usartavr.c

含有完整TCP/IP PPP协议的嵌入式操作系统

/*
 * Copyright (C) 2001-2003 by egnite Software GmbH. All rights reserved.
 *
 * 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 of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH 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 EGNITE
 * SOFTWARE GMBH 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.
 *
 * For additional information see http://www.ethernut.de/
 *
 * The 9-bit communication had been contributed by Brett Abbott,
 * Digital Telemetry Limited.
 *
 * Dave Smart contributed the synchronous mode support.
 */

/*
 * $Log: usartavr.c,v $
 * Revision 1.2  2005/10/07 22:05:00  hwmaier
 * Using __AVR_ENHANCED__ macro instead of __AVR_ATmega128__ to support also AT90CAN128 MCU
 *
 * Revision 1.1  2005/07/26 18:02:40  haraldkipp
 * Moved from dev.
 *
 * Revision 1.10  2005/07/22 08:07:07  freckle
 * added experimental improvements to usart driver. see ChangeLog for details
 *
 * Revision 1.9  2005/02/21 12:38:00  phblum
 * Removed tabs and added semicolons after NUTTRACER macros
 *
 * Revision 1.8  2005/01/24 22:34:46  freckle
 * Added new tracer by Phlipp Blum <[e-mail]>
 *
 * Revision 1.6  2005/01/21 16:49:46  freckle
 * Seperated calls to NutEventPostAsync between Threads and IRQs
 *
 * Revision 1.5  2004/11/12 08:25:51  drsung
 * Bugfix in AvrUsartTxEmpty. Thanks to Grzegorz Plonski and Matthias Ringwald.
 *
 * Revision 1.4  2004/05/26 09:04:17  drsung
 * Bugfix in AvrUsartTxStart. Now the correct port and pin are used for half duplex mode...again...
 * Thanks to Przemyslaw Rudy.
 *
 * Revision 1.3  2004/05/16 14:09:06  drsung
 * Applied bugfixes for half duplex mode an XON/XOFF handling. Thanks to Damian Slee.
 *
 * Revision 1.2  2004/04/07 12:58:52  haraldkipp
 * Bugfix for half duplex mode
 *
 * Revision 1.1  2003/12/15 19:25:33  haraldkipp
 * New USART driver added
 *
 */

#include <sys/atom.h>
#include <sys/event.h>
#include <sys/timer.h>

#include <dev/irqreg.h>

#include <dev/usartavr.h>

#ifdef NUTTRACER
#include <sys/tracer.h>
#endif

/*!
 * \addtogroup xgUsartAvr
 */
/*@{*/

/* \brief ASCII code for software flow control, starts transmitter. */
#define ASCII_XON   0x11
/* \brief ASCII code for software flow control, stops transmitter. */
#define ASCII_XOFF  0x13

/* \brief XON transmit pending flag. */
#define XON_PENDING     0x10
/* \brief XOFF transmit pending flag. */
#define XOFF_PENDING    0x20
/* \brief XOFF sent flag. */
#define XOFF_SENT       0x40
/* \brief XOFF received flag. */
#define XOFF_RCVD       0x80


/*!
 * \brief Receiver error flags.
 */
static ureg_t rx_errors;

/*!
 * \brief Enables software flow control if not equal zero.
 */
static ureg_t flow_control;

/*!
 * \brief Transmit address frame, if not zero.
 */
static ureg_t tx_aframe;

#ifdef UART_HDX_BIT
	/* define in cfg/modem.h */
	#ifdef UART_HDX_FLIP_BIT	/* same as RTS toggle by Windows NT driver */
		#define UART_HDX_TX		cbi
		#define UART_HDX_RX		sbi
	#else						/* previous usage by Ethernut */
		#define UART_HDX_TX		sbi
		#define UART_HDX_RX		cbi
	#endif
#endif


#ifdef UART_HDX_BIT
/*!
 * \brief Enables half duplex control if not equal zero.
 *
 * This variable exists only if the hardware configuration defines a
 * port bit to switch between receive and transmit mode.
 */
static ureg_t hdx_control;
#endif

#ifdef UART_RTS_BIT
/*!
 * \brief Enables RTS control if not equal zero.
 *
 * This variable exists only if the hardware configuration defines a
 * port bit to control the RTS signal.
 */
static ureg_t rts_control;
#endif

