Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 973 insertions, 0 deletions

diff --git a/drivers/tty/serial/jsm/jsm_cls.c b/drivers/tty/serial/jsm/jsm_cls.c
new file mode 100644
index 000000000..c061a7b7b
--- /dev/null
+++ b/drivers/tty/serial/jsm/jsm_cls.c
@@ -0,0 +1,973 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2003 Digi International (www.digi.com)
+ *	Scott H Kilau <Scott_Kilau at digi dot com>
+ *
+ *	NOTE TO LINUX KERNEL HACKERS:  DO NOT REFORMAT THIS CODE!
+ *
+ *	This is shared code between Digi's CVS archive and the
+ *	Linux Kernel sources.
+ *	Changing the source just for reformatting needlessly breaks
+ *	our CVS diff history.
+ *
+ *	Send any bug fixes/changes to:  Eng.Linux at digi dot com.
+ *	Thank you.
+ *
+ */
+
+#include <linux/delay.h>	/* For udelay */
+#include <linux/io.h>		/* For read[bwl]/write[bwl] */
+#include <linux/serial.h>	/* For struct async_serial */
+#include <linux/serial_reg.h>	/* For the various UART offsets */
+#include <linux/pci.h>
+#include <linux/tty.h>
+
+#include "jsm.h"	/* Driver main header file */
+
+static struct {
+	unsigned int rate;
+	unsigned int cflag;
+} baud_rates[] = {
+	{ 921600, B921600 },
+	{ 460800, B460800 },
+	{ 230400, B230400 },
+	{ 115200, B115200 },
+	{  57600, B57600  },
+	{  38400, B38400  },
+	{  19200, B19200  },
+	{   9600, B9600   },
+	{   4800, B4800   },
+	{   2400, B2400   },
+	{   1200, B1200   },
+	{    600, B600    },
+	{    300, B300    },
+	{    200, B200    },
+	{    150, B150    },
+	{    134, B134    },
+	{    110, B110    },
+	{     75, B75     },
+	{     50, B50     },
+};
+
+static void cls_set_cts_flow_control(struct jsm_channel *ch)
+{
+	u8 lcrb = readb(&ch->ch_cls_uart->lcr);
+	u8 ier = readb(&ch->ch_cls_uart->ier);
+	u8 isr_fcr = 0;
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn on CTS flow control, turn off IXON flow control */
+	isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_CTSDSR);
+	isr_fcr &= ~(UART_EXAR654_EFR_IXON);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/*
+	 * Enable interrupts for CTS flow, turn off interrupts for
+	 * received XOFF chars
+	 */
+	ier |= (UART_EXAR654_IER_CTSDSR);
+	ier &= ~(UART_EXAR654_IER_XOFF);
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	/* Set the usual FIFO values */
+	writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_56 |
+		UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
+		&ch->ch_cls_uart->isr_fcr);
+
+	ch->ch_t_tlevel = 16;
+}
+
+static void cls_set_ixon_flow_control(struct jsm_channel *ch)
+{
+	u8 lcrb = readb(&ch->ch_cls_uart->lcr);
+	u8 ier = readb(&ch->ch_cls_uart->ier);
+	u8 isr_fcr = 0;
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn on IXON flow control, turn off CTS flow control */
+	isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_IXON);
+	isr_fcr &= ~(UART_EXAR654_EFR_CTSDSR);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Now set our current start/stop chars while in enhanced mode */
+	writeb(ch->ch_startc, &ch->ch_cls_uart->mcr);
+	writeb(0, &ch->ch_cls_uart->lsr);
+	writeb(ch->ch_stopc, &ch->ch_cls_uart->msr);
+	writeb(0, &ch->ch_cls_uart->spr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/*
+	 * Disable interrupts for CTS flow, turn on interrupts for
+	 * received XOFF chars
+	 */
+	ier &= ~(UART_EXAR654_IER_CTSDSR);
+	ier |= (UART_EXAR654_IER_XOFF);
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	/* Set the usual FIFO values */
+	writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
+		UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
+		&ch->ch_cls_uart->isr_fcr);
+}
+
+static void cls_set_no_output_flow_control(struct jsm_channel *ch)
