/*
 * Print a string to the serial port trying not to disturb
 * any possible real use of the port...
 */
static void pmz_console_write(struct console *con, const char *s, unsigned int count)
{
	struct uart_pmac_port *uap = &pmz_ports[con->index];
	unsigned long flags;
	int i;

	spin_lock_irqsave(&uap->port.lock, flags);

	/* Turn of interrupts and enable the transmitter. */
	write_zsreg(uap, R1, uap->curregs[1] & ~TxINT_ENAB);
	write_zsreg(uap, R5, uap->curregs[5] | TxENABLE | RTS | DTR);

	for (i = 0; i < count; i++) {
		/* Wait for the transmit buffer to empty. */
		while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0)
			udelay(5);
		write_zsdata(uap, s[i]);
		if (s[i] == 10) {
			while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0)
				udelay(5);
			write_zsdata(uap, R13);
		}
	}

	/* Restore the values in the registers. */
	write_zsreg(uap, R1, uap->curregs[1]);
	/* Don't disable the transmitter. */

	spin_unlock_irqrestore(&uap->port.lock, flags);
}

static void z8530_dma_rx(struct z8530_channel *chan)
{
	if(chan->rxdma_on)
	{
		/* Special condition check only */
		u8 status;
	
		read_zsreg(chan, R7);
		read_zsreg(chan, R6);
		
		status=read_zsreg(chan, R1);
	
		if(status&END_FR)
		{
			z8530_rx_done(chan);	/* Fire up the next one */
		}		
		write_zsctrl(chan, ERR_RES);
		write_zsctrl(chan, RES_H_IUS);
	}
	else
	{
		/* DMA is off right now, drain the slow way */
		z8530_rx(chan);
	}	
}

static void pmz_status_handle(struct uart_pmac_port *uap)
{
	unsigned char status;

	status = read_zsreg(uap, R0);
	write_zsreg(uap, R0, RES_EXT_INT);
	zssync(uap);

	if (ZS_IS_OPEN(uap) && ZS_WANTS_MODEM_STATUS(uap)) {
		if (status & SYNC_HUNT)
			uap->port.icount.dsr++;

		/* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
		 * But it does not tell us which bit has changed, we have to keep
		 * track of this ourselves.
		 * The CTS input is inverted for some reason.  -- paulus
		 */
		if ((status ^ uap->prev_status) & DCD)
			uart_handle_dcd_change(&uap->port,
					       (status & DCD));
		if ((status ^ uap->prev_status) & CTS)
			uart_handle_cts_change(&uap->port,
					       !(status & CTS));

		wake_up_interruptible(&uap->port.info->delta_msr_wait);
	}

	if (status & BRK_ABRT)
		uap->flags |= PMACZILOG_FLAG_BREAK;

	uap->prev_status = status;
}

static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id)
{
	struct uart_ip22zilog_port *up = dev_id;

	while (up) {
		struct zilog_channel *channel
			= ZILOG_CHANNEL_FROM_PORT(&up->port);
		unsigned char r3;
		bool push = false;

		spin_lock(&up->port.lock);
		r3 = read_zsreg(channel, R3);

		/* Channel A */
		if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
			writeb(RES_H_IUS, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);

			if (r3 & CHARxIP)
				push = ip22zilog_receive_chars(up, channel);
			if (r3 & CHAEXT)
				ip22zilog_status_handle(up, channel);
			if (r3 & CHATxIP)
				ip22zilog_transmit_chars(up, channel);
		}
		spin_unlock(&up->port.lock);

		if (push)
			tty_flip_buffer_push(&up->port.state->port);

		/* Channel B */
		up = up->next;
		channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
		push = false;

		spin_lock(&up->port.lock);
		if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
			writeb(RES_H_IUS, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);

			if (r3 & CHBRxIP)
				push = ip22zilog_receive_chars(up, channel);
			if (r3 & CHBEXT)
				ip22zilog_status_handle(up, channel);
			if (r3 & CHBTxIP)
				ip22zilog_transmit_chars(up, channel);
		}
		spin_unlock(&up->port.lock);

		if (push)
			tty_flip_buffer_push(&up->port.state->port);

		up = up->next;
	}

	return IRQ_HANDLED;
}

/* Return !=0 iff no more characters in Tx FIFO */
static int asdg_trans_empty(struct async_struct *info)
{
#ifdef DEBUG
  printk("asdg_trans_empty");
#endif

  return read_zsreg((struct SCCHalf *)info->port, R1) & ALL_SNT;
}

static void pmz_console_putchar(struct uart_port *port, int ch)
{
	struct uart_pmac_port *uap = (struct uart_pmac_port *)port;

