source: mainline/uspace/srv/devman/devman.c@ a32defa

/*
 * 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 <fcntl.h>
#include <sys/stat.h>
#include <ipc/driver.h>
#include <ipc/devman.h>
#include <devmap.h>

#include "devman.h"

// hash table operations

static hash_index_t devices_hash(unsigned long key[])
{
        return key[0] % DEVICE_BUCKETS;
}

static int devman_devices_compare(unsigned long key[], hash_count_t keys, link_t *item)
{
        node_t *dev = hash_table_get_instance(item, node_t, devman_link);
        return (dev->handle == (device_handle_t) key[0]);
}

static int devmap_devices_compare(unsigned long key[], hash_count_t keys, link_t *item)
{
        node_t *dev = hash_table_get_instance(item, node_t, devmap_link);
        return (dev->devmap_handle == (dev_handle_t) key[0]);
}

static void devices_remove_callback(link_t *item)
{
}

static hash_table_operations_t devman_devices_ops = {
        .hash = devices_hash,
        .compare = devman_devices_compare,
        .remove_callback = devices_remove_callback
};

static hash_table_operations_t devmap_devices_ops = {
        .hash = devices_hash,
        .compare = devmap_devices_compare,
        .remove_callback = devices_remove_callback
};

/** Allocate and initialize a new driver structure.
 * 
 * @return driver structure.
 */
driver_t * create_driver() 
{       
        driver_t *res = malloc(sizeof(driver_t));
        if(res != NULL) {
                init_driver(res);
        }
        return res;
}

/** Add a driver to the list of drivers.
 * 
 * @param drivers_list the list of drivers.
 * @param drv the driver's structure.
 */
void add_driver(driver_list_t *drivers_list, driver_t *drv)
{
        fibril_mutex_lock(&drivers_list->drivers_mutex);
        list_prepend(&drv->drivers, &drivers_list->drivers);
        fibril_mutex_unlock(&drivers_list->drivers_mutex);
        
        printf(NAME": the '%s' driver was added to the list of available drivers.\n", drv->name);
}

/** Read match id at the specified position of a string and set 
 * the position in the string to the first character following the id.
 * 
 * @param buf the position in the input string.
 * 
 * @return the match id. 
 */
char * read_match_id(char **buf) 
{
        char *res = NULL;
        size_t len = get_nonspace_len(*buf);
        if (len > 0) {
                res = malloc(len + 1);
                if (res != NULL) {
                        str_ncpy(res, len + 1, *buf, len);      
                        *buf += len;
                }
        }
        return res;
}

/**
 * Read match ids and associated match scores from a string.
 * 
 * Each match score in the string is followed by its match id. 
 * The match ids and match scores are separated by whitespaces. 
 * Neither match ids nor match scores can contain whitespaces. 
 * 
 * @param buf the string from which the match ids are read.
 * @param ids the list of match ids into which the match ids and scores are added.
 * 
 * @return true if at least one match id and associated match score was successfully read, false otherwise.
 */
bool parse_match_ids(char *buf, match_id_list_t *ids)
{
        int score = 0;
        char *id = NULL;
        int ids_read = 0;
        
        while (true) {
                // skip spaces
                if (!skip_spaces(&buf)) {
                        break;
                }
                // read score
                score = strtoul(buf, &buf, 10);
                
                // skip spaces
                if (!skip_spaces(&buf)) {
                        break;
                }
                
                // read id
                if (NULL == (id = read_match_id(&buf))) {
                        break;                  
                }
                
                // create new match_id structure
                match_id_t *mid = create_match_id();
                mid->id = id;
                mid->score = score;
                
                /// add it to the list
                add_match_id(ids, mid);
                
                ids_read++;             
        }       
        
        return ids_read > 0;
}

/**
 * Read match ids and associated match scores from a file.
 * 
 * Each match score in the file is followed by its match id. 
 * The match ids and match scores are separated by whitespaces. 
 * Neither match ids nor match scores can contain whitespaces. 
 * 
 * @param buf the path to the file from which the match ids are read.
 * @param ids the list of match ids into which the match ids and scores are added.
 * 
 * @return true if at least one match id and associated match score was successfully read, false otherwise.
 */
bool read_match_ids(const char *conf_path, match_id_list_t *ids) 
{       
        printf(NAME ": read_match_ids conf_path = %s.\n", conf_path);
        
