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Commit a2237a2d authored by Daeseok Youn's avatar Daeseok Youn Committed by Greg Kroah-Hartman
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staging: dgnc: re-arrange functions for removing



Re-arrange the functions for removing forward declarations in dgnc_cls.c file.

Signed-off-by: default avatarDaeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c23b48e0
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+460 −489
Original line number Diff line number Diff line
@@ -26,56 +26,6 @@
#include "dgnc_cls.h"
#include "dgnc_tty.h"

static inline void cls_parse_isr(struct dgnc_board *brd, uint port);
static inline void cls_clear_break(struct channel_t *ch, int force);
static inline void cls_set_cts_flow_control(struct channel_t *ch);
static inline void cls_set_rts_flow_control(struct channel_t *ch);
static inline void cls_set_ixon_flow_control(struct channel_t *ch);
static inline void cls_set_ixoff_flow_control(struct channel_t *ch);
static inline void cls_set_no_output_flow_control(struct channel_t *ch);
static inline void cls_set_no_input_flow_control(struct channel_t *ch);
static void cls_parse_modem(struct channel_t *ch, unsigned char signals);
static void cls_tasklet(unsigned long data);
static void cls_vpd(struct dgnc_board *brd);
static void cls_uart_init(struct channel_t *ch);
static void cls_uart_off(struct channel_t *ch);
static int cls_drain(struct tty_struct *tty, uint seconds);
static void cls_param(struct tty_struct *tty);
static void cls_assert_modem_signals(struct channel_t *ch);
static void cls_flush_uart_write(struct channel_t *ch);
static void cls_flush_uart_read(struct channel_t *ch);
static void cls_disable_receiver(struct channel_t *ch);
static void cls_enable_receiver(struct channel_t *ch);
static void cls_send_break(struct channel_t *ch, int msecs);
static void cls_send_start_character(struct channel_t *ch);
static void cls_send_stop_character(struct channel_t *ch);
static void cls_copy_data_from_uart_to_queue(struct channel_t *ch);
static void cls_copy_data_from_queue_to_uart(struct channel_t *ch);
static uint cls_get_uart_bytes_left(struct channel_t *ch);
static void cls_send_immediate_char(struct channel_t *ch, unsigned char);
static irqreturn_t cls_intr(int irq, void *voidbrd);

struct board_ops dgnc_cls_ops = {
	.tasklet =			cls_tasklet,
	.intr =				cls_intr,
	.uart_init =			cls_uart_init,
	.uart_off =			cls_uart_off,
	.drain =			cls_drain,
	.param =			cls_param,
	.vpd =				cls_vpd,
	.assert_modem_signals =		cls_assert_modem_signals,
	.flush_uart_write =		cls_flush_uart_write,
	.flush_uart_read =		cls_flush_uart_read,
	.disable_receiver =		cls_disable_receiver,
	.enable_receiver =		cls_enable_receiver,
	.send_break =			cls_send_break,
	.send_start_character =		cls_send_start_character,
	.send_stop_character =		cls_send_stop_character,
	.copy_data_from_queue_to_uart = cls_copy_data_from_queue_to_uart,
	.get_uart_bytes_left =		cls_get_uart_bytes_left,
	.send_immediate_char =		cls_send_immediate_char
};

static inline void cls_set_cts_flow_control(struct channel_t *ch)
{
	unsigned char lcrb = readb(&ch->ch_cls_uart->lcr);
@@ -357,138 +307,418 @@ static inline void cls_clear_break(struct channel_t *ch, int force)
	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

/* Parse the ISR register for the specific port */
static inline void cls_parse_isr(struct dgnc_board *brd, uint port)
static void cls_copy_data_from_uart_to_queue(struct channel_t *ch)
{
	struct channel_t *ch;
	unsigned char isr = 0;
	int qleft = 0;
	unsigned char linestatus = 0;
	unsigned char error_mask = 0;
	ushort head;
	ushort tail;
	unsigned long flags;

	/*
	 * No need to verify board pointer, it was already
	 * verified in the interrupt routine.
	 */

	if (port >= brd->nasync)
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	ch = brd->channels[port];
	if (ch->magic != DGNC_CHANNEL_MAGIC)
		return;
	spin_lock_irqsave(&ch->ch_lock, flags);