	/* Wait for the transmit buffer to empty. */
	while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0)
		udelay(5);
	write_zsdata(uap, ch);
}

/*
 * Real startup routine, powers up the hardware and sets up
 * the SCC. Returns a delay in ms where you need to wait before
 * actually using the port, this is typically the internal modem
 * powerup delay. This routine expect the lock to be taken.
 */
static int __pmz_startup(struct uart_pmac_port *uap)
{
	int pwr_delay = 0;

	memset(&uap->curregs, 0, sizeof(uap->curregs));

	/* Power up the SCC & underlying hardware (modem/irda) */
	pwr_delay = pmz_set_scc_power(uap, 1);

	/* Nice buggy HW ... */
	pmz_fix_zero_bug_scc(uap);

	/* Reset the channel */
	uap->curregs[R9] = 0;
	write_zsreg(uap, 9, ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB);
	zssync(uap);
	udelay(10);
	write_zsreg(uap, 9, 0);
	zssync(uap);

	/* Clear the interrupt registers */
	write_zsreg(uap, R1, 0);
	write_zsreg(uap, R0, ERR_RES);
	write_zsreg(uap, R0, ERR_RES);
	write_zsreg(uap, R0, RES_H_IUS);
	write_zsreg(uap, R0, RES_H_IUS);

	/* Setup some valid baud rate */
	uap->curregs[R4] = X16CLK | SB1;
	uap->curregs[R3] = Rx8;
	uap->curregs[R5] = Tx8 | RTS;
	if (!ZS_IS_IRDA(uap))
		uap->curregs[R5] |= DTR;
	uap->curregs[R12] = 0;
	uap->curregs[R13] = 0;
	uap->curregs[R14] = BRENAB;

	/* Clear handshaking, enable BREAK interrupts */
	uap->curregs[R15] = BRKIE;

	/* Master interrupt enable */
	uap->curregs[R9] |= NV | MIE;

	pmz_load_zsregs(uap, uap->curregs);

	/* Enable receiver and transmitter.  */
	write_zsreg(uap, R3, uap->curregs[R3] |= RxENABLE);
	write_zsreg(uap, R5, uap->curregs[R5] |= TxENABLE);

	/* Remember status for DCD/CTS changes */
	uap->prev_status = read_zsreg(uap, R0);


	return pwr_delay;
}

/*
 * Peek the status register, lock not held by caller
 */
static inline u8 pmz_peek_status(struct uart_pmac_port *uap)
{
	unsigned long flags;
	u8 status;
	
	spin_lock_irqsave(&uap->port.lock, flags);
	status = read_zsreg(uap, R0);
	spin_unlock_irqrestore(&uap->port.lock, flags);

	return status;
}

/*
 * FixZeroBug....Works around a bug in the SCC receving channel.
 * Inspired from Darwin code, 15 Sept. 2000  -DanM
 *
 * The following sequence prevents a problem that is seen with O'Hare ASICs
 * (most versions -- also with some Heathrow and Hydra ASICs) where a zero
 * at the input to the receiver becomes 'stuck' and locks up the receiver.
 * This problem can occur as a result of a zero bit at the receiver input
 * coincident with any of the following events:
 *
 *	The SCC is initialized (hardware or software).
 *	A framing error is detected.
 *	The clocking option changes from synchronous or X1 asynchronous
 *		clocking to X16, X32, or X64 asynchronous clocking.
 *	The decoding mode is changed among NRZ, NRZI, FM0, or FM1.
 *
 * This workaround attempts to recover from the lockup condition by placing
 * the SCC in synchronous loopback mode with a fast clock before programming
 * any of the asynchronous modes.
 */
static void pmz_fix_zero_bug_scc(struct uart_pmac_port *uap)
{
	write_zsreg(uap, 9, ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB);
	zssync(uap);
	udelay(10);
	write_zsreg(uap, 9, (ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB) | NV);
	zssync(uap);

	write_zsreg(uap, 4, X1CLK | MONSYNC);
	write_zsreg(uap, 3, Rx8);
	write_zsreg(uap, 5, Tx8 | RTS);
	write_zsreg(uap, 9, NV);	/* Didn't we already do this? */
	write_zsreg(uap, 11, RCBR | TCBR);
	write_zsreg(uap, 12, 0);
	write_zsreg(uap, 13, 0);
	write_zsreg(uap, 14, (LOOPBAK | BRSRC));
	write_zsreg(uap, 14, (LOOPBAK | BRSRC | BRENAB));
	write_zsreg(uap, 3, Rx8 | RxENABLE);
	write_zsreg(uap, 0, RES_EXT_INT);
	write_zsreg(uap, 0, RES_EXT_INT);
	write_zsreg(uap, 0, RES_EXT_INT);	/* to kill some time */

