/************************************************************************************ * drivers/serial/serial.c * * Copyright (C) 2007-2009, 2011-2013, 2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /************************************************************************************ * Pre-processor Definitions ************************************************************************************/ /* The architecture must provide up_putc for this driver */ #ifndef CONFIG_ARCH_LOWPUTC # error "Architecture must provide up_putc() for this driver" #endif #define uart_putc(ch) up_putc(ch) #define HALF_SECOND_MSEC 500 #define HALF_SECOND_USEC 500000L /************************************************************************************ * Private Types ************************************************************************************/ /************************************************************************************ * Private Function Prototypes ************************************************************************************/ static int uart_open(FAR struct file *filep); static int uart_close(FAR struct file *filep); static ssize_t uart_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t uart_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg); #ifndef CONFIG_DISABLE_POLL static int uart_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup); #endif /************************************************************************************ * Private Data ************************************************************************************/ static const struct file_operations g_serialops = { uart_open, /* open */ uart_close, /* close */ uart_read, /* read */ uart_write, /* write */ 0, /* seek */ uart_ioctl /* ioctl */ #ifndef CONFIG_DISABLE_POLL , uart_poll /* poll */ #endif #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL /* unlink */ #endif }; /************************************************************************************ * Private Functions ************************************************************************************/ /************************************************************************************ * Name: uart_takesem ************************************************************************************/ static int uart_takesem(FAR sem_t *sem, bool errout) { /* Loop, ignoring interrupts, until we have successfully acquired the semaphore */ while (sem_wait(sem) != OK) { /* The only case that an error should occur here is if the wait was awakened * by a signal. */ ASSERT(get_errno() == EINTR); /* When the signal is received, should we errout? Or should we just continue * waiting until we have the semaphore? */ if (errout) { return -EINTR; } } return OK; } /************************************************************************************ * Name: uart_givesem ************************************************************************************/ #define uart_givesem(sem) (void)sem_post(sem) /**************************************************************************** * Name: uart_pollnotify ****************************************************************************/ #ifndef CONFIG_DISABLE_POLL static void uart_pollnotify(FAR uart_dev_t *dev, pollevent_t eventset) { int i; for (i = 0; i < CONFIG_SERIAL_NPOLLWAITERS; i++) { struct pollfd *fds = dev->fds[i]; if (fds) { #ifdef CONFIG_SERIAL_REMOVABLE fds->revents |= ((fds->events | (POLLERR | POLLHUP)) & eventset); #else fds->revents |= (fds->events & eventset); #endif if (fds->revents != 0) { finfo("Report events: %02x\n", fds->revents); sem_post(fds->sem); } } } } #else # define uart_pollnotify(dev,event) #endif /************************************************************************************ * Name: uart_putxmitchar ************************************************************************************/ 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 (; ; ) { /* Check if the TX buffer is full */ if (nexthead != dev->xmit.tail) { /* No.. not full. Add the character to the TX buffer and return. */ dev->xmit.buffer[dev->xmit.head] = ch; dev->xmit.head = nexthead; return OK; } /* The TX buffer is full. Should be block, waiting for the hardware * to remove some data from the TX buffer? */ else if (oktoblock) { /* The following steps must be atomic with respect to serial * interrupt handling. */ flags = enter_critical_section(); /* Check again... In certain race conditions an interrupt may * have occurred between the test at the top of the loop and * entering the critical section and the TX buffer may no longer * be full. * * NOTE: On certain devices, such as USB