Add support for busmaster DMA on some PCI IDE chipsets.

I changed a few bits here and there, mainly renaming wd82371.c
to ide_pci.c now that it's supposed to handle different chipsets.

It runs on my P6 natoma board with two Maxtor drives, and also
on a Fujitsu machine I have at work with an Opti chipset and
a Quantum drive.

Submitted by:cgull@smoke.marlboro.vt.us <John Hood>

Original readme:

*** WARNING ***

This code has so far been tested on exactly one motherboard with two
identical drives known for their good DMA support.

This code, in the right circumstances, could corrupt data subtly,
silently, and invisibly, in much the same way that older PCI IDE
controllers do.  It's ALPHA-quality code; there's one or two major
gaps in my understanding of PCI IDE still.  Don't use this code on any
system with data that you care about; it's only good for hack boxes.
Expect that any data may be silently and randomly corrupted at any
moment.  It's a disk driver.  It has bugs.  Disk drivers with bugs
munch data.  It's a fact of life.

I also *STRONGLY* recommend getting a copy of your chipset's manual
and the ATA-2 or ATA-3 spec and making sure that timing modes on your
disk drives and IDE controller are being setup correctly by the BIOS--
because the driver makes only the lamest of attempts to do this just
now.

*** END WARNING ***

that said, i happen to think the code is working pretty well...

WHAT IT DOES:

this code adds support to the wd driver for bus mastering PCI IDE
controllers that follow the SFF-8038 standard.  (all the bus mastering
PCI IDE controllers i've seen so far do follow this standard.)  it
should provide busmastering on nearly any current P5 or P6 chipset,
specifically including any Intel chipset using one of the PIIX south
bridges-- this includes the '430FX, '430VX, '430HX, '430TX, '440LX,
and (i think) the Orion '450GX chipsets.  specific support is also
included for the VIA Apollo VP-1 chipset, as it appears in the
relabeled "HXPro" incarnation seen on cheap US$70 taiwanese
motherboards (that's what's in my development machine).  it works out
of the box on controllers that do DMA mode2; if my understanding is
correct, it'll probably work on Ultra-DMA33 controllers as well.
it'll probably work on busmastering IDE controllers in PCI slots, too,
but this is an area i am less sure about.

it cuts CPU usage considerably and improves drive performance
slightly.  usable numbers are difficult to come by with existing
benchmark tools, but experimentation on my K5-P90 system, with VIA
VP-1 chipset and Quantum Fireball 1080 drives, shows that disk i/o on
raw partitions imposes perhaps 5% cpu load.  cpu load during
filesystem i/o drops a lot, from near 100% to anywhere between 30% and
70%.  (the improvement may not be as large on an Intel chipset; from
what i can tell, the VIA VP-1 may not be very efficient with PCI I/O.)
disk performance improves by 5% or 10% with these drives.

real, visible, end-user performance improvement on a single user
machine is about nil. :) a kernel compile was sped up by a whole three
seconds.  it *does* feel a bit better-behaved when the system is
swapping heavily, but a better disk driver is not the fix for *that*
problem.

THE CODE:

this code is a patch to wd.c and wd82371.c, and associated header
files.  it should be considered alpha code; more work needs to be
done.

wd.c has fairly clean patches to add calls to busmaster code, as
implemented in wd82371.c and potentially elsewhere (one could imagine,
say, a Mac having a different DMA controller).

wd82371.c has been considerably reworked: the wddma interface that it
presents has been changed (expect more changes), many bugs have been
fixed, a new internal interface has been added for supporting
different chipsets, and the PCI probe has been considerably extended.

the interface between wd82371.c and wd.c is still fairly clean, but
i'm not sure it's in the right place.  there's a mess of issues around
ATA/ATAPI that need to be sorted out, including ATAPI support, CD-ROM
support, tape support, LS-120/Zip support, SFF-8038i DMA, UltraDMA,
PCI IDE controllers, bus probes, buggy controllers, controller timing
setup, drive timing setup, world peace and kitchen sinks.  whatever
happens with all this and however it gets partitioned, it is fairly
clear that wd.c needs some significant rework-- probably a complete
rewrite.

