mcf.c

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/****************************************************************************/

/*
 *  mcf.c -- Freescale ColdFire UART driver
 *
 *  (C) Copyright 2003-2007, Greg Ungerer <[email protected]>
 *
 * 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.
 */

/****************************************************************************/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/io.h>
#include <asm/coldfire.h>
#include <asm/mcfsim.h>
#include <asm/mcfuart.h>
#include <asm/nettel.h>

/****************************************************************************/

/*
 *  Some boards implement the DTR/DCD lines using GPIO lines, most
 *  don't. Dummy out the access macros for those that don't. Those
 *  that do should define these macros somewhere in there board
 *  specific inlude files.
 */
#if !defined(mcf_getppdcd)
#define mcf_getppdcd(p)     (1)
#endif
#if !defined(mcf_getppdtr)
#define mcf_getppdtr(p)     (1)
#endif
#if !defined(mcf_setppdtr)
#define mcf_setppdtr(p, v)  do { } while (0)
#endif

/****************************************************************************/

/*
 *  Local per-uart structure.
 */
struct mcf_uart {
    struct uart_port    port;
    unsigned int        sigs;       /* Local copy of line sigs */
    unsigned char       imr;        /* Local IMR mirror */
};

/****************************************************************************/

static unsigned int mcf_tx_empty(struct uart_port *port)
{
    return (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXEMPTY) ?
        TIOCSER_TEMT : 0;
}

/****************************************************************************/

static unsigned int mcf_get_mctrl(struct uart_port *port)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
    unsigned int sigs;

    sigs = (readb(port->membase + MCFUART_UIPR) & MCFUART_UIPR_CTS) ?
        0 : TIOCM_CTS;
    sigs |= (pp->sigs & TIOCM_RTS);
    sigs |= (mcf_getppdcd(port->line) ? TIOCM_CD : 0);
    sigs |= (mcf_getppdtr(port->line) ? TIOCM_DTR : 0);

    return sigs;
}

/****************************************************************************/

static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

    pp->sigs = sigs;
    mcf_setppdtr(port->line, (sigs & TIOCM_DTR));
    if (sigs & TIOCM_RTS)
        writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
    else
        writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP0);
}

/****************************************************************************/

static void mcf_start_tx(struct uart_port *port)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

    pp->imr |= MCFUART_UIR_TXREADY;
    writeb(pp->imr, port->membase + MCFUART_UIMR);
}

/****************************************************************************/

static void mcf_stop_tx(struct uart_port *port)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

    pp->imr &= ~MCFUART_UIR_TXREADY;
    writeb(pp->imr, port->membase + MCFUART_UIMR);
}

/****************************************************************************/

static void mcf_stop_rx(struct uart_port *port)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);

    pp->imr &= ~MCFUART_UIR_RXREADY;
    writeb(pp->imr, port->membase + MCFUART_UIMR);
}

/****************************************************************************/

static void mcf_break_ctl(struct uart_port *port, int break_state)
{
    unsigned long flags;

    spin_lock_irqsave(&port->lock, flags);
    if (break_state == -1)
        writeb(MCFUART_UCR_CMDBREAKSTART, port->membase + MCFUART_UCR);
    else
        writeb(MCFUART_UCR_CMDBREAKSTOP, port->membase + MCFUART_UCR);
    spin_unlock_irqrestore(&port->lock, flags);
}

/****************************************************************************/

static void mcf_enable_ms(struct uart_port *port)
{
}

/****************************************************************************/

static int mcf_startup(struct uart_port *port)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
    unsigned long flags;

    spin_lock_irqsave(&port->lock, flags);

    /* Reset UART, get it into known state... */
    writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
    writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);

    /* Enable the UART transmitter and receiver */
    writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
        port->membase + MCFUART_UCR);

    /* Enable RX interrupts now */
    pp->imr = MCFUART_UIR_RXREADY;
    writeb(pp->imr, port->membase + MCFUART_UIMR);

    spin_unlock_irqrestore(&port->lock, flags);

    return 0;
}

/****************************************************************************/

static void mcf_shutdown(struct uart_port *port)
{
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
    unsigned long flags;

    spin_lock_irqsave(&port->lock, flags);

    /* Disable all interrupts now */
    pp->imr = 0;
    writeb(pp->imr, port->membase + MCFUART_UIMR);

    /* Disable UART transmitter and receiver */
    writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
    writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);

