/*
 * UART driver for PNX8XXX SoCs
 *
 * Author: Per Hallsmark per.hallsmark@mvista.com
 * Ported to 2.6 kernel by EmbeddedAlley
 * Reworked by Vitaly Wool <vitalywool@gmail.com>
 *
 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 * Copyright (C) 2000 Deep Blue Solutions Ltd.
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of
 * any kind, whether express or implied.
 *
 */

#if defined(CONFIG_SERIAL_PNX8XXX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/serial_pnx8xxx.h>

#include <asm/io.h>
#include <asm/irq.h>

/* We'll be using StrongARM sa1100 serial port major/minor */
#define SERIAL_PNX8XXX_MAJOR    204
#define MINOR_START             5

#define NR_PORTS                2

#define PNX8XXX_ISR_PASS_LIMIT  256

/*
 * Convert from ignore_status_mask or read_status_mask to FIFO
 * and interrupt status bits
 */
#define SM_TO_FIFO(x)   ((x) >> 10)
#define SM_TO_ISTAT(x)  ((x) & 0x000001ff)
#define FIFO_TO_SM(x)   ((x) << 10)
#define ISTAT_TO_SM(x)  ((x) & 0x000001ff)

/*
 * This is the size of our serial port register set.
 */
#define UART_PORT_SIZE  0x1000

/*
 * This determines how often we check the modem status signals
 * for any change.  They generally aren't connected to an IRQ
 * so we have to poll them.  We also check immediately before
 * filling the TX fifo incase CTS has been dropped.
 */
#define MCTRL_TIMEOUT   (250*HZ/1000)

extern struct pnx8xxx_port pnx8xxx_ports[];

static inline int serial_in(struct pnx8xxx_port *sport, int offset)
{
        return (__raw_readl(sport->port.membase + offset));
}

static inline void serial_out(struct pnx8xxx_port *sport, int offset, int value)
{
        __raw_writel(value, sport->port.membase + offset);
}

/*
 * Handle any change of modem status signal since we were last called.
 */
static void pnx8xxx_mctrl_check(struct pnx8xxx_port *sport)
{
        unsigned int status, changed;

        status = sport->port.ops->get_mctrl(&sport->port);
        changed = status ^ sport->old_status;

        if (changed == 0)
                return;

        sport->old_status = status;

        if (changed & TIOCM_RI)
                sport->port.icount.rng++;
        if (changed & TIOCM_DSR)
                sport->port.icount.dsr++;
        if (changed & TIOCM_CAR)
                uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
        if (changed & TIOCM_CTS)
                uart_handle_cts_change(&sport->port, status & TIOCM_CTS);

        wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
}

/*
 * This is our per-port timeout handler, for checking the
 * modem status signals.
 */
static void pnx8xxx_timeout(unsigned long data)
{
        struct pnx8xxx_port *sport = (struct pnx8xxx_port *)data;
        unsigned long flags;

        if (sport->port.state) {
                spin_lock_irqsave(&sport->port.lock, flags);
                pnx8xxx_mctrl_check(sport);
                spin_unlock_irqrestore(&sport->port.lock, flags);

                mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
        }
}

/*
 * interrupts disabled on entry
 */
static void pnx8xxx_stop_tx(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        u32 ien;

        /* Disable TX intr */
        ien = serial_in(sport, PNX8XXX_IEN);
        serial_out(sport, PNX8XXX_IEN, ien & ~PNX8XXX_UART_INT_ALLTX);

        /* Clear all pending TX intr */
        serial_out(sport, PNX8XXX_ICLR, PNX8XXX_UART_INT_ALLTX);
}

/*
 * interrupts may not be disabled on entry
 */
static void pnx8xxx_start_tx(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        u32 ien;

        /* Clear all pending TX intr */
        serial_out(sport, PNX8XXX_ICLR, PNX8XXX_UART_INT_ALLTX);

        /* Enable TX intr */
        ien = serial_in(sport, PNX8XXX_IEN);
        serial_out(sport, PNX8XXX_IEN, ien | PNX8XXX_UART_INT_ALLTX);
}

/*
 * Interrupts enabled
 */
static void pnx8xxx_stop_rx(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        u32 ien;

