cpu/mips/serial.c

/*
 * (INCA) ASC UART support
 */

#include <common.h>
#include <asm/inca-ip.h>
#include "serial.h"

#define SET_BIT(reg, mask)                  reg |= (mask)
#define CLEAR_BIT(reg, mask)                reg &= (~mask)
#define CLEAR_BITS(reg, mask)               CLEAR_BIT(reg, mask)
#define SET_BITS(reg, mask)                 SET_BIT(reg, mask)
#define SET_BITFIELD(reg, mask, off, val)   {reg &= (~mask); reg |= (val << off);}

extern uint incaip_get_fpiclk(void);

static int serial_setopt (void);

/* pointer to ASC register base address */
static volatile incaAsc_t *pAsc = (incaAsc_t *)INCA_IP_ASC;

/******************************************************************************
*
* serial_init - initialize a INCAASC channel
*
* This routine initializes the number of data bits, parity
* and set the selected baud rate. Interrupts are disabled.
* Set the modem control signals if the option is selected.
*
* RETURNS: N/A
*/

int serial_init (void)
{
    /* we have to set PMU.EN13 bit to enable an ASC device*/
    INCAASC_PMU_ENABLE(13);
    
    /* and we have to set CLC register*/
    CLEAR_BIT(pAsc->asc_clc, ASCCLC_DISS);
    SET_BITFIELD(pAsc->asc_clc, ASCCLC_RMCMASK, ASCCLC_RMCOFFSET, 0x0001);
    
    /* initialy we are in async mode */
    pAsc->asc_con = ASCCON_M_8ASYNC;

    /* select input port */
    pAsc->asc_pisel = (CONSOLE_TTY & 0x1);

    /* TXFIFO's filling level */
    SET_BITFIELD(pAsc->asc_txfcon, ASCTXFCON_TXFITLMASK,
                    ASCTXFCON_TXFITLOFF, INCAASC_TXFIFO_FL);
    /* enable TXFIFO */
    SET_BIT(pAsc->asc_txfcon, ASCTXFCON_TXFEN);

    /* RXFIFO's filling level */
    SET_BITFIELD(pAsc->asc_txfcon, ASCRXFCON_RXFITLMASK, 
                    ASCRXFCON_RXFITLOFF, INCAASC_RXFIFO_FL);
    /* enable RXFIFO */
    SET_BIT(pAsc->asc_rxfcon, ASCRXFCON_RXFEN);

    /* enable error signals */
    SET_BIT(pAsc->asc_con, ASCCON_FEN);
    SET_BIT(pAsc->asc_con, ASCCON_OEN);

    /* acknowledge ASC interrupts */
    ASC_INTERRUPTS_CLEAR(INCAASC_IRQ_LINE_ALL);

    /* disable ASC interrupts */
    ASC_INTERRUPTS_DISABLE(INCAASC_IRQ_LINE_ALL);

    /* set FIFOs into the transparent mode */
    SET_BIT(pAsc->asc_txfcon, ASCTXFCON_TXTMEN);
    SET_BIT(pAsc->asc_rxfcon, ASCRXFCON_RXTMEN);

    /* set baud rate */
    serial_setbrg();

    /* set the options */
    serial_setopt();
    
    return 0;
}

void serial_setbrg (void)
{
    ulong      uiReloadValue, fdv;
    ulong      f_ASC;

    f_ASC = incaip_get_fpiclk();

#ifndef INCAASC_USE_FDV
    fdv = 2;
    uiReloadValue = (f_ASC / (fdv * 16 * CONFIG_BAUDRATE)) - 1;
#else 
    fdv = INCAASC_FDV_HIGH_BAUDRATE;
    uiReloadValue = (f_ASC / (8192 * CONFIG_BAUDRATE / fdv)) - 1;
#endif /* INCAASC_USE_FDV */
    
    if ( (uiReloadValue < 0) || (uiReloadValue > 8191) )
    {
#ifndef INCAASC_USE_FDV
        fdv = 3;
        uiReloadValue = (f_ASC / (fdv * 16 * CONFIG_BAUDRATE)) - 1;
#else 
        fdv = INCAASC_FDV_LOW_BAUDRATE;
        uiReloadValue = (f_ASC / (8192 * CONFIG_BAUDRATE / fdv)) - 1;
#endif /* INCAASC_USE_FDV */
        
        if ( (uiReloadValue < 0) || (uiReloadValue > 8191) )
        {
            return;    /* can't impossibly generate that baud rate */
        }
    }

    /* Disable Baud Rate Generator; BG should only be written when R=0 */
    CLEAR_BIT(pAsc->asc_con, ASCCON_R);

