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incubator-nuttx/graphics/nxterm/nxterm_kbdin.c

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/****************************************************************************
* graphics/nxterm/nxterm_kbdin.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <inttypes.h>
#include <fcntl.h>
#include <sched.h>
#include <assert.h>
#include <poll.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include "nxterm.h"
#ifdef CONFIG_NXTERM_NXKBDIN
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nxterm_pollnotify
****************************************************************************/
static void nxterm_pollnotify(FAR struct nxterm_state_s *priv,
pollevent_t eventset)
{
FAR struct pollfd *fds;
irqstate_t flags;
int i;
/* This function may be called from an interrupt handler */
for (i = 0; i < CONFIG_NXTERM_NPOLLWAITERS; i++)
{
flags = enter_critical_section();
fds = priv->fds[i];
if (fds)
{
fds->revents |= (fds->events & eventset);
if (fds->revents != 0)
{
nxsem_post(fds->sem);
}
}
leave_critical_section(flags);
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxterm_read
*
* Description:
* The optional NxTerm read method
*
****************************************************************************/
ssize_t nxterm_read(FAR struct file *filep, FAR char *buffer, size_t len)
{
FAR struct nxterm_state_s *priv;
ssize_t nread;
char ch;
int ret;
/* Recover our private state structure */
DEBUGASSERT(filep && filep->f_priv);
priv = (FAR struct nxterm_state_s *)filep->f_priv;
/* Get exclusive access to the driver structure */
ret = nxterm_semwait(priv);
if (ret < 0)
{
gerr("ERROR: nxterm_semwait failed\n");
return ret;
}
/* Loop until something is read */
for (nread = 0; nread < len; )
{
/* Get the next byte from the buffer */
if (priv->head == priv->tail)
{
/* The circular buffer is empty. Did we read anything? */
if (nread > 0)
{
/* Yes.. break out to return what we have. */
break;
}
/* If the driver was opened with O_NONBLOCK option, then
* don't wait. Just return EGAIN.
*/
if (filep->f_oflags & O_NONBLOCK)
{
nread = -EAGAIN;
break;
}
/* Otherwise, wait for something to be written to the circular
* buffer. Increment the number of waiters so that the
* nxterm_write() will not that it needs to post the semaphore
* to wake us up.
*/
sched_lock();
priv->nwaiters++;
nxterm_sempost(priv);
/* We may now be pre-empted! But that should be okay because we
* have already incremented nwaiters. Pre-emption is disabled
* but will be re-enabled while we are waiting.
*/
ret = nxsem_wait(&priv->waitsem);
/* Pre-emption will be disabled when we return. So the
* decrementing nwaiters here is safe.
*/
priv->nwaiters--;
sched_unlock();
/* Did we successfully get the waitsem? */
if (ret >= 0)
{
/* Yes... then retake the mutual exclusion semaphore */
ret = nxterm_semwait(priv);
}
/* Was the semaphore wait successful? Did we successful re-take the
* mutual exclusion semaphore?
*/
if (ret < 0)
{
/* No.. One of the two nxterm_semwait's failed. */
gerr("ERROR: nxterm_semwait failed\n");
/* Were we awakened by a signal? Did we read anything before
* we received the signal?
*/
if (ret != -EINTR || nread >= 0)
{
/* Yes.. return the error. */
nread = ret;
}
/* Break out to return what we have. Note, we can't exactly
* "break" out because whichever error occurred, we do not hold
* the exclusion semaphore.
*/
goto errout_without_sem;
}
}
else
{
/* The circular buffer is not empty, get the next byte from the
* tail index.
*/
ch = priv->rxbuffer[priv->tail];
/* Increment the tail index and re-enable interrupts */
if (++priv->tail >= CONFIG_NXTERM_KBDBUFSIZE)
{
priv->tail = 0;
}
/* Add the character to the user buffer */
buffer[nread] = ch;
nread++;
}
}
/* Relinquish the mutual exclusion semaphore */
nxterm_sempost(priv);
/* Notify all poll/select waiters that they can write to the FIFO */
errout_without_sem:
if (nread > 0)
{
nxterm_pollnotify(priv, POLLOUT);
}
/* Return the number of characters actually read */
return nread;
}
/****************************************************************************
* Name: nxterm_poll
****************************************************************************/
int nxterm_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup)
{
FAR struct inode *inode = filep->f_inode;
FAR struct nxterm_state_s *priv;
pollevent_t eventset;
int ret;
int i;
/* Some sanity checking */
DEBUGASSERT(inode && inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
ret = nxterm_semwait(priv);
if (ret < 0)
{
gerr("ERROR: nxterm_semwait failed\n");
return ret;
}
/* Are we setting up the poll? Or tearing it down? */
if (setup)
{
/* This is a request to set up the poll. Find an available
* slot for the poll structure reference
*/
for (i = 0; i < CONFIG_NXTERM_NPOLLWAITERS; i++)
{
/* Find an available slot */
if (!priv->fds[i])
{
/* Bind the poll structure and this slot */
priv->fds[i] = fds;
fds->priv = &priv->fds[i];
break;
}
}
if (i >= CONFIG_NXTERM_NPOLLWAITERS)
{
gerr("ERROR: Too many poll waiters\n");
fds->priv = NULL;
ret = -EBUSY;
goto errout;
}
/* Should immediately notify on any of the requested events?
