Import sources from 2011-03-30 iso image

1 files changed, 2304 insertions, 0 deletions

diff --git a/sys/src/9/pc/sdata.c b/sys/src/9/pc/sdata.c
new file mode 100755
index 000000000..21b289db9
--- /dev/null
+++ b/sys/src/9/pc/sdata.c
@@ -0,0 +1,2304 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "io.h"
+#include "ureg.h"
+#include "../port/error.h"
+
+#include "../port/sd.h"
+
+#define	HOWMANY(x, y)	(((x)+((y)-1))/(y))
+#define ROUNDUP(x, y)	(HOWMANY((x), (y))*(y))
+
+extern SDifc sdataifc;
+
+enum {
+	DbgCONFIG	= 0x0001,	/* detected drive config info */
+	DbgIDENTIFY	= 0x0002,	/* detected drive identify info */
+	DbgSTATE	= 0x0004,	/* dump state on panic */
+	DbgPROBE	= 0x0008,	/* trace device probing */
+	DbgDEBUG	= 0x0080,	/* the current problem... */
+	DbgINL		= 0x0100,	/* That Inil20+ message we hate */
+	Dbg48BIT	= 0x0200,	/* 48-bit LBA */
+	DbgBsy		= 0x0400,	/* interrupt but Bsy (shared IRQ) */
+};
+#define DEBUG		(DbgDEBUG|DbgSTATE)
+
+enum {					/* I/O ports */
+	Data		= 0,
+	Error		= 1,		/* (read) */
+	Features	= 1,		/* (write) */
+	Count		= 2,		/* sector count<7-0>, sector count<15-8> */
+	Ir		= 2,		/* interrupt reason (PACKET) */
+	Sector		= 3,		/* sector number */
+	Lbalo		= 3,		/* LBA<7-0>, LBA<31-24> */
+	Cyllo		= 4,		/* cylinder low */
+	Bytelo		= 4,		/* byte count low (PACKET) */
+	Lbamid		= 4,		/* LBA<15-8>, LBA<39-32> */
+	Cylhi		= 5,		/* cylinder high */
+	Bytehi		= 5,		/* byte count hi (PACKET) */
+	Lbahi		= 5,		/* LBA<23-16>, LBA<47-40> */
+	Dh		= 6,		/* Device/Head, LBA<27-24> */
+	Status		= 7,		/* (read) */
+	Command		= 7,		/* (write) */
+
+	As		= 2,		/* Alternate Status (read) */
+	Dc		= 2,		/* Device Control (write) */
+};
+
+enum {					/* Error */
+	Med		= 0x01,		/* Media error */
+	Ili		= 0x01,		/* command set specific (PACKET) */
+	Nm		= 0x02,		/* No Media */
+	Eom		= 0x02,		/* command set specific (PACKET) */
+	Abrt		= 0x04,		/* Aborted command */
+	Mcr		= 0x08,		/* Media Change Request */
+	Idnf		= 0x10,		/* no user-accessible address */
+	Mc		= 0x20,		/* Media Change */
+	Unc		= 0x40,		/* Uncorrectable data error */
+	Wp		= 0x40,		/* Write Protect */
+	Icrc		= 0x80,		/* Interface CRC error */
+};
+
+enum {					/* Features */
+	Dma		= 0x01,		/* data transfer via DMA (PACKET) */
+	Ovl		= 0x02,		/* command overlapped (PACKET) */
+};
+
+enum {					/* Interrupt Reason */
+	Cd		= 0x01,		/* Command/Data */
+	Io		= 0x02,		/* I/O direction */
+	Rel		= 0x04,		/* Bus Release */
+};
+
+enum {					/* Device/Head */
+	Dev0		= 0xA0,		/* Master */
+	Dev1		= 0xB0,		/* Slave */
+	Lba		= 0x40,		/* LBA mode */
+};
+
+enum {					/* Status, Alternate Status */
+	Err		= 0x01,		/* Error */
+	Chk		= 0x01,		/* Check error (PACKET) */
+	Drq		= 0x08,		/* Data Request */
+	Dsc		= 0x10,		/* Device Seek Complete */
+	Serv		= 0x10,		/* Service */
+	Df		= 0x20,		/* Device Fault */
+	Dmrd		= 0x20,		/* DMA ready (PACKET) */
+	Drdy		= 0x40,		/* Device Ready */
+	Bsy		= 0x80,		/* Busy */
+};
+
+enum {					/* Command */
+	Cnop		= 0x00,		/* NOP */
