diff options
Diffstat (limited to 'nuttx/drivers')
-rw-r--r-- | nuttx/drivers/Makefile | 2 | ||||
-rw-r--r-- | nuttx/drivers/serial.c | 578 |
2 files changed, 579 insertions, 1 deletions
diff --git a/nuttx/drivers/Makefile b/nuttx/drivers/Makefile index 8d687a67c..f992f5837 100644 --- a/nuttx/drivers/Makefile +++ b/nuttx/drivers/Makefile @@ -40,7 +40,7 @@ MKDEP = $(TOPDIR)/tools/mkdeps.sh ASRCS = AOBJS = $(ASRCS:.S=$(OBJEXT)) -CSRCS = dev_null.c +CSRCS = dev_null.c serial.c COBJS = $(CSRCS:.c=$(OBJEXT)) SRCS = $(ASRCS) $(CSRCS) diff --git a/nuttx/drivers/serial.c b/nuttx/drivers/serial.c new file mode 100644 index 000000000..fd0e5b1b7 --- /dev/null +++ b/nuttx/drivers/serial.c @@ -0,0 +1,578 @@ +/************************************************************************************ + * serial.c + * + * Copyright (C) 2007 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 Gregory Nutt 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 <unistd.h> +#include <semaphore.h> +#include <string.h> +#include <errno.h> +#include <debug.h> +#include <nuttx/irq.h> +#include <nuttx/arch.h> +#include <nuttx/fs.h> +#include <nuttx/serial.h> + +/************************************************************************************ + * Definitions + ************************************************************************************/ + +#ifdef CONFIG_HAVE_LOWPUTC +# define uart_putc(ch) up_lowputc(ch); +#else +# define uart_putc(ch) up_putc(ch); +#endif + +/************************************************************************************ + * Private Types + ************************************************************************************/ + +/************************************************************************************ + * Private Function Prototypes + ************************************************************************************/ + +static int uart_open(struct file *filep); +static int uart_close(struct file *filep); +static ssize_t uart_read(struct file *filep, char *buffer, size_t buflen); +static ssize_t uart_write(struct file *filep, const char *buffer, size_t buflen); +static int uart_ioctl(struct file *filep, int cmd, unsigned long arg); + +/************************************************************************************ + * Private Variables + ************************************************************************************/ + +struct file_operations g_serialops = +{ + uart_open, /* open */ + uart_close, /* close */ + uart_read, /* read */ + uart_write, /* write */ + uart_ioctl /* ioctl */ +}; + +/************************************************************************************ + * Private Functions + ************************************************************************************/ + +/************************************************************************************ + * Name: uart_waittxfifonotfull + ************************************************************************************/ + +#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_SERIAL_INTS) +static inline void uart_waittxfifonotfull(uart_dev_t *dev) +{ + int tmp; + for (tmp = 1000 ; tmp > 0 ; tmp--) + { + if (uart_txfifonotfull(dev)) + { + break; + } + } +} +#endif + +/************************************************************************************ + * Name: uart_takesem + ************************************************************************************/ + +static void uart_takesem(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_ptr() == EINTR); + } +} + +/************************************************************************************ + * Name: uart_givesem + ************************************************************************************/ + +static inline void uart_givesem(sem_t *sem) +{ + (void)sem_post(sem); +} + +/************************************************************************************ + * Name: uart_putxmitchar + ************************************************************************************/ + +static void uart_putxmitchar(uart_dev_t *dev, int ch) +{ + int nexthead = dev->xmit.head + 1; + if (nexthead >= dev->xmit.size) + { + nexthead = 0; + } + + for(;;) + { + if (nexthead != dev->xmit.tail) + { + dev->xmit.buffer[dev->xmit.head] = ch; + dev->xmit.head = nexthead; + return; + } + else + { +#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_SERIAL_INTS) + /* Transfer some characters with interrupts disabled */ + + uart_xmitchars(dev); + + /* If we unsuccessful in making room in the buffer. + * then transmit the characters with interrupts + * enabled and wait for result. + */ + + if (nexthead == dev->xmit.tail) + { + /* Still no space */ + + uart_waittxfifonotfull(dev); + } +#else + /* Inform the interrupt level logic that we are waiting */ + + dev->xmitwaiting = TRUE; + + /* Wait for some characters to be sent from the buffer + * with the TX interrupt enabled. When the TX interrupt + * is enabled, uart_xmitchars should execute and remove + * some of the data from the TX buffer. + */ + + uart_enabletxint(dev); + uart_takesem(&dev->xmitsem); + uart_disabletxint(dev); +#endif + } + } +} + +/************************************************************************************ + * Name: uart_irqwrite + ************************************************************************************/ + +static ssize_t uart_irqwrite(uart_dev_t *dev, 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(struct file *filep, const char *buffer, size_t buflen) +{ + struct inode *inode = filep->f_inode; + 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) + { +#if defined(CONFIG_SUPPRESS_INTERRUPTS) || defined(CONFIG_SUPPRESS_SERIAL_INTS) + uart_xmitchars(dev); +#else + uart_enabletxint(dev); +#endif + } + + uart_givesem(&dev->xmit.sem); + return