        /* Disable RX intr */
        ien = serial_in(sport, PNX8XXX_IEN);
        serial_out(sport, PNX8XXX_IEN, ien & ~PNX8XXX_UART_INT_ALLRX);

        /* Clear all pending RX intr */
        serial_out(sport, PNX8XXX_ICLR, PNX8XXX_UART_INT_ALLRX);
}

/*
 * Set the modem control timer to fire immediately.
 */
static void pnx8xxx_enable_ms(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);

        mod_timer(&sport->timer, jiffies);
}

static void pnx8xxx_rx_chars(struct pnx8xxx_port *sport)
{
        unsigned int status, ch, flg;

        status = FIFO_TO_SM(serial_in(sport, PNX8XXX_FIFO)) |
                 ISTAT_TO_SM(serial_in(sport, PNX8XXX_ISTAT));
        while (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFIFO)) {
                ch = serial_in(sport, PNX8XXX_FIFO) & 0xff;

                sport->port.icount.rx++;

                flg = TTY_NORMAL;

                /*
                 * note that the error handling code is
                 * out of the main execution path
                 */
                if (status & (FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE |
                                        PNX8XXX_UART_FIFO_RXPAR |
                                        PNX8XXX_UART_FIFO_RXBRK) |
                              ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN))) {
                        if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXBRK)) {
                                status &= ~(FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE) |
                                        FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR));
                                sport->port.icount.brk++;
                                if (uart_handle_break(&sport->port))
                                        goto ignore_char;
                        } else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR))
                                sport->port.icount.parity++;
                        else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE))
                                sport->port.icount.frame++;
                        if (status & ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN))
                                sport->port.icount.overrun++;

                        status &= sport->port.read_status_mask;

                        if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR))
                                flg = TTY_PARITY;
                        else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE))
                                flg = TTY_FRAME;

#ifdef SUPPORT_SYSRQ
                        sport->port.sysrq = 0;
#endif
                }

                if (uart_handle_sysrq_char(&sport->port, ch))
                        goto ignore_char;

                uart_insert_char(&sport->port, status,
                                ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN), ch, flg);

        ignore_char:
                serial_out(sport, PNX8XXX_LCR, serial_in(sport, PNX8XXX_LCR) |
                                PNX8XXX_UART_LCR_RX_NEXT);
                status = FIFO_TO_SM(serial_in(sport, PNX8XXX_FIFO)) |
                         ISTAT_TO_SM(serial_in(sport, PNX8XXX_ISTAT));
        }

        spin_unlock(&sport->port.lock);
        tty_flip_buffer_push(&sport->port.state->port);
        spin_lock(&sport->port.lock);
}

static void pnx8xxx_tx_chars(struct pnx8xxx_port *sport)
{
        struct circ_buf *xmit = &sport->port.state->xmit;

        if (sport->port.x_char) {
                serial_out(sport, PNX8XXX_FIFO, sport->port.x_char);
                sport->port.icount.tx++;
                sport->port.x_char = 0;
                return;
        }

        /*
         * Check the modem control lines before
         * transmitting anything.
         */
        pnx8xxx_mctrl_check(sport);

        if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
                pnx8xxx_stop_tx(&sport->port);
                return;
        }

        /*
         * TX while bytes available
         */
        while (((serial_in(sport, PNX8XXX_FIFO) &
                                        PNX8XXX_UART_FIFO_TXFIFO) >> 16) < 16) {
                serial_out(sport, PNX8XXX_FIFO, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                sport->port.icount.tx++;
                if (uart_circ_empty(xmit))
                        break;
        }

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

        if (uart_circ_empty(xmit))
                pnx8xxx_stop_tx(&sport->port);
}

static irqreturn_t pnx8xxx_int(int irq, void *dev_id)
{
        struct pnx8xxx_port *sport = dev_id;
        unsigned int status;

        spin_lock(&sport->port.lock);
        /* Get the interrupts */
        status  = serial_in(sport, PNX8XXX_ISTAT) & serial_in(sport, PNX8XXX_IEN);

        /* Byte or break signal received */
        if (status & (PNX8XXX_UART_INT_RX | PNX8XXX_UART_INT_BREAK))
                pnx8xxx_rx_chars(sport);

        /* TX holding register empty - transmit a byte */
        if (status & PNX8XXX_UART_INT_TX)
                pnx8xxx_tx_chars(sport);