	/* cache head and tail of queue */
	head = ch->ch_r_head;
	tail = ch->ch_r_tail;

	/* Store how much space we have left in the queue */
	qleft = tail - head - 1;
	if (qleft < 0)
		qleft += RQUEUEMASK + 1;

	/*
	 * Create a mask to determine whether we should
	 * insert the character (if any) into our queue.
	 */
	if (ch->ch_c_iflag & IGNBRK)
		error_mask |= UART_LSR_BI;

	/* Here we try to figure out what caused the interrupt to happen */
	while (1) {
		isr = readb(&ch->ch_cls_uart->isr_fcr);
		linestatus = readb(&ch->ch_cls_uart->lsr);

		/* Bail if no pending interrupt on port */
		if (isr & UART_IIR_NO_INT)
		if (!(linestatus & (UART_LSR_DR)))
			break;

		/* Receive Interrupt pending */
		if (isr & (UART_IIR_RDI | UART_IIR_RDI_TIMEOUT)) {
			/* Read data from uart -> queue */
			brd->intr_rx++;
			ch->ch_intr_rx++;
			cls_copy_data_from_uart_to_queue(ch);
			dgnc_check_queue_flow_control(ch);
		}

		/* Transmit Hold register empty pending */
		if (isr & UART_IIR_THRI) {
			/* Transfer data (if any) from Write Queue -> UART. */
			spin_lock_irqsave(&ch->ch_lock, flags);
			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
			brd->intr_tx++;
			ch->ch_intr_tx++;
			spin_unlock_irqrestore(&ch->ch_lock, flags);
			cls_copy_data_from_queue_to_uart(ch);
		/*
		 * Discard character if we are ignoring the error mask.
		*/
		if (linestatus & error_mask)  {
			linestatus = 0;
			readb(&ch->ch_cls_uart->txrx);
			continue;
		}

		/* CTS/RTS change of state */
		if (isr & UART_IIR_CTSRTS) {
			brd->intr_modem++;
			ch->ch_intr_modem++;
		/*
			 * Don't need to do anything, the cls_parse_modem
			 * below will grab the updated modem signals.
		 * If our queue is full, we have no choice but to drop some
		 * data. The assumption is that HWFLOW or SWFLOW should have
		 * stopped things way way before we got to this point.
		 *
		 * I decided that I wanted to ditch the oldest data first,
		 * I hope thats okay with everyone? Yes? Good.
		 */
		while (qleft < 1) {
			tail = (tail + 1) & RQUEUEMASK;
			ch->ch_r_tail = tail;
			ch->ch_err_overrun++;
			qleft++;
		}

		/* Parse any modem signal changes */
		cls_parse_modem(ch, readb(&ch->ch_cls_uart->msr));
	}
		ch->ch_equeue[head] = linestatus & (UART_LSR_BI | UART_LSR_PE
								 | UART_LSR_FE);
		ch->ch_rqueue[head] = readb(&ch->ch_cls_uart->txrx);

		qleft--;

		if (ch->ch_equeue[head] & UART_LSR_PE)
			ch->ch_err_parity++;
		if (ch->ch_equeue[head] & UART_LSR_BI)
			ch->ch_err_break++;
		if (ch->ch_equeue[head] & UART_LSR_FE)
			ch->ch_err_frame++;

		/* Add to, and flip head if needed */
		head = (head + 1) & RQUEUEMASK;
		ch->ch_rxcount++;
	}

	/*
 * cls_param()
 * Send any/all changes to the line to the UART.
	 * Write new final heads to channel structure.
	 */
static void cls_param(struct tty_struct *tty)
	ch->ch_r_head = head & RQUEUEMASK;
	ch->ch_e_head = head & EQUEUEMASK;

	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

/* Make the UART raise any of the output signals we want up */
static void cls_assert_modem_signals(struct channel_t *ch)
{
	unsigned char lcr = 0;
	unsigned char uart_lcr = 0;
	unsigned char ier = 0;
	unsigned char uart_ier = 0;
	uint baud = 9600;
	int quot = 0;
	struct dgnc_board *bd;
	struct channel_t *ch;
	struct un_t   *un;
	unsigned char out;

	if (!tty || tty->magic != TTY_MAGIC)
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	un = (struct un_t *)tty->driver_data;
	if (!un || un->magic != DGNC_UNIT_MAGIC)
		return;
	out = ch->ch_mostat;

	if (ch->ch_flags & CH_LOOPBACK)
		out |= UART_MCR_LOOP;

	writeb(out, &ch->ch_cls_uart->mcr);