timing setup on disk controllers is something i've entirely punted on.
on my development machine, it appears that the BIOS does at least some
of the necessary timing setup.  i chose to restrict operation to
drives that are already configured for Mode4 PIO and Mode2 multiword
DMA, since the timing is essentially the same and many if not most
chipsets use the same control registers for DMA and PIO timing.

does anybody *know* whether BIOSes are required to do timing setup for
DMA modes on drives under their care?

error recovery is probably weak.  early on in development, i was
getting drive errors induced by bugs in the driver; i used these to
flush out the worst of the bugs in the driver's error handling, but
problems may remain.  i haven't got a drive with bad sectors i can
watch the driver flail on.

complaints about how wd82371.c has been reindented will be ignored
until the FreeBSD project has a real style policy, there is a
mechanism for individual authors to match it (indent flags or an emacs
c-mode or whatever), and it is enforced.  if i'm going to use a source
style i don't like, it would help if i could figure out what it *is*
(style(9) is about half of a policy), and a way to reasonably
duplicate it.  i ended up wasting a while trying to figure out what
the right thing to do was before deciding reformatting the whole thing
was the worst possible thing to do, except for all the other
possibilities.

i have maintained wd.c's indentation; that was not too hard,
fortunately.

TO INSTALL:

my dev box is freebsd 2.2.2 release.  fortunately, wd.c is a living
fossil, and has diverged very little recently.  included in this
tarball is a patch file, 'otherdiffs', for all files except wd82371.c,
my edited wd82371.c, a patch file, 'wd82371.c-diff-exact', against the
2.2.2 dist of 82371.c, and another patch file,
'wd82371.c-diff-whitespace', generated with diff -b (ignore
whitespace).  most of you not using 2.2.2 will probably have to use
this last patchfile with 'patch --ignore-whitespace'.  apply from the
kernel source tree root. as far as i can tell, this should apply
cleanly on anything from -current back to 2.2.2 and probably back to
2.2.0.  you, the kernel hacker, can figure out what to do from here.
if you need more specific directions, you probably should not be
experimenting with this code yet.

to enable DMA support, set flag 0x2000 for that drive in your config
file or in userconfig, as you would the 32-bit-PIO flag.  the driver
will then turn on DMA support if your drive and controller pass its
tests.  it's a bit picky, probably.  on discovering DMA mode failures
or disk errors or transfers that the DMA controller can't deal with,
the driver will fall back to PIO, so it is wise to setup the flags as
if PIO were still important.

'controller wdc0 at isa? port "IO_WD1" bio irq 14 flags 0xa0ffa0ff
vector wdintr' should work with nearly any PCI IDE controller.

i would *strongly* suggest booting single-user at first, and thrashing
the drive a bit while it's still mounted read-only.  this should be
fairly safe, even if the driver goes completely out to lunch.  it
might save you a reinstall.

one way to tell whether the driver is really using DMA is to check the
interrupt count during disk i/o with vmstat; DMA mode will add an
extremely low number of interrupts, as compared to even multi-sector
PIO.

boot -v will give you a copious register dump of timing-related info
on Intel and VIAtech chipsets, as well as PIO/DMA mode information on
all hard drives.  refer to your ATA and chipset documentation to
interpret these.

WHAT I'D LIKE FROM YOU and THINGS TO TEST:

reports.  success reports, failure reports, any kind of reports. :)
send them to cgull+ide@smoke.marlboro.vt.us.

i'd also like to see the kernel messages from various BIOSes (boot -v;
dmesg), along with info on the motherboard and BIOS on that machine.

i'm especially interested in reports on how this code works on the
various Intel chipsets, and whether the register dump works
correctly.  i'm also interested in hearing about other chipsets.

i'm especially interested in hearing success/failure reports for PCI
IDE controllers on cards, such as CMD's or Promise's new busmastering
IDE controllers.

