/**************************************************************************** * drivers/serial/serial.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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Check watermark levels */ #if defined(CONFIG_SERIAL_IFLOWCONTROL) && \ defined(CONFIG_SERIAL_IFLOWCONTROL_WATERMARKS) # if CONFIG_SERIAL_IFLOWCONTROL_LOWER_WATERMARK < 1 # warning CONFIG_SERIAL_IFLOWCONTROL_LOWER_WATERMARK too small # endif # if CONFIG_SERIAL_IFLOWCONTROL_UPPER_WATERMARK > 99 # warning CONFIG_SERIAL_IFLOWCONTROL_UPPER_WATERMARK too large # endif # if CONFIG_SERIAL_IFLOWCONTROL_LOWER_WATERMARK >= CONFIG_SERIAL_IFLOWCONTROL_UPPER_WATERMARK # warning CONFIG_SERIAL_IFLOWCONTROL_LOWER_WATERMARK too large # warning Must be less than CONFIG_SERIAL_IFLOWCONTROL_UPPER_WATERMARK # endif #endif /* Timing */ #define POLL_DELAY_USEC 1000 /**************************************************************************** * Private Types ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Write support */ static int uart_putxmitchar(FAR uart_dev_t *dev, int ch, bool oktoblock); static inline ssize_t uart_irqwrite(FAR uart_dev_t *dev, FAR const char *buffer, size_t buflen); static int uart_tcdrain(FAR uart_dev_t *dev, bool cancelable, clock_t timeout); static int uart_tcsendbreak(FAR uart_dev_t *dev, FAR struct file *filep, unsigned int ms); /* Character driver methods */ 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); static int uart_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup); #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int uart_unlink(FAR struct inode *inode); #endif /**************************************************************************** * Public Function Prototypes ****************************************************************************/ #ifdef CONFIG_TTY_LAUNCH_ENTRY /* Lanch program entry, this must be supplied by the application. */ int CONFIG_TTY_LAUNCH_ENTRYPOINT(int argc, FAR char *argv[]); #endif /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_serialops = { uart_open, /* open */ uart_close, /* close */ uart_read, /* read */ uart_write, /* write */ NULL, /* seek */ uart_ioctl, /* ioctl */ NULL, /* mmap */ NULL, /* truncate */ uart_poll /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , uart_unlink /* unlink */ #endif }; #ifdef CONFIG_TTY_LAUNCH static struct work_s g_serial_work; #endif /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * 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; break; } /* 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 { /* 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_TXDMA uart_dmatxavail(dev); #endif uart_enabletxint(dev); ret = nxsem_wait(&dev->xmitsem); 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_putc ****************************************************************************/ static inline void uart_putc(FAR uart_dev_t *dev, int ch) { while (!uart_txready(dev)) { } uart_send(dev, ch); } /**************************************************************************** * 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++; /* 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) { uart_putc(dev, '\r'); } } /* Output the character, using the low-level direct UART interfaces */ uart_putc(dev, ch); } return ret; } /**************************************************************************** * Name: uart_tcdrain * * Description: * Block further TX input. * Wait until all data has been transferred from the TX buffer and * until the hardware TX FIFOs are empty. * ****************************************************************************/ static int uart_tcdrain(FAR uart_dev_t *dev, bool cancelable, clock_t timeout) { int ret; /* tcdrain is a cancellation point */ if (cancelable && enter_cancellation_point()) { #ifdef CONFIG_CANCELLATION_POINTS /* If there is a pending cancellation, then do not perform * the wait. Exit now with ECANCELED. */ leave_cancellation_point(); return -ECANCELED; #endif } /* Get exclusive access to the to dev->tmit. We cannot permit new data to * be written while we are trying to flush the old data. * * A signal received while waiting for access to the xmit.head will abort * the operation with EINTR. */ ret = nxmutex_lock(&dev->xmit.lock); if (ret >= 0) { irqstate_t flags; clock_t start; /* Trigger emission to flush the contents of the tx buffer */ flags = enter_critical_section(); #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) { dev->xmit.tail = dev->xmit.head; /* Drop the buffered TX data */ ret = -ENOTCONN; } else #endif { /* Continue waiting while the TX buffer is not empty. * * NOTE: There is no timeout on the following loop. In * situations were this loop could hang (with hardware flow * control, as an example), the caller should call * tcflush() first to discard this buffered Tx data. */ ret = OK; while (ret >= 0 && dev->xmit.head != dev->xmit.tail) { /* 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. We may have to wait several * times for the TX buffer to be entirely emptied. * * NOTE that interrupts will be re-enabled while we wait for * the semaphore. */ #ifdef CONFIG_SERIAL_TXDMA uart_dmatxavail(dev); #endif uart_enabletxint(dev); ret = nxsem_wait(&dev->xmitsem); uart_disabletxint(dev); } } leave_critical_section(flags); /* The TX buffer is empty (or an error occurred). But there still may * be data in the UART TX FIFO. We get no asynchronous indication of * this event, so we have to do a busy wait poll. */ /* Set up for the timeout * * REVISIT: This is a kludge. The correct fix would be add an * interface to the lower half driver so that the tcflush() operation * all also cause the lower half driver to clear and reset the Tx FIFO. */ start = clock_systime_ticks(); if (ret >= 0) { while (!uart_txempty(dev)) { clock_t elapsed; nxsig_usleep(POLL_DELAY_USEC); /* Check for a timeout */ elapsed = clock_systime_ticks() - start; if (elapsed >= timeout) { nxmutex_unlock(&dev->xmit.lock); return -ETIMEDOUT; } } } nxmutex_unlock(&dev->xmit.lock); } if (cancelable) { leave_cancellation_point(); } return ret; } /**************************************************************************** * Name: uart_tcsendbreak * * Description: * Request a serial line Break by calling the lower half driver's * BSD-compatible Break IOCTLs TIOCSBRK and TIOCCBRK, with a sleep of the * specified duration between them. * * Input Parameters: * dev - Serial device. * filep - Required for issuing lower half driver IOCTL call. * ms - If non-zero, duration of the Break in milliseconds; if * zero, duration is 400 milliseconds. * * Returned Value: * 0 on success or a negated errno value on failure. * ****************************************************************************/ static int uart_tcsendbreak(FAR uart_dev_t *dev, FAR struct file *filep, unsigned int ms) { int ret; /* REVISIT: Do we need to perform the equivalent of tcdrain() before * beginning the Break to avoid corrupting the transmit data? If so, note * that just calling uart_tcdrain() here would create a race condition, * since new transmit data could be written after uart_tcdrain() returns * but before we re-acquire the dev->xmit.lock here. Therefore, we would * need to refactor the functional portion of uart_tcdrain() to a separate * function and call it from both uart_tcdrain() and uart_tcsendbreak() * in critical section and with xmit lock already held. */ if (dev->ops->ioctl) { ret = nxmutex_lock(&dev->xmit.lock); if (ret >= 0) { /* Request lower half driver to start the Break */ ret = dev->ops->ioctl(filep, TIOCSBRK, 0); if (ret >= 0) { /* Wait 400 ms or the requested Break duration */ nxsig_usleep((ms == 0) ? 400000 : ms * 1000); /* Request lower half driver to end the Break */ ret = dev->ops->ioctl(filep, TIOCCBRK, 0); } } nxmutex_unlock(&dev->xmit.lock); } else { /* With no lower half IOCTL, we cannot request Break at all. */ ret = -ENOTTY; } return ret; } /**************************************************************************** * 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 = nxmutex_lock(&dev->closelock); 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_lock; } #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_lock; } /* 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_lock; } } /* 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) { if (!dev->isconsole) { uart_shutdown(dev); } leave_critical_section(flags); goto errout_with_lock; } #ifdef CONFIG_SERIAL_RXDMA /* 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_lock: nxmutex_unlock(&dev->closelock); return ret; } /**************************************************************************** * 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. */ nxmutex_lock(&dev->closelock); if (dev->open_count > 1) { dev->open_count--; nxmutex_unlock(&dev->closelock); return OK; } /* There are no more references to the port */ dev->open_count = 0; /* Stop accepting input */ uart_disablerxint(dev); /* Prevent blocking if the device is opened with O_NONBLOCK */ if ((filep->f_oflags & O_NONBLOCK) == 0) { /* Now we wait for the transmit buffer(s) to clear */ uart_tcdrain(dev, false, 4 * TICK_PER_SEC); } /* Free the IRQ and disable the UART */ flags = enter_critical_section(); /* Disable interrupts */ uart_detach(dev); /* Detach interrupts */ /* Check for the serial console UART */ if (!dev->isconsole) { uart_shutdown(dev); /* Disable the UART */ } leave_critical_section(flags); /* Wake up read and poll functions */ uart_datareceived(dev); /* 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. */ uart_reset_sem(dev); if (dev->unlinked) { nxmutex_unlock(&dev->closelock); nxmutex_destroy(&dev->xmit.lock); nxmutex_destroy(&dev->recv.lock); nxmutex_destroy(&dev->closelock); nxmutex_destroy(&dev->polllock); nxsem_destroy(&dev->xmitsem); nxsem_destroy(&dev->recvsem); uart_release(dev); return OK; } nxmutex_unlock(&dev->closelock); return OK; } /**************************************************************************** * 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; bool echoed = false; int16_t tail; char ch; int ret; /* Only one user can access rxbuf->tail at a time */ ret = nxmutex_lock(&dev->recv.lock); if (ret < 0) { /* A signal received while waiting for access to the recv.tail 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 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; /* 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. */ /* Store the received character */ *buffer++ = ch; recvd++; if (dev->tc_lflag & ECHO) { /* Check for the beginning of a VT100 escape sequence, 3 byte */ if (ch == ASCII_ESC) { /* Mark that we should skip 2 more bytes */ dev->escape = 2; continue; } else if (dev->escape == 2 && ch != ASCII_LBRACKET) { /* It's not an [x 3 byte sequence, show it */ dev->escape = 0; } else if (dev->escape > 0) { /* Skipping character count down */ dev->escape--; continue; } /* Echo if the character is not a control byte */ if (!iscntrl(ch & 0xff) || ch == '\n') { if (ch == '\n') { uart_putxmitchar(dev, '\r', true); } uart_putxmitchar(dev, ch, true); /* Mark the tx buffer have echoed content here, * to avoid the tx buffer is empty such as special escape * sequence received, but enable the tx interrupt. */ echoed = true; } } } #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; } else if (filep->f_inode == 0) { /* File has been closed. * Descriptor is not valid. */ recvd = -EBADFD; 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 all interrupts and test again... */ flags = enter_critical_section(); /* Disable Rx interrupts and test again... */ uart_disablerxint(dev); /* If the Rx ring buffer still empty? Bytes may have been added * between the last time that we checked and when we disabled * interrupts. */ if (rxbuf->head == rxbuf->tail) { /* Yes.. the buffer is still empty. We will need to wait for * additional data to be received. */ #ifdef CONFIG_SERIAL_RXDMA /* Notify DMA that there is free space in the RX buffer */ uart_dmarxfree(dev); #endif /* Wait with the RX interrupt re-enabled. All interrupts are * disabled briefly to assure that the following operations * are atomic. */ /* Re-enable UART Rx interrupts */ uart_enablerxint(dev); /* Check again if the RX buffer is empty. The UART driver * might have buffered data received between disabling the * RX interrupt and entering the critical section. Some * drivers (looking at you, cdcacm...) will push the buffer * to the receive queue during uart_enablerxint(). * Just continue processing the RX queue if this happens. */ if (rxbuf->head != rxbuf->tail) { leave_critical_section(flags); continue; } #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 enabled. NuttX will * automatically re-enable global interrupts when this * thread