uart.c

文件内包含了nuclues的内核代码和针对Power PC的编译器。需要用VirtNet生成一个虚拟网卡才可使用

CHAR UART_Get_Char(UNSIGNED smc)
{
    CHAR           ch;
    CHAR           i;

    if ((uart[smc].read != uart[smc].write) ||
            uart[smc].buf_status == BUF_FULL)
    {
        i = uart[smc].read;
        ch = uart[smc].buffer[i];
        uart[smc].read = ++(uart[smc].read) % BUF_LEN;
        uart[smc].buf_status = BUF_NOT_FULL;
    }
    else
        ch = BUF_EMPTY;

    return ch;
}

/****************************************************************************/
/* FUNCTION                                                                 */
/*                                                                          */
/*    UART_Put_Char                                                         */
/*                                                                          */
/* DESCRIPTION                                                              */
/*                                                                          */
/*    This writes a character out to the serial port.                       */
/*                                                                          */
/* CALLED BY                                                                */
/*                                                                          */
/*    NU_Xmit_Packet                                                        */
/*    MDM_Control_String                                                    */
/*                                                                          */
/* CALLS                                                                    */
/*                                                                          */
/*    None                                                                  */
/*                                                                          */
/* INPUTS                                                                   */
/*                                                                          */
/*    UNSIGNED    :   The SMC port to be written to                         */
/*    CHAR        :   Character to to be written to the serial port.        */
/*                                                                          */
/* OUTPUTS                                                                  */
/*                                                                          */
/*    none                                                                  */
/*                                                                          */
/* HISTORY                                                                  */
/*                                                                          */
/*        NAME             DATE                  REMARKS                    */
/*                                                                          */
/*      B. Sellew        12/24/97         Created Initial version.          */
/*                                                                          */
/****************************************************************************/
VOID UART_Put_Char(UNSIGNED smc, CHAR ch)
{
    PDA    *immr = (PDA *) (Get_IMMR() & 0xffff0000);  
    BD     *tbd = (BD *) immr->udata_bd;      

    if (smc == SMC1)
        tbd += (RX_BUFFERS + tbd_idx[smc]);
    else 
        tbd += ((RX_BUFFERS * 2) + TX_BUFFERS + tbd_idx[smc]);

    /* write the character */
    *(tbd->addr) = ch; 
    tbd->length = 1;
    tbd->status |= 0x8000;

    /* wait until the character has been sent */
    while (tbd->status & 0x8000);

    /* increment current Tx BD pointer */
    tbd_idx[smc] = ++(tbd_idx[smc]) % TX_BUFFERS;
}

/****************************************************************************/
/* FUNCTION                                                                 */
/*                                                                          */
/*    UART_Put_String                                                       */
/*                                                                          */
/* DESCRIPTION                                                              */
/*                                                                          */
/*    This writes a null-terminated string out to the serial port.          */
/*                                                                          */
/* CALLED BY                                                                */
/*                                                                          */
/*    Application                                                           */
/*                                                                          */
/* CALLS                                                                    */
/*                                                                          */
/*    UART_Put_Char                                                         */
/*                                                                          */
/* INPUTS                                                                   */
/*                                                                          */
/*    UNSIGNED    :   The SMC port to be written to                         */
/*    CHAR        :   Character to be written to the serial port.           */
/*                                                                          */
/* OUTPUTS                                                                  */
/*                                                                          */
/*    none                                                                  */
/*                                                                          */
/* HISTORY                                                                  */
/*                                                                          */
/*        NAME             DATE                  REMARKS                    */
/*                                                                          */
/*      B. Sellew        12/24/97         Created Initial version.          */
/*                                                                          */
/****************************************************************************/
VOID UART_Put_String(UNSIGNED smc, CHAR *str)
{
    for (; *str != 0; str++)
        UART_Put_Char(smc, *str);
}
/****************************************************************************/
/* FUNCTION                                                                 */
/*                                                                          */
/*    UART_Set_Baud_Rate                                                    */
/*                                                                          */
/* DESCRIPTION                                                              */
/*                                                                          */
/*    This function sets the baud rate control register to the input baud   */
/*    rate.                                                                 */
/*                                                                          */
/* CALLED BY                                                                */
/*                                                                          */
/*    MDM_Hangup                                                            */
/*                                                                          */
/* CALLS                                                                    */
/*                                                                          */
/*    None                                                                  */
/*                                                                          */
/* INPUTS                                                                   */
/*                                                                          */
/*    UNSINGED      :  The SMC port to configure                            */
/*    UNSINGED      :  Baud rate                                            */
/*                                                                          */
/* OUTPUTS                                                                  */
/*                                                                          */
/*    None                                                                  */
/*                                                                          */
/* HISTORY                                                                  */
/*                                                                          */
/*        NAME             DATE                  REMARKS                    */
/*                                                                          */
/*      B. Sellew        01/02/98         Created Initial version.          */
/*                                                                          */
/****************************************************************************/
VOID UART_Set_Baud_Rate(UNSIGNED smc, UNSIGNED baud_rate)
{
    PDA            *immr = (PDA *)(Get_IMMR() & 0xffff0000);
    UNSIGNED       br_div;

    /* calculate the baud rate divisor */
    br_div = (SYSCLK / (16 * baud_rate)) - 1;

    /* if the divisor is too large, prescale by 16 */
    if (br_div >=  4096)
    {
        br_div = br_div / 16;
        br_div = br_div << 1;
        br_div |= 1;
    }
    else
        br_div = br_div << 1;

    /* set the baud control register */
    if (smc == SMC1)
        immr->brgc1 = br_div | 0x10000;
    else
        immr->brgc2 = br_div | 0x10000;

} /* UART_Set_Baud_Rate */

/****************************************************************************/
/* FUNCTION                                                                 */
/*                                                                          */
/*    UART_Change_Communication_Mode                                        */
/*                                                                          */
/* DESCRIPTION                                                              */
/*                                                                          */
/*    This function switches the serial port between terminal mode and      */
/*    PPP mode.  The Mode affects where incoming characters are directed.   */
/*                                                                          */
/* CALLED BY                                                                */
/*                                                                          */
/*    MDM_Change_Communication_Mode                                         */
/*                                                                          */
/* CALLS                                                                    */
/*                                                                          */
/*    none                                                                  */
/*                                                                          */
/* INPUTS                                                                   */
/*                                                                          */
/*    INT      :  The mode of operation desired.                            */
/*                                                                          */
/* OUTPUTS                                                                  */
/*                                                                          */
/*    none                                                                  */
/*                                                                          */
/* HISTORY                                                                  */
/*                                                                          */
/*        NAME             DATE                  REMARKS                    */
/*                                                                          */
/*      B. Sellew        01/02/98         Created Initial version.          */
/*                                                                          */
/****************************************************************************/
VOID UART_Change_Communication_Mode(INT mode)
{

    UART_Communication_Mode = mode;

} /* UART_Change_Communication_Mode */

Get_IMMR ()
{
    asm("    mfspr   r3, 638");
}