#ifdef UART_CTS_BIT
/*!
 * \brief Enables CTS sense if not equal zero.
 *
 * This variable exists only if the hardware configuration defines a
 * port bit to sense the CTS signal.
 */
static ureg_t cts_sense;
#endif

#ifdef UART_CTS_BIT
/*!
 * \brief USARTn CTS sense interrupt handler.
 *
 * This interrupt routine is called when the CTS line level is low.
 * Typical line drivers negate the signal, thus driving our port
 * low when CTS is active.
 *
 * This routine exists only if the hardware configuration defines a
 * port bit to sense the CTS signal.
 */
static void AvrUsartCts(void *arg)
{
    /* Enable transmit interrupt. */
    sbi(UCSRnB, UDRIE);
    /* Disable CTS sense interrupt. */
    cbi(EIMSK, UART_CTS_BIT);
}
#endif

#ifdef UART_HDX_BIT
/*
 * \brief USARTn transmit complete interrupt handler.
 *
 * Used with half duplex communication to switch from tranmit to receive
 * mode after the last character has been transmitted.
 *
 * This routine exists only if the hardware configuration defines a
 * port bit to switch between receive and transmit mode.
 *
 * \param arg Pointer to the transmitter ring buffer.
 */
static void AvrUsartTxComplete(void *arg)
{
    register RINGBUF *rbf = (RINGBUF *) arg;

    /*
     * Check if half duplex mode has been enabled and if all characters
     * had been sent out.
     */
    if (hdx_control && rbf->rbf_cnt == 0) {
        /* Switch to receiver mode. */
        UART_HDX_RX(UART_HDX_PORT, UART_HDX_BIT);
    }
}
#endif

/*
 * \brief USARTn transmit data register empty interrupt handler.
 *
 * \param arg Pointer to the transmitter ring buffer.
 */
#ifdef USE_USART

SIGNAL( SIG_UART_DATA ) {
    register RINGBUF *rbf = &dcb_usart.dcb_tx_rbf;

#else

static void AvrUsartTxEmpty(void *arg) {
    register RINGBUF *rbf = (RINGBUF *) arg;

#endif

    register u_char *cp = rbf->rbf_tail;


#ifdef NUTTRACER
    TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_ENTER,TRACE_INT_UART_TXEMPTY);
#endif

#ifndef UART_NO_SW_FLOWCONTROL

    /*
     * Process pending software flow controls first.
     */
    if (flow_control & (XON_PENDING | XOFF_PENDING)) {
        if (flow_control & XON_PENDING) {
            outb(UDRn, ASCII_XOFF);
            flow_control |= XOFF_SENT;
        } else {
            outb(UDRn, ASCII_XON);
            flow_control &= ~XOFF_SENT;
        }
        flow_control &= ~(XON_PENDING | XOFF_PENDING);
#ifdef NUTTRACER
        TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_TXEMPTY);
#endif
        return;
    }

    if (flow_control & XOFF_RCVD) {
        /*
         * If XOFF has been received, we disable the transmit interrupts
         * and return without sending anything.
         */
        cbi(UCSRnB, UDRIE);
#ifdef NUTTRACER
        TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_TXEMPTY);
#endif
        return;
	}
#endif /* UART_NO_SW_FLOWCONTROL */

    if (rbf->rbf_cnt) {

#ifdef UART_CTS_BIT
        /*
         * If CTS has been disabled, we disable the transmit interrupts
         * and return without sending anything.
         */
        if (cts_sense && bit_is_set(UART_CTS_PIN, UART_CTS_BIT)) {
            cbi(UCSRnB, UDRIE);
            sbi(EIMSK, UART_CTS_BIT);
#ifdef NUTTRACER
            TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_TXEMPTY);
#endif
            return;
        }
#endif
        rbf->rbf_cnt--;

        /*
         * The data sheet doesn't exactly tell us, if this bit is retained
         * or cleared after the character has been sent out. So we do it
         * the save way.
         */
        if (tx_aframe) {
            sbi(UCSRnB, TXB8);
        } else {
            cbi(UCSRnB, TXB8);
        }

