libfdt-wrapper.c

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/*
 * This file does the necessary interface mapping between the bootwrapper
 * device tree operations and the interface provided by shared source
 * files flatdevicetree.[ch].
 *
 * Copyright 2007 David Gibson, IBM Corporation.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <stddef.h>
#include <stdio.h>
#include <page.h>
#include <libfdt.h>
#include "ops.h"

#define DEBUG   0
#define BAD_ERROR(err)  (((err) < 0) \
             && ((err) != -FDT_ERR_NOTFOUND) \
             && ((err) != -FDT_ERR_EXISTS))

#define check_err(err) \
    ({ \
        if (BAD_ERROR(err) || ((err < 0) && DEBUG)) \
            printf("%s():%d  %s\n\r", __func__, __LINE__, \
                   fdt_strerror(err)); \
        if (BAD_ERROR(err)) \
            exit(); \
        (err < 0) ? -1 : 0; \
    })

#define offset_devp(off)    \
    ({ \
        int _offset = (off); \
        check_err(_offset) ? NULL : (void *)(_offset+1); \
    })

#define devp_offset_find(devp)  (((int)(devp))-1)
#define devp_offset(devp)   (devp ? ((int)(devp))-1 : 0)

static void *fdt;
static void *buf; /* = NULL */

#define EXPAND_GRANULARITY  1024

static void expand_buf(int minexpand)
{
    int size = fdt_totalsize(fdt);
    int rc;

    size = _ALIGN(size + minexpand, EXPAND_GRANULARITY);
    buf = platform_ops.realloc(buf, size);
    if (!buf)
        fatal("Couldn't find %d bytes to expand device tree\n\r", size);
    rc = fdt_open_into(fdt, buf, size);
    if (rc != 0)
        fatal("Couldn't expand fdt into new buffer: %s\n\r",
              fdt_strerror(rc));

    fdt = buf;
}

static void *fdt_wrapper_finddevice(const char *path)
{
    return offset_devp(fdt_path_offset(fdt, path));
}

static int fdt_wrapper_getprop(const void *devp, const char *name,
                   void *buf, const int buflen)
{
    const void *p;
    int len;

    p = fdt_getprop(fdt, devp_offset(devp), name, &len);
    if (!p)
        return check_err(len);
    memcpy(buf, p, min(len, buflen));
    return len;
}

static int fdt_wrapper_setprop(const void *devp, const char *name,
                   const void *buf, const int len)
{
    int rc;

    rc = fdt_setprop(fdt, devp_offset(devp), name, buf, len);
    if (rc == -FDT_ERR_NOSPACE) {
        expand_buf(len + 16);
        rc = fdt_setprop(fdt, devp_offset(devp), name, buf, len);
    }

    return check_err(rc);
}

static int fdt_wrapper_del_node(const void *devp)
{
    return fdt_del_node(fdt, devp_offset(devp));
}

static void *fdt_wrapper_get_parent(const void *devp)
{
    return offset_devp(fdt_parent_offset(fdt, devp_offset(devp)));
}

static void *fdt_wrapper_create_node(const void *devp, const char *name)
{
    int offset;

    offset = fdt_add_subnode(fdt, devp_offset(devp), name);
    if (offset == -FDT_ERR_NOSPACE) {
        expand_buf(strlen(name) + 16);
        offset = fdt_add_subnode(fdt, devp_offset(devp), name);
    }

    return offset_devp(offset);
}

static void *fdt_wrapper_find_node_by_prop_value(const void *prev,
                         const char *name,
                         const char *val,
                         int len)
{
    int offset = fdt_node_offset_by_prop_value(fdt, devp_offset_find(prev),
                                               name, val, len);
    return offset_devp(offset);
}

static void *fdt_wrapper_find_node_by_compatible(const void *prev,
                         const char *val)
{
    int offset = fdt_node_offset_by_compatible(fdt, devp_offset_find(prev),
                                               val);
    return offset_devp(offset);
}

static char *fdt_wrapper_get_path(const void *devp, char *buf, int len)
{
    int rc;

    rc = fdt_get_path(fdt, devp_offset(devp), buf, len);
    if (check_err(rc))
        return NULL;
    return buf;
}

static unsigned long fdt_wrapper_finalize(void)
{
    int rc;

    rc = fdt_pack(fdt);
    if (rc != 0)
        fatal("Couldn't pack flat tree: %s\n\r",
              fdt_strerror(rc));
    return (unsigned long)fdt;
}

void fdt_init(void *blob)
{
    int err;
    int bufsize;

    dt_ops.finddevice = fdt_wrapper_finddevice;
    dt_ops.getprop = fdt_wrapper_getprop;
    dt_ops.setprop = fdt_wrapper_setprop;
    dt_ops.get_parent = fdt_wrapper_get_parent;
    dt_ops.create_node = fdt_wrapper_create_node;
    dt_ops.find_node_by_prop_value = fdt_wrapper_find_node_by_prop_value;
    dt_ops.find_node_by_compatible = fdt_wrapper_find_node_by_compatible;
    dt_ops.del_node = fdt_wrapper_del_node;
    dt_ops.get_path = fdt_wrapper_get_path;
    dt_ops.finalize = fdt_wrapper_finalize;

    /* Make sure the dt blob is the right version and so forth */
    fdt = blob;
    bufsize = fdt_totalsize(fdt) + EXPAND_GRANULARITY;
    buf = malloc(bufsize);
    if(!buf)
        fatal("malloc failed. can't relocate the device tree\n\r");

    err = fdt_open_into(fdt, buf, bufsize);

    if (err != 0)
        fatal("fdt_init(): %s\n\r", fdt_strerror(err));

    fdt = buf;
}