source: xtideuniversalbios/trunk/Serial_Server/library/Process.cpp @ 233

//======================================================================
//
// Project:     XTIDE Universal BIOS, Serial Port Server
//
// File:        process.cpp - Processes commands received over the serial port
//

#include "library.h"
#include <memory.h>
#include <string.h>
#include <stdio.h>

union _buff {
    struct {
        unsigned char command;
        unsigned char driveAndHead;
        unsigned char count;
        unsigned char sector;
        unsigned short cylinder;
    } chs;
    struct {
        unsigned char command;
        unsigned char bits24;
        unsigned char count;
        unsigned char bits00;
        unsigned char bits08;
        unsigned char bits16;
    } lba;
    struct {
        unsigned char command;
        unsigned char driveAndHead;
        unsigned char count;
        unsigned char scan;
        unsigned char port;
        unsigned char baud;
    } inquire;
    unsigned char b[514];
    unsigned short w[257];
} buff;

#define SERIAL_COMMAND_HEADER 0xa0

#define SERIAL_COMMAND_WRITE 1
#define SERIAL_COMMAND_READWRITE 2
#define SERIAL_COMMAND_RWMASK 3
#define SERIAL_COMMAND_INQUIRE 0

#define SERIAL_COMMAND_MASK 0xe3
#define SERIAL_COMMAND_HEADERMASK 0xe0

#define ATA_COMMAND_LBA 0x40
#define ATA_COMMAND_HEADMASK 0xf

#define ATA_DriveAndHead_Drive 0x10

void logBuff( char *message, unsigned long buffoffset, unsigned long readto, int verboseLevel )
{
    char logBuff[ 514*9 + 10 ];
    int logCount;

    if( verboseLevel == 5 || (verboseLevel >= 3 && buffoffset == readto) )
    {
        if( verboseLevel == 3 && buffoffset > 11 )
            logCount = 11;
        else
            logCount = buffoffset;

        for( int t = 0; t < logCount; t++ )
            sprintf( &logBuff[t*9], "[%3d:%02x] ", t, buff.b[t] );
        if( logCount != buffoffset )
            sprintf( &logBuff[logCount*9], "... " );

        log( 3, "%s%s", message, logBuff );
    }
}

void processRequests( SerialAccess *serial, Image *image0, Image *image1, int timeoutEnabled, int verboseLevel )
{
    unsigned char workCommand;
    int workOffset, workCount;

    unsigned long mylba;
    unsigned long readto;
    unsigned long buffoffset;
    unsigned long lasttick;
    unsigned short crc;
    unsigned long GetTime_Timeout_Local;
    unsigned long len;
    Image *img;
    unsigned long cyl, sect, head;
    unsigned long perfTimer;
    unsigned char lastScan;

    GetTime_Timeout_Local = GetTime_Timeout();

    buffoffset = 0;
    readto = 0;
    workCount = workOffset = workCommand = 0;
    lastScan = 0;

    lasttick = GetTime();

    while( (len = serial->readCharacters( &buff.b[buffoffset], (readto ? readto-buffoffset : 1) )) )
    {
        buffoffset += len;

        //
        // For debugging, look at the incoming packet
        //
        if( verboseLevel >= 3 )
            logBuff( "    Received: ", buffoffset, readto, verboseLevel );

        if( timeoutEnabled && readto && GetTime() > lasttick + GetTime_Timeout_Local )
        {
            log( 1, "Timeout waiting on data from client, aborting previous command" );

            workCount = workOffset = workCommand = 0;
            readto = 0;

            if( len <= 8 && (buff.b[buffoffset-len] & SERIAL_COMMAND_HEADERMASK) == SERIAL_COMMAND_HEADER )
            {
                // assume that we are at the front of a new command
                //
                memcpy( &buff.b[0], &buff.b[buffoffset-len], len );
                buffoffset = len;
                readto = 8;
                // fall through to normal processing
            }
            else if( len == 1 )
            {
                // one new character, treat it like any other new character received, discarding the buffer
                //
                buff.b[0] = buff.b[buffoffset-1];
                buffoffset = 1;
                // fall through to normal processing
            }
            else
            {
                // discard even the newly received data and start listening anew
                //
                buffoffset = 0;
                continue;
            }
        }

        lasttick = GetTime();

        // 
        // No work currently to do, look at each character as they come in...
        //
        if( !readto )
        {
            if( (buff.b[0] & SERIAL_COMMAND_HEADERMASK) == SERIAL_COMMAND_HEADER )
            {
                //
                // Found our command header byte to start a commnad sequence, read the next 7 and evaluate
                //
                readto = 8;
                continue;
            }
            else
            {
                //
                // Spurious characters, discard
                //
                if( verboseLevel >= 2 )
                {
                    if( buff.b[0] >= 0x20 && buff.b[0] <= 0x7e )
                        log( 2, "Spurious: [%d:%c]", buff.b[0], buff.b[0] );
                    else
                        log( 2, "Spurious: [%d]", buff.b[0] );
                }
                buffoffset = 0;
                continue;
            }
        }

        //
        // Partial packet received, keep reading...
        //
        if( readto && buffoffset < readto )
            continue;

        //
        // Read 512 bytes from serial port, only one command reads that many characters: Write Sector
        //
        if( buffoffset == readto && readto == 514 )
        {
            buffoffset = readto = 0;
            if( (crc = checksum( &buff.w[0], 256 )) != buff.w[256] )
            {
                log( 0, "Bad Write Sector Checksum" );
                continue;
            }

            if( img->readOnly )
            {
                log( 1, "Attempt to write to read-only image" );
                continue;
            }

            img->seekSector( mylba + workOffset );
            img->writeSector( &buff.w[0] );