        bool suc = false;       
        char *buf = NULL;
        bool opened = false;
        int fd;         
        size_t len = 0;
        
        fd = open(conf_path, O_RDONLY);
        if (fd < 0) {
                printf(NAME ": unable to open %s\n", conf_path);
                goto cleanup;
        } 
        opened = true;  
        
        len = lseek(fd, 0, SEEK_END);
        lseek(fd, 0, SEEK_SET); 
        if (len == 0) {
                printf(NAME ": configuration file '%s' is empty.\n", conf_path);
                goto cleanup;           
        }
        
        buf = malloc(len + 1);
        if (buf == NULL) {
                printf(NAME ": memory allocation failed when parsing file '%s'.\n", conf_path);
                goto cleanup;
        }       
        
        if (0 >= read(fd, buf, len)) {
                printf(NAME ": unable to read file '%s'.\n", conf_path);
                goto cleanup;
        }
        buf[len] = 0;
        
        suc = parse_match_ids(buf, ids);
        
cleanup:
        
        free(buf);
        
        if(opened) {
                close(fd);      
        }
        
        return suc;
}

/**
 * Get information about a driver.
 * 
 * Each driver has its own directory in the base directory. 
 * The name of the driver's directory is the same as the name of the driver.
 * The driver's directory contains driver's binary (named as the driver without extension)
 * and the configuration file with match ids for device-to-driver matching 
 * (named as the driver with a special extension).
 * 
 * This function searches for the driver's directory and containing configuration files.
 * If all the files needed are found, they are parsed and 
 * the information about the driver is stored to the driver's structure.
 * 
 * @param base_path the base directory, in which we look for driver's subdirectory.
 * @param name the name of the driver.
 * @param drv the driver structure to fill information in.
 * 
 * @return true on success, false otherwise.
 */
bool get_driver_info(const char *base_path, const char *name, driver_t *drv)
{
        printf(NAME ": get_driver_info base_path = %s, name = %s.\n", base_path, name);
        
        assert(base_path != NULL && name != NULL && drv != NULL);
        
        bool suc = false;
        char *match_path = NULL;        
        size_t name_size = 0;
        
        // read the list of match ids from the driver's configuration file
        if (NULL == (match_path = get_abs_path(base_path, name, MATCH_EXT))) {
                goto cleanup;
        }       
        
        if (!read_match_ids(match_path, &drv->match_ids)) {
                goto cleanup;
        }       
        
        // allocate and fill driver's name
        name_size = str_size(name)+1;
        drv->name = malloc(name_size);
        if (!drv->name) {
                goto cleanup;
        }       
        str_cpy(drv->name, name_size, name);
        
        // initialize path with driver's binary
        if (NULL == (drv->binary_path = get_abs_path(base_path, name, ""))) {
                goto cleanup;
        }
        
        // check whether the driver's binary exists
        struct stat s;
        if (stat(drv->binary_path, &s) == ENOENT) {
                printf(NAME ": driver not found at path %s.", drv->binary_path);
                goto cleanup;
        }
        
        suc = true;
        
cleanup:
        
        if (!suc) {
                free(drv->binary_path);
                free(drv->name);
                // set the driver structure to the default state
                init_driver(drv); 
        }
        
        free(match_path);
        
        return suc;
}

/** Lookup drivers in the directory.
 * 
 * @param drivers_list the list of available drivers.
 * @param dir_path the path to the directory where we search for drivers. 
 * 
 * @return number of drivers which were found.
 */ 
int lookup_available_drivers(driver_list_t *drivers_list, const char *dir_path)
{
        printf(NAME ": lookup_available_drivers, dir = %s \n", dir_path);
        
        int drv_cnt = 0;
        DIR *dir = NULL;
        struct dirent *diren;

        dir = opendir(dir_path);
        
        if (dir != NULL) {
                driver_t *drv = create_driver();
                while ((diren = readdir(dir))) {                        
                        if (get_driver_info(dir_path, diren->d_name, drv)) {
                                add_driver(drivers_list, drv);
                                drv_cnt++;
                                drv = create_driver();
                        }       
                }
                delete_driver(drv);
                closedir(dir);
        }
        
        return drv_cnt;
}

/** Create root device node in the device tree.
 * 
 * @param tree the device tree.
 * @return true on success, false otherwise.
 */
bool create_root_node(dev_tree_t *tree)
{
        printf(NAME ": create_root_node\n");
        node_t *node = create_dev_node();
        if (node) {             
                insert_dev_node(tree, node, clone_string(""), NULL);
                match_id_t *id = create_match_id();
                id->id = clone_string("root");
                id->score = 100;
                add_match_id(&node->match_ids, id);
                tree->root_node = node;
        }
        return node != NULL;    
}