+	Cdr		= 0x08,		/* Device Reset */
+	Crs		= 0x20,		/* Read Sectors */
+	Crs48		= 0x24,		/* Read Sectors Ext */
+	Crd48		= 0x25,		/* Read w/ DMA Ext */
+	Crdq48		= 0x26,		/* Read w/ DMA Queued Ext */
+	Crsm48		= 0x29,		/* Read Multiple Ext */
+	Cws		= 0x30,		/* Write Sectors */
+	Cws48		= 0x34,		/* Write Sectors Ext */
+	Cwd48		= 0x35,		/* Write w/ DMA Ext */
+	Cwdq48		= 0x36,		/* Write w/ DMA Queued Ext */
+	Cwsm48		= 0x39,		/* Write Multiple Ext */
+	Cedd		= 0x90,		/* Execute Device Diagnostics */
+	Cpkt		= 0xA0,		/* Packet */
+	Cidpkt		= 0xA1,		/* Identify Packet Device */
+	Crsm		= 0xC4,		/* Read Multiple */
+	Cwsm		= 0xC5,		/* Write Multiple */
+	Csm		= 0xC6,		/* Set Multiple */
+	Crdq		= 0xC7,		/* Read DMA queued */
+	Crd		= 0xC8,		/* Read DMA */
+	Cwd		= 0xCA,		/* Write DMA */
+	Cwdq		= 0xCC,		/* Write DMA queued */
+	Cstandby	= 0xE2,		/* Standby */
+	Cid		= 0xEC,		/* Identify Device */
+	Csf		= 0xEF,		/* Set Features */
+};
+
+enum {					/* Device Control */
+	Nien		= 0x02,		/* (not) Interrupt Enable */
+	Srst		= 0x04,		/* Software Reset */
+	Hob		= 0x80,		/* High Order Bit [sic] */
+};
+
+enum {					/* PCI Configuration Registers */
+	Bmiba		= 0x20,		/* Bus Master Interface Base Address */
+	Idetim		= 0x40,		/* IE Timing */
+	Sidetim		= 0x44,		/* Slave IE Timing */
+	Udmactl		= 0x48,		/* Ultra DMA/33 Control */
+	Udmatim		= 0x4A,		/* Ultra DMA/33 Timing */
+};
+
+enum {					/* Bus Master IDE I/O Ports */
+	Bmicx		= 0,		/* Command */
+	Bmisx		= 2,		/* Status */
+	Bmidtpx		= 4,		/* Descriptor Table Pointer */
+};
+
+enum {					/* Bmicx */
+	Ssbm		= 0x01,		/* Start/Stop Bus Master */
+	Rwcon		= 0x08,		/* Read/Write Control */
+};
+
+enum {					/* Bmisx */
+	Bmidea		= 0x01,		/* Bus Master IDE Active */
+	Idedmae		= 0x02,		/* IDE DMA Error  (R/WC) */
+	Ideints		= 0x04,		/* IDE Interrupt Status (R/WC) */
+	Dma0cap		= 0x20,		/* Drive 0 DMA Capable */
+	Dma1cap		= 0x40,		/* Drive 0 DMA Capable */
+};
+enum {					/* Physical Region Descriptor */
+	PrdEOT		= 0x80000000,	/* End of Transfer */
+};
+
+enum {					/* offsets into the identify info. */
+	Iconfig		= 0,		/* general configuration */
+	Ilcyl		= 1,		/* logical cylinders */
+	Ilhead		= 3,		/* logical heads */
+	Ilsec		= 6,		/* logical sectors per logical track */
+	Iserial		= 10,		/* serial number */
+	Ifirmware	= 23,		/* firmware revision */
+	Imodel		= 27,		/* model number */
+	Imaxrwm		= 47,		/* max. read/write multiple sectors */
+	Icapabilities	= 49,		/* capabilities */
+	Istandby	= 50,		/* device specific standby timer */
+	Ipiomode	= 51,		/* PIO data transfer mode number */
+	Ivalid		= 53,
+	Iccyl		= 54,		/* cylinders if (valid&0x01) */
+	Ichead		= 55,		/* heads if (valid&0x01) */
+	Icsec		= 56,		/* sectors if (valid&0x01) */
+	Iccap		= 57,		/* capacity if (valid&0x01) */
+	Irwm		= 59,		/* read/write multiple */
+	Ilba		= 60,		/* LBA size */
+	Imwdma		= 63,		/* multiword DMA mode */
+	Iapiomode	= 64,		/* advanced PIO modes supported */
+	Iminmwdma	= 65,		/* min. multiword DMA cycle time */
