qemu/softmmu/device_tree.c
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   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 "qemu/cutils.h"
  25#include "sysemu/device_tree.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  0x100000
  33
  34void *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;
  68fail:
  69    error_report("%s Couldn't create dt: %s", __func__, fdt_strerror(ret));
  70    exit(1);
  71}
  72
  73void *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    if (dt_size > INT_MAX / 2 - 10000) {
  88        error_report("Device tree file '%s' is too large", filename_path);
  89        goto fail;
  90    }
  91
  92    /* Expand to 2x size to give enough room for manipulation.  */
  93    dt_size += 10000;
  94    dt_size *= 2;
  95    /* First allocate space in qemu for device tree */
  96    fdt = g_malloc0(dt_size);
  97
  98    dt_file_load_size = load_image_size(filename_path, fdt, dt_size);
  99    if (dt_file_load_size < 0) {
 100        error_report("Unable to open device tree file '%s'",
 101                     filename_path);
 102        goto fail;
 103    }
 104
 105    ret = fdt_open_into(fdt, fdt, dt_size);
 106    if (ret) {
 107        error_report("Unable to copy device tree in memory");
 108        goto fail;
 109    }
 110
 111    /* Check sanity of device tree */
 112    if (fdt_check_header(fdt)) {
 113        error_report("Device tree file loaded into memory is invalid: %s",
 114                     filename_path);
 115        goto fail;
 116    }
 117    *sizep = dt_size;
 118    return fdt;
 119
 120fail:
 121    g_free(fdt);
 122    return NULL;
 123}
 124
 125#ifdef CONFIG_LINUX
 126
 127#define SYSFS_DT_BASEDIR "/proc/device-tree"
 128
 129/**
 130 * read_fstree: this function is inspired from dtc read_fstree
 131 * @fdt: preallocated fdt blob buffer, to be populated
 132 * @dirname: directory to scan under SYSFS_DT_BASEDIR
 133 * the search is recursive and the tree is searched down to the
 134 * leaves (property files).
 135 *
 136 * the function asserts in case of error
 137 */
 138static void read_fstree(void *fdt, const char *dirname)
 139{
 140    DIR *d;
 141    struct dirent *de;
 142    struct stat st;
 143    const char *root_dir = SYSFS_DT_BASEDIR;
 144    const char *parent_node;
 145
 146    if (strstr(dirname, root_dir) != dirname) {
 147        error_report("%s: %s must be searched within %s",
 148                     __func__, dirname, root_dir);
 149        exit(1);
 150    }
 151    parent_node = &dirname[strlen(SYSFS_DT_BASEDIR)];
 152
 153    d = opendir(dirname);
 154    if (!d) {
 155        error_report("%s cannot open %s", __func__, dirname);
 156        exit(1);
 157    }
 158
 159    while ((de = readdir(d)) != NULL) {
 160        char *tmpnam;
 161
 162        if (!g_strcmp0(de->d_name, ".")
 163            || !g_strcmp0(de->d_name, "..")) {
 164            continue;
 165        }
 166
 167        tmpnam = g_strdup_printf("%s/%s", dirname, de->d_name);
 168
 169        if (lstat(tmpnam, &st) < 0) {
 170            error_report("%s cannot lstat %s", __func__, tmpnam);
 171            exit(1);
 172        }
 173
 174        if (S_ISREG(st.st_mode)) {
 175            gchar *val;
 176            gsize len;
 177
 178            if (!g_file_get_contents(tmpnam, &val, &len, NULL)) {
 179                error_report("%s not able to extract info from %s",
 180                             __func__, tmpnam);
 181                exit(1);
 182            }
 183
 184            if (strlen(parent_node) > 0) {
 185                qemu_fdt_setprop(fdt, parent_node,
 186                                 de->d_name, val, len);
 187            } else {
 188                qemu_fdt_setprop(fdt, "/", de->d_name, val, len);
 189            }
 190            g_free(val);
 191        } else if (S_ISDIR(st.st_mode)) {
 192            char *node_name;
 193
 194            node_name = g_strdup_printf("%s/%s",
 195                                        parent_node, de->d_name);
 196            qemu_fdt_add_subnode(fdt, node_name);
 197            g_free(node_name);
 198            read_fstree(fdt, tmpnam);
 199        }
 200
 201        g_free(tmpnam);
 202    }
 203
 204    closedir(d);
 205}
 206
 207/* load_device_tree_from_sysfs: extract the dt blob from host sysfs */
 208void *load_device_tree_from_sysfs(void)
 209{
 210    void *host_fdt;
 211    int host_fdt_size;
 212
 213    host_fdt = create_device_tree(&host_fdt_size);
 214    read_fstree(host_fdt, SYSFS_DT_BASEDIR);