/** Lookup the best matching driver for the specified device in the list of drivers.
 * 
 * A match between a device and a driver is found 
 * if one of the driver's match ids match one of the device's match ids.
 * The score of the match is the product of the driver's and device's score associated with the matching id.
 * The best matching driver for a device is the driver
 * with the highest score of the match between the device and the driver.
 * 
 * @param drivers_list the list of drivers, where we look for the driver suitable for handling the device.
 * @param node the device node structure of the device.
 *
 * @return the best matching driver or NULL if no matching driver is found.
 */
driver_t * find_best_match_driver(driver_list_t *drivers_list, node_t *node)
{
        //printf(NAME ": find_best_match_driver for device '%s' \n", node->pathname);
        driver_t *best_drv = NULL, *drv = NULL;
        int best_score = 0, score = 0;
        
        fibril_mutex_lock(&drivers_list->drivers_mutex);
        
        link_t *link = drivers_list->drivers.next;              
        while (link != &drivers_list->drivers) {
                drv = list_get_instance(link, driver_t, drivers);
                score = get_match_score(drv, node);
                if (score > best_score) {
                        best_score = score;
                        best_drv = drv;
                }       
                link = link->next;
        }
        
        fibril_mutex_unlock(&drivers_list->drivers_mutex);
        
        return best_drv;        
}

/**
 * Assign a driver to a device.
 * 
 * @param node the device's node in the device tree.
 * @param drv the driver.
 */
void attach_driver(node_t *node, driver_t *drv) 
{
        printf(NAME ": attach_driver %s to device %s\n", drv->name, node->pathname);
        
        fibril_mutex_lock(&drv->driver_mutex);
        
        node->drv = drv;
        list_append(&node->driver_devices, &drv->devices);
        
        fibril_mutex_unlock(&drv->driver_mutex);
}

/** Start a driver.
 * 
 * The driver's mutex is assumed to be locked.
 * 
 * @param drv the driver's structure.
 * @return true if the driver's task is successfully spawned, false otherwise.
 */
bool start_driver(driver_t *drv)
{
        printf(NAME ": start_driver '%s'\n", drv->name);
        
        const char *argv[2];
        
        argv[0] = drv->name;
        argv[1] = NULL;
        
        int err;
        if (!task_spawn(drv->binary_path, argv, &err)) {
                printf(NAME ": error spawning %s, errno = %d\n", drv->name, err);
                return false;
        }
        
        drv->state = DRIVER_STARTING;
        return true;
}

/** Find device driver in the list of device drivers.
 * 
 * @param drv_list the list of device drivers.
 * @param drv_name the name of the device driver which is searched.
 * @return the device driver of the specified name, if it is in the list, NULL otherwise.  
 */
driver_t * find_driver(driver_list_t *drv_list, const char *drv_name) 
{       
        driver_t *res = NULL;
        
        fibril_mutex_lock(&drv_list->drivers_mutex);    
        
        driver_t *drv = NULL;
        link_t *link = drv_list->drivers.next;  
        while (link !=  &drv_list->drivers) {
                drv = list_get_instance(link, driver_t, drivers);
                if (0 == str_cmp(drv->name, drv_name)) {
                        res = drv;
                        break;
                }               
                link = link->next;
        }       
        
        fibril_mutex_unlock(&drv_list->drivers_mutex);
        
        return res;
}

/** Remember the driver's phone.
 * @param driver the driver.
 * @param phone the phone to the driver.
 */
void set_driver_phone(driver_t *driver, ipcarg_t phone)
{               
        fibril_mutex_lock(&driver->driver_mutex);       
        assert(DRIVER_STARTING == driver->state);
        driver->phone = phone;  
        fibril_mutex_unlock(&driver->driver_mutex);     
}