+	Irecmwdma	= 66,		/* rec. multiword DMA cycle time */
+	Iminpio		= 67,		/* min. PIO cycle w/o flow control */
+	Iminiordy	= 68,		/* min. PIO cycle with IORDY */
+	Ipcktbr		= 71,		/* time from PACKET to bus release */
+	Iserbsy		= 72,		/* time from SERVICE to !Bsy */
+	Iqdepth		= 75,		/* max. queue depth */
+	Imajor		= 80,		/* major version number */
+	Iminor		= 81,		/* minor version number */
+	Icsfs		= 82,		/* command set/feature supported */
+	Icsfe		= 85,		/* command set/feature enabled */
+	Iudma		= 88,		/* ultra DMA mode */
+	Ierase		= 89,		/* time for security erase */
+	Ieerase		= 90,		/* time for enhanced security erase */
+	Ipower		= 91,		/* current advanced power management */
+	Ilba48		= 100,		/* 48-bit LBA size (64 bits in 100-103) */
+	Irmsn		= 127,		/* removable status notification */
+	Isecstat	= 128,		/* security status */
+	Icfapwr		= 160,		/* CFA power mode */
+	Imediaserial	= 176,		/* current media serial number */
+	Icksum		= 255,		/* checksum */
+};
+
+enum {					/* bit masks for config identify info */
+	Mpktsz		= 0x0003,	/* packet command size */
+	Mincomplete	= 0x0004,	/* incomplete information */
+	Mdrq		= 0x0060,	/* DRQ type */
+	Mrmdev		= 0x0080,	/* device is removable */
+	Mtype		= 0x1F00,	/* device type */
+	Mproto		= 0x8000,	/* command protocol */
+};
+
+enum {					/* bit masks for capabilities identify info */
+	Mdma		= 0x0100,	/* DMA supported */
+	Mlba		= 0x0200,	/* LBA supported */
+	Mnoiordy	= 0x0400,	/* IORDY may be disabled */
+	Miordy		= 0x0800,	/* IORDY supported */
+	Msoftrst	= 0x1000,	/* needs soft reset when Bsy */
+	Mstdby		= 0x2000,	/* standby supported */
+	Mqueueing	= 0x4000,	/* queueing overlap supported */
+	Midma		= 0x8000,	/* interleaved DMA supported */
+};
+
+enum {					/* bit masks for supported/enabled features */
+	Msmart		= 0x0001,
+	Msecurity	= 0x0002,
+	Mrmmedia	= 0x0004,
+	Mpwrmgmt	= 0x0008,
+	Mpkt		= 0x0010,
+	Mwcache		= 0x0020,
+	Mlookahead	= 0x0040,
+	Mrelirq		= 0x0080,
+	Msvcirq		= 0x0100,
+	Mreset		= 0x0200,
+	Mprotected	= 0x0400,
+	Mwbuf		= 0x1000,
+	Mrbuf		= 0x2000,
+	Mnop		= 0x4000,
+	Mmicrocode	= 0x0001,
+	Mqueued		= 0x0002,
+	Mcfa		= 0x0004,
+	Mapm		= 0x0008,
+	Mnotify		= 0x0010,
+	Mstandby	= 0x0020,
+	Mspinup		= 0x0040,
+	Mmaxsec		= 0x0100,
+	Mautoacoustic	= 0x0200,
+	Maddr48		= 0x0400,
+	Mdevconfov	= 0x0800,
+	Mflush		= 0x1000,
+	Mflush48	= 0x2000,
+	Msmarterror	= 0x0001,
+	Msmartselftest	= 0x0002,
+	Mmserial	= 0x0004,
+	Mmpassthru	= 0x0008,
+	Mlogging	= 0x0020,
+};
+
+typedef struct Ctlr Ctlr;
+typedef struct Drive Drive;
+
+typedef struct Prd {			/* Physical Region Descriptor */
+	ulong	pa;			/* Physical Base Address */
+	int	count;
+} Prd;
+
+enum {
+	BMspan		= 64*1024,	/* must be power of 2 <= 64*1024 */
+
+	Nprd		= SDmaxio/BMspan+2,
+};
+
+typedef struct Ctlr {
+	int	cmdport;
+	int	ctlport;
+	int	irq;
+	int	tbdf;
+	int	bmiba;			/* bus master interface base address */
+	int	maxio;			/* sector count transfer maximum */
