/*
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright Pantelis Antoniou 2006
 * Copyright (C) IBM Corporation 2006
 *
 * Authors: Pantelis Antoniou <pantelis@embeddedalley.com>
 *          Hollis Blanchard <hollisb@us.ibm.com>
 *          Mark A. Greer <mgreer@mvista.com>
 *          Paul Mackerras <paulus@samba.org>
 */

#include <string.h>
#include <stddef.h>
#include "flatdevtree.h"
#include "flatdevtree_env.h"

#define _ALIGN(x, al)   (((x) + (al) - 1) & ~((al) - 1))

static char *ft_root_node(struct ft_cxt *cxt)
{
        return cxt->rgn[FT_STRUCT].start;
}

/* Routines for keeping node ptrs returned by ft_find_device current */
/* First entry not used b/c it would return 0 and be taken as NULL/error */
static void *ft_get_phandle(struct ft_cxt *cxt, char *node)
{
        unsigned int i;

        if (!node)
                return NULL;

        for (i = 1; i < cxt->nodes_used; i++)   /* already there? */
                if (cxt->node_tbl[i] == node)
                        return (void *)i;

        if (cxt->nodes_used < cxt->node_max) {
                cxt->node_tbl[cxt->nodes_used] = node;
                return (void *)cxt->nodes_used++;
        }

        return NULL;
}

static char *ft_node_ph2node(struct ft_cxt *cxt, const void *phandle)
{
        unsigned int i = (unsigned int)phandle;

        if (i < cxt->nodes_used)
                return cxt->node_tbl[i];
        return NULL;
}

static void ft_node_update_before(struct ft_cxt *cxt, char *addr, int shift)
{
        unsigned int i;

        if (shift == 0)
                return;

        for (i = 1; i < cxt->nodes_used; i++)
                if (cxt->node_tbl[i] < addr)
                        cxt->node_tbl[i] += shift;
}

static void ft_node_update_after(struct ft_cxt *cxt, char *addr, int shift)
{
        unsigned int i;

        if (shift == 0)
                return;

        for (i = 1; i < cxt->nodes_used; i++)
                if (cxt->node_tbl[i] >= addr)
                        cxt->node_tbl[i] += shift;
}

/* Struct used to return info from ft_next() */
struct ft_atom {
        u32 tag;
        const char *name;
        void *data;
        u32 size;
};

/* Set ptrs to current one's info; return addr of next one */
static char *ft_next(struct ft_cxt *cxt, char *p, struct ft_atom *ret)
{
        u32 sz;

        if (p >= cxt->rgn[FT_STRUCT].start + cxt->rgn[FT_STRUCT].size)
                return NULL;

        ret->tag = be32_to_cpu(*(u32 *) p);
        p += 4;

        switch (ret->tag) {     /* Tag */
        case OF_DT_BEGIN_NODE:
                ret->name = p;
                ret->data = (void *)(p - 4);    /* start of node */
                p += _ALIGN(strlen(p) + 1, 4);
                break;
        case OF_DT_PROP:
                ret->size = sz = be32_to_cpu(*(u32 *) p);
                ret->name = cxt->str_anchor + be32_to_cpu(*(u32 *) (p + 4));
                ret->data = (void *)(p + 8);
                p += 8 + _ALIGN(sz, 4);
                break;
        case OF_DT_END_NODE:
        case OF_DT_NOP:
                break;
        case OF_DT_END:
        default:
                p = NULL;
                break;
        }

        return p;
}

#define HDR_SIZE        _ALIGN(sizeof(struct boot_param_header), 8)
#define EXPAND_INCR     1024    /* alloc this much extra when expanding */

/* See if the regions are in the standard order and non-overlapping */
static int ft_ordered(struct ft_cxt *cxt)
{
        char *p = (char *)cxt->bph + HDR_SIZE;
        enum ft_rgn_id r;

        for (r = FT_RSVMAP; r <= FT_STRINGS; ++r) {
                if (p > cxt->rgn[r].start)
                        return 0;
                p = cxt->rgn[r].start + cxt->rgn[r].size;
        }
        return p <= (char *)cxt->bph + cxt->max_size;
}

