static void uart_putxmitchar(FAR uart_dev_t *dev, int ch)
{
irqstate_t flags;
int nexthead;
/* Increment to see what the next head pointer will be. We need to use the "next"
* head pointer to determine when the circular buffer would overrun
*/
nexthead = dev->xmit.head + 1;
if (nexthead >= dev->xmit.size)
{
nexthead = 0;
}
/* Loop until we are able to add the character to the TX buffer */
for (;;)
{
if (nexthead != dev->xmit.tail)
{
dev->xmit.buffer[dev->xmit.head] = ch;
dev->xmit.head = nexthead;
return;
}
else
{
/* Inform the interrupt level logic that we are waiting.
* This and the following steps must be atomic.
*/
flags = irqsave();
dev->xmitwaiting = true;
/* Wait for some characters to be sent from the buffer
* with the TX interrupt enabled. When the TX interrupt
* is enabled, uart_xmitchars should execute and remove
* some of the data from the TX buffer.
*/
uart_enabletxint(dev);
uart_takesem(&dev->xmitsem);
uart_disabletxint(dev);
irqrestore(flags);
}
}
}
static ssize_t uart_write(FAR struct file *filep, FAR const char *buffer, size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR uart_dev_t *dev = inode->i_private;
ssize_t ret = buflen;
/* We may receive console writes through this path from
* interrupt handlers and from debug output in the IDLE task!
* In these cases, we will need to do things a little
* differently.
*/
if (up_interrupt_context() || getpid() == 0)
{
if (dev->isconsole)
{
irqstate_t flags = irqsave();
ret = uart_irqwrite(dev, buffer, buflen);
irqrestore(flags);
return ret;
}
else
{
return ERROR;
}
}
/* Only one user can be accessing dev->xmit.head at once */
uart_takesem(&dev->xmit.sem);
/* Loop while we still have data to copy to the transmit buffer.
* we add data to the head of the buffer; uart_xmitchars takes the
* data from the end of the buffer.
*/
uart_disabletxint(dev);
for (; buflen; buflen--)
{
int ch = *buffer++;
/* Put the character into the transmit buffer */
uart_putxmitchar(dev, ch);
/* If this is the console, then we should replace LF with LF-CR */
if (dev->isconsole && ch == '\n')
{
uart_putxmitchar(dev, '\r');
}
}
if (dev->xmit.head != dev->xmit.tail)
{
uart_enabletxint(dev);
}
uart_givesem(&dev->xmit.sem);
return ret;
}
static ssize_t uart_write(FAR struct file *filep, FAR const char *buffer, size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR uart_dev_t *dev = inode->i_private;
ssize_t nread = buflen;
int ret;
/* We may receive console writes through this path from interrupt handlers and
* from debug output in the IDLE task! In these cases, we will need to do things
* a little differently.
*/
if (up_interrupt_context() || getpid() == 0)
{
/* up_putc() will be used to generate the output in a busy-wait loop.
* up_putc() is only available for the console device.
*/
if (dev->isconsole)
{
irqstate_t flags = irqsave();
ret = uart_irqwrite(dev, buffer, buflen);
irqrestore(flags);
return ret;
}
else
{
return -EPERM;
}
}
/* Only one user can access dev->xmit.head at a time */
ret = (ssize_t)uart_takesem(&dev->xmit.sem, true);
if (ret < 0)
{
/* A signal received while waiting for access to the xmit.head will
* abort the transfer. After the transfer has started, we are committed
* and signals will be ignored.
*/
return ret;
}
/* Loop while we still have data to copy to the transmit buffer.
* we add data to the head of the buffer; uart_xmitchars takes the
* data from the end of the buffer.
*/
uart_disabletxint(dev);
for (; buflen; buflen--)
{
int ch = *buffer++;
/* If the ONLCR flag is set, we should translate \n to \r\n */
ret = OK;
if ((ch == '\n') && (dev->termios_s.c_oflag && ONLCR))
{
ret = uart_putxmitchar(dev, '\r');
}
/* Put the character into the transmit buffer */
if (ret == OK)
{
ret = uart_putxmitchar(dev, ch);
}
/* Were we awakened by a signal? That should be the only condition that
* uart_putxmitchar() should return an error.