+	int	span;			/* don't span this boundary with dma */
+
+	Pcidev*	pcidev;
+	void	(*ienable)(Ctlr*);
+	void	(*idisable)(Ctlr*);
+	SDev*	sdev;
+
+	Drive*	drive[2];
+
+	Prd*	prdt;			/* physical region descriptor table */
+
+	QLock;				/* current command */
+	Drive*	curdrive;
+	int	command;		/* last command issued (debugging) */
+	Rendez;
+	int	done;
+
+	Lock;				/* register access */
+} Ctlr;
+
+typedef struct Drive {
+	Ctlr*	ctlr;
+
+	int	dev;
+	ushort	info[256];
+	int	c;			/* cylinder */
+	int	h;			/* head */
+	int	s;			/* sector */
+	vlong	sectors;		/* total */
+	int	secsize;		/* sector size */
+
+	int	dma;			/* DMA R/W possible */
+	int	dmactl;
+	int	rwm;			/* read/write multiple possible */
+	int	rwmctl;
+
+	int	pkt;			/* PACKET device, length of pktcmd */
+	uchar	pktcmd[16];
+	int	pktdma;			/* this PACKET command using dma */
+
+	uchar	sense[18];
+	uchar	inquiry[48];
+
+	QLock;				/* drive access */
+	int	command;		/* current command */
+	int	write;
+	uchar*	data;
+	int	dlen;
+	uchar*	limit;
+	int	count;			/* sectors */
+	int	block;			/* R/W bytes per block */
+	int	status;
+	int	error;
+	int	flags;			/* internal flags */
+} Drive;
+
+enum {					/* internal flags */
+	Lba48		= 0x1,		/* LBA48 mode */
+	Lba48always	= 0x2,		/* ... */
+};
+enum {
+	Last28		= (1<<28) - 1 - 1, /* all-ones mask is not addressible */
+};
+
+static void
+pc87415ienable(Ctlr* ctlr)
+{
+	Pcidev *p;
+	int x;
+
+	p = ctlr->pcidev;
+	if(p == nil)
+		return;
+
+	x = pcicfgr32(p, 0x40);
+	if(ctlr->cmdport == p->mem[0].bar)
+		x &= ~0x00000100;
+	else
+		x &= ~0x00000200;
+	pcicfgw32(p, 0x40, x);
+}
+
+static void
+atadumpstate(Drive* drive, uchar* cmd, vlong lba, int count)
+{
+	Prd *prd;
+	Pcidev *p;
+	Ctlr *ctlr;
+	int i, bmiba;
+
+	if(!(DEBUG & DbgSTATE)){
+		USED(drive, cmd, lba, count);
+		return;
+	}
+
+	ctlr = drive->ctlr;
+	print("sdata: command %2.2uX\n", ctlr->command);
+	print("data %8.8p limit %8.8p dlen %d status %uX error %uX\n",
+		drive->data, drive->limit, drive->dlen,
+		drive->status, drive->error);
+	if(cmd != nil){
+		print("lba %d -> %lld, count %d -> %d (%d)\n",
+			(cmd[2]<<24)|(cmd[3]<<16)|(cmd[4]<<8)|cmd[5], lba,
+			(cmd[7]<<8)|cmd[8], count, drive->count);
+	}
+	if(!(inb(ctlr->ctlport+As) & Bsy)){
+		for(i = 1; i < 7; i++)
+			print(" 0x%2.2uX", inb(ctlr->cmdport+i));
+		print(" 0x%2.2uX\n", inb(ctlr->ctlport+As));
+	}
+	if(drive->command == Cwd || drive->command == Crd){
+		bmiba = ctlr->bmiba;
+		prd = ctlr->prdt;
+		print("bmicx %2.2uX bmisx %2.2uX prdt %8.8p\n",
+			inb(bmiba+Bmicx), inb(bmiba+Bmisx), prd);
+		for(;;){
+			print("pa 0x%8.8luX count %8.8uX\n",
+				prd->pa, prd->count);
+			if(prd->count & PrdEOT)
+				break;
+			prd++;
+		}
+	}
+	if(ctlr->pcidev && ctlr->pcidev->vid == 0x8086){
+		p = ctlr->pcidev;
+		print("0x40: %4.4uX 0x42: %4.4uX",
+			pcicfgr16(p, 0x40), pcicfgr16(p, 0x42));
+		print("0x48: %2.2uX\n", pcicfgr8(p, 0x48));
+		print("0x4A: %4.4uX\n", pcicfgr16(p, 0x4A));
+	}
+}
+
+static int
+atadebug(int cmdport, int ctlport, char* fmt, ...)
