Another large patchset from Bruce.

Despite of a few cosmetic things like adding ``irritating silly
parentheses'' around all return values, this mainly improves FDC reset
handling by no longer gratuitously resetting the FDC all the time
(which causes it to lose the notion of the current track) but only in
case of errors, and it sanitizes the block and offset calculations in
fdstrategy() and fdstate().  Some additional cleanup added by me, in
particular the large switch in fdstate() now always uses return to
break out, and no branch falls off the end of the switch statement
anymore.  Per Bruce's suggestion, removed M_NOWAIT from the malloc()s
to simplify things.

Submitted by:	bde (mostly)

1 files changed, 113 insertions, 158 deletions

diff --git a/sys/isa/fd.c b/sys/isa/fd.c
index da45cb2..236edba 100644
--- a/sys/isa/fd.c
+++ b/sys/isa/fd.c
@@ -852,7 +852,7 @@ fdc_attach(device_t dev)
 		return error;
 	}
 	fdc->fdcu = device_get_unit(dev);
-	fdc->flags |= FDC_ATTACHED;
+	fdc->flags |= FDC_ATTACHED | FDC_NEEDS_RESET;
 
 	if ((fdc->flags & FDC_NODMA) == 0) {
 		/*
@@ -1067,6 +1067,7 @@ fd_probe(device_t dev)
 
 	/* select it */
 	set_motor(fdc, fdsu, TURNON);
+	fdc_reset(fdc);		/* XXX reset, then unreset, etc. */
 	DELAY(1000000);	/* 1 sec */
 
 	/* XXX This doesn't work before the first set_motor() */
@@ -1231,45 +1232,17 @@ DRIVER_MODULE(fd, fdc, fd_driver, fd_devclass, 0, 0);
 static void
 set_motor(struct fdc_data *fdc, int fdsu, int turnon)
 {
-	int fdout = fdc->fdout;
-	int needspecify = 0;
+	int fdout;
 
-	if(turnon) {
+	fdout = fdc->fdout;
+	if (turnon) {
 		fdout &= ~FDO_FDSEL;
-		fdout |= (FDO_MOEN0 << fdsu) + fdsu;
+		fdout |= (FDO_MOEN0 << fdsu) | FDO_FDMAEN | FDO_FRST | fdsu;
 	} else
 		fdout &= ~(FDO_MOEN0 << fdsu);
-
-	if(!turnon
-	   && (fdout & (FDO_MOEN0+FDO_MOEN1+FDO_MOEN2+FDO_MOEN3)) == 0)
-		/* gonna turn off the last drive, put FDC to bed */
-		fdout &= ~ (FDO_FRST|FDO_FDMAEN);
-	else {
-		/* make sure controller is selected and specified */
-		if((fdout & (FDO_FRST|FDO_FDMAEN)) == 0)
-			needspecify = 1;
-		fdout |= (FDO_FRST|FDO_FDMAEN);
-	}
-
-	fdout_wr(fdc, fdout);
 	fdc->fdout = fdout;
+	fdout_wr(fdc, fdout);
 	TRACE1("[0x%x->FDOUT]", fdout);
-
-	if (needspecify) {
-		/*
-		 * we silently assume the command will be accepted
-		 * after an FDC reset
-		 *
-		 * Steinbach's Guideline for Systems Programming:
-		 * Never test for an error condition you don't know
-		 * how to handle.
-		 */
-		(void)fd_cmd(fdc, 3, NE7CMD_SPECIFY,
-			     NE7_SPEC_1(3, 240), NE7_SPEC_2(2, 0),
-			     0);
-		if (fdc->flags & FDC_HAS_FIFO)
-			(void) enable_fifo(fdc);
-	}
 }
 
