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/************************************************************************************
* drivers/serialirq.c
*
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
************************************************************************************/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <semaphore.h>
#include <debug.h>
#include <nuttx/serial.h>
/************************************************************************************
* Definitions
************************************************************************************/
/************************************************************************************
* Private Types
************************************************************************************/
/************************************************************************************
* Private Function Prototypes
************************************************************************************/
/************************************************************************************
* Private Variables
************************************************************************************/
/************************************************************************************
* Private Functions
************************************************************************************/
/************************************************************************************
* Public Functions
************************************************************************************/
/************************************************************************************
* Name: uart_xmitchars
*
* Description:
* This function is called from the UART interrupt handler when an interrupt
* is received indicating that there is more space in the transmit FIFO. This
* function will send characters from the tail of the xmit buffer while the driver
* write() logic adds data to the head of the xmit buffer.
*
************************************************************************************/
void uart_xmitchars(FAR uart_dev_t *dev)
{
/* Send while we still have data & room in the fifo */
while (dev->xmit.head != dev->xmit.tail && uart_txready(dev))
{
/* Send the next byte */
uart_send(dev, dev->xmit.buffer[dev->xmit.tail]);
/* Increment the tail index */
if (++(dev->xmit.tail) >= dev->xmit.size)
{
dev->xmit.tail = 0;
}
/* A byte was removed from the buffer. Inform any waiters
* there there is space available.
*/
if (dev->xmitwaiting)
{
dev->xmitwaiting = FALSE;
(void)sem_post(&dev->xmitsem);
}
}
/* When all of the characters have been sent from the buffer
* disable the TX interrupt.
*/
if (dev->xmit.head == dev->xmit.tail)
{
uart_disabletxint(dev);
}
}
/************************************************************************************
* Name: uart_receivechars
*
* Description:
* This function is called from the UART interrupt handler when an interrupt
* is received indicating that are bytes available in the receive fifo. This
* function will add chars to head of receive buffer. Driver read() logic will take
* characters from the tail of the buffer.
*
************************************************************************************/
void uart_recvchars(FAR uart_dev_t *dev)
{
unsigned int status;
int nexthead = dev->recv.head + 1;
if (nexthead >= dev->recv.size)
{
nexthead = 0;
}
/* Loop putting characters into the receive buffer until eithe: (1) the buffer
* is full, or (2) there are not further characters to add.
*/
while (nexthead != dev->recv.tail && uart_rxavailable(dev))
{
/* Add the character to the buffer */
dev->recv.buffer[dev->recv.head] = uart_receive(dev, &status);
/* Increment the head index */
dev->recv.head = nexthead;
if (++nexthead >= dev->recv.size)
{
nexthead = 0;
}
/* A character was added... if there is a thread waiting for more data, then
* post the recvsem semaphore to wake it up. NOTE: There is a logic error in
* the above looping logic: If nexthead == dev->recv.tail on entry and
* recvwaiting is true, the recvsem will never get posted!
*/
if (dev->recvwaiting)
{
dev->recvwaiting = FALSE;
(void)sem_post(&dev->recvsem);
}
}
}
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