#ifndef INCAASC_USE_FDV
    /*
     * Disable Fractional Divider (FDE)
     * Divide clock by reload-value + constant (BRS)
     */
    /* FDE = 0 */
    CLEAR_BIT(pAsc->asc_con, ASCCON_FDE);

    if ( fdv == 2 )
        CLEAR_BIT(pAsc->asc_con, ASCCON_BRS);   /* BRS = 0 */
    else
        SET_BIT(pAsc->asc_con, ASCCON_BRS); /* BRS = 1 */

#else /* INCAASC_USE_FDV */

    /* Enable Fractional Divider */
    SET_BIT(pAsc->asc_con, ASCCON_FDE); /* FDE = 1 */

    /* Set fractional divider value */
    pAsc->asc_fdv = fdv & ASCFDV_VALUE_MASK;

#endif /* INCAASC_USE_FDV */

    /* Set reload value in BG */
    pAsc->asc_bg = uiReloadValue;

    /* Enable Baud Rate Generator */
    SET_BIT(pAsc->asc_con, ASCCON_R);           /* R = 1 */
}

/*******************************************************************************
*
* serial_setopt - set the serial options
*
* Set the channel operating mode to that specified. Following options
* are supported: CREAD, CSIZE, PARENB, and PARODD.
*
* Note, this routine disables the transmitter.  The calling routine
* may have to re-enable it.
*
* RETURNS:
* Returns 0 to indicate success, otherwise -1 is returned
*/

static int serial_setopt (void)
{
    ulong  con;

    switch ( ASC_OPTIONS & ASCOPT_CSIZE )
    {
    /* 7-bit-data */
    case ASCOPT_CS7:
        con = ASCCON_M_7ASYNCPAR;   /* 7-bit-data and parity bit */
        break;

    /* 8-bit-data */
    case ASCOPT_CS8:
        if ( ASC_OPTIONS & ASCOPT_PARENB )
            con = ASCCON_M_8ASYNCPAR;   /* 8-bit-data and parity bit */
        else
            con = ASCCON_M_8ASYNC;      /* 8-bit-data no parity */
        break;
    
    /* 
     *  only 7 and 8-bit frames are supported
     *  if we don't use IOCTL extensions 
     */
    default:
        return -1;
    }

    if ( ASC_OPTIONS & ASCOPT_STOPB )
        SET_BIT(con, ASCCON_STP);       /* 2 stop bits */
    else
        CLEAR_BIT(con, ASCCON_STP);     /* 1 stop bit */

    if ( ASC_OPTIONS & ASCOPT_PARENB )
        SET_BIT(con, ASCCON_PEN);           /* enable parity checking */    
    else
        CLEAR_BIT(con, ASCCON_PEN);         /* disable parity checking */
    
    if ( ASC_OPTIONS & ASCOPT_PARODD )
        SET_BIT(con, ASCCON_ODD);       /* odd parity */
    else
        CLEAR_BIT(con, ASCCON_ODD);     /* even parity */

    if ( ASC_OPTIONS & ASCOPT_CREAD )
        SET_BIT(pAsc->asc_whbcon, ASCWHBCON_SETREN); /* Receiver enable */

    pAsc->asc_con |= con;

    return 0;
}

void serial_putc (const char c)
{
    uint txFl = 0;

    if (c == '\n') serial_putc ('\r');

    /* check do we have a free space in the TX FIFO */
    /* get current filling level */
    do
    {
	txFl = ( pAsc->asc_fstat & ASCFSTAT_TXFFLMASK ) >> ASCFSTAT_TXFFLOFF;
    }
    while ( txFl == INCAASC_TXFIFO_FULL );

    pAsc->asc_tbuf = c; /* write char to Transmit Buffer Register */
    /* check for errors */
    if ( pAsc->asc_con & ASCCON_OE )
    {
        SET_BIT(pAsc->asc_whbcon, ASCWHBCON_CLROE);
        return;
    }
}

void serial_puts (const char *s)
{
    while (*s)
    {
	serial_putc (*s++);
    }
}

int serial_getc (void)
{
    ulong symbol_mask;
    char c;

    while (!serial_tstc());

    symbol_mask =
	((ASC_OPTIONS & ASCOPT_CSIZE) == ASCOPT_CS7) ? (0x7f) : (0xff);
    
    c = (char)(pAsc->asc_rbuf & symbol_mask);

    return c;
}

int serial_tstc (void)
{
    int res = 1;

    if ( (pAsc->asc_fstat & ASCFSTAT_RXFFLMASK) == 0 )
    {
        res = 0;
    }
    else if ( pAsc->asc_con & ASCCON_FE )
    {
        SET_BIT(pAsc->asc_whbcon, ASCWHBCON_CLRFE);
        res = 0;
    }
    else if ( pAsc->asc_con & ASCCON_PE )
    {
        SET_BIT(pAsc->asc_whbcon, ASCWHBCON_CLRPE);
        res = 0;
    }
    else if ( pAsc->asc_con & ASCCON_OE )
    {
        SET_BIT(pAsc->asc_whbcon, ASCWHBCON_CLROE);
        res = 0;
    }

    return res;
}