UltraDMA-33 reports.

interoperation with ATAPI peripherals-- FreeBSD doesn't work with my
old Hitachi IDE CDROM, so i can't tell if I've broken anything. :)

i'd especially like to hear how the drive copes in DMA operation on
drives with bad sectors.  i haven't been able to find any such yet.

success/failure reports on older IDE drives with early support for DMA
modes-- those introduced between 1.5 and 3 years ago, typically
ranging from perhaps 400MB to 1.6GB.

failure reports on operation with more than one drive would be
appreciated.  the driver was developed with two drives on one
controller, the worst-case situation, and has been tested with one
drive on each controller, but you never know...

any reports of messages from the driver during normal operation,
especially "reverting to PIO mode", or "dmaverify odd vaddr or length"
(the DMA controller is strongly halfword oriented, and i'm curious to
know if any FreeBSD usage actually needs misaligned transfers).

performance reports.  beware that bonnie's CPU usage reporting is
useless for IDE drives; the best test i've found has been to run a
program that runs a spin loop at an idle priority and reports how many
iterations it manages, and even that sometimes produces numbers i
don't believe.  performance reports of multi-drive operation are
especially interesting; my system cannot sustain full throughput on
two drives on separate controllers, but that may just be a lame
motherboard.

THINGS I'M STILL MISSING CLUE ON:

* who's responsible for configuring DMA timing modes on IDE drives?
the BIOS or the driver?

* is there a spec for dealing with Ultra-DMA extensions?

* are there any chipsets or with bugs relating to DMA transfer that
should be blacklisted?

* are there any ATA interfaces that use some other kind of DMA
controller in conjunction with standard ATA protocol?

FINAL NOTE:

after having looked at the ATA-3 spec, all i can say is, "it's ugly".
*especially* electrically.  the IDE bus is best modeled as an
unterminated transmission line, these days.

for maximum reliability, keep your IDE cables as short as possible and
as few as possible.  from what i can tell, most current chipsets have
both IDE ports wired into a single buss, to a greater or lesser
degree.  using two cables means you double the length of this bus.

SCSI may have its warts, but at least the basic analog design of the
bus is still somewhat reasonable.  IDE passed beyond the veil two
years ago.

  --John Hood, cgull@smoke.marlboro.vt.us

3 files changed, 219 insertions, 14 deletions

diff --git a/sys/i386/conf/files.i386 b/sys/i386/conf/files.i386
index fe46c28..8a79192 100644
--- a/sys/i386/conf/files.i386
+++ b/sys/i386/conf/files.i386
@@ -1,7 +1,7 @@
 # This file tells config what files go into building a kernel,
 # files marked standard are always included.
 #
-#	$Id: files.i386,v 1.167 1997/07/24 23:45:17 fsmp Exp $
+#	$Id: files.i386,v 1.168 1997/07/25 11:53:20 phk Exp $
 #
 aic7xxx_asm			optional	ahc	device-driver	   \
 	dependency 	"$S/dev/aic7xxx/*.[chyl]"			   \
@@ -293,4 +293,4 @@ gnu/i386/fpemul/reg_u_sub.s	optional	gpl_math_emulate
 gnu/i386/fpemul/wm_shrx.s	optional	gpl_math_emulate
 gnu/i386/fpemul/wm_sqrt.s	optional	gpl_math_emulate
 gnu/i386/isa/dgb.c		optional	dgb	device-driver
-pci/wd82371.c			optional	wd	device-driver
+pci/ide_pci.c			optional	wd	device-driver
diff --git a/sys/i386/isa/wd.c b/sys/i386/isa/wd.c
index 09beae0..09231ad 100644
--- a/sys/i386/isa/wd.c
+++ b/sys/i386/isa/wd.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)wd.c	7.2 (Berkeley) 5/9/91
- *	$Id: wd.c,v 1.131 1997/07/01 00:22:45 bde Exp $
+ *	$Id: wd.c,v 1.132 1997/07/20 14:10:17 bde Exp $
  */
 