/**
 * Notify driver about the devices to which it was assigned.
 * 
 * The driver's mutex must be locked.
 * 
 * @param driver the driver to which the devices are passed.
 */
static void pass_devices_to_driver(driver_t *driver, dev_tree_t *tree)
{       
        printf(NAME ": pass_devices_to_driver\n");
        node_t *dev;
        link_t *link;
        
        int phone = ipc_connect_me_to(driver->phone, DRIVER_DEVMAN, 0, 0);
        
        if (0 < phone) {
                
                link = driver->devices.next;
                while (link != &driver->devices) {
                        dev = list_get_instance(link, node_t, driver_devices);
                        add_device(phone, driver, dev, tree);
                        link = link->next;
                }
                
                ipc_hangup(phone);
        }
}

/** Finish the initialization of a driver after it has succesfully started 
 * and after it has registered itself by the device manager.
 * 
 * Pass devices formerly matched to the driver to the driver and remember the driver is running and fully functional now.
 * 
 * @param driver the driver which registered itself as running by the device manager.
 */
void initialize_running_driver(driver_t *driver, dev_tree_t *tree) 
{       
        printf(NAME ": initialize_running_driver\n");
        fibril_mutex_lock(&driver->driver_mutex);
        
        // pass devices which have been already assigned to the driver to the driver
        pass_devices_to_driver(driver, tree);   
        
        // change driver's state to running
        driver->state = DRIVER_RUNNING; 
        
        fibril_mutex_unlock(&driver->driver_mutex);
}


static void devmap_register_tree_device(node_t *node, dev_tree_t *tree)
{
        // create devmap path and name for the device
        char *devmap_pathname = NULL;
        char *devmap_name = NULL;
        
        asprintf(&devmap_name, "%s", node->pathname);
        if (NULL == devmap_name) {
                return;
        }
        
        replace_char(devmap_name, '/', DEVMAP_SEPARATOR);
        
        asprintf(&devmap_pathname, "%s/%s", DEVMAP_DEVICE_NAMESPACE, devmap_name);
        if (NULL == devmap_pathname) {
                free(devmap_name);
                return;
        }       
        
        devmap_device_register(devmap_pathname, &node->devmap_handle);
        
        tree_add_devmap_device(tree, node);
        
        free(devmap_name);
        free(devmap_pathname);  
}


/** Pass a device to running driver.
 * 
 * @param drv the driver's structure.
 * @param node the device's node in the device tree.
 */
void add_device(int phone, driver_t *drv, node_t *node, dev_tree_t *tree)
{
        printf(NAME ": add_device\n");
        
        ipcarg_t rc;
        ipc_call_t answer;
        
        // send the device to the driver
        aid_t req = async_send_1(phone, DRIVER_ADD_DEVICE, node->handle, &answer);
        
        // send the device's name to the driver
        rc = async_data_write_start(phone, node->name, str_size(node->name) + 1);
    if (rc != EOK) {
                // TODO handle error
    }
        
        // wait for answer from the driver
        async_wait_for(req, &rc);
        switch(rc) {
        case EOK:
                node->state = DEVICE_USABLE;
                devmap_register_tree_device(node, tree);
                break;
        case ENOENT:
                node->state = DEVICE_NOT_PRESENT;
                break;
        default:
                node->state = DEVICE_INVALID;           
        }
        
        return;
}

/** 
 * Find suitable driver for a device and assign the driver to it.
 * 
 * @param node the device node of the device in the device tree.
 * @param drivers_list the list of available drivers.
 * 
 * @return true if the suitable driver is found and successfully assigned to the device, false otherwise. 
 */
bool assign_driver(node_t *node, driver_list_t *drivers_list, dev_tree_t *tree) 
{
        //printf(NAME ": assign_driver\n");
        
        // find the driver which is the most suitable for handling this device
        driver_t *drv = find_best_match_driver(drivers_list, node);
        if (NULL == drv) {
                printf(NAME ": no driver found for device '%s'.\n", node->pathname); 
                return false;           
        }
        
        // attach the driver to the device
        attach_driver(node, drv);
        
        if (DRIVER_NOT_STARTED == drv->state) {
                // start driver
                start_driver(drv);
        } 
        
        if (DRIVER_RUNNING == drv->state) {
                // notify driver about new device
                int phone = ipc_connect_me_to(drv->phone, DRIVER_DEVMAN, 0, 0);
                if (phone > 0) {
                        add_device(phone, drv, node, tree);             
                        ipc_hangup(phone);
                }
        }
        
        return true;
}

/**
 * Initialize the device tree.
 * 
 * Create root device node of the tree and assign driver to it.
 * 
 * @param tree the device tree.
 * @param the list of available drivers.
 * @return true on success, false otherwise.
 */
bool init_device_tree(dev_tree_t *tree, driver_list_t *drivers_list)
{
        printf(NAME ": init_device_tree.\n");
        
        tree->current_handle = 0;
        
        hash_table_create(&tree->devman_devices, DEVICE_BUCKETS, 1, &devman_devices_ops);
        hash_table_create(&tree->devmap_devices, DEVICE_BUCKETS, 1, &devmap_devices_ops);
        
        fibril_rwlock_initialize(&tree->rwlock);
        