	/* The channel should be OK now, but it is probably receiving
	 * loopback garbage.
	 * Switch to asynchronous mode, disable the receiver,
	 * and discard everything in the receive buffer.
	 */
	write_zsreg(uap, 9, NV);
	write_zsreg(uap, 4, X16CLK | SB_MASK);
	write_zsreg(uap, 3, Rx8);

	while (read_zsreg(uap, 0) & Rx_CH_AV) {
		(void)read_zsreg(uap, 8);
		write_zsreg(uap, 0, RES_EXT_INT);
		write_zsreg(uap, 0, ERR_RES);
	}
}

static unsigned int asdg_get_modem_info(struct async_struct *info)
{
  u_char status=read_zsreg((struct SCCHalf *)info->port, R0);
  
#ifdef DEBUG
  printk("asdg_get_modem_info\n");
#endif

  return(
	 ( (info->MCR & MCR_DTR) ? TIOCM_DTR : 0) |
	 ( (info->MCR & MCR_RTS) ? TIOCM_RTS : 0) |
	 ( (status & DCD) ? TIOCM_CAR : 0) |
	 ( (status & CTS) ? 0 : TIOCM_CTS) |
	 /* TICM_RNG */ 0);
}

static void z8530_dma_status(struct z8530_channel *chan)
{
    u8 status, altered;

    status=read_zsreg(chan, R0);
    altered=chan->status^status;
    
    chan->status=status;


    if(chan->dma_tx)
    {
        if(status&TxEOM)
        {
            unsigned long flags;
    
            flags=claim_dma_lock();
            disable_dma(chan->txdma);
            clear_dma_ff(chan->txdma);    
            chan->txdma_on=0;
            release_dma_lock(flags);
            z8530_tx_done(chan);
        }
    }

    if(altered&chan->dcdcheck)
    {
        if(status&chan->dcdcheck)
        {
            printk(KERN_INFO "%s: DCD raised\n", chan->dev->name);
            write_zsreg(chan, R3, chan->regs[3]|RxENABLE);
            if(chan->netdevice &&
                ((chan->netdevice->type == ARPHRD_HDLC) ||
                (chan->netdevice->type == ARPHRD_PPP)))
                sppp_reopen(chan->netdevice);
        }
        else
        {
            printk(KERN_INFO "%s:DCD lost\n", chan->dev->name);
            write_zsreg(chan, R3, chan->regs[3]&~RxENABLE);
            z8530_flush_fifo(chan);
        }
    }    

    write_zsctrl(chan, RES_EXT_INT);
    write_zsctrl(chan, RES_H_IUS);
}

/* 
 * Get Modem Control bits (only the input ones, the core will
 * or that with a cached value of the control ones)
 * The port lock is held and interrupts are disabled.
 */
static unsigned int pmz_get_mctrl(struct uart_port *port)
{
	struct uart_pmac_port *uap = to_pmz(port);
	unsigned char status;
	unsigned int ret;

	if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
		return 0;

	status = read_zsreg(uap, R0);

	ret = 0;
	if (status & DCD)
		ret |= TIOCM_CAR;
	if (status & SYNC_HUNT)
		ret |= TIOCM_DSR;
	if (!(status & CTS))
		ret |= TIOCM_CTS;

	return ret;
}

/* 
 * Kick the Tx side.
 * The port lock is held and interrupts are disabled.
 */
static void pmz_start_tx(struct uart_port *port)
{
	struct uart_pmac_port *uap = to_pmz(port);
	unsigned char status;

	pmz_debug("pmz: start_tx()\n");

	uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
	uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;

	if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
		return;

	status = read_zsreg(uap, R0);

	/* TX busy?  Just wait for the TX done interrupt.  */
	if (!(status & Tx_BUF_EMP))
		return;

