Add qemu 2.4.0
[kvmfornfv.git] / qemu / dtc / flattree.c
diff --git a/qemu/dtc/flattree.c b/qemu/dtc/flattree.c
new file mode 100644 (file)
index 0000000..665dad7
--- /dev/null
@@ -0,0 +1,933 @@
+/*
+ * (C) Copyright David Gibson <dwg@au1.ibm.com>, IBM Corporation.  2005.
+ *
+ *
+ * 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, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
+ *                                                                   USA
+ */
+
+#include "dtc.h"
+#include "srcpos.h"
+
+#define FTF_FULLPATH   0x1
+#define FTF_VARALIGN   0x2
+#define FTF_NAMEPROPS  0x4
+#define FTF_BOOTCPUID  0x8
+#define FTF_STRTABSIZE 0x10
+#define FTF_STRUCTSIZE 0x20
+#define FTF_NOPS       0x40
+
+static struct version_info {
+       int version;
+       int last_comp_version;
+       int hdr_size;
+       int flags;
+} version_table[] = {
+       {1, 1, FDT_V1_SIZE,
+        FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS},
+       {2, 1, FDT_V2_SIZE,
+        FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS|FTF_BOOTCPUID},
+       {3, 1, FDT_V3_SIZE,
+        FTF_FULLPATH|FTF_VARALIGN|FTF_NAMEPROPS|FTF_BOOTCPUID|FTF_STRTABSIZE},
+       {16, 16, FDT_V3_SIZE,
+        FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_NOPS},
+       {17, 16, FDT_V17_SIZE,
+        FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS},
+};
+
+struct emitter {
+       void (*cell)(void *, cell_t);
+       void (*string)(void *, char *, int);
+       void (*align)(void *, int);
+       void (*data)(void *, struct data);
+       void (*beginnode)(void *, struct label *labels);
+       void (*endnode)(void *, struct label *labels);
+       void (*property)(void *, struct label *labels);
+};
+
+static void bin_emit_cell(void *e, cell_t val)
+{
+       struct data *dtbuf = e;
+
+       *dtbuf = data_append_cell(*dtbuf, val);
+}
+
+static void bin_emit_string(void *e, char *str, int len)
+{
+       struct data *dtbuf = e;
+
+       if (len == 0)
+               len = strlen(str);
+
+       *dtbuf = data_append_data(*dtbuf, str, len);
+       *dtbuf = data_append_byte(*dtbuf, '\0');
+}
+
+static void bin_emit_align(void *e, int a)
+{
+       struct data *dtbuf = e;
+
+       *dtbuf = data_append_align(*dtbuf, a);
+}
+
+static void bin_emit_data(void *e, struct data d)
+{
+       struct data *dtbuf = e;
+
+       *dtbuf = data_append_data(*dtbuf, d.val, d.len);
+}
+
+static void bin_emit_beginnode(void *e, struct label *labels)
+{
+       bin_emit_cell(e, FDT_BEGIN_NODE);
+}
+
+static void bin_emit_endnode(void *e, struct label *labels)
+{
+       bin_emit_cell(e, FDT_END_NODE);
+}
+
+static void bin_emit_property(void *e, struct label *labels)
+{
+       bin_emit_cell(e, FDT_PROP);
+}
+
+static struct emitter bin_emitter = {
+       .cell = bin_emit_cell,
+       .string = bin_emit_string,
+       .align = bin_emit_align,
+       .data = bin_emit_data,
+       .beginnode = bin_emit_beginnode,
+       .endnode = bin_emit_endnode,
+       .property = bin_emit_property,
+};
+
+static void emit_label(FILE *f, const char *prefix, const char *label)