+{
+	int i, n;
+	va_list arg;
+	char buf[PRINTSIZE];
+
+	if(!(DEBUG & DbgPROBE)){
+		USED(cmdport, ctlport, fmt);
+		return 0;
+	}
+
+	va_start(arg, fmt);
+	n = vseprint(buf, buf+sizeof(buf), fmt, arg) - buf;
+	va_end(arg);
+
+	if(cmdport){
+		if(buf[n-1] == '\n')
+			n--;
+		n += snprint(buf+n, PRINTSIZE-n, " ataregs 0x%uX:",
+			cmdport);
+		for(i = Features; i < Command; i++)
+			n += snprint(buf+n, PRINTSIZE-n, " 0x%2.2uX",
+				inb(cmdport+i));
+		if(ctlport)
+			n += snprint(buf+n, PRINTSIZE-n, " 0x%2.2uX",
+				inb(ctlport+As));
+		n += snprint(buf+n, PRINTSIZE-n, "\n");
+	}
+	putstrn(buf, n);
+
+	return n;
+}
+
+static int
+ataready(int cmdport, int ctlport, int dev, int reset, int ready, int micro)
+{
+	int as;
+
+	atadebug(cmdport, ctlport, "ataready: dev %uX reset %uX ready %uX",
+		dev, reset, ready);
+
+	for(;;){
+		/*
+		 * Wait for the controller to become not busy and
+		 * possibly for a status bit to become true (usually
+		 * Drdy). Must change to the appropriate device
+		 * register set if necessary before testing for ready.
+		 * Always run through the loop at least once so it
+		 * can be used as a test for !Bsy.
+		 */
+		as = inb(ctlport+As);
+		if(as & reset){
+			/* nothing to do */
+		}
+		else if(dev){
+			outb(cmdport+Dh, dev);
+			dev = 0;
+		}
+		else if(ready == 0 || (as & ready)){
+			atadebug(0, 0, "ataready: %d 0x%2.2uX\n", micro, as);
+			return as;
+		}
+
+		if(micro-- <= 0){
+			atadebug(0, 0, "ataready: %d 0x%2.2uX\n", micro, as);
+			break;
+		}
+		microdelay(1);
+	}
+	atadebug(cmdport, ctlport, "ataready: timeout");
+
+	return -1;
+}
+
+/*
+static int
+atacsf(Drive* drive, vlong csf, int supported)
+{
+	ushort *info;
+	int cmdset, i, x;
+
+	if(supported)
+		info = &drive->info[Icsfs];
+	else
+		info = &drive->info[Icsfe];
+
+	for(i = 0; i < 3; i++){
+		x = (csf>>(16*i)) & 0xFFFF;
+		if(x == 0)
+			continue;
+		cmdset = info[i];
+		if(cmdset == 0 || cmdset == 0xFFFF)
+			return 0;
+		return cmdset & x;
+	}
+
+	return 0;
+}
+*/
+
+static int
+atadone(void* arg)
+{
+	return ((Ctlr*)arg)->done;
+}
+
+static int
+atarwmmode(Drive* drive, int cmdport, int ctlport, int dev)
+{
+	int as, maxrwm, rwm;
+
+	maxrwm = (drive->info[Imaxrwm] & 0xFF);
+	if(maxrwm == 0)
+		return 0;
+
+	/*
+	 * Sometimes drives come up with the current count set
+	 * to 0; if so, set a suitable value, otherwise believe
+	 * the value in Irwm if the 0x100 bit is set.
+	 */
+	if(drive->info[Irwm] & 0x100)
+		rwm = (drive->info[Irwm] & 0xFF);
+	else
+		rwm = 0;
+	if(rwm == 0)
+		rwm = maxrwm;
+	if(rwm > 16)
+		rwm = 16;
+	if(ataready(cmdport, ctlport, dev, Bsy|Drq, Drdy, 102*1000) < 0)
+		return 0;
+	outb(cmdport+Count, rwm);
+	outb(cmdport+Command, Csm);
+	microdelay(1);
+	as = ataready(cmdport, ctlport, 0, Bsy, Drdy|Df|Err, 1000);
+	inb(cmdport+Status);
+	if(as < 0 || (as & (Df|Err)))
+		return 0;
+
+	drive->rwm = rwm;
+
+	return rwm;
+}
+
+static int
+atadmamode(Drive* drive)
+{
+	int dma;
+
+	/*
+	 * Check if any DMA mode enabled.
+	 * Assumes the BIOS has picked and enabled the best.
+	 * This is completely passive at the moment, no attempt is
+	 * made to ensure the hardware is correctly set up.