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

/****************************************************************************/

static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
    struct ktermios *old)
{
    unsigned long flags;
    unsigned int baud, baudclk;
#if defined(CONFIG_M5272)
    unsigned int baudfr;
#endif
    unsigned char mr1, mr2;

    baud = uart_get_baud_rate(port, termios, old, 0, 230400);
#if defined(CONFIG_M5272)
    baudclk = (MCF_BUSCLK / baud) / 32;
    baudfr = (((MCF_BUSCLK / baud) + 1) / 2) % 16;
#else
    baudclk = ((MCF_BUSCLK / baud) + 16) / 32;
#endif

    mr1 = MCFUART_MR1_RXIRQRDY | MCFUART_MR1_RXERRCHAR;
    mr2 = 0;

    switch (termios->c_cflag & CSIZE) {
    case CS5: mr1 |= MCFUART_MR1_CS5; break;
    case CS6: mr1 |= MCFUART_MR1_CS6; break;
    case CS7: mr1 |= MCFUART_MR1_CS7; break;
    case CS8:
    default:  mr1 |= MCFUART_MR1_CS8; break;
    }

    if (termios->c_cflag & PARENB) {
        if (termios->c_cflag & CMSPAR) {
            if (termios->c_cflag & PARODD)
                mr1 |= MCFUART_MR1_PARITYMARK;
            else
                mr1 |= MCFUART_MR1_PARITYSPACE;
        } else {
            if (termios->c_cflag & PARODD)
                mr1 |= MCFUART_MR1_PARITYODD;
            else
                mr1 |= MCFUART_MR1_PARITYEVEN;
        }
    } else {
        mr1 |= MCFUART_MR1_PARITYNONE;
    }

    if (termios->c_cflag & CSTOPB)
        mr2 |= MCFUART_MR2_STOP2;
    else
        mr2 |= MCFUART_MR2_STOP1;

    if (termios->c_cflag & CRTSCTS) {
        mr1 |= MCFUART_MR1_RXRTS;
        mr2 |= MCFUART_MR2_TXCTS;
    }

    spin_lock_irqsave(&port->lock, flags);
    uart_update_timeout(port, termios->c_cflag, baud);
    writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
    writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
    writeb(MCFUART_UCR_CMDRESETMRPTR, port->membase + MCFUART_UCR);
    writeb(mr1, port->membase + MCFUART_UMR);
    writeb(mr2, port->membase + MCFUART_UMR);
    writeb((baudclk & 0xff00) >> 8, port->membase + MCFUART_UBG1);
    writeb((baudclk & 0xff), port->membase + MCFUART_UBG2);
#if defined(CONFIG_M5272)
    writeb((baudfr & 0x0f), port->membase + MCFUART_UFPD);
#endif
    writeb(MCFUART_UCSR_RXCLKTIMER | MCFUART_UCSR_TXCLKTIMER,
        port->membase + MCFUART_UCSR);
    writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
        port->membase + MCFUART_UCR);
    spin_unlock_irqrestore(&port->lock, flags);
}

/****************************************************************************/

static void mcf_rx_chars(struct mcf_uart *pp)
{
    struct uart_port *port = &pp->port;
    unsigned char status, ch, flag;

    while ((status = readb(port->membase + MCFUART_USR)) & MCFUART_USR_RXREADY) {
        ch = readb(port->membase + MCFUART_URB);
        flag = TTY_NORMAL;
        port->icount.rx++;

        if (status & MCFUART_USR_RXERR) {
            writeb(MCFUART_UCR_CMDRESETERR,
                port->membase + MCFUART_UCR);

            if (status & MCFUART_USR_RXBREAK) {
                port->icount.brk++;
                if (uart_handle_break(port))
                    continue;
            } else if (status & MCFUART_USR_RXPARITY) {
                port->icount.parity++;
            } else if (status & MCFUART_USR_RXOVERRUN) {
                port->icount.overrun++;
            } else if (status & MCFUART_USR_RXFRAMING) {
                port->icount.frame++;
            }

            status &= port->read_status_mask;

            if (status & MCFUART_USR_RXBREAK)
                flag = TTY_BREAK;
            else if (status & MCFUART_USR_RXPARITY)
                flag = TTY_PARITY;
            else if (status & MCFUART_USR_RXFRAMING)
                flag = TTY_FRAME;
        }

        if (uart_handle_sysrq_char(port, ch))
            continue;
        uart_insert_char(port, status, MCFUART_USR_RXOVERRUN, ch, flag);
    }