 static void
@@ -1501,7 +1474,7 @@ fdclose(dev_t dev, int flags, int mode, struct proc *p)
 void
 fdstrategy(struct bio *bp)
 {
-	unsigned nblocks, blknum, cando;
+	long blknum, nblocks;
  	int	s;
  	fdu_t	fdu;
  	fdc_p	fdc;
@@ -1548,20 +1521,19 @@ fdstrategy(struct bio *bp)
 		bp->bio_flags |= BIO_ERROR;
 		goto bad;
 	}
-	blknum = (unsigned) bp->bio_blkno * DEV_BSIZE/fdblk;
+	blknum = bp->bio_blkno * DEV_BSIZE / fdblk;
  	nblocks = fd->ft->size;
-	bp->bio_resid = 0;
-	if (blknum + (bp->bio_bcount / fdblk) > nblocks) {
-		if (blknum <= nblocks) {
-			cando = (nblocks - blknum) * fdblk;
-			bp->bio_resid = bp->bio_bcount - cando;
-			if (cando == 0)
-				goto bad;	/* not actually bad but EOF */
-		} else {
-			bp->bio_error = EINVAL;
-			bp->bio_flags |= BIO_ERROR;
-			goto bad;
+	if (blknum + bp->bio_bcount / fdblk > nblocks) {
+		if (blknum >= nblocks) {
+			if (bp->bio_cmd == BIO_READ)
+				bp->bio_resid = bp->bio_bcount;
+			else {
+				bp->bio_error = ENOSPC;
+				bp->bio_flags |= BIO_ERROR;
+			}
+			goto bad;	/* not always bad, but EOF */
 		}
+		bp->bio_bcount = (nblocks - blknum) * fdblk;
 	}
  	bp->bio_pblkno = bp->bio_blkno;
 	s = splbio();
@@ -1692,9 +1664,10 @@ fdcpio(fdc_p fdc, long flags, caddr_t addr, u_int count)
 static int
 fdstate(fdc_p fdc)
 {
-	int read, format, rdsectid, head, i, sec = 0, sectrac, st0, cyl, st3, idf;
-	unsigned blknum = 0, b_cylinder = 0;
 	struct fdc_readid *idp;
+	int read, format, rdsectid, cylinder, head, i, sec = 0, sectrac;
+	int st0, cyl, st3, idf;
+	unsigned long blknum;
 	fdu_t fdu = fdc->fdu;
 	fd_p fd;
 	register struct bio *bp;
@@ -1736,16 +1709,8 @@ fdstate(fdc_p fdc)
 		idf = ISADMA_WRITE;
 	format = bp->bio_cmd == BIO_FORMAT;
 	rdsectid = bp->bio_cmd == BIO_RDSECTID;
-	if (format) {
+	if (format)
 		finfo = (struct fd_formb *)bp->bio_data;
-		fd->skip = (char *)&(finfo->fd_formb_cylno(0))
-			- (char *)finfo;
-	}
-	if (fdc->state == DOSEEK || fdc->state == SEEKCOMPLETE) {
-		blknum = (unsigned) bp->bio_pblkno * DEV_BSIZE/fdblk +
-			fd->skip/fdblk;
-		b_cylinder = blknum / (fd->ft->sectrac * fd->ft->heads);
-	}
 	TRACE1("fd%d", fdu);
 	TRACE1("[%s]", fdstates[fdc->state]);
 	TRACE1("(0x%x)", fd->flags);
@@ -1787,15 +1752,18 @@ fdstate(fdc_p fdc)
 			fdc->flags &= ~FDC_NEEDS_RESET;
 		} else
 			fdc->state = DOSEEK;
-		break;
+		return (1);	/* come back immediately */
+
 	case DOSEEK:
-		if (b_cylinder == (unsigned)fd->track)
+		blknum = bp->bio_pblkno + fd->skip / fdblk;
+		cylinder = blknum / (fd->ft->sectrac * fd->ft->heads);
+		if (cylinder == fd->track)
 		{
 			fdc->state = SEEKCOMPLETE;
-			break;
+			return (1); /* come back immediately */
 		}
 		if (fd_cmd(fdc, 3, NE7CMD_SEEK,
-			   fd->fdsu, b_cylinder * fd->ft->steptrac,
+			   fd->fdsu, cylinder * fd->ft->steptrac,
 			   0))
 		{
 			/*
@@ -1808,15 +1776,20 @@ fdstate(fdc_p fdc)
 		fd->track = FD_NO_TRACK;
 		fdc->state = SEEKWAIT;
 		return(0);	/* will return later */
+
 	case SEEKWAIT:
 		/* allow heads to settle */
 		timeout(fd_pseudointr, fdc, hz / 16);
 		fdc->state = SEEKCOMPLETE;
 		return(0);	/* will return later */
+
 	case SEEKCOMPLETE : /* SEEK DONE, START DMA */
+		blknum = bp->bio_pblkno + fd->skip / fdblk;
+		cylinder = blknum / (fd->ft->sectrac * fd->ft->heads);
+
 		/* Make sure seek really happened*/
 		if(fd->track == FD_NO_TRACK) {
-			int descyl = b_cylinder * fd->ft->steptrac;
+			int descyl = cylinder * fd->ft->steptrac;
 			do {
 				/*
 				 * This might be a "ready changed" interrupt,
@@ -1879,10 +1852,14 @@ fdstate(fdc_p fdc)
 			}
 		}
 