 /* TODO:
@@ -110,6 +110,7 @@ extern void wdstart(int ctrlr);
 				/* can't handle that in all cases */
 #define WDOPT_32BIT	0x8000
 #define WDOPT_SLEEPHACK	0x4000
+#define WDOPT_DMA	0x2000
 #define WDOPT_FORCEHD(x)	(((x)&0x0f00)>>8)
 #define WDOPT_MULTIMASK	0x00ff
 
@@ -173,12 +174,17 @@ struct disk {
 #define	DKFL_32BIT	0x00100	/* use 32-bit i/o mode */
 #define	DKFL_MULTI	0x00200	/* use multi-i/o mode */
 #define	DKFL_BADSCAN	0x00400	/* report all errors */
+#define DKFL_USEDMA	0x00800	/* use DMA for data transfers */
+#define DKFL_DMA	0x01000 /* using DMA on this transfer-- DKFL_SINGLE
+				 * overrides this
+				 */
 	struct wdparams dk_params; /* ESDI/IDE drive/controller parameters */
 	int	dk_dkunit;	/* disk stats unit number */
 	int	dk_multi;	/* multi transfers */
 	int	dk_currentiosize;	/* current io size */
 	struct diskgeom dk_dd;	/* device configuration data */
 	struct diskslices *dk_slices;	/* virtual drives */
+	void	*dk_dmacookie;	/* handle for DMA services */
 };
 
 #define WD_COUNT_RETRIES
@@ -215,6 +221,7 @@ static int wdsetctlr(struct disk *du);
 #if 0
 static int wdwsetctlr(struct disk *du);
 #endif
+static int wdsetmode(int mode, void *wdinfo);
 static int wdgetctlr(struct disk *du);
 static void wderror(struct buf *bp, struct disk *du, char *mesg);
 static void wdflushirq(struct disk *du, int old_ipl);
@@ -381,6 +388,7 @@ wdattach(struct isa_device *dvp)
 	int	unit, lunit;
 	struct isa_device *wdup;
 	struct disk *du;
+	struct wdparams *wp;
 
 	if (dvp->id_unit >= NWDC)
 		return (0);
@@ -443,6 +451,8 @@ wdattach(struct isa_device *dvp)
 				dvp->id_unit, unit, lunit,
 				sizeof du->dk_params.wdp_model,
 				du->dk_params.wdp_model);
+			if (du->dk_flags & DKFL_USEDMA)
+				printf(", DMA");
 			if (du->dk_flags & DKFL_32BIT)
 				printf(", 32-bit");
 			if (du->dk_multi > 1)
@@ -465,6 +475,17 @@ wdattach(struct isa_device *dvp)
 			       du->dk_dd.d_nsectors,
 			       du->dk_dd.d_secsize);
 
+			if (bootverbose) {
+			    wp = &du->dk_params;
+			    printf(
+"wd%d: ATA INQUIRE valid = %04x, dmamword = %04x, apio = %04x, udma = %04x\n",
+				du->dk_lunit,
+				wp->wdp_atavalid,
+				wp->wdp_dmamword,
+				wp->wdp_eidepiomodes,
+				wp->wdp_udmamode);
+			  }
+
 			/*
 			 * Start timeout routine for this drive.
 			 * XXX timeout should be per controller.
@@ -818,7 +839,19 @@ wdstart(int ctrlr)
 				count = 1;
 				du->dk_currentiosize = 1;
 			} else {
-				if( (count > 1) && (du->dk_multi > 1)) {
+				if((du->dk_flags & DKFL_USEDMA) &&
+				   wddma.wdd_dmaverify(du->dk_dmacookie,
+				   	(void *)((int)bp->b_un.b_addr + 
+					     du->dk_skip * DEV_BSIZE),
+					du->dk_bc,
+					bp->b_flags & B_READ)) {
+					du->dk_flags |= DKFL_DMA;
+					if( bp->b_flags & B_READ)
+						command = WDCC_READ_DMA;
+					else
+						command = WDCC_WRITE_DMA;
+					du->dk_currentiosize = count;
+				} else if( (count > 1) && (du->dk_multi > 1)) {
 					du->dk_flags |= DKFL_MULTI;
 					if( bp->b_flags & B_READ) {
 						command = WDCC_READ_MULTI;
@@ -854,6 +887,14 @@ wdstart(int ctrlr)
 		if(du->dk_dkunit >= 0) {
 			dk_busy |= 1 << du->dk_dkunit;
 		}
+
+		if ((du->dk_flags & (DKFL_DMA|DKFL_SINGLE)) == DKFL_DMA) {
+			wddma.wdd_dmaprep(du->dk_dmacookie,
+					   (void *)((int)bp->b_un.b_addr + 
+						    du->dk_skip * DEV_BSIZE),
+					   du->dk_bc,
+					   bp->b_flags & B_READ);
+		}
 		while (wdcommand(du, cylin, head, sector, count, command)
 		       != 0) {
 			wderror(bp, du,
@@ -884,6 +925,12 @@ wdstart(int ctrlr)
 	 */
 	du->dk_timeout = 1 + 3;
 
