[PATCH] ppc32: add 405EP cpu_spec entry

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / serial / imx.c

/*
 *  linux/drivers/serial/imx.c
 *
 *  Driver for Motorola IMX serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Author: Sascha Hauer <sascha@saschahauer.de>
 *  Copyright (C) 2004 Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * [29-Mar-2005] Mike Lee
 * Added hardware handshake
 */
#include <linux/config.h>

#if defined(CONFIG_SERIAL_IMX_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/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>

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

/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_IMX_MAJOR        204
#define MINOR_START             41

#define NR_PORTS                2

#define IMX_ISR_PASS_LIMIT      256

/*
 * This is the size of our serial port register set.
 */
#define UART_PORT_SIZE  0x100

/*
 * 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)

#define DRIVER_NAME "IMX-uart"

struct imx_port {
        struct uart_port        port;
        struct timer_list       timer;
        unsigned int            old_status;
        int txirq,rxirq;
};

/*
 * Handle any change of modem status signal since we were last called.
 */
static void imx_mctrl_check(struct imx_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.info->delta_msr_wait);
}

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

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

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

/*
 * interrupts disabled on entry
 */
static void imx_stop_tx(struct uart_port *port, unsigned int tty_stop)
{
        struct imx_port *sport = (struct imx_port *)port;
        UCR1((u32)sport->port.membase) &= ~UCR1_TXMPTYEN;
}

/*
 * interrupts disabled on entry
 */
static void imx_stop_rx(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;
        UCR2((u32)sport->port.membase) &= ~UCR2_RXEN;
}

/*
 * Set the modem control timer to fire immediately.
 */
static void imx_enable_ms(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;

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

static inline void imx_transmit_buffer(struct imx_port *sport)
{
        struct circ_buf *xmit = &sport->port.info->xmit;

        do {
                /* send xmit->buf[xmit->tail]
                 * out the port here */
                URTX0((u32)sport->port.membase) = xmit->buf[xmit->tail];
                xmit->tail = (xmit->tail + 1) &
                         (UART_XMIT_SIZE - 1);
                sport->port.icount.tx++;
                if (uart_circ_empty(xmit))
                        break;
        } while (!(UTS((u32)sport->port.membase) & UTS_TXFULL));

        if (uart_circ_empty(xmit))
                imx_stop_tx(&sport->port, 0);
}

/*
 * interrupts disabled on entry
 */
static void imx_start_tx(struct uart_port *port, unsigned int tty_start)
{
        struct imx_port *sport = (struct imx_port *)port;

        UCR1((u32)sport->port.membase) |= UCR1_TXMPTYEN;

        if(UTS((u32)sport->port.membase) & UTS_TXEMPTY)
                imx_transmit_buffer(sport);
}

static irqreturn_t imx_txint(int irq, void *dev_id, struct pt_regs *regs)
{
        struct imx_port *sport = (struct imx_port *)dev_id;
        struct circ_buf *xmit = &sport->port.info->xmit;
        unsigned long flags;

        spin_lock_irqsave(&sport->port.lock,flags);
        if (sport->port.x_char)
        {
                /* Send next char */
                URTX0((u32)sport->port.membase) = sport->port.x_char;
                goto out;
        }

        if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
                imx_stop_tx(&sport->port, 0);
                goto out;
        }

        imx_transmit_buffer(sport);

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

out:
        spin_unlock_irqrestore(&sport->port.lock,flags);
        return IRQ_HANDLED;
}

static irqreturn_t imx_rxint(int irq, void *dev_id, struct pt_regs *regs)
{
        struct imx_port *sport = dev_id;
        unsigned int rx,flg,ignored = 0;
        struct tty_struct *tty = sport->port.info->tty;
        unsigned long flags;

        rx = URXD0((u32)sport->port.membase);
        spin_lock_irqsave(&sport->port.lock,flags);

        do {
                flg = TTY_NORMAL;
                sport->port.icount.rx++;

                if( USR2((u32)sport->port.membase) & USR2_BRCD ) {
                        USR2((u32)sport->port.membase) |= USR2_BRCD;
                        if(uart_handle_break(&sport->port))
                                goto ignore_char;
                }

                if (uart_handle_sysrq_char
                            (&sport->port, (unsigned char)rx, regs))
                        goto ignore_char;

                if( rx & (URXD_PRERR | URXD_OVRRUN | URXD_FRMERR) )
                        goto handle_error;

        error_return:
                tty_insert_flip_char(tty, rx, flg);