CDC/ACM, the entire TX * buffer may have been emptied in this race condition. In that * case, the logic would hang below waiting for space in the TX * buffer without this test. */ if (nexthead != dev->xmit.tail) { ret = OK; } #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. */ else if (dev->disconnected) { ret = -ENOTCONN; } #endif else { /* Inform the interrupt level logic that we are waiting. */ 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. * * NOTE that interrupts will be re-enabled while we wait for * the semaphore. */ #ifdef CONFIG_SERIAL_DMA uart_dmatxavail(dev); #endif uart_enabletxint(dev); ret = uart_takesem(&dev->xmitsem, true); uart_disabletxint(dev); } leave_critical_section(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; } /************************************************************************************ * Name: uart_irqwrite ************************************************************************************/ static inline ssize_t uart_irqwrite(FAR uart_dev_t *dev, FAR const char *buffer, size_t buflen) { ssize_t ret = buflen; /* Force each character through the low level interface */ for (; buflen; buflen--) { int ch = *buffer++; /* If this is the console, then we should replace LF with CR-LF */ if (ch == '\n') { uart_putc('\r'); } /* Output the character, using the low-level direct UART interfaces */ uart_putc(ch); } return ret; } /************************************************************************************ * Name: uart_write ************************************************************************************/ 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 = enter_critical_section(); ret = uart_irqwrite(dev, buffer, buflen); leave_critical_section(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) != 0) { /* Mapping CR to NL? */ if ((ch == '\r') && (dev->tc_oflag & OCRNL) != 0) { ch = '\n'; } /* Are we interested in newline processing? */ if ((ch == '\n') && (dev->tc_oflag & (ONLCR | ONLRET)) != 0) { ret = uart_putxmitchar(dev, '\r', oktoblock); if (ret < 0) { nwritten = ret; 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 < (size_t)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) { #ifdef CONFIG_SERIAL_DMA uart_dmatxavail(dev); #endif uart_enabletxint(dev); } uart_givesem(&dev->xmit.sem); return nwritten; } /************************************************************************************ * Name: uart_read ************************************************************************************/ static ssize_t uart_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR uart_dev_t *dev = inode->i_private; FAR struct uart_buffer_s *rxbuf = &dev->recv; #ifdef CONFIG_SERIAL_IFLOWCONTROL_WATERMARKS unsigned int nbuffered; unsigned int watermark; #endif irqstate_t flags; ssize_t recvd = 0; int16_t tail; char ch; int ret; /* Only one user can access rxbuf->tail at a time */ ret = uart_takesem(&rxbuf->sem, true); if (ret < 0) { /* A signal received while waiting for access to the recv.tail will avort * 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 receive buffer. * we add data to the head of the buffer; uart_xmitchars takes the * data from the end of the buffer. */ while ((size_t)recvd < buflen) { #ifdef CONFIG_SERIAL_REMOVABLE /* If the removable device is no longer connected, refuse to read any * further from the device. */ if (dev->disconnected) { if (recvd == 0) { recvd = -ENOTCONN; } break; } #endif /* Check if there is more data to return in the circular buffer. * NOTE: Rx interrupt handling logic may asynchronously increment * the head index but must not modify the tail index. The tail * index is only modified in this function. Therefore, no * special handshaking is required here. * * The head and tail pointers are 16-bit values. The only time that * the following could be unsafe is if the CPU made two non-atomic * 8-bit accesses to obtain the 16-bit head index. */ tail = rxbuf->tail; if (rxbuf->head != tail) { /* Take the next character from the tail of the buffer */ ch = rxbuf->buffer[tail]; /* Increment the tail index. Most operations are done using the * local variable 'tail' so that the final rxbuf->tail update * is atomic. */ if (++tail >= rxbuf->size) { tail = 0; } rxbuf->tail = tail; #ifdef CONFIG_SERIAL_TERMIOS /* Do input processing if any is enabled */ if (dev->tc_iflag & (INLCR | IGNCR | ICRNL)) { /* \n -> \r or \r -> \n translation? */ if ((ch == '\n') && (dev->tc_iflag & INLCR)) { ch = '\r'; } else if ((ch == '\r') && (dev->tc_iflag & ICRNL)) { ch = '\n'; } /* Discarding \r ? */ if ((ch == '\r') & (dev->tc_iflag & IGNCR)) { continue; } } /* Specifically not