diff options
Diffstat (limited to 'nuttx/drivers/serial/serial.c')
-rw-r--r-- | nuttx/drivers/serial/serial.c | 855 |
1 files changed, 855 insertions, 0 deletions
diff --git a/nuttx/drivers/serial/serial.c b/nuttx/drivers/serial/serial.c new file mode 100644 index 000000000..ea4ceb0c0 --- /dev/null +++ b/nuttx/drivers/serial/serial.c @@ -0,0 +1,855 @@ +/************************************************************************************ + * drivers/serial/serial.c + * + * Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ************************************************************************************/ + +/************************************************************************************ + * Included Files + ************************************************************************************/ + +#include <nuttx/config.h> + +#include <sys/types.h> +#include <sys/ioctl.h> +#include <stdint.h> +#include <stdbool.h> +#include <unistd.h> +#include <semaphore.h> +#include <string.h> +#include <fcntl.h> +#include <poll.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/irq.h> +#include <nuttx/arch.h> +#include <nuttx/fs/fs.h> +#include <nuttx/serial/serial.h> + +/************************************************************************************ + * 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 Variables + ************************************************************************************/ + +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 +}; + +/************************************************************************************ + * Private Functions + ************************************************************************************/ + +/************************************************************************************ + * Name: uart_takesem + ************************************************************************************/ + +static void uart_takesem(FAR sem_t *sem) +{ + while (sem_wait(sem) != 0) + { + /* The only case that an error should occur here is if + * the wait was awakened by a signal. + */ + + ASSERT(get_errno() == EINTR); + } +} + +/************************************************************************************ + * 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) + { + fds->revents |= (fds->events & eventset); + if (fds->revents != 0) + { + fvdbg("Report events: %02x\n", fds->revents); + sem_post(fds->sem); + } + } + } +} +#else +# define uart_pollnotify(dev,event) +#endif + +/************************************************************************************ + * Name: uart_putxmitchar + ************************************************************************************/ + +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); + } + } +} + +/************************************************************************************ + * Name: uart_irqwrite + ************************************************************************************/ + +static 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++; + uart_putc(ch); + + /* If this is the console, then we should replace LF with LF-CR */ + + if (ch == '\n') + { + uart_putc('\r'); + } + } + + 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 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->termios_s.c_oflag && ONLCR) && ch == '\n') + { + uart_putxmitchar(dev, '\r'); + } + } + + if (dev->xmit.head != dev->xmit.tail) + { + uart_enabletxint(dev); + } + + uart_givesem(&dev->xmit.sem); + return ret; +} + +/************************************************************************************ + * 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; + 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; +} + +/************************************************************************************ + * 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); + /* Append any higher level TTY flags */ + switch (cmd) + { + case TCGETS: + { + struct termios *termiosp = (struct termios*)arg; + + if (!termiosp) + { + ret = -EINVAL; + break; + } + + /* Fetch the out flags */ + termiosp->c_oflag = dev->termios_s.c_oflag; + /* Fetch the in flags */ + termiosp->c_iflag = dev->termios_s.c_iflag; + } + break; + + case TCSETS: + { + struct termios *termiosp = (struct termios*)arg; + + if (!termiosp) + { + ret = -EINVAL; + break; + } + + /* Set the out flags */ + dev->termios_s.c_oflag = termiosp->c_oflag; + /* Set the in flags */ + dev->termios_s.c_iflag = termiosp->c_iflag; + } + break; + } + 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 = 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; +} +#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; + + 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; + } + +/************************************************************************************ + * Name: uart_open + * + * Description: + * This routine is called whenever a serial port is opened. + * + ************************************************************************************/ + +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; +} + +/************************************************************************************ + * Public Functions + ************************************************************************************/ + +/************************************************************************************ + * Name: uart_register + * + * Description: + * Register serial console and serial ports. + * + ************************************************************************************/ + +int uart_register(FAR const char *path, FAR uart_dev_t *dev) +{ + 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 + /* Setup termios flags */ + memset(&dev->termios_s, 0, sizeof(dev->termios_s)); + if (dev->isconsole == true) + { + /* Device is console, set up termios flags */ + dev->termios_s.c_oflag |= ONLCR; + } + + dbg("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) +{ + /* Awaken any awaiting read() operations */ + + if (dev->recvwaiting) + { + 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) +{ + if (dev->xmitwaiting) + { + dev->xmitwaiting = false; + (void)sem_post(&dev->xmitsem); + } + + /* Notify all poll/select waiters that they can write to xmit buffer */ + + uart_pollnotify(dev, POLLOUT); +} + + |