From 0d469f507f78ea64ef3e035ad23cbbd440fc868c Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sun, 13 Aug 2000 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2000-08-13

---
 pc/devfloppy.c | 51 ++++++++++++++++++++++++++++++++++++--------------
 pc/devlpt.c    | 14 ++++++++------
 pc/floppy.h    |  3 ++-
 3 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/pc/devfloppy.c b/pc/devfloppy.c
index f5290791e6be9c0da604d1cf7c831b46e668aace..132deaa5f53eebbd5d9bc64f543a47c2b4cb955e 100644
--- a/pc/devfloppy.c
+++ b/pc/devfloppy.c
@@ -100,7 +100,7 @@ static int	floppyresult(void);
 static void	floppyrevive(void);
 static long	floppyseek(FDrive*, long);
 static int	floppysense(void);
-static void	floppywait(void);
+static void	floppywait(int);
 static long	floppyxfer(FDrive*, int, void*, long, long);
 
 Dirtab floppydir[]={
@@ -272,12 +272,24 @@ changed(Chan *c, FDrive *dp)
 		DPRINT("changed\n");
 		fldump();
 		dp->vers++;
-		floppysetdef(dp);
 		start = dp->t;
+		dp->maxtries = 3;	/* limit it when we're probing */
+
+		/* floppyon will fail if there's a controller but no drive */
 		dp->confused = 1;	/* make floppyon recal */
-		floppyon(dp);
+		if(floppyon(dp) < 0)
+			error(Eio);
+
+		/* seek to the first track */
 		floppyseek(dp, dp->t->heads*dp->t->tsize);
 		while(waserror()){
+			/*
+			 *  if first attempt doesn't reset changed bit, there's
+			 *  no floppy there
+			 */
+			if(inb(Pdir)&Fchange)
+				nexterror();
+
 			while(++dp->t){
 				if(dp->t == &floppytype[nelem(floppytype)])
 					dp->t = floppytype;
@@ -285,14 +297,21 @@ changed(Chan *c, FDrive *dp)
 					break;
 			}
 			floppydir[NFDIR*dp->dev].length = dp->t->cap;
-			floppyon(dp);
+
+			/* floppyon will fail if there's a controller but no drive */
+			if(floppyon(dp) < 0)
+				error(Eio);
+
 			DPRINT("changed: trying %s\n", dp->t->name);
 			fldump();
 			if(dp->t == start)
 				nexterror();
 		}
+
+		/* if the read succeeds, we've got the density right */
 		floppyxfer(dp, Fread, dp->cache, 0, dp->t->tsize);
 		poperror();
+		dp->maxtries = 20;
 	}
 
 	old = c->qid.vers;
@@ -467,7 +486,7 @@ floppykproc(void *)
 /*
  *  start a floppy drive's motor.
  */
-static void
+static int
 floppyon(FDrive *dp)
 {
 	int alreadyon;
@@ -501,6 +520,11 @@ floppyon(FDrive *dp)
 				break;
 	dp->lasttouched = m->ticks;
 	fl.selected = dp;
+
+	/* return -1 if this didn't work */
+	if(dp->confused)
+		return -1;
+	return 0;
 }
 
 /*
@@ -639,9 +663,9 @@ cmddone(void *)
  *  routine to try to clear any conditions.
  */
 static void
-floppywait(void)
+floppywait(int slow)
 {
-	tsleep(&fl.r, cmddone, 0, 5000);
+	tsleep(&fl.r, cmddone, 0, slow ? 5000 : 1000);
 	if(!cmddone(0)){
 		floppyintr(0);
 		fl.confused = 1;
@@ -662,7 +686,7 @@ floppyrecal(FDrive *dp)
 	fl.cmd[fl.ncmd++] = dp->dev;
 	if(floppycmd() < 0)
 		return -1;
-	floppywait();
+	floppywait(1);
 	if(fl.nstat < 2){
 		DPRINT("recalibrate: confused %ux\n", inb(Pmsr));
 		fl.confused = 1;
@@ -712,7 +736,7 @@ floppyrevive(void)
 		spllo();
 		fl.motor = 0;
 		fl.confused = 0;
-		floppywait();
+		floppywait(0);
 
