From 4178731723a5b2c43bbf6ebeba38e207a7b788c3 Mon Sep 17 00:00:00 2001
From: CSRG <csrg@ucbvax.Berkeley.EDU>
Date: Wed, 2 Dec 1981 20:02:26 -0800
Subject: [PATCH] BSD 4_1_snap development Work on file sys/stand/mt.c

Synthesized-from: CSRG/cd1/4.1.snap
---
 sys/stand/mt.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 sys/stand/mt.c

diff --git a/sys/stand/mt.c b/sys/stand/mt.c
new file mode 100644
index 0000000000..c33451ce14
--- /dev/null
+++ b/sys/stand/mt.c
@@ -0,0 +1,115 @@
+/*	mt.c	4.1	81/12/01	*/
+
+/*
+ * TM78/TU78 tape driver
+ */
+
+#include "../h/mtreg.h"
+#include "../h/param.h"
+#include "../h/inode.h"
+#include "../h/pte.h"
+#include "../h/mbareg.h"
+#include "saio.h"
+#include "savax.h"
+
+short	mttypes[] =
+	{ MBDT_TU78, 0 };
+
+#define	MASKREG(reg)	((reg)&0xffff)
+
+mtopen(io)
+	register struct iob *io;
+{
+	register int skip;
+	register struct mtdevice *mtaddr = (struct mtdevice *)mbadrv(io->i_unit);
+	int i;
+
+	for (i = 0; mttypes[i]; i++)
+		if (mttypes[i] == (mtaddr->mtdt&MBDT_TYPE))
+			goto found;
+	_stop("not a tape\n");
+found:
+	mbainit(UNITTOMBA(io->i_unit));
+	mtaddr->mtid = MTID_CLR;
+	DELAY(250);
+	while ((mtaddr->mtid & MTID_RDY) == 0)
+		;
+	mtstrategy(io, MT_REW);
+	skip = io->i_boff;
+	while (skip--) {
+		io->i_cc = -1;
+		mtstrategy(io, MT_SFORWF);
+	}
+}
+
+mtclose(io)
+	register struct iob *io;
+{
+
+	mtstrategy(io, MT_REW);
+}
+
+mtstrategy(io, func)
+	register struct iob *io;
+	int func;
+{
+	register int errcnt, s, ic;
+	register struct mtdevice *mtaddr =
+	    (struct mtdevice *)mbadrv(io->i_unit);
+
+	errcnt = 0;
+retry:
+	if (func == READ || func == WRITE) {
+		mtaddr->mtca = 1<<2;	/* 1 record */
+		mtaddr->mtbc = io->i_cc;
+		mtaddr->mter = 0;
+		mbastart(io, func);
+		do
+			s = mtaddr->mter & MTER_INTCODE;
+		while (s == 0);
+		ic = s;
+		DELAY(2000);
+	} else {
+		mtaddr->mtas = -1;
+		mtaddr->mtncs[0] = (-io->i_cc << 8)|func|MT_GO;
+	rwait:
+		do
+			s = mtaddr->mtas&0xffff;
+		while (s == 0);
+		mtaddr->mtas = mtaddr->mtas;	/* clear attention */
+		ic = mtaddr->mtner & MTER_INTCODE;
+	}
+	switch (ic) {
+	case MTER_TM:
+	case MTER_EOT:
+	case MTER_LEOT:
+		return (0);
+
+	case MTER_DONE:
+		break;
+
+	case MTER_RWDING:
+		goto rwait;
+	default:
+		printf("mt hard error: er=%b\n",
+		    MASKREG(mtaddr->mter));
+		mtaddr->mtid = MTID_CLR;
+		DELAY(250);
+		while ((mtaddr->mtid & MTID_RDY) == 0)
+			;
+		return (-1);
+
+	case MTER_RETRY:
+		printf("mt error: er=%b\n",
+		    MASKREG(mtaddr->mter));
+		if (errcnt == 10) {
+			printf("mt: unrecovered error\n");
+			return (-1);
+		}
+		errcnt++;
+		goto retry;
+	}
+	if (errcnt)
+		printf("mt: recovered by retry\n");
+	return (io->i_cc);	/* NO PARTIAL RECORD READS!!! */
+}
-- 
2.20.1