+{
+	u8 lcrb = readb(&ch->ch_cls_uart->lcr);
+	u8 ier = readb(&ch->ch_cls_uart->ier);
+	u8 isr_fcr = 0;
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn off IXON flow control, turn off CTS flow control */
+	isr_fcr |= (UART_EXAR654_EFR_ECB);
+	isr_fcr &= ~(UART_EXAR654_EFR_CTSDSR | UART_EXAR654_EFR_IXON);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/*
+	 * Disable interrupts for CTS flow, turn off interrupts for
+	 * received XOFF chars
+	 */
+	ier &= ~(UART_EXAR654_IER_CTSDSR);
+	ier &= ~(UART_EXAR654_IER_XOFF);
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	/* Set the usual FIFO values */
+	writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
+		UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
+		&ch->ch_cls_uart->isr_fcr);
+
+	ch->ch_r_watermark = 0;
+	ch->ch_t_tlevel = 16;
+	ch->ch_r_tlevel = 16;
+}
+
+static void cls_set_rts_flow_control(struct jsm_channel *ch)
+{
+	u8 lcrb = readb(&ch->ch_cls_uart->lcr);
+	u8 ier = readb(&ch->ch_cls_uart->ier);
+	u8 isr_fcr = 0;
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn on RTS flow control, turn off IXOFF flow control */
+	isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_RTSDTR);
+	isr_fcr &= ~(UART_EXAR654_EFR_IXOFF);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/* Enable interrupts for RTS flow */
+	ier |= (UART_EXAR654_IER_RTSDTR);
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	/* Set the usual FIFO values */
+	writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_56 |
+		UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
+		&ch->ch_cls_uart->isr_fcr);
+
+	ch->ch_r_watermark = 4;
+	ch->ch_r_tlevel = 8;
+}
+
+static void cls_set_ixoff_flow_control(struct jsm_channel *ch)
+{
+	u8 lcrb = readb(&ch->ch_cls_uart->lcr);
+	u8 ier = readb(&ch->ch_cls_uart->ier);
+	u8 isr_fcr = 0;
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn on IXOFF flow control, turn off RTS flow control */
+	isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_IXOFF);
+	isr_fcr &= ~(UART_EXAR654_EFR_RTSDTR);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Now set our current start/stop chars while in enhanced mode */
+	writeb(ch->ch_startc, &ch->ch_cls_uart->mcr);
+	writeb(0, &ch->ch_cls_uart->lsr);
+	writeb(ch->ch_stopc, &ch->ch_cls_uart->msr);
+	writeb(0, &ch->ch_cls_uart->spr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/* Disable interrupts for RTS flow */
+	ier &= ~(UART_EXAR654_IER_RTSDTR);
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	/* Set the usual FIFO values */
+	writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
+		UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
+		&ch->ch_cls_uart->isr_fcr);
+}
+
+static void cls_set_no_input_flow_control(struct jsm_channel *ch)
+{
+	u8 lcrb = readb(&ch->ch_cls_uart->lcr);
+	u8 ier = readb(&ch->ch_cls_uart->ier);
+	u8 isr_fcr = 0;
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn off IXOFF flow control, turn off RTS flow control */
+	isr_fcr |= (UART_EXAR654_EFR_ECB);
+	isr_fcr &= ~(UART_EXAR654_EFR_RTSDTR | UART_EXAR654_EFR_IXOFF);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/* Disable interrupts for RTS flow */
+	ier &= ~(UART_EXAR654_IER_RTSDTR);
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	/* Set the usual FIFO values */
+	writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
+		UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
+		&ch->ch_cls_uart->isr_fcr);
+
+	ch->ch_t_tlevel = 16;
+	ch->ch_r_tlevel = 16;
+}
+
+/*
+ * cls_clear_break.
+ * Determines whether its time to shut off break condition.
+ *
+ * No locks are assumed to be held when calling this function.
