device_tree.c

   1 /*
   2  * Functions to help device tree manipulation using libfdt.
   3  * It also provides functions to read entries from device tree proc
   4  * interface.
   5  *
   6  * Copyright 2008 IBM Corporation.
   7  * Authors: Jerone Young <jyoung5@us.ibm.com>
   8  *          Hollis Blanchard <hollisb@us.ibm.com>
   9  *
  10  * This work is licensed under the GNU GPL license version 2 or later.
  11  *
  12  */
  13
  14 #include "qemu/osdep.h"
  15
  16 #ifdef CONFIG_LINUX
  17 #include <dirent.h>
  18 #endif
  19
  20 #include "qapi/error.h"
  21 #include "qemu/error-report.h"
  22 #include "qemu/option.h"
  23 #include "qemu/bswap.h"
  24 #include "sysemu/device_tree.h"
  25 #include "sysemu/sysemu.h"
  26 #include "hw/loader.h"
  27 #include "hw/boards.h"
  28 #include "qemu/config-file.h"
  29
  30 #include <libfdt.h>
  31
  32 #define FDT_MAX_SIZE  0x10000
  33
  34 void *create_device_tree(int *sizep)
  35 {
  36     void *fdt;
  37     int ret;
  38
  39     *sizep = FDT_MAX_SIZE;
  40     fdt = g_malloc0(FDT_MAX_SIZE);
  41     ret = fdt_create(fdt, FDT_MAX_SIZE);
  42     if (ret < 0) {
  43         goto fail;
  44     }
  45     ret = fdt_finish_reservemap(fdt);
  46     if (ret < 0) {
  47         goto fail;
  48     }
  49     ret = fdt_begin_node(fdt, "");
  50     if (ret < 0) {
  51         goto fail;
  52     }
  53     ret = fdt_end_node(fdt);
  54     if (ret < 0) {
  55         goto fail;
  56     }
  57     ret = fdt_finish(fdt);
  58     if (ret < 0) {
  59         goto fail;
  60     }
  61     ret = fdt_open_into(fdt, fdt, *sizep);
  62     if (ret) {
  63         error_report("Unable to copy device tree in memory");
  64         exit(1);
  65     }
  66
  67     return fdt;
  68 fail:
  69     error_report("%s Couldn't create dt: %s", __func__, fdt_strerror(ret));
  70     exit(1);
  71 }
  72
  73 void *load_device_tree(const char *filename_path, int *sizep)
  74 {
  75     int dt_size;
  76     int dt_file_load_size;
  77     int ret;
  78     void *fdt = NULL;
  79
  80     *sizep = 0;
  81     dt_size = get_image_size(filename_path);
  82     if (dt_size < 0) {
  83         error_report("Unable to get size of device tree file '%s'",
  84                      filename_path);
  85         goto fail;
  86     }
  87
  88     /* Expand to 2x size to give enough room for manipulation.  */
  89     dt_size += 10000;
  90     dt_size *= 2;
  91     /* First allocate space in qemu for device tree */
  92     fdt = g_malloc0(dt_size);
  93
  94     dt_file_load_size = load_image(filename_path, fdt);
  95     if (dt_file_load_size < 0) {
  96         error_report("Unable to open device tree file '%s'",
  97                      filename_path);
  98         goto fail;
  99     }
 100
 101     ret = fdt_open_into(fdt, fdt, dt_size);
 102     if (ret) {
 103         error_report("Unable to copy device tree in memory");
 104         goto fail;
 105     }
 106
 107     /* Check sanity of device tree */
 108     if (fdt_check_header(fdt)) {
 109         error_report("Device tree file loaded into memory is invalid: %s",
 110                      filename_path);
 111         goto fail;
 112     }
 113     *sizep = dt_size;
 114     return fdt;
 115
 116 fail:
 117     g_free(fdt);
 118     return NULL;
 119 }
 120
 121 #ifdef CONFIG_LINUX
 122
 123 #define SYSFS_DT_BASEDIR "/proc/device-tree"
 124
 125 /**
 126  * read_fstree: this function is inspired from dtc read_fstree
 127  * @fdt: preallocated fdt blob buffer, to be populated
 128  * @dirname: directory to scan under SYSFS_DT_BASEDIR
 129  * the search is recursive and the tree is searched down to the
 130  * leaves (property files).