        /* Clear the ISTAT register */
        serial_out(sport, PNX8XXX_ICLR, status);

        spin_unlock(&sport->port.lock);
        return IRQ_HANDLED;
}

/*
 * Return TIOCSER_TEMT when transmitter is not busy.
 */
static unsigned int pnx8xxx_tx_empty(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);

        return serial_in(sport, PNX8XXX_FIFO) & PNX8XXX_UART_FIFO_TXFIFO_STA ? 0 : TIOCSER_TEMT;
}

static unsigned int pnx8xxx_get_mctrl(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        unsigned int mctrl = TIOCM_DSR;
        unsigned int msr;

        /* REVISIT */

        msr = serial_in(sport, PNX8XXX_MCR);

        mctrl |= msr & PNX8XXX_UART_MCR_CTS ? TIOCM_CTS : 0;
        mctrl |= msr & PNX8XXX_UART_MCR_DCD ? TIOCM_CAR : 0;

        return mctrl;
}

static void pnx8xxx_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
#if     0       /* FIXME */
        struct pnx8xxx_port *sport = (struct pnx8xxx_port *)port;
        unsigned int msr;
#endif
}

/*
 * Interrupts always disabled.
 */
static void pnx8xxx_break_ctl(struct uart_port *port, int break_state)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        unsigned long flags;
        unsigned int lcr;

        spin_lock_irqsave(&sport->port.lock, flags);
        lcr = serial_in(sport, PNX8XXX_LCR);
        if (break_state == -1)
                lcr |= PNX8XXX_UART_LCR_TXBREAK;
        else
                lcr &= ~PNX8XXX_UART_LCR_TXBREAK;
        serial_out(sport, PNX8XXX_LCR, lcr);
        spin_unlock_irqrestore(&sport->port.lock, flags);
}

static int pnx8xxx_startup(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        int retval;

        /*
         * Allocate the IRQ
         */
        retval = request_irq(sport->port.irq, pnx8xxx_int, 0,
                             "pnx8xxx-uart", sport);
        if (retval)
                return retval;

        /*
         * Finally, clear and enable interrupts
         */

        serial_out(sport, PNX8XXX_ICLR, PNX8XXX_UART_INT_ALLRX |
                             PNX8XXX_UART_INT_ALLTX);

        serial_out(sport, PNX8XXX_IEN, serial_in(sport, PNX8XXX_IEN) |
                            PNX8XXX_UART_INT_ALLRX |
                            PNX8XXX_UART_INT_ALLTX);

        /*
         * Enable modem status interrupts
         */
        spin_lock_irq(&sport->port.lock);
        pnx8xxx_enable_ms(&sport->port);
        spin_unlock_irq(&sport->port.lock);

        return 0;
}

static void pnx8xxx_shutdown(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        int lcr;

        /*
         * Stop our timer.
         */
        del_timer_sync(&sport->timer);

        /*
         * Disable all interrupts
         */
        serial_out(sport, PNX8XXX_IEN, 0);

        /*
         * Reset the Tx and Rx FIFOS, disable the break condition
         */
        lcr = serial_in(sport, PNX8XXX_LCR);
        lcr &= ~PNX8XXX_UART_LCR_TXBREAK;
        lcr |= PNX8XXX_UART_LCR_TX_RST | PNX8XXX_UART_LCR_RX_RST;
        serial_out(sport, PNX8XXX_LCR, lcr);

        /*
         * Clear all interrupts
         */
        serial_out(sport, PNX8XXX_ICLR, PNX8XXX_UART_INT_ALLRX |
                             PNX8XXX_UART_INT_ALLTX);

        /*
         * Free the interrupt
         */
        free_irq(sport->port.irq, sport);
}

static void
pnx8xxx_set_termios(struct uart_port *port, struct ktermios *termios,
                   struct ktermios *old)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        unsigned long flags;
        unsigned int lcr_fcr, old_ien, baud, quot;
        unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;