        /*
         * Start transmission of the next character.
         */
        outb(UDRn, *cp);

        /*
         * Wrap around the buffer pointer if we reached its end.
         */
        if (++cp == rbf->rbf_last) {
            cp = rbf->rbf_start;
        }
        rbf->rbf_tail = cp;
        if (rbf->rbf_cnt == rbf->rbf_lwm) {
            NutEventPostFromIrq(&rbf->rbf_que);
        }
    }

    /*
     * Nothing left to transmit, disable interrupt.
     */
    else {
        cbi(UCSRnB, UDRIE);
        rbf->rbf_cnt = 0;
        NutEventPostFromIrq(&rbf->rbf_que);
    }
#ifdef NUTTRACER
    TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_TXEMPTY);
#endif
}


/*
 * \brief USARTn receive complete interrupt handler.
 *
 *
 * \param arg Pointer to the receiver ring buffer.
 */

#ifdef USE_USART
SIGNAL( SIG_UART_RECV ){
    register RINGBUF *rbf = &dcb_usart.dcb_rx_rbf;

#else

static void AvrUsartRxComplete(void *arg) {
    register RINGBUF *rbf = (RINGBUF *) arg;

#endif

    register size_t cnt;
    register u_char ch;


#ifdef NUTTRACER
    TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_ENTER,TRACE_INT_UART_RXCOMPL);
#endif

#ifdef UART_READMULTIBYTE
    register u_char postEvent = 0;
    do {
#endif

        /*
         * We read the received character as early as possible to avoid overflows
         * caused by interrupt latency. However, reading the error flags must come
         * first, because reading the ATmega128 data register clears the status.
         */
        rx_errors |= inb(UCSRnA);
        ch = inb(UDRn);

#ifndef UART_NO_SW_FLOWCONTROL
        /*
         * Handle software handshake. We have to do this before checking the
         * buffer, because flow control must work in write-only mode, where
         * there is no receive buffer.
         */
        if (flow_control) {
            /* XOFF character disables transmit interrupts. */
            if (ch == ASCII_XOFF) {
                cbi(UCSRnB, UDRIE);
                flow_control |= XOFF_RCVD;
#ifdef NUTTRACER
                TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_RXCOMPL);
#endif
                return;
            }
            /* XON enables transmit interrupts. */
            else if (ch == ASCII_XON) {
                sbi(UCSRnB, UDRIE);
                flow_control &= ~XOFF_RCVD;
#ifdef NUTTRACER
                TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_RXCOMPL);
#endif
                return;
            }
        }
#endif

        /*
         * Check buffer overflow.
         */
        cnt = rbf->rbf_cnt;
        if (cnt >= rbf->rbf_siz) {
            rx_errors |= _BV(DOR);
#ifdef NUTTRACER
            TRACE_ADD_ITEM(TRACE_TAG_INTERRUPT_EXIT,TRACE_INT_UART_RXCOMPL);
#endif
            return;
        }

        /* Wake up waiting threads if this is the first byte in the buffer. */
        if (cnt++ == 0){
#ifdef UART_READMULTIBYTE
            // we do this later, to get the other bytes in time..
            postEvent = 1;
#else
            NutEventPostFromIrq(&rbf->rbf_que);
#endif
        }

#ifndef UART_NO_SW_FLOWCONTROL

        /*
         * Check the high watermark for software handshake. If the number of
         * buffered bytes is above this mark, then send XOFF.
         */
        else if (flow_control) {
            if(cnt >= rbf->rbf_hwm) {
                if((flow_control & XOFF_SENT) == 0) {
                    if (inb(UCSRnA) & _BV(UDRE)) {
                        outb(UDRn, ASCII_XOFF);
                        flow_control |= XOFF_SENT;
                        flow_control &= ~XOFF_PENDING;
                    } else {
                        flow_control |= XOFF_PENDING;
                    }
                }
            }
        }
#endif


#ifdef UART_RTS_BIT
        /*
         * Check the high watermark for hardware handshake. If the number of
         * buffered bytes is above this mark, then disable RTS.
         */
        else if (rts_control && cnt >= rbf->rbf_hwm) {
            sbi(UART_RTS_PORT, UART_RTS_BIT);
        }
#endif