+{
+       fprintf(f, "\t.globl\t%s_%s\n", prefix, label);
+       fprintf(f, "%s_%s:\n", prefix, label);
+       fprintf(f, "_%s_%s:\n", prefix, label);
+}
+
+static void emit_offset_label(FILE *f, const char *label, int offset)
+{
+       fprintf(f, "\t.globl\t%s\n", label);
+       fprintf(f, "%s\t= . + %d\n", label, offset);
+}
+
+#define ASM_EMIT_BELONG(f, fmt, ...) \
+       { \
+               fprintf((f), "\t.byte\t((" fmt ") >> 24) & 0xff\n", __VA_ARGS__); \
+               fprintf((f), "\t.byte\t((" fmt ") >> 16) & 0xff\n", __VA_ARGS__); \
+               fprintf((f), "\t.byte\t((" fmt ") >> 8) & 0xff\n", __VA_ARGS__); \
+               fprintf((f), "\t.byte\t(" fmt ") & 0xff\n", __VA_ARGS__); \
+       }
+
+static void asm_emit_cell(void *e, cell_t val)
+{
+       FILE *f = e;
+
+       fprintf(f, "\t.byte 0x%02x; .byte 0x%02x; .byte 0x%02x; .byte 0x%02x\n",
+               (val >> 24) & 0xff, (val >> 16) & 0xff,
+               (val >> 8) & 0xff, val & 0xff);
+}
+
+static void asm_emit_string(void *e, char *str, int len)
+{
+       FILE *f = e;
+       char c = 0;
+
+       if (len != 0) {
+               /* XXX: ewww */
+               c = str[len];
+               str[len] = '\0';
+       }
+
+       fprintf(f, "\t.string\t\"%s\"\n", str);
+
+       if (len != 0) {
+               str[len] = c;
+       }
+}
+
+static void asm_emit_align(void *e, int a)
+{
+       FILE *f = e;
+
+       fprintf(f, "\t.balign\t%d, 0\n", a);
+}
+
+static void asm_emit_data(void *e, struct data d)
+{
+       FILE *f = e;
+       int off = 0;
+       struct marker *m = d.markers;
+
+       for_each_marker_of_type(m, LABEL)
+               emit_offset_label(f, m->ref, m->offset);
+
+       while ((d.len - off) >= sizeof(uint32_t)) {
+               asm_emit_cell(e, fdt32_to_cpu(*((uint32_t *)(d.val+off))));
+               off += sizeof(uint32_t);
+       }
+
+       while ((d.len - off) >= 1) {
+               fprintf(f, "\t.byte\t0x%hhx\n", d.val[off]);
+               off += 1;
+       }
+
+       assert(off == d.len);
+}
+
+static void asm_emit_beginnode(void *e, struct label *labels)
+{
+       FILE *f = e;
+       struct label *l;
+
+       for_each_label(labels, l) {
+               fprintf(f, "\t.globl\t%s\n", l->label);
+               fprintf(f, "%s:\n", l->label);
+       }
+       fprintf(f, "\t/* FDT_BEGIN_NODE */\n");
+       asm_emit_cell(e, FDT_BEGIN_NODE);
+}
+
+static void asm_emit_endnode(void *e, struct label *labels)
+{
+       FILE *f = e;
+       struct label *l;
+
+       fprintf(f, "\t/* FDT_END_NODE */\n");
+       asm_emit_cell(e, FDT_END_NODE);
+       for_each_label(labels, l) {
+               fprintf(f, "\t.globl\t%s_end\n", l->label);
+               fprintf(f, "%s_end:\n", l->label);
+       }
+}
+
+static void asm_emit_property(void *e, struct label *labels)
+{
+       FILE *f = e;
+       struct label *l;
+
+       for_each_label(labels, l) {
+               fprintf(f, "\t.globl\t%s\n", l->label);
+               fprintf(f, "%s:\n", l->label);
+       }
