source: mainline/uspace/srv/devman/devtree.c@ c3d9aaf5

/*
 * Copyright (c) 2025 Jiri Svoboda
 * Copyright (c) 2010 Lenka Trochtova
 * 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.
 */

/** @addtogroup devman
 * @{
 */

#include <errno.h>
#include <io/log.h>

#include "dev.h"
#include "devtree.h"
#include "devman.h"
#include "driver.h"
#include "fun.h"

/* hash table operations */

static inline size_t handle_key_hash(const void *key)
{
        const devman_handle_t *handle = key;
        return *handle;
}

static size_t devman_devices_hash(const ht_link_t *item)
{
        dev_node_t *dev = hash_table_get_inst(item, dev_node_t, devman_dev);
        return handle_key_hash(&dev->handle);
}

static size_t devman_functions_hash(const ht_link_t *item)
{
        fun_node_t *fun = hash_table_get_inst(item, fun_node_t, devman_fun);
        return handle_key_hash(&fun->handle);
}

static bool devman_devices_key_equal(const void *key, const ht_link_t *item)
{
        const devman_handle_t *handle = key;
        dev_node_t *dev = hash_table_get_inst(item, dev_node_t, devman_dev);
        return dev->handle == *handle;
}

static bool devman_functions_key_equal(const void *key, const ht_link_t *item)
{
        const devman_handle_t *handle = key;
        fun_node_t *fun = hash_table_get_inst(item, fun_node_t, devman_fun);
        return fun->handle == *handle;
}

static inline size_t service_id_key_hash(const void *key)
{
        const service_id_t *service_id = key;
        return *service_id;
}

static size_t loc_functions_hash(const ht_link_t *item)
{
        fun_node_t *fun = hash_table_get_inst(item, fun_node_t, loc_fun);
        return service_id_key_hash(&fun->service_id);
}

static bool loc_functions_key_equal(const void *key, const ht_link_t *item)
{
        const service_id_t *service_id = key;
        fun_node_t *fun = hash_table_get_inst(item, fun_node_t, loc_fun);
        return fun->service_id == *service_id;
}

static const hash_table_ops_t devman_devices_ops = {
        .hash = devman_devices_hash,
        .key_hash = handle_key_hash,
        .key_equal = devman_devices_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

static const hash_table_ops_t devman_functions_ops = {
        .hash = devman_functions_hash,
        .key_hash = handle_key_hash,
        .key_equal = devman_functions_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

static const hash_table_ops_t loc_devices_ops = {
        .hash = loc_functions_hash,
        .key_hash = service_id_key_hash,
        .key_equal = loc_functions_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

/** Create root device and function node in the device tree.
 *
 * @param tree  The device tree.
 * @return      True on success, false otherwise.
 */
bool create_root_nodes(dev_tree_t *tree)
{
        fun_node_t *fun;
        dev_node_t *dev;

        log_msg(LOG_DEFAULT, LVL_DEBUG, "create_root_nodes()");

        fibril_rwlock_write_lock(&tree->rwlock);

        /*
         * Create root function. This is a pseudo function to which
         * the root device node is attached. It allows us to match
         * the root device driver in a standard manner, i.e. against
         * the parent function.
         */

        fun = create_fun_node();
        if (fun == NULL) {
                fibril_rwlock_write_unlock(&tree->rwlock);
                return false;
        }

        if (!insert_fun_node(tree, fun, str_dup(""), NULL)) {
                fun_del_ref(fun);       /* fun is destroyed */
                fibril_rwlock_write_unlock(&tree->rwlock);
                return false;
        }

        match_id_t *id = create_match_id();
        id->id = str_dup("root");
        id->score = 100;
        add_match_id(&fun->match_ids, id);
        tree->root_node = fun;

        /*
         * Create root device node.
         */
        dev = create_dev_node();
        if (dev == NULL) {
                fibril_rwlock_write_unlock(&tree->rwlock);
                return false;
        }

        insert_dev_node(tree, dev, fun);

        fibril_rwlock_write_unlock(&tree->rwlock);

        return dev != NULL;
}

/** Initialize the device tree.
 *
 * Create root device node of the tree and assign driver to it.
 *
 * @param tree          The device tree.
 * @param drivers_list  the list of available drivers.
 * @return              True on success, false otherwise.
 */
bool init_device_tree(dev_tree_t *tree, driver_list_t *drivers_list)
{
        log_msg(LOG_DEFAULT, LVL_DEBUG, "init_device_tree()");

        tree->current_handle = 0;

        hash_table_create(&tree->devman_devices, 0, 0, &devman_devices_ops);
        hash_table_create(&tree->devman_functions, 0, 0, &devman_functions_ops);
        hash_table_create(&tree->loc_functions, 0, 0, &loc_devices_ops);

        fibril_rwlock_initialize(&tree->rwlock);