+ * channel lock is held and released in this function.
+ */
+static void cls_clear_break(struct jsm_channel *ch)
+{
+	unsigned long lock_flags;
+
+	spin_lock_irqsave(&ch->ch_lock, lock_flags);
+
+	/* Turn break off, and unset some variables */
+	if (ch->ch_flags & CH_BREAK_SENDING) {
+		u8 temp = readb(&ch->ch_cls_uart->lcr);
+
+		writeb((temp & ~UART_LCR_SBC), &ch->ch_cls_uart->lcr);
+
+		ch->ch_flags &= ~(CH_BREAK_SENDING);
+		jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
+			"clear break Finishing UART_LCR_SBC! finished: %lx\n",
+			jiffies);
+	}
+	spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
+}
+
+static void cls_disable_receiver(struct jsm_channel *ch)
+{
+	u8 tmp = readb(&ch->ch_cls_uart->ier);
+
+	tmp &= ~(UART_IER_RDI);
+	writeb(tmp, &ch->ch_cls_uart->ier);
+}
+
+static void cls_enable_receiver(struct jsm_channel *ch)
+{
+	u8 tmp = readb(&ch->ch_cls_uart->ier);
+
+	tmp |= (UART_IER_RDI);
+	writeb(tmp, &ch->ch_cls_uart->ier);
+}
+
+/* Make the UART raise any of the output signals we want up */
+static void cls_assert_modem_signals(struct jsm_channel *ch)
+{
+	if (!ch)
+		return;
+
+	writeb(ch->ch_mostat, &ch->ch_cls_uart->mcr);
+}
+
+static void cls_copy_data_from_uart_to_queue(struct jsm_channel *ch)
+{
+	int qleft = 0;
+	u8 linestatus = 0;
+	u8 error_mask = 0;
+	u16 head;
+	u16 tail;
+	unsigned long flags;
+
+	if (!ch)
+		return;
+
+	spin_lock_irqsave(&ch->ch_lock, flags);
+
+	/* cache head and tail of queue */
+	head = ch->ch_r_head & RQUEUEMASK;
+	tail = ch->ch_r_tail & RQUEUEMASK;
+
+	/* Get our cached LSR */
+	linestatus = ch->ch_cached_lsr;
+	ch->ch_cached_lsr = 0;
+
+	/* 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) {
+		/*
+		 * Grab the linestatus register, we need to
+		 * check to see if there is any data to read
+		 */
+		linestatus = readb(&ch->ch_cls_uart->lsr);
+
+		/* Break out if there is no data to fetch */
+		if (!(linestatus & UART_LSR_DR))
+			break;
+
+		/*
+		 * Discard character if we are ignoring the error mask
+		 * which in this case is the break signal.
+		 */
+		if (linestatus & error_mask)  {
+			u8 discard;
+
+			linestatus = 0;
+			discard = 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);
+}
+
+static void cls_copy_data_from_queue_to_uart(struct jsm_channel *ch)
+{
+	u16 tail;
+	int n;
+	int qlen;
+	u32 len_written = 0;
+	struct circ_buf *circ;
+
+	if (!ch)
+		return;
+
+	circ = &ch->uart_port.state->xmit;
+
+	/* No data to write to the UART */
+	if (uart_circ_empty(circ))
+		return;
+
+	/* If port is "stopped", don't send any data to the UART */
+	if ((ch->ch_flags & CH_STOP) || (ch->ch_flags & CH_BREAK_SENDING))
+		return;
+
+	/* We have to do it this way, because of the EXAR TXFIFO count bug. */
+	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
+		return;
+
+	n = 32;
+
+	/* cache tail of queue */
+	tail = circ->tail & (UART_XMIT_SIZE - 1);
+	qlen = uart_circ_chars_pending(circ);
+
+	/* Find minimum of the FIFO space, versus queue length */
+	n = min(n, qlen);
+
+	while (n > 0) {
+		writeb(circ->buf[tail], &ch->ch_cls_uart->txrx);
+		tail = (tail + 1) & (UART_XMIT_SIZE - 1);
+		n--;
+		ch->ch_txcount++;
+		len_written++;
+	}
+
+	/* Update the final tail */
+	circ->tail = tail & (UART_XMIT_SIZE - 1);
+
+	if (len_written > ch->ch_t_tlevel)
+		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
+
+	if (uart_circ_empty(circ))
+		uart_write_wakeup(&ch->uart_port);
+}
+
+static void cls_parse_modem(struct jsm_channel *ch, u8 signals)
+{
+	u8 msignals = signals;
+
+	jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
+		"neo_parse_modem: port: %d msignals: %x\n",
+		ch->ch_portnum, msignals);
+
+	/*
+	 * Scrub off lower bits.