+	/* if this is a DMA op, start DMA and go away until it's done. */
+	if ((du->dk_flags & (DKFL_DMA|DKFL_SINGLE)) == DKFL_DMA) {
+		wddma.wdd_dmastart(du->dk_dmacookie);
+		return;
+	}
+
 	/* If this is a read operation, just go away until it's done. */
 	if (bp->b_flags & B_READ)
 		return;
@@ -988,6 +1035,15 @@ wdintr(int unit)
 	du = wddrives[dkunit(bp->b_dev)];
 	du->dk_timeout = 0;
 
+	/* finish off DMA. ignore errors if we're not using it. */
+	if (du->dk_flags & (DKFL_DMA|DKFL_USEDMA)) {
+		if ((wddma.wdd_dmadone(du->dk_dmacookie) != WDDS_INTERRUPT) &&
+		    !(du->dk_flags & DKFL_USEDMA)) {
+			wderror(bp, du, "wdintr: DMA failure");
+			du->dk_status |= WDCS_ERR; /* XXX totally bogus err */
+		}
+	}
+
 	if (wdwait(du, 0, TIMEOUT) < 0) {
 		wderror(bp, du, "wdintr: timeout waiting for status");
 		du->dk_status |= WDCS_ERR;	/* XXX */
@@ -1014,7 +1070,12 @@ oops:
 		 * XXX bogus inb() here, register 0 is assumed and intr status
 		 * is reset.
 		 */
-		if( (du->dk_flags & DKFL_MULTI) && (inb(du->dk_port) & WDERR_ABORT)) {
+		if((du->dk_flags & DKFL_DMA ) &&
+		   (inb(du->dk_port) & WDERR_ABORT)) {
+			wderror(bp, du, "reverting to PIO mode");
+			du->dk_flags |= ~DKFL_USEDMA;
+		} else if((du->dk_flags & DKFL_MULTI) &&
+                    (inb(du->dk_port) & WDERR_ABORT)) {
 			wderror(bp, du, "reverting to non-multi sector mode");
 			du->dk_multi = 1;
 		}
@@ -1052,6 +1113,7 @@ oops:
 	 * If this was a successful read operation, fetch the data.
 	 */
 	if (((bp->b_flags & (B_READ | B_ERROR)) == B_READ)
+            && !(du->dk_flags & DKFL_DMA)
 	    && wdtab[unit].b_active) {
 		int	chk, dummy, multisize;
 		multisize = chk = du->dk_currentiosize * DEV_BSIZE;
@@ -1093,6 +1155,20 @@ oops:
 			dk_wds[du->dk_dkunit] += chk >> 6;
 	}
 