    tty_flip_buffer_push(port->state->port.tty);
}

/****************************************************************************/

static void mcf_tx_chars(struct mcf_uart *pp)
{
    struct uart_port *port = &pp->port;
    struct circ_buf *xmit = &port->state->xmit;

    if (port->x_char) {
        /* Send special char - probably flow control */
        writeb(port->x_char, port->membase + MCFUART_UTB);
        port->x_char = 0;
        port->icount.tx++;
        return;
    }

    while (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY) {
        if (xmit->head == xmit->tail)
            break;
        writeb(xmit->buf[xmit->tail], port->membase + MCFUART_UTB);
        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE -1);
        port->icount.tx++;
    }

    if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
        uart_write_wakeup(port);

    if (xmit->head == xmit->tail) {
        pp->imr &= ~MCFUART_UIR_TXREADY;
        writeb(pp->imr, port->membase + MCFUART_UIMR);
    }
}

/****************************************************************************/

static irqreturn_t mcf_interrupt(int irq, void *data)
{
    struct uart_port *port = data;
    struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
    unsigned int isr;
    irqreturn_t ret = IRQ_NONE;

    isr = readb(port->membase + MCFUART_UISR) & pp->imr;

    spin_lock(&port->lock);
    if (isr & MCFUART_UIR_RXREADY) {
        mcf_rx_chars(pp);
        ret = IRQ_HANDLED;
    }
    if (isr & MCFUART_UIR_TXREADY) {
        mcf_tx_chars(pp);
        ret = IRQ_HANDLED;
    }
    spin_unlock(&port->lock);

    return ret;
}

/****************************************************************************/

static void mcf_config_port(struct uart_port *port, int flags)
{
    port->type = PORT_MCF;
    port->fifosize = MCFUART_TXFIFOSIZE;

    /* Clear mask, so no surprise interrupts. */
    writeb(0, port->membase + MCFUART_UIMR);

    if (request_irq(port->irq, mcf_interrupt, 0, "UART", port))
        printk(KERN_ERR "MCF: unable to attach ColdFire UART %d "
            "interrupt vector=%d\n", port->line, port->irq);
}

/****************************************************************************/

static const char *mcf_type(struct uart_port *port)
{
    return (port->type == PORT_MCF) ? "ColdFire UART" : NULL;
}

/****************************************************************************/

static int mcf_request_port(struct uart_port *port)
{
    /* UARTs always present */
    return 0;
}

/****************************************************************************/

static void mcf_release_port(struct uart_port *port)
{
    /* Nothing to release... */
}

/****************************************************************************/

static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)
{
    if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_MCF))
        return -EINVAL;
    return 0;
}

/****************************************************************************/

/*
 *  Define the basic serial functions we support.
 */
static const struct uart_ops mcf_uart_ops = {
    .tx_empty   = mcf_tx_empty,
    .get_mctrl  = mcf_get_mctrl,
    .set_mctrl  = mcf_set_mctrl,
    .start_tx   = mcf_start_tx,
    .stop_tx    = mcf_stop_tx,
    .stop_rx    = mcf_stop_rx,
    .enable_ms  = mcf_enable_ms,
    .break_ctl  = mcf_break_ctl,
    .startup    = mcf_startup,
    .shutdown   = mcf_shutdown,
    .set_termios    = mcf_set_termios,
    .type       = mcf_type,
    .request_port   = mcf_request_port,
    .release_port   = mcf_release_port,
    .config_port    = mcf_config_port,
    .verify_port    = mcf_verify_port,
};

static struct mcf_uart mcf_ports[4];

#define MCF_MAXPORTS    ARRAY_SIZE(mcf_ports)

/****************************************************************************/
#if defined(CONFIG_SERIAL_MCF_CONSOLE)
/****************************************************************************/

int __init early_mcf_setup(struct mcf_platform_uart *platp)
{
    struct uart_port *port;
    int i;

    for (i = 0; ((i < MCF_MAXPORTS) && (platp[i].mapbase)); i++) {
        port = &mcf_ports[i].port;

        port->line = i;
        port->type = PORT_MCF;
        port->mapbase = platp[i].mapbase;
        port->membase = (platp[i].membase) ? platp[i].membase :
            (unsigned char __iomem *) port->mapbase;
        port->iotype = SERIAL_IO_MEM;
        port->irq = platp[i].irq;
        port->uartclk = MCF_BUSCLK;
        port->flags = ASYNC_BOOT_AUTOCONF;
        port->ops = &mcf_uart_ops;
    }

    return 0;
}

/****************************************************************************/

static void mcf_console_putc(struct console *co, const char c)
{
    struct uart_port *port = &(mcf_ports + co->index)->port;
    int i;

    for (i = 0; (i < 0x10000); i++) {
        if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
            break;
    }
    writeb(c, port->membase + MCFUART_UTB);
    for (i = 0; (i < 0x10000); i++) {
        if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
            break;
    }
}