+	 * They signify delta's, which I don't care about
+	 * Keep DDCD and DDSR though
+	 */
+	msignals &= 0xf8;
+
+	if (msignals & UART_MSR_DDCD)
+		uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_DCD);
+	if (msignals & UART_MSR_DDSR)
+		uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_CTS);
+
+	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;
+
+	jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
+		"Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
+		ch->ch_portnum,
+		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
+		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
+		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
+		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
+		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
+		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
+}
+
+/* Parse the ISR register for the specific port */
+static inline void cls_parse_isr(struct jsm_board *brd, uint port)
+{
+	struct jsm_channel *ch;
+	u8 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)
+		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 */
+			cls_copy_data_from_uart_to_queue(ch);
+			jsm_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);
+			spin_unlock_irqrestore(&ch->ch_lock, flags);
+			cls_copy_data_from_queue_to_uart(ch);
+		}
+
+		/*
+		 * CTS/RTS change of state:
+		 * 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 jsm_channel *ch)
+{
+	u8 tmp = 0;
+	u8 i = 0;
+
+	if (!ch)
+		return;
+
+	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT),
+						&ch->ch_cls_uart->isr_fcr);
+
+	for (i = 0; i < 10; i++) {
+		/* Check to see if the UART feels it completely flushed FIFO */
+		tmp = readb(&ch->ch_cls_uart->isr_fcr);
+		if (tmp & UART_FCR_CLEAR_XMIT) {
+			jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
+				"Still flushing TX UART... i: %d\n", i);
+			udelay(10);
+		} else
+			break;
+	}
+
+	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 jsm_channel *ch)
+{
+	if (!ch)
+		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_send_start_character(struct jsm_channel *ch)
+{
+	if (!ch)
+		return;
+
+	if (ch->ch_startc != __DISABLED_CHAR) {
+		ch->ch_xon_sends++;
+		writeb(ch->ch_startc, &ch->ch_cls_uart->txrx);
+	}
+}
+
+static void cls_send_stop_character(struct jsm_channel *ch)
+{
+	if (!ch)
+		return;
+
+	if (ch->ch_stopc != __DISABLED_CHAR) {
+		ch->ch_xoff_sends++;
+		writeb(ch->ch_stopc, &ch->ch_cls_uart->txrx);
+	}
+}
+
+/*
+ * cls_param()
+ * Send any/all changes to the line to the UART.
+ */
+static void cls_param(struct jsm_channel *ch)
+{
+	u8 lcr = 0;
+	u8 uart_lcr = 0;
+	u8 ier = 0;
+	u32 baud = 9600;
+	int quot = 0;
+	struct jsm_board *bd;
+	int i;
+	unsigned int cflag;
+
+	bd = ch->ch_bd;
+	if (!bd)
+		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;
+
+		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);
+		return;
+	}
+
+	cflag = C_BAUD(ch->uart_port.state->port.tty);
+	baud = 9600;
+	for (i = 0; i < ARRAY_SIZE(baud_rates); i++) {
+		if (baud_rates[i].cflag == cflag) {
+			baud = baud_rates[i].rate;
+			break;
+		}
+	}
+
+	if (ch->ch_flags & CH_BAUD0)
+		ch->ch_flags &= ~(CH_BAUD0);
+
+	if (ch->ch_c_cflag & PARENB)
+		lcr |= UART_LCR_PARITY;
+
+	if (!(ch->ch_c_cflag & PARODD))
+		lcr |= UART_LCR_EPAR;
+
+	/*
+	 * Not all platforms support mark/space parity,
+	 * so this will hide behind an ifdef.