                if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                        goto out;

        ignore_char:
                rx = URXD0((u32)sport->port.membase);
        } while(rx & URXD_CHARRDY);

out:
        spin_unlock_irqrestore(&sport->port.lock,flags);
        tty_flip_buffer_push(tty);
        return IRQ_HANDLED;

handle_error:
        if (rx & URXD_PRERR)
                sport->port.icount.parity++;
        else if (rx & URXD_FRMERR)
                sport->port.icount.frame++;
        if (rx & URXD_OVRRUN)
                sport->port.icount.overrun++;

        if (rx & sport->port.ignore_status_mask) {
                if (++ignored > 100)
                        goto out;
                goto ignore_char;
        }

        rx &= sport->port.read_status_mask;

        if (rx & URXD_PRERR)
                flg = TTY_PARITY;
        else if (rx & URXD_FRMERR)
                flg = TTY_FRAME;
        if (rx & URXD_OVRRUN)
                flg = TTY_OVERRUN;

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

/*
 * Return TIOCSER_TEMT when transmitter is not busy.
 */
static unsigned int imx_tx_empty(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;

        return USR2((u32)sport->port.membase) & USR2_TXDC ?  TIOCSER_TEMT : 0;
}

static unsigned int imx_get_mctrl(struct uart_port *port)
{
        return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}

static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}

/*
 * Interrupts always disabled.
 */
static void imx_break_ctl(struct uart_port *port, int break_state)
{
        struct imx_port *sport = (struct imx_port *)port;
        unsigned long flags;

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

        if ( break_state != 0 )
                UCR1((u32)sport->port.membase) |= UCR1_SNDBRK;
        else
                UCR1((u32)sport->port.membase) &= ~UCR1_SNDBRK;

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

#define TXTL 2 /* reset default */
#define RXTL 1 /* reset default */

static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
{
        unsigned int val;
        unsigned int ufcr_rfdiv;

        /* set receiver / transmitter trigger level.
         * RFDIV is set such way to satisfy requested uartclk value
         */
        val = TXTL<<10 | RXTL;
        ufcr_rfdiv = (imx_get_perclk1() + sport->port.uartclk / 2) / sport->port.uartclk;

        if(!ufcr_rfdiv)
                ufcr_rfdiv = 1;

        if(ufcr_rfdiv >= 7)
                ufcr_rfdiv = 6;
        else
                ufcr_rfdiv = 6 - ufcr_rfdiv;

        val |= UFCR_RFDIV & (ufcr_rfdiv << 7);

        UFCR((u32)sport->port.membase) = val;

        return 0;
}

static int imx_startup(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;
        int retval;
        unsigned long flags;

        imx_setup_ufcr(sport, 0);

        /* disable the DREN bit (Data Ready interrupt enable) before
         * requesting IRQs
         */
        UCR4((u32)sport->port.membase) &= ~UCR4_DREN;

        /*
         * Allocate the IRQ
         */
        retval = request_irq(sport->rxirq, imx_rxint, 0,
                             DRIVER_NAME, sport);
        if (retval) goto error_out2;

        retval = request_irq(sport->txirq, imx_txint, 0,
                             "imx-uart", sport);
        if (retval) goto error_out1;

        /*
         * Finally, clear and enable interrupts
         */

        UCR1((u32)sport->port.membase) |=
                         (UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_UARTEN);

        UCR2((u32)sport->port.membase) |= (UCR2_RXEN | UCR2_TXEN);
        /*
         * Enable modem status interrupts
         */
        spin_lock_irqsave(&sport->port.lock,flags);
        imx_enable_ms(&sport->port);
        spin_unlock_irqrestore(&sport->port.lock,flags);

        return 0;

error_out1:
        free_irq(sport->rxirq, sport);
error_out2:
        free_irq(sport->txirq, sport);
        return retval;
}

static void imx_shutdown(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;

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

        /*
         * Free the interrupts
         */
        free_irq(sport->txirq, sport);
        free_irq(sport->rxirq, sport);

        /*
         * Disable all interrupts, port and break condition.
         */

        UCR1((u32)sport->port.membase) &=
                         ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_UARTEN);
}

static void
imx_set_termios(struct uart_port *port, struct termios *termios,
                   struct termios *old)
{
        struct imx_port *sport = (struct imx_port *)port;
        unsigned long flags;
        unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
        unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;

        /*
         * If we don't support modem control lines, don't allow
         * these to be set.
         */
        if (0) {
                termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
                termios->c_cflag |= CLOCAL;
        }