/* Copy the tree to a newly-allocated region and put things in order */
static int ft_reorder(struct ft_cxt *cxt, int nextra)
{
        unsigned long tot;
        enum ft_rgn_id r;
        char *p, *pend;
        int stroff;

        tot = HDR_SIZE + EXPAND_INCR;
        for (r = FT_RSVMAP; r <= FT_STRINGS; ++r)
                tot += cxt->rgn[r].size;
        if (nextra > 0)
                tot += nextra;
        tot = _ALIGN(tot, 8);

        if (!cxt->realloc)
                return 0;
        p = cxt->realloc(NULL, tot);
        if (!p)
                return 0;

        memcpy(p, cxt->bph, sizeof(struct boot_param_header));
        /* offsets get fixed up later */

        cxt->bph = (struct boot_param_header *)p;
        cxt->max_size = tot;
        pend = p + tot;
        p += HDR_SIZE;

        memcpy(p, cxt->rgn[FT_RSVMAP].start, cxt->rgn[FT_RSVMAP].size);
        cxt->rgn[FT_RSVMAP].start = p;
        p += cxt->rgn[FT_RSVMAP].size;

        memcpy(p, cxt->rgn[FT_STRUCT].start, cxt->rgn[FT_STRUCT].size);
        ft_node_update_after(cxt, cxt->rgn[FT_STRUCT].start,
                        p - cxt->rgn[FT_STRUCT].start);
        cxt->p += p - cxt->rgn[FT_STRUCT].start;
        cxt->rgn[FT_STRUCT].start = p;

        p = pend - cxt->rgn[FT_STRINGS].size;
        memcpy(p, cxt->rgn[FT_STRINGS].start, cxt->rgn[FT_STRINGS].size);
        stroff = cxt->str_anchor - cxt->rgn[FT_STRINGS].start;
        cxt->rgn[FT_STRINGS].start = p;
        cxt->str_anchor = p + stroff;

        cxt->isordered = 1;
        return 1;
}

static inline char *prev_end(struct ft_cxt *cxt, enum ft_rgn_id r)
{
        if (r > FT_RSVMAP)
                return cxt->rgn[r - 1].start + cxt->rgn[r - 1].size;
        return (char *)cxt->bph + HDR_SIZE;
}

static inline char *next_start(struct ft_cxt *cxt, enum ft_rgn_id r)
{
        if (r < FT_STRINGS)
                return cxt->rgn[r + 1].start;
        return (char *)cxt->bph + cxt->max_size;
}

/*
 * See if we can expand region rgn by nextra bytes by using up
 * free space after or before the region.
 */
static int ft_shuffle(struct ft_cxt *cxt, char **pp, enum ft_rgn_id rgn,
                int nextra)
{
        char *p = *pp;
        char *rgn_start, *rgn_end;

        rgn_start = cxt->rgn[rgn].start;
        rgn_end = rgn_start + cxt->rgn[rgn].size;
        if (nextra <= 0 || rgn_end + nextra <= next_start(cxt, rgn)) {
                /* move following stuff */
                if (p < rgn_end) {
                        if (nextra < 0)
                                memmove(p, p - nextra, rgn_end - p + nextra);
                        else
                                memmove(p + nextra, p, rgn_end - p);
                        if (rgn == FT_STRUCT)
                                ft_node_update_after(cxt, p, nextra);
                }
                cxt->rgn[rgn].size += nextra;
                if (rgn == FT_STRINGS)
                        /* assumes strings only added at beginning */
                        cxt->str_anchor += nextra;
                return 1;
        }
        if (prev_end(cxt, rgn) <= rgn_start - nextra) {
                /* move preceding stuff */
                if (p > rgn_start) {
                        memmove(rgn_start - nextra, rgn_start, p - rgn_start);
                        if (rgn == FT_STRUCT)
                                ft_node_update_before(cxt, p, -nextra);
                }
                *pp -= nextra;
                cxt->rgn[rgn].start -= nextra;
                cxt->rgn[rgn].size += nextra;
                return 1;
        }
        return 0;
}