        /*
         * We only support CS7 and CS8.
         */
        while ((termios->c_cflag & CSIZE) != CS7 &&
               (termios->c_cflag & CSIZE) != CS8) {
                termios->c_cflag &= ~CSIZE;
                termios->c_cflag |= old_csize;
                old_csize = CS8;
        }

        if ((termios->c_cflag & CSIZE) == CS8)
                lcr_fcr = PNX8XXX_UART_LCR_8BIT;
        else
                lcr_fcr = 0;

        if (termios->c_cflag & CSTOPB)
                lcr_fcr |= PNX8XXX_UART_LCR_2STOPB;
        if (termios->c_cflag & PARENB) {
                lcr_fcr |= PNX8XXX_UART_LCR_PAREN;
                if (!(termios->c_cflag & PARODD))
                        lcr_fcr |= PNX8XXX_UART_LCR_PAREVN;
        }

        /*
         * Ask the core to calculate the divisor for us.
         */
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
        quot = uart_get_divisor(port, baud);

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

        sport->port.read_status_mask = ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN) |
                                ISTAT_TO_SM(PNX8XXX_UART_INT_EMPTY) |
                                ISTAT_TO_SM(PNX8XXX_UART_INT_RX);
        if (termios->c_iflag & INPCK)
                sport->port.read_status_mask |=
                        FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE) |
                        FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR);
        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
                sport->port.read_status_mask |=
                        ISTAT_TO_SM(PNX8XXX_UART_INT_BREAK);

        /*
         * Characters to ignore
         */
        sport->port.ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                sport->port.ignore_status_mask |=
                        FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE) |
                        FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR);
        if (termios->c_iflag & IGNBRK) {
                sport->port.ignore_status_mask |=
                        ISTAT_TO_SM(PNX8XXX_UART_INT_BREAK);
                /*
                 * If we're ignoring parity and break indicators,
                 * ignore overruns too (for real raw support).
                 */
                if (termios->c_iflag & IGNPAR)
                        sport->port.ignore_status_mask |=
                                ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN);
        }

        /*
         * ignore all characters if CREAD is not set
         */
        if ((termios->c_cflag & CREAD) == 0)
                sport->port.ignore_status_mask |=
                        ISTAT_TO_SM(PNX8XXX_UART_INT_RX);

        del_timer_sync(&sport->timer);

        /*
         * Update the per-port timeout.
         */
        uart_update_timeout(port, termios->c_cflag, baud);

        /*
         * disable interrupts and drain transmitter
         */
        old_ien = serial_in(sport, PNX8XXX_IEN);
        serial_out(sport, PNX8XXX_IEN, old_ien & ~(PNX8XXX_UART_INT_ALLTX |
                                        PNX8XXX_UART_INT_ALLRX));

        while (serial_in(sport, PNX8XXX_FIFO) & PNX8XXX_UART_FIFO_TXFIFO_STA)
                barrier();

        /* then, disable everything */
        serial_out(sport, PNX8XXX_IEN, 0);

        /* Reset the Rx and Tx FIFOs too */
        lcr_fcr |= PNX8XXX_UART_LCR_TX_RST;
        lcr_fcr |= PNX8XXX_UART_LCR_RX_RST;

        /* set the parity, stop bits and data size */
        serial_out(sport, PNX8XXX_LCR, lcr_fcr);

        /* set the baud rate */
        quot -= 1;
        serial_out(sport, PNX8XXX_BAUD, quot);

        serial_out(sport, PNX8XXX_ICLR, -1);

        serial_out(sport, PNX8XXX_IEN, old_ien);

        if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
                pnx8xxx_enable_ms(&sport->port);

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

static const char *pnx8xxx_type(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);

        return sport->port.type == PORT_PNX8XXX ? "PNX8XXX" : NULL;
}

/*
 * Release the memory region(s) being used by 'port'.
 */
static void pnx8xxx_release_port(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);

        release_mem_region(sport->port.mapbase, UART_PORT_SIZE);
}

/*
 * Request the memory region(s) being used by 'port'.
 */
static int pnx8xxx_request_port(struct uart_port *port)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        return request_mem_region(sport->port.mapbase, UART_PORT_SIZE,
                        "pnx8xxx-uart") != NULL ? 0 : -EBUSY;
}

/*
 * Configure/autoconfigure the port.
 */
static void pnx8xxx_config_port(struct uart_port *port, int flags)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);

        if (flags & UART_CONFIG_TYPE &&
            pnx8xxx_request_port(&sport->port) == 0)
                sport->port.type = PORT_PNX8XXX;
}