+	 */
+#ifdef CMSPAR
+	if (ch->ch_c_cflag & CMSPAR)
+		lcr |= UART_LCR_SPAR;
+#endif
+
+	if (ch->ch_c_cflag & CSTOPB)
+		lcr |= UART_LCR_STOP;
+
+	switch (ch->ch_c_cflag & CSIZE) {
+	case CS5:
+		lcr |= UART_LCR_WLEN5;
+		break;
+	case CS6:
+		lcr |= UART_LCR_WLEN6;
+		break;
+	case CS7:
+		lcr |= UART_LCR_WLEN7;
+		break;
+	case CS8:
+	default:
+		lcr |= UART_LCR_WLEN8;
+		break;
+	}
+
+	ier = readb(&ch->ch_cls_uart->ier);
+	uart_lcr = readb(&ch->ch_cls_uart->lcr);
+
+	quot = ch->ch_bd->bd_dividend / baud;
+
+	if (quot != 0) {
+		writeb(UART_LCR_DLAB, &ch->ch_cls_uart->lcr);
+		writeb((quot & 0xff), &ch->ch_cls_uart->txrx);
+		writeb((quot >> 8), &ch->ch_cls_uart->ier);
+		writeb(lcr, &ch->ch_cls_uart->lcr);
+	}
+
+	if (uart_lcr != lcr)
+		writeb(lcr, &ch->ch_cls_uart->lcr);
+
+	if (ch->ch_c_cflag & CREAD)
+		ier |= (UART_IER_RDI | UART_IER_RLSI);
+
+	ier |= (UART_IER_THRI | UART_IER_MSI);
+
+	writeb(ier, &ch->ch_cls_uart->ier);
+
+	if (ch->ch_c_cflag & CRTSCTS)
+		cls_set_cts_flow_control(ch);
+	else if (ch->ch_c_iflag & IXON) {
+		/*
+		 * If start/stop is set to disable,
+		 * then we should disable flow control.
+		 */
+		if ((ch->ch_startc == __DISABLED_CHAR) ||
+			(ch->ch_stopc == __DISABLED_CHAR))
+			cls_set_no_output_flow_control(ch);
+		else
+			cls_set_ixon_flow_control(ch);
+	} else
+		cls_set_no_output_flow_control(ch);
+
+	if (ch->ch_c_cflag & CRTSCTS)
+		cls_set_rts_flow_control(ch);
+	else if (ch->ch_c_iflag & IXOFF) {
+		/*
+		 * If start/stop is set to disable,
+		 * then we should disable flow control.
+		 */
+		if ((ch->ch_startc == __DISABLED_CHAR) ||
+			(ch->ch_stopc == __DISABLED_CHAR))
+			cls_set_no_input_flow_control(ch);
+		else
+			cls_set_ixoff_flow_control(ch);
+	} else
+		cls_set_no_input_flow_control(ch);
+
+	cls_assert_modem_signals(ch);
+
+	/* get current status of the modem signals now */
+	cls_parse_modem(ch, readb(&ch->ch_cls_uart->msr));
+}
+
+/*
+ * cls_intr()
+ *
+ * Classic specific interrupt handler.
+ */
+static irqreturn_t cls_intr(int irq, void *voidbrd)
+{
+	struct jsm_board *brd = voidbrd;
+	unsigned long lock_flags;
+	unsigned char uart_poll;
+	uint i = 0;
+
+	/* Lock out the slow poller from running on this board. */
+	spin_lock_irqsave(&brd->bd_intr_lock, lock_flags);
+
+	/*
+	 * Check the board's global interrupt offset to see if we
+	 * acctually do have an interrupt pending on us.