static int ft_make_space(struct ft_cxt *cxt, char **pp, enum ft_rgn_id rgn,
                         int nextra)
{
        unsigned long size, ssize, tot;
        char *str, *next;
        enum ft_rgn_id r;

        if (!cxt->isordered) {
                unsigned long rgn_off = *pp - cxt->rgn[rgn].start;

                if (!ft_reorder(cxt, nextra))
                        return 0;

                *pp = cxt->rgn[rgn].start + rgn_off;
        }
        if (ft_shuffle(cxt, pp, rgn, nextra))
                return 1;

        /* See if there is space after the strings section */
        ssize = cxt->rgn[FT_STRINGS].size;
        if (cxt->rgn[FT_STRINGS].start + ssize
                        < (char *)cxt->bph + cxt->max_size) {
                /* move strings up as far as possible */
                str = (char *)cxt->bph + cxt->max_size - ssize;
                cxt->str_anchor += str - cxt->rgn[FT_STRINGS].start;
                memmove(str, cxt->rgn[FT_STRINGS].start, ssize);
                cxt->rgn[FT_STRINGS].start = str;
                /* enough space now? */
                if (rgn >= FT_STRUCT && ft_shuffle(cxt, pp, rgn, nextra))
                        return 1;
        }

        /* how much total free space is there following this region? */
        tot = 0;
        for (r = rgn; r < FT_STRINGS; ++r) {
                char *r_end = cxt->rgn[r].start + cxt->rgn[r].size;
                tot += next_start(cxt, rgn) - r_end;
        }

        /* cast is to shut gcc up; we know nextra >= 0 */
        if (tot < (unsigned int)nextra) {
                /* have to reallocate */
                char *newp, *new_start;
                int shift;

                if (!cxt->realloc)
                        return 0;
                size = _ALIGN(cxt->max_size + (nextra - tot) + EXPAND_INCR, 8);
                newp = cxt->realloc(cxt->bph, size);
                if (!newp)
                        return 0;
                cxt->max_size = size;
                shift = newp - (char *)cxt->bph;

                if (shift) { /* realloc can return same addr */
                        cxt->bph = (struct boot_param_header *)newp;
                        ft_node_update_after(cxt, cxt->rgn[FT_STRUCT].start,
                                        shift);
                        for (r = FT_RSVMAP; r <= FT_STRINGS; ++r) {
                                new_start = cxt->rgn[r].start + shift;
                                cxt->rgn[r].start = new_start;
                        }
                        *pp += shift;
                        cxt->str_anchor += shift;
                }

                /* move strings up to the end */
                str = newp + size - ssize;
                cxt->str_anchor += str - cxt->rgn[FT_STRINGS].start;
                memmove(str, cxt->rgn[FT_STRINGS].start, ssize);
                cxt->rgn[FT_STRINGS].start = str;

                if (ft_shuffle(cxt, pp, rgn, nextra))
                        return 1;
        }

        /* must be FT_RSVMAP and we need to move FT_STRUCT up */
        if (rgn == FT_RSVMAP) {
                next = cxt->rgn[FT_RSVMAP].start + cxt->rgn[FT_RSVMAP].size
                        + nextra;
                ssize = cxt->rgn[FT_STRUCT].size;
                if (next + ssize >= cxt->rgn[FT_STRINGS].start)
                        return 0;       /* "can't happen" */
                memmove(next, cxt->rgn[FT_STRUCT].start, ssize);
                ft_node_update_after(cxt, cxt->rgn[FT_STRUCT].start, nextra);
                cxt->rgn[FT_STRUCT].start = next;

                if (ft_shuffle(cxt, pp, rgn, nextra))
                        return 1;
        }

        return 0;               /* "can't happen" */
}

static void ft_put_word(struct ft_cxt *cxt, u32 v)
{
        *(u32 *) cxt->p = cpu_to_be32(v);
        cxt->p += 4;
}

static void ft_put_bin(struct ft_cxt *cxt, const void *data, unsigned int sz)
{
        unsigned long sza = _ALIGN(sz, 4);

