boot/genarch/ofw_tree.c

   1 /*
   2  * Copyright (c) 2006 Jakub Jermar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <ofw_tree.h>
  30 #include <ofw.h>
  31 #include <types.h>
  32 #include <string.h>
  33 #include <balloc.h>
  34 #include <asm.h>
  35
  36 #define MAX_PATH_LEN    256
  37
  38 static ofw_tree_node_t *ofw_tree_node_alloc(void)
  39 {
  40         return balloc(sizeof(ofw_tree_node_t), sizeof(ofw_tree_node_t));
  41 }
  42
  43 static ofw_tree_property_t *ofw_tree_properties_alloc(unsigned count)
  44 {
  45         return balloc(count * sizeof(ofw_tree_property_t), sizeof(ofw_tree_property_t));
  46 }
  47
  48 static void * ofw_tree_space_alloc(size_t size)
  49 {
  50         char *addr;
  51
  52         /*
  53          * What we do here is a nasty hack :-)
  54          * Problem: string property values that are allocated via this
  55          * function typically do not contain the trailing '\0'. This
  56          * is very uncomfortable for kernel, which is supposed to deal
  57          * with the properties.
  58          * Solution: when allocating space via this function, we always
  59          * allocate space for the extra '\0' character that we store
  60          * behind the requested memory.
  61          */
  62         addr = balloc(size + 1, size);
  63         if (addr)
  64                 addr[size] = '\0';
  65         return addr;
  66 }
  67
  68 /** Transfer information from one OpenFirmware node into its memory representation.
  69  *
  70  * Transfer entire information from the OpenFirmware device tree 'current' node to
  71  * its memory representation in 'current_node'. This function recursively processes
  72  * all node's children. Node's peers are processed iteratively in order to prevent
  73  * stack from overflowing.
  74  *
  75  * @param current_node  Pointer to uninitialized ofw_tree_node structure that will
  76  *                      become the memory represenation of 'current'.
  77  * @param parent_node   Parent ofw_tree_node structure or NULL in case of root node.
  78  * @param current       OpenFirmware phandle to the current device tree node.
  79  */
  80 static void ofw_tree_node_process(ofw_tree_node_t *current_node,
  81         ofw_tree_node_t *parent_node, phandle current)
  82 {
  83         static char path[MAX_PATH_LEN+1];
  84         static char name[OFW_TREE_PROPERTY_MAX_NAMELEN];
  85         phandle peer;
  86         phandle child;
  87         size_t len;
  88         int i;
  89
  90         while (current_node) {
  91                 /*
  92                  * Initialize node.
  93                  */
  94                 current_node->parent = parent_node;
  95                 current_node->peer = NULL;
  96                 current_node->child = NULL;
  97                 current_node->node_handle = current;
  98                 current_node->properties = 0;
  99                 current_node->property = NULL;
 100                 current_node->device = NULL;
 101
 102                 /*
 103                  * Get the disambigued name.
 104                  */
 105                 len = ofw_package_to_path(current, path, MAX_PATH_LEN);
 106                 if (len == -1)
 107                         return;
 108
 109                 path[len] = '\0';
 110                 for (i = len - 1; i >= 0 && path[i] != '/'; i--)
 111                         ;
 112                 i++;    /* do not include '/' */
 113
 114                 len -= i;
 115
 116                 /* add space for trailing '\0' */
 117                 current_node->da_name = ofw_tree_space_alloc(len + 1);
 118                 if (!current_node->da_name)
 119                         return;
 120
 121                 memcpy(current_node->da_name, &path[i], len);
 122                 current_node->da_name[len] = '\0';
 123
 124
 125                 /*
 126                  * Recursively process the potential child node.
 127                  */
 128                 child = ofw_get_child_node(current);
 129                 if (child != 0 && child != -1) {
 130                         ofw_tree_node_t *child_node;
 131
 132                         child_node = ofw_tree_node_alloc();
 133                         if (child_node) {
 134                                 ofw_tree_node_process(child_node, current_node, child);
 135                                 current_node->child = child_node;
 136                         }
 137                 }
 138
 139                 /*
 140                  * Count properties.
 141                  */
 142                 name[0] = '\0';
 143                 while (ofw_next_property(current, name, name) == 1)
 144                         current_node->properties++;
 145
 146                 if (!current_node->properties)
 147                         return;
 148
 149                 /*
 150                  * Copy properties.
 151                  */
 152                 current_node->property = ofw_tree_properties_alloc(current_node->properties);
 153                 if (!current_node->property)
 154                         return;
 155
 156                 name[0] = '\0';
 157                 for (i = 0; ofw_next_property(current, name, name) == 1; i++) {
 158                         size_t size;
 159
 160                         if (i == current_node->properties)
 161                                 break;
 162
 163                         memcpy(current_node->property[i].name, name,
 164                                 OFW_TREE_PROPERTY_MAX_NAMELEN);
 165                         current_node->property[i].name[OFW_TREE_PROPERTY_MAX_NAMELEN] = '\0';
 166
 167                         size = ofw_get_proplen(current, name);
 168                         current_node->property[i].size = size;
 169                         if (size) {
 170                                 void *buf;
 171
 172                                 buf = ofw_tree_space_alloc(size);
 173                                 if (current_node->property[i].value = buf) {
 174                                         /*
 175                                          * Copy property value to memory node.
 176                                          */
 177                                         (void) ofw_get_property(current, name, buf, size);
 178                                 }
 179                         } else {
 180                                 current_node->property[i].value = NULL;
 181                         }
 182                 }
 183
 184                 current_node->properties = i;   /* Just in case we ran out of memory. */
 185
 186                 /*
 187                  * Iteratively process the next peer node.
 188                  * Note that recursion is a bad idea here.
 189                  * Due to the topology of the OpenFirmware device tree,
 190                  * the nesting of peer nodes could be to wide and the
 191                  * risk of overflowing the stack is too real.
 192                  */
 193                 peer = ofw_get_peer_node(current);
 194                 if (peer != 0 && peer != -1) {
 195                         ofw_tree_node_t *peer_node;
 196
 197                         peer_node = ofw_tree_node_alloc();
 198                         if (peer_node) {
 199                                 current_node->peer = peer_node;
 200                                 current_node = peer_node;
 201                                 current = peer;
 202                                 /*
 203                                  * Process the peer in next iteration.
 204                                  */
 205                                 continue;
 206                         }
 207                 }
 208                 /*
 209                  * No more peers on this level.
 210                  */
 211                 break;
 212         }
 213 }
 214
 215 /** Construct memory representation of OpenFirmware device tree.
 216  *
 217  * @return NULL on failure or pointer to the root node.
 218  */
 219 ofw_tree_node_t *ofw_tree_build(void)
 220 {
 221         ofw_tree_node_t *root;
 222
 223         root = ofw_tree_node_alloc();
 224         if (root)
 225                 ofw_tree_node_process(root, NULL, ofw_root);
 226
 227         return root;
 228 }