+       fprintf(f, "\t/* FDT_PROP */\n");
+       asm_emit_cell(e, FDT_PROP);
+}
+
+static struct emitter asm_emitter = {
+       .cell = asm_emit_cell,
+       .string = asm_emit_string,
+       .align = asm_emit_align,
+       .data = asm_emit_data,
+       .beginnode = asm_emit_beginnode,
+       .endnode = asm_emit_endnode,
+       .property = asm_emit_property,
+};
+
+static int stringtable_insert(struct data *d, const char *str)
+{
+       int i;
+
+       /* FIXME: do this more efficiently? */
+
+       for (i = 0; i < d->len; i++) {
+               if (streq(str, d->val + i))
+                       return i;
+       }
+
+       *d = data_append_data(*d, str, strlen(str)+1);
+       return i;
+}
+
+static void flatten_tree(struct node *tree, struct emitter *emit,
+                        void *etarget, struct data *strbuf,
+                        struct version_info *vi)
+{
+       struct property *prop;
+       struct node *child;
+       int seen_name_prop = 0;
+
+       if (tree->deleted)
+               return;
+
+       emit->beginnode(etarget, tree->labels);
+
+       if (vi->flags & FTF_FULLPATH)
+               emit->string(etarget, tree->fullpath, 0);
+       else
+               emit->string(etarget, tree->name, 0);
+
+       emit->align(etarget, sizeof(cell_t));
+
+       for_each_property(tree, prop) {
+               int nameoff;
+
+               if (streq(prop->name, "name"))
+                       seen_name_prop = 1;
+
+               nameoff = stringtable_insert(strbuf, prop->name);
+
+               emit->property(etarget, prop->labels);
+               emit->cell(etarget, prop->val.len);
+               emit->cell(etarget, nameoff);
+
+               if ((vi->flags & FTF_VARALIGN) && (prop->val.len >= 8))
+                       emit->align(etarget, 8);
+
+               emit->data(etarget, prop->val);
+               emit->align(etarget, sizeof(cell_t));
+       }
+
+       if ((vi->flags & FTF_NAMEPROPS) && !seen_name_prop) {
+               emit->property(etarget, NULL);
+               emit->cell(etarget, tree->basenamelen+1);
+               emit->cell(etarget, stringtable_insert(strbuf, "name"));
+
+               if ((vi->flags & FTF_VARALIGN) && ((tree->basenamelen+1) >= 8))
+                       emit->align(etarget, 8);
+
+               emit->string(etarget, tree->name, tree->basenamelen);
+               emit->align(etarget, sizeof(cell_t));
+       }
+
+       for_each_child(tree, child) {
+               flatten_tree(child, emit, etarget, strbuf, vi);
+       }
+
+       emit->endnode(etarget, tree->labels);
+}
+
+static struct data flatten_reserve_list(struct reserve_info *reservelist,
+                                struct version_info *vi)
+{
+       struct reserve_info *re;
+       struct data d = empty_data;
+       static struct fdt_reserve_entry null_re = {0,0};
+       int    j;
+
+       for (re = reservelist; re; re = re->next) {
+               d = data_append_re(d, &re->re);
+       }
+       /*
+        * Add additional reserved slots if the user asked for them.