	/* Give time for the UART to actually drop the signals */
	udelay(10);
}

static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
{
	ushort head;
	ushort tail;
	int n;
	int qlen;
	uint len_written = 0;
	unsigned long flags;

	ch = un->un_ch;
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	bd = ch->ch_bd;
	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
		return;
	spin_lock_irqsave(&ch->ch_lock, flags);

	/*
	 * If baud rate is zero, flush queues, and set mval to drop DTR.
	 */
	if ((ch->ch_c_cflag & (CBAUD)) == 0) {
		ch->ch_r_head = 0;
		ch->ch_r_tail = 0;
		ch->ch_e_head = 0;
		ch->ch_e_tail = 0;
		ch->ch_w_head = 0;
		ch->ch_w_tail = 0;
	/* No data to write to the UART */
	if (ch->ch_w_tail == ch->ch_w_head)
		goto exit_unlock;

		cls_flush_uart_write(ch);
		cls_flush_uart_read(ch);
	/* If port is "stopped", don't send any data to the UART */
	if ((ch->ch_flags & CH_FORCED_STOP) ||
	    (ch->ch_flags & CH_BREAK_SENDING))
		goto exit_unlock;

		/* The baudrate is B0 so all modem lines are to be dropped. */
		ch->ch_flags |= (CH_BAUD0);
		ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
		cls_assert_modem_signals(ch);
		ch->ch_old_baud = 0;
		return;
	} else if (ch->ch_custom_speed) {
		baud = ch->ch_custom_speed;
		/* Handle transition from B0 */
		if (ch->ch_flags & CH_BAUD0) {
			ch->ch_flags &= ~(CH_BAUD0);
	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
		goto exit_unlock;

	n = 32;

	/* cache head and tail of queue */
	head = ch->ch_w_head & WQUEUEMASK;
	tail = ch->ch_w_tail & WQUEUEMASK;
	qlen = (head - tail) & WQUEUEMASK;

	/* Find minimum of the FIFO space, versus queue length */
	n = min(n, qlen);

	while (n > 0) {
		/*
			 * Bring back up RTS and DTR...
			 * Also handle RTS or DTR toggle if set.
		 * If RTS Toggle mode is on, turn on RTS now if not already set,
		 * and make sure we get an event when the data transfer has
		 * completed.
		 */
			if (!(ch->ch_digi.digi_flags & DIGI_RTS_TOGGLE))
		if (ch->ch_digi.digi_flags & DIGI_RTS_TOGGLE) {
			if (!(ch->ch_mostat & UART_MCR_RTS)) {
				ch->ch_mostat |= (UART_MCR_RTS);
			if (!(ch->ch_digi.digi_flags & DIGI_DTR_TOGGLE))
				cls_assert_modem_signals(ch);
			}
			ch->ch_tun.un_flags |= (UN_EMPTY);
		}

		/*
		 * If DTR Toggle mode is on, turn on DTR now if not already set,
		 * and make sure we get an event when the data transfer has
		 * completed.
		 */
		if (ch->ch_digi.digi_flags & DIGI_DTR_TOGGLE) {
			if (!(ch->ch_mostat & UART_MCR_DTR)) {
				ch->ch_mostat |= (UART_MCR_DTR);
				cls_assert_modem_signals(ch);
			}
			ch->ch_tun.un_flags |= (UN_EMPTY);
		}
		writeb(ch->ch_wqueue[ch->ch_w_tail], &ch->ch_cls_uart->txrx);
		ch->ch_w_tail++;
		ch->ch_w_tail &= WQUEUEMASK;
		ch->ch_txcount++;
		len_written++;
		n--;
	}

	} else {
		int iindex = 0;
		int jindex = 0;
	if (len_written > 0)
		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);

exit_unlock:
	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

static void cls_parse_modem(struct channel_t *ch, unsigned char signals)
{
	unsigned char msignals = signals;
	unsigned long flags;