        /*
         * 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)
                ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
        else
                ucr2 = UCR2_SRST | UCR2_IRTS;

        if (termios->c_cflag & CRTSCTS) {
                ucr2 &= ~UCR2_IRTS;
                ucr2 |= UCR2_CTSC;
        }

        if (termios->c_cflag & CSTOPB)
                ucr2 |= UCR2_STPB;
        if (termios->c_cflag & PARENB) {
                ucr2 |= UCR2_PREN;
                if (!(termios->c_cflag & PARODD))
                        ucr2 |= UCR2_PROE;
        }

        /*
         * 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 = 0;
        if (termios->c_iflag & INPCK)
                sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
        if (termios->c_iflag & (BRKINT | PARMRK))
                sport->port.read_status_mask |= URXD_BRK;

        /*
         * Characters to ignore
         */
        sport->port.ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                sport->port.ignore_status_mask |= URXD_PRERR;
        if (termios->c_iflag & IGNBRK) {
                sport->port.ignore_status_mask |= URXD_BRK;
                /*
                 * 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 |= URXD_OVRRUN;
        }

        del_timer_sync(&sport->timer);

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

        /*
         * disable interrupts and drain transmitter
         */
        old_ucr1 = UCR1((u32)sport->port.membase);
        UCR1((u32)sport->port.membase) &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN);

        while ( !(USR2((u32)sport->port.membase) & USR2_TXDC))
                barrier();

        /* then, disable everything */
        old_txrxen = UCR2((u32)sport->port.membase) & ( UCR2_TXEN | UCR2_RXEN );
        UCR2((u32)sport->port.membase) &= ~( UCR2_TXEN | UCR2_RXEN);

        /* set the parity, stop bits and data size */
        UCR2((u32)sport->port.membase) = ucr2;

        /* set the baud rate. We assume uartclk = 16 MHz
         *
         * baud * 16   UBIR - 1
         * --------- = --------
         *  uartclk    UBMR - 1
         */
        UBIR((u32)sport->port.membase) = (baud / 100) - 1;
        UBMR((u32)sport->port.membase) = 10000 - 1;

        UCR1((u32)sport->port.membase) = old_ucr1;
        UCR2((u32)sport->port.membase) |= old_txrxen;

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

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

static const char *imx_type(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;

        return sport->port.type == PORT_IMX ? "IMX" : NULL;
}

/*
 * Release the memory region(s) being used by 'port'.
 */
static void imx_release_port(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;

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

/*
 * Request the memory region(s) being used by 'port'.
 */
static int imx_request_port(struct uart_port *port)
{
        struct imx_port *sport = (struct imx_port *)port;

        return request_mem_region(sport->port.mapbase, UART_PORT_SIZE,
                        "imx-uart") != NULL ? 0 : -EBUSY;
}

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

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

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

        if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
                ret = -EINVAL;
        if (sport->port.irq != ser->irq)
                ret = -EINVAL;
        if (ser->io_type != UPIO_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 imx_pops = {
        .tx_empty       = imx_tx_empty,
        .set_mctrl      = imx_set_mctrl,
        .get_mctrl      = imx_get_mctrl,
        .stop_tx        = imx_stop_tx,
        .start_tx       = imx_start_tx,
        .stop_rx        = imx_stop_rx,
        .enable_ms      = imx_enable_ms,
        .break_ctl      = imx_break_ctl,
        .startup        = imx_startup,
        .shutdown       = imx_shutdown,
        .set_termios    = imx_set_termios,
        .type           = imx_type,
        .release_port   = imx_release_port,
        .request_port   = imx_request_port,
        .config_port    = imx_config_port,
        .verify_port    = imx_verify_port,
};

static struct imx_port imx_ports[] = {
        {
        .txirq  = UART1_MINT_TX,
        .rxirq  = UART1_MINT_RX,
        .port   = {
                .type           = PORT_IMX,
                .iotype         = SERIAL_IO_MEM,
                .membase        = (void *)IMX_UART1_BASE,
                .mapbase        = IMX_UART1_BASE, /* FIXME */
                .irq            = UART1_MINT_RX,
                .uartclk        = 16000000,
                .fifosize       = 8,
                .flags          = ASYNC_BOOT_AUTOCONF,
                .ops            = &imx_pops,
                .line           = 0,
        },
        }, {
        .txirq  = UART2_MINT_TX,
        .rxirq  = UART2_MINT_RX,
        .port   = {
                .type           = PORT_IMX,
                .iotype         = SERIAL_IO_MEM,
                .membase        = (void *)IMX_UART2_BASE,
                .mapbase        = IMX_UART2_BASE, /* FIXME */
                .irq            = UART2_MINT_RX,
                .uartclk        = 16000000,
                .fifosize       = 8,
                .flags          = ASYNC_BOOT_AUTOCONF,
                .ops            = &imx_pops,
                .line           = 1,
        },
        }
};