+	 */
+	dma = drive->info[Imwdma] & 0x0707;
+	drive->dma = (dma>>8) & dma;
+	if(drive->dma == 0 && (drive->info[Ivalid] & 0x04)){
+		dma = drive->info[Iudma] & 0x7F7F;
+		drive->dma = (dma>>8) & dma;
+		if(drive->dma)
+			drive->dma |= 'U'<<16;
+	}
+
+	return dma;
+}
+
+static int
+ataidentify(int cmdport, int ctlport, int dev, int pkt, void* info)
+{
+	int as, command, drdy;
+
+	if(pkt){
+		command = Cidpkt;
+		drdy = 0;
+	}
+	else{
+		command = Cid;
+		drdy = Drdy;
+	}
+	as = ataready(cmdport, ctlport, dev, Bsy|Drq, drdy, 103*1000);
+	if(as < 0)
+		return as;
+	outb(cmdport+Command, command);
+	microdelay(1);
+
+	as = ataready(cmdport, ctlport, 0, Bsy, Drq|Err, 400*1000);
+	if(as < 0)
+		return -1;
+	if(as & Err)
+		return as;
+
+	memset(info, 0, 512);
+	inss(cmdport+Data, info, 256);
+	inb(cmdport+Status);
+
+	if(DEBUG & DbgIDENTIFY){
+		int i;
+		ushort *sp;
+
+		sp = (ushort*)info;
+		for(i = 0; i < 256; i++){
+			if(i && (i%16) == 0)
+				print("\n");
+			print(" %4.4uX", *sp);
+			sp++;
+		}
+		print("\n");
+	}
+
+	return 0;
+}
+
+static Drive*
+atadrive(int cmdport, int ctlport, int dev)
+{
+	Drive *drive;
+	int as, i, pkt;
+	uchar buf[512], *p;
+	ushort iconfig, *sp;
+
+	atadebug(0, 0, "identify: port 0x%uX dev 0x%2.2uX\n", cmdport, dev);
+	pkt = 1;
+retry:
+	as = ataidentify(cmdport, ctlport, dev, pkt, buf);
+	if(as < 0)
+		return nil;
+	if(as & Err){
+		if(pkt == 0)
+			return nil;
+		pkt = 0;
+		goto retry;
+	}
+
+	if((drive = malloc(sizeof(Drive))) == nil)
+		return nil;
+	drive->dev = dev;
+	memmove(drive->info, buf, sizeof(drive->info));
+	drive->sense[0] = 0x70;
+	drive->sense[7] = sizeof(drive->sense)-7;
+
+	drive->inquiry[2] = 2;
+	drive->inquiry[3] = 2;
+	drive->inquiry[4] = sizeof(drive->inquiry)-4;
+	p = &drive->inquiry[8];
+	sp = &drive->info[Imodel];
+	for(i = 0; i < 20; i++){
+		*p++ = *sp>>8;
+		*p++ = *sp++;
+	}
+
+	drive->secsize = 512;
+
+	/*
+	 * Beware the CompactFlash Association feature set.
+	 * Now, why this value in Iconfig just walks all over the bit
+	 * definitions used in the other parts of the ATA/ATAPI standards
+	 * is a mystery and a sign of true stupidity on someone's part.
+	 * Anyway, the standard says if this value is 0x848A then it's
+	 * CompactFlash and it's NOT a packet device.
+	 */
+	iconfig = drive->info[Iconfig];
+	if(iconfig != 0x848A && (iconfig & 0xC000) == 0x8000){
+		if(iconfig & 0x01)
+			drive->pkt = 16;
+		else
+			drive->pkt = 12;
+	}
+	else{
+		if(drive->info[Ivalid] & 0x0001){
+			drive->c = drive->info[Iccyl];
+			drive->h = drive->info[Ichead];
+			drive->s = drive->info[Icsec];
+		}
+		else{
+			drive->c = drive->info[Ilcyl];
+			drive->h = drive->info[Ilhead];
+			drive->s = drive->info[Ilsec];
+		}
+		if(drive->info[Icapabilities] & Mlba){
+			if(drive->info[Icsfs+1] & Maddr48){
+				drive->sectors = drive->info[Ilba48]
+					| (drive->info[Ilba48+1]<<16)
+					| ((vlong)drive->info[Ilba48+2]<<32);
+				drive->flags |= Lba48;
+			}
+			else{
+				drive->sectors = (drive->info[Ilba+1]<<16)
+					 |drive->info[Ilba];
+			}
+			drive->dev |= Lba;
+		}
+		else
+			drive->sectors = drive->c*drive->h*drive->s;
+		atarwmmode(drive, cmdport, ctlport, dev);
+	}
+	atadmamode(drive);	
+
+	if(DEBUG & DbgCONFIG){
+		print("dev %2.2uX port %uX config %4.4uX capabilities %4.4uX",
+			dev, cmdport, iconfig, drive->info[Icapabilities]);
+		print(" mwdma %4.4uX", drive->info[Imwdma]);
+		if(drive->info[Ivalid] & 0x04)
+			print(" udma %4.4uX", drive->info[Iudma]);
+		print(" dma %8.8uX rwm %ud", drive->dma, drive->rwm);
+		if(drive->flags&Lba48)
+			print("\tLLBA sectors %lld", drive->sectors);
+		print("\n");
+	}
+
+	return drive;
+}
+
+static void
+atasrst(int ctlport)
+{
+	/*
+	 * Srst is a big stick and may cause problems if further
+	 * commands are tried before the drives become ready again.
