source: mainline/uspace/lib/drv/generic/driver.c@ 9624c35

/*
 * Copyright (c) 2010 Lenka Trochtova
 * Copyright (c) 2011 Jiri Svoboda
 * 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.
 */

/**
 * @defgroup libdrv generic device driver support.
 * @brief HelenOS generic device driver support.
 * @{
 */

/** @file
 */

#include <assert.h>
#include <ipc/services.h>
#include <ipc/ns.h>
#include <async.h>
#include <stdio.h>
#include <errno.h>
#include <stdbool.h>
#include <fibril_synch.h>
#include <stdlib.h>
#include <str.h>
#include <str_error.h>
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <devman.h>

#include <ipc/driver.h>

#include "dev_iface.h"
#include "ddf/driver.h"
#include "ddf/interrupt.h"
#include "private/driver.h"

/** Driver structure */
static const driver_t *driver;

/** Devices */
LIST_INITIALIZE(devices);
FIBRIL_MUTEX_INITIALIZE(devices_mutex);

/** Functions */
LIST_INITIALIZE(functions);
FIBRIL_MUTEX_INITIALIZE(functions_mutex);

static ddf_dev_t *create_device(void);
static void delete_device(ddf_dev_t *);
static void dev_add_ref(ddf_dev_t *);
static void dev_del_ref(ddf_dev_t *);
static void fun_add_ref(ddf_fun_t *);
static void fun_del_ref(ddf_fun_t *);
static remote_handler_t *function_get_default_handler(ddf_fun_t *);
static void *function_get_ops(ddf_fun_t *, dev_inferface_idx_t);

static void add_to_functions_list(ddf_fun_t *fun)
{
        fibril_mutex_lock(&functions_mutex);
        list_append(&fun->link, &functions);
        fibril_mutex_unlock(&functions_mutex);
}

static void remove_from_functions_list(ddf_fun_t *fun)
{
        fibril_mutex_lock(&functions_mutex);
        list_remove(&fun->link);
        fibril_mutex_unlock(&functions_mutex);
}

static ddf_dev_t *driver_get_device(devman_handle_t handle)
{
        assert(fibril_mutex_is_locked(&devices_mutex));
        
        list_foreach(devices, link, ddf_dev_t, dev) {
                if (dev->handle == handle)
                        return dev;
        }
        
        return NULL;
}

static ddf_fun_t *driver_get_function(devman_handle_t handle)
{
        assert(fibril_mutex_is_locked(&functions_mutex));
        
        list_foreach(functions, link, ddf_fun_t, fun) {
                if (fun->handle == handle)
                        return fun;
        }
        
        return NULL;
}

static void driver_dev_add(ipc_callid_t iid, ipc_call_t *icall)
{
        devman_handle_t dev_handle = IPC_GET_ARG1(*icall);
        devman_handle_t parent_fun_handle = IPC_GET_ARG2(*icall);
        
        ddf_dev_t *dev = create_device();
        
        /* Add one reference that will be dropped by driver_dev_remove() */
        dev_add_ref(dev);
        dev->handle = dev_handle;
        
        char *dev_name = NULL;
        async_data_write_accept((void **) &dev_name, true, 0, 0, 0, 0);
        dev->name = dev_name;
        
        /*
         * Currently not used, parent fun handle is stored in context
         * of the connection to the parent device driver.
         */
        (void) parent_fun_handle;
        
        int res = driver->driver_ops->dev_add(dev);
        
        if (res != EOK) {
                dev_del_ref(dev);
                async_answer_0(iid, res);
                return;
        }
        
        fibril_mutex_lock(&devices_mutex);
        list_append(&dev->link, &devices);
        fibril_mutex_unlock(&devices_mutex);
        
        async_answer_0(iid, res);
}

static void driver_dev_remove(ipc_callid_t iid, ipc_call_t *icall)
{
        devman_handle_t devh = IPC_GET_ARG1(*icall);
        
        fibril_mutex_lock(&devices_mutex);
        ddf_dev_t *dev = driver_get_device(devh);
        if (dev != NULL)
                dev_add_ref(dev);
        fibril_mutex_unlock(&devices_mutex);
        
        if (dev == NULL) {
                async_answer_0(iid, ENOENT);
                return;
        }
        
        int rc;
        
