c6x1x_edma_mcasp.c

在DSP（DEC6713）上实现了音频的采样与播放！

    /* Open theEDMA Channel */
#if (CHIP_DM642)
    edmaChanEvent = eventIds[port->devId][chan->mode]; 
#else
    edmaChanEvent = EDMA_map(eventIds[port->devId][chan->mode], 
            params->edmaChan); 
#endif
    chan->xferPram = EDMA_open(edmaChanEvent, EDMA_OPEN_RESET);

    if (chan->xferPram == EDMA_HINV) {
        chanCleanUp(chan, FREETABLEEX);
        return (IOM_EALLOC);
    }

    /* Program the data EDMA job with the TCC */
    EDMA_FSETA(&params->edmaCfgPtr->opt, OPT, TCC, chan->tcc);

#if ENABLELOOPINTR
    EDMA_intHook(loopTcc, &isrLoop);
    EDMA_FSETA(&loopEdmaCfg.opt, OPT, TCINT, EDMA_OPT_TCINT_YES);
    EDMA_FSETA(&loopEdmaCfg.opt, OPT, TCC, loopTcc);
#endif

    /* Program the link PaRAMs with the config struct */
    for (i=0; i < MAXLINKCNT; i++) {
        EDMA_config(chan->pramTbl[i], params->edmaCfgPtr);
    }

    /* Program the Loop EDMA job with its config struct */
    EDMA_config(chan->loophEdma, &loopEdmaCfg);

    /*
     * Link the Loop EDMA job to itself to make it run
     * continuously when there is no data to transmit.
     */
    EDMA_link(chan->loophEdma, chan->loophEdma);

    /* Configure the EDMA channel to start with the Loop EDMA job */
    EDMA_config(chan->xferPram, &loopEdmaCfg);
    EDMA_link(chan->xferPram, chan->loophEdma);

    /* Transfer complete is edge triggered, so clear before enabling */
    EDMA_intClear(chan->tcc);
    EDMA_intEnable(chan->tcc);

#if ENABLELOOPINTR
    EDMA_intClear(loopTcc);
    EDMA_intEnable(loopTcc);
#endif

    /* Enable the EDMA interrupt */
    IRQ_enable(IRQ_EVT_EDMAINT);

    EDMA_enableChannel(chan->xferPram);

    /* Start the McASP */
    if (chan->mode == INPUT) {
        old = ATM_setu(&(port->chanCreated), TRUE);
        
        /* 
         * clock generator is divided from high frequency clock, so start high
         * freq clock generator first 
         */
        if (port->enableHclkg == C6X1X_EDMA_MCASP_RCV) {
            MCASP_enableHclk(port->hMcasp, MCASP_RCV); 
            while(!MCASP_FGETH(port->hMcasp, GBLCTL, RHCLKRST));
        }
        else if ((port->enableHclkg == C6X1X_EDMA_MCASP_RCVXMT) && (old)) {
            MCASP_enableHclk(port->hMcasp, MCASP_RCVXMT); 
            while(!(MCASP_FGETH(port->hMcasp, GBLCTL, RHCLKRST) & 
                    MCASP_FGETH(port->hMcasp, GBLCTL, XHCLKRST)));
        }

        if (port->enableClkg == C6X1X_EDMA_MCASP_RCV) {
            MCASP_enableClk(port->hMcasp, MCASP_RCV); 
            while(!MCASP_FGETH(port->hMcasp, GBLCTL, RCLKRST)); 
        } 
        else if ((port->enableClkg == C6X1X_EDMA_MCASP_RCVXMT) && (old)) {
            MCASP_enableClk(port->hMcasp, MCASP_RCVXMT); 
            while(!( MCASP_FGETH(port->hMcasp, GBLCTL, RCLKRST) & 
                MCASP_FGETH(port->hMcasp, GBLCTL, XCLKRST)));
        } 