        // create root node and add it to the device tree
        if (!create_root_node(tree)) {
                return false;
        }

        // find suitable driver and start it
        return assign_driver(tree->root_node, drivers_list, tree);
}

/** Create and set device's full path in device tree.
 * 
 * @param node the device's device node.
 * @param parent the parent device node.
 * @return true on success, false otherwise (insufficient resources etc.). 
 */
static bool set_dev_path(node_t *node, node_t *parent)
{       
        assert(NULL != node->name);
        
        size_t pathsize = (str_size(node->name) + 1);   
        if (NULL != parent) {           
                pathsize += str_size(parent->pathname) + 1;             
        }
        
        if (NULL == (node->pathname = (char *)malloc(pathsize))) {
                printf(NAME ": failed to allocate device path.\n");
                return false;
        }
        
        if (NULL != parent) {
                str_cpy(node->pathname, pathsize, parent->pathname);
                str_append(node->pathname, pathsize, "/");
                str_append(node->pathname, pathsize, node->name);
        } else {
                str_cpy(node->pathname, pathsize, node->name);
        }
        
        return true;
}

/** Insert new device into device tree.
 * 
 * The device tree's rwlock should be already held exclusively when calling this function.
 * 
 * @param tree the device tree.
 * @param node the newly added device node. 
 * @param dev_name the name of the newly added device.
 * @param parent the parent device node.
 * @return true on success, false otherwise (insufficient resources etc.).
 */
bool insert_dev_node(dev_tree_t *tree, node_t *node, char *dev_name, node_t *parent)
{
        // printf(NAME ": insert_dev_node\n");
        
        assert(NULL != node && NULL != tree && NULL != dev_name);
        
        node->name = dev_name;
        if (!set_dev_path(node, parent)) {
                fibril_rwlock_write_unlock(&tree->rwlock);
                return false;           
        }
        
        // add the node to the handle-to-node map
        node->handle = ++tree->current_handle;
        unsigned long key = node->handle;
        hash_table_insert(&tree->devman_devices, &key, &node->devman_link);

        // add the node to the list of its parent's children
        node->parent = parent;
        if (NULL != parent) {
                list_append(&node->sibling, &parent->children);         
        }
        return true;
}

/** 
 * Find device node with a specified path in the device tree.
 * 
 * @param path the path of the device node in the device tree.
 * @param tree the device tree.
 * 
 * @return the device node if it is present in the tree, NULL otherwise.
 */
node_t * find_dev_node_by_path(dev_tree_t *tree, char *path)
{
        fibril_rwlock_read_lock(&tree->rwlock);
        
        node_t *dev = tree->root_node;
        // relative path to the device from its parent (but with '/' at the beginning)
        char *rel_path = path;
        char *next_path_elem = NULL;
        bool cont = '/' == rel_path[0];
        
        while (cont && NULL != dev) {           
                next_path_elem  = get_path_elem_end(rel_path + 1);              
                if ('/' == next_path_elem[0]) {
                        cont = true;
                        next_path_elem[0] = 0;
                } else {
                        cont = false;
                }
                
                dev = find_node_child(dev, rel_path + 1);               
                
                if (cont) {
                        // restore the original path
                        next_path_elem[0] = '/';
                }
                rel_path = next_path_elem;              
        }
        
        fibril_rwlock_read_unlock(&tree->rwlock);
        
        return dev;
}

/**
 * Find child device node with a specified name.
 * 
 * Device tree rwlock should be held at least for reading. 
 * 
 * @param parent the parent device node.
 * @param name the name of the child device node.
 * 
 * @return the child device node.
 */
node_t *find_node_child(node_t *parent, const char *name)
{
        node_t *dev;
        link_t *link;
                        
        link = parent->children.next;
        
        while (link != &parent->children) {
                dev = list_get_instance(link, node_t, sibling);
                