        if (driver->driver_ops->dev_remove != NULL)
                rc = driver->driver_ops->dev_remove(dev);
        else
                rc = ENOTSUP;
        
        if (rc == EOK)
                dev_del_ref(dev);
        
        async_answer_0(iid, (sysarg_t) rc);
}

static void driver_dev_gone(ipc_callid_t iid, ipc_call_t *icall)
{
        devman_handle_t devh = IPC_GET_ARG1(*icall);
        
        fibril_mutex_lock(&devices_mutex);
        ddf_dev_t *dev = driver_get_device(devh);
        if (dev != NULL)
                dev_add_ref(dev);
        fibril_mutex_unlock(&devices_mutex);
        
        if (dev == NULL) {
                async_answer_0(iid, ENOENT);
                return;
        }
        
        int rc;
        
        if (driver->driver_ops->dev_gone != NULL)
                rc = driver->driver_ops->dev_gone(dev);
        else
                rc = ENOTSUP;
        
        if (rc == EOK)
                dev_del_ref(dev);
        
        async_answer_0(iid, (sysarg_t) rc);
}

static void driver_fun_online(ipc_callid_t iid, ipc_call_t *icall)
{
        devman_handle_t funh = IPC_GET_ARG1(*icall);
        
        /*
         * Look the function up. Bump reference count so that
         * the function continues to exist until we return
         * from the driver.
         */
        fibril_mutex_lock(&functions_mutex);
        
        ddf_fun_t *fun = driver_get_function(funh);
        if (fun != NULL)
                fun_add_ref(fun);
        
        fibril_mutex_unlock(&functions_mutex);
        
        if (fun == NULL) {
                async_answer_0(iid, ENOENT);
                return;
        }
        
        /* Call driver entry point */
        int rc;
        
        if (driver->driver_ops->fun_online != NULL)
                rc = driver->driver_ops->fun_online(fun);
        else
                rc = ENOTSUP;
        
        fun_del_ref(fun);
        
        async_answer_0(iid, (sysarg_t) rc);
}

static void driver_fun_offline(ipc_callid_t iid, ipc_call_t *icall)
{
        devman_handle_t funh = IPC_GET_ARG1(*icall);
        
        /*
         * Look the function up. Bump reference count so that
         * the function continues to exist until we return
         * from the driver.
         */
        fibril_mutex_lock(&functions_mutex);
        
        ddf_fun_t *fun = driver_get_function(funh);
        if (fun != NULL)
                fun_add_ref(fun);
        
        fibril_mutex_unlock(&functions_mutex);
        
        if (fun == NULL) {
                async_answer_0(iid, ENOENT);
                return;
        }
        
        /* Call driver entry point */
        int rc;
        
        if (driver->driver_ops->fun_offline != NULL)
                rc = driver->driver_ops->fun_offline(fun);
        else
                rc = ENOTSUP;
        
        async_answer_0(iid, (sysarg_t) rc);
}

static void driver_connection_devman(ipc_callid_t iid, ipc_call_t *icall)
{
        /* Accept connection */
        async_answer_0(iid, EOK);
        
        while (true) {
                ipc_call_t call;
                ipc_callid_t callid = async_get_call(&call);
                
                if (!IPC_GET_IMETHOD(call))
                        break;
                
                switch (IPC_GET_IMETHOD(call)) {
                case DRIVER_DEV_ADD:
                        driver_dev_add(callid, &call);
                        break;
                case DRIVER_DEV_REMOVE:
                        driver_dev_remove(callid, &call);
                        break;
                case DRIVER_DEV_GONE:
                        driver_dev_gone(callid, &call);
                        break;
                case DRIVER_FUN_ONLINE:
                        driver_fun_online(callid, &call);
                        break;
                case DRIVER_FUN_OFFLINE:
                        driver_fun_offline(callid, &call);
                        break;
                default:
                        async_answer_0(callid, ENOTSUP);
                }
        }
}