+	/* final cleanup on DMA */
+	if (((bp->b_flags & B_ERROR) == 0)
+            && (du->dk_flags & DKFL_DMA)
+	    && wdtab[unit].b_active) {
+		int iosize;
+
+		iosize = du->dk_currentiosize * DEV_BSIZE;
+
+		du->dk_bc -= iosize;
+
+		if (du->dk_dkunit >= 0)
+			dk_wds[du->dk_dkunit] += iosize >> 6;
+	}
+
 outt:
 	if (wdtab[unit].b_active) {
 		if ((bp->b_flags & B_ERROR) == 0) {
@@ -1124,7 +1200,7 @@ outt:
 
 done: ;
 		/* done with this transfer, with or without error */
-		du->dk_flags &= ~DKFL_SINGLE;
+		du->dk_flags &= ~(DKFL_SINGLE|DKFL_DMA);
 		TAILQ_REMOVE(&wdtab[unit].controller_queue, bp, b_act);
 		wdtab[unit].b_errcnt = 0;
 		bp->b_resid = bp->b_bcount - du->dk_skip * DEV_BSIZE;
@@ -1441,7 +1517,7 @@ wdcommand(struct disk *du, u_int cylinder, u_int head, u_int sector,
 		outb(wdc + wd_sector, sector + 1);
 		outb(wdc + wd_seccnt, count);
 	}
-	if (wdwait(du, command == WDCC_DIAGNOSE || command == WDCC_IDC
+	if (wdwait(du, (command == WDCC_DIAGNOSE || command == WDCC_IDC)
 		       ? 0 : WDCS_READY, TIMEOUT) < 0)
 		return (1);
 	outb(wdc + wd_command, command);
@@ -1557,6 +1633,25 @@ wdwsetctlr(struct disk *du)
 #endif
 
 /*
+ * gross little callback function for wdddma interface. returns 1 for
+ * success, 0 for failure.
+ */
+static int
+wdsetmode(int mode, void *wdinfo)
+{
+    int i;
+    struct disk *du;
+
+    du = wdinfo;
+    if (bootverbose)
+	printf("wdsetmode() setting transfer mode to %02x\n", mode);
+    i = wdcommand(du, 0, 0, mode, WDFEA_SETXFER, 
+		  WDCC_FEATURES) == 0 &&
+	wdwait(du, WDCS_READY, TIMEOUT) == 0;
+    return i;
+}
+
+/*
  * issue READP to drive to ask it what it is.
  */
 static int
@@ -1711,6 +1806,21 @@ failed:
 	du->dk_multi = wp->wdp_nsecperint & 0xff;
 	wdsetmulti(du);
 
+	du->dk_dmacookie = NULL;
+	/*
+	 * check drive's DMA capability
+	 */
+	/* does user want this? */
+	if ((du->cfg_flags & WDOPT_DMA) &&
+	    /* have we got a DMA controller? */
+	    (wddma.wdd_candma &&
+	     (du->dk_dmacookie = wddma.wdd_candma(du->dk_port,
+						  du->dk_unit))) &&
+	    /* can said drive do DMA? */
+	    (wddma.wdd_dmainit(du->dk_dmacookie, wp, wdsetmode, du)))
+
+	    du->dk_flags |= DKFL_USEDMA;
+
 #ifdef WDDEBUG
 	printf(
 "\nwd(%d,%d): wdgetctlr: gc %x cyl %d trk %d sec %d type %d sz %d model %s\n",
@@ -2061,6 +2171,9 @@ wdreset(struct disk *du)
 {
 	int     wdc, err = 0;
 
+	if ((du->dk_flags & (DKFL_DMA|DKFL_USEDMA)) && du->dk_dmacookie)
+		wddma.wdd_dmadone(du->dk_dmacookie);
+
 	wdc = du->dk_port;
 	(void)wdwait(du, 0, TIMEOUT);
 	outb(wdc + wd_ctlr, WDCTL_IDS | WDCTL_RST);
@@ -2112,7 +2225,7 @@ wdtimeout(void *cdu)
 		if(timeouts++ == 5)
 			wderror((struct buf *)NULL, du,
    "Last time I say: interrupt timeout.  Probably a portable PC.");
-		else if(timeouts++ < 5)
+		else if(timeouts < 5)
 			wderror((struct buf *)NULL, du, "interrupt timeout");
 		wdunwedge(du);
 		wdflushirq(du, x);
diff --git a/sys/i386/isa/wdreg.h b/sys/i386/isa/wdreg.h
index 3ad2403..f7dfa488 100644
--- a/sys/i386/isa/wdreg.h
+++ b/sys/i386/isa/wdreg.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)wdreg.h	7.1 (Berkeley) 5/9/91
- *	$Id$
+ *	$Id: wdreg.h,v 1.17 1997/02/22 09:37:27 peter Exp $
  */
 