handled: * * All of the local modes; echo, line editing, etc. * Anything to do with break or parity errors. * ISTRIP - we should be 8-bit clean. * IUCLC - Not Posix * IXON/OXOFF - no xon/xoff flow control. */ #endif /* Store the received character */ *buffer++ = ch; recvd++; } #ifdef CONFIG_DEV_SERIAL_FULLBLOCKS /* No... then we would have to wait to get receive more data. * If the user has specified the O_NONBLOCK option, then just * return what we have. */ else if ((filep->f_oflags & O_NONBLOCK) != 0) { /* If nothing was transferred, then return the -EAGAIN * error (not zero which means end of file). */ if (recvd < 1) { recvd = -EAGAIN; } break; } #else /* No... the circular buffer is empty. Have we returned anything * to the caller? */ else if (recvd > 0) { /* Yes.. break out of the loop and return the number of bytes * received up to the wait condition. */ break; } /* No... then we would have to wait to get receive some data. * If the user has specified the O_NONBLOCK option, then do not * wait. */ else if ((filep->f_oflags & O_NONBLOCK) != 0) { /* Break out of the loop returning -EAGAIN */ recvd = -EAGAIN; break; } #endif /* Otherwise we are going to have to wait for data to arrive */ else { /* Disable Rx interrupts and test again... */ uart_disablerxint(dev); /* If the Rx ring buffer still empty? Bytes may have been addded * between the last time that we checked and when we disabled Rx * interrupts. */ if (rxbuf->head == rxbuf->tail) { /* Yes.. the buffer is still empty. Wait for some characters * to be received into the buffer with the RX interrupt re- * enabled. All interrupts are disabled briefly to assure * that the following operations are atomic. */ flags = enter_critical_section(); #ifdef CONFIG_SERIAL_DMA /* If RX buffer is empty move tail and head to zero position */ if (rxbuf->head == rxbuf->tail) { rxbuf->head = rxbuf->tail = 0; } /* Notify DMA that there is free space in the RX buffer */ uart_dmarxfree(dev); #endif uart_enablerxint(dev); #ifdef CONFIG_SERIAL_REMOVABLE /* Check again if the removable device is still 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 { /* Now wait with the Rx interrupt re-enabled. NuttX will * automatically re-enable global interrupts when this * thread goes to sleep. */ dev->recvwaiting = true; ret = uart_takesem(&dev->recvsem, true); } leave_critical_section(flags); /* Was a signal received while waiting for data to be * received? Was a removable device disconnected while * we were waiting? */ #ifdef CONFIG_SERIAL_REMOVABLE if (ret < 0 || dev->disconnected) #else if (ret < 0) #endif { /* POSIX requires that we return after a signal is received. * If some bytes were read, we need to return the number of bytes * read; if no bytes were read, we need to return -1 with the * errno set correctly. */ if (recvd == 0) { /* No bytes were read, return -EINTR (the VFS layer will * set the errno value appropriately. */ #ifdef CONFIG_SERIAL_REMOVABLE recvd = dev->disconnected ? -ENOTCONN : -EINTR; #else recvd = -EINTR; #endif } break; } } else { /* No... the ring buffer is no longer empty. Just re-enable Rx * interrupts and accept the new data on the next time through * the loop. */ uart_enablerxint(dev); } } } #ifdef CONFIG_SERIAL_DMA flags = enter_critical_section(); /* If RX buffer is empty move tail and head to zero position */ if (rxbuf->head == rxbuf->tail) { rxbuf->head = rxbuf->tail = 0; } leave_critical_section(flags); /* Notify DMA that there is free space in the RX buffer */ uart_dmarxfree(dev); /* RX interrupt could be disabled by RX buffer overflow. Enable it now. */ uart_enablerxint(dev); #endif #ifdef CONFIG_SERIAL_IFLOWCONTROL #ifdef CONFIG_SERIAL_IFLOWCONTROL_WATERMARKS /* How many bytes are now buffered */ rxbuf = &dev->recv; if (rxbuf->head >= rxbuf->tail) { nbuffered = rxbuf->head - rxbuf->tail; } else { nbuffered = rxbuf->size - rxbuf->tail + rxbuf->head; } /* Is the level now below the watermark level that we need to report? */ watermark = (CONFIG_SERIAL_IFLOWCONTROL_LOWER_WATERMARK * rxbuf->size) / 100; if (nbuffered <= watermark) { /* Let the lower level driver know that the watermark level has been * crossed. It will probably deactivate RX flow control. */ (void)uart_rxflowcontrol(dev, nbuffered, false); } #else /* If the RX buffer empty */ if (rxbuf->head == rxbuf->tail) { /* Deactivate RX flow control. */ (void)uart_rxflowcontrol(dev, 0, false); } #endif #endif uart_givesem(&dev->recv.sem); return recvd; } /************************************************************************************ * Name: uart_ioctl ************************************************************************************/ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR uart_dev_t *dev = inode->i_private; /* Handle TTY-level IOCTLs here */ /* Let low-level driver handle the call first */ int ret = dev->ops->ioctl(filep, cmd, arg); /* The device ioctl() handler returns -ENOTTY when it doesn't know * how to handle the command. Check if we can handle it here. */ if (ret == -ENOTTY) { switch (cmd) { /* Get the number of bytes that may be read from the RX buffer * (without waiting) */ case FIONREAD: { int count; irqstate_t flags = enter_critical_section(); /* Determine the number of bytes available in the RX buffer */ if (dev->recv.tail <= dev->recv.head) { count = dev->recv.head - dev->recv.tail; } else { count = dev->recv.size - (dev->recv.tail - dev->recv.head); } leave_critical_section(flags); *(FAR int *)((uintptr_t)arg) = count; ret = 0; } break; /* Get the number of bytes that have been written to the TX buffer. */ case FIONWRITE: { int count; irqstate_t flags = enter_critical_section(); /* Determine the number of bytes waiting in the TX buffer */ if (dev->xmit.tail <= dev->xmit.head) { count = dev->xmit.head - dev->xmit.tail; } else { count = dev->xmit.size - (dev->xmit.tail - dev->xmit.head); } leave_critical_section(flags); *(FAR int *)((uintptr_t)arg) = count; ret = 0; } break; /* Get the number of free bytes in the TX buffer */ case FIONSPACE: { int count; irqstate_t flags = enter_critical_section(); /* Determine the number of bytes free in the TX buffer */ if (dev->xmit.head < dev->xmit.tail) { count = dev->xmit.tail - dev->xmit.head - 1; } else { count = dev->xmit.size - (dev->xmit.head - dev->xmit.tail) - 1; } leave_critical_section(flags); *(FAR int *)((uintptr_t)arg) = count; ret = 0; } break; } } #ifdef CONFIG_SERIAL_TERMIOS /* Append any higher level TTY flags */ else if (ret == OK) { switch (cmd) { case TCGETS: { FAR struct termios *termiosp = (FAR struct termios *)arg; if (!termiosp) { ret = -EINVAL; break; } /* And update with flags from this layer */ termiosp->c_iflag = dev->tc_iflag; termiosp->c_oflag = dev->tc_oflag; termiosp->c_lflag = dev->tc_lflag; } break; case TCSETS: { FAR struct termios *termiosp = (FAR struct termios *)arg; if (!termiosp) { ret = -EINVAL; break; } /* Update the flags we keep at this layer */ dev->tc_iflag = termiosp->c_iflag; dev->tc_oflag = termiosp->c_oflag; dev->tc_lflag = termiosp->c_lflag; } break; } } #endif return ret; } /**************************************************************************** * Name: uart_poll ****************************************************************************/ #ifndef CONFIG_DISABLE_POLL int uart_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup) { FAR struct inode *inode = filep->f_inode; FAR uart_dev_t *dev = inode->i_private; pollevent_t eventset; int ndx; int ret; int i; /* Some sanity checking */ #ifdef CONFIG_DEBUG_FEATURES if (!dev || !fds) { return -ENODEV; } #endif /* Are we setting up the poll? Or tearing it down? */ ret = uart_takesem(&dev->pollsem, true); if (ret < 0) { /* A signal received while waiting for access to the poll data * will abort the operation. */ return ret; } 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_SERIAL_NPOLLWAITERS; i++) { /* Find an available slot */ if (!dev->fds[i]) { /* Bind the poll structure and this slot */ dev->fds[i] = fds; fds->priv = &dev->fds[i]; break; } } if (i >= CONFIG_SERIAL_NPOLLWAITERS) { fds->priv = NULL; ret = -EBUSY; goto errout; } /* Should we immediately notify on any of the requested events? * First, check if the xmit buffer is full. * * Get exclusive access to the xmit buffer indices. NOTE: that we do not * let this wait be interrupted by a signal (we probably should, but that * would be a little awkward). */ eventset = 0; (void)uart_takesem(&dev->xmit.sem, false); ndx = dev->xmit.head + 1; if (ndx >= dev->xmit.size) { ndx = 0; } if (ndx != dev->xmit.tail) { eventset |= (fds->events & POLLOUT); } uart_givesem(&dev->xmit.sem); /* Check if the receive buffer is empty. * * Get exclusive access to the recv buffer indices. NOTE: that we do not * let this wait be interrupted by a signal (we probably should, but that * would be a little awkward). */ (void)uart_takesem(&dev->recv.sem, false); if (dev->recv.head != dev->recv.tail) { eventset |= (fds->events & POLLIN); } uart_givesem(&dev->recv.sem); #ifdef CONFIG_SERIAL_REMOVABLE /* Check if a removable device has been disconnected. */ if (dev->disconnected) { eventset |= (POLLERR | POLLHUP); } #endif if (eventset) { uart_pollnotify(dev, eventset); } } else if (fds->priv) { /* This is a request to tear down the poll. */ struct pollfd **slot = (struct pollfd **)fds->priv; #ifdef CONFIG_DEBUG_FEATURES if (!slot) { ret = -EIO; goto errout; } #endif /* Remove all memory of the poll setup */ *slot = NULL; fds->priv = NULL; } errout: uart_givesem(&dev->pollsem); return ret; } #endif /************************************************************************************ * Name: uart_close * * Description: * This routine is called when the serial port gets closed. * It waits for the last remaining data to be sent. * ************************************************************************************/ static int uart_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR uart_dev_t *dev = inode->i_private; irqstate_t flags; /* Get exclusive access to the close semaphore (to synchronize open/close operations. * NOTE: that we do not let this wait be interrupted by a signal. Technically, we * should, but almost no one every checks the return value from close() so we avoid * a potential memory leak by ignoring signals in this case. */ (void)uart_takesem(&dev->closesem, false); if (dev->open_count > 1) { dev->open_count--; uart_givesem(&dev->closesem); return OK; } /* There are no more references to the port */ dev->open_count = 0; /* Stop accepting input */ uart_disablerxint(dev); /* Now we wait for the transmit buffer to clear */ while (dev->xmit.head != dev->xmit.tail) { #ifndef CONFIG_DISABLE_SIGNALS usleep(HALF_SECOND_USEC); #else up_mdelay(HALF_SECOND_MSEC); #endif } /* And wait for the TX fifo to drain */ while (!uart_txempty(dev)) { #ifndef CONFIG_DISABLE_SIGNALS usleep(HALF_SECOND_USEC); #else up_mdelay(HALF_SECOND_MSEC); #endif } /* Free the IRQ and disable the UART */ flags = enter_critical_section(); /* Disable interrupts */ uart_detach(dev); /* Detach interrupts */ if (!dev->isconsole) /* Check for the serial console UART */ { uart_shutdown(dev); /* Disable the UART */ } leave_critical_section(flags); /* We need to re-initialize the semaphores if this is the last close * of the device, as the close might be caused by pthread_cancel() of * a thread currently blocking on any of them. */ sem_reset(&dev->xmitsem, 0); sem_reset(&dev->recvsem, 0); sem_reset(&dev->xmit.sem, 1); sem_reset(&dev->recv.sem, 1); #ifndef CONFIG_DISABLE_POLL sem_reset(&dev->pollsem, 1); #endif uart_givesem(&dev->closesem); return OK; } /************************************************************************************ * Name: uart_open * * Description: * This routine is called whenever a serial port is opened. * ************************************************************************************/ static int uart_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR uart_dev_t *dev = inode->i_private; uint8_t tmp; int ret; /* If the port is the middle of closing, wait until the close is finished. * If a signal is received while we are waiting, then return EINTR. */ ret = uart_takesem(&dev->closesem, true); if (ret < 0) { /* A signal received while waiting for the last close operation. */ return ret; } #ifdef CONFIG_SERIAL_REMOVABLE /* If the removable device is no longer connected, refuse to open the * device. We check this after obtaining the close semaphore because * we might have been waiting when the device was disconnected. */ if (dev->disconnected) { ret = -ENOTCONN; goto errout_with_sem; } #endif /* Start up serial port */ /* Increment the count of references to the device. */ tmp = dev->open_count + 1; if (tmp == 0) { /* More than 255 opens; uint8_t overflows to zero */ ret = -EMFILE; goto errout_with_sem; } /* Check if this is the first time that the driver has been opened. */ if (tmp == 1) { irqstate_t flags = enter_critical_section(); /* If this is the console, then the UART has already been initialized. */ if (!dev->isconsole) { /* Perform one time hardware initialization */ ret = uart_setup(dev); if (ret < 0) { leave_critical_section(flags); goto errout_with_sem; } } /* In any event, we do have to configure for interrupt driven mode of * operation. Attach the hardware IRQ(s). Hmm.. should shutdown() the * the device in the rare case that uart_attach() fails, tmp==1, and * this is not the console. */ ret = uart_attach(dev); if (ret < 0) { uart_shutdown(dev); leave_critical_section(flags); goto errout_with_sem; } /* Mark the io buffers empty */ dev->xmit.head = 0; dev->xmit.tail = 0; dev->recv.head = 0; dev->recv.tail = 0; /* Initialize termios state */ #ifdef CONFIG_SERIAL_TERMIOS dev->tc_iflag = 0; if (dev->isconsole) { /* Enable \n -> \r\n translation for the console */ dev->tc_oflag = OPOST | ONLCR; } else { dev->tc_oflag = 0; } #endif #ifdef CONFIG_SERIAL_DMA /* Notify DMA that there is free space in