/** Generic client connection handler both for applications and drivers.
 *
 * @param drv True for driver client, false for other clients
 *            (applications, services, etc.).
 *
 */
static void driver_connection_gen(ipc_callid_t iid, ipc_call_t *icall, bool drv)
{
        /*
         * Answer the first IPC_M_CONNECT_ME_TO call and remember the handle of
         * the device to which the client connected.
         */
        devman_handle_t handle = IPC_GET_ARG2(*icall);

        fibril_mutex_lock(&functions_mutex);
        ddf_fun_t *fun = driver_get_function(handle);
        fibril_mutex_unlock(&functions_mutex);
        /* XXX Need a lock on fun */
        
        if (fun == NULL) {
                printf("%s: driver_connection_gen error - no function with handle"
                    " %" PRIun " was found.\n", driver->name, handle);
                async_answer_0(iid, ENOENT);
                return;
        }
        
        if (fun->conn_handler != NULL) {
                /* Driver has a custom connection handler. */
                (*fun->conn_handler)(iid, icall, (void *)fun);
                return;
        }
        
        /*
         * TODO - if the client is not a driver, check whether it is allowed to
         * use the device.
         */
        
        int ret = EOK;
        /* Open device function */
        if (fun->ops != NULL && fun->ops->open != NULL)
                ret = (*fun->ops->open)(fun);
        
        async_answer_0(iid, ret);
        if (ret != EOK)
                return;
        
        while (true) {
                ipc_callid_t callid;
                ipc_call_t call;
                callid = async_get_call(&call);
                sysarg_t method = IPC_GET_IMETHOD(call);
                
                if (!method) {
                        /* Close device function */
                        if (fun->ops != NULL && fun->ops->close != NULL)
                                (*fun->ops->close)(fun);
                        async_answer_0(callid, EOK);
                        return;
                }
                
                /* Convert ipc interface id to interface index */
                
                int iface_idx = DEV_IFACE_IDX(method);
                
                if (!is_valid_iface_idx(iface_idx)) {
                        remote_handler_t *default_handler =
                            function_get_default_handler(fun);
                        if (default_handler != NULL) {
                                (*default_handler)(fun, callid, &call);
                                continue;
                        }
                        
                        /*
                         * Function has no such interface and
                         * default handler is not provided.
                         */
                        printf("%s: driver_connection_gen error - "
                            "invalid interface id %d.",
                            driver->name, iface_idx);
                        async_answer_0(callid, ENOTSUP);
                        continue;
                }
                
                /* Calling one of the function's interfaces */
                
                /* Get the interface ops structure. */
                void *ops = function_get_ops(fun, iface_idx);
                if (ops == NULL) {
                        printf("%s: driver_connection_gen error - ", driver->name);
                        printf("Function with handle %" PRIun " has no interface "
                            "with id %d.\n", handle, iface_idx);
                        async_answer_0(callid, ENOTSUP);
                        continue;
                }
                
                /*
                 * Get the corresponding interface for remote request
                 * handling ("remote interface").
                 */
                const remote_iface_t *rem_iface = get_remote_iface(iface_idx);
                assert(rem_iface != NULL);
                
                /* get the method of the remote interface */
                sysarg_t iface_method_idx = IPC_GET_ARG1(call);
                remote_iface_func_ptr_t iface_method_ptr =
                    get_remote_method(rem_iface, iface_method_idx);
                if (iface_method_ptr == NULL) {
                        /* The interface has not such method */
                        printf("%s: driver_connection_gen error - "
                            "invalid interface method.", driver->name);
                        async_answer_0(callid, ENOTSUP);
                        continue;
                }
                
                /*
                 * Call the remote interface's method, which will
                 * receive parameters from the remote client and it will
                 * pass it to the corresponding local interface method
                 * associated with the function by its driver.
                 */
                (*iface_method_ptr)(fun, ops, callid, &call);
        }
}

static void driver_connection_driver(ipc_callid_t iid, ipc_call_t *icall)
{
        driver_connection_gen(iid, icall, true);
}

static void driver_connection_client(ipc_callid_t iid, ipc_call_t *icall)
{
        driver_connection_gen(iid, icall, false);
}

/** Function for handling connections to device driver. */
static void driver_connection(ipc_callid_t iid, ipc_call_t *icall, void *arg)
{
        sysarg_t conn_type;

        if (iid == 0) {
                /* Callback connection from devman */
                /* XXX Use separate handler for this type of connection */
                conn_type = DRIVER_DEVMAN;
        } else {
                conn_type = IPC_GET_ARG1(*icall);
        }

