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Annotation of 43BSD/sys/stand/mt.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1982, 1986 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  *
                      6:  *     @(#)mt.c        7.1 (Berkeley) 6/5/86
                      7:  */
                      8: 
                      9: /*
                     10:  * TM78/TU78 tape driver
                     11:  * Made to work reliably by by Jeffrey R. Schwab (Purdue)
                     12:  */
                     13: #include "../machine/pte.h"
                     14: 
                     15: #include "../h/param.h"
                     16: #include "../h/inode.h"
                     17: #include "../h/fs.h"
                     18: 
                     19: #include "../vaxmba/mtreg.h"
                     20: #include "../vaxmba/mbareg.h"
                     21: 
                     22: #include "saio.h"
                     23: #include "savax.h"
                     24: 
                     25: short  mttypes[] =
                     26:        { MBDT_TU78, 0 };
                     27: 
                     28: #define        MASKREG(reg)    ((reg)&0xffff)
                     29: 
                     30: mtopen(io)
                     31:        register struct iob *io;
                     32: {
                     33:        register int skip;
                     34:        register struct mtdevice *mtaddr =
                     35:                (struct mtdevice *)mbadrv(io->i_unit);
                     36:        int i;
                     37: 
                     38:        for (i = 0; mttypes[i]; i++)
                     39:                if (mttypes[i] == (mtaddr->mtdt&MBDT_TYPE))
                     40:                        goto found;
                     41:        _stop("not a tape\n");
                     42: found:
                     43:        mbainit(UNITTOMBA(io->i_unit));
                     44:        mtaddr->mtid = MTID_CLR;
                     45:        DELAY(250);
                     46:        while ((mtaddr->mtid & MTID_RDY) == 0)
                     47:                ;
                     48: 
                     49:        /* clear any attention bits present on open */
                     50:        i = mtaddr->mtner;
                     51:        mtaddr->mtas = mtaddr->mtas;
                     52: 
                     53:        mtstrategy(io, MT_REW);
                     54:        skip = io->i_boff;
                     55:        while (skip--) {
                     56:                io->i_cc = -1;
                     57:                mtstrategy(io, MT_SFORWF);
                     58:        }
                     59: }
                     60: 
                     61: mtclose(io)
                     62:        register struct iob *io;
                     63: {
                     64: 
                     65:        mtstrategy(io, MT_REW);
                     66: }
                     67: 
                     68: mtstrategy(io, func)
                     69:        register struct iob *io;
                     70:        int func;
                     71: {
                     72:        register int errcnt, s, ic;
                     73:        register struct mtdevice *mtaddr =
                     74:            (struct mtdevice *)mbadrv(io->i_unit);
                     75:        struct mba_regs *mba = mbamba(io->i_unit);
                     76: 
                     77:        errcnt = 0;
                     78: retry:
                     79:        /* code to trap for attention up prior to start of command */
                     80:        if ((mtaddr->mtas & 0xffff) != 0) {
                     81:                printf("mt unexpected attention er=%x - continuing\n",
                     82:                        MASKREG(mtaddr->mtner));
                     83:                mtaddr->mtas = mtaddr->mtas;
                     84:        }
                     85: 
                     86:        if (func == READ || func == WRITE) {
                     87:                mtaddr->mtca = 1<<2;    /* 1 record */
                     88:                mtaddr->mtbc = io->i_cc;
                     89:                mbastart(io, func);
                     90:                /* wait for mba to go idle and read result status */
                     91:                while((mba->mba_sr & MBSR_DTBUSY) != 0)
                     92:                        ;
                     93:                ic = mtaddr->mter & MTER_INTCODE;
                     94:        } else {
                     95:                mtaddr->mtncs[0] = (-io->i_cc << 8)|func|MT_GO;
                     96:        rwait:
                     97:                do
                     98:                        s = mtaddr->mtas&0xffff;
                     99:                while (s == 0);
                    100:                ic = mtaddr->mtner & MTER_INTCODE;
                    101:                mtaddr->mtas = mtaddr->mtas;    /* clear attention */
                    102:        }
                    103:        switch (ic) {
                    104:        case MTER_TM:
                    105:        case MTER_EOT:
                    106:        case MTER_LEOT:
                    107:                return (0);
                    108: 
                    109:        case MTER_DONE:
                    110:                /* make sure a record was read */
                    111:                if ((mtaddr->mtca & (1 << 2)) != 0) {
                    112:                        printf("mt record count not decremented - retrying\n");
                    113:                        goto retry;
                    114:                }
                    115:                break;
                    116: 
                    117:        case MTER_RWDING:
                    118:                goto rwait;
                    119:        default:
                    120:                printf("mt hard error: er=%x\n",
                    121:                    MASKREG(mtaddr->mter));
                    122:                mtaddr->mtid = MTID_CLR;
                    123:                DELAY(250);
                    124:                while ((mtaddr->mtid & MTID_RDY) == 0)
                    125:                        ;
                    126:                return (-1);
                    127: 
                    128:        case MTER_RETRY:
                    129:                printf("mt error: er=%x\n", MASKREG(mtaddr->mter));
                    130:                if (errcnt == 10) {
                    131:                        printf("mt: unrecovered error\n");
                    132:                        return (-1);
                    133:                }
                    134:                errcnt++;
                    135:                goto retry;
                    136:        }
                    137:        if (errcnt)
                    138:                printf("mt: recovered by retry\n");
                    139:        return (io->i_cc);      /* NO PARTIAL RECORD READS!!! */
                    140: }

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