-		fd->track = b_cylinder;
+		fd->track = cylinder;
+		if (format)
+			fd->skip = (char *)&(finfo->fd_formb_cylno(0))
+			    - (char *)finfo;
 		if (!rdsectid && !(fdc->flags & FDC_NODMA))
 			isa_dmastart(idf, bp->bio_data+fd->skip,
 				format ? bp->bio_bcount : fdblk, fdc->dmachan);
+		blknum = bp->bio_pblkno + fd->skip / fdblk;
 		sectrac = fd->ft->sectrac;
 		sec = blknum %  (sectrac * fd->ft->heads);
 		head = sec / sectrac;
@@ -2023,6 +2000,7 @@ fdstate(fdc_p fdc)
 		fdc->state = IOCOMPLETE;
 		fd->tohandle = timeout(fd_iotimeout, fdc, hz);
 		return (0);	/* will return later */
+
 	case PIOREAD:
 		/* 
 		 * actually perform the PIO read.  The IOCOMPLETE case
@@ -2047,7 +2025,6 @@ fdstate(fdc_p fdc)
 		fdc->state = IOTIMEDOUT;
 
 		/* FALLTHROUGH */
-
 	case IOTIMEDOUT:
 		if (!rdsectid && !(fdc->flags & FDC_NODMA))
 			isa_dmadone(idf, bp->bio_data + fd->skip,
@@ -2084,12 +2061,13 @@ fdstate(fdc_p fdc)
 			idp->secshift = fdc->status[6];
 		}
 		fd->skip += fdblk;
-		if (!rdsectid && !format && fd->skip < bp->bio_bcount - bp->bio_resid) {
+		if (!rdsectid && !format && fd->skip < bp->bio_bcount) {
 			/* set up next transfer */
 			fdc->state = DOSEEK;
 		} else {
 			/* ALL DONE */
 			fd->skip = 0;
+			bp->bio_resid = 0;
 			fdc->bp = NULL;
 			device_unbusy(fd->dev);
 			biofinish(bp, &fd->device_stats, 0);
@@ -2098,11 +2076,13 @@ fdstate(fdc_p fdc)
 			fdc->state = FINDWORK;
 		}
 		return (1);
+
 	case RESETCTLR:
 		fdc_reset(fdc);
 		fdc->retry++;
 		fdc->state = RESETCOMPLETE;
 		return (0);
+
 	case RESETCOMPLETE:
 		/*
 		 * Discard all the results from the reset so that they
@@ -2111,7 +2091,7 @@ fdstate(fdc_p fdc)
 		for (i = 0; i < 4; i++)
 			(void)fd_sense_int(fdc, &st0, &cyl);
 		fdc->state = STARTRECAL;
-		/* Fall through. */
+		/* FALLTHROUGH */
 	case STARTRECAL:
 		if(fd_cmd(fdc, 2, NE7CMD_RECAL, fdu, 0)) {
 			/* arrgl */
@@ -2120,11 +2100,13 @@ fdstate(fdc_p fdc)
 		}
 		fdc->state = RECALWAIT;
 		return (0);	/* will return later */
+
 	case RECALWAIT:
 		/* allow heads to settle */
 		timeout(fd_pseudointr, fdc, hz / 8);
 		fdc->state = RECALCOMPLETE;
 		return (0);	/* will return later */
+
 	case RECALCOMPLETE:
 		do {
 			/*
@@ -2156,6 +2138,7 @@ fdstate(fdc_p fdc)
 		/* Seek (probably) necessary */
 		fdc->state = DOSEEK;
 		return (1);	/* will return immediatly */
+
 	case MOTORWAIT:
 		if(fd->flags & FD_MOTOR_WAIT)
 		{
@@ -2164,16 +2147,10 @@ fdstate(fdc_p fdc)
 		if (fdc->flags & FDC_NEEDS_RESET) {
 			fdc->state = RESETCTLR;
 			fdc->flags &= ~FDC_NEEDS_RESET;
-		} else {
-			/*
-			 * If all motors were off, then the controller was
-			 * reset, so it has lost track of the current
-			 * cylinder.  Recalibrate to handle this case.
-			 * But first, discard the results of the reset.
-			 */
-			fdc->state = RESETCOMPLETE;
-		}
+		} else
+			fdc->state = DOSEEK;
 		return (1);	/* will return immediatly */
+
 	default:
 		device_printf(fdc->fdc_dev, "unexpected FD int->");
 		if (fd_read_status(fdc) == 0)
@@ -2195,8 +2172,8 @@ fdstate(fdc_p fdc)
 		printf("ST0 = %x, PCN = %x\n", st0, cyl);
 		return (0);
 	}
-	/*XXX confusing: some branches return immediately, others end up here*/
-	return (1); /* Come back immediatly to new state */
+	/* keep the compiler happy -- noone should ever get here */
+	return (999999);
 }
 