/*
 * Setup the IMX serial ports.
 * Note also that we support "console=ttySMXx" where "x" is either 0 or 1.
 * Which serial port this ends up being depends on the machine you're
 * running this kernel on.  I'm not convinced that this is a good idea,
 * but that's the way it traditionally works.
 *
 */
static void __init imx_init_ports(void)
{
        static int first = 1;
        int i;

        if (!first)
                return;
        first = 0;

        for (i = 0; i < ARRAY_SIZE(imx_ports); i++) {
                init_timer(&imx_ports[i].timer);
                imx_ports[i].timer.function = imx_timeout;
                imx_ports[i].timer.data     = (unsigned long)&imx_ports[i];
        }

        imx_gpio_mode(PC9_PF_UART1_CTS);
        imx_gpio_mode(PC10_PF_UART1_RTS);
        imx_gpio_mode(PC11_PF_UART1_TXD);
        imx_gpio_mode(PC12_PF_UART1_RXD);
        imx_gpio_mode(PB28_PF_UART2_CTS);
        imx_gpio_mode(PB29_PF_UART2_RTS);

        imx_gpio_mode(PB30_PF_UART2_TXD);
        imx_gpio_mode(PB31_PF_UART2_RXD);

#if 0 /* We don't need these, on the mx1 the _modem_ side of the uart
       * is implemented.
       */
        imx_gpio_mode(PD7_AF_UART2_DTR);
        imx_gpio_mode(PD8_AF_UART2_DCD);
        imx_gpio_mode(PD9_AF_UART2_RI);
        imx_gpio_mode(PD10_AF_UART2_DSR);
#endif


}

#ifdef CONFIG_SERIAL_IMX_CONSOLE

/*
 * Interrupts are disabled on entering
 */
static void
imx_console_write(struct console *co, const char *s, unsigned int count)
{
        struct imx_port *sport = &imx_ports[co->index];
        unsigned int old_ucr1, old_ucr2, i;

        /*
         *      First, save UCR1/2 and then disable interrupts
         */
        old_ucr1 = UCR1((u32)sport->port.membase);
        old_ucr2 = UCR2((u32)sport->port.membase);

        UCR1((u32)sport->port.membase) =
                           (old_ucr1 | UCR1_UARTCLKEN | UCR1_UARTEN)
                           & ~(UCR1_TXMPTYEN | UCR1_RRDYEN);
        UCR2((u32)sport->port.membase) = old_ucr2 | UCR2_TXEN;

        /*
         *      Now, do each character
         */
        for (i = 0; i < count; i++) {

                while ((UTS((u32)sport->port.membase) & UTS_TXFULL))
                        barrier();

                URTX0((u32)sport->port.membase) = s[i];

                if (s[i] == '\n') {
                        while ((UTS((u32)sport->port.membase) & UTS_TXFULL))
                                barrier();
                        URTX0((u32)sport->port.membase) = '\r';
                }
        }

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore UCR1/2
         */
        while (!(USR2((u32)sport->port.membase) & USR2_TXDC));

        UCR1((u32)sport->port.membase) = old_ucr1;
        UCR2((u32)sport->port.membase) = old_ucr2;
}

/*
 * If the port was already initialised (eg, by a boot loader),
 * try to determine the current setup.
 */
static void __init
imx_console_get_options(struct imx_port *sport, int *baud,
                           int *parity, int *bits)
{

        if ( UCR1((u32)sport->port.membase) | UCR1_UARTEN ) {
                /* ok, the port was enabled */
                unsigned int ucr2, ubir,ubmr, uartclk;
                unsigned int baud_raw;
                unsigned int ucfr_rfdiv;

                ucr2 = UCR2((u32)sport->port.membase);

