brd = (pChan->xtal/(16*arg)) - 1;	/* calculate baudrate divisor */	    if ((brd < 1) || (brd > 0xFFF))		{		status = EIO;		/* baud rate out of range */		break;		}	    /* disable interrupts during chip access */	    oldlevel = intLock ();	    /* Set baud rate divisor in UART */	    AMBA_UART_REG_WRITE(pChan, L_UBRLCR, brd & 0xFF);	    AMBA_UART_REG_WRITE(pChan, M_UBRLCR, (brd >> 8) & 0xF);	    /*	     * Set word format, enable FIFOs: set 8 bits, 1 stop bit, no parity.	     * This also latches the writes to the two (sub)registers above.	     */	    AMBA_UART_REG_WRITE(pChan, H_UBRLCR,		(UINT8)(WORD_LEN_8 | ONE_STOP | PARITY_NONE | FIFO_ENABLE));	    pChan->baudRate = arg; 	    intUnlock (oldlevel);	    break;	case SIO_BAUD_GET:	    /* Get the baud rate and return OK */	    *(int *)arg = pChan->baudRate;	    break; 	case SIO_MODE_SET:	    /*	     * Set the mode (e.g., to interrupt or polled). Return OK	     * or EIO for an unknown or unsupported mode.	     */	    if ((arg != SIO_MODE_POLL) && (arg != SIO_MODE_INT))		{		status = EIO;		break;		}	   	    oldlevel = intLock ();	    if (arg == SIO_MODE_INT)		{		/* Ensure that only Receive ints are generated. */		AMBA_UART_REG_BIT_CLR(pChan, 				      UARTCON,                                       UART_RTIE | UART_TIE | 				      UART_RIE | UART_MSIE );		AMBA_UART_REG_BIT_SET(pChan, UARTCON, UART_RIE | UART_RTIE);		/* Enable appropriate interrupts. */		intEnable (pChan->levelRx);		/*		 * There is no point in enabling the Tx interrupt, as it		 * will interrupt immediately and be disabled.		 */  		}	    else		{		/* Disable all interrupts for this UART. */ 		intDisable (pChan->levelRx);		if (pChan->levelTx != pChan->levelRx)		    {		    intDisable (pChan->levelTx);		    }		AMBA_UART_REG_BIT_CLR(pChan, 				      UARTCON,                                       UART_RTIE | UART_TIE | 				      UART_RIE | UART_MSIE );		}	    pChan->channelMode = arg;	    intUnlock (oldlevel);	    break;	    	case SIO_MODE_GET:	    /* Get the current mode and return OK */	    *(int *)arg = pChan->channelMode;	    break;	case SIO_AVAIL_MODES_GET:	    /* Get the available modes and return OK */	    *(int *)arg = SIO_MODE_INT | SIO_MODE_POLL;	    break;	case SIO_HW_OPTS_SET:	    /*	     * Optional command to set the hardware options (as defined	     * in sioLib.h).	     * Return OK, or ENOSYS if this command is not implemented.	     * Note: several hardware options are specified at once.	     * This routine should set as many as it can and then return	     * OK. The SIO_HW_OPTS_GET is used to find out which options	     * were actually set.	     */	case SIO_HW_OPTS_GET:	    /*	     * Optional command to get the hardware options (as defined	     * in sioLib.h). Return OK or ENOSYS if this command is not	     * implemented.  Note: if this command is unimplemented, it	     * will be assumed that the driver options are CREAD | CS8	     * (e.g., eight data bits, one stop bit, no parity, ints enabled).	     */	default:	    status = ENOSYS;	}    return status;    }/********************************************************************************* primeCellSioIntTx - handle a transmitter interrupt ** This routine handles write interrupts from the UART.** RETURNS: N/A*/void primeCellSioIntTx     (    AMBA_CHAN *	pChan	/* ptr to AMBA_CHAN describing this channel */    )    {    char outChar;    if ((*pChan->getTxChar) (pChan->getTxArg, &outChar) != ERROR)	/* write char. to Transmit Holding Reg. */	AMBA_UART_REG_WRITE(pChan, UARTDR, outChar);    else	{	/* Disable transmit interrupts. Leave receive interrupts enabled. */	if (pChan->levelTx != pChan->levelRx)	    intDisable (pChan->levelTx);	AMBA_UART_REG_BIT_CLR(pChan, UARTCON, UART_TIE);	}	        }/******************************************************************************* primeCellSioIntRx - handle a receiver interrupt ** This routine handles read interrupts from the UART.