+        */
+       for (j = 0; j < reservenum; j++) {
+               d = data_append_re(d, &null_re);
+       }
+
+       return d;
+}
+
+static void make_fdt_header(struct fdt_header *fdt,
+                           struct version_info *vi,
+                           int reservesize, int dtsize, int strsize,
+                           int boot_cpuid_phys)
+{
+       int reserve_off;
+
+       reservesize += sizeof(struct fdt_reserve_entry);
+
+       memset(fdt, 0xff, sizeof(*fdt));
+
+       fdt->magic = cpu_to_fdt32(FDT_MAGIC);
+       fdt->version = cpu_to_fdt32(vi->version);
+       fdt->last_comp_version = cpu_to_fdt32(vi->last_comp_version);
+
+       /* Reserve map should be doubleword aligned */
+       reserve_off = ALIGN(vi->hdr_size, 8);
+
+       fdt->off_mem_rsvmap = cpu_to_fdt32(reserve_off);
+       fdt->off_dt_struct = cpu_to_fdt32(reserve_off + reservesize);
+       fdt->off_dt_strings = cpu_to_fdt32(reserve_off + reservesize
+                                         + dtsize);
+       fdt->totalsize = cpu_to_fdt32(reserve_off + reservesize + dtsize + strsize);
+
+       if (vi->flags & FTF_BOOTCPUID)
+               fdt->boot_cpuid_phys = cpu_to_fdt32(boot_cpuid_phys);
+       if (vi->flags & FTF_STRTABSIZE)
+               fdt->size_dt_strings = cpu_to_fdt32(strsize);
+       if (vi->flags & FTF_STRUCTSIZE)
+               fdt->size_dt_struct = cpu_to_fdt32(dtsize);
+}
+
+void dt_to_blob(FILE *f, struct boot_info *bi, int version)
+{
+       struct version_info *vi = NULL;
+       int i;
+       struct data blob       = empty_data;
+       struct data reservebuf = empty_data;
+       struct data dtbuf      = empty_data;
+       struct data strbuf     = empty_data;
+       struct fdt_header fdt;
+       int padlen = 0;
+
+       for (i = 0; i < ARRAY_SIZE(version_table); i++) {
+               if (version_table[i].version == version)
+                       vi = &version_table[i];
+       }
+       if (!vi)
+               die("Unknown device tree blob version %d\n", version);
+
+       flatten_tree(bi->dt, &bin_emitter, &dtbuf, &strbuf, vi);
+       bin_emit_cell(&dtbuf, FDT_END);
+
+       reservebuf = flatten_reserve_list(bi->reservelist, vi);
+
+       /* Make header */
+       make_fdt_header(&fdt, vi, reservebuf.len, dtbuf.len, strbuf.len,
+                       bi->boot_cpuid_phys);
+
+       /*
+        * If the user asked for more space than is used, adjust the totalsize.
+        */
+       if (minsize > 0) {
+               padlen = minsize - fdt32_to_cpu(fdt.totalsize);
+               if ((padlen < 0) && (quiet < 1))
+                       fprintf(stderr,
+                               "Warning: blob size %d >= minimum size %d\n",
+                               fdt32_to_cpu(fdt.totalsize), minsize);
+       }
+
+       if (padsize > 0)
+               padlen = padsize;
+
+       if (padlen > 0) {
+               int tsize = fdt32_to_cpu(fdt.totalsize);
+               tsize += padlen;
+               fdt.totalsize = cpu_to_fdt32(tsize);
+       }
+
+       /*
+        * Assemble the blob: start with the header, add with alignment
+        * the reserve buffer, add the reserve map terminating zeroes,
+        * the device tree itself, and finally the strings.
+        */
+       blob = data_append_data(blob, &fdt, vi->hdr_size);
+       blob = data_append_align(blob, 8);
+       blob = data_merge(blob, reservebuf);
+       blob = data_append_zeroes(blob, sizeof(struct fdt_reserve_entry));
+       blob = data_merge(blob, dtbuf);
+       blob = data_merge(blob, strbuf);
+
+       /*
+        * If the user asked for more space than is used, pad out the blob.
+        */
+       if (padlen > 0)
+               blob = data_append_zeroes(blob, padlen);
+
+       if (fwrite(blob.val, blob.len, 1, f) != 1) {
+               if (ferror(f))
+                       die("Error writing device tree blob: %s\n",
+                           strerror(errno));
+               else
+                       die("Short write on device tree blob\n");
+       }
+
+       /*
+        * data_merge() frees the right-hand element so only the blob
+        * remains to be freed.