        /* zero out the alignment gap if necessary */
        if (sz < sza)
                *(u32 *) (cxt->p + sza - 4) = 0;

        /* copy in the data */
        memcpy(cxt->p, data, sz);

        cxt->p += sza;
}

int ft_begin_node(struct ft_cxt *cxt, const char *name)
{
        unsigned long nlen = strlen(name) + 1;
        unsigned long len = 8 + _ALIGN(nlen, 4);

        if (!ft_make_space(cxt, &cxt->p, FT_STRUCT, len))
                return -1;
        ft_put_word(cxt, OF_DT_BEGIN_NODE);
        ft_put_bin(cxt, name, strlen(name) + 1);
        return 0;
}

void ft_end_node(struct ft_cxt *cxt)
{
        ft_put_word(cxt, OF_DT_END_NODE);
}

void ft_nop(struct ft_cxt *cxt)
{
        if (ft_make_space(cxt, &cxt->p, FT_STRUCT, 4))
                ft_put_word(cxt, OF_DT_NOP);
}

#define NO_STRING       0x7fffffff

static int lookup_string(struct ft_cxt *cxt, const char *name)
{
        char *p, *end;

        p = cxt->rgn[FT_STRINGS].start;
        end = p + cxt->rgn[FT_STRINGS].size;
        while (p < end) {
                if (strcmp(p, (char *)name) == 0)
                        return p - cxt->str_anchor;
                p += strlen(p) + 1;
        }

        return NO_STRING;
}

/* lookup string and insert if not found */
static int map_string(struct ft_cxt *cxt, const char *name)
{
        int off;
        char *p;

        off = lookup_string(cxt, name);
        if (off != NO_STRING)
                return off;
        p = cxt->rgn[FT_STRINGS].start;
        if (!ft_make_space(cxt, &p, FT_STRINGS, strlen(name) + 1))
                return NO_STRING;
        strcpy(p, name);
        return p - cxt->str_anchor;
}

int ft_prop(struct ft_cxt *cxt, const char *name, const void *data,
                unsigned int sz)
{
        int off, len;

        off = map_string(cxt, name);
        if (off == NO_STRING)
                return -1;

        len = 12 + _ALIGN(sz, 4);
        if (!ft_make_space(cxt, &cxt->p, FT_STRUCT, len))
                return -1;

        ft_put_word(cxt, OF_DT_PROP);
        ft_put_word(cxt, sz);
        ft_put_word(cxt, off);
        ft_put_bin(cxt, data, sz);
        return 0;
}

int ft_prop_str(struct ft_cxt *cxt, const char *name, const char *str)
{
        return ft_prop(cxt, name, str, strlen(str) + 1);
}

int ft_prop_int(struct ft_cxt *cxt, const char *name, unsigned int val)
{
        u32 v = cpu_to_be32((u32) val);

        return ft_prop(cxt, name, &v, 4);
}

/* Calculate the size of the reserved map */
static unsigned long rsvmap_size(struct ft_cxt *cxt)
{
        struct ft_reserve *res;

        res = (struct ft_reserve *)cxt->rgn[FT_RSVMAP].start;
        while (res->start || res->len)
                ++res;
        return (char *)(res + 1) - cxt->rgn[FT_RSVMAP].start;
}

/* Calculate the size of the struct region by stepping through it */
static unsigned long struct_size(struct ft_cxt *cxt)
{
        char *p = cxt->rgn[FT_STRUCT].start;
        char *next;
        struct ft_atom atom;

        /* make check in ft_next happy */
        if (cxt->rgn[FT_STRUCT].size == 0)
                cxt->rgn[FT_STRUCT].size = 0xfffffffful - (unsigned long)p;

        while ((next = ft_next(cxt, p, &atom)) != NULL)
                p = next;
        return p + 4 - cxt->rgn[FT_STRUCT].start;
}