/*
 * Verify the new serial_struct (for TIOCSSERIAL).
 * The only change we allow are to the flags and type, and
 * even then only between PORT_PNX8XXX and PORT_UNKNOWN
 */
static int
pnx8xxx_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        int ret = 0;

        if (ser->type != PORT_UNKNOWN && ser->type != PORT_PNX8XXX)
                ret = -EINVAL;
        if (sport->port.irq != ser->irq)
                ret = -EINVAL;
        if (ser->io_type != SERIAL_IO_MEM)
                ret = -EINVAL;
        if (sport->port.uartclk / 16 != ser->baud_base)
                ret = -EINVAL;
        if ((void *)sport->port.mapbase != ser->iomem_base)
                ret = -EINVAL;
        if (sport->port.iobase != ser->port)
                ret = -EINVAL;
        if (ser->hub6 != 0)
                ret = -EINVAL;
        return ret;
}

static struct uart_ops pnx8xxx_pops = {
        .tx_empty       = pnx8xxx_tx_empty,
        .set_mctrl      = pnx8xxx_set_mctrl,
        .get_mctrl      = pnx8xxx_get_mctrl,
        .stop_tx        = pnx8xxx_stop_tx,
        .start_tx       = pnx8xxx_start_tx,
        .stop_rx        = pnx8xxx_stop_rx,
        .enable_ms      = pnx8xxx_enable_ms,
        .break_ctl      = pnx8xxx_break_ctl,
        .startup        = pnx8xxx_startup,
        .shutdown       = pnx8xxx_shutdown,
        .set_termios    = pnx8xxx_set_termios,
        .type           = pnx8xxx_type,
        .release_port   = pnx8xxx_release_port,
        .request_port   = pnx8xxx_request_port,
        .config_port    = pnx8xxx_config_port,
        .verify_port    = pnx8xxx_verify_port,
};


/*
 * Setup the PNX8XXX serial ports.
 *
 * Note also that we support "console=ttySx" where "x" is either 0 or 1.
 */
static void __init pnx8xxx_init_ports(void)
{
        static int first = 1;
        int i;

        if (!first)
                return;
        first = 0;

        for (i = 0; i < NR_PORTS; i++) {
                init_timer(&pnx8xxx_ports[i].timer);
                pnx8xxx_ports[i].timer.function = pnx8xxx_timeout;
                pnx8xxx_ports[i].timer.data     = (unsigned long)&pnx8xxx_ports[i];
                pnx8xxx_ports[i].port.ops = &pnx8xxx_pops;
        }
}

#ifdef CONFIG_SERIAL_PNX8XXX_CONSOLE

static void pnx8xxx_console_putchar(struct uart_port *port, int ch)
{
        struct pnx8xxx_port *sport =
                container_of(port, struct pnx8xxx_port, port);
        int status;

        do {
                /* Wait for UART_TX register to empty */
                status = serial_in(sport, PNX8XXX_FIFO);
        } while (status & PNX8XXX_UART_FIFO_TXFIFO);
        serial_out(sport, PNX8XXX_FIFO, ch);
}

/*
 * Interrupts are disabled on entering
 */static void
pnx8xxx_console_write(struct console *co, const char *s, unsigned int count)
{
        struct pnx8xxx_port *sport = &pnx8xxx_ports[co->index];
        unsigned int old_ien, status;

        /*
         *      First, save IEN and then disable interrupts
         */
        old_ien = serial_in(sport, PNX8XXX_IEN);
        serial_out(sport, PNX8XXX_IEN, old_ien & ~(PNX8XXX_UART_INT_ALLTX |
                                        PNX8XXX_UART_INT_ALLRX));

        uart_console_write(&sport->port, s, count, pnx8xxx_console_putchar);

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore IEN
         */
        do {
                /* Wait for UART_TX register to empty */
                status = serial_in(sport, PNX8XXX_FIFO);
        } while (status & PNX8XXX_UART_FIFO_TXFIFO);