        /* Select interface */
        switch (conn_type) {
        case DRIVER_DEVMAN:
                /* Handle request from device manager */
                driver_connection_devman(iid, icall);
                break;
        case DRIVER_DRIVER:
                /* Handle request from drivers of child devices */
                driver_connection_driver(iid, icall);
                break;
        case DRIVER_CLIENT:
                /* Handle request from client applications */
                driver_connection_client(iid, icall);
                break;
        default:
                /* No such interface */
                async_answer_0(iid, ENOENT);
        }
}

/** Create new device structure.
 *
 * @return              The device structure.
 */
static ddf_dev_t *create_device(void)
{
        ddf_dev_t *dev;

        dev = calloc(1, sizeof(ddf_dev_t));
        if (dev == NULL)
                return NULL;

        return dev;
}

/** Create new function structure.
 *
 * @return              The device structure.
 */
static ddf_fun_t *create_function(void)
{
        ddf_fun_t *fun;

        fun = calloc(1, sizeof(ddf_fun_t));
        if (fun == NULL)
                return NULL;

        init_match_ids(&fun->match_ids);
        link_initialize(&fun->link);

        return fun;
}

/** Delete device structure.
 *
 * @param dev           The device structure.
 */
static void delete_device(ddf_dev_t *dev)
{
        if (dev->parent_sess)
                async_hangup(dev->parent_sess);
        if (dev->driver_data != NULL)
                free(dev->driver_data);
        free(dev);
}

/** Delete function structure.
 *
 * @param dev           The device structure.
 */
static void delete_function(ddf_fun_t *fun)
{
        clean_match_ids(&fun->match_ids);
        if (fun->driver_data != NULL)
                free(fun->driver_data);
        if (fun->name != NULL)
                free(fun->name);
        free(fun);
}

/** Increase device reference count. */
static void dev_add_ref(ddf_dev_t *dev)
{
        atomic_inc(&dev->refcnt);
}

/** Decrease device reference count.
 *
 * Free the device structure if the reference count drops to zero.
 */
static void dev_del_ref(ddf_dev_t *dev)
{
        if (atomic_predec(&dev->refcnt) == 0)
                delete_device(dev);
}

/** Increase function reference count.
 *
 * This also increases reference count on the device. The device structure
 * will thus not be deallocated while there are some associated function
 * structures.
 */
static void fun_add_ref(ddf_fun_t *fun)
{
        dev_add_ref(fun->dev);
        atomic_inc(&fun->refcnt);
}

/** Decrease function reference count.
 *
 * Free the function structure if the reference count drops to zero.
 */
static void fun_del_ref(ddf_fun_t *fun)
{
        ddf_dev_t *dev = fun->dev;

        if (atomic_predec(&fun->refcnt) == 0)
                delete_function(fun);

        dev_del_ref(dev);
}

/** Allocate driver-specific device data. */
void *ddf_dev_data_alloc(ddf_dev_t *dev, size_t size)
{
        assert(dev->driver_data == NULL);
        
        void *data = calloc(1, size);
        if (data == NULL)
                return NULL;
        
        dev->driver_data = data;
        return data;
}

/** Return driver-specific device data. */
void *ddf_dev_data_get(ddf_dev_t *dev)
{
        return dev->driver_data;
}

/** Get device handle. */
devman_handle_t ddf_dev_get_handle(ddf_dev_t *dev)
{
        return dev->handle;
}

/** Return device name.
 *
 * @param dev   Device
 * @return      Device name. Valid as long as @a dev is valid.
 */
const char *ddf_dev_get_name(ddf_dev_t *dev)
{
        return dev->name;
}

/** Create session with the parent function.
 *
 * The session will be automatically closed when @a dev is destroyed.
 *
 * @param dev   Device
 * @param mgmt  Exchange management style
 * @return      New session or NULL if session could not be created
 */
async_sess_t *ddf_dev_parent_sess_create(ddf_dev_t *dev, exch_mgmt_t mgmt)
{
        assert(dev->parent_sess == NULL);
        dev->parent_sess = devman_parent_device_connect(mgmt, dev->handle,
            IPC_FLAG_BLOCKING);

        return dev->parent_sess;
}

/** Return existing session with the parent function.
 *
 * @param dev   Device
 * @return      Existing session or NULL if there is no session
 */
async_sess_t *ddf_dev_parent_sess_get(ddf_dev_t *dev)
{
        return dev->parent_sess;
}