	/* Send the first character to jump-start the TX done
	 * IRQ sending engine.
	 */
	if (port->x_char) {
		write_zsdata(uap, port->x_char);
		zssync(uap);
		port->icount.tx++;
		port->x_char = 0;
	} else {
		struct circ_buf *xmit = &port->info->xmit;

		write_zsdata(uap, xmit->buf[xmit->tail]);
		zssync(uap);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;

		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
			uart_write_wakeup(&uap->port);
	}
	pmz_debug("pmz: start_tx() done.\n");
}

static void __init ip22zilog_init_hw(void)
{
	int i;

	for (i = 0; i < NUM_CHANNELS; i++) {
		struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
		struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
		unsigned long flags;
		int baud, brg;

		spin_lock_irqsave(&up->port.lock, flags);

		if (ZS_IS_CHANNEL_A(up)) {
			write_zsreg(channel, R9, FHWRES);
			ZSDELAY_LONG();
			(void) read_zsreg(channel, R0);
		}

		/* Normal serial TTY. */
		up->parity_mask = 0xff;
		up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
		up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
		up->curregs[R3] = RxENAB | Rx8;
		up->curregs[R5] = TxENAB | Tx8;
		up->curregs[R9] = NV | MIE;
		up->curregs[R10] = NRZ;
		up->curregs[R11] = TCBR | RCBR;
		baud = 9600;
		brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
		up->curregs[R12] = (brg & 0xff);
		up->curregs[R13] = (brg >> 8) & 0xff;
		up->curregs[R14] = BRENAB;
		__load_zsregs(channel, up->curregs);
	        /* set master interrupt enable */
	        write_zsreg(channel, R9, up->curregs[R9]);

		spin_unlock_irqrestore(&up->port.lock, flags);
	}
}

static void ip22zilog_clear_fifo(struct zilog_channel *channel)
{
	int i;

	for (i = 0; i < 32; i++) {
		unsigned char regval;

		regval = readb(&channel->control);
		ZSDELAY();
		if (regval & Rx_CH_AV)
			break;

		regval = read_zsreg(channel, R1);
		readb(&channel->data);
		ZSDELAY();

		if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
			writeb(ERR_RES, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);
		}
	}
}

/*
 * Set the irda codec on the imac to the specified baud rate.
 */
static void pmz_irda_setup(struct uart_pmac_port *uap, unsigned long *baud)
{
	u8 cmdbyte;
	int t, version;

	switch (*baud) {
	/* SIR modes */
	case 2400:
		cmdbyte = 0x53;
		break;
	case 4800:
		cmdbyte = 0x52;
		break;
	case 9600:
		cmdbyte = 0x51;
		break;
	case 19200:
		cmdbyte = 0x50;
		break;
	case 38400:
		cmdbyte = 0x4f;
		break;
	case 57600:
		cmdbyte = 0x4e;
		break;
	case 115200:
		cmdbyte = 0x4d;
		break;
	/* The FIR modes aren't really supported at this point, how
	 * do we select the speed ? via the FCR on KeyLargo ?
	 */
	case 1152000:
		cmdbyte = 0;
		break;
	case 4000000:
		cmdbyte = 0;
		break;
	default: /* 9600 */
		cmdbyte = 0x51;
		*baud = 9600;
		break;
	}

	/* Wait for transmitter to drain */
	t = 10000;
	while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0
	       || (read_zsreg(uap, R1) & ALL_SNT) == 0) {
		if (--t <= 0) {
			dev_err(&uap->dev->ofdev.dev, "transmitter didn't drain\n");
			return;
		}
		udelay(10);
	}

	/* Drain the receiver too */
	t = 100;
	(void)read_zsdata(uap);
	(void)read_zsdata(uap);
	(void)read_zsdata(uap);
	mdelay(10);
	while (read_zsreg(uap, R0) & Rx_CH_AV) {
		read_zsdata(uap);
		mdelay(10);
		if (--t <= 0) {
			dev_err(&uap->dev->ofdev.dev, "receiver didn't drain\n");
			return;
		}
	}

	/* Switch to command mode */
	uap->curregs[R5] |= DTR;
	write_zsreg(uap, R5, uap->curregs[R5]);
	zssync(uap);
       	mdelay(1);

	/* Switch SCC to 19200 */
	pmz_convert_to_zs(uap, CS8, 0, 19200);		
	pmz_load_zsregs(uap, uap->curregs);
       	mdelay(1);