        /* Clear TX and EMPTY interrupt */
        serial_out(sport, PNX8XXX_ICLR, PNX8XXX_UART_INT_TX |
                             PNX8XXX_UART_INT_EMPTY);

        serial_out(sport, PNX8XXX_IEN, old_ien);
}

static int __init
pnx8xxx_console_setup(struct console *co, char *options)
{
        struct pnx8xxx_port *sport;
        int baud = 38400;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        /*
         * Check whether an invalid uart number has been specified, and
         * if so, search for the first available port that does have
         * console support.
         */
        if (co->index == -1 || co->index >= NR_PORTS)
                co->index = 0;
        sport = &pnx8xxx_ports[co->index];

        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);

        return uart_set_options(&sport->port, co, baud, parity, bits, flow);
}

static struct uart_driver pnx8xxx_reg;
static struct console pnx8xxx_console = {
        .name           = "ttyS",
        .write          = pnx8xxx_console_write,
        .device         = uart_console_device,
        .setup          = pnx8xxx_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &pnx8xxx_reg,
};

static int __init pnx8xxx_rs_console_init(void)
{
        pnx8xxx_init_ports();
        register_console(&pnx8xxx_console);
        return 0;
}
console_initcall(pnx8xxx_rs_console_init);

#define PNX8XXX_CONSOLE &pnx8xxx_console
#else
#define PNX8XXX_CONSOLE NULL
#endif

static struct uart_driver pnx8xxx_reg = {
        .owner                  = THIS_MODULE,
        .driver_name            = "ttyS",
        .dev_name               = "ttyS",
        .major                  = SERIAL_PNX8XXX_MAJOR,
        .minor                  = MINOR_START,
        .nr                     = NR_PORTS,
        .cons                   = PNX8XXX_CONSOLE,
};

static int pnx8xxx_serial_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct pnx8xxx_port *sport = platform_get_drvdata(pdev);

        return uart_suspend_port(&pnx8xxx_reg, &sport->port);
}

static int pnx8xxx_serial_resume(struct platform_device *pdev)
{
        struct pnx8xxx_port *sport = platform_get_drvdata(pdev);

        return uart_resume_port(&pnx8xxx_reg, &sport->port);
}

static int pnx8xxx_serial_probe(struct platform_device *pdev)
{
        struct resource *res = pdev->resource;
        int i;

        for (i = 0; i < pdev->num_resources; i++, res++) {
                if (!(res->flags & IORESOURCE_MEM))
                        continue;

                for (i = 0; i < NR_PORTS; i++) {
                        if (pnx8xxx_ports[i].port.mapbase != res->start)
                                continue;

                        pnx8xxx_ports[i].port.dev = &pdev->dev;
                        uart_add_one_port(&pnx8xxx_reg, &pnx8xxx_ports[i].port);
                        platform_set_drvdata(pdev, &pnx8xxx_ports[i]);
                        break;
                }
        }

        return 0;
}

static int pnx8xxx_serial_remove(struct platform_device *pdev)
{
        struct pnx8xxx_port *sport = platform_get_drvdata(pdev);

        if (sport)
                uart_remove_one_port(&pnx8xxx_reg, &sport->port);

        return 0;
}

static struct platform_driver pnx8xxx_serial_driver = {
        .driver         = {
                .name   = "pnx8xxx-uart",
        },
        .probe          = pnx8xxx_serial_probe,
        .remove         = pnx8xxx_serial_remove,
        .suspend        = pnx8xxx_serial_suspend,
        .resume         = pnx8xxx_serial_resume,
};

static int __init pnx8xxx_serial_init(void)
{
        int ret;

        printk(KERN_INFO "Serial: PNX8XXX driver\n");

        pnx8xxx_init_ports();

        ret = uart_register_driver(&pnx8xxx_reg);
        if (ret == 0) {
                ret = platform_driver_register(&pnx8xxx_serial_driver);
                if (ret)
                        uart_unregister_driver(&pnx8xxx_reg);
        }
        return ret;
}

static void __exit pnx8xxx_serial_exit(void)
{
        platform_driver_unregister(&pnx8xxx_serial_driver);
        uart_unregister_driver(&pnx8xxx_reg);
}

module_init(pnx8xxx_serial_init);
module_exit(pnx8xxx_serial_exit);

MODULE_AUTHOR("Embedded Alley Solutions, Inc.");
MODULE_DESCRIPTION("PNX8XXX SoCs serial port driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_PNX8XXX_MAJOR);
MODULE_ALIAS("platform:pnx8xxx-uart");