the RX buffer */ uart_dmarxfree(dev); #endif /* Enable the RX interrupt */ uart_enablerxint(dev); leave_critical_section(flags); } /* Save the new open count on success */ dev->open_count = tmp; errout_with_sem: uart_givesem(&dev->closesem); return ret; } /************************************************************************************ * Public Functions ************************************************************************************/ /************************************************************************************ * Name: uart_register * * Description: * Register serial console and serial ports. * ************************************************************************************/ int uart_register(FAR const char *path, FAR uart_dev_t *dev) { /* Initialize semaphores */ sem_init(&dev->xmit.sem, 0, 1); sem_init(&dev->recv.sem, 0, 1); sem_init(&dev->closesem, 0, 1); sem_init(&dev->xmitsem, 0, 0); sem_init(&dev->recvsem, 0, 0); #ifndef CONFIG_DISABLE_POLL sem_init(&dev->pollsem, 0, 1); #endif /* The recvsem and xmitsem are used for signaling and, hence, should not have * priority inheritance enabled. */ sem_setprotocol(&dev->xmitsem, SEM_PRIO_NONE); sem_setprotocol(&dev->recvsem, SEM_PRIO_NONE); /* Register the serial driver */ sinfo("Registering %s\n", path); return register_driver(path, &g_serialops, 0666, dev); } /************************************************************************************ * Name: uart_datareceived * * Description: * This function is called from uart_recvchars when new serial data is place in * the driver's circular buffer. This function will wake-up any stalled read() * operations that are waiting for incoming data. * ************************************************************************************/ void uart_datareceived(FAR uart_dev_t *dev) { /* Is there a thread waiting for read data? */ if (dev->recvwaiting) { /* Yes... wake it up */ dev->recvwaiting = false; (void)sem_post(&dev->recvsem); } /* Notify all poll/select waiters that they can read from the recv buffer */ uart_pollnotify(dev, POLLIN); } /************************************************************************************ * Name: uart_datasent * * Description: * This function is called from uart_xmitchars after serial data has been sent, * freeing up some space in the driver's circular buffer. This function will * wake-up any stalled write() operations that was waiting for space to buffer * outgoing data. * ************************************************************************************/ void uart_datasent(FAR uart_dev_t *dev) { /* Is there a thread waiting for space in xmit.buffer? */ if (dev->xmitwaiting) { /* Yes... wake it up */ dev->xmitwaiting = false; (void)sem_post(&dev->xmitsem); } /* Notify all poll/select waiters that they can write to xmit buffer */ uart_pollnotify(dev, POLLOUT); } /************************************************************************************ * Name: uart_connected * * Description: * Serial devices (like USB serial) can be removed. In that case, the "upper * half" serial driver must be informed that there is no longer a valid serial * channel associated with the driver. * * In this case, the driver will terminate all pending transfers wint ENOTCONN and * will refuse all further transactions while the "lower half" is disconnected. * The driver will continue to be registered, but will be in an unusable state. * * Conversely, the "upper half" serial driver needs to know when the serial * device is reconnected so that it can resume normal operations. * * Assumptions/Limitations: * This function may be called from an interrupt handler. * ************************************************************************************/ #ifdef CONFIG_SERIAL_REMOVABLE void uart_connected(FAR uart_dev_t *dev, bool connected) { irqstate_t flags; /* Is the device disconnected? Interrupts are disabled because this * function may be called from interrupt handling logic. */ flags = enter_critical_section(); dev->disconnected = !connected; if (!connected) { /* Yes.. wake up all waiting threads. Each thread should detect the * disconnection and return the ENOTCONN error. */ /* Is there a thread waiting for space in xmit.buffer? */ if (dev->xmitwaiting) { /* Yes... wake it up */ dev->xmitwaiting = false; (void)sem_post(&dev->xmitsem); } /* Is there a thread waiting for read data? */ if (dev->recvwaiting) { /* Yes... wake it up */ dev->recvwaiting = false; (void)sem_post(&dev->recvsem); } /* Notify all poll/select waiters that a hangup occurred */ uart_pollnotify(dev, (POLLERR | POLLHUP)); } leave_critical_section(flags); } #endif