                if (0 == str_cmp(name, dev->name)) {
                        return dev;                     
                }
                
                link = link->next;
        }       
                
        return NULL;
}

/** Create unique device name within the class. 
 * 
 * @param cl the class.
 * @param base_dev_name contains base name for the device 
 * if it was specified by the driver when it registered the device by the class; 
 * NULL if driver specified no base name.
 * @return the unique name for the device within the class.
 */
char * create_dev_name_for_class(dev_class_t *cl, const char *base_dev_name)
{
        char *dev_name;
        const char *base_name;
        if (NULL != base_dev_name) {
                base_name = base_dev_name;
        } else {
                base_name = cl->base_dev_name;
        }
        
        size_t idx = get_new_class_dev_idx(cl);
        asprintf(&dev_name, "%s%d", base_name, idx);
        return dev_name;        
}

/** Add the device to the class.
 * 
 * The device may be added to multiple classes and a class may contain multiple devices.
 * The class and the device are associated with each other by the dev_class_info_t structure.
 * 
 * @param dev the device.
 * @param class the class.
 * @param base_dev_name the base name of the device within the class if specified by the driver,
 * NULL otherwise.
 * @return dev_class_info_t structure which associates the device with the class.
 */
dev_class_info_t * add_device_to_class(node_t *dev, dev_class_t *cl, const char *base_dev_name)
{       
        dev_class_info_t *info = create_dev_class_info();
        if (NULL != info) {
                info->dev_class = cl;
                info->dev = dev;
                
                // add the device to the class
                fibril_mutex_lock(&cl->mutex);
                list_append(&info->link, &cl->devices);
                fibril_mutex_unlock(&cl->mutex);
                
                // add the class to the device
                list_append(&info->dev_classes, &dev->classes);
                
                // create unique name for the device within the class
                info->dev_name = create_dev_name_for_class(cl, base_dev_name);  
        }
        
        return info;
}

dev_class_t * get_dev_class(class_list_t *class_list, char *class_name)
{
        dev_class_t *cl;
        fibril_rwlock_write_lock(&class_list->rwlock);  
        cl = find_dev_class_no_lock(class_list, class_name);
        if (NULL == cl) {
                cl = create_dev_class();
                if (NULL != cl) {
                        cl->name = class_name;  
                        cl->base_dev_name = "";
                        add_dev_class_no_lock(class_list, cl);
                }               
        }       
        fibril_rwlock_write_unlock(&class_list->rwlock);
        return cl;
}

dev_class_t * find_dev_class_no_lock(class_list_t *class_list, const char *class_name)
{
        dev_class_t *cl;
        link_t *link = class_list->classes.next;
        while (link != &class_list->classes) {
                cl = list_get_instance(link, dev_class_t, link);
                if (0 == str_cmp(cl->name, class_name)) {
                        return cl;
                }
        }
        
        return NULL;    
}

void init_class_list(class_list_t *class_list)
{
        list_initialize(&class_list->classes);
        fibril_rwlock_initialize(&class_list->rwlock);
        hash_table_create(&class_list->devmap_devices, DEVICE_BUCKETS, 1, &devmap_devices_ops); 
}


// devmap devices

node_t *find_devmap_tree_device(dev_tree_t *tree, dev_handle_t devmap_handle)
{
        node_t *dev = NULL;
        link_t *link;
        unsigned long key = (unsigned long)devmap_handle;
        
        fibril_rwlock_read_lock(&tree->rwlock);
        link = hash_table_find(&tree->devmap_devices, &key);    
        if (NULL != link) {
                dev = hash_table_get_instance(link, node_t, devmap_link);
        }
        fibril_rwlock_read_unlock(&tree->rwlock);
        
        return dev;
}

node_t *find_devmap_class_device(class_list_t *classes, dev_handle_t devmap_handle)
{
        node_t *dev = NULL;
        dev_class_info_t *cli;
        link_t *link;
        unsigned long key = (unsigned long)devmap_handle;
        
        fibril_rwlock_read_lock(&classes->rwlock);
        link = hash_table_find(&classes->devmap_devices, &key); 
        if (NULL != link) {
                cli = hash_table_get_instance(link, dev_class_info_t, devmap_link);
                dev = cli->dev;
        }
        fibril_rwlock_read_unlock(&classes->rwlock);
        
        return dev;     
}


/** @}
 */