                *parity = 'n';
                if (ucr2 & UCR2_PREN) {
                        if (ucr2 & UCR2_PROE)
                                *parity = 'o';
                        else
                                *parity = 'e';
                }

                if (ucr2 & UCR2_WS)
                        *bits = 8;
                else
                        *bits = 7;

                ubir = UBIR((u32)sport->port.membase) & 0xffff;
                ubmr = UBMR((u32)sport->port.membase) & 0xffff;


                ucfr_rfdiv = (UFCR((u32)sport->port.membase) & UFCR_RFDIV) >> 7;
                if (ucfr_rfdiv == 6)
                        ucfr_rfdiv = 7;
                else
                        ucfr_rfdiv = 6 - ucfr_rfdiv;

                uartclk = imx_get_perclk1();
                uartclk /= ucfr_rfdiv;

                {       /*
                         * The next code provides exact computation of
                         *   baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
                         * without need of float support or long long division,
                         * which would be required to prevent 32bit arithmetic overflow
                         */
                        unsigned int mul = ubir + 1;
                        unsigned int div = 16 * (ubmr + 1);
                        unsigned int rem = uartclk % div;

                        baud_raw = (uartclk / div) * mul;
                        baud_raw += (rem * mul + div / 2) / div;
                        *baud = (baud_raw + 50) / 100 * 100;
                }

                if(*baud != baud_raw)
                        printk(KERN_INFO "Serial: Console IMX rounded baud rate from %d to %d\n",
                                baud_raw, *baud);
        }
}

static int __init
imx_console_setup(struct console *co, char *options)
{
        struct imx_port *sport;
        int baud = 9600;
        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 >= ARRAY_SIZE(imx_ports))
                co->index = 0;
        sport = &imx_ports[co->index];

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

        imx_setup_ufcr(sport, 0);

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

extern struct uart_driver imx_reg;
static struct console imx_console = {
        .name           = "ttySMX",
        .write          = imx_console_write,
        .device         = uart_console_device,
        .setup          = imx_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &imx_reg,
};

static int __init imx_rs_console_init(void)
{
        imx_init_ports();
        register_console(&imx_console);
        return 0;
}
console_initcall(imx_rs_console_init);

#define IMX_CONSOLE     &imx_console
#else
#define IMX_CONSOLE     NULL
#endif

static struct uart_driver imx_reg = {
        .owner          = THIS_MODULE,
        .driver_name    = DRIVER_NAME,
        .dev_name       = "ttySMX",
        .devfs_name     = "ttsmx/",
        .major          = SERIAL_IMX_MAJOR,
        .minor          = MINOR_START,
        .nr             = ARRAY_SIZE(imx_ports),
        .cons           = IMX_CONSOLE,
};

static int serial_imx_suspend(struct device *_dev, pm_message_t state, u32 level)
{
        struct imx_port *sport = dev_get_drvdata(_dev);

        if (sport && level == SUSPEND_DISABLE)
                uart_suspend_port(&imx_reg, &sport->port);

        return 0;
}

static int serial_imx_resume(struct device *_dev, u32 level)
{
        struct imx_port *sport = dev_get_drvdata(_dev);

        if (sport && level == RESUME_ENABLE)
                uart_resume_port(&imx_reg, &sport->port);

        return 0;
}

static int serial_imx_probe(struct device *_dev)
{
        struct platform_device *dev = to_platform_device(_dev);

        imx_ports[dev->id].port.dev = _dev;
        uart_add_one_port(&imx_reg, &imx_ports[dev->id].port);
        dev_set_drvdata(_dev, &imx_ports[dev->id]);
        return 0;
}

static int serial_imx_remove(struct device *_dev)
{
        struct imx_port *sport = dev_get_drvdata(_dev);

        dev_set_drvdata(_dev, NULL);

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

        return 0;
}

static struct device_driver serial_imx_driver = {
        .name           = "imx-uart",
        .bus            = &platform_bus_type,
        .probe          = serial_imx_probe,
        .remove         = serial_imx_remove,

        .suspend        = serial_imx_suspend,
        .resume         = serial_imx_resume,
};

static int __init imx_serial_init(void)
{
        int ret;

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

        imx_init_ports();

        ret = uart_register_driver(&imx_reg);
        if (ret)
                return ret;

        ret = driver_register(&serial_imx_driver);
        if (ret != 0)
                uart_unregister_driver(&imx_reg);

        return 0;
}

static void __exit imx_serial_exit(void)
{
        uart_unregister_driver(&imx_reg);
}

module_init(imx_serial_init);
module_exit(imx_serial_exit);

MODULE_AUTHOR("Sascha Hauer");
MODULE_DESCRIPTION("IMX generic serial port driver");
MODULE_LICENSE("GPL");