/****************************************************************************/

static void mcf_console_write(struct console *co, const char *s, unsigned int count)
{
    for (; (count); count--, s++) {
        mcf_console_putc(co, *s);
        if (*s == '\n')
            mcf_console_putc(co, '\r');
    }
}

/****************************************************************************/

static int __init mcf_console_setup(struct console *co, char *options)
{
    struct uart_port *port;
    int baud = CONFIG_SERIAL_MCF_BAUDRATE;
    int bits = 8;
    int parity = 'n';
    int flow = 'n';

    if ((co->index < 0) || (co->index >= MCF_MAXPORTS))
        co->index = 0;
    port = &mcf_ports[co->index].port;
    if (port->membase == 0)
        return -ENODEV;

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

    return uart_set_options(port, co, baud, parity, bits, flow);
}

/****************************************************************************/

static struct uart_driver mcf_driver;

static struct console mcf_console = {
    .name       = "ttyS",
    .write      = mcf_console_write,
    .device     = uart_console_device,
    .setup      = mcf_console_setup,
    .flags      = CON_PRINTBUFFER,
    .index      = -1,
    .data       = &mcf_driver,
};

static int __init mcf_console_init(void)
{
    register_console(&mcf_console);
    return 0;
}

console_initcall(mcf_console_init);

#define MCF_CONSOLE &mcf_console

/****************************************************************************/
#else
/****************************************************************************/

#define MCF_CONSOLE NULL

/****************************************************************************/
#endif /* CONFIG_MCF_CONSOLE */
/****************************************************************************/

/*
 *  Define the mcf UART driver structure.
 */
static struct uart_driver mcf_driver = {
    .owner      = THIS_MODULE,
    .driver_name    = "mcf",
    .dev_name   = "ttyS",
    .major      = TTY_MAJOR,
    .minor      = 64,
    .nr     = MCF_MAXPORTS,
    .cons       = MCF_CONSOLE,
};

/****************************************************************************/

static int __devinit mcf_probe(struct platform_device *pdev)
{
    struct mcf_platform_uart *platp = pdev->dev.platform_data;
    struct uart_port *port;
    int i;

    for (i = 0; ((i < MCF_MAXPORTS) && (platp[i].mapbase)); i++) {
        port = &mcf_ports[i].port;

        port->line = i;
        port->type = PORT_MCF;
        port->mapbase = platp[i].mapbase;
        port->membase = (platp[i].membase) ? platp[i].membase :
            (unsigned char __iomem *) platp[i].mapbase;
        port->iotype = SERIAL_IO_MEM;
        port->irq = platp[i].irq;
        port->uartclk = MCF_BUSCLK;
        port->ops = &mcf_uart_ops;
        port->flags = ASYNC_BOOT_AUTOCONF;

        uart_add_one_port(&mcf_driver, port);
    }

    return 0;
}

/****************************************************************************/

static int __devexit mcf_remove(struct platform_device *pdev)
{
    struct uart_port *port;
    int i;

    for (i = 0; (i < MCF_MAXPORTS); i++) {
        port = &mcf_ports[i].port;
        if (port)
            uart_remove_one_port(&mcf_driver, port);
    }

    return 0;
}

/****************************************************************************/

static struct platform_driver mcf_platform_driver = {
    .probe      = mcf_probe,
    .remove     = __devexit_p(mcf_remove),
    .driver     = {
        .name   = "mcfuart",
        .owner  = THIS_MODULE,
    },
};

/****************************************************************************/

static int __init mcf_init(void)
{
    int rc;

    printk("ColdFire internal UART serial driver\n");

    rc = uart_register_driver(&mcf_driver);
    if (rc)
        return rc;
    rc = platform_driver_register(&mcf_platform_driver);
    if (rc)
        return rc;
    return 0;
}

/****************************************************************************/

static void __exit mcf_exit(void)
{
    platform_driver_unregister(&mcf_platform_driver);
    uart_unregister_driver(&mcf_driver);
}

/****************************************************************************/

module_init(mcf_init);
module_exit(mcf_exit);

MODULE_AUTHOR("Greg Ungerer <[email protected]>");
MODULE_DESCRIPTION("Freescale ColdFire UART driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mcfuart");

/****************************************************************************/