 131  *
 132  * the function asserts in case of error
 133  */
 134 static void read_fstree(void *fdt, const char *dirname)
 135 {
 136     DIR *d;
 137     struct dirent *de;
 138     struct stat st;
 139     const char *root_dir = SYSFS_DT_BASEDIR;
 140     const char *parent_node;
 141
 142     if (strstr(dirname, root_dir) != dirname) {
 143         error_setg(&error_fatal, "%s: %s must be searched within %s",
 144                    __func__, dirname, root_dir);
 145     }
 146     parent_node = &dirname[strlen(SYSFS_DT_BASEDIR)];
 147
 148     d = opendir(dirname);
 149     if (!d) {
 150         error_setg(&error_fatal, "%s cannot open %s", __func__, dirname);
 151         return;
 152     }
 153
 154     while ((de = readdir(d)) != NULL) {
 155         char *tmpnam;
 156
 157         if (!g_strcmp0(de->d_name, ".")
 158             || !g_strcmp0(de->d_name, "..")) {
 159             continue;
 160         }
 161
 162         tmpnam = g_strdup_printf("%s/%s", dirname, de->d_name);
 163
 164         if (lstat(tmpnam, &st) < 0) {
 165             error_setg(&error_fatal, "%s cannot lstat %s", __func__, tmpnam);
 166         }
 167
 168         if (S_ISREG(st.st_mode)) {
 169             gchar *val;
 170             gsize len;
 171
 172             if (!g_file_get_contents(tmpnam, &val, &len, NULL)) {
 173                 error_setg(&error_fatal, "%s not able to extract info from %s",
 174                            __func__, tmpnam);
 175             }
 176
 177             if (strlen(parent_node) > 0) {
 178                 qemu_fdt_setprop(fdt, parent_node,
 179                                  de->d_name, val, len);
 180             } else {
 181                 qemu_fdt_setprop(fdt, "/", de->d_name, val, len);
 182             }
 183             g_free(val);
 184         } else if (S_ISDIR(st.st_mode)) {
 185             char *node_name;
 186
 187             node_name = g_strdup_printf("%s/%s",
 188                                         parent_node, de->d_name);
 189             qemu_fdt_add_subnode(fdt, node_name);
 190             g_free(node_name);
 191             read_fstree(fdt, tmpnam);
 192         }
 193
 194         g_free(tmpnam);
 195     }
 196
 197     closedir(d);
 198 }
 199
 200 /* load_device_tree_from_sysfs: extract the dt blob from host sysfs */
 201 void *load_device_tree_from_sysfs(void)
 202 {
 203     void *host_fdt;
 204     int host_fdt_size;
 205
 206     host_fdt = create_device_tree(&host_fdt_size);
 207     read_fstree(host_fdt, SYSFS_DT_BASEDIR);
 208     if (fdt_check_header(host_fdt)) {
 209         error_setg(&error_fatal,
 210                    "%s host device tree extracted into memory is invalid",
 211                    __func__);
 212     }
 213     return host_fdt;
 214 }
 215
 216 #endif /* CONFIG_LINUX */
 217
 218 static int findnode_nofail(void *fdt, const char *node_path)
 219 {
 220     int offset;
 221
 222     offset = fdt_path_offset(fdt, node_path);
 223     if (offset < 0) {
 224         error_report("%s Couldn't find node %s: %s", __func__, node_path,
 225                      fdt_strerror(offset));
 226         exit(1);
 227     }
 228
 229     return offset;
 230 }
 231
 232 char **qemu_fdt_node_path(void *fdt, const char *name, char *compat,
 233                           Error **errp)
 234 {
 235     int offset, len, ret;
 236     const char *iter_name;
 237     unsigned int path_len = 16, n = 0;
 238     GSList *path_list = NULL, *iter;
 239     char **path_array;
 240
 241     offset = fdt_node_offset_by_compatible(fdt, -1, compat);
 242
 243     while (offset >= 0) {
 244         iter_name = fdt_get_name(fdt, offset, &len);
 245         if (!iter_name) {
 246             offset = len;
 247             break;
 248         }
 249         if (!strcmp(iter_name, name)) {
 250             char *path;
 251
 252             path = g_malloc(path_len);
 253             while ((ret = fdt_get_path(fdt, offset, path, path_len))
 254                   == -FDT_ERR_NOSPACE) {
 255                 path_len += 16;
 256                 path = g_realloc(path, path_len);
 257             }
 258             path_list = g_slist_prepend(path_list, path);
 259             n++;
 260         }
 261         offset = fdt_node_offset_by_compatible(fdt, offset, compat);
 262     }
 263
 264     if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
 265         error_setg(errp, "%s: abort parsing dt for %s/%s: %s",