 static int
@@ -2228,33 +2205,27 @@ retrier(struct fdc_data *fdc)
 		break;
 	default:
 	fail:
-		{
-			int printerror = (fd->options & FDOPT_NOERRLOG) == 0;
-
-			if (printerror)
-				diskerr(bp, "hard error",
-				    fdc->fd->skip / DEV_BSIZE,
-				    (struct disklabel *)NULL);
-			if (printerror) {
-				if (fdc->flags & FDC_STAT_VALID)
-				{
-					printf(
+		if ((fd->options & FDOPT_NOERRLOG) == 0) {
+			diskerr(bp, "hard error", fdc->fd->skip / DEV_BSIZE,
+				(struct disklabel *)NULL);
+			if (fdc->flags & FDC_STAT_VALID) {
+				printf(
 				" (ST0 %b ST1 %b ST2 %b cyl %u hd %u sec %u)\n",
-					       fdc->status[0], NE7_ST0BITS,
-					       fdc->status[1], NE7_ST1BITS,
-					       fdc->status[2], NE7_ST2BITS,
-					       fdc->status[3], fdc->status[4],
-					       fdc->status[5]);
-				}
-				else
-					printf(" (No status)\n");
+				       fdc->status[0], NE7_ST0BITS,
+				       fdc->status[1], NE7_ST1BITS,
+				       fdc->status[2], NE7_ST2BITS,
+				       fdc->status[3], fdc->status[4],
+				       fdc->status[5]);
 			}
+			else
+				printf(" (No status)\n");
 		}
 		if ((fd->options & FDOPT_NOERROR) == 0) {
 			bp->bio_flags |= BIO_ERROR;
 			bp->bio_error = EIO;
-			bp->bio_resid += bp->bio_bcount - fdc->fd->skip;
-		}
+			bp->bio_resid = bp->bio_bcount - fdc->fd->skip;
+		} else
+			bp->bio_resid = 0;
 		fdc->bp = NULL;
 		fdc->fd->skip = 0;
 		device_unbusy(fd->dev);
@@ -2291,9 +2262,7 @@ fdmisccmd(dev_t dev, u_int cmd, void *data)
 	finfo = (struct fd_formb *)data;
 	idfield = (struct fdc_readid *)data;
 
-	bp = malloc(sizeof(struct bio), M_TEMP, M_ZERO | M_NOWAIT);
-	if (bp == 0)
-		return (ENOMEM);
+	bp = malloc(sizeof(struct bio), M_TEMP, M_ZERO);
 
 	/*
 	 * Set up a bio request for fdstrategy().  bio_blkno is faked
@@ -2324,12 +2293,12 @@ fdmisccmd(dev_t dev, u_int cmd, void *data)
 	bp->bio_flags = BIO_ORDERED;
 
 	/*
-	 * Now run the cmd.  The wait loop is a version of bufwait()
-	 * adapted for struct bio instead of struct buf and
-	 * specialized for the current context.
+	 * Now run the command.  The wait loop is a version of bufwait()
+	 * adapted for struct bio instead of struct buf and specialized
+	 * for the current context.
 	 */
 	fdstrategy(bp);
-	while((bp->bio_flags & BIO_DONE) == 0)
+	while ((bp->bio_flags & BIO_DONE) == 0)
 		tsleep(bp, PRIBIO, "fdcmd", 0);
 
 	free(bp, M_TEMP);
@@ -2342,79 +2311,65 @@ fdioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
  	fdu_t fdu;
  	fd_p fd;
 	struct fd_type *fdt;
-	struct disklabel *dl;
+	struct disklabel *lp;
 	struct fdc_status *fsp;
 	struct fdc_readid *rid;
-	char *buffer;
 	size_t fdblk;
-	int error = 0;
+	int error;
+
+ 	fdu = FDUNIT(minor(dev));
+ 	fd = devclass_get_softc(fd_devclass, fdu);
+
 