+	 * Also, there will be problems here if overlapped commands
+	 * are ever supported.
+	 */
+	microdelay(5);
+	outb(ctlport+Dc, Srst);
+	microdelay(5);
+	outb(ctlport+Dc, 0);
+	microdelay(2*1000);
+}
+
+static SDev*
+ataprobe(int cmdport, int ctlport, int irq)
+{
+	Ctlr* ctlr;
+	SDev *sdev;
+	Drive *drive;
+	int dev, error, rhi, rlo;
+	static int nonlegacy = 'C';
+	
+	if(ioalloc(cmdport, 8, 0, "atacmd") < 0) {
+		print("ataprobe: Cannot allocate %X\n", cmdport);
+		return nil;
+	}
+	if(ioalloc(ctlport+As, 1, 0, "atactl") < 0){
+		print("ataprobe: Cannot allocate %X\n", ctlport + As);
+		iofree(cmdport);
+		return nil;
+	}
+
+	/*
+	 * Try to detect a floating bus.
+	 * Bsy should be cleared. If not, see if the cylinder registers
+	 * are read/write capable.
+	 * If the master fails, try the slave to catch slave-only
+	 * configurations.
+	 * There's no need to restore the tested registers as they will
+	 * be reset on any detected drives by the Cedd command.
+	 * All this indicates is that there is at least one drive on the
+	 * controller; when the non-existent drive is selected in a
+	 * single-drive configuration the registers of the existing drive
+	 * are often seen, only command execution fails.
+	 */
+	dev = Dev0;
+	if(inb(ctlport+As) & Bsy){
+		outb(cmdport+Dh, dev);
+		microdelay(1);
+trydev1:
+		atadebug(cmdport, ctlport, "ataprobe bsy");
+		outb(cmdport+Cyllo, 0xAA);
+		outb(cmdport+Cylhi, 0x55);
+		outb(cmdport+Sector, 0xFF);
+		rlo = inb(cmdport+Cyllo);
+		rhi = inb(cmdport+Cylhi);
+		if(rlo != 0xAA && (rlo == 0xFF || rhi != 0x55)){
+			if(dev == Dev1){
+release:
+				iofree(cmdport);
+				iofree(ctlport+As);
+				return nil;
+			}
+			dev = Dev1;
+			if(ataready(cmdport, ctlport, dev, Bsy, 0, 20*1000) < 0)
+				goto trydev1;
+		}
+	}
+
+	/*
+	 * Disable interrupts on any detected controllers.
+	 */
+	outb(ctlport+Dc, Nien);
+tryedd1:
+	if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 105*1000) < 0){
+		/*
+		 * There's something there, but it didn't come up clean,
+		 * so try hitting it with a big stick. The timing here is
+		 * wrong but this is a last-ditch effort and it sometimes
+		 * gets some marginal hardware back online.
+		 */
+		atasrst(ctlport);
+		if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 106*1000) < 0)
+			goto release;
+	}
+
+	/*
+	 * Can only get here if controller is not busy.
+	 * If there are drives Bsy will be set within 400nS,
+	 * must wait 2mS before testing Status.
+	 * Wait for the command to complete (6 seconds max).
+	 */
+	outb(cmdport+Command, Cedd);
+	delay(2);
+	if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 6*1000*1000) < 0)
+		goto release;
+
+	/*
+	 * If bit 0 of the error register is set then the selected drive
+	 * exists. This is enough to detect single-drive configurations.
+	 * However, if the master exists there is no way short of executing
+	 * a command to determine if a slave is present.
+	 * It appears possible to get here testing Dev0 although it doesn't
+	 * exist and the EDD won't take, so try again with Dev1.
+	 */
+	error = inb(cmdport+Error);
+	atadebug(cmdport, ctlport, "ataprobe: dev %uX", dev);
+	if((error & ~0x80) != 0x01){
+		if(dev == Dev1)
+			goto release;
+		dev = Dev1;
+		goto tryedd1;
+	}
+
+	/*
+	 * At least one drive is known to exist, try to
+	 * identify it. If that fails, don't bother checking
+	 * any further.
+	 * If the one drive found is Dev0 and the EDD command
+	 * didn't indicate Dev1 doesn't exist, check for it.