	/* Write get_version command byte */
	write_zsdata(uap, 1);
	t = 5000;
	while ((read_zsreg(uap, R0) & Rx_CH_AV) == 0) {
		if (--t <= 0) {
			dev_err(&uap->dev->ofdev.dev,
				"irda_setup timed out on get_version byte\n");
			goto out;
		}
		udelay(10);
	}
	version = read_zsdata(uap);

	if (version < 4) {
		dev_info(&uap->dev->ofdev.dev, "IrDA: dongle version %d not supported\n",
			 version);
		goto out;
//.........这里部分代码省略.........

static bool ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
						  struct zilog_channel *channel)
{
	unsigned char ch, flag;
	unsigned int r1;
	bool push = up->port.state != NULL;

	for (;;) {
		ch = readb(&channel->control);
		ZSDELAY();
		if (!(ch & Rx_CH_AV))
			break;

		r1 = read_zsreg(channel, R1);
		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
			writeb(ERR_RES, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);
		}

		ch = readb(&channel->data);
		ZSDELAY();

		ch &= up->parity_mask;

		/* Handle the null char got when BREAK is removed.  */
		if (!ch)
			r1 |= up->tty_break;

		/* A real serial line, record the character and status.  */
		flag = TTY_NORMAL;
		up->port.icount.rx++;
		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | Rx_SYS | Rx_BRK)) {
			up->tty_break = 0;

			if (r1 & (Rx_SYS | Rx_BRK)) {
				up->port.icount.brk++;
				if (r1 & Rx_SYS)
					continue;
				r1 &= ~(PAR_ERR | CRC_ERR);
			}
			else if (r1 & PAR_ERR)
				up->port.icount.parity++;
			else if (r1 & CRC_ERR)
				up->port.icount.frame++;
			if (r1 & Rx_OVR)
				up->port.icount.overrun++;
			r1 &= up->port.read_status_mask;
			if (r1 & Rx_BRK)
				flag = TTY_BREAK;
			else if (r1 & PAR_ERR)
				flag = TTY_PARITY;
			else if (r1 & CRC_ERR)
				flag = TTY_FRAME;
		}

		if (uart_handle_sysrq_char(&up->port, ch))
			continue;

		if (push)
			uart_insert_char(&up->port, r1, Rx_OVR, ch, flag);
	}
	return push;
}

/* This function must only be called when the TX is not busy.  The UART
 * port lock must be held and local interrupts disabled.
 */
static void __load_zsregs(struct zilog_channel *channel, unsigned char *regs)
{
	int i;

	/* Let pending transmits finish.  */
	for (i = 0; i < 1000; i++) {
		unsigned char stat = read_zsreg(channel, R1);
		if (stat & ALL_SNT)
			break;
		udelay(100);
	}

	writeb(ERR_RES, &channel->control);
	ZSDELAY();
	ZS_WSYNC(channel);

	ip22zilog_clear_fifo(channel);

	/* Disable all interrupts.  */
	write_zsreg(channel, R1,
		    regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));

	/* Set parity, sync config, stop bits, and clock divisor.  */
	write_zsreg(channel, R4, regs[R4]);

	/* Set misc. TX/RX control bits.  */
	write_zsreg(channel, R10, regs[R10]);

	/* Set TX/RX controls sans the enable bits.  */
	write_zsreg(channel, R3, regs[R3] & ~RxENAB);
	write_zsreg(channel, R5, regs[R5] & ~TxENAB);

	/* Synchronous mode config.  */
	write_zsreg(channel, R6, regs[R6]);
	write_zsreg(channel, R7, regs[R7]);

	/* Don't mess with the interrupt vector (R2, unused by us) and
	 * master interrupt control (R9).  We make sure this is setup
	 * properly at probe time then never touch it again.
	 */

	/* Disable baud generator.  */
	write_zsreg(channel, R14, regs[R14] & ~BRENAB);

	/* Clock mode control.  */
	write_zsreg(channel, R11, regs[R11]);

	/* Lower and upper byte of baud rate generator divisor.  */
	write_zsreg(channel, R12, regs[R12]);
	write_zsreg(channel, R13, regs[R13]);

	/* Now rewrite R14, with BRENAB (if set).  */
	write_zsreg(channel, R14, regs[R14]);

	/* External status interrupt control.  */
	write_zsreg(channel, R15, regs[R15]);