	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	/*
	 * Do altpin switching. Altpin switches DCD and DSR.
	 * This prolly breaks DSRPACE, so we should be more clever here.
	 */
	spin_lock_irqsave(&ch->ch_lock, flags);
	if (ch->ch_digi.digi_flags & DIGI_ALTPIN) {
		unsigned char mswap = signals;

		if (mswap & UART_MSR_DDCD) {
			msignals &= ~UART_MSR_DDCD;
			msignals |= UART_MSR_DDSR;
		}
		if (mswap & UART_MSR_DDSR) {
			msignals &= ~UART_MSR_DDSR;
			msignals |= UART_MSR_DDCD;
		}
		if (mswap & UART_MSR_DCD) {
			msignals &= ~UART_MSR_DCD;
			msignals |= UART_MSR_DSR;
		}
		if (mswap & UART_MSR_DSR) {
			msignals &= ~UART_MSR_DSR;
			msignals |= UART_MSR_DCD;
		}
	}
	spin_unlock_irqrestore(&ch->ch_lock, flags);

	/*
	 * Scrub off lower bits. They signify delta's, which I don't
	 * care about
	 */
	signals &= 0xf0;

	spin_lock_irqsave(&ch->ch_lock, flags);
	if (msignals & UART_MSR_DCD)
		ch->ch_mistat |= UART_MSR_DCD;
	else
		ch->ch_mistat &= ~UART_MSR_DCD;

	if (msignals & UART_MSR_DSR)
		ch->ch_mistat |= UART_MSR_DSR;
	else
		ch->ch_mistat &= ~UART_MSR_DSR;

	if (msignals & UART_MSR_RI)
		ch->ch_mistat |= UART_MSR_RI;
	else
		ch->ch_mistat &= ~UART_MSR_RI;

	if (msignals & UART_MSR_CTS)
		ch->ch_mistat |= UART_MSR_CTS;
	else
		ch->ch_mistat &= ~UART_MSR_CTS;
	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

/* Parse the ISR register for the specific port */
static inline void cls_parse_isr(struct dgnc_board *brd, uint port)
{
	struct channel_t *ch;
	unsigned char isr = 0;
	unsigned long flags;

	/*
	 * No need to verify board pointer, it was already
	 * verified in the interrupt routine.
	 */

	if (port >= brd->nasync)
		return;

	ch = brd->channels[port];
	if (ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	/* Here we try to figure out what caused the interrupt to happen */
	while (1) {
		isr = readb(&ch->ch_cls_uart->isr_fcr);

		/* Bail if no pending interrupt on port */
		if (isr & UART_IIR_NO_INT)
			break;

		/* Receive Interrupt pending */
		if (isr & (UART_IIR_RDI | UART_IIR_RDI_TIMEOUT)) {
			/* Read data from uart -> queue */
			brd->intr_rx++;
			ch->ch_intr_rx++;
			cls_copy_data_from_uart_to_queue(ch);
			dgnc_check_queue_flow_control(ch);
		}

		/* Transmit Hold register empty pending */
		if (isr & UART_IIR_THRI) {
			/* Transfer data (if any) from Write Queue -> UART. */
			spin_lock_irqsave(&ch->ch_lock, flags);
			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
			brd->intr_tx++;
			ch->ch_intr_tx++;
			spin_unlock_irqrestore(&ch->ch_lock, flags);
			cls_copy_data_from_queue_to_uart(ch);
		}

		/* CTS/RTS change of state */
		if (isr & UART_IIR_CTSRTS) {
			brd->intr_modem++;
			ch->ch_intr_modem++;
			/*
			 * Don't need to do anything, the cls_parse_modem
			 * below will grab the updated modem signals.
			 */
		}

		/* Parse any modem signal changes */
		cls_parse_modem(ch, readb(&ch->ch_cls_uart->msr));
	}
}

/* Channel lock MUST be held before calling this function! */
static void cls_flush_uart_write(struct channel_t *ch)
{
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT),
	       &ch->ch_cls_uart->isr_fcr);
	usleep_range(10, 20);

	ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
}

/* Channel lock MUST be held before calling this function! */
static void cls_flush_uart_read(struct channel_t *ch)
{
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	/*
	 * For complete POSIX compatibility, we should be purging the
	 * read FIFO in the UART here.
	 *
	 * However, clearing the read FIFO (UART_FCR_CLEAR_RCVR) also
	 * incorrectly flushes write data as well as just basically trashing the
	 * FIFO.
	 *
	 * Presumably, this is a bug in this UART.
	 */

	udelay(10);
}

/*
 * cls_param()
 * Send any/all changes to the line to the UART.
 */
static void cls_param(struct tty_struct *tty)
{
	unsigned char lcr = 0;
	unsigned char uart_lcr = 0;
	unsigned char ier = 0;
	unsigned char uart_ier = 0;
	uint baud = 9600;
	int quot = 0;
	struct dgnc_board *bd;
	struct channel_t *ch;
	struct un_t   *un;

	if (!tty || tty->magic != TTY_MAGIC)
		return;

	un = (struct un_t *)tty->driver_data;
	if (!un || un->magic != DGNC_UNIT_MAGIC)
		return;

	ch = un->un_ch;
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	bd = ch->ch_bd;
	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
		return;

	/*
	 * If baud rate is zero, flush queues, and set mval to drop DTR.
	 */
	if ((ch->ch_c_cflag & (CBAUD)) == 0) {
		ch->ch_r_head = 0;
		ch->ch_r_tail = 0;
		ch->ch_e_head = 0;
		ch->ch_e_tail = 0;
		ch->ch_w_head = 0;
		ch->ch_w_tail = 0;

		cls_flush_uart_write(ch);
		cls_flush_uart_read(ch);

		/* The baudrate is B0 so all modem lines are to be dropped. */
		ch->ch_flags |= (CH_BAUD0);
		ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
		cls_assert_modem_signals(ch);
		ch->ch_old_baud = 0;
		return;
	} else if (ch->ch_custom_speed) {
		baud = ch->ch_custom_speed;
		/* Handle transition from B0 */
		if (ch->ch_flags & CH_BAUD0) {
			ch->ch_flags &= ~(CH_BAUD0);

			/*
			 * Bring back up RTS and DTR...
			 * Also handle RTS or DTR toggle if set.
			 */
			if (!(ch->ch_digi.digi_flags & DIGI_RTS_TOGGLE))
				ch->ch_mostat |= (UART_MCR_RTS);
			if (!(ch->ch_digi.digi_flags & DIGI_DTR_TOGGLE))
				ch->ch_mostat |= (UART_MCR_DTR);
		}

	} else {
		int iindex = 0;
		int jindex = 0;

		ulong bauds[4][16] = {
			{ /* slowbaud */
@@ -804,109 +1034,22 @@ static void cls_enable_receiver(struct channel_t *ch)
	writeb(tmp, &ch->ch_cls_uart->ier);
}

static void cls_copy_data_from_uart_to_queue(struct channel_t *ch)
/*
 * This function basically goes to sleep for secs, or until
 * it gets signalled that the port has fully drained.
 */
static int cls_drain(struct tty_struct *tty, uint seconds)
{
	int qleft = 0;
	unsigned char linestatus = 0;
	unsigned char error_mask = 0;
	ushort head;
	ushort tail;
	unsigned long flags;
	struct channel_t *ch;
	struct un_t *un;

	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;
	if (!tty || tty->magic != TTY_MAGIC)
		return -ENXIO;

	spin_lock_irqsave(&ch->ch_lock, flags);

	/* cache head and tail of queue */
	head = ch->ch_r_head;
	tail = ch->ch_r_tail;

	/* Store how much space we have left in the queue */
	qleft = tail - head - 1;
	if (qleft < 0)
		qleft += RQUEUEMASK + 1;

	/*
	 * Create a mask to determine whether we should
	 * insert the character (if any) into our queue.
	 */
	if (ch->ch_c_iflag & IGNBRK)
		error_mask |= UART_LSR_BI;

	while (1) {
		linestatus = readb(&ch->ch_cls_uart->lsr);

		if (!(linestatus & (UART_LSR_DR)))
			break;

		/*
		 * Discard character if we are ignoring the error mask.
		*/
		if (linestatus & error_mask)  {
			linestatus = 0;
			readb(&ch->ch_cls_uart->txrx);
			continue;
		}