+        */
+       data_free(blob);
+}
+
+static void dump_stringtable_asm(FILE *f, struct data strbuf)
+{
+       const char *p;
+       int len;
+
+       p = strbuf.val;
+
+       while (p < (strbuf.val + strbuf.len)) {
+               len = strlen(p);
+               fprintf(f, "\t.string \"%s\"\n", p);
+               p += len+1;
+       }
+}
+
+void dt_to_asm(FILE *f, struct boot_info *bi, int version)
+{
+       struct version_info *vi = NULL;
+       int i;
+       struct data strbuf = empty_data;
+       struct reserve_info *re;
+       const char *symprefix = "dt";
+
+       for (i = 0; i < ARRAY_SIZE(version_table); i++) {
+               if (version_table[i].version == version)
+                       vi = &version_table[i];
+       }
+       if (!vi)
+               die("Unknown device tree blob version %d\n", version);
+
+       fprintf(f, "/* autogenerated by dtc, do not edit */\n\n");
+
+       emit_label(f, symprefix, "blob_start");
+       emit_label(f, symprefix, "header");
+       fprintf(f, "\t/* magic */\n");
+       asm_emit_cell(f, FDT_MAGIC);
+       fprintf(f, "\t/* totalsize */\n");
+       ASM_EMIT_BELONG(f, "_%s_blob_abs_end - _%s_blob_start",
+                       symprefix, symprefix);
+       fprintf(f, "\t/* off_dt_struct */\n");
+       ASM_EMIT_BELONG(f, "_%s_struct_start - _%s_blob_start",
+               symprefix, symprefix);
+       fprintf(f, "\t/* off_dt_strings */\n");
+       ASM_EMIT_BELONG(f, "_%s_strings_start - _%s_blob_start",
+               symprefix, symprefix);
+       fprintf(f, "\t/* off_mem_rsvmap */\n");
+       ASM_EMIT_BELONG(f, "_%s_reserve_map - _%s_blob_start",
+               symprefix, symprefix);
+       fprintf(f, "\t/* version */\n");
+       asm_emit_cell(f, vi->version);
+       fprintf(f, "\t/* last_comp_version */\n");
+       asm_emit_cell(f, vi->last_comp_version);
+
+       if (vi->flags & FTF_BOOTCPUID) {
+               fprintf(f, "\t/* boot_cpuid_phys */\n");
+               asm_emit_cell(f, bi->boot_cpuid_phys);
+       }
+
+       if (vi->flags & FTF_STRTABSIZE) {
+               fprintf(f, "\t/* size_dt_strings */\n");
+               ASM_EMIT_BELONG(f, "_%s_strings_end - _%s_strings_start",
+                               symprefix, symprefix);
+       }
+
+       if (vi->flags & FTF_STRUCTSIZE) {
+               fprintf(f, "\t/* size_dt_struct */\n");
+               ASM_EMIT_BELONG(f, "_%s_struct_end - _%s_struct_start",
+                       symprefix, symprefix);
+       }
+
+       /*
+        * Reserve map entries.
+        * Align the reserve map to a doubleword boundary.
+        * Each entry is an (address, size) pair of u64 values.
+        * Always supply a zero-sized temination entry.
+        */
+       asm_emit_align(f, 8);
+       emit_label(f, symprefix, "reserve_map");
+
+       fprintf(f, "/* Memory reserve map from source file */\n");
+
+       /*
+        * Use .long on high and low halfs of u64s to avoid .quad
+        * as it appears .quad isn't available in some assemblers.
+        */
+       for (re = bi->reservelist; re; re = re->next) {
+               struct label *l;
+
+               for_each_label(re->labels, l) {
+                       fprintf(f, "\t.globl\t%s\n", l->label);
+                       fprintf(f, "%s:\n", l->label);
+               }
+               ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.address >> 32));
+               ASM_EMIT_BELONG(f, "0x%08x",
+                               (unsigned int)(re->re.address & 0xffffffff));
+               ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.size >> 32));
+               ASM_EMIT_BELONG(f, "0x%08x", (unsigned int)(re->re.size & 0xffffffff));
+       }
+       for (i = 0; i < reservenum; i++) {
+               fprintf(f, "\t.long\t0, 0\n\t.long\t0, 0\n");
+       }
+
+       fprintf(f, "\t.long\t0, 0\n\t.long\t0, 0\n");
+
+       emit_label(f, symprefix, "struct_start");
+       flatten_tree(bi->dt, &asm_emitter, f, &strbuf, vi);
+
+       fprintf(f, "\t/* FDT_END */\n");
+       asm_emit_cell(f, FDT_END);
+       emit_label(f, symprefix, "struct_end");
+
+       emit_label(f, symprefix, "strings_start");
+       dump_stringtable_asm(f, strbuf);
+       emit_label(f, symprefix, "strings_end");
+
+       emit_label(f, symprefix, "blob_end");
+
+       /*
+        * If the user asked for more space than is used, pad it out.
