source: mainline/boot/genarch/ofw_tree.c@ 28ecadb

/*
 * Copyright (C) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <ofw_tree.h>
#include <ofw.h>
#include <types.h>
#include <string.h>
#include <balloc.h>
#include <asm.h>

#define MAX_PATH_LEN    256

static ofw_tree_node_t *ofw_tree_node_alloc(void)
{
        return balloc(sizeof(ofw_tree_node_t), sizeof(ofw_tree_node_t));
}

static ofw_tree_property_t *ofw_tree_properties_alloc(unsigned count)
{
        return balloc(count * sizeof(ofw_tree_property_t), sizeof(ofw_tree_property_t));
}

static void * ofw_tree_space_alloc(size_t size)
{
        char *addr;

        /*
         * What we do here is a nasty hack :-)
         * Problem: string property values that are allocated via this
         * function typically do not contain the trailing '\0'. This
         * is very uncomfortable for kernel, which is supposed to deal
         * with the properties.
         * Solution: when allocating space via this function, we always
         * allocate space for the extra '\0' character that we store
         * behind the requested memory.
         */
        addr = balloc(size + 1, size);
        if (addr)
                addr[size] = '\0';
        return addr;
}

/** Transfer information from one OpenFirmware node into its memory representation.
 *
 * Transfer entire information from the OpenFirmware device tree 'current' node to
 * its memory representation in 'current_node'. This function recursively processes
 * all node's peers and children.
 *
 * @param current_node  Pointer to uninitialized ofw_tree_node structure that will
 *                      become the memory represenation of 'current'.
 * @param parent_node   Parent ofw_tree_node structure or NULL in case of root node.
 * @param current       OpenFirmware phandle to the current device tree node.
 */
static void ofw_tree_node_process(ofw_tree_node_t *current_node,
        ofw_tree_node_t *parent_node, phandle current)
{
        static char path[MAX_PATH_LEN+1];
        static char name[OFW_TREE_PROPERTY_MAX_NAMELEN];
        phandle peer;
        phandle child;
        unsigned properties = 0;
        size_t len;
        int i;

        /*
         * Initialize node.
         */
        current_node->parent = parent_node;
        current_node->peer = NULL;
        current_node->child = NULL;
        current_node->properties = 0;
        current_node->property = NULL;
        
        /*
         * Get the disambigued name.
         */
        len = ofw_package_to_path(current, path, MAX_PATH_LEN);
        if (len == -1)
                return;
        
        path[len] = '\0';
        for (i = len - 1; i >= 0 && path[i] != '/'; i--)
                ;
        i++;                                                            /* do not include '/' */
        
        len -= i;
        current_node->da_name = ofw_tree_space_alloc(len + 1);          /* add space for trailing '\0' */
        if (!current_node->da_name)
                return;
        
        memcpy(current_node->da_name, &path[i], len);
        current_node->da_name[len] = '\0';
        
        /*
         * Recursively process the potential peer node.
         */
        peer = ofw_get_peer_node(current);
        if (peer != 0 && peer != -1) {
                ofw_tree_node_t *peer_node;
                
                peer_node = ofw_tree_node_alloc();
                if (peer_node) {
                        ofw_tree_node_process(peer_node, parent_node, peer);
                        current_node->peer = peer_node;
                }
        }
        
        /*
         * Recursively process the potential child node.
         */
        child = ofw_get_child_node(current);
        if (child != 0 && child != -1) {
                ofw_tree_node_t *child_node;
                
                child_node = ofw_tree_node_alloc();
                if (child_node) {
                        ofw_tree_node_process(child_node, current_node, child);
                        current_node->child = child_node;
                }
        }
        
        /*
         * Count properties.
         */
        name[0] = '\0';
        while (ofw_next_property(current, name, name) == 1)
                current_node->properties++;
        
        if (!current_node->properties)
                return;
        
        /*
         * Copy properties.
         */
        current_node->property = ofw_tree_properties_alloc(current_node->properties);
        if (!current_node->property)
                return;
                
        name[0] = '\0';
        for (i = 0; ofw_next_property(current, name, name) == 1; i++) {
                size_t size;
                
                if (i == current_node->properties)
                        break;
                
                memcpy(current_node->property[i].name, name, OFW_TREE_PROPERTY_MAX_NAMELEN);
                current_node->property[i].name[OFW_TREE_PROPERTY_MAX_NAMELEN] = '\0';

                size = ofw_get_proplen(current, name);
                current_node->property[i].size = size;
                if (size) {
                        void *buf;
                        
                        buf = ofw_tree_space_alloc(size);
                        if (current_node->property[i].value = buf) {
                                /*
                                 * Copy property value to memory node.
                                 */
                                (void) ofw_get_property(current, name, buf, size);
                        }
                } else {
                        current_node->property[i].value = NULL;
                }
        }
                
        current_node->properties = i;   /* Just in case we ran out of memory. */
}

/** Construct memory representation of OpenFirmware device tree.
 *
 * @return NULL on failure or pointer to the root node.
 */
ofw_tree_node_t *ofw_tree_build(void)
{
        ofw_tree_node_t *root;
        
        root = ofw_tree_node_alloc();
        if (root)
                ofw_tree_node_process(root, NULL, ofw_root);
        
        return root;
}