hw/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  *
   9  * This work is licensed under the GNU GPL license version 2 or later.
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <sys/types.h>
  15 #include <sys/stat.h>
  16 #include <fcntl.h>
  17 #include <unistd.h>
  18 #include <stdlib.h>
  19
  20 #include "config.h"
  21 #include "ppc440.h"
  22
  23 #ifdef CONFIG_LIBFDT
  24 #include "libfdt.h"
  25 #endif
  26
  27 #define DT_PROC_INTERFACE_PATH "/proc/device-tree"
  28
  29 /* FUNCTIONS FOR READING FROM DEVICE TREE OF HOST IN /PROC */
  30
  31 /* This function reads device-tree property files that are of
  32  * a single cell size
  33  */
  34 uint32_t read_proc_dt_prop_cell(char *path_in_device_tree)
  35 {
  36         char *buf = NULL;
  37         int i;
  38         uint32_t num;
  39         FILE *stream;
  40
  41         i = asprintf(&buf, "%s/%s", DT_PROC_INTERFACE_PATH,
  42                 path_in_device_tree);
  43
  44         if (i < 0) {
  45                 printf("%s: Unable to malloc string buffer buf\n",
  46                         __func__);
  47                 exit(1);
  48         }
  49
  50         stream = fopen(buf, "rb");
  51
  52         if (stream == NULL) {
  53                 printf("%s: Unable to open '%s'\n", __func__, buf);
  54                 exit(1);
  55         }
  56
  57         fread(&num, sizeof(num), 1, stream);
  58         fclose(stream);
  59         free(buf);
  60
  61         return num;
  62 }
  63
  64 /* FUNCTIONS FOR LOADING & MANIPULATION OF DEVICE TREE IN GUEST */
  65
  66 #ifdef CONFIG_LIBFDT
  67 /* support functions */
  68 static int get_offset_of_node(void *fdt, char *node_path)
  69 {
  70         int node_offset;
  71         node_offset = fdt_path_offset(fdt, node_path);
  72         if (node_offset < 0) {
  73                 printf("Unable to find node in device tree '%s'\n",
  74                         node_path);
  75                 exit(1);
  76         }
  77         return node_offset;
  78 }
  79
  80 /* public functions */
  81 void *load_device_tree(char *filename_path, unsigned long load_addr)
  82 {
  83         int dt_file_size;
  84         int dt_file_load_size;
  85         int new_dt_size;
  86         int ret;
  87         void *dt_file = NULL;
  88         void *fdt;
  89
  90         dt_file_size = get_image_size(filename_path);
  91         if (dt_file_size < 0) {
  92                 printf("Unable to get size of device tree file '%s'\n",
  93                         filename_path);
  94                 goto fail;
  95         }
  96
  97         /* First allocate space in qemu for device tree */
  98         dt_file = qemu_malloc(dt_file_size);
  99         if (dt_file == NULL) {
 100                 printf("Unable to allocate memory in qemu for device tree\n");
 101                 goto fail;
 102         }
 103         memset(dt_file, 0, dt_file_size);
 104
 105         dt_file_load_size = load_image(filename_path, dt_file);
 106
 107
 108         /* XXX Second we place new copy of 2x size in guest memory
 109          *  This give us enough room for manipulation.
 110          */
 111         new_dt_size = dt_file_size * 2;
 112
 113         fdt = (void *)load_addr;
 114
 115         ret = fdt_open_into(dt_file, fdt, new_dt_size);
 116         if (ret) {
 117                 printf("Unable to copy device tree in memory\n");
 118                 goto fail;
 119         }
 120
 121         /* Check sanity of device tree */
 122         if (fdt_check_header(fdt)) {
 123                 printf ("Device tree file loaded into memory is invalid: %s\n",
 124                         filename_path);
 125                 goto fail;
 126         }
 127         /* free qemu memory with old device tree */
 128         qemu_free(dt_file);
 129         return fdt;
 130
 131 fail:
 132         if (dt_file)
 133                 qemu_free(dt_file);
 134         return NULL;
 135 }
 136
 137 void dump_device_tree_to_file(void *fdt, char *filename)
 138 {
 139         int fd;
 140         fd = open(filename, O_RDWR|O_CREAT, O_RDWR);
 141         if (fd < 0) {
 142                 printf("Failed to open file %s\n Cannot dum device-tree\n",
 143                         filename);
 144                 return;
 145         }
 146
 147         write(fd, fdt, fdt_totalsize(fdt));
 148         close(fd);
 149 }
 150
 151 void dt_cell(void *fdt, char *node_path, char *property,
 152                 uint32_t val)
 153 {
 154         int offset;
 155         int ret;
 156         offset = get_offset_of_node(fdt, node_path);
 157         ret = fdt_setprop_cell(fdt, offset, property, val);
 158         if (ret < 0) {
 159                 printf("Unable to set device tree property '%s'\n",
 160                         property);
 161                 exit(1);
 162         }
 163 }
 164
 165 /* This function is to manipulate a cell with multiple values */
 166 void dt_cell_multi(void *fdt, char *node_path, char *property,
 167                         uint32_t *val_array, int size)
 168 {
 169         int offset;
 170         int ret;
 171         offset = get_offset_of_node(fdt, node_path);
 172         ret = fdt_setprop(fdt, offset, property, val_array, size);
 173         if (ret < 0) {
 174                 printf("Unable to set device tree property '%s'\n",
 175                         property);
 176                 exit(1);
 177         }
 178 }
 179
 180 void dt_string(void *fdt, char *node_path, char *property,
 181                 char *string)
 182 {
 183         int offset;
 184         int ret;
 185         offset = get_offset_of_node(fdt, node_path);
 186         ret = fdt_setprop_string(fdt, offset, property, string);
 187         if (ret < 0) {
 188                 printf("Unable to set device tree property '%s'\n",
 189                         property);
 190                 exit(1);
 191         }
 192 }
 193 #endif