*/
if (ret < 0)
{
/* POSIX requires that we return -1 and errno set if no data was
* transferred. Otherwise, we return the number of bytes in the
* interrupted transfer.
*/
if (buflen < nread)
{
/* Some data was transferred. Return the number of bytes that were
* successfully transferred.
*/
nread -= buflen;
}
else
{
/* No data was transferred. Return -EINTR. The VFS layer will
* set the errno value appropriately).
*/
nread = -EINTR;
}
break;
}
}
if (dev->xmit.head != dev->xmit.tail)
{
uart_enabletxint(dev);
}
uart_givesem(&dev->xmit.sem);
return nread;
}
static int uart_putxmitchar(FAR uart_dev_t *dev, int ch)
{
irqstate_t flags;
int nexthead;
int ret;
/* Increment to see what the next head pointer will be. We need to use the "next"
* head pointer to determine when the circular buffer would overrun
*/
nexthead = dev->xmit.head + 1;
if (nexthead >= dev->xmit.size)
{
nexthead = 0;
}
/* Loop until we are able to add the character to the TX buffer */
for (;;)
{
if (nexthead != dev->xmit.tail)
{
dev->xmit.buffer[dev->xmit.head] = ch;
dev->xmit.head = nexthead;
return OK;
}
else
{
/* Inform the interrupt level logic that we are waiting. This and
* the following steps must be atomic.
*/
flags = irqsave();
dev->xmitwaiting = true;
/* Wait for some characters to be sent from the buffer with the TX
* interrupt enabled. When the TX interrupt is enabled, uart_xmitchars
* should execute and remove some of the data from the TX buffer.
*/
uart_enabletxint(dev);
ret = uart_takesem(&dev->xmitsem, true);
uart_disabletxint(dev);
irqrestore(flags);
/* Check if we were awakened by signal. */
if (ret < 0)
{
/* A signal received while waiting for the xmit buffer to become
* non-full will abort the transfer.
*/
return -EINTR;
}
}
}
/* We won't get here */
return OK;
}
static ssize_t uart_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR uart_dev_t *dev = inode->i_private;
ssize_t nwritten = buflen;
bool oktoblock;
int ret;
char ch;
/* We may receive console writes through this path from interrupt handlers and
* from debug output in the IDLE task! In these cases, we will need to do things
* a little differently.
*/
if (up_interrupt_context() || getpid() == 0)
{
#ifdef CONFIG_SERIAL_REMOVABLE
/* If the removable device is no longer connected, refuse to write to
* the device.
*/
if (dev->disconnected)
{
return -ENOTCONN;
}
#endif
/* up_putc() will be used to generate the output in a busy-wait loop.
* up_putc() is only available for the console device.
*/
if (dev->isconsole)
{
irqstate_t flags = irqsave();
ret = uart_irqwrite(dev, buffer, buflen);
irqrestore(flags);
return ret;
}
else
{
return -EPERM;
}
}
/* Only one user can access dev->xmit.head at a time */
ret = (ssize_t)uart_takesem(&dev->xmit.sem, true);
if (ret < 0)
{
/* A signal received while waiting for access to the xmit.head will
* abort the transfer. After the transfer has started, we are committed
* and signals will be ignored.
*/
return ret;
}
#ifdef CONFIG_SERIAL_REMOVABLE
/* If the removable device is no longer connected, refuse to write to the
* device. This check occurs after taking the xmit.sem because the
* disconnection event might have occurred while we were waiting for
* access to the transmit buffers.
*/
if (dev->disconnected)
{
uart_givesem(&dev->xmit.sem);
return -ENOTCONN;
}
#endif
/* Can the following loop block, waiting for space in the TX
* buffer?
