27 };
  28
  29 /* Holds information which controls our output and options */
  30 struct display_info {
  31         int type;               /* data type (s/i/u/x or 0 for default) */
  32         int size;               /* data size (1/2/4) */
  33         enum display_mode mode; /* display mode that we are using */
  34         const char *default_val; /* default value if node/property not found */
  35 };
  36
  37 static void report_error(const char *where, int err)
  38 {
  39         fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
  40 }
  41
  42 /**
  43  * Displays data of a given length according to selected options
  44  *
  45  * If a specific data type is provided in disp, then this is used. Otherwise
  46  * we try to guess the data type / size from the contents.
  47  *
  48  * @param disp          Display information / options
  49  * @param data          Data to display
  50  * @param len           Maximum length of buffer
  51  * @return 0 if ok, -1 if data does not match format
  52  */
  53 static int show_data(struct display_info *disp, const char *data, int len)
  54 {
  55         int i, size;
  56         const uint8_t *p = (const uint8_t *)data;
  57         const char *s;
  58         int value;
  59         int is_string;
  60         char fmt[3];
  61
  62         /* no data, don't print */
  63         if (len == 0)
  64                 return 0;
  65
  66         is_string = (disp->type) == 's' ||
  67                 (!disp->type && util_is_printable_string(data, len));
  68         if (is_string) {
  69                 if (data[len - 1] != '\0') {
  70                         fprintf(stderr, "Unterminated string\n");
  71                         return -1;
  72                 }
  73                 for (s = data; s - data < len; s += strlen(s) + 1) {
  74                         if (s != data)
  75                                 printf(" ");
  76                         printf("%s", (const char *)s);
  77                 }
  78                 return 0;
  79         }
  80         size = disp->size;
  81         if (size == -1) {
  82                 size = (len % 4) == 0 ? 4 : 1;
  83         } else if (len % size) {
  84                 fprintf(stderr, "Property length must be a multiple of "
  85                                 "selected data size\n");
  86                 return -1;
  87         }
  88         fmt[0] = '%';
  89         fmt[1] = disp->type ? disp->type : 'd';
  90         fmt[2] = '\0';
  91         for (i = 0; i < len; i += size, p += size) {
  92                 if (i)
  93                         printf(" ");
  94                 value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
  95                         size == 2 ? (*p << 8) | p[1] : *p;
  96                 printf(fmt, value);
  97         }
  98         return 0;
  99 }
 100
 101 /**
 102  * List all properties in a node, one per line.
 103  *
 104  * @param blob          FDT blob
 105  * @param node          Node to display
 106  * @return 0 if ok, or FDT_ERR... if not.
 107  */
 108 static int list_properties(const void *blob, int node)
 109 {
 110         const struct fdt_property *data;
 111         const char *name;
 112         int prop;
 113
 114         prop = fdt_first_property_offset(blob, node);
 115         do {
 116                 /* Stop silently when there are no more properties */
 117                 if (prop < 0)
 118                         return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
 119                 data = fdt_get_property_by_offset(blob, prop, NULL);
 120                 name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
 121                 if (name)
 122                         puts(name);
 123                 prop = fdt_next_property_offset(blob, prop);
 124         } while (1);
 125 }
 126
 127 #define MAX_LEVEL       32              /* how deeply nested we will go */
 128
 129 /**
 130  * List all subnodes in a node, one per line
 131  *
 132  * @param blob          FDT blob
 133  * @param node          Node to display
 134  * @return 0 if ok, or FDT_ERR... if not.
 135  */
 136 static int list_subnodes(const void *blob, int node)
 137 {
 138         int nextoffset;         /* next node offset from libfdt */
 139         uint32_t tag;           /* current tag */
 140         int level = 0;          /* keep track of nesting level */
 141         const char *pathp;
 142         int depth = 1;          /* the assumed depth of this node */
 143
 144         while (level >= 0) {
 145                 tag = fdt_next_tag(blob, node, &nextoffset);
 146                 switch (tag) {
 147                 case FDT_BEGIN_NODE:
 148                         pathp = fdt_get_name(blob, node, NULL);
 149                         if (level <= depth) {
 150                                 if (pathp == NULL)
 151                                         pathp = "/* NULL pointer error */";
 152                                 if (*pathp == '\0')
 153                                         pathp = "/";    /* root is nameless */
 154                                 if (level == 1)
 155                                         puts(pathp);
 156                         }
 157                         level++;
 158                         if (level >= MAX_LEVEL) {
 159                                 printf("Nested too deep, aborting.\n");
 160                                 return 1;
 161                         }
 162                         break;
 163                 case FDT_END_NODE:
 164                         level--;
 165                         if (level == 0)
 166                                 level = -1;             /* exit the loop */
 167                         break;
 168                 case FDT_END:
 169                         return 1;
 170                 case FDT_PROP:
 171                         break;
 172                 default:
 173                         if (level <= depth)
 174                                 printf("Unknown tag 0x%08X\n", tag);
 175                         return 1;
 176                 }
 177                 node = nextoffset;
 178         }
 179         return 0;
 180 }
 181
 182 /**
 183  * Show the data for a given node (and perhaps property) according to the
 184  * display option provided.