 215    if (fdt_check_header(host_fdt)) {
 216        error_report("%s host device tree extracted into memory is invalid",
 217                     __func__);
 218        exit(1);
 219    }
 220    return host_fdt;
 221}
 222
 223#endif /* CONFIG_LINUX */
 224
 225static int findnode_nofail(void *fdt, const char *node_path)
 226{
 227    int offset;
 228
 229    offset = fdt_path_offset(fdt, node_path);
 230    if (offset < 0) {
 231        error_report("%s Couldn't find node %s: %s", __func__, node_path,
 232                     fdt_strerror(offset));
 233        exit(1);
 234    }
 235
 236    return offset;
 237}
 238
 239char **qemu_fdt_node_unit_path(void *fdt, const char *name, Error **errp)
 240{
 241    char *prefix =  g_strdup_printf("%s@", name);
 242    unsigned int path_len = 16, n = 0;
 243    GSList *path_list = NULL, *iter;
 244    const char *iter_name;
 245    int offset, len, ret;
 246    char **path_array;
 247
 248    offset = fdt_next_node(fdt, -1, NULL);
 249
 250    while (offset >= 0) {
 251        iter_name = fdt_get_name(fdt, offset, &len);
 252        if (!iter_name) {
 253            offset = len;
 254            break;
 255        }
 256        if (!strcmp(iter_name, name) || g_str_has_prefix(iter_name, prefix)) {
 257            char *path;
 258
 259            path = g_malloc(path_len);
 260            while ((ret = fdt_get_path(fdt, offset, path, path_len))
 261                  == -FDT_ERR_NOSPACE) {
 262                path_len += 16;
 263                path = g_realloc(path, path_len);
 264            }
 265            path_list = g_slist_prepend(path_list, path);
 266            n++;
 267        }
 268        offset = fdt_next_node(fdt, offset, NULL);
 269    }
 270    g_free(prefix);
 271
 272    if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
 273        error_setg(errp, "%s: abort parsing dt for %s node units: %s",
 274                   __func__, name, fdt_strerror(offset));
 275        for (iter = path_list; iter; iter = iter->next) {
 276            g_free(iter->data);
 277        }
 278        g_slist_free(path_list);
 279        return NULL;
 280    }
 281
 282    path_array = g_new(char *, n + 1);
 283    path_array[n--] = NULL;
 284
 285    for (iter = path_list; iter; iter = iter->next) {
 286        path_array[n--] = iter->data;
 287    }
 288
 289    g_slist_free(path_list);
 290
 291    return path_array;
 292}
 293
 294char **qemu_fdt_node_path(void *fdt, const char *name, const char *compat,
 295                          Error **errp)
 296{
 297    int offset, len, ret;
 298    const char *iter_name;
 299    unsigned int path_len = 16, n = 0;
 300    GSList *path_list = NULL, *iter;
 301    char **path_array;
 302
 303    offset = fdt_node_offset_by_compatible(fdt, -1, compat);
 304
 305    while (offset >= 0) {
 306        iter_name = fdt_get_name(fdt, offset, &len);
 307        if (!iter_name) {
 308            offset = len;
 309            break;
 310        }
 311        if (!name || !strcmp(iter_name, name)) {
 312            char *path;
 313
 314            path = g_malloc(path_len);
 315            while ((ret = fdt_get_path(fdt, offset, path, path_len))
 316                  == -FDT_ERR_NOSPACE) {
 317                path_len += 16;
 318                path = g_realloc(path, path_len);
 319            }
 320            path_list = g_slist_prepend(path_list, path);
 321            n++;
 322        }
 323        offset = fdt_node_offset_by_compatible(fdt, offset, compat);
 324    }
 325
 326    if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
 327        error_setg(errp, "%s: abort parsing dt for %s/%s: %s",
 328                   __func__, name, compat, fdt_strerror(offset));
 329        for (iter = path_list; iter; iter = iter->next) {
 330            g_free(iter->data);
 331        }
 332        g_slist_free(path_list);
 333        return NULL;
 334    }
 335
 336    path_array = g_new(char *, n + 1);
 337    path_array[n--] = NULL;
 338
 339    for (iter = path_list; iter; iter = iter->next) {
 340        path_array[n--] = iter->data;
 341    }
 342
 343    g_slist_free(path_list);
 344
 345    return path_array;
 346}
 347
 348int qemu_fdt_setprop(void *fdt, const char *node_path,
 349                     const char *property, const void *val, int size)
 350{
 351    int r;
 352
 353    r = fdt_setprop(fdt, findnode_nofail(fdt, node_path), property, val, size);
 354    if (r < 0) {
 355        error_report("%s: Couldn't set %s/%s: %s", __func__, node_path,
