device_tree.c

   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 <stdio.h>
  15 #include <sys/types.h>
  16 #include <sys/stat.h>
  17 #include <fcntl.h>
  18 #include <unistd.h>
  19 #include <stdlib.h>
  20
  21 #include "config.h"
  22 #include "qemu-common.h"
  23 #include "device_tree.h"
  24 #include "hw/loader.h"
  25
  26 #include <libfdt.h>
  27
  28 void *load_device_tree(const char *filename_path, int *sizep)
  29 {
  30     int dt_size;
  31     int dt_file_load_size;
  32     int ret;
  33     void *fdt = NULL;
  34
  35     *sizep = 0;
  36     dt_size = get_image_size(filename_path);
  37     if (dt_size < 0) {
  38         printf("Unable to get size of device tree file '%s'\n",
  39             filename_path);
  40         goto fail;
  41     }
  42
  43     /* Expand to 2x size to give enough room for manipulation.  */
  44     dt_size += 10000;
  45     dt_size *= 2;
  46     /* First allocate space in qemu for device tree */
  47     fdt = g_malloc0(dt_size);
  48
  49     dt_file_load_size = load_image(filename_path, fdt);
  50     if (dt_file_load_size < 0) {
  51         printf("Unable to open device tree file '%s'\n",
  52                filename_path);
  53         goto fail;
  54     }
  55
  56     ret = fdt_open_into(fdt, fdt, dt_size);
  57     if (ret) {
  58         printf("Unable to copy device tree in memory\n");
  59         goto fail;
  60     }
  61
  62     /* Check sanity of device tree */
  63     if (fdt_check_header(fdt)) {
  64         printf ("Device tree file loaded into memory is invalid: %s\n",
  65             filename_path);
  66         goto fail;
  67     }
  68     *sizep = dt_size;
  69     return fdt;
  70
  71 fail:
  72     g_free(fdt);
  73     return NULL;
  74 }
  75
  76 static int findnode_nofail(void *fdt, const char *node_path)
  77 {
  78     int offset;
  79
  80     offset = fdt_path_offset(fdt, node_path);
  81     if (offset < 0) {
  82         fprintf(stderr, "%s Couldn't find node %s: %s\n", __func__, node_path,
  83                 fdt_strerror(offset));
  84         exit(1);
  85     }
  86
  87     return offset;
  88 }
  89
  90 int qemu_devtree_setprop(void *fdt, const char *node_path,
  91                          const char *property, void *val_array, int size)
  92 {
  93     int r;
  94
  95     r = fdt_setprop(fdt, findnode_nofail(fdt, node_path), property, val_array, size);
  96     if (r < 0) {
  97         fprintf(stderr, "%s: Couldn't set %s/%s: %s\n", __func__, node_path,
  98                 property, fdt_strerror(r));
  99         exit(1);
 100     }
 101
 102     return r;
 103 }
 104
 105 int qemu_devtree_setprop_cell(void *fdt, const char *node_path,
 106                               const char *property, uint32_t val)
 107 {
 108     int r;
 109
 110     r = fdt_setprop_cell(fdt, findnode_nofail(fdt, node_path), property, val);
 111     if (r < 0) {
 112         fprintf(stderr, "%s: Couldn't set %s/%s = %#08x: %s\n", __func__,
 113                 node_path, property, val, fdt_strerror(r));
 114         exit(1);
 115     }
 116
 117     return r;
 118 }
 119
 120 int qemu_devtree_setprop_string(void *fdt, const char *node_path,
 121                                 const char *property, const char *string)
 122 {
 123     int r;
 124
 125     r = fdt_setprop_string(fdt, findnode_nofail(fdt, node_path), property, string);
 126     if (r < 0) {
 127         fprintf(stderr, "%s: Couldn't set %s/%s = %s: %s\n", __func__,
 128                 node_path, property, string, fdt_strerror(r));
 129         exit(1);
 130     }
 131
 132     return r;
 133 }
 134
 135 int qemu_devtree_nop_node(void *fdt, const char *node_path)
 136 {
 137     int r;
 138
 139     r = fdt_nop_node(fdt, findnode_nofail(fdt, node_path));
 140     if (r < 0) {
 141         fprintf(stderr, "%s: Couldn't nop node %s: %s\n", __func__, node_path,
 142                 fdt_strerror(r));
 143         exit(1);
 144     }
 145
 146     return r;
 147 }
 148
 149 int qemu_devtree_add_subnode(void *fdt, const char *name)
 150 {
 151     char *dupname = g_strdup(name);
 152     char *basename = strrchr(dupname, '/');
 153     int retval;
 154
 155     if (!basename) {
 156         return -1;
 157     }
 158
 159     basename[0] = '\0';
 160     basename++;
 161
 162     retval = fdt_add_subnode(fdt, findnode_nofail(fdt, dupname), basename);
 163     if (retval < 0) {
 164         fprintf(stderr, "FDT: Failed to create subnode %s: %s\n", name,
 165                 fdt_strerror(retval));
 166         exit(1);
 167     }
 168
 169     g_free(dupname);
 170     return retval;
 171 }