#if STARTSERIALIZERSYNC
        if (old) {
            MCASP_enableSers(port->hMcasp, MCASP_RCVXMT);
            while (!(MCASP_FGETH(port->hMcasp, GBLCTL, RSRCLR) &
                    MCASP_FGETH(port->hMcasp, GBLCTL, XSRCLR)));

            while (MCASP_xdata(port->hMcasp));

            MCASP_enableSm(port->hMcasp, MCASP_RCVXMT);
            while (!(MCASP_FGETH(port->hMcasp, GBLCTL, RSMRST) &
                    MCASP_FGETH(port->hMcasp, GBLCTL, XSMRST)));     
        }
#else
        MCASP_enableSers(port->hMcasp, MCASP_RCV);
        while (!MCASP_FGETH(port->hMcasp, GBLCTL, RSRCLR));

        MCASP_enableSm(port->hMcasp, MCASP_RCV);
        while (!MCASP_FGETH(port->hMcasp, GBLCTL, RSMRST));     
#endif

        if (port->enableFsyncg == C6X1X_EDMA_MCASP_RCV) {
              MCASP_enableFsync(port->hMcasp, MCASP_RCV);
              while(!MCASP_FGETH(port->hMcasp, GBLCTL, RFRST));    
        }
        else if ((port->enableFsyncg == C6X1X_EDMA_MCASP_RCVXMT) && (old)) {
            MCASP_enableFsync(port->hMcasp, MCASP_RCVXMT);
            while(!(MCASP_FGETH(port->hMcasp, GBLCTL, RFRST) & 
                    MCASP_FGETH(port->hMcasp, GBLCTL, XFRST)) );       
        } 
    }
    else {
        old = ATM_setu(&(port->chanCreated), TRUE);

        /* 
         * clock generator is divided from high frequency clock, so start high
         * freq clock generator first 
         */
        if (port->enableHclkg == C6X1X_EDMA_MCASP_XMT) {
            MCASP_enableHclk(port->hMcasp, MCASP_XMT); 
            while(!MCASP_FGETH(port->hMcasp, GBLCTL, XHCLKRST));

        }
        else if ((port->enableHclkg  == C6X1X_EDMA_MCASP_RCVXMT) && (old)) {
            MCASP_enableHclk(port->hMcasp, MCASP_RCVXMT); 
            while(!( MCASP_FGETH(port->hMcasp, GBLCTL, RHCLKRST) & 
                    MCASP_FGETH(port->hMcasp, GBLCTL, XHCLKRST)));
        }

        if (port->enableClkg == C6X1X_EDMA_MCASP_XMT) {
            MCASP_enableClk(port->hMcasp, MCASP_XMT); 
            while(!MCASP_FGETH(port->hMcasp, GBLCTL, XCLKRST));
        }
        else if ((port->enableClkg == C6X1X_EDMA_MCASP_RCVXMT) && (old)) {
            MCASP_enableClk(port->hMcasp, MCASP_RCVXMT); 
            while(!( MCASP_FGETH(port->hMcasp, GBLCTL, RCLKRST) & 
                    MCASP_FGETH(port->hMcasp, GBLCTL, XCLKRST)));
        }


#if STARTSERIALIZERSYNC
        if (old) {
            MCASP_enableSers(port->hMcasp, MCASP_RCVXMT);
            while (!(MCASP_FGETH(port->hMcasp, GBLCTL, XSRCLR) &
                    MCASP_FGETH(port->hMcasp, GBLCTL, RSRCLR)));

            while (MCASP_xdata(port->hMcasp));

            MCASP_enableSm(port->hMcasp, MCASP_RCVXMT);
            while (!(MCASP_FGETH(port->hMcasp, GBLCTL, XSMRST) &
                    MCASP_FGETH(port->hMcasp, GBLCTL, RSMRST)));     
        }
#else
        MCASP_enableSers(port->hMcasp, MCASP_XMT);
        while (!(MCASP_FGETH(port->hMcasp, GBLCTL, XSRCLR)));

        while (MCASP_xdata(port->hMcasp));