ret; +} + +/************************************************************************************ + * Name: uart_read + ************************************************************************************/ + +static ssize_t uart_read(struct file *filep, char *buffer, size_t buflen) +{ + struct inode *inode = filep->f_inode; + uart_dev_t *dev = inode->i_private; + ssize_t ret = buflen; + + /* 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. + */ + + uart_disablerxint(dev); + while (buflen) + { + if (dev->recv.head != dev->recv.tail) + { + *buffer++ = dev->recv.buffer[dev->recv.tail]; + buflen--; + + if (++(dev->recv.tail) >= dev->recv.size) + { + dev->recv.tail = 0; + } + } + else + { + /* Wait for some characters to be sent from the buffer + * with the TX interrupt disabled. + */ + + dev->recvwaiting = TRUE; + uart_enablerxint(dev); + uart_takesem(&dev->recvsem); + uart_disablerxint(dev); + } + } + + uart_enablerxint(dev); + uart_givesem(&dev->recv.sem); + return ret; +} + +/************************************************************************************ + * Name: uart_ioctl + ************************************************************************************/ + +static int uart_ioctl(struct file *filep, int cmd, unsigned long arg) +{ + struct inode *inode = filep->f_inode; + uart_dev_t *dev = inode->i_private; + + return dev->ops->ioctl(filep, cmd, arg); +} + +/************************************************************************************ + * 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(struct file *filep) +{ + struct inode *inode = filep->f_inode; + 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) + { + usleep(500*1000); + } + + /* And wait for the TX fifo to drain */ + + while (!uart_txfifoempty(dev)) + { + usleep(500*1000); + } + + /* Free the IRQ and disable the UART */ + + flags = irqsave(); /* Disable interrupts */ + up_disable_irq(dev->irq); + irq_detach(dev->irq); + uart_shutdown(dev); + 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(struct file *filep) +{ + struct inode *inode = filep->f_inode; + uart_dev_t *dev = inode->i_private; + 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 */ + + if (++dev->open_count == 1) + { + irqstate_t flags = irqsave(); + + /* If this is the console, then the UART has already + * been initialized. + */ + + if (!dev->isconsole) + { + uart_setup(dev); + } + + /* But, in any event, we do have to configure for + * interrupt driven mode of operation. + */ + + /* Attache and enabled the IRQ */ + +#ifndef CONFIG_SUPPRESS_SERIAL_INTS + ret = irq_attach(dev->irq, dev->ops->handler); + if (ret == OK) +#endif + { + /* Mark the io buffers empty */ + + dev->xmit.head = 0; + dev->xmit.tail = 0; + dev->recv.head = 0; + dev->recv.tail = 0; + + /* Finally, enable interrupts */ + +#ifndef CONFIG_SUPPRESS_SERIAL_INTS + up_enable_irq(dev->irq); +#endif + uart_enablerxint(dev); + } + irqrestore(flags); + } + + uart_givesem(&dev->closesem); + return ret; +} + +/************************************************************************************ + * Public Functions + ************************************************************************************/ + +/************************************************************************************ + * Name: uart_register + * + * Description: + * Register serial console and serial ports. + * + ************************************************************************************/ + +int uart_register(const char *path, 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); + + dbg("Registering %s\n", path); + return register_inode(path, &g_serialops, 0666, dev); +} + +/************************************************************************************ + * Name: uart_xmitchars + * + * Description: + * This function is called from the UART interrupt handler when an interrupt + * is received indicating that there is more space in the transmit FIFO. This + * function will send characters from the tail of the xmit buffer while the driver + * write() logic adds data to the head of the xmit buffer. + * + ************************************************************************************/ + +void uart_xmitchars(uart_dev_t *dev) +{ + /* Send while we still have data & room in the fifo */ + + while (dev->xmit.head != dev->xmit.tail && uart_txfifonotfull(dev)) + { + uart_send(dev, dev->xmit.buffer[dev->xmit.tail]); + + if (++(dev->xmit.tail) >= dev->xmit.size) + { + dev->xmit.tail = 0; + } + + if (dev->xmitwaiting) + { + dev->xmitwaiting = FALSE; + uart_givesem(&dev->xmitsem); + } + } + + /* When all of the characters have been sent from the buffer + * disable the TX interrupt. + */ + + if (dev->xmit.head == dev->xmit.tail) + { + uart_disabletxint(dev); + } +} + +/************************************************************************************ + * Name: uart_receivechars + * + * Description: + * This function is called from the UART interrupt handler when an interrupt + * is received indicating that are bytes available in the receive fifo. This + * function will add chars to head of receive buffer. Driver read() logic will take + * characters from the tail of the buffer. + * + ************************************************************************************/ + +void uart_recvchars(uart_dev_t *dev) +{ + unsigned int status; + int nexthead = dev->recv.head + 1; + + if (nexthead >= dev->recv.size) + { + nexthead = 0; + } + + while (nexthead != dev->recv.tail && uart_rxfifonotempty(dev)) + { + dev->recv.buffer[dev->recv.head] = uart_receive(dev, &status); + + dev->recv.head = nexthead; + if (++nexthead >= dev->recv.size) + { + nexthead = 0; + } + + if (dev->recvwaiting) + { + dev->recvwaiting = FALSE; + uart_givesem(&dev->recvsem); + } + } +} + |