** RETURNS: N/A*/void primeCellSioIntRx    (    AMBA_CHAN *	pChan	/* ptr to AMBA_CHAN describing this channel */    )    {    char inchar;    char flags;    BOOL more_data = FALSE;    /* read characters from Receive Holding Reg. */    do	{	/* While RX FIFO isn't empty, we have more data to read */	AMBA_UART_REG_READ(pChan, UARTFLG, flags);	more_data = ( (flags & FLG_URXFE) == 0);	if (more_data)	    {	    /* Read from data register. */	    AMBA_UART_REG_READ(pChan, UARTDR, inchar);	    (*pChan->putRcvChar) (pChan->putRcvArg, inchar);	    }	} while (more_data);    }/******************************************************************************** primeCellSioInt - handle any UART interrupt** This routine handles interrupts from the UART and determines whether* the source is a transmit interrupt or receive/receive-timeout interrupt.** The Prime Cell UART generates a receive interrupt when the RX FIFO is* half-full, and a receive-timeout interrupt after 32 bit-clocks have* elapsed with no incoming data.** RETURNS: N/A*/void primeCellSioInt    (    AMBA_CHAN * pChan   /* ptr to AMBA_CHAN describing this channel */    )    {    char intId;    AMBA_UART_REG_READ(pChan, UARTIIR, intId);    if (intId & UART_TIS)        {	primeCellSioIntTx (pChan);	}    if (intId & UART_RIS || intId & UART_RTIS)	{	primeCellSioIntRx (pChan);	}    AMBA_UART_REG_WRITE(pChan, UARTICR, intId);	/* clear interrupts */    } /********************************************************************************* ambaTxStartup - transmitter startup routine** Enable interrupt so that interrupt-level char output routine will be called.** RETURNS: OK on success, ENOSYS if the device is polled-only, or* EIO on hardware error.*/LOCAL int ambaTxStartup    (    SIO_CHAN *	pSioChan	/* ptr to SIO_CHAN describing this channel */    )    {    AMBA_CHAN * pChan = (AMBA_CHAN *)pSioChan;    if (pChan->channelMode == SIO_MODE_INT)	{	intEnable (pChan->levelTx);	AMBA_UART_REG_BIT_SET(pChan, UARTCON, UART_TIE);	return OK;	}    else	return ENOSYS;    }/******************************************************************************** ambaPollOutput - output a character in polled mode.** RETURNS: OK if a character arrived, EIO on device error, EAGAIN* if the output buffer is full, ENOSYS if the device is interrupt-only.*/LOCAL int ambaPollOutput    (    SIO_CHAN *	pSioChan,	/* ptr to SIO_CHAN describing this channel */    char	outChar 	/* char to output */    )    {    AMBA_CHAN * pChan = (AMBA_CHAN *)pSioChan;    FAST UINT32 pollStatus;    AMBA_UART_REG_READ(pChan, UARTFLG, pollStatus);    /* is the transmitter ready to accept a character? */    if ((pollStatus & FLG_UTXFF) != 0x00)	return EAGAIN;    /* write out the character */    AMBA_UART_REG_WRITE(pChan, UARTDR, outChar);	/* transmit character */    return OK;    }/******************************************************************************** ambaPollInput - poll the device for input.** RETURNS: OK if a character arrived, EIO on device error, EAGAIN* if the input buffer is empty, ENOSYS if the device is interrupt-only.*/LOCAL int ambaPollInput    (    SIO_CHAN *	pSioChan,	/* ptr to SIO_CHAN describing this channel */    char *	thisChar	/* pointer to where to return character */    )    {    AMBA_CHAN * pChan = (AMBA_CHAN *)pSioChan;    FAST UINT32 pollStatus;    AMBA_UART_REG_READ(pChan, UARTFLG, pollStatus);    if ((pollStatus & FLG_URXFE) != 0x00)	return EAGAIN;    /* got a character */    AMBA_UART_REG_READ(pChan, UARTDR, *thisChar);    return OK;    }/******************************************************************************** ambaCallbackInstall - install ISR callbacks to get/put chars.** This routine installs interrupt callbacks for transmitting characters* and receiving characters.** RETURNS: OK on success, or ENOSYS for an unsupported callback type.**/LOCAL int ambaCallbackInstall    (    SIO_CHAN *	pSioChan,	/* ptr to SIO_CHAN describing this channel */    int		callbackType,	/* type of callback */    STATUS	(*callback)(),	/* callback */    void *	callbackArg	/* parameter to callback */		     )    {    AMBA_CHAN * pChan = (AMBA_CHAN *)pSioChan;    switch (callbackType)	{	case SIO_CALLBACK_GET_TX_CHAR:	    pChan->getTxChar	= callback;	    pChan->getTxArg	= callbackArg;	    return OK;	case SIO_CALLBACK_PUT_RCV_CHAR:	    pChan->putRcvChar	= callback;	    pChan->putRcvArg	= callbackArg;	    return OK;	default:	    return ENOSYS;	}    }