1 /* 2 * Copyright (c) 1982 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 6.2 (Berkeley) 06/08/85 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 } 141