+        */
+       if (minsize > 0) {
+               fprintf(f, "\t.space\t%d - (_%s_blob_end - _%s_blob_start), 0\n",
+                       minsize, symprefix, symprefix);
+       }
+       if (padsize > 0) {
+               fprintf(f, "\t.space\t%d, 0\n", padsize);
+       }
+       emit_label(f, symprefix, "blob_abs_end");
+
+       data_free(strbuf);
+}
+
+struct inbuf {
+       char *base, *limit, *ptr;
+};
+
+static void inbuf_init(struct inbuf *inb, void *base, void *limit)
+{
+       inb->base = base;
+       inb->limit = limit;
+       inb->ptr = inb->base;
+}
+
+static void flat_read_chunk(struct inbuf *inb, void *p, int len)
+{
+       if ((inb->ptr + len) > inb->limit)
+               die("Premature end of data parsing flat device tree\n");
+
+       memcpy(p, inb->ptr, len);
+
+       inb->ptr += len;
+}
+
+static uint32_t flat_read_word(struct inbuf *inb)
+{
+       uint32_t val;
+
+       assert(((inb->ptr - inb->base) % sizeof(val)) == 0);
+
+       flat_read_chunk(inb, &val, sizeof(val));
+
+       return fdt32_to_cpu(val);
+}
+
+static void flat_realign(struct inbuf *inb, int align)
+{
+       int off = inb->ptr - inb->base;
+
+       inb->ptr = inb->base + ALIGN(off, align);
+       if (inb->ptr > inb->limit)
+               die("Premature end of data parsing flat device tree\n");
+}
+
+static char *flat_read_string(struct inbuf *inb)
+{
+       int len = 0;
+       const char *p = inb->ptr;
+       char *str;
+
+       do {
+               if (p >= inb->limit)
+                       die("Premature end of data parsing flat device tree\n");
+               len++;
+       } while ((*p++) != '\0');
+
+       str = xstrdup(inb->ptr);
+
+       inb->ptr += len;
+
+       flat_realign(inb, sizeof(uint32_t));
+
+       return str;
+}
+
+static struct data flat_read_data(struct inbuf *inb, int len)
+{
+       struct data d = empty_data;
+
+       if (len == 0)
+               return empty_data;
+
+       d = data_grow_for(d, len);
+       d.len = len;
+
+       flat_read_chunk(inb, d.val, len);
+
+       flat_realign(inb, sizeof(uint32_t));
+
+       return d;
+}
+
+static char *flat_read_stringtable(struct inbuf *inb, int offset)
+{
+       const char *p;
+
+       p = inb->base + offset;
+       while (1) {
+               if (p >= inb->limit || p < inb->base)
+                       die("String offset %d overruns string table\n",
+                           offset);
+
+               if (*p == '\0')
+                       break;
+
+               p++;
+       }
+
+       return xstrdup(inb->base + offset);
+}
+
+static struct property *flat_read_property(struct inbuf *dtbuf,
+                                          struct inbuf *strbuf, int flags)
+{
+       uint32_t proplen, stroff;
+       char *name;
+       struct data val;
+
+       proplen = flat_read_word(dtbuf);
+       stroff = flat_read_word(dtbuf);
+
+       name = flat_read_stringtable(strbuf, stroff);
+
+       if ((flags & FTF_VARALIGN) && (proplen >= 8))
+               flat_realign(dtbuf, 8);
+
+       val = flat_read_data(dtbuf, proplen);
+
+       return build_property(name, val);
+}
+
+
+static struct reserve_info *flat_read_mem_reserve(struct inbuf *inb)
+{
+       struct reserve_info *reservelist = NULL;
+       struct reserve_info *new;
+       struct fdt_reserve_entry re;
+
+       /*
+        * Each entry is a pair of u64 (addr, size) values for 4 cell_t's.