* This driver is always available for transmission.
*/
eventset = POLLOUT;
/* Check if the receive buffer is empty */
if (priv->head != priv->tail)
{
eventset |= POLLIN;
}
if (eventset)
{
nxterm_pollnotify(priv, eventset);
}
}
else if (fds->priv)
{
/* This is a request to tear down the poll. */
struct pollfd **slot = (struct pollfd **)fds->priv;
#ifdef CONFIG_DEBUG_GRAPHICS
if (!slot)
{
gerr("ERROR: No slot\n");
ret = -EIO;
goto errout;
}
#endif
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
errout:
nxterm_sempost(priv);
return ret;
}
/****************************************************************************
* Name: nxterm_kbdin
*
* Description:
* This function should be driven by the window kbdin callback function
* (see nx.h). When the NxTerm is the top window and keyboard input is
* received on the top window, that window callback should be directed to
* this function. This function will buffer the keyboard data and makE
* it available to the NxTerm as stdin.
*
* If CONFIG_NXTERM_NXKBDIN is not selected, then the NxTerm will
* receive its input from stdin (/dev/console). This works great but
* cannot be shared between different windows. Chaos will ensue if you
* try to support multiple NxTerm windows without CONFIG_NXTERM_NXKBDIN
*
* Input Parameters:
* handle - A handle previously returned by nx_register, nxtk_register, or
* nxtool_register.
* buffer - The array of characters
* buflen - The number of characters that are available in buffer[]
*
* Returned Value:
* None
*
****************************************************************************/
void nxterm_kbdin(NXTERM handle, FAR const uint8_t *buffer, uint8_t buflen)
{
FAR struct nxterm_state_s *priv;
ssize_t nwritten;
int nexthead;
char ch;
int ret;
ginfo("buflen=%" PRId8 "\n", buflen);
DEBUGASSERT(handle);
/* Get the reference to the driver structure from the handle */
priv = (FAR struct nxterm_state_s *)handle;
/* Get exclusive access to the driver structure */
ret = nxterm_semwait(priv);
if (ret < 0)
{
gerr("ERROR: nxterm_semwait failed\n");
return;
}
/* Loop until all of the bytes have been written. This function may be
* called from an interrupt handler! Semaphores cannot be used!
*
* The write logic only needs to modify the head index. Therefore,
* there is a difference in the way that head and tail are protected:
* tail is protected with a semaphore; tail is protected by disabling
* interrupts.
*/
for (nwritten = 0; nwritten < buflen; nwritten++)
{
/* Add the next character */
ch = buffer[nwritten];
/* Calculate the write index AFTER the next byte is add to the ring
* buffer
*/
nexthead = priv->head + 1;
if (nexthead >= CONFIG_NXTERM_KBDBUFSIZE)
{
nexthead = 0;
}
/* Would the next write overflow the circular buffer? */
if (nexthead == priv->tail)
{
/* Yes... Return an indication that nothing was saved in
* the buffer.
*/
gerr("ERROR: Keyboard data overrun\n");
break;
}
/* No... copy the byte */
priv->rxbuffer[priv->head] = ch;
priv->head = nexthead;
}
/* Was anything written? */
if (nwritten > 0)
{
int i;
/* Are there threads waiting for read data? */
sched_lock();
/* Notify all poll/select waiters that they can read from the FIFO */
nxterm_pollnotify(priv, POLLIN);
for (i = 0; i < priv->nwaiters; i++)
{
/* Yes.. Notify all of the waiting readers that more data is
* available
*/
nxsem_post(&priv->waitsem);
}
sched_unlock();
}
nxterm_sempost(priv);
}
#endif /* CONFIG_NXTERM_NXKBDIN */
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