 /*
@@ -122,6 +122,8 @@
 #define WDCC_READ_MULTI	0xC4	/* read multiple */
 #define WDCC_WRITE_MULTI	0xC5	/* write multiple */
 #define WDCC_SET_MULTI 0xC6		/* set multiple count */
+#define WDCC_READ_DMA	0xC8		/* read using DMA */
+#define WDCC_WRITE_DMA	0xCA		/* write using DMA */
 
 
 #define	WDCC_EXTDCMD	0xE0		/* send extended command */
@@ -130,6 +132,7 @@
 
 #define	WDFEA_RCACHE	0xAA		/* read cache enable */
 #define WDFEA_WCACHE	0x02		/* write cache enable */
+#define WDFEA_SETXFER	0x03		/* set transfer mode */
 
 #define	WD_STEP		0		/* winchester- default 35us step */
 
@@ -140,10 +143,14 @@
  * read parameters command returns this:
  */
 struct wdparams {
+	/*
+	 * XXX partly based on DRAFT X3T13/1153D rev 14.  
+	 * by the time you read this it will have changed.
+	 */
 	/* drive info */
 	short	wdp_config;		/* general configuration bits */
 	u_short	wdp_cylinders;		/* number of cylinders */
-	short	wdp_reserved;
+	short	wdp_reserved2;
 	u_short	wdp_heads;		/* number of heads */
 	short	wdp_unfbytespertrk;	/* number of unformatted bytes/track */
 	short	wdp_unfbytes;		/* number of unformatted bytes/sector */
@@ -159,8 +166,58 @@ struct wdparams {
 	short	wdp_necc;		/* ecc bytes appended */
 	char	wdp_rev[8];		/* firmware revision */
 	char	wdp_model[40];		/* model name */
-	short	wdp_nsecperint;		/* sectors per interrupt */
+	char	wdp_nsecperint;		/* sectors per interrupt */
+	char	wdp_vendorunique1;
 	short	wdp_usedmovsd;		/* can use double word read/write? */
+	char	wdp_vendorunique2;
+	char	wdp_capability;		/* various capability bits */
+	short	wdp_cap_validate;	/* validation for above */
+	char	wdp_vendorunique3;
+	char	wdp_opiomode;		/* PIO modes 0-2 */
+	char	wdp_vendorunique4;
+	char	wdp_odmamode;		/* old DMA modes, not in ATA-3 */
+	short	wdp_atavalid;		/* validation for newer fields */
+	short	wdp_currcyls;
+	short	wdp_currheads;
+	short	wdp_currsectors;
+	short	wdp_currsize0;
+	short	wdp_currsize1;
+	char	wdp_currmultsect;
+	char	wdp_multsectvalid;
+	int	wdp_lbasize;
+	short	wdp_dmasword;		/* obsolete in ATA-3 */
+	short	wdp_dmamword;		/* multiword DMA modes */
+	short	wdp_eidepiomodes;	/* advanced PIO modes */
+	short	wdp_eidedmamin;		/* fastest possible DMA timing */
+	short	wdp_eidedmanorm;	/* recommended DMA timing */
+	short	wdp_eidepioblind;	/* fastest possible blind PIO */
+	short	wdp_eidepioacked;	/* fastest possible IORDY PIO */
+	short	wdp_reserved69;
+	short	wdp_reserved70;
+	short	wdp_reserved71;
+	short	wdp_reserved72;
+	short	wdp_reserved73;
+	short	wdp_reserved74;
+	short	wdp_queuelen;
+	short	wdp_reserved76;
+	short	wdp_reserved77;
+	short	wdp_reserved78;
+	short	wdp_reserved79;
+	short	wdp_versmaj;
+	short	wdp_versmin;
+	short	wdp_featsupp1;
+	short	wdp_featsupp2;
+	short	wdp_featsupp3;
+	short	wdp_featenab1;
+	short	wdp_featenab2;
+	short	wdp_featenab3;
+	short	wdp_udmamode;		/* UltraDMA modes */
+	short	wdp_erasetime;
+	short	wdp_enherasetime;
+	short	wdp_apmlevel;
+	short	wdp_reserved92[34];
+	short	wdp_rmvcap;
+	short	wdp_securelevel;
 };
 