            //
            // Echo back the CRC
            //
            if( !serial->writeCharacters( &buff.w[256], 2 ) )
                break;

            workOffset++;
            workCount--;

            if( workCount )
                readto = 1;           // looking for continuation ACK
        }

        //
        // 8 byte command received, or a continuation of the previous command
        //
        else if( (buffoffset == readto && readto == 8) ||
                 (buffoffset == readto && readto == 1 && workCount) )
        {
            buffoffset = readto = 0;
            if( workCount )
            {
                if( verboseLevel > 1 )
                    log( 2, "    Continuation: Offset=%u, Checksum=%04x", workOffset-1, buff.w[256] );

                //
                // Continuation...
                //
                if( buff.b[0] != (workCount-0) )
                {
                    log( 0, "Continue Fault: Received=%d, Expected=%d", buff.b[0], workCount );
                    workCount = 0;
                    continue;
                }
            }
            else
            {
                //
                // New Command...
                //
                if( (crc = checksum( &buff.w[0], 3 )) != buff.w[3] )
                {
                    log( 0, "Bad Command Checksum: %02x %02x %02x %02x %02x %02x %02x %02x, Checksum=%04x",
                         buff.b[0], buff.b[1], buff.b[2], buff.b[3], buff.b[4], buff.b[5], buff.b[6], buff.b[7], crc);
                    continue;
                }

                img = (buff.inquire.driveAndHead & ATA_DriveAndHead_Drive) ? image1 : image0;

                workCommand = buff.chs.command & SERIAL_COMMAND_RWMASK;

                if( (workCommand != SERIAL_COMMAND_INQUIRE) && (buff.chs.driveAndHead & ATA_COMMAND_LBA) )
                {
                    mylba = ((((unsigned long) buff.lba.bits24) & ATA_COMMAND_HEADMASK) << 24) 
                        | (((unsigned long) buff.lba.bits16) << 16) 
                        | (((unsigned long) buff.lba.bits08) << 8) 
                        | ((unsigned long) buff.lba.bits00);
                }
                else
                {
                    cyl = buff.chs.cylinder;
                    sect = buff.chs.sector;
                    head = (buff.chs.driveAndHead & ATA_COMMAND_HEADMASK);
                    mylba = img ? (((cyl*img->head + head)*img->sect) + sect-1) : 0;
                }

                workOffset = 0;
                workCount = buff.chs.count;

                if( verboseLevel > 0 )
                {
                    char *comStr = (workCommand & SERIAL_COMMAND_WRITE ? "Write" : "Read");

                    if( workCommand == SERIAL_COMMAND_INQUIRE )
                        log( 1, "Inquire %d: Client Port=0x%x, Client Baud=%s", img == image0 ? 0 : 1,
                             ((unsigned short) buff.inquire.port) << 2,
                             baudRateMatchDivisor( buff.inquire.baud )->display );
                    else if( buff.chs.driveAndHead & ATA_COMMAND_LBA )
                        log( 1, "%s %d: LBA=%u, Count=%u", comStr, img == image0 ? 0 : 1,
                             mylba, workCount );
                    else
                        log( 1, "%s %d: Cylinder=%u, Sector=%u, Head=%u, Count=%u, LBA=%u", comStr, img == image0 ? 0 : 1,
                             cyl, sect, head, workCount, mylba );
                }

                if( !img )
                {
                    log( 1, "    No slave drive provided" );
                    workCount = 0;
                    continue;
                }

                if( (workCommand & SERIAL_COMMAND_WRITE) && img->readOnly )
                {
                    log( 1, "    Write attempt to Read Only disk" );
                    workCount = 0;
                    continue;
                }

                if( verboseLevel > 0 && workCount > 100 )
                    perfTimer = GetTime();
            }

            if( workCount && (workCommand == (SERIAL_COMMAND_WRITE | SERIAL_COMMAND_READWRITE)) )
            {
                //
                // Write command...   Setup to receive a sector
                //
                readto = 514;
            }
            else 
            {
                //
                // Inquire command...
                //
                if( workCommand == SERIAL_COMMAND_INQUIRE )
                {
                    unsigned char localScan;

                    if( serial->speedEmulation && 
                        buff.inquire.baud != serial->baudRate->divisor )
                    {
                        log( 1, "    Ignoring Inquire with wrong baud rate" );
                        workCount = 0;
                        continue;
                    }

                    localScan = buff.inquire.scan;         // need to do this before the call to 
                                                           // img->respondInquire, as it will clear the buff
                    img->respondInquire( &buff.w[0], serial->baudRate, 
                                         ((unsigned short) buff.inquire.port) << 2, 
                                         (img == image1 && lastScan) || buff.inquire.scan );
                    lastScan = localScan;
                }
                //
                // Read command...
                //
                else
                {
                    img->seekSector( mylba + workOffset );
                    img->readSector( &buff.w[0] );
                    lastScan = 0;
                }

                buff.w[256] = checksum( &buff.w[0], 256 );

                if( !serial->writeCharacters( &buff.w[0], 514 ) )
                    break;

                if( verboseLevel >= 3 )
                    logBuff( "    Sending: ", 514, 514, verboseLevel );

                workCount--;
                workOffset++;

                if( workCount )
                    readto = 1;           // looking for continuation ACK
            }
        }

        if( workCount == 0 && workOffset > 100 )
            log( 1, "    Performance: %.2lf bytes per second", (512.0 * workOffset) / (GetTime() - perfTimer) * 1000.0 );
    }
}