 356                     property, fdt_strerror(r));
 357        exit(1);
 358    }
 359
 360    return r;
 361}
 362
 363int qemu_fdt_setprop_cell(void *fdt, const char *node_path,
 364                          const char *property, uint32_t val)
 365{
 366    int r;
 367
 368    r = fdt_setprop_cell(fdt, findnode_nofail(fdt, node_path), property, val);
 369    if (r < 0) {
 370        error_report("%s: Couldn't set %s/%s = %#08x: %s", __func__,
 371                     node_path, property, val, fdt_strerror(r));
 372        exit(1);
 373    }
 374
 375    return r;
 376}
 377
 378int qemu_fdt_setprop_u64(void *fdt, const char *node_path,
 379                         const char *property, uint64_t val)
 380{
 381    val = cpu_to_be64(val);
 382    return qemu_fdt_setprop(fdt, node_path, property, &val, sizeof(val));
 383}
 384
 385int qemu_fdt_setprop_string(void *fdt, const char *node_path,
 386                            const char *property, const char *string)
 387{
 388    int r;
 389
 390    r = fdt_setprop_string(fdt, findnode_nofail(fdt, node_path), property, string);
 391    if (r < 0) {
 392        error_report("%s: Couldn't set %s/%s = %s: %s", __func__,
 393                     node_path, property, string, fdt_strerror(r));
 394        exit(1);
 395    }
 396
 397    return r;
 398}
 399
 400/*
 401 * libfdt doesn't allow us to add string arrays directly but they are
 402 * test a series of null terminated strings with a length. We build
 403 * the string up here so we can calculate the final length.
 404 */
 405int qemu_fdt_setprop_string_array(void *fdt, const char *node_path,
 406                                  const char *prop, char **array, int len)
 407{
 408    int ret, i, total_len = 0;
 409    char *str, *p;
 410    for (i = 0; i < len; i++) {
 411        total_len += strlen(array[i]) + 1;
 412    }
 413    p = str = g_malloc0(total_len);
 414    for (i = 0; i < len; i++) {
 415        int len = strlen(array[i]) + 1;
 416        pstrcpy(p, len, array[i]);
 417        p += len;
 418    }
 419
 420    ret = qemu_fdt_setprop(fdt, node_path, prop, str, total_len);
 421    g_free(str);
 422    return ret;
 423}
 424
 425const void *qemu_fdt_getprop(void *fdt, const char *node_path,
 426                             const char *property, int *lenp, Error **errp)
 427{
 428    int len;
 429    const void *r;
 430
 431    if (!lenp) {
 432        lenp = &len;
 433    }
 434    r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);
 435    if (!r) {
 436        error_setg(errp, "%s: Couldn't get %s/%s: %s", __func__,
 437                  node_path, property, fdt_strerror(*lenp));
 438    }
 439    return r;
 440}
 441
 442uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
 443                               const char *property, int *lenp, Error **errp)
 444{
 445    int len;
 446    const uint32_t *p;
 447
 448    if (!lenp) {
 449        lenp = &len;
 450    }
 451    p = qemu_fdt_getprop(fdt, node_path, property, lenp, errp);
 452    if (!p) {
 453        return 0;
 454    } else if (*lenp != 4) {
 455        error_setg(errp, "%s: %s/%s not 4 bytes long (not a cell?)",
 456                   __func__, node_path, property);
 457        *lenp = -EINVAL;
 458        return 0;
 459    }
 460    return be32_to_cpu(*p);
 461}
 462
 463uint32_t qemu_fdt_get_phandle(void *fdt, const char *path)
 464{
 465    uint32_t r;
 466
 467    r = fdt_get_phandle(fdt, findnode_nofail(fdt, path));
 468    if (r == 0) {
 469        error_report("%s: Couldn't get phandle for %s: %s", __func__,
 470                     path, fdt_strerror(r));
 471        exit(1);
 472    }
 473
 474    return r;
 475}
 476
 477int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
 478                             const char *property,
 479                             const char *target_node_path)
 480{
 481    uint32_t phandle = qemu_fdt_get_phandle(fdt, target_node_path);
 482    return qemu_fdt_setprop_cell(fdt, node_path, property, phandle);
 483}
 484
 485uint32_t qemu_fdt_alloc_phandle(void *fdt)
 486{
 487    static int phandle = 0x0;
 488
 489    /*
 490     * We need to find out if the user gave us special instruction at
 491     * which phandle id to start allocating phandles.
 492     */
 493    if (!phandle) {
 494        phandle = machine_phandle_start(current_machine);
 495    }
 496
 497    if (!phandle) {
 498        /*
 499         * None or invalid phandle given on the command line, so fall back to
 500         * default starting point.