*/
oktoblock = ((filep->f_oflags & O_NONBLOCK) == 0);
/* Loop while we still have data to copy to the transmit buffer.
* we add data to the head of the buffer; uart_xmitchars takes the
* data from the end of the buffer.
*/
uart_disabletxint(dev);
for (; buflen; buflen--)
{
ch = *buffer++;
ret = OK;
#ifdef CONFIG_SERIAL_TERMIOS
/* Do output post-processing */
if (dev->tc_oflag & OPOST)
{
/* Mapping CR to NL? */
if ((ch == '\r') && (dev->tc_oflag & OCRNL))
{
ch = '\n';
}
/* Are we interested in newline processing? */
if ((ch == '\n') && (dev->tc_oflag & (ONLCR | ONLRET)))
{
ret = uart_putxmitchar(dev, '\r', oktoblock);
if (ret < 0)
{
break;
}
}
/* Specifically not handled:
*
* OXTABS - primarily a full-screen terminal optimisation
* ONOEOT - Unix interoperability hack
* OLCUC - Not specified by Posix
* ONOCR - low-speed interactive optimisation
*/
}
#else /* !CONFIG_SERIAL_TERMIOS */
/* If this is the console, convert \n -> \r\n */
if (dev->isconsole && ch == '\n')
{
ret = uart_putxmitchar(dev, '\r', oktoblock);
}
#endif
/* Put the character into the transmit buffer */
if (ret == OK)
{
ret = uart_putxmitchar(dev, ch, oktoblock);
}
/* uart_putxmitchar() might return an error under one of two
* conditions: (1) The wait for buffer space might have been
* interrupted by a signal (ret should be -EINTR), (2) if
* CONFIG_SERIAL_REMOVABLE is defined, then uart_putxmitchar()
* might also return if the serial device was disconnected
* (with -ENOTCONN), or (3) if O_NONBLOCK is specified, then
* then uart_putxmitchar() might return -EAGAIN if the output
* TX buffer is full.
*/
if (ret < 0)
{
/* POSIX requires that we return -1 and errno set if no data was
* transferred. Otherwise, we return the number of bytes in the
* interrupted transfer.
*/
if (buflen < nwritten)
{
/* Some data was transferred. Return the number of bytes that
* were successfully transferred.
*/
nwritten -= buflen;
}
else
{
/* No data was transferred. Return the negated errno value.
* The VFS layer will set the errno value appropriately).
*/
nwritten = ret;
}
break;
}
}
if (dev->xmit.head != dev->xmit.tail)
{
uart_enabletxint(dev);
}
uart_givesem(&dev->xmit.sem);
return nwritten;
}
static int uart_putxmitchar(FAR uart_dev_t *dev, int ch, bool oktoblock)
{
irqstate_t flags;
int nexthead;
int ret;
/* Increment to see what the next head pointer will be. We need to use the "next"
* head pointer to determine when the circular buffer would overrun
*/
nexthead = dev->xmit.head + 1;
if (nexthead >= dev->xmit.size)
{
nexthead = 0;
}
/* Loop until we are able to add the character to the TX buffer */
for (;;)
{
if (nexthead != dev->xmit.tail)
{
dev->xmit.buffer[dev->xmit.head] = ch;
dev->xmit.head = nexthead;
return OK;
}
/* The buffer is full and no data is available now. Should be block,
* waiting for the hardware to remove some data from the TX
* buffer?
*/
else if (oktoblock)
{
/* Inform the interrupt level logic that we are waiting. This and
* the following steps must be atomic.
*/
flags = irqsave();
#ifdef CONFIG_SERIAL_REMOVABLE
/* Check if the removable device is no longer connected while we
* have interrupts off. We do not want the transition to occur
* as a race condition before we begin the wait.
*/
if (dev->disconnected)
{
ret = -ENOTCONN;
}
else
#endif
{
/* Wait for some characters to be sent from the buffer with
* the TX interrupt enabled. When the TX interrupt is
* enabled, uart_xmitchars should execute and remove some
* of the data from the TX buffer.