		/*
		 * If our queue is full, we have no choice but to drop some
		 * data. The assumption is that HWFLOW or SWFLOW should have
		 * stopped things way way before we got to this point.
		 *
		 * I decided that I wanted to ditch the oldest data first,
		 * I hope thats okay with everyone? Yes? Good.
		 */
		while (qleft < 1) {
			tail = (tail + 1) & RQUEUEMASK;
			ch->ch_r_tail = tail;
			ch->ch_err_overrun++;
			qleft++;
		}

		ch->ch_equeue[head] = linestatus & (UART_LSR_BI | UART_LSR_PE
								 | UART_LSR_FE);
		ch->ch_rqueue[head] = readb(&ch->ch_cls_uart->txrx);

		qleft--;

		if (ch->ch_equeue[head] & UART_LSR_PE)
			ch->ch_err_parity++;
		if (ch->ch_equeue[head] & UART_LSR_BI)
			ch->ch_err_break++;
		if (ch->ch_equeue[head] & UART_LSR_FE)
			ch->ch_err_frame++;

		/* Add to, and flip head if needed */
		head = (head + 1) & RQUEUEMASK;
		ch->ch_rxcount++;
	}

	/*
	 * Write new final heads to channel structure.
	 */
	ch->ch_r_head = head & RQUEUEMASK;
	ch->ch_e_head = head & EQUEUEMASK;

	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

/*
 * This function basically goes to sleep for secs, or until
 * it gets signalled that the port has fully drained.
 */
static int cls_drain(struct tty_struct *tty, uint seconds)
{
	unsigned long flags;
	struct channel_t *ch;
	struct un_t *un;

	if (!tty || tty->magic != TTY_MAGIC)
		return -ENXIO;

	un = (struct un_t *)tty->driver_data;
	if (!un || un->magic != DGNC_UNIT_MAGIC)
		return -ENXIO;
	un = (struct un_t *)tty->driver_data;
	if (!un || un->magic != DGNC_UNIT_MAGIC)
		return -ENXIO;

	ch = un->un_ch;
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
@@ -926,199 +1069,6 @@ static int cls_drain(struct tty_struct *tty, uint seconds)
					 ((un->un_flags & UN_EMPTY) == 0));
}

/* Channel lock MUST be held before calling this function! */
static void cls_flush_uart_write(struct channel_t *ch)
{
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT),
	       &ch->ch_cls_uart->isr_fcr);
	usleep_range(10, 20);

	ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
}

/* Channel lock MUST be held before calling this function! */
static void cls_flush_uart_read(struct channel_t *ch)
{
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	/*
	 * For complete POSIX compatibility, we should be purging the
	 * read FIFO in the UART here.
	 *
	 * However, clearing the read FIFO (UART_FCR_CLEAR_RCVR) also
	 * incorrectly flushes write data as well as just basically trashing the
	 * FIFO.
	 *
	 * Presumably, this is a bug in this UART.
	 */

	udelay(10);
}

static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
{
	ushort head;
	ushort tail;
	int n;
	int qlen;
	uint len_written = 0;
	unsigned long flags;

	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	spin_lock_irqsave(&ch->ch_lock, flags);

	/* No data to write to the UART */
	if (ch->ch_w_tail == ch->ch_w_head)
		goto exit_unlock;

	/* If port is "stopped", don't send any data to the UART */
	if ((ch->ch_flags & CH_FORCED_STOP) ||
	    (ch->ch_flags & CH_BREAK_SENDING))
		goto exit_unlock;

	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
		goto exit_unlock;

	n = 32;

	/* cache head and tail of queue */
	head = ch->ch_w_head & WQUEUEMASK;
	tail = ch->ch_w_tail & WQUEUEMASK;
	qlen = (head - tail) & WQUEUEMASK;

	/* Find minimum of the FIFO space, versus queue length */
	n = min(n, qlen);

	while (n > 0) {
		/*
		 * If RTS Toggle mode is on, turn on RTS now if not already set,
		 * and make sure we get an event when the data transfer has
		 * completed.
		 */
		if (ch->ch_digi.digi_flags & DIGI_RTS_TOGGLE) {
			if (!(ch->ch_mostat & UART_MCR_RTS)) {
				ch->ch_mostat |= (UART_MCR_RTS);
				cls_assert_modem_signals(ch);
			}
			ch->ch_tun.un_flags |= (UN_EMPTY);
		}

