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px4-firmware/nuttx/graphics/nxconsole/nxcon_kbdin.c

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/****************************************************************************
* nuttx/graphics/nxconsole/nxcon_kbdin.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <fcntl.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include "nxcon_internal.h"
#ifdef CONFIG_NXCONSOLE_NXKBDIN
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nxcon_pollnotify
****************************************************************************/
#ifndef CONFIG_DISABLE_POLL
static void nxcon_pollnotify(FAR struct nxcon_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_NXCONSOLE_NPOLLWAITERS; i++)
{
flags = irqsave();
fds = priv->fds[i];
if (fds)
{
fds->revents |= (fds->events & eventset);
if (fds->revents != 0)
{
sem_post(fds->sem);
}
}
irqrestore(flags);
}
}
#else
# define nxcon_pollnotify(priv,event)
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxcon_read
*
* Description:
* The optional NxConsole read method
*
****************************************************************************/
ssize_t nxcon_read(FAR struct file *filep, FAR char *buffer, size_t len)
{
FAR struct nxcon_state_s *priv;
ssize_t nread;
char ch;
int ret;
/* Recover our private state structure */
DEBUGASSERT(filep && filep->f_priv);
priv = (FAR struct nxcon_state_s *)filep->f_priv;
/* Get exclusive access to the driver structure */
ret = nxcon_semwait(priv);
if (ret < 0)
{
gdbg("ERROR: nxcon_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 nxcon_write()
* will not that it needs to post the semaphore to wake us up.
*/
sched_lock();
priv->nwaiters++;
nxcon_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 = sem_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 = nxcon_semwait(priv);
}
/* Was the semaphore wait successful? Did we successful re-take the
* mutual exclusion semaphore?
*/
if (ret < 0)
{
/* No.. One of the two sem_wait's failed. */
int errval = errno;
gdbg("ERROR: nxcon_semwait failed\n");
/* Were we awakened by a signal? Did we read anything before
* we received the signal?
*/
if (errval != EINTR || nread >= 0)
{
/* Yes.. return the error. */
nread = -errval;
}
/* 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_NXCONSOLE_KBDBUFSIZE)
{
priv->tail = 0;
}
/* Add the character to the user buffer */
buffer[nread] = ch;
nread++;
}
}
/* Relinquish the mutual exclusion semaphore */
nxcon_sempost(priv);
/* Notify all poll/select waiters that they can write to the FIFO */
errout_without_sem:
#ifndef CONFIG_DISABLE_POLL
if (nread > 0)
{
nxcon_pollnotify(priv, POLLOUT);
}
#endif
/* Return the number of characters actually read */
return nread;
}
/****************************************************************************
* Name: nxcon_poll
****************************************************************************/
#ifndef CONFIG_DISABLE_POLL
int nxcon_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup)
{
FAR struct inode *inode = filep->f_inode;
FAR struct nxcon_state_s *priv;
pollevent_t eventset;
int ndx;
int ret;
int i;
/* Some sanity checking */
DEBUGASSERT(inode && inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
ret = nxcon_semwait(priv);
if (ret < 0)
{
gdbg("ERROR: nxcon_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_NXCONSOLE_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_NXCONSOLE_NPOLLWAITERS)
{
gdbg("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)
{
nxcon_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
if (!slot)
{
gdbg("ERROR: No slot\n");
ret = -EIO;
goto errout;
}
#endif
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
errout:
nxcon_sempost(priv);
return ret;
}
#endif
/****************************************************************************
* Name: nxcon_kbdin
*
* Description:
* This function should be driven by the window kbdin callback function
* (see nx.h). When the NxConsole 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 may
* it available to the NxConsole as stdin.
*
* If CONFIG_NXCONSOLE_NXKBDIN is not selected, then the NxConsole 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 NxConsole windows without CONFIG_NXCONSOLE_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 nxcon_kbdin(NXCONSOLE handle, FAR const uint8_t *buffer, uint8_t buflen)
{
FAR struct nxcon_state_s *priv;
ssize_t nwritten;
int nexthead;
char ch;
int ret;
gvdbg("buflen=%d\n");
DEBUGASSERT(handle);
/* Get the reference to the driver structure from the handle */
priv = (FAR struct nxcon_state_s *)handle;
/* Get exclusive access to the driver structure */
ret = nxcon_semwait(priv);
if (ret < 0)
{
gdbg("ERROR: nxcon_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_NXCONSOLE_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. */
gdbg("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();
for (i = 0; i < priv->nwaiters; i++)
{
/* Yes.. Notify all of the waiting readers that more data is available */
sem_post(&priv->waitsem);
}
/* Notify all poll/select waiters that they can write to the FIFO */
#ifndef CONFIG_DISABLE_POLL
nxcon_pollnotify(priv, POLLIN);
#endif
sched_unlock();
}
nxcon_sempost(priv);
}
#endif /* CONFIG_NXCONSOLE_NXKBDIN */
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