Subversion Repositories HelenOS

/*

 * 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 children. Node's peers are processed iteratively in order to prevent

 * stack from overflowing.

 *

 * @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;

    size_t len;

    int i;

    while (current_node) {

        /*

         * Initialize node.

         */

        current_node->parent = parent_node;

        current_node->peer = NULL;

        current_node->child = NULL;

        current_node->node_handle = current;

        current_node->properties = 0;

        current_node->property = NULL;

        current_node->device = 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;

        /* add space for trailing '\0' */

        current_node->da_name = ofw_tree_space_alloc(len + 1);

        if (!current_node->da_name)

            return;

        memcpy(current_node->da_name, &path[i], len);

        current_node->da_name[len] = '\0';

        /*

         * 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. */

        /*

         * Iteratively process the next peer node.

         * Note that recursion is a bad idea here.

         * Due to the topology of the OpenFirmware device tree,

         * the nesting of peer nodes could be to wide and the

         * risk of overflowing the stack is too real.

         */

        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) {

                current_node->peer = peer_node;

                current_node = peer_node;

                current = peer;

                /*

                 * Process the peer in next iteration.

                 */

                continue;

            }

        }

        /*

         * No more peers on this level.

         */

        break;

    }

}

/** 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;

    phandle ssm_node;

    ofw_tree_node_t *ssm;

    root = ofw_tree_node_alloc();

    if (root)

        ofw_tree_node_process(root, NULL, ofw_root);

    /*

     * The firmware client interface does not automatically include the

     * "ssm" node in the list of children of "/". A nasty yet working

     * solution is to explicitly stick "ssm" to the OFW tree.

     */

    ssm_node = ofw_find_device("/ssm@0,0");

    if (ssm_node != -1) {

        ssm = ofw_tree_node_alloc();

        if (ssm) {

            ofw_tree_node_process(

                ssm, root, ofw_find_device("/ssm@0,0"));

            ssm->peer = root->child;

            root->child = ssm;

        }

    }

    return root;

}