/** Set function name (if it was not specified when node was created.)
 *
 * @param dev   Device whose name has not been set yet
 * @param name  Name, will be copied
 * @return      EOK on success, ENOMEM if out of memory
 */
int ddf_fun_set_name(ddf_fun_t *dev, const char *name)
{
        assert(dev->name == NULL);

        dev->name = str_dup(name);
        if (dev->name == NULL)
                return ENOENT;

        return EOK;
}

/** Get device to which function belongs. */
ddf_dev_t *ddf_fun_get_dev(ddf_fun_t *fun)
{
        return fun->dev;
}

/** Get function handle.
 *
 * XXX USB uses this, but its use should be eliminated.
 */
devman_handle_t ddf_fun_get_handle(ddf_fun_t *fun)
{
        return fun->handle;
}

/** Create a DDF function node.
 *
 * Create a DDF function (in memory). Both child devices and external clients
 * communicate with a device via its functions.
 *
 * The created function node is fully formed, but only exists in the memory
 * of the client task. In order to be visible to the system, the function
 * must be bound using ddf_fun_bind().
 *
 * This function should only fail if there is not enough free memory.
 * Specifically, this function succeeds even if @a dev already has
 * a (bound) function with the same name. @a name can be NULL in which
 * case the caller will set the name later using ddf_fun_set_name().
 * He must do this before binding the function.
 *
 * Type: A function of type fun_inner indicates that DDF should attempt
 * to attach child devices to the function. fun_exposed means that
 * the function should be exported to external clients (applications).
 *
 * @param dev           Device to which we are adding function
 * @param ftype         Type of function (fun_inner or fun_exposed)
 * @param name          Name of function or NULL
 *
 * @return              New function or @c NULL if memory is not available
 */
ddf_fun_t *ddf_fun_create(ddf_dev_t *dev, fun_type_t ftype, const char *name)
{
        ddf_fun_t *fun = create_function();
        if (fun == NULL)
                return NULL;
        
        /* Add one reference that will be dropped by ddf_fun_destroy() */
        fun->dev = dev;
        fun_add_ref(fun);
        
        fun->bound = false;
        fun->ftype = ftype;
        
        if (name != NULL) {
                fun->name = str_dup(name);
                if (fun->name == NULL) {
                        delete_function(fun);
                        return NULL;
                }
        }
        
        return fun;
}

/** Allocate driver-specific function data. */
void *ddf_fun_data_alloc(ddf_fun_t *fun, size_t size)
{
        assert(fun->bound == false);
        assert(fun->driver_data == NULL);
        
        void *data = calloc(1, size);
        if (data == NULL)
                return NULL;
        
        fun->driver_data = data;
        return data;
}

/** Return driver-specific function data. */
void *ddf_fun_data_get(ddf_fun_t *fun)
{
        return fun->driver_data;
}

/** Return function name.
 *
 * @param fun   Function
 * @return      Function name. Valid as long as @a fun is valid.
 */
const char *ddf_fun_get_name(ddf_fun_t *fun)
{
        return fun->name;
}

/** Destroy DDF function node.
 *
 * Destroy a function previously created with ddf_fun_create(). The function
 * must not be bound.
 *
 * @param fun Function to destroy
 *
 */
void ddf_fun_destroy(ddf_fun_t *fun)
{
        assert(fun->bound == false);
        
        /*
         * Drop the reference added by ddf_fun_create(). This will deallocate
         * the function as soon as all other references are dropped (i.e.
         * as soon control leaves all driver entry points called in context
         * of this function.
         */
        fun_del_ref(fun);
}

static void *function_get_ops(ddf_fun_t *fun, dev_inferface_idx_t idx)
{
        assert(is_valid_iface_idx(idx));
        if (fun->ops == NULL)
                return NULL;
        
        return fun->ops->interfaces[idx];
}

/** Bind a function node.
 *
 * Bind the specified function to the system. This effectively makes
 * the function visible to the system (uploads it to the server).
 *
 * This function can fail for several reasons. Specifically,
 * it will fail if the device already has a bound function of
 * the same name.
 *
 * @param fun Function to bind
 *
 * @return EOK on success or negative error code
 *
 */
int ddf_fun_bind(ddf_fun_t *fun)
{
        assert(fun->bound == false);
        assert(fun->name != NULL);
        