 266                    __func__, name, compat, fdt_strerror(offset));
 267         for (iter = path_list; iter; iter = iter->next) {
 268             g_free(iter->data);
 269         }
 270         g_slist_free(path_list);
 271         return NULL;
 272     }
 273
 274     path_array = g_new(char *, n + 1);
 275     path_array[n--] = NULL;
 276
 277     for (iter = path_list; iter; iter = iter->next) {
 278         path_array[n--] = iter->data;
 279     }
 280
 281     g_slist_free(path_list);
 282
 283     return path_array;
 284 }
 285
 286 int qemu_fdt_setprop(void *fdt, const char *node_path,
 287                      const char *property, const void *val, int size)
 288 {
 289     int r;
 290
 291     r = fdt_setprop(fdt, findnode_nofail(fdt, node_path), property, val, size);
 292     if (r < 0) {
 293         error_report("%s: Couldn't set %s/%s: %s", __func__, node_path,
 294                      property, fdt_strerror(r));
 295         exit(1);
 296     }
 297
 298     return r;
 299 }
 300
 301 int qemu_fdt_setprop_cell(void *fdt, const char *node_path,
 302                           const char *property, uint32_t val)
 303 {
 304     int r;
 305
 306     r = fdt_setprop_cell(fdt, findnode_nofail(fdt, node_path), property, val);
 307     if (r < 0) {
 308         error_report("%s: Couldn't set %s/%s = %#08x: %s", __func__,
 309                      node_path, property, val, fdt_strerror(r));
 310         exit(1);
 311     }
 312
 313     return r;
 314 }
 315
 316 int qemu_fdt_setprop_u64(void *fdt, const char *node_path,
 317                          const char *property, uint64_t val)
 318 {
 319     val = cpu_to_be64(val);
 320     return qemu_fdt_setprop(fdt, node_path, property, &val, sizeof(val));
 321 }
 322
 323 int qemu_fdt_setprop_string(void *fdt, const char *node_path,
 324                             const char *property, const char *string)
 325 {
 326     int r;
 327
 328     r = fdt_setprop_string(fdt, findnode_nofail(fdt, node_path), property, string);
 329     if (r < 0) {
 330         error_report("%s: Couldn't set %s/%s = %s: %s", __func__,
 331                      node_path, property, string, fdt_strerror(r));
 332         exit(1);
 333     }
 334
 335     return r;
 336 }
 337
 338 const void *qemu_fdt_getprop(void *fdt, const char *node_path,
 339                              const char *property, int *lenp, Error **errp)
 340 {
 341     int len;
 342     const void *r;
 343
 344     if (!lenp) {
 345         lenp = &len;
 346     }
 347     r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);
 348     if (!r) {
 349         error_setg(errp, "%s: Couldn't get %s/%s: %s", __func__,
 350                   node_path, property, fdt_strerror(*lenp));
 351     }
 352     return r;
 353 }
 354
 355 uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
 356                                const char *property, int *lenp, Error **errp)
 357 {
 358     int len;
 359     const uint32_t *p;
 360
 361     if (!lenp) {
 362         lenp = &len;
 363     }
 364     p = qemu_fdt_getprop(fdt, node_path, property, lenp, errp);
 365     if (!p) {
 366         return 0;
 367     } else if (*lenp != 4) {
 368         error_setg(errp, "%s: %s/%s not 4 bytes long (not a cell?)",
 369                    __func__, node_path, property);
 370         *lenp = -EINVAL;
 371         return 0;
 372     }
 373     return be32_to_cpu(*p);
 374 }
 375
 376 uint32_t qemu_fdt_get_phandle(void *fdt, const char *path)
 377 {
 378     uint32_t r;
 379
 380     r = fdt_get_phandle(fdt, findnode_nofail(fdt, path));
 381     if (r == 0) {
 382         error_report("%s: Couldn't get phandle for %s: %s", __func__,
 383                      path, fdt_strerror(r));
 384         exit(1);
 385     }
 386
 387     return r;
 388 }
 389
 390 int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
 391                              const char *property,
 392                              const char *target_node_path)
 393 {
 394     uint32_t phandle = qemu_fdt_get_phandle(fdt, target_node_path);
 395     return qemu_fdt_setprop_cell(fdt, node_path, property, phandle);
 396 }
 397
 398 uint32_t qemu_fdt_alloc_phandle(void *fdt)
 399 {
 400     static int phandle = 0x0;
 401
 402     /*
 403      * We need to find out if the user gave us special instruction at
 404      * which phandle id to start allocating phandles.