		/*
		 * If DTR Toggle mode is on, turn on DTR now if not already set,
		 * and make sure we get an event when the data transfer has
		 * completed.
		 */
		if (ch->ch_digi.digi_flags & DIGI_DTR_TOGGLE) {
			if (!(ch->ch_mostat & UART_MCR_DTR)) {
				ch->ch_mostat |= (UART_MCR_DTR);
				cls_assert_modem_signals(ch);
			}
			ch->ch_tun.un_flags |= (UN_EMPTY);
		}
		writeb(ch->ch_wqueue[ch->ch_w_tail], &ch->ch_cls_uart->txrx);
		ch->ch_w_tail++;
		ch->ch_w_tail &= WQUEUEMASK;
		ch->ch_txcount++;
		len_written++;
		n--;
	}

	if (len_written > 0)
		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);

exit_unlock:
	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

static void cls_parse_modem(struct channel_t *ch, unsigned char signals)
{
	unsigned char msignals = signals;
	unsigned long flags;

	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	/*
	 * Do altpin switching. Altpin switches DCD and DSR.
	 * This prolly breaks DSRPACE, so we should be more clever here.
	 */
	spin_lock_irqsave(&ch->ch_lock, flags);
	if (ch->ch_digi.digi_flags & DIGI_ALTPIN) {
		unsigned char mswap = signals;

		if (mswap & UART_MSR_DDCD) {
			msignals &= ~UART_MSR_DDCD;
			msignals |= UART_MSR_DDSR;
		}
		if (mswap & UART_MSR_DDSR) {
			msignals &= ~UART_MSR_DDSR;
			msignals |= UART_MSR_DDCD;
		}
		if (mswap & UART_MSR_DCD) {
			msignals &= ~UART_MSR_DCD;
			msignals |= UART_MSR_DSR;
		}
		if (mswap & UART_MSR_DSR) {
			msignals &= ~UART_MSR_DSR;
			msignals |= UART_MSR_DCD;
		}
	}
	spin_unlock_irqrestore(&ch->ch_lock, flags);

	/*
	 * Scrub off lower bits. They signify delta's, which I don't
	 * care about
	 */
	signals &= 0xf0;

	spin_lock_irqsave(&ch->ch_lock, flags);
	if (msignals & UART_MSR_DCD)
		ch->ch_mistat |= UART_MSR_DCD;
	else
		ch->ch_mistat &= ~UART_MSR_DCD;

	if (msignals & UART_MSR_DSR)
		ch->ch_mistat |= UART_MSR_DSR;
	else
		ch->ch_mistat &= ~UART_MSR_DSR;

	if (msignals & UART_MSR_RI)
		ch->ch_mistat |= UART_MSR_RI;
	else
		ch->ch_mistat &= ~UART_MSR_RI;

	if (msignals & UART_MSR_CTS)
		ch->ch_mistat |= UART_MSR_CTS;
	else
		ch->ch_mistat &= ~UART_MSR_CTS;
	spin_unlock_irqrestore(&ch->ch_lock, flags);
}

/* Make the UART raise any of the output signals we want up */
static void cls_assert_modem_signals(struct channel_t *ch)
{
	unsigned char out;

	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
		return;

	out = ch->ch_mostat;

	if (ch->ch_flags & CH_LOOPBACK)
		out |= UART_MCR_LOOP;

	writeb(out, &ch->ch_cls_uart->mcr);

	/* Give time for the UART to actually drop the signals */
	udelay(10);
}

static void cls_send_start_character(struct channel_t *ch)
{
	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
@@ -1298,3 +1248,24 @@ static void cls_vpd(struct dgnc_board *brd)

	iounmap(re_map_vpdbase);
}

struct board_ops dgnc_cls_ops = {
	.tasklet =			cls_tasklet,
	.intr =				cls_intr,
	.uart_init =			cls_uart_init,
	.uart_off =			cls_uart_off,
	.drain =			cls_drain,
	.param =			cls_param,
	.vpd =				cls_vpd,
	.assert_modem_signals =		cls_assert_modem_signals,
	.flush_uart_write =		cls_flush_uart_write,
	.flush_uart_read =		cls_flush_uart_read,
	.disable_receiver =		cls_disable_receiver,
	.enable_receiver =		cls_enable_receiver,
	.send_break =			cls_send_break,
	.send_start_character =		cls_send_start_character,
	.send_stop_character =		cls_send_stop_character,
	.copy_data_from_queue_to_uart = cls_copy_data_from_queue_to_uart,
	.get_uart_bytes_left =		cls_get_uart_bytes_left,
	.send_immediate_char =		cls_send_immediate_char
};