minnie.tuhs.org/unixen.tar/unixen/PDP-11/Trees/V7/usr/sys/dev/orig_rl.c

C/C++ Source or Header | 1998-02-03 | 3.8 KB | 216 lines

/*
 *  RL disk driver
 */

#define DK_N    2
#include "../h/param.h"
#include "../h/buf.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/systm.h"

#define NRLBLK 10240
#define RLCYLSZ 10240
#define RLSECSZ 256

#define RESET 013
#define STAT 03
#define GETSTAT 04
#define WCOM 012
#define RCOM 014
#define SEEK 06
#define SEEKHI 5
#define SEEKLO 1
#define RDHDR 010
#define IENABLE 0100
#define CRDY 0200
#define OPI 02000
#define CRCERR 04000
#define TIMOUT 010000
#define NXM 020000
#define DE  040000

struct device
{
    int rlcs, rlba, rlda, rlmp;
};

#define RLADDR    ((struct device *)0174400)
#define RL_CNT 1
struct    buf    rrlbuf;
struct    buf    rltab;

struct
{
    int    cn[4];        /* location of heads for each drive */
    int    dn;        /* drive number */
    int    com;        /* read or write command word */
    int    chn;        /* cylinder and head number */
    unsigned int    bleft;    /* bytes left to be transferred */
    unsigned int    bpart;    /* number of bytes transferred */
    int    sn;        /* sector number */
    union {
        int    w[2];
        long    l;
    } addr;            /* address of memory for transfer */

}    rl = {-1,-1,-1,-1};

rlstrategy(bp)
register struct buf *bp;
{
    if(bp->b_blkno >= NRLBLK) {
        if(bp->b_blkno == NRLBLK && bp->b_flags&B_READ)
            bp->b_resid = bp->b_bcount;
        else {
            bp->b_flags |= B_ERROR;
            bp->b_error = ENXIO;
        }
        iodone(bp);
        return;
    }
    bp->av_forw = NULL;
    spl5();
    if(rltab.b_actf == NULL)
        rltab.b_actf = bp;
    else
        rltab.b_actl->av_forw = bp;
    rltab.b_actl = bp;
    if(rltab.b_active == NULL)
        rlstart();
    spl0();
}

rlstart()
{

    register struct buf *bp;

    if ((bp = rltab.b_actf) == NULL)
        return;
    rltab.b_active++;
    rl.dn = minor(bp->b_dev);
    rl.chn = bp->b_blkno/20;
    rl.sn = (bp->b_blkno%20) << 1;
    rl.bleft = bp->b_bcount;
    rl.addr.w[0] = bp->b_xmem & 3;
    rl.addr.w[1] = (int)bp->b_un.b_addr;
    rl.com = (rl.dn << 8) | IENABLE;
    if (bp->b_flags & B_READ)
        rl.com |= RCOM;
    else
        rl.com |= WCOM;
    rlio();
}

rlintr()
{
    register struct buf *bp;
    register struct device *rp;
    register int status;

    rp = RLADDR;
    if (rltab.b_active == NULL) {
/*
        logstray(rp);
*/
        return;
    }
    bp = rltab.b_actf;
    dk_busy &= ~(1<<DK_N);
    if (rp->rlcs < 0) {        /* error bit */
        if (rp->rlcs & 036000) {
            if(rltab.b_errcnt > 2)
                deverror(bp, rp->rlcs, rp->rlda);
        }
        if (rp->rlcs & 040000) {
            rp->rlda = STAT;
            rp->rlcs = (rl.dn << 8) | GETSTAT;
            while ((rp->rlcs & CRDY) == 0)
                ;
            status = rp->rlmp;
            if(rltab.b_errcnt > 2)
                deverror(bp, status, rp->rlda);
            rp->rlda = RESET;
            rp->rlcs = (rl.dn << 8) | GETSTAT;
            while ((rp->rlcs & CRDY) == 0)
                ;
            if(status & 01000) {
                rlstart();
                return;
            }
        }
        if (++rltab.b_errcnt <= 10) {
            rl.cn[rl.dn] = -1;
            rlstart();
            return;
        }
        else {
            bp->b_flags |= B_ERROR;
            rl.bpart = rl.bleft;
        }
    }

    if ((rl.bleft -= rl.bpart) > 0) {
        rl.addr.l += rl.bpart;
        rl.sn=0;
        rl.chn++;
        rlio();
        return;
    }
    rltab.b_active = NULL;
    rltab.b_errcnt = 0;
    rltab.b_actf = bp->av_forw;
    bp->b_resid = 0;
    iodone(bp);
    rlstart();
}

rlio()
{

    register struct device *rp;
    register dif;
    register int head;

    rp = RLADDR;
    dk_busy |= 1<<DK_N;
    dk_numb[DK_N] += 1;
    head = rl.bpart>>6;
    dk_wds[DK_N] += head;
    if (rl.cn[rl.dn] < 0) {
        rp->rlcs = (rl.dn << 8) | RDHDR;
        while ((rp->rlcs&CRDY) == 0)
            ;
        rl.cn[rl.dn] = (rp->rlmp&077700) >> 6;
    }
    dif =(rl.cn[rl.dn] >> 1) - (rl.chn >>1);
    head = (rl.chn & 1) << 4;
    if (dif < 0)
        rp->rlda = (-dif <<7) | SEEKHI | head;
    else
        rp->rlda = (dif << 7) | SEEKLO | head;
    rp->rlcs = (rl.dn << 8) | SEEK;
    rl.cn[rl.dn] = rl.chn;
    if (rl.bleft < (rl.bpart = RLCYLSZ - (rl.sn * RLSECSZ)))
        rl.bpart = rl.bleft;
    while ((rp->rlcs&CRDY) == 0)
        ;
    rp->rlda = (rl.chn << 6) | rl.sn;
    rp->rlba = rl.addr.w[1];
    rp->rlmp = -(rl.bpart >> 1);
    rp->rlcs = rl.com | rl.addr.w[0] << 4;
}

rlread(dev)
{

    physio(rlstrategy, &rrlbuf, dev, B_READ);
}

rlwrite(dev)
{

    physio(rlstrategy, &rrlbuf, dev, B_WRITE);
}