*/
dev->xmitwaiting = true;
uart_enabletxint(dev);
ret = uart_takesem(&dev->xmitsem, true);
uart_disabletxint(dev);
}
irqrestore(flags);
#ifdef CONFIG_SERIAL_REMOVABLE
/* Check if the removable device was disconnected while we were
* waiting.
*/
if (dev->disconnected)
{
return -ENOTCONN;
}
#endif
/* Check if we were awakened by signal. */
if (ret < 0)
{
/* A signal received while waiting for the xmit buffer to become
* non-full will abort the transfer.
*/
return -EINTR;
}
}
/* The caller has request that we not block for data. So return the
* EAGAIN error to signal this situation.
*/
else
{
return -EAGAIN;
}
}
/* We won't get here. Some compilers may complain that this code is
* unreachable.
*/
return OK;
}
static ssize_t uart_write(FAR struct file *filep, FAR const char *buffer, size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR uart_dev_t *dev = inode->i_private;
ssize_t nread = buflen;
int ret;
char ch;
/* We may receive console writes through this path from interrupt handlers and
* from debug output in the IDLE task! In these cases, we will need to do things
* a little differently.
*/
if (up_interrupt_context() || getpid() == 0)
{
/* up_putc() will be used to generate the output in a busy-wait loop.
* up_putc() is only available for the console device.
*/
if (dev->isconsole)
{
irqstate_t flags = irqsave();
ret = uart_irqwrite(dev, buffer, buflen);
irqrestore(flags);
return ret;
}
else
{
return -EPERM;
}
}
/* Only one user can access dev->xmit.head at a time */
ret = (ssize_t)uart_takesem(&dev->xmit.sem, true);
if (ret < 0)
{
/* A signal received while waiting for access to the xmit.head will
* abort the transfer.
*/
return ret;
}
/* Loop while we still have data to copy to the transmit buffer.
* we add data to the head of the buffer; uart_xmitchars takes the
* data from the end of the buffer.
*/
uart_disabletxint(dev);
for (; buflen; buflen--)
{
ch = *buffer++;
/* Do output post-processing */
#ifdef CONFIG_SERIAL_TERMIOS
if (dev->tc_oflag & OPOST)
{
/* Mapping CR to NL? */
if ((ch == '\r') && (dev->tc_oflag & OCRNL))
{
ch = '\n';
}
/* Are we interested in newline processing? */
if ((ch == '\n') && (dev->tc_oflag & (ONLCR | ONLRET)))
{
ret = uart_putxmitchar(dev, '\r');
if (ret != OK)
{
break;
}
}
/* Specifically not handled:
*
* OXTABS - primarily a full-screen terminal optimisation
* ONOEOT - Unix interoperability hack
* OLCUC - Not specified by Posix
* ONOCR - low-speed interactive optimisation
*/
}
#else /* !CONFIG_SERIAL_TERMIOS */
/* If this is the console, convert \n -> \r\n */
if (dev->isconsole && ch == '\n')
{
ret = uart_putxmitchar(dev, '\r');
}
#endif
/* Put the character into the transmit buffer */
ret = uart_putxmitchar(dev, ch);
if (ret != OK)
{
break;
}
}
if (dev->xmit.head != dev->xmit.tail)
{
uart_enabletxint(dev);
}
uart_givesem(&dev->xmit.sem);
/* Were we interrupted by a signal? That should be the only condition that
* uart_putxmitchar() should return an error.
*/
if (ret < 0)
{
/* POSIX requires that we return -1 and errno set if no data was
* transferred. Otherwise, we return the number of bytes in the
* interrupted transfer.
*/
if (buflen < nread)
{
/* Some data was transferred. Return the number of bytes that were
* successfully transferred.
*/
nread -= buflen;
}
else
{
/* No data was transferred. Return -EINTR. The VFS layer will
* set the errno value appropriately).
*/
nread = -EINTR;
}
}
return nread;
}