 /*
@@ -179,12 +236,18 @@ int wdformat(struct buf *bp);
  * To use this:
  *	For each drive which you might want to do DMA on, call wdd_candma()
  *	to get a cookie.  If it returns a null pointer, then the drive
- *	can't do DMA.
+ *	can't do DMA.  Then call wdd_dmainit() to initialize the controller
+ *	and drive.  wdd_dmainit should leave PIO modes operational, though
+ *	perhaps with suboptimal performance.
  *
- *	Set up the transfer be calling wdd_dmaprep().  The cookie is what
+ *	Check the transfer by calling wdd_dmaverify().  The cookie is what
  *	you got before; vaddr is the virtual address of the buffer to be
  *	written; len is the length of the buffer; and direction is either
- *	B_READ or B_WRITE.
+ *	B_READ or B_WRITE. This function verifies that the DMA hardware is
+ *	capable of handling the request you've made.
+ *
+ *	Setup the transfer by calling wdd_dmaprep().  This takes the same
+ *	paramaters as wdd_dmaverify().
  *
  *	Send a read/write DMA command to the drive.
  *
@@ -199,6 +262,8 @@ int wdformat(struct buf *bp);
 struct wddma {
 	void	*(*wdd_candma)		/* returns a cookie if can do DMA */
 		__P((int ctlr, int drive));
+	int	(*wdd_dmaverify)	/* verify that request is DMA-able */
+		__P((void *cookie, char *vaddr, u_long len, int direction));
 	int	(*wdd_dmaprep)		/* prepare DMA hardware */
 		__P((void *cookie, char *vaddr, u_long len, int direction));
 	void	(*wdd_dmastart)		/* begin DMA transfer */
@@ -207,12 +272,39 @@ struct wddma {
 		__P((void *cookie));
 	int	(*wdd_dmastatus)	/* return status of DMA */
 		__P((void *cookie));
+	int	(*wdd_dmainit)		/* initialize controller and drive */
+		__P((void *cookie, 
+		     struct wdparams *wp, 
+		     int(wdcmd)__P((int mode, void *wdinfo)),
+		     void *wdinfo));
 };
 
+/* logical status bits returned by wdd_dmastatus */
 #define	WDDS_ACTIVE	0x0001
 #define	WDDS_ERROR	0x0002
 #define	WDDS_INTERRUPT	0x0004
 
+#if 0
+/* XXX are these now useless? */
+/* local defines for ATA timing modes */
+#define WDDMA_GRPMASK	0xf0
+/* flow-controlled PIO modes */
+#define	WDDMA_PIO	0x10
+#define WDDMA_PIO3	0x10
+#define WDDMA_PIO4	0x11
+/* multi-word DMA timing modes */
+#define	WDDMA_MDMA	0x20
+#define	WDDMA_MDMA0	0x20
+#define	WDDMA_MDMA1	0x21
+#define	WDDMA_MDMA2	0x22
+
+/* Ultra DMA timing modes */
+#define	WDDMA_UDMA	0x30
+#define	WDDMA_UDMA0	0x30
+#define	WDDMA_UDMA1	0x31
+#define	WDDMA_UDMA2	0x32
+#endif
+
 extern struct wddma wddma;
 
 #endif /* KERNEL */