source: mainline/uspace/lib/drv/generic/remote_char_dev.c@ 68414f4a

/*
 * 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 libdrv
 * @{
 */
/** @file
 */

#include <async.h>
#include <errno.h>

#include "ops/char_dev.h"
#include "driver.h"

#define MAX_CHAR_RW_COUNT 256

static void remote_char_read(function_t *, void *, ipc_callid_t, ipc_call_t *);
static void remote_char_write(function_t *, void *, ipc_callid_t, ipc_call_t *);

/** Remote character interface operations. */
static remote_iface_func_ptr_t remote_char_dev_iface_ops[] = {
        &remote_char_read,
        &remote_char_write
};

/** Remote character interface structure.
 *
 * Interface for processing request from remote clients addressed to the
 * character interface.
 */
remote_iface_t remote_char_dev_iface = {
        .method_count = sizeof(remote_char_dev_iface_ops) /
            sizeof(remote_iface_func_ptr_t),
        .methods = remote_char_dev_iface_ops
};

/** Process the read request from the remote client.
 *
 * Receive the read request's parameters from the remote client and pass them
 * to the local interface. Return the result of the operation processed by the
 * local interface to the remote client.
 *
 * @param fun           The function from which the data are read.
 * @param ops           The local ops structure.
 */
static void
remote_char_read(function_t *fun, void *ops, ipc_callid_t callid,
    ipc_call_t *call)
{
        char_dev_ops_t *char_dev_ops = (char_dev_ops_t *) ops;
        ipc_callid_t cid;
        
        size_t len;
        if (!async_data_read_receive(&cid, &len)) {
                /* TODO handle protocol error. */
                async_answer_0(callid, EINVAL);
                return;
        }
        
        if (!char_dev_ops->read) {
                async_data_read_finalize(cid, NULL, 0);
                async_answer_0(callid, ENOTSUP);
                return;
        }
        
        if (len > MAX_CHAR_RW_COUNT)
                len = MAX_CHAR_RW_COUNT;
        
        char buf[MAX_CHAR_RW_COUNT];
        int ret = (*char_dev_ops->read)(fun, buf, len);
        
        if (ret < 0) {
                /* Some error occured. */
                async_data_read_finalize(cid, buf, 0);
                async_answer_0(callid, ret);
                return;
        }
        
        /* The operation was successful, return the number of data read. */
        async_data_read_finalize(cid, buf, ret);
        async_answer_1(callid, EOK, ret);
}

/** Process the write request from the remote client.
 *
 * Receive the write request's parameters from the remote client and pass them
 * to the local interface. Return the result of the operation processed by the
 * local interface to the remote client.
 *
 * @param fun           The function to which the data are written.
 * @param ops           The local ops structure.
 */
static void
remote_char_write(function_t *fun, void *ops, ipc_callid_t callid,
    ipc_call_t *call)
{
        char_dev_ops_t *char_dev_ops = (char_dev_ops_t *) ops;
        ipc_callid_t cid;
        size_t len;
        
        if (!async_data_write_receive(&cid, &len)) {
                /* TODO handle protocol error. */
                async_answer_0(callid, EINVAL);
                return;
        }
        
        if (!char_dev_ops->write) {
                async_data_write_finalize(cid, NULL, 0);
                async_answer_0(callid, ENOTSUP);
                return;
        }
        
        if (len > MAX_CHAR_RW_COUNT)
                len = MAX_CHAR_RW_COUNT;
        
        char buf[MAX_CHAR_RW_COUNT];
        
        async_data_write_finalize(cid, buf, len);
        
        int ret = (*char_dev_ops->write)(fun, buf, len);
        if (ret < 0) {
                /* Some error occured. */
                async_answer_0(callid, ret);
        } else {
                /*
                 * The operation was successful, return the number of data
                 * written.
                 */
                async_answer_1(callid, EOK, ret);
        }
}

/**
 * @}
 */