 501         */
 502        phandle = 0x8000;
 503    }
 504
 505    return phandle++;
 506}
 507
 508int qemu_fdt_nop_node(void *fdt, const char *node_path)
 509{
 510    int r;
 511
 512    r = fdt_nop_node(fdt, findnode_nofail(fdt, node_path));
 513    if (r < 0) {
 514        error_report("%s: Couldn't nop node %s: %s", __func__, node_path,
 515                     fdt_strerror(r));
 516        exit(1);
 517    }
 518
 519    return r;
 520}
 521
 522int qemu_fdt_add_subnode(void *fdt, const char *name)
 523{
 524    char *dupname = g_strdup(name);
 525    char *basename = strrchr(dupname, '/');
 526    int retval;
 527    int parent = 0;
 528
 529    if (!basename) {
 530        g_free(dupname);
 531        return -1;
 532    }
 533
 534    basename[0] = '\0';
 535    basename++;
 536
 537    if (dupname[0]) {
 538        parent = findnode_nofail(fdt, dupname);
 539    }
 540
 541    retval = fdt_add_subnode(fdt, parent, basename);
 542    if (retval < 0) {
 543        error_report("%s: Failed to create subnode %s: %s",
 544                     __func__, name, fdt_strerror(retval));
 545        exit(1);
 546    }
 547
 548    g_free(dupname);
 549    return retval;
 550}
 551
 552/*
 553 * qemu_fdt_add_path: Like qemu_fdt_add_subnode(), but will add
 554 * all missing subnodes from the given path.
 555 */
 556int qemu_fdt_add_path(void *fdt, const char *path)
 557{
 558    const char *name;
 559    const char *p = path;
 560    int namelen, retval;
 561    int parent = 0;
 562
 563    if (path[0] != '/') {
 564        return -1;
 565    }
 566
 567    while (p) {
 568        name = p + 1;
 569        p = strchr(name, '/');
 570        namelen = p != NULL ? p - name : strlen(name);
 571
 572        retval = fdt_subnode_offset_namelen(fdt, parent, name, namelen);
 573        if (retval < 0 && retval != -FDT_ERR_NOTFOUND) {
 574            error_report("%s: Unexpected error in finding subnode %.*s: %s",
 575                         __func__, namelen, name, fdt_strerror(retval));
 576            exit(1);
 577        } else if (retval == -FDT_ERR_NOTFOUND) {
 578            retval = fdt_add_subnode_namelen(fdt, parent, name, namelen);
 579            if (retval < 0) {
 580                error_report("%s: Failed to create subnode %.*s: %s",
 581                             __func__, namelen, name, fdt_strerror(retval));
 582                exit(1);
 583            }
 584        }
 585
 586        parent = retval;
 587    }
 588
 589    return retval;
 590}
 591
 592void qemu_fdt_dumpdtb(void *fdt, int size)
 593{
 594    const char *dumpdtb = current_machine->dumpdtb;
 595
 596    if (dumpdtb) {
 597        /* Dump the dtb to a file and quit */
 598        if (g_file_set_contents(dumpdtb, fdt, size, NULL)) {
 599            info_report("dtb dumped to %s. Exiting.", dumpdtb);
 600            exit(0);
 601        }
 602        error_report("%s: Failed dumping dtb to %s", __func__, dumpdtb);
 603        exit(1);
 604    }
 605}
 606
 607int qemu_fdt_setprop_sized_cells_from_array(void *fdt,
 608                                            const char *node_path,
 609                                            const char *property,
 610                                            int numvalues,
 611                                            uint64_t *values)
 612{
 613    uint32_t *propcells;
 614    uint64_t value;
 615    int cellnum, vnum, ncells;
 616    uint32_t hival;
 617    int ret;
 618
 619    propcells = g_new0(uint32_t, numvalues * 2);
 620
 621    cellnum = 0;
 622    for (vnum = 0; vnum < numvalues; vnum++) {
 623        ncells = values[vnum * 2];
 624        if (ncells != 1 && ncells != 2) {
 625            ret = -1;
 626            goto out;
 627        }
 628        value = values[vnum * 2 + 1];
 629        hival = cpu_to_be32(value >> 32);
 630        if (ncells > 1) {
 631            propcells[cellnum++] = hival;
 632        } else if (hival != 0) {
 633            ret = -1;
 634            goto out;
 635        }
 636        propcells[cellnum++] = cpu_to_be32(value);
 637    }
 638
 639    ret = qemu_fdt_setprop(fdt, node_path, property, propcells,
 640                           cellnum * sizeof(uint32_t));
 641out:
 642    g_free(propcells);
 643    return ret;
 644}
 645