	/* Reset external status interrupts.  */
	write_zsreg(channel, R0, RES_EXT_INT);
	write_zsreg(channel, R0, RES_EXT_INT);

	/* Rewrite R3/R5, this time without enables masked.  */
	write_zsreg(channel, R3, regs[R3]);
	write_zsreg(channel, R5, regs[R5]);

	/* Rewrite R1, this time without IRQ enabled masked.  */
	write_zsreg(channel, R1, regs[R1]);
}

/* Hrm... we register that twice, fixme later.... */
static irqreturn_t pmz_interrupt(int irq, void *dev_id)
{
	struct uart_pmac_port *uap = dev_id;
	struct uart_pmac_port *uap_a;
	struct uart_pmac_port *uap_b;
	int rc = IRQ_NONE;
	struct tty_struct *tty;
	u8 r3;

	uap_a = pmz_get_port_A(uap);
	uap_b = uap_a->mate;
       
       	spin_lock(&uap_a->port.lock);
	r3 = read_zsreg(uap_a, R3);

#ifdef DEBUG_HARD
	pmz_debug("irq, r3: %x\n", r3);
#endif
       	/* Channel A */
	tty = NULL;
       	if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
		write_zsreg(uap_a, R0, RES_H_IUS);
		zssync(uap_a);		
       		if (r3 & CHAEXT)
       			pmz_status_handle(uap_a);
		if (r3 & CHARxIP)
			tty = pmz_receive_chars(uap_a);
       		if (r3 & CHATxIP)
       			pmz_transmit_chars(uap_a);
	        rc = IRQ_HANDLED;
       	}
       	spin_unlock(&uap_a->port.lock);
	if (tty != NULL)
		tty_flip_buffer_push(tty);

	if (uap_b->node == NULL)
		goto out;

       	spin_lock(&uap_b->port.lock);
	tty = NULL;
	if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
		write_zsreg(uap_b, R0, RES_H_IUS);
		zssync(uap_b);
       		if (r3 & CHBEXT)
       			pmz_status_handle(uap_b);
       	       	if (r3 & CHBRxIP)
       			tty = pmz_receive_chars(uap_b);
       		if (r3 & CHBTxIP)
       			pmz_transmit_chars(uap_b);
	       	rc = IRQ_HANDLED;
       	}
       	spin_unlock(&uap_b->port.lock);
	if (tty != NULL)
		tty_flip_buffer_push(tty);

 out:
#ifdef DEBUG_HARD
	pmz_debug("irq done.\n");
#endif
	return rc;
}

static void pmz_transmit_chars(struct uart_pmac_port *uap)
{
	struct circ_buf *xmit;

	if (ZS_IS_ASLEEP(uap))
		return;
	if (ZS_IS_CONS(uap)) {
		unsigned char status = read_zsreg(uap, R0);

		/* TX still busy?  Just wait for the next TX done interrupt.
		 *
		 * It can occur because of how we do serial console writes.  It would
		 * be nice to transmit console writes just like we normally would for
		 * a TTY line. (ie. buffered and TX interrupt driven).  That is not
		 * easy because console writes cannot sleep.  One solution might be
		 * to poll on enough port->xmit space becomming free.  -DaveM
		 */
		if (!(status & Tx_BUF_EMP))
			return;
	}

	uap->flags &= ~PMACZILOG_FLAG_TX_ACTIVE;

	if (ZS_REGS_HELD(uap)) {
		pmz_load_zsregs(uap, uap->curregs);
		uap->flags &= ~PMACZILOG_FLAG_REGS_HELD;
	}

	if (ZS_TX_STOPPED(uap)) {
		uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;
		goto ack_tx_int;
	}

	if (uap->port.x_char) {
		uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
		write_zsdata(uap, uap->port.x_char);
		zssync(uap);
		uap->port.icount.tx++;
		uap->port.x_char = 0;
		return;
	}

	if (uap->port.info == NULL)
		goto ack_tx_int;
	xmit = &uap->port.info->xmit;
	if (uart_circ_empty(xmit)) {
		uart_write_wakeup(&uap->port);
		goto ack_tx_int;
	}
	if (uart_tx_stopped(&uap->port))
		goto ack_tx_int;

	uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
	write_zsdata(uap, xmit->buf[xmit->tail]);
	zssync(uap);

	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
	uap->port.icount.tx++;

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(&uap->port);

	return;

ack_tx_int:
	write_zsreg(uap, R0, RES_Tx_P);
	zssync(uap);
}