/* add `adj' on to all string offset values in the struct area */
static void adjust_string_offsets(struct ft_cxt *cxt, int adj)
{
        char *p = cxt->rgn[FT_STRUCT].start;
        char *next;
        struct ft_atom atom;
        int off;

        while ((next = ft_next(cxt, p, &atom)) != NULL) {
                if (atom.tag == OF_DT_PROP) {
                        off = be32_to_cpu(*(u32 *) (p + 8));
                        *(u32 *) (p + 8) = cpu_to_be32(off + adj);
                }
                p = next;
        }
}

/* start construction of the flat OF tree from scratch */
void ft_begin(struct ft_cxt *cxt, void *blob, unsigned int max_size,
                void *(*realloc_fn) (void *, unsigned long))
{
        struct boot_param_header *bph = blob;
        char *p;
        struct ft_reserve *pres;

        /* clear the cxt */
        memset(cxt, 0, sizeof(*cxt));

        cxt->bph = bph;
        cxt->max_size = max_size;
        cxt->realloc = realloc_fn;
        cxt->isordered = 1;

        /* zero everything in the header area */
        memset(bph, 0, sizeof(*bph));

        bph->magic = cpu_to_be32(OF_DT_HEADER);
        bph->version = cpu_to_be32(0x10);
        bph->last_comp_version = cpu_to_be32(0x10);

        /* start pointers */
        cxt->rgn[FT_RSVMAP].start = p = blob + HDR_SIZE;
        cxt->rgn[FT_RSVMAP].size = sizeof(struct ft_reserve);
        pres = (struct ft_reserve *)p;
        cxt->rgn[FT_STRUCT].start = p += sizeof(struct ft_reserve);
        cxt->rgn[FT_STRUCT].size = 4;
        cxt->rgn[FT_STRINGS].start = blob + max_size;
        cxt->rgn[FT_STRINGS].size = 0;

        /* init rsvmap and struct */
        pres->start = 0;
        pres->len = 0;
        *(u32 *) p = cpu_to_be32(OF_DT_END);

        cxt->str_anchor = blob;
}

/* open up an existing blob to be examined or modified */
int ft_open(struct ft_cxt *cxt, void *blob, unsigned int max_size,
                unsigned int max_find_device,
                void *(*realloc_fn) (void *, unsigned long))
{
        struct boot_param_header *bph = blob;

        /* can't cope with version < 16 */
        if (be32_to_cpu(bph->version) < 16)
                return -1;

        /* clear the cxt */
        memset(cxt, 0, sizeof(*cxt));

        /* alloc node_tbl to track node ptrs returned by ft_find_device */
        ++max_find_device;
        cxt->node_tbl = realloc_fn(NULL, max_find_device * sizeof(char *));
        if (!cxt->node_tbl)
                return -1;
        memset(cxt->node_tbl, 0, max_find_device * sizeof(char *));
        cxt->node_max = max_find_device;
        cxt->nodes_used = 1;    /* don't use idx 0 b/c looks like NULL */

        cxt->bph = bph;
        cxt->max_size = max_size;
        cxt->realloc = realloc_fn;

        cxt->rgn[FT_RSVMAP].start = blob + be32_to_cpu(bph->off_mem_rsvmap);
        cxt->rgn[FT_RSVMAP].size = rsvmap_size(cxt);
        cxt->rgn[FT_STRUCT].start = blob + be32_to_cpu(bph->off_dt_struct);
        cxt->rgn[FT_STRUCT].size = struct_size(cxt);
        cxt->rgn[FT_STRINGS].start = blob + be32_to_cpu(bph->off_dt_strings);
        cxt->rgn[FT_STRINGS].size = be32_to_cpu(bph->dt_strings_size);
        /* Leave as '0' to force first ft_make_space call to do a ft_reorder
         * and move dt to an area allocated by realloc.
        cxt->isordered = ft_ordered(cxt);
        */