+        * List terminates at an entry with size equal to zero.
+        *
+        * First pass, count entries.
+        */
+       while (1) {
+               flat_read_chunk(inb, &re, sizeof(re));
+               re.address  = fdt64_to_cpu(re.address);
+               re.size = fdt64_to_cpu(re.size);
+               if (re.size == 0)
+                       break;
+
+               new = build_reserve_entry(re.address, re.size);
+               reservelist = add_reserve_entry(reservelist, new);
+       }
+
+       return reservelist;
+}
+
+
+static char *nodename_from_path(const char *ppath, const char *cpath)
+{
+       int plen;
+
+       plen = strlen(ppath);
+
+       if (!strneq(ppath, cpath, plen))
+               die("Path \"%s\" is not valid as a child of \"%s\"\n",
+                   cpath, ppath);
+
+       /* root node is a special case */
+       if (!streq(ppath, "/"))
+               plen++;
+
+       return xstrdup(cpath + plen);
+}
+
+static struct node *unflatten_tree(struct inbuf *dtbuf,
+                                  struct inbuf *strbuf,
+                                  const char *parent_flatname, int flags)
+{
+       struct node *node;
+       char *flatname;
+       uint32_t val;
+
+       node = build_node(NULL, NULL);
+
+       flatname = flat_read_string(dtbuf);
+
+       if (flags & FTF_FULLPATH)
+               node->name = nodename_from_path(parent_flatname, flatname);
+       else
+               node->name = flatname;
+
+       do {
+               struct property *prop;
+               struct node *child;
+
+               val = flat_read_word(dtbuf);
+               switch (val) {
+               case FDT_PROP:
+                       if (node->children)
+                               fprintf(stderr, "Warning: Flat tree input has "
+                                       "subnodes preceding a property.\n");
+                       prop = flat_read_property(dtbuf, strbuf, flags);
+                       add_property(node, prop);
+                       break;
+
+               case FDT_BEGIN_NODE:
+                       child = unflatten_tree(dtbuf,strbuf, flatname, flags);
+                       add_child(node, child);
+                       break;
+
+               case FDT_END_NODE:
+                       break;
+
+               case FDT_END:
+                       die("Premature FDT_END in device tree blob\n");
+                       break;
+
+               case FDT_NOP:
+                       if (!(flags & FTF_NOPS))
+                               fprintf(stderr, "Warning: NOP tag found in flat tree"
+                                       " version <16\n");
+
+                       /* Ignore */
+                       break;
+
+               default:
+                       die("Invalid opcode word %08x in device tree blob\n",
+                           val);
+               }
+       } while (val != FDT_END_NODE);
+
+       return node;
+}
+
+
+struct boot_info *dt_from_blob(const char *fname)
+{
+       FILE *f;
+       uint32_t magic, totalsize, version, size_dt, boot_cpuid_phys;
+       uint32_t off_dt, off_str, off_mem_rsvmap;
+       int rc;
+       char *blob;
+       struct fdt_header *fdt;
+       char *p;
+       struct inbuf dtbuf, strbuf;
+       struct inbuf memresvbuf;
+       int sizeleft;
+       struct reserve_info *reservelist;
+       struct node *tree;
+       uint32_t val;
+       int flags = 0;
+
+       f = srcfile_relative_open(fname, NULL);
+
+       rc = fread(&magic, sizeof(magic), 1, f);
+       if (ferror(f))
+               die("Error reading DT blob magic number: %s\n",
+                   strerror(errno));