        MCASP_enableSm(port->hMcasp, MCASP_XMT);
        while (!(MCASP_FGETH(port->hMcasp, GBLCTL, XSMRST)));     
#endif

        if (port->enableFsyncg == C6X1X_EDMA_MCASP_XMT) {
            MCASP_enableFsync(port->hMcasp, MCASP_XMT);
            while(!MCASP_FGETH(port->hMcasp,GBLCTL, XFRST));       
        }
        else if ((port->enableFsyncg == C6X1X_EDMA_MCASP_RCVXMT) && (old)) {
            MCASP_enableFsync(port->hMcasp, MCASP_RCVXMT);
            while(!(MCASP_FGETH(port->hMcasp,GBLCTL, RFRST) & 
                    MCASP_FGETH(port->hMcasp,GBLCTL, XFRST)) );       
        } 
    } 

    /* enable McASP event interrupt if registered */
    /* Clear CKFAIL error before enable interrupt */
    if (chan->mode == INPUT) { 
        if (port->evtCallback != NULL) {
            if (port->evtMask & C6X1X_EDMA_MCASP_EVT_RCKFAIL) { 
                MCASP_FSETSH(port->hMcasp, RINTCTL, RCKFAIL, DISABLE);
                while (MCASP_FGETH(port->hMcasp, RSTAT, RCKFAIL)) {
                    MCASP_FSETSH(port->hMcasp, RSTAT, RCKFAIL, YES);
                }
                MCASP_FSETSH(port->hMcasp, RINTCTL, RCKFAIL, ENABLE);
            }

            IRQ_enable(MCASP_getRcvEventId(port->hMcasp));
        }
    } 
    else { 
        if (port->evtCallback != NULL) { 
            if (port->evtMask & C6X1X_EDMA_MCASP_EVT_XCKFAIL) { 
                MCASP_FSETSH(port->hMcasp, XINTCTL, XCKFAIL, DISABLE);
                while (MCASP_FGETH(port->hMcasp, XSTAT, XCKFAIL)) {
                    MCASP_FSETSH(port->hMcasp, XSTAT, XCKFAIL, YES);
                }
                MCASP_FSETSH(port->hMcasp, XINTCTL, XCKFAIL, ENABLE);
            }

            IRQ_enable(MCASP_getXmtEventId(port->hMcasp));
        }
    }
    
    *chanp = (Ptr) chan;
    return (IOM_COMPLETED);
}

/*
 * ======== mdDeleteChan ========
 * This function frees a channel and all it's associated resources.
 */
static Int mdDeleteChan(Ptr chanp)
{
    ChanHandle chan = (ChanHandle) chanp;
    PortHandle port = chan->port;

    /* Clean up the channel resources */
    chanCleanUp(chan, DELCHAN);

    /*
     * Reset the McASP transmitter or receiver. If the channel is
     * recreated, mdCreateChan() will reenable the transmitter/receiver
     * and by pulling it out of reset it will also restart the EDMA channel.
     */
    if (chan->mode == INPUT) {
        MCASP_resetRcv(port->hMcasp);
    }
    else {
        MCASP_resetXmt(port->hMcasp);
    }

    return (IOM_COMPLETED);
}

/*
 * ======== mdSubmitChan ========
 * This function transmits a buffer to or from the McASP using the EDMA.
 */
static Int mdSubmitChan(Ptr chanp, IOM_Packet *packet)
{
    ChanHandle chan = (ChanHandle) chanp;
    PortHandle port = chan->port;
    Uns imask;

    /* No packets can be submitted while abort or flush is active */
    if (chan->flushPacket || chan->abortPacket) {
        return (IOM_EBADIO);
    }

