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; uart_takesem(&dev->closesem); 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 = irqsave(); /* Disable interrupts */ uart_detach(dev); /* Detach interrupts */ if (!dev->isconsole) /* Check for the serial console UART */ { uart_shutdown(dev); /* Disable the UART */ } irqrestore(flags); uart_givesem(&dev->closesem); return OK; }
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 int uart_open(FAR struct file *filep) { struct inode *inode = filep->f_inode; uart_dev_t *dev = inode->i_private; uint8_t tmp; int ret = OK; /* If the port is the middle of closing, wait until the close is finished */ uart_takesem(&dev->closesem); /* 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 = irqsave(); /* 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) { irqrestore(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); irqrestore(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; /* Enable the RX interrupt */ uart_enablerxint(dev); irqrestore(flags); } /* Save the new open count on success */ dev->open_count = tmp; errout_with_sem: uart_givesem(&dev->closesem); return ret; }
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 = OK; int i; /* Some sanity checking */ #if CONFIG_DEBUG if (!dev || !fds) { return -ENODEV; } #endif /* Are we setting up the poll? Or tearing it down? */ uart_takesem(&dev->pollsem); 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 immediately notify on any of the requested events? * First, check if the xmit buffer is full. */ eventset = 0; uart_takesem(&dev->xmit.sem); ndx = dev->xmit.head + 1; if (ndx >= dev->xmit.size) { ndx = 0; } if (ndx != dev->xmit.tail) { eventset |= POLLOUT; } uart_givesem(&dev->xmit.sem); /* Check if the receive buffer is empty */ uart_takesem(&dev->recv.sem); if (dev->recv.head != dev->recv.tail) { eventset |= POLLIN; } uart_givesem(&dev->recv.sem); 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 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; }
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; irqstate_t flags; ssize_t recvd = 0; int16_t tail; /* Only one user can be accessing dev->recv.tail at once */ uart_takesem(&dev->recv.sem); /* 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 (recvd < buflen) { /* Check if there is more data to return in the circular buffer. * NOTE: Rx interrupt handling logic may aynchronously 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 = dev->recv.tail; if (dev->recv.head != tail) { /* Take the next character from the tail of the buffer */ *buffer++ = dev->recv.buffer[tail]; recvd++; /* Increment the tail index. Most operations are done using the * local variable 'tail' so that the final dev->recv.tail update * is atomic. */ if (++tail >= dev->recv.size) { tail = 0; } dev->recv.tail = tail; } #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) { /* 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) { /* 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 (dev->recv.head == dev->recv.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 = irqsave(); dev->recvwaiting = true; uart_enablerxint(dev); /* Now wait with the Rx interrupt re-enabled. NuttX will * automatically re-enable global interrupts when this * thread goes to sleep. */ uart_takesem(&dev->recvsem); irqrestore(flags); } 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); } } } uart_givesem(&dev->recv.sem); return recvd; }
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 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 = irqsave(); /* Disable interrupts */ uart_detach(dev); /* Detach interrupts */ if (!dev->isconsole) /* Check for the serial console UART */ { uart_shutdown(dev); /* Disable the UART */ } irqrestore(flags); uart_givesem(&dev->closesem); 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; /* 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; }
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 */ #if CONFIG_DEBUG 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 |= 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 |= POLLIN; } uart_givesem(&dev->recv.sem); 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 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; }
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; irqstate_t flags; ssize_t recvd = 0; int16_t tail; int ret; char ch; /* Only one user can access dev->recv.tail at a time */ ret = uart_takesem(&dev->recv.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 (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 aynchronously 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 = dev->recv.tail; if (dev->recv.head != tail) { /* Take the next character from the tail of the buffer */ ch = dev->recv.buffer[tail]; /* Increment the tail index. Most operations are done using the * local variable 'tail' so that the final dev->recv.tail update * is atomic. */ if (++tail >= dev->recv.size) { tail = 0; } dev->recv.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 (dev->recv.head == dev->recv.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 = irqsave(); 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); } irqrestore(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_IFLOWCONTROL if (dev->recv.head == dev->recv.tail) { /* We might leave Rx interrupt disabled if full recv buffer was read * empty. Enable Rx interrupt to make sure that more input is received. */ uart_enablerxint(dev); } #endif uart_givesem(&dev->recv.sem); return recvd; }
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 int uart_open(FAR struct file *filep) { struct inode *inode = filep->f_inode; 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 = irqsave(); /* 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) { irqrestore(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); irqrestore(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; /* Initialise termios state */ #ifdef CONFIG_SERIAL_TERMIOS dev->tc_iflag = 0; if (dev->isconsole == true) { /* Enable \n -> \r\n translation for the console */ dev->tc_oflag = OPOST | ONLCR; } else { dev->tc_oflag = 0; } #endif /* Enable the RX interrupt */ uart_enablerxint(dev); irqrestore(flags); } /* Save the new open count on success */ dev->open_count = tmp; errout_with_sem: uart_givesem(&dev->closesem); 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; 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; }
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 = irqsave(); /* Disable interrupts */ uart_detach(dev); /* Detach interrupts */ if (!dev->isconsole) /* Check for the serial console UART */ { uart_shutdown(dev); /* Disable the UART */ } irqrestore(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. * * REVISIT: This logic *only* works in the case where the cancelled * thread had the only reference to the serial driver. If there other * references, then the this logic will not be executed and the * semaphore count will still be incorrect. */ sem_reinit(&dev->xmitsem, 0, 0); sem_reinit(&dev->recvsem, 0, 0); sem_reinit(&dev->xmit.sem, 0, 1); sem_reinit(&dev->recv.sem, 0, 1); #ifndef CONFIG_DISABLE_POLL sem_reinit(&dev->pollsem, 0, 1); #endif uart_givesem(&dev->closesem); return OK; }