+	 */
+	uart_poll = readb(brd->re_map_membase + UART_CLASSIC_POLL_ADDR_OFFSET);
+
+	jsm_dbg(INTR, &brd->pci_dev, "%s:%d uart_poll: %x\n",
+		__FILE__, __LINE__, uart_poll);
+
+	if (!uart_poll) {
+		jsm_dbg(INTR, &brd->pci_dev,
+			"Kernel interrupted to me, but no pending interrupts...\n");
+		spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
+		return IRQ_NONE;
+	}
+
+	/* At this point, we have at least SOMETHING to service, dig further. */
+
+	/* Parse each port to find out what caused the interrupt */
+	for (i = 0; i < brd->nasync; i++)
+		cls_parse_isr(brd, i);
+
+	spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
+
+	return IRQ_HANDLED;
+}
+
+/* Inits UART */
+static void cls_uart_init(struct jsm_channel *ch)
+{
+	unsigned char lcrb = readb(&ch->ch_cls_uart->lcr);
+	unsigned char isr_fcr = 0;
+
+	writeb(0, &ch->ch_cls_uart->ier);
+
+	/*
+	 * The Enhanced Register Set may only be accessed when
+	 * the Line Control Register is set to 0xBFh.
+	 */
+	writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
+
+	isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
+
+	/* Turn on Enhanced/Extended controls */
+	isr_fcr |= (UART_EXAR654_EFR_ECB);
+
+	writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
+
+	/* Write old LCR value back out, which turns enhanced access off */
+	writeb(lcrb, &ch->ch_cls_uart->lcr);
+
+	/* Clear out UART and FIFO */
+	readb(&ch->ch_cls_uart->txrx);
+
+	writeb((UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|UART_FCR_CLEAR_XMIT),
+						 &ch->ch_cls_uart->isr_fcr);
+	udelay(10);
+
+	ch->ch_flags |= (CH_FIFO_ENABLED | CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
+
+	readb(&ch->ch_cls_uart->lsr);
+	readb(&ch->ch_cls_uart->msr);
+}
+
+/*
+ * Turns off UART.
+ */
+static void cls_uart_off(struct jsm_channel *ch)
+{
+	/* Stop all interrupts from accurring. */
+	writeb(0, &ch->ch_cls_uart->ier);
+}
+
+/*
+ * cls_get_uarts_bytes_left.
+ * Returns 0 is nothing left in the FIFO, returns 1 otherwise.
+ *
+ * The channel lock MUST be held by the calling function.
+ */
+static u32 cls_get_uart_bytes_left(struct jsm_channel *ch)
+{
+	u8 left = 0;
+	u8 lsr = readb(&ch->ch_cls_uart->lsr);
+
+	/* Determine whether the Transmitter is empty or not */
+	if (!(lsr & UART_LSR_TEMT))
+		left = 1;
+	else {
+		ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
+		left = 0;
+	}
+
+	return left;
+}
+
+/*
+ * cls_send_break.
+ * Starts sending a break thru the UART.
+ *
+ * The channel lock MUST be held by the calling function.
+ */
+static void cls_send_break(struct jsm_channel *ch)
+{
+	/* Tell the UART to start sending the break */
+	if (!(ch->ch_flags & CH_BREAK_SENDING)) {
+		u8 temp = readb(&ch->ch_cls_uart->lcr);
+
+		writeb((temp | UART_LCR_SBC), &ch->ch_cls_uart->lcr);
+		ch->ch_flags |= (CH_BREAK_SENDING);
+	}
+}
+
+/*
+ * cls_send_immediate_char.
+ * Sends a specific character as soon as possible to the UART,
+ * jumping over any bytes that might be in the write queue.
+ *
+ * The channel lock MUST be held by the calling function.
+ */
+static void cls_send_immediate_char(struct jsm_channel *ch, unsigned char c)
+{
+	writeb(c, &ch->ch_cls_uart->txrx);
+}
+
+struct board_ops jsm_cls_ops = {
+	.intr =				cls_intr,
+	.uart_init =			cls_uart_init,
+	.uart_off =			cls_uart_off,
+	.param =			cls_param,
+	.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,
+	.clear_break =			cls_clear_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
+};
+