        add_to_functions_list(fun);
        int res = devman_add_function(fun->name, fun->ftype, &fun->match_ids,
            fun->dev->handle, &fun->handle);
        if (res != EOK) {
                remove_from_functions_list(fun);
                return res;
        }
        
        fun->bound = true;
        return res;
}

/** Unbind a function node.
 *
 * Unbind the specified function from the system. This effectively makes
 * the function invisible to the system.
 *
 * @param fun Function to unbind
 *
 * @return EOK on success or negative error code
 *
 */
int ddf_fun_unbind(ddf_fun_t *fun)
{
        assert(fun->bound == true);
        
        int res = devman_remove_function(fun->handle);
        if (res != EOK)
                return res;
        
        remove_from_functions_list(fun);
        
        fun->bound = false;
        return EOK;
}

/** Online function.
 *
 * @param fun Function to online
 *
 * @return EOK on success or negative error code
 *
 */
int ddf_fun_online(ddf_fun_t *fun)
{
        assert(fun->bound == true);
        
        int res = devman_drv_fun_online(fun->handle);
        if (res != EOK)
                return res;
        
        return EOK;
}

/** Offline function.
 *
 * @param fun Function to offline
 *
 * @return EOK on success or negative error code
 *
 */
int ddf_fun_offline(ddf_fun_t *fun)
{
        assert(fun->bound == true);
        
        int res = devman_drv_fun_offline(fun->handle);
        if (res != EOK)
                return res;
        
        return EOK;
}

/** Add single match ID to inner function.
 *
 * Construct and add a single match ID to the specified function.
 * Cannot be called when the function node is bound.
 *
 * @param fun          Function
 * @param match_id_str Match string
 * @param match_score  Match score
 *
 * @return EOK on success.
 * @return ENOMEM if out of memory.
 *
 */
int ddf_fun_add_match_id(ddf_fun_t *fun, const char *match_id_str,
    int match_score)
{
        assert(fun->bound == false);
        assert(fun->ftype == fun_inner);
        
        match_id_t *match_id = create_match_id();
        if (match_id == NULL)
                return ENOMEM;
        
        match_id->id = str_dup(match_id_str);
        match_id->score = match_score;
        
        add_match_id(&fun->match_ids, match_id);
        return EOK;
}

/** Set function ops. */
void ddf_fun_set_ops(ddf_fun_t *fun, ddf_dev_ops_t *dev_ops)
{
        assert(fun->conn_handler == NULL);
        fun->ops = dev_ops;
}

/** Set user-defined connection handler.
 *
 * This allows handling connections the non-devman way.
 */
void ddf_fun_set_conn_handler(ddf_fun_t *fun, async_client_conn_t conn)
{
        assert(fun->ops == NULL);
        fun->conn_handler = conn;
}

/** Get default handler for client requests */
static remote_handler_t *function_get_default_handler(ddf_fun_t *fun)
{
        if (fun->ops == NULL)
                return NULL;
        return fun->ops->default_handler;
}

/** Add exposed function to category.
 *
 * Must only be called when the function is bound.
 *
 */
int ddf_fun_add_to_category(ddf_fun_t *fun, const char *cat_name)
{
        assert(fun->bound == true);
        assert(fun->ftype == fun_exposed);
        
        return devman_add_device_to_category(fun->handle, cat_name);
}

int ddf_driver_main(const driver_t *drv)
{
        /*
         * Remember the driver structure - driver_ops will be called by generic
         * handler for incoming connections.
         */
        driver = drv;
        
        /*
         * Register driver with device manager using generic handler for
         * incoming connections.
         */
        async_set_client_connection(driver_connection);
        int rc = devman_driver_register(driver->name);
        if (rc != EOK) {
                printf("Error: Failed to register driver with device manager "
                    "(%s).\n", (rc == EEXISTS) ? "driver already started" :
                    str_error(rc));
                
                return rc;
        }
        
        /* Return success from the task since server has started. */
        rc = task_retval(0);
        if (rc != EOK)
                return rc;
        
        async_manager();
        
        /* Never reached. */
        return EOK;
}

/**
 * @}
 */