        cxt->p = cxt->rgn[FT_STRUCT].start;
        cxt->str_anchor = cxt->rgn[FT_STRINGS].start;

        return 0;
}

/* add a reserver physical area to the rsvmap */
int ft_add_rsvmap(struct ft_cxt *cxt, u64 physaddr, u64 size)
{
        char *p;
        struct ft_reserve *pres;

        p = cxt->rgn[FT_RSVMAP].start + cxt->rgn[FT_RSVMAP].size
                - sizeof(struct ft_reserve);
        if (!ft_make_space(cxt, &p, FT_RSVMAP, sizeof(struct ft_reserve)))
                return -1;

        pres = (struct ft_reserve *)p;
        pres->start = cpu_to_be64(physaddr);
        pres->len = cpu_to_be64(size);

        return 0;
}

void ft_begin_tree(struct ft_cxt *cxt)
{
        cxt->p = ft_root_node(cxt);
}

void ft_end_tree(struct ft_cxt *cxt)
{
        struct boot_param_header *bph = cxt->bph;
        char *p, *oldstr, *str, *endp;
        unsigned long ssize;
        int adj;

        if (!cxt->isordered)
                return;         /* we haven't touched anything */

        /* adjust string offsets */
        oldstr = cxt->rgn[FT_STRINGS].start;
        adj = cxt->str_anchor - oldstr;
        if (adj)
                adjust_string_offsets(cxt, adj);

        /* make strings end on 8-byte boundary */
        ssize = cxt->rgn[FT_STRINGS].size;
        endp = (char *)_ALIGN((unsigned long)cxt->rgn[FT_STRUCT].start
                        + cxt->rgn[FT_STRUCT].size + ssize, 8);
        str = endp - ssize;

        /* move strings down to end of structs */
        memmove(str, oldstr, ssize);
        cxt->str_anchor = str;
        cxt->rgn[FT_STRINGS].start = str;

        /* fill in header fields */
        p = (char *)bph;
        bph->totalsize = cpu_to_be32(endp - p);
        bph->off_mem_rsvmap = cpu_to_be32(cxt->rgn[FT_RSVMAP].start - p);
        bph->off_dt_struct = cpu_to_be32(cxt->rgn[FT_STRUCT].start - p);
        bph->off_dt_strings = cpu_to_be32(cxt->rgn[FT_STRINGS].start - p);
        bph->dt_strings_size = cpu_to_be32(ssize);
}

void *ft_find_device(struct ft_cxt *cxt, const char *srch_path)
{
        char *node;

        /* require absolute path */
        if (srch_path[0] != '/')
                return NULL;
        node = ft_find_descendent(cxt, ft_root_node(cxt), srch_path);
        return ft_get_phandle(cxt, node);
}

void *ft_find_device_rel(struct ft_cxt *cxt, const void *top,
                         const char *srch_path)
{
        char *node;

        node = ft_node_ph2node(cxt, top);
        if (node == NULL)
                return NULL;

        node = ft_find_descendent(cxt, node, srch_path);
        return ft_get_phandle(cxt, node);
}

void *ft_find_descendent(struct ft_cxt *cxt, void *top, const char *srch_path)
{
        struct ft_atom atom;
        char *p;
        const char *cp, *q;
        int cl;
        int depth = -1;
        int dmatch = 0;
        const char *path_comp[FT_MAX_DEPTH];

        cp = srch_path;
        cl = 0;
        p = top;