goes to sleep. */ #ifdef CONFIG_SERIAL_TERMIOS dev->minrecv = MIN(buflen - recvd, dev->minread - recvd); if (dev->timeout) { nxmutex_unlock(&dev->recv.lock); ret = nxsem_tickwait(&dev->recvsem, DSEC2TICK(dev->timeout)); } else #endif { nxmutex_unlock(&dev->recv.lock); ret = nxsem_wait(&dev->recvsem); } nxmutex_lock(&dev->recv.lock); #ifdef CONFIG_SERIAL_TERMIOS dev->minrecv = dev->minread; #endif } 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 : ret; #else recvd = ret; #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. */ leave_critical_section(flags); uart_enablerxint(dev); } } } if (echoed) { #ifdef CONFIG_SERIAL_TXDMA uart_dmatxavail(dev); #endif uart_enabletxint(dev); } #ifdef CONFIG_SERIAL_RXDMA /* Notify DMA that there is free space in the RX buffer */ flags = enter_critical_section(); uart_dmarxfree(dev); leave_critical_section(flags); #endif /* RX interrupt could be disabled by RX buffer overflow. Enable it now. */ uart_enablerxint(dev); #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. */ uart_rxflowcontrol(dev, nbuffered, false); } #else /* Is the RX buffer empty? */ if (rxbuf->head == rxbuf->tail) { /* Deactivate RX flow control. */ uart_rxflowcontrol(dev, 0, false); } #endif #endif nxmutex_unlock(&dev->recv.lock); return recvd; } /**************************************************************************** * 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 serial 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() || sched_idletask()) { irqstate_t flags; #ifdef CONFIG_SERIAL_REMOVABLE /* If the removable device is no longer connected, refuse to write to * the device. */ if (dev->disconnected) { return -ENOTCONN; } #endif flags = enter_critical_section(); ret = uart_irqwrite(dev, buffer, buflen); leave_critical_section(flags); return ret; } /* Only one user can access dev->xmit.head at a time */ ret = nxmutex_lock(&dev->xmit.lock); 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.lock because the * disconnection event might have occurred while we were waiting for * access to the transmit buffers. */ if (dev->disconnected) { nxmutex_unlock(&dev->xmit.lock); 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; /* 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); } /* Specifically not handled: * * OXTABS - primarily a full-screen terminal optimization * ONOEOT - Unix interoperability hack * OLCUC - Not specified by POSIX * ONOCR - low-speed interactive optimization */ } /* Put the character into the transmit buffer */ if (ret >= 0) { 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_TXDMA uart_dmatxavail(dev); #endif uart_enabletxint(dev); } nxmutex_unlock(&dev->xmit.lock); return nwritten; } /**************************************************************************** * 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 ? dev->ops->ioctl(filep, cmd, arg) : -ENOTTY; /* 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; case TCFLSH: { /* Empty the tx/rx buffers */ irqstate_t flags = enter_critical_section(); if (arg == TCIFLUSH || arg == TCIOFLUSH) { dev->recv.tail = dev->recv.head; #ifdef CONFIG_SERIAL_IFLOWCONTROL /* De-activate RX flow control. */ uart_rxflowcontrol(dev, 0, false); #endif } if (arg == TCOFLUSH || arg == TCIOFLUSH) { dev->xmit.tail = dev->xmit.head; /* Inform any waiters there there is space available. */ uart_datasent(dev); } leave_critical_section(flags); ret = 0; } break; case TCDRN: { ret = uart_tcdrain(dev, true, 10 * TICK_PER_SEC); } break; case TCSBRK: { /* Non-standard Break specifies duration in milliseconds */ ret = uart_tcsendbreak(dev, filep, arg); } break; case TCSBRKP: { /* POSIX Break specifies duration in units of 100ms */ ret = uart_tcsendbreak(dev, filep, arg * 100); } break; #if defined(CONFIG_TTY_SIGINT) || defined(CONFIG_TTY_SIGTSTP) /* Make the controlling terminal of the calling process */ case TIOCSCTTY: { /* Save the PID of the recipient of the SIGINT signal. */ if ((int)arg < 0 || dev->pid >= 0) { ret = -EINVAL; } else { dev->pid = (pid_t)arg; ret = 0; } } break; case TIOCNOTTY: { dev->pid = INVALID_PROCESS_ID; ret = 0; } break; #endif } } /* Append any higher level TTY flags */ if (ret == OK || ret == -ENOTTY) { switch (cmd) { case TCGETS: { FAR struct termios *termiosp = (FAR struct termios *) (uintptr_t)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; #ifdef CONFIG_SERIAL_TERMIOS termiosp->c_cc[VTIME] = dev->timeout; termiosp->c_cc[VMIN] = dev->minread; #endif ret = 0; } break; case TCSETS: { FAR struct termios *termiosp = (FAR struct termios *) (uintptr_t)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; #ifdef CONFIG_SERIAL_TERMIOS dev->timeout = termiosp->c_cc[VTIME]; dev->minread = termiosp->c_cc[VMIN]; dev->minrecv = dev->minread; #endif ret = 0; } break; } } return ret; } /**************************************************************************** * Name: uart_poll ****************************************************************************/ static 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 == NULL || fds == NULL) { return -ENODEV; } #endif /* Are we setting up the poll? Or tearing it down? */ ret = nxmutex_lock(&dev->polllock); 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; nxmutex_lock(&dev->xmit.lock); ndx = dev->xmit.head + 1; if (ndx >= dev->xmit.size) { ndx = 0; } if (ndx != dev->xmit.tail) { eventset |= POLLOUT; } nxmutex_unlock(&dev->xmit.lock); /* 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). */ nxmutex_lock(&dev->recv.lock); if (dev->recv.head != dev->recv.tail) { eventset |= POLLIN; } nxmutex_unlock(&dev->recv.lock); #ifdef CONFIG_SERIAL_REMOVABLE /* Check if a removable device has been disconnected. */ if (dev->disconnected) { eventset |= (POLLERR | POLLHUP); } #endif poll_notify(&fds, 1, eventset); } else if (fds->priv != NULL) { /* This is a request to tear down the poll. */ FAR struct pollfd **slot = (FAR 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: nxmutex_unlock(&dev->polllock); return ret; } /**************************************************************************** * Name: uart_unlink ****************************************************************************/ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int uart_unlink(FAR struct inode *inode) { FAR uart_dev_t *dev; int ret; DEBUGASSERT(inode->i_private != NULL); dev = inode->i_private; ret = nxmutex_lock(&dev->closelock); if (ret < 0) { /* A signal received while waiting for the last close operation. */ return ret; } if (dev->open_count <= 0) { nxmutex_unlock(&dev->closelock); nxmutex_destroy(&dev->xmit.lock); nxmutex_destroy(&dev->recv.lock); nxmutex_destroy(&dev->closelock); nxmutex_destroy(&dev->polllock); nxsem_destroy(&dev->xmitsem); nxsem_destroy(&dev->recvsem); uart_release(dev); return OK; } dev->unlinked = true; nxmutex_unlock(&dev->closelock); return OK; } #endif /**************************************************************************** * Name: uart_nxsched_foreach_cb ****************************************************************************/ #ifdef CONFIG_TTY_LAUNCH static void uart_launch_foreach(FAR struct tcb_s *tcb, FAR void *arg) { #ifdef CONFIG_TTY_LAUNCH_ENTRY if (!strcmp(tcb->name, CONFIG_TTY_LAUNCH_ENTRYNAME)) #else if (!strcmp(tcb->name, CONFIG_TTY_LAUNCH_FILEPATH)) #endif { *(FAR int *)arg = 1; } } static void uart_launch_worker(void *arg) { #ifdef CONFIG_TTY_LAUNCH_ARGS FAR char *const argv[] = { CONFIG_TTY_LAUNCH_ARGS, NULL, }; #else FAR char *const *argv = NULL; #endif int found = 0; nxsched_foreach(uart_launch_foreach, &found); if (!found) { posix_spawnattr_t attr; posix_spawnattr_init(&attr); attr.priority = CONFIG_TTY_LAUNCH_PRIORITY; attr.stacksize = CONFIG_TTY_LAUNCH_STACKSIZE; #ifdef CONFIG_TTY_LAUNCH_ENTRY task_spawn(CONFIG_TTY_LAUNCH_ENTRYNAME, CONFIG_TTY_LAUNCH_ENTRYPOINT, NULL, &attr, argv, NULL); #else exec_spawn(CONFIG_TTY_LAUNCH_FILEPATH, argv, NULL, NULL, 0, NULL, &attr); #endif posix_spawnattr_destroy(&attr); } } static void uart_launch(void) { work_queue(HPWORK, &g_serial_work, uart_launch_worker, NULL, 0); } #endif static void uart_wakeup(FAR sem_t *sem) { int sval; if (nxsem_get_value(sem, &sval) != OK) { return; } /* Yes... wake up all waiting threads */ while (sval++ < 1) { nxsem_post(sem); } } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: uart_register * * Description: * Register serial console and serial ports. * ****************************************************************************/ int uart_register(FAR const char *path, FAR uart_dev_t *dev) { #if defined(CONFIG_TTY_SIGINT) || defined(CONFIG_TTY_SIGTSTP) /* Initialize of the task that will receive SIGINT signals. */ dev->pid = INVALID_PROCESS_ID; #endif /* If this UART is a serial console */ if (dev->isconsole) { /* Enable signals and echo by default */ dev->tc_lflag |= ISIG | ECHO; /* Enable \n -> \r\n translation for the console */ dev->tc_oflag = OPOST | ONLCR; /* Convert CR to LF by default for console */ dev->tc_iflag |= ICRNL; /* Clear escape counter */ dev->escape = 0; } /* Initialize mutex & semaphores */ nxmutex_init(&dev->xmit.lock); nxmutex_init(&dev->recv.lock); nxmutex_init(&dev->closelock); nxsem_init(&dev->xmitsem, 0, 0); nxsem_init(&dev->recvsem, 0, 0); nxmutex_init(&dev->polllock); #ifdef CONFIG_SERIAL_TERMIOS dev->timeout = 0; dev->minread = 1; #endif /* Register the serial driver */ #ifdef CONFIG_SERIAL_GDBSTUB if (strcmp(path, CONFIG_SERIAL_GDBSTUB_PATH) == 0) { return uart_gdbstub_register(dev); } #endif 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) { /* Notify all poll/select waiters that they can read from the recv buffer */ poll_notify(dev->fds, CONFIG_SERIAL_NPOLLWAITERS, POLLIN); /* Is there a thread waiting for read data? */ uart_wakeup(&dev->recvsem); #if defined(CONFIG_PM) && defined(CONFIG_SERIAL_CONSOLE) /* Call pm_activity when characters are received on the console device */ if (dev->isconsole) { pm_activity(CONFIG_SERIAL_PM_ACTIVITY_DOMAIN, CONFIG_SERIAL_PM_ACTIVITY_PRIORITY); } #endif } /**************************************************************************** * 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) { /* Notify all poll/select waiters that they can write to xmit buffer */ poll_notify(dev->fds, CONFIG_SERIAL_NPOLLWAITERS, POLLOUT); /* Is there a thread waiting for space in xmit.buffer? */ uart_wakeup(&dev->xmitsem); } /**************************************************************************** * 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) { /* Notify all poll/select waiters that a hangup occurred */ poll_notify(dev->fds, CONFIG_SERIAL_NPOLLWAITERS, POLLERR | POLLHUP); /* 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? */ uart_wakeup(&dev->xmitsem); /* Is there a thread waiting for read data? */ uart_wakeup(&dev->recvsem); } leave_critical_section(flags); } #endif /**************************************************************************** * Name: uart_reset_sem * * Description: * This function is called when need reset uart semaphore, this may used in * kill one process, but this process was reading/writing with the * semaphore. * ****************************************************************************/ void uart_reset_sem(FAR uart_dev_t *dev) { nxsem_reset(&dev->xmitsem, 0); nxsem_reset(&dev->recvsem, 0); nxmutex_reset(&dev->xmit.lock); nxmutex_reset(&dev->recv.lock); nxmutex_reset(&dev->polllock); } /**************************************************************************** * Name: uart_check_special * * Description: * Check if the SIGINT or SIGTSTP character is in the contiguous Rx DMA * buffer region. The first signal associated with the first such * character is returned. * * If there multiple such characters in the buffer, only the signal * associated with the first is returned (this a bug!) * * Returned Value: * 0 if a signal-related character does not appear in the. Otherwise, * SIGKILL or SIGTSTP may be returned to indicate the appropriate signal * action. * ****************************************************************************/ #if defined(CONFIG_TTY_SIGINT) || defined(CONFIG_TTY_SIGTSTP) || \ defined(CONFIG_TTY_FORCE_PANIC) || defined(CONFIG_TTY_LAUNCH) int uart_check_special(FAR uart_dev_t *dev, FAR const char *buf, size_t size) { size_t i; if ((dev->tc_lflag & ISIG) == 0) { return 0; } for (i = 0; i < size; i++) { #ifdef CONFIG_TTY_FORCE_PANIC if (buf[i] == CONFIG_TTY_FORCE_PANIC_CHAR) { PANIC(); return 0; } #endif #ifdef CONFIG_TTY_LAUNCH if (buf[i] == CONFIG_TTY_LAUNCH_CHAR) { uart_launch(); return 0; } #endif #ifdef CONFIG_TTY_SIGINT if (dev->pid > 0 && buf[i] == CONFIG_TTY_SIGINT_CHAR) { return SIGINT; } #endif #ifdef CONFIG_TTY_SIGTSTP if (dev->pid > 0 && buf[i] == CONFIG_TTY_SIGTSTP_CHAR) { return SIGTSTP; } #endif } return 0; } #endif