source: mainline/uspace/lib/c/generic/device/char.c@ aaa3f33a

/*
 * 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 libc
 * @{
 */
/** @file
 */

#include <ipc/dev_iface.h>
#include <device/char.h>
#include <errno.h>
#include <async.h>
#include <malloc.h>
#include <stdio.h>

/** Read to or write from the device using its character interface.
 * 
 * Helper function.
 * 
 * @param dev_phone phone to the device.
 * @param buf the buffer for the data read from or written to the device.
 * @param len the maximum length of the data to be read or written.
 * @param read read from the device if true, write to it otherwise.
 * 
 * @return non-negative number of bytes actually read from or written to the device on success,
 * negative error number otherwise.
 * 
 */
static int rw_dev(int dev_phone, void *buf, size_t len, bool read) 
{
        ipc_call_t answer;
        
        async_serialize_start();
        
        aid_t req;
        int ret;
        
        if (read) {
                req = async_send_1(dev_phone, DEV_IFACE_ID(CHAR_DEV_IFACE), CHAR_READ_DEV, &answer);
                ret = async_data_read_start(dev_phone, buf, len);               
        } else {
                req = async_send_1(dev_phone, DEV_IFACE_ID(CHAR_DEV_IFACE), CHAR_WRITE_DEV, &answer);
                ret = async_data_write_start(dev_phone, buf, len);
        }
        
        ipcarg_t rc;
        if (ret != EOK) {               
                async_wait_for(req, &rc);
                async_serialize_end();
                if (rc == EOK) {
                        return ret;
                }
                else {
                        return (int) rc;
                }
        }
        
        async_wait_for(req, &rc);
        async_serialize_end();
        
        ret = (int)rc;
        if (EOK != ret) {
                return ret;
        }
        
        return IPC_GET_ARG1(answer);    
}

/** Read from the device using its character interface.
 * 
 * @param dev_phone phone to the device.
 * @param buf the output buffer for the data read from the device.
 * @param len the maximum length of the data to be read.
 * 
 * @return non-negative number of bytes actually read from the device on success, negative error number otherwise.
 */
int read_dev(int dev_phone, void *buf, size_t len)
{       
        return rw_dev(dev_phone, buf, len, true);
}

/** Write to the device using its character interface.
 * 
 * @param dev_phone phone to the device.
 * @param buf the input buffer containg the data to be written to the device.
 * @param len the maximum length of the data to be written.
 * 
 * @return non-negative number of bytes actually written to the device on success, negative error number otherwise.
 */
int write_dev(int dev_phone, void *buf, size_t len)
{
        return rw_dev(dev_phone, buf, len, false);
}

  
 /** @}
 */