From b49e078ffc66ebccab7e10d5a2de38571ca9f4ab Mon Sep 17 00:00:00 2001
From: Dennis Ritchie <dmr@research.uucp>
Date: Tue, 26 Nov 1974 18:13:21 -0500
Subject: [PATCH] Research V5 development Work on file usr/sys/dmr/tm.c

Synthesized-from: v5
---
 usr/sys/dmr/tm.c | 222 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 222 insertions(+)
 create mode 100644 usr/sys/dmr/tm.c

diff --git a/usr/sys/dmr/tm.c b/usr/sys/dmr/tm.c
new file mode 100644
index 0000000000..57b12c79e0
--- /dev/null
+++ b/usr/sys/dmr/tm.c
@@ -0,0 +1,222 @@
+#
+/*
+ *	Copyright 1973 Bell Telephone Laboratories Inc
+ */
+
+/*
+ * TM tape driver
+ */
+
+#include "../param.h"
+#include "../buf.h"
+#include "../conf.h"
+#include "../user.h"
+
+struct {
+	int tmer;
+	int tmcs;
+	int tmbc;
+	int tmba;
+	int tmdb;
+	int tmrd;
+};
+
+struct	devtab	tmtab;
+struct	buf	rtmbuf;
+
+char	t_openf[8];
+char	*t_blkno[8];
+char	*t_nxrec[8];
+
+#define	TMADDR	0172520
+
+#define	GO	01
+#define	RCOM	02
+#define	WCOM	04
+#define	WEOF	06
+#define	SFORW	010
+#define	SREV	012
+#define	WIRG	014
+#define	REW	016
+#define	DENS	060000		/* 9-channel */
+#define	IENABLE	0100
+#define	CRDY	0200
+#define GAPSD	010000
+#define	TUR	1
+#define	HARD	0102200	/* ILC, EOT, NXM */
+#define	EOF	0040000
+
+#define	SSEEK	1
+#define	SIO	2
+
+tmopen(dev, flag)
+{
+	register dminor;
+
+	dminor = dev.d_minor;
+	if (t_openf[dminor])
+		u.u_error = ENXIO;
+	else {
+		t_openf[dminor]++;
+		t_blkno[dminor] = 0;
+		t_nxrec[dminor] = 65535;
+	}
+}
+
+tmclose(dev, flag)
+{
+	register int dminor;
+
+	dminor = dev.d_minor;
+	t_openf[dminor] = 0;
+	if (flag)
+		tcommand(dminor, WEOF);
+	tcommand(dminor, REW);
+}
+
+tcommand(unit, com)
+{
+	extern lbolt;
+
+	while (tmtab.d_active || (TMADDR->tmcs & CRDY)==0)
+		sleep(&lbolt, 1);
+	TMADDR->tmcs = DENS|com|GO | (unit<<8);
+}
+
+tmstrategy(abp)
+struct buf *abp;
+{
+	register struct buf *bp;
+	register char **p;
+
+	bp = abp;
+	p = &t_nxrec[bp->b_dev.d_minor];
+	if (*p <= bp->b_blkno) {
+		if (*p < bp->b_blkno) {
+			bp->b_flags =| B_ERROR;
+			iodone(bp);
+			return;
+		}
+		if (bp->b_flags&B_READ) {
+			clrbuf(bp);
+			iodone(bp);
+			return;
+		}
+	}
+	if ((bp->b_flags&B_READ)==0)
+		*p = bp->b_blkno + 1;
+	bp->av_forw = 0;
+	spl5();
+	if (tmtab.d_actf==0)
+		tmtab.d_actf = bp;
+	else
+		tmtab.d_actl->av_forw = bp;
+	tmtab.d_actl = bp;
+	if (tmtab.d_active==0)
+		tmstart();
+	spl0();
+}
+
+tmstart()
+{
+	register struct buf *bp;
+	register int com;
+	int unit;
+	register char *blkno;
+
+    loop:
+	if ((bp = tmtab.d_actf) == 0)
+		return;
+	unit = bp->b_dev.d_minor;
+	blkno = t_blkno[unit];
+	if (t_openf[unit] < 0 || (TMADDR->tmcs & CRDY)==0) {
+		bp->b_flags =| B_ERROR;
+		tmtab.d_actf = bp->av_forw;
+		iodone(bp);
+		goto loop;
+	}
+	com = (unit<<8) | (bp->b_flags&B_XMEM) | IENABLE|DENS;
+	if (blkno != bp->b_blkno) {
+		tmtab.d_active = SSEEK;
+		if (blkno < bp->b_blkno) {
+			com =| SFORW|GO;
+			TMADDR->tmbc = blkno - bp->b_blkno;
+		} else {
+			if (bp->b_blkno == 0)
+				com =| REW|GO;
+			else {
+				com =| SREV|GO;
+				TMADDR->tmbc = bp->b_blkno - blkno;
+			}
+		}
+		TMADDR->tmcs = com;
+		return;
+	}
+	tmtab.d_active = SIO;
+	TMADDR->tmbc = bp->b_wcount << 1;
+	TMADDR->tmba = bp->b_addr;		/* core address */
+	TMADDR->tmcs = com | ((bp->b_flags&B_READ)? RCOM|GO:
+	    ((tmtab.d_errcnt)? WIRG|GO: WCOM|GO));
+}
+
+tmintr()
+{
+	register struct buf *bp;
+	register int unit;
+
+	if ((bp = tmtab.d_actf)==0)
+		return;
+	unit = bp->b_dev.d_minor;
+	if (TMADDR->tmcs < 0) {		/* error bit */
+/*
+		deverror(bp, TMADDR->tmer);
+ */
+		while(TMADDR->tmrd & GAPSD) ; /* wait for gap shutdown */
+		if ((TMADDR->tmer&(HARD|EOF))==0 && tmtab.d_active==SIO) {
+			if (++tmtab.d_errcnt < 10) {
+				t_blkno[unit]++;
+				tmtab.d_active = 0;
+				tmstart();
+				return;
+			}
+		} else
+			if(bp != &rtmbuf && (TMADDR->tmer&EOF)==0)
+				t_openf[unit] = -1;
+		bp->b_flags =| B_ERROR;
+		tmtab.d_active = SIO;
+	}
+	if (tmtab.d_active == SIO) {
+		tmtab.d_errcnt = 0;
+		t_blkno[unit]++;
+		tmtab.d_actf = bp->av_forw;
+		tmtab.d_active = 0;
+		iodone(bp);
+		bp->b_resid = TMADDR->tmbc;
+	} else
+		t_blkno[unit] = bp->b_blkno;
+	tmstart();
+}
+
+tmread(dev)
+{
+	tmphys(dev);
+	physio(tmstrategy, &rtmbuf, dev, B_READ);
+	u.u_count = -rtmbuf.b_resid;
+}
+
+tmwrite(dev)
+{
+	tmphys(dev);
+	physio(tmstrategy, &rtmbuf, dev, B_WRITE);
+	u.u_count = 0;
+}
+
+tmphys(dev)
+{
+	register unit, a;
+
+	unit = dev.d_minor;
+	a = lshift(u.u_offset, -9);
+	t_blkno[unit] = a;
+	t_nxrec[unit] = ++a;
+}
-- 
2.20.1