-	fdu = FDUNIT(minor(dev));
-	fd = devclass_get_softc(fd_devclass, fdu);
 	fdblk = 128 << fd->ft->secsize;
+	error = 0;
 
 	switch (cmd) {
 	case DIOCGDINFO:
-		buffer = malloc(DEV_BSIZE, M_TEMP, M_ZERO | M_NOWAIT);
-		if (buffer == 0) {
-			error = ENOMEM;
-			break;
-		}
-		dl = (struct disklabel *)buffer;
-		dl->d_secsize = fdblk;
+		lp = malloc(sizeof(*lp), M_TEMP, M_ZERO);
+		lp->d_secsize = fdblk;
 		fdt = fd->ft;
-		dl->d_secpercyl = fdt->size / fdt->tracks;
-		dl->d_type = DTYPE_FLOPPY;
-
-		if (readdisklabel(dkmodpart(dev, RAW_PART), dl)
-		    == NULL)
-			error = 0;
-		else
+		lp->d_secpercyl = fdt->size / fdt->tracks;
+		lp->d_type = DTYPE_FLOPPY;
+		if (readdisklabel(dkmodpart(dev, RAW_PART), lp) != NULL)
 			error = EINVAL;
-
-		*(struct disklabel *)addr = *dl;
-		free(buffer, M_TEMP);
+		else
+			*(struct disklabel *)addr = *lp;
+		free(lp, M_TEMP);
 		break;
 
 	case DIOCSDINFO:
 		if ((flag & FWRITE) == 0)
-			error = EBADF;
+			return (EBADF);
+		/*
+		 * XXX perhaps should call setdisklabel() to do error checking
+		 * although there is nowhere to "set" the result.  Perhaps
+		 * should always just fail.
+		 */
 		break;
 
 	case DIOCWLABEL:
 		if ((flag & FWRITE) == 0)
-			error = EBADF;
+			return (EBADF);
 		break;
 
 	case DIOCWDINFO:
-		if ((flag & FWRITE) == 0) {
-			error = EBADF;
-			break;
-		}
-
-		dl = (struct disklabel *)addr;
-
-		buffer = malloc(DEV_BSIZE, M_TEMP, M_ZERO | M_NOWAIT);
-		if (buffer == 0) {
-			error = ENOMEM;
-			break;
-		}
-		if ((error = setdisklabel((struct disklabel *)buffer, dl,
-					  (u_long)0)) != 0)
-			break;
-
-		error = writedisklabel(dev, (struct disklabel *)buffer);
-		free(buffer, M_TEMP);
+		if ((flag & FWRITE) == 0)
+			return (EBADF);
+		lp = malloc(DEV_BSIZE, M_TEMP, M_ZERO);
+		error = setdisklabel(lp, (struct disklabel *)addr, (u_long)0);
+		if (error != 0)
+			error = writedisklabel(dev, lp);
+		free(lp, M_TEMP);
 		break;
 
 	case FD_FORM:
 		if ((flag & FWRITE) == 0)
-			error = EBADF;	/* must be opened for writing */
-		else if (((struct fd_formb *)addr)->format_version !=
-			FD_FORMAT_VERSION)
-			error = EINVAL;	/* wrong version of formatting prog */
-		else
-			error = fdmisccmd(dev, BIO_FORMAT, addr);
+			return (EBADF);	/* must be opened for writing */
+		if (((struct fd_formb *)addr)->format_version !=
+		    FD_FORMAT_VERSION)
+			return (EINVAL); /* wrong version of formatting prog */
+		error = fdmisccmd(dev, BIO_FORMAT, addr);
 		break;
 
 	case FD_GTYPE:                  /* get drive type */
@@ -2424,7 +2379,7 @@ fdioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
 	case FD_STYPE:                  /* set drive type */
 		/* this is considered harmful; only allow for superuser */
 		if (suser(p) != 0)
-			return EPERM;
+			return (EPERM);
 		*fd->ft = *(struct fd_type *)addr;
 		break;
 
@@ -2444,21 +2399,21 @@ fdioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
 
 	case FD_CLRERR:
 		if (suser(p) != 0)
-			return EPERM;
+			return (EPERM);
 		fd->fdc->fdc_errs = 0;
 		break;
 
 	case FD_GSTAT:
 		fsp = (struct fdc_status *)addr;
 		if ((fd->fdc->flags & FDC_STAT_VALID) == 0)
-			return EINVAL;
+			return (EINVAL);
 		memcpy(fsp->status, fd->fdc->status, 7 * sizeof(u_int));
 		break;
 
 	case FD_READID:
 		rid = (struct fdc_readid *)addr;
 		if (rid->cyl > MAX_CYLINDER || rid->head > MAX_HEAD)
-			return EINVAL;
+			return (EINVAL);
 		error = fdmisccmd(dev, BIO_RDSECTID, addr);
 		break;