        while ((p = ft_next(cxt, p, &atom)) != NULL) {
                switch (atom.tag) {
                case OF_DT_BEGIN_NODE:
                        ++depth;
                        if (depth != dmatch)
                                break;
                        cxt->genealogy[depth] = atom.data;
                        cxt->genealogy[depth + 1] = NULL;
                        if (depth && !(strncmp(atom.name, cp, cl) == 0
                                        && (atom.name[cl] == '/'
                                                || atom.name[cl] == '\0'
                                                || atom.name[cl] == '@')))
                                break;
                        path_comp[dmatch] = cp;
                        /* it matches so far, advance to next path component */
                        cp += cl;
                        /* skip slashes */
                        while (*cp == '/')
                                ++cp;
                        /* we're done if this is the end of the string */
                        if (*cp == 0)
                                return atom.data;
                        /* look for end of this component */
                        q = strchr(cp, '/');
                        if (q)
                                cl = q - cp;
                        else
                                cl = strlen(cp);
                        ++dmatch;
                        break;
                case OF_DT_END_NODE:
                        if (depth == 0)
                                return NULL;
                        if (dmatch > depth) {
                                --dmatch;
                                cl = cp - path_comp[dmatch] - 1;
                                cp = path_comp[dmatch];
                                while (cl > 0 && cp[cl - 1] == '/')
                                        --cl;
                        }
                        --depth;
                        break;
                }
        }
        return NULL;
}

void *__ft_get_parent(struct ft_cxt *cxt, void *node)
{
        int d;
        struct ft_atom atom;
        char *p;

        for (d = 0; cxt->genealogy[d] != NULL; ++d)
                if (cxt->genealogy[d] == node)
                        return d > 0 ? cxt->genealogy[d - 1] : NULL;

        /* have to do it the hard way... */
        p = ft_root_node(cxt);
        d = 0;
        while ((p = ft_next(cxt, p, &atom)) != NULL) {
                switch (atom.tag) {
                case OF_DT_BEGIN_NODE:
                        cxt->genealogy[d] = atom.data;
                        if (node == atom.data) {
                                /* found it */
                                cxt->genealogy[d + 1] = NULL;
                                return d > 0 ? cxt->genealogy[d - 1] : NULL;
                        }
                        ++d;
                        break;
                case OF_DT_END_NODE:
                        --d;
                        break;
                }
        }
        return NULL;
}

void *ft_get_parent(struct ft_cxt *cxt, const void *phandle)
{
        void *node = ft_node_ph2node(cxt, phandle);
        if (node == NULL)
                return NULL;

        node = __ft_get_parent(cxt, node);
        return ft_get_phandle(cxt, node);
}

static const void *__ft_get_prop(struct ft_cxt *cxt, void *node,
                                 const char *propname, unsigned int *len)
{
        struct ft_atom atom;
        int depth = 0;

        while ((node = ft_next(cxt, node, &atom)) != NULL) {
                switch (atom.tag) {
                case OF_DT_BEGIN_NODE:
                        ++depth;
                        break;

                case OF_DT_PROP:
                        if (depth != 1 || strcmp(atom.name, propname))
                                break;

                        if (len)
                                *len = atom.size;

                        return atom.data;

                case OF_DT_END_NODE:
                        if (--depth <= 0)
                                return NULL;
                }
        }

        return NULL;
}

int ft_get_prop(struct ft_cxt *cxt, const void *phandle, const char *propname,
                void *buf, const unsigned int buflen)
{
        const void *data;
        unsigned int size;

        void *node = ft_node_ph2node(cxt, phandle);
        if (!node)
                return -1;

        data = __ft_get_prop(cxt, node, propname, &size);
        if (data) {
                unsigned int clipped_size = min(size, buflen);
                memcpy(buf, data, clipped_size);
                return size;
        }

        return -1;
}

void *__ft_find_node_by_prop_value(struct ft_cxt *cxt, void *prev,
                                   const char *propname, const char *propval,
                                   unsigned int proplen)
{
        struct ft_atom atom;
        char *p = ft_root_node(cxt);
        char *next;
        int past_prev = prev ? 0 : 1;
        int depth = -1;

        while ((next = ft_next(cxt, p, &atom)) != NULL) {
                const void *data;
                unsigned int size;

                switch (atom.tag) {
                case OF_DT_BEGIN_NODE:
                        depth++;

                        if (prev == p) {
                                past_prev = 1;
                                break;
                        }

                        if (!past_prev || depth < 1)
                                break;