    /*
     * Check to see if an abort command has been issued. Note that
     * flushing the input channel is handled the same as abort.
     */
    if ((packet->cmd == IOM_FLUSH && chan->mode == INPUT) ||
        packet->cmd == IOM_ABORT) {

        /* Disable interrupts to protect submitCount */
        imask = HWI_disable();

        /* Store the abort packet for the ISR to check */
        if (chan->submitCount > 0) {
            chan->abortPacket = packet;

            /*
             * Disable the EDMA channel while linking the currently
             * executing job while linking it with the Loop job to make
             * sure the currently executing job doesn't complete before
             * the link is complete.
             */
            EDMA_disableChannel(chan->xferPram);
            EDMA_link(chan->xferPram, chan->loophEdma);
            EDMA_enableChannel(chan->xferPram);
        }

        /* Reenable interrupts */
        HWI_restore(imask);

        if (chan->abortPacket) {
            return(IOM_PENDING);
        }

        /* If there were no buffers in the channel, return synchronously */
        packet->status = IOM_COMPLETED;

        return (IOM_COMPLETED);
    }

    /* Check to see if the submitted packet is an output flush packet */
    if (packet->cmd == IOM_FLUSH && chan->mode == OUTPUT) {
        /* Disable interrupts to protect submitCount */
        imask = HWI_disable();

        /* Store the flush packet for the ISR to check */
        if (chan->submitCount > 0) {
            chan->flushPacket = packet;
        }

        /* Reenable interrupts */
        HWI_restore(imask);

        if (chan->flushPacket) {
            return(IOM_PENDING);
        }

        /* If there were no buffers in the channel, return synchronously */
        packet->status = IOM_COMPLETED;

        return (IOM_COMPLETED);
    }

    if (packet->cmd != IOM_READ && packet->cmd != IOM_WRITE) {
        /* Unsupported command passed */
        return (IOM_ENOTIMPL);
    }

    /* maintain cache coherency */
    if (chan->mode == INPUT) {
        /* CACHE uses words, and packet->size is in nmaus (bytes on c6x) */
        if (port->cacheCalls) {
            CACHE_clean(CACHE_L2, packet->addr, packet->size >> 2);
        }
    }
    else {
        /* CACHE uses words, and packet->size is in nmaus (bytes on c6x) */
        if (port->cacheCalls) {
            CACHE_flush(CACHE_L2, packet->addr, packet->size >> 2);
        }
    }

    /* Disable interrupts to protect submitCount */
    imask = HWI_disable();
    /*
     * If there is no space available for the new packet, put it on a
     * queue to be linked in when space is available. Otherwise link it in.
     */
    if (chan->submitCount >= MAXLINKCNT) {
        QUE_enqueue(&chan->packetQueue, packet);
    }
    else {
        linkPacket(chan, packet);
    }

    chan->submitCount++;

    HWI_restore(imask);

    return (IOM_PENDING);
}

/*
 * ======== mdUnBindDev ========
 * This function frees a port and all it's associated resources.
 */
static Int mdUnBindDev(Ptr devp)
{
    PortHandle port = (PortHandle) devp;

    port->inUse = FALSE;

    /* Close the McASP */
    MCASP_close(port->hMcasp);

    return (IOM_COMPLETED);
}

/*
 * ======== C6X1X_EDMA_MCASP_init ========
 * This function initializes the driver's data structures.
 */
#pragma CODE_SECTION(C6X1X_EDMA_MCASP_init, ".text:init");
Void C6X1X_EDMA_MCASP_init()
{
    PortHandle port;
    ChanHandle chan;
    Int i, j;
    /* Make sure the initialization only happens once for thid driver */
    static Bool curInit = FALSE;

    if (curInit) {
        return;
    }
    curInit = TRUE;

    for (i=0; i<NUMPORTS; i++) {
        port = &ports[i];

        port->inUse = FALSE;

        for (j=0; j<NUMCHANS; j++) {
            chan = &port->chans[j];

            chan->inUse = FALSE;
        }
    }
}