        /* Create root function and root device and add them to the device tree. */
        if (!create_root_nodes(tree))
                return false;

        /* Find suitable driver and start it. */
        dev_node_t *rdev = tree->root_node->child;
        dev_add_ref(rdev);
        bool rc = assign_driver(rdev, drivers_list, tree);
        dev_del_ref(rdev);

        return rc;
}

/** Insert new device into device tree.
 *
 * @param tree          The device tree.
 * @param dev           The newly added device node.
 * @param pfun          The parent function node.
 *
 * @return              True on success, false otherwise (insufficient resources
 *                      etc.).
 */
bool insert_dev_node(dev_tree_t *tree, dev_node_t *dev, fun_node_t *pfun)
{
        assert(fibril_rwlock_is_write_locked(&tree->rwlock));

        log_msg(LOG_DEFAULT, LVL_DEBUG, "insert_dev_node(dev=%p, pfun=%p [\"%s\"])",
            dev, pfun, pfun->pathname);

        /* Add the node to the handle-to-node map. */
        dev->handle = ++tree->current_handle;
        hash_table_insert(&tree->devman_devices, &dev->devman_dev);

        /* Add the node to the list of its parent's children. */
        dev->pfun = pfun;
        pfun->child = dev;

        return true;
}

/** Remove device from device tree.
 *
 * @param tree          Device tree
 * @param dev           Device node
 */
void remove_dev_node(dev_tree_t *tree, dev_node_t *dev)
{
        assert(fibril_rwlock_is_write_locked(&tree->rwlock));

        log_msg(LOG_DEFAULT, LVL_DEBUG, "remove_dev_node(dev=%p)", dev);

        /* Remove node from the handle-to-node map. */
        hash_table_remove(&tree->devman_devices, &dev->handle);

        /* Unlink from parent function. */
        dev->pfun->child = NULL;
        dev->pfun = NULL;

        dev->state = DEVICE_REMOVED;
}

/** Insert new function into device tree.
 *
 * @param tree          The device tree.
 * @param fun           The newly added function node.
 * @param fun_name      The name of the newly added function.
 * @param dev           Owning device node.
 *
 * @return              True on success, false otherwise (insufficient resources
 *                      etc.).
 */
bool insert_fun_node(dev_tree_t *tree, fun_node_t *fun, char *fun_name,
    dev_node_t *dev)
{
        fun_node_t *pfun;

        assert(fun_name != NULL);
        assert(fibril_rwlock_is_write_locked(&tree->rwlock));

        /*
         * The root function is a special case, it does not belong to any
         * device so for the root function dev == NULL.
         */
        pfun = (dev != NULL) ? dev->pfun : NULL;

        fun->name = fun_name;
        if (!set_fun_path(tree, fun, pfun)) {
                return false;
        }

        /* Add the node to the handle-to-node map. */
        fun->handle = ++tree->current_handle;
        hash_table_insert(&tree->devman_functions, &fun->devman_fun);

        /* Add the node to the list of its parent's children. */
        fun->dev = dev;
        if (dev != NULL)
                list_append(&fun->dev_functions, &dev->functions);

        return true;
}

/** Remove function from device tree.
 *
 * @param tree          Device tree
 * @param node          Function node to remove
 */
void remove_fun_node(dev_tree_t *tree, fun_node_t *fun)
{
        assert(fibril_rwlock_is_write_locked(&tree->rwlock));

        /* Remove the node from the handle-to-node map. */
        hash_table_remove(&tree->devman_functions, &fun->handle);

        /* Remove the node from the list of its parent's children. */
        if (fun->dev != NULL)
                list_remove(&fun->dev_functions);

        fun->dev = NULL;
        fun->state = FUN_REMOVED;
}

/** Wait for device tree to stabilize.
 *
 * Blocks until the entire device tree had a chance to finish attaching
 * all devices.
 *
 * @param tree Device tree
 */
void dev_tree_wait_stable(dev_tree_t *tree)
{
        dev_wait_stable(tree->root_node->child);
}

/** @}
 */