usr/sys/dmr/dn.c

#
/*
 *      Copyright 1973 Bell Telephone Laboratories Inc
 */

/*
 * DN-11 ACU interface
 */

#include "../param.h"
#include "../conf.h"
#include "../user.h"

struct dn {
        struct {
                char    dn_stat;
                char    dn_reg;
        } dn11[3];
}

#define DNADDR  0175200

#define PWI     00200
#define ACR     00100
#define DLO     0020
#define DONE    0200
#define IENABLE 0100
#define DSS     040
#define PND     020
#define MENABLE 04
#define DPR     02
#define CRQ     01

#define DNPRI   5

dnopen(dev, flag)
{
        register struct dn *dp;
        register int rdev;

        rdev = dev.d_minor;
        dp = &DNADDR->dn11[rdev];
        if (dp->dn_reg&(PWI|DLO))
                u.u_error = ENXIO;
        else {
                DNADDR->dn11[0].dn_stat =| MENABLE;
                dp->dn_stat = IENABLE|MENABLE|CRQ;
        }
}

dnclose(dev)
{
        DNADDR->dn11[dev.d_minor].dn_stat =& MENABLE;
}

dnwrite(dev)
{
        register struct dn *dp;
        register c;
        extern lbolt;

        dp = &DNADDR->dn11[dev.d_minor];
        for(;;) {
                while ((dp->dn_stat&DONE)==0)
                        sleep(DNADDR, DNPRI);
                dp->dn_stat =& ~DONE;
            contin:
                if (dp->dn_reg&(PWI|ACR)) {
                        u.u_error = EIO;
                        return;
                }
                if (dp->dn_stat&DSS)
                        return;
                c = 0;
                if (u.u_count==0 || (dp->dn_stat&PND)==0 || (c=cpass())<0)
                        continue;
                if (c=='-') {
                        sleep(&lbolt, DNPRI);
                        sleep(&lbolt, DNPRI);
                        goto contin;
                }
                dp->dn_reg = c-'0';
                dp->dn_stat =| DPR;
        }
}

dnint(dev)
{
        wakeup(DNADDR);
}