+       if (rc < 1) {
+               if (feof(f))
+                       die("EOF reading DT blob magic number\n");
+               else
+                       die("Mysterious short read reading magic number\n");
+       }
+
+       magic = fdt32_to_cpu(magic);
+       if (magic != FDT_MAGIC)
+               die("Blob has incorrect magic number\n");
+
+       rc = fread(&totalsize, sizeof(totalsize), 1, f);
+       if (ferror(f))
+               die("Error reading DT blob size: %s\n", strerror(errno));
+       if (rc < 1) {
+               if (feof(f))
+                       die("EOF reading DT blob size\n");
+               else
+                       die("Mysterious short read reading blob size\n");
+       }
+
+       totalsize = fdt32_to_cpu(totalsize);
+       if (totalsize < FDT_V1_SIZE)
+               die("DT blob size (%d) is too small\n", totalsize);
+
+       blob = xmalloc(totalsize);
+
+       fdt = (struct fdt_header *)blob;
+       fdt->magic = cpu_to_fdt32(magic);
+       fdt->totalsize = cpu_to_fdt32(totalsize);
+
+       sizeleft = totalsize - sizeof(magic) - sizeof(totalsize);
+       p = blob + sizeof(magic)  + sizeof(totalsize);
+
+       while (sizeleft) {
+               if (feof(f))
+                       die("EOF before reading %d bytes of DT blob\n",
+                           totalsize);
+
+               rc = fread(p, 1, sizeleft, f);
+               if (ferror(f))
+                       die("Error reading DT blob: %s\n",
+                           strerror(errno));
+
+               sizeleft -= rc;
+               p += rc;
+       }
+
+       off_dt = fdt32_to_cpu(fdt->off_dt_struct);
+       off_str = fdt32_to_cpu(fdt->off_dt_strings);
+       off_mem_rsvmap = fdt32_to_cpu(fdt->off_mem_rsvmap);
+       version = fdt32_to_cpu(fdt->version);
+       boot_cpuid_phys = fdt32_to_cpu(fdt->boot_cpuid_phys);
+
+       if (off_mem_rsvmap >= totalsize)
+               die("Mem Reserve structure offset exceeds total size\n");
+
+       if (off_dt >= totalsize)
+               die("DT structure offset exceeds total size\n");
+
+       if (off_str > totalsize)
+               die("String table offset exceeds total size\n");
+
+       if (version >= 3) {
+               uint32_t size_str = fdt32_to_cpu(fdt->size_dt_strings);
+               if (off_str+size_str > totalsize)
+                       die("String table extends past total size\n");
+               inbuf_init(&strbuf, blob + off_str, blob + off_str + size_str);
+       } else {
+               inbuf_init(&strbuf, blob + off_str, blob + totalsize);
+       }
+
+       if (version >= 17) {
+               size_dt = fdt32_to_cpu(fdt->size_dt_struct);
+               if (off_dt+size_dt > totalsize)
+                       die("Structure block extends past total size\n");
+       }
+
+       if (version < 16) {
+               flags |= FTF_FULLPATH | FTF_NAMEPROPS | FTF_VARALIGN;
+       } else {
+               flags |= FTF_NOPS;
+       }
+
+       inbuf_init(&memresvbuf,
+                  blob + off_mem_rsvmap, blob + totalsize);
+       inbuf_init(&dtbuf, blob + off_dt, blob + totalsize);
+
+       reservelist = flat_read_mem_reserve(&memresvbuf);
+
+       val = flat_read_word(&dtbuf);
+
+       if (val != FDT_BEGIN_NODE)
+               die("Device tree blob doesn't begin with FDT_BEGIN_NODE (begins with 0x%08x)\n", val);
+
+       tree = unflatten_tree(&dtbuf, &strbuf, "", flags);
+
+       val = flat_read_word(&dtbuf);
+       if (val != FDT_END)
+               die("Device tree blob doesn't end with FDT_END\n");
+
+       free(blob);
+
+       fclose(f);
+
+       return build_boot_info(reservelist, tree, boot_cpuid_phys);
+}