 185  *
 186  * @param blob          FDT blob
 187  * @param disp          Display information / options
 188  * @param node          Node to display
 189  * @param property      Name of property to display, or NULL if none
 190  * @return 0 if ok, -ve on error
 191  */
 192 static int show_data_for_item(const void *blob, struct display_info *disp,
 193                 int node, const char *property)
 194 {
 195         const void *value = NULL;
 196         int len, err = 0;
 197
 198         switch (disp->mode) {
 199         case MODE_LIST_PROPS:
 200                 err = list_properties(blob, node);
 201                 break;
 202
 203         case MODE_LIST_SUBNODES:
 204                 err = list_subnodes(blob, node);
 205                 break;
 206
 207         default:
 208                 assert(property);
 209                 value = fdt_getprop(blob, node, property, &len);
 210                 if (value) {
 211                         if (show_data(disp, value, len))
 212                                 err = -1;
 213                         else
 214                                 printf("\n");
 215                 } else if (disp->default_val) {
 216                         puts(disp->default_val);
 217                 } else {
 218                         report_error(property, len);
 219                         err = -1;
 220                 }
 221                 break;
 222         }
 223
 224         return err;
 225 }
 226
 227 /**
 228  * Run the main fdtget operation, given a filename and valid arguments
 229  *
 230  * @param disp          Display information / options
 231  * @param filename      Filename of blob file
 232  * @param arg           List of arguments to process
 233  * @param arg_count     Number of arguments
 234  * @param return 0 if ok, -ve on error
 235  */
 236 static int do_fdtget(struct display_info *disp, const char *filename,
 237                      char **arg, int arg_count, int args_per_step)
 238 {
 239         char *blob;
 240         const char *prop;
 241         int i, node;
 242
 243         blob = utilfdt_read(filename);
 244         if (!blob)
 245                 return -1;
 246
 247         for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
 248                 node = fdt_path_offset(blob, arg[i]);
 249                 if (node < 0) {
 250                         if (disp->default_val) {
 251                                 puts(disp->default_val);
 252                                 continue;
 253                         } else {
 254                                 report_error(arg[i], node);
 255                                 return -1;
 256                         }
 257                 }
 258                 prop = args_per_step == 1 ? NULL : arg[i + 1];
 259
 260                 if (show_data_for_item(blob, disp, node, prop))
 261                         return -1;
 262         }
 263         return 0;
 264 }
 265
 266 static const char *usage_msg =
 267         "fdtget - read values from device tree\n"
 268         "\n"
 269         "Each value is printed on a new line.\n\n"
 270         "Usage:\n"
 271         "       fdtget <options> <dt file> [<node> <property>]...\n"
 272         "       fdtget -p <options> <dt file> [<node> ]...\n"
 273         "Options:\n"
 274         "\t-t <type>\tType of data\n"
 275         "\t-p\t\tList properties for each node\n"
 276         "\t-l\t\tList subnodes for each node\n"
 277         "\t-d\t\tDefault value to display when the property is "
 278                         "missing\n"
 279         "\t-h\t\tPrint this help\n\n"
 280         USAGE_TYPE_MSG;
 281
 282 static void usage(const char *msg)
 283 {
 284         if (msg)
 285                 fprintf(stderr, "Error: %s\n\n", msg);
 286
 287         fprintf(stderr, "%s", usage_msg);
 288         exit(2);
 289 }
 290
 291 int main(int argc, char *argv[])
 292 {
 293         char *filename = NULL;
 294         struct display_info disp;
 295         int args_per_step = 2;
 296
 297         /* set defaults */
 298         memset(&disp, '\0', sizeof(disp));
 299         disp.size = -1;
 300         disp.mode = MODE_SHOW_VALUE;
 301         for (;;) {
 302                 int c = getopt(argc, argv, "d:hlpt:");
 303                 if (c == -1)
 304                         break;
 305
 306                 switch (c) {
 307                 case 'h':
 308                 case '?':
 309                         usage(NULL);
 310
 311                 case 't':
 312                         if (utilfdt_decode_type(optarg, &disp.type,
 313                                         &disp.size))
 314                                 usage("Invalid type string");
 315                         break;
 316
 317                 case 'p':
 318                         disp.mode = MODE_LIST_PROPS;
 319                         args_per_step = 1;
 320                         break;
 321
 322                 case 'l':
 323                         disp.mode = MODE_LIST_SUBNODES;
 324                         args_per_step = 1;
 325                         break;
 326
 327                 case 'd':
 328                         disp.default_val = optarg;
 329                         break;
 330                 }
 331         }
 332
 333         if (optind < argc)
 334                 filename = argv[optind++];
 335         if (!filename)
 336                 usage("Missing filename");
 337
 338         argv += optind;
 339         argc -= optind;
 340
 341         /* Allow no arguments, and silently succeed */
 342         if (!argc)
 343                 return 0;
 344
 345         /* Check for node, property arguments */
 346         if (args_per_step == 2 && (argc % 2))
 347                 usage("Must have an even number of arguments");
 348
 349         if (do_fdtget(&disp, filename, argv, argc, args_per_step))
 350                 return 1;
 351         return 0;
 352 }