 405      */
 406     if (!phandle) {
 407         phandle = machine_phandle_start(current_machine);
 408     }
 409
 410     if (!phandle) {
 411         /*
 412          * None or invalid phandle given on the command line, so fall back to
 413          * default starting point.
 414          */
 415         phandle = 0x8000;
 416     }
 417
 418     return phandle++;
 419 }
 420
 421 int qemu_fdt_nop_node(void *fdt, const char *node_path)
 422 {
 423     int r;
 424
 425     r = fdt_nop_node(fdt, findnode_nofail(fdt, node_path));
 426     if (r < 0) {
 427         error_report("%s: Couldn't nop node %s: %s", __func__, node_path,
 428                      fdt_strerror(r));
 429         exit(1);
 430     }
 431
 432     return r;
 433 }
 434
 435 int qemu_fdt_add_subnode(void *fdt, const char *name)
 436 {
 437     char *dupname = g_strdup(name);
 438     char *basename = strrchr(dupname, '/');
 439     int retval;
 440     int parent = 0;
 441
 442     if (!basename) {
 443         g_free(dupname);
 444         return -1;
 445     }
 446
 447     basename[0] = '\0';
 448     basename++;
 449
 450     if (dupname[0]) {
 451         parent = findnode_nofail(fdt, dupname);
 452     }
 453
 454     retval = fdt_add_subnode(fdt, parent, basename);
 455     if (retval < 0) {
 456         error_report("FDT: Failed to create subnode %s: %s", name,
 457                      fdt_strerror(retval));
 458         exit(1);
 459     }
 460
 461     g_free(dupname);
 462     return retval;
 463 }
 464
 465 void qemu_fdt_dumpdtb(void *fdt, int size)
 466 {
 467     const char *dumpdtb = qemu_opt_get(qemu_get_machine_opts(), "dumpdtb");
 468
 469     if (dumpdtb) {
 470         /* Dump the dtb to a file and quit */
 471         exit(g_file_set_contents(dumpdtb, fdt, size, NULL) ? 0 : 1);
 472     }
 473 }
 474
 475 int qemu_fdt_setprop_sized_cells_from_array(void *fdt,
 476                                             const char *node_path,
 477                                             const char *property,
 478                                             int numvalues,
 479                                             uint64_t *values)
 480 {
 481     uint32_t *propcells;
 482     uint64_t value;
 483     int cellnum, vnum, ncells;
 484     uint32_t hival;
 485     int ret;
 486
 487     propcells = g_new0(uint32_t, numvalues * 2);
 488
 489     cellnum = 0;
 490     for (vnum = 0; vnum < numvalues; vnum++) {
 491         ncells = values[vnum * 2];
 492         if (ncells != 1 && ncells != 2) {
 493             ret = -1;
 494             goto out;
 495         }
 496         value = values[vnum * 2 + 1];
 497         hival = cpu_to_be32(value >> 32);
 498         if (ncells > 1) {
 499             propcells[cellnum++] = hival;
 500         } else if (hival != 0) {
 501             ret = -1;
 502             goto out;
 503         }
 504         propcells[cellnum++] = cpu_to_be32(value);
 505     }
 506
 507     ret = qemu_fdt_setprop(fdt, node_path, property, propcells,
 508                            cellnum * sizeof(uint32_t));
 509 out:
 510     g_free(propcells);
 511     return ret;
 512 }