 		/* mark all drives in an unknown state */
 		for(dp = fl.d; dp < &fl.d[fl.ndrive]; dp++)
@@ -746,7 +770,7 @@ floppyseek(FDrive *dp, long off)
 	fl.cmd[fl.ncmd++] = dp->tcyl * dp->t->steps;
 	if(floppycmd() < 0)
 		return -1;
-	floppywait();
+	floppywait(1);
 	if(fl.nstat < 2){
 		DPRINT("seek: confused\n");
 		fl.confused = 1;
@@ -779,10 +803,9 @@ floppyxfer(FDrive *dp, int cmd, void *a, long off, long n)
 	/* retry on error (until it gets ridiculous) */
 	tries = 0;
 	while(waserror()){
-		if(tries++ > 20)
+		if(tries++ >= dp->maxtries)
 			nexterror();
 		DPRINT("floppyxfer: retrying\n");
-		/*floppyon(dp);*/
 	}
 
 	dp->len = n;
@@ -825,7 +848,7 @@ floppyxfer(FDrive *dp, int cmd, void *a, long off, long n)
 	/*
 	 *  give bus to DMA, floppyintr() will read result
 	 */
-	floppywait();
+	floppywait(0);
 	dmaend(DMAchan);
 	poperror();
 
@@ -961,7 +984,7 @@ floppyformat(FDrive *dp, char *params)
 		/*
 		 *  give bus to DMA, floppyintr() will read result
 		 */
-		floppywait();
+		floppywait(1);
 		dmaend(DMAchan);
 		poperror();
 
diff --git a/pc/devlpt.c b/pc/devlpt.c
index 23a0e3e854a24699d56fb21776ef8aecc6e2ac85..72ab3a6e62a6b4416f8a6dc528c2b4a9331b4914 100644
--- a/pc/devlpt.c
+++ b/pc/devlpt.c
@@ -178,15 +178,17 @@ outch(int base, int c)
 {
 	int status, tries;
 
-	for(tries = 0;; tries++){
+	for(tries=0;; tries++) {
 		status = inb(base+Qpsr);
-		if(!(status & Fselect) || !(status & Fnoerror))
-			error(Eio);
-		if(status & Fnotbusy)
+		if(status&Fnotbusy)
 			break;
-		if(tries > 1000){
+		if((status&Fpe)==0 && (status&(Fselect|Fnoerror)) != (Fselect|Fnoerror))
+			error(Eio);
+		if(tries < 10)
+			tsleep(&lptrendez, return0, nil, 1);
+		else {
 			outb(base+Qpcr, Finitbar|Fie);
-			tsleep(&lptrendez, lptready, (void *)base, MS2HZ);
+			tsleep(&lptrendez, lptready, (void *)base, 100);
 		}
 	}
 	outb(base+Qdlr, c);
diff --git a/pc/floppy.h b/pc/floppy.h
index a897b5223b986e732a530857c28818a542518a2f..86c4c4dd12ffb76db5858d6424e3a531a51fd3d1 100644
--- a/pc/floppy.h
+++ b/pc/floppy.h
@@ -3,7 +3,7 @@ typedef	struct FDrive FDrive;
 typedef struct FType FType;
 
 static void floppyintr(Ureg*);
-static void floppyon(FDrive*);
+static int floppyon(FDrive*);
 static void floppyoff(FDrive*);
 static void floppysetdef(FDrive*);
 
@@ -20,6 +20,7 @@ struct FDrive
 	int	cyl;		/* current arm position */
 	int	confused;	/* needs to be recalibrated */
 	int	vers;
+	int	maxtries;	/* max read attempts before Eio */
 
 	int	tcyl;		/* target cylinder */
 	int	thead;		/* target head */