                        data = __ft_get_prop(cxt, p, propname, &size);
                        if (!data || size != proplen)
                                break;
                        if (memcmp(data, propval, size))
                                break;

                        return p;

                case OF_DT_END_NODE:
                        if (depth-- == 0)
                                return NULL;

                        break;
                }

                p = next;
        }

        return NULL;
}

void *ft_find_node_by_prop_value(struct ft_cxt *cxt, const void *prev,
                                 const char *propname, const char *propval,
                                 int proplen)
{
        void *node = NULL;

        if (prev) {
                node = ft_node_ph2node(cxt, prev);

                if (!node)
                        return NULL;
        }

        node = __ft_find_node_by_prop_value(cxt, node, propname,
                                            propval, proplen);
        return ft_get_phandle(cxt, node);
}

int ft_set_prop(struct ft_cxt *cxt, const void *phandle, const char *propname,
                const void *buf, const unsigned int buflen)
{
        struct ft_atom atom;
        void *node;
        char *p, *next;
        int nextra;

        node = ft_node_ph2node(cxt, phandle);
        if (node == NULL)
                return -1;

        next = ft_next(cxt, node, &atom);
        if (atom.tag != OF_DT_BEGIN_NODE)
                /* phandle didn't point to a node */
                return -1;
        p = next;

        while ((next = ft_next(cxt, p, &atom)) != NULL) {
                switch (atom.tag) {
                case OF_DT_BEGIN_NODE: /* properties must go before subnodes */
                case OF_DT_END_NODE:
                        /* haven't found the property, insert here */
                        cxt->p = p;
                        return ft_prop(cxt, propname, buf, buflen);
                case OF_DT_PROP:
                        if (strcmp(atom.name, propname))
                                break;
                        /* found an existing property, overwrite it */
                        nextra = _ALIGN(buflen, 4) - _ALIGN(atom.size, 4);
                        cxt->p = atom.data;
                        if (nextra && !ft_make_space(cxt, &cxt->p, FT_STRUCT,
                                                nextra))
                                return -1;
                        *(u32 *) (cxt->p - 8) = cpu_to_be32(buflen);
                        ft_put_bin(cxt, buf, buflen);
                        return 0;
                }
                p = next;
        }
        return -1;
}

int ft_del_prop(struct ft_cxt *cxt, const void *phandle, const char *propname)
{
        struct ft_atom atom;
        void *node;
        char *p, *next;
        int size;

        node = ft_node_ph2node(cxt, phandle);
        if (node == NULL)
                return -1;

        p = node;
        while ((next = ft_next(cxt, p, &atom)) != NULL) {
                switch (atom.tag) {
                case OF_DT_BEGIN_NODE:
                case OF_DT_END_NODE:
                        return -1;
                case OF_DT_PROP:
                        if (strcmp(atom.name, propname))
                                break;
                        /* found the property, remove it */
                        size = 12 + -_ALIGN(atom.size, 4);
                        cxt->p = p;
                        if (!ft_make_space(cxt, &cxt->p, FT_STRUCT, -size))
                                return -1;
                        return 0;
                }
                p = next;
        }
        return -1;
}

void *ft_create_node(struct ft_cxt *cxt, const void *parent, const char *name)
{
        struct ft_atom atom;
        char *p, *next;
        int depth = 0;

        if (parent) {
                p = ft_node_ph2node(cxt, parent);
                if (!p)
                        return NULL;
        } else {
                p = ft_root_node(cxt);
        }

        while ((next = ft_next(cxt, p, &atom)) != NULL) {
                switch (atom.tag) {
                case OF_DT_BEGIN_NODE:
                        ++depth;
                        if (depth == 1 && strcmp(atom.name, name) == 0)
                                /* duplicate node name, return error */
                                return NULL;
                        break;
                case OF_DT_END_NODE:
                        --depth;
                        if (depth > 0)
                                break;
                        /* end of node, insert here */
                        cxt->p = p;
                        ft_begin_node(cxt, name);
                        ft_end_node(cxt);
                        return p;
                }
                p = next;
        }
        return NULL;
}