Implement device tree support needed for Bamboo emulation

To implement the -kernel, -initrd, and -append options, 4xx board emulation
must load the guest kernel as if firmware had loaded it. Where u-boot would be
the firmware, we must load the flat device tree into memory and set key fields
such as /chosen/bootargs.

This patch introduces a dependency on libfdt for flat device tree support.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6064 c046a42c-6fe2-441c-8c8c-71466251a162

device_tree.c

@@ -0,0 +1,114 @@
+/*
+ * Functions to help device tree manipulation using libfdt.
+ * It also provides functions to read entries from device tree proc
+ * interface.
+ *
+ * Copyright 2008 IBM Corporation.
+ * Authors: Jerone Young <jyoung5@us.ibm.com>
+ *          Hollis Blanchard <hollisb@us.ibm.com>
+ *
+ * This work is licensed under the GNU GPL license version 2 or later.
+ *
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "config.h"
+#include "qemu-common.h"
+#include "sysemu.h"
+#include "device_tree.h"
+
+#include <libfdt.h>
+
+void *load_device_tree(const char *filename_path, void *load_addr)
+{
+    int dt_file_size;
+    int dt_file_load_size;
+    int new_dt_size;
+    int ret;
+    void *dt_file = NULL;
+    void *fdt;
+
+    dt_file_size = get_image_size(filename_path);
+    if (dt_file_size < 0) {
+        printf("Unable to get size of device tree file '%s'\n",
+            filename_path);
+        goto fail;
+    }
+
+    /* First allocate space in qemu for device tree */
+    dt_file = qemu_mallocz(dt_file_size);
+    if (dt_file == NULL) {
+        printf("Unable to allocate memory in qemu for device tree\n");
+        goto fail;
+    }
+
+    dt_file_load_size = load_image(filename_path, dt_file);
+
+    /* Second we place new copy of 2x size in guest memory
+     * This give us enough room for manipulation.
+     */
+    new_dt_size = dt_file_size * 2;
+
+    fdt = load_addr;
+    ret = fdt_open_into(dt_file, fdt, new_dt_size);
+    if (ret) {
+        printf("Unable to copy device tree in memory\n");
+        goto fail;
+    }
+
+    /* Check sanity of device tree */
+    if (fdt_check_header(fdt)) {
+        printf ("Device tree file loaded into memory is invalid: %s\n",
+            filename_path);
+        goto fail;
+    }
+    /* free qemu memory with old device tree */
+    qemu_free(dt_file);
+    return fdt;
+
+fail:
+    qemu_free(dt_file);
+    return NULL;
+}
+
+int qemu_devtree_setprop(void *fdt, const char *node_path,
+                         const char *property, uint32_t *val_array, int size)
+{
+    int offset;
+
+    offset = fdt_path_offset(fdt, node_path);
+    if (offset < 0)
+        return offset;
+
+    return fdt_setprop(fdt, offset, property, val_array, size);
+}
+
+int qemu_devtree_setprop_cell(void *fdt, const char *node_path,
+                              const char *property, uint32_t val)
+{
+    int offset;
+
+    offset = fdt_path_offset(fdt, node_path);
+    if (offset < 0)
+        return offset;
+
+    return fdt_setprop_cell(fdt, offset, property, val);
+}
+
+int qemu_devtree_setprop_string(void *fdt, const char *node_path,
+                                const char *property, const char *string)
+{
+    int offset;
+
+    offset = fdt_path_offset(fdt, node_path);
+    if (offset < 0)
+        return offset;
+
+    return fdt_setprop_string(fdt, offset, property, string);
+}