uart_403.c

完整的Bell实验室的嵌入式文件系统TFS

/*  uart_403.c:
 *  This file contains the PPC403 generic serial port driver.
 *
 *  General notice:
 *  This code is part of a boot-monitor package developed as a generic base
 *  platform for embedded system designs.  As such, it is likely to be
 *  distributed to various projects beyond the control of the original
 *  author.  Please notify the author of any enhancements made or bugs found
 *  so that all may benefit from the changes.  In addition, notification back
 *  to the author will allow the new user to pick up changes that may have
 *  been made by other users after this version of the code was distributed.
 *
 *  Note1: the majority of this code was edited with 4-space tabs.
 *  Note2: as more and more contributions are accepted, the term "author"
 *         is becoming a mis-representation of credit.
 *
 *  Original author:    Ed Sutter
 *  Email:              [e-mail]
 *  Phone:              908-582-2351
 */
#include "config.h"
#include "cpuio.h"
#include "genlib.h"
#include "ether.h"
#include "stddefs.h"
#include "cpu_403.h"

int ConsoleBaudRate;
int (*remoterawon)(), (*remoterawoff)();
int (*remoteputchar)(), (*remotegetchar)(), (*remotegotachar)();

/* InitUART():
    Fed the baudrate.
*/
int
Init403UART(int baud)
{
    int divisor, brdl, brdh;

    if (baud == 0)
        baud = ConsoleBaudRate;

    /* Keep track of the last baud rate, so that it can be used if the */
    /* incoming baudrate is NULL. */
    ConsoleBaudRate = baud;

    /* Compute Baud Rate Divisor value */
    divisor = (MON_CPU_CLOCK/(16*baud)) - 1;
    brdl = divisor & 0xff;
    brdh = divisor / 0x100;

    /* Initialize 403GCX UART: */
    CPU_SPU_SPRC = 0;           /* Disable xmitter and receiver */
    CPU_SPU_SPTC = 0;

    CPU_SPU_SPLS = 0xf8;        /* Clear bits in line status reg */

    CPU_SPU_BRDL = brdl;        /* Set baud rate divisor lsb    */
    CPU_SPU_BRDH = brdh;        /* Set baud rate divisor msb    */

    CPU_SPU_SPCTL = 0x38;       /* Set DTR & RTS, 8 bits, no parity */

    CPU_SPU_SPRC = 0x80;        /* Enable receiver      */
    CPU_SPU_SPTC = 0x80;        /* Enable transmitter       */

    CPU_SPU_SPHS = 0xc0;        /* Clear bits in handshake reg  */

    InitRemoteIO();

    return(0);
}

/* rputchar():
    Raw put char.
*/
int
rputchar403(char c)
{
    /* First check to see if the default rputchar() function has */
    /* been overridden... */
    if (remoteputchar) {
        remoteputchar(c);
        return((int)c);
    }

    while ((CPU_SPU_SPLS & CPU_SPLS_TBR) == 0);
    CPU_SPU_SPTB = c;

#if INCLUDE_ETHERNET
    SendIPMonChar(c,0);
#endif

    return((int)c);
}

int
putchar403(char c)
{
    if (c == '\n')
        rputchar403('\r');
    return(rputchar403(c));
}

/* gotachar():
    Return 0 if no char is avaialable at UART rcv fifo; else 1.
    Do NOT pull character out of fifo, just return status. 
*/
int
gotachar403()
{
    if (remotegotachar)
        return(remotegotachar());

    if ((CPU_SPU_SPLS & CPU_SPLS_RBR) != 0)
        return(1);
    return(0);
}

/* getchar():
    Block on the Uart's status until a byte is available in the 
    receive buffer, then return with it.
*/
int 
getchar403()
{
    char    c;

    /* First check to see if the default getchar() function has */
    /* been overridden... */
    if (remotegetchar)
        return(remotegetchar());
    
    while(!gotachar403()) {
#if INCLUDE_ETHERNET
        pollethernet();
#endif
    }
    c = CPU_SPU_SPRB;

    return((int)c);
}