+	 */
+	if((drive = atadrive(cmdport, ctlport, dev)) == nil)
+		goto release;
+	if((ctlr = malloc(sizeof(Ctlr))) == nil){
+		free(drive);
+		goto release;
+	}
+	memset(ctlr, 0, sizeof(Ctlr));
+	if((sdev = malloc(sizeof(SDev))) == nil){
+		free(ctlr);
+		free(drive);
+		goto release;
+	}
+	memset(sdev, 0, sizeof(SDev));
+	drive->ctlr = ctlr;
+	if(dev == Dev0){
+		ctlr->drive[0] = drive;
+		if(!(error & 0x80)){
+			/*
+			 * Always leave Dh pointing to a valid drive,
+			 * otherwise a subsequent call to ataready on
+			 * this controller may try to test a bogus Status.
+			 * Ataprobe is the only place possibly invalid
+			 * drives should be selected.
+			 */
+			drive = atadrive(cmdport, ctlport, Dev1);
+			if(drive != nil){
+				drive->ctlr = ctlr;
+				ctlr->drive[1] = drive;
+			}
+			else{
+				outb(cmdport+Dh, Dev0);
+				microdelay(1);
+			}
+		}
+	}
+	else
+		ctlr->drive[1] = drive;
+
+	ctlr->cmdport = cmdport;
+	ctlr->ctlport = ctlport;
+	ctlr->irq = irq;
+	ctlr->tbdf = BUSUNKNOWN;
+	ctlr->command = Cedd;		/* debugging */
+	
+	switch(cmdport){
+	default:
+		sdev->idno = nonlegacy;
+		break;
+	case 0x1F0:
+		sdev->idno = 'C';
+		nonlegacy = 'E';
+		break;
+	case 0x170:
+		sdev->idno = 'D';
+		nonlegacy = 'E';
+		break;
+	}
+	sdev->ifc = &sdataifc;
+	sdev->ctlr = ctlr;
+	sdev->nunit = 2;
+	ctlr->sdev = sdev;
+
+	return sdev;
+}
+
+static void
+ataclear(SDev *sdev)
+{
+	Ctlr* ctlr;
+
+	ctlr = sdev->ctlr;
+	iofree(ctlr->cmdport);
+	iofree(ctlr->ctlport + As);
+
+	if (ctlr->drive[0])
+		free(ctlr->drive[0]);
+	if (ctlr->drive[1])
+		free(ctlr->drive[1]);
+	if (sdev->name)
+		free(sdev->name);
+	if (sdev->unitflg)
+		free(sdev->unitflg);
+	if (sdev->unit)
+		free(sdev->unit);
+	free(ctlr);
+	free(sdev);
+}
+
+static char *
+atastat(SDev *sdev, char *p, char *e)
+{
+	Ctlr *ctlr = sdev->ctlr;
+
+	return seprint(p, e, "%s ata port %X ctl %X irq %d\n", 
+		    	       sdev->name, ctlr->cmdport, ctlr->ctlport, ctlr->irq);
+}
+
+static SDev*
+ataprobew(DevConf *cf)
+{
+	char *p;
+	ISAConf isa;
+	
+	if (cf->nports != 2)
+		error(Ebadarg);
+
+	memset(&isa, 0, sizeof isa);
+	isa.port = cf->ports[0].port;
+	isa.irq = cf->intnum;
+	if((p=strchr(cf->type, '/')) == nil || pcmspecial(p+1, &isa) < 0)
+		error("cannot find controller");
+
+	return ataprobe(cf->ports[0].port, cf->ports[1].port, cf->intnum);
+}
+
+/*
+ * These are duplicated with sdsetsense, etc., in devsd.c, but
+ * those assume that the disk is not SCSI while in fact here
+ * ata drives are not SCSI but ATAPI ones kind of are.
+ */
+static int
+atasetsense(Drive* drive, int status, int key, int asc, int ascq)
+{
+	drive->sense[2] = key;
+	drive->sense[12] = asc;
+	drive->sense[13] = ascq;
+
+	return status;
+}
+
+static int
+atamodesense(Drive* drive, uchar* cmd)
+{
+	int len;
+
+	/*
+	 * Fake a vendor-specific request with page code 0,
+	 * return the drive info.
+	 */
+	if((cmd[2] & 0x3F) != 0 && (cmd[2] & 0x3F) != 0x3F)
+		return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
+	len = (cmd[7]<<8)|cmd[8];
+	if(len == 0)
+		return SDok;
+	if(len < 8+sizeof(drive->info))
+		return atasetsense(drive, SDcheck, 0x05, 0x1A, 0);
+	if(drive->data == nil || drive->dlen < len)
+		return atasetsense(drive, SDcheck, 0x05, 0x20, 1);
+	memset(drive->data, 0, 8);
+	drive->data[0] = sizeof(drive->info)>>8;
+	drive->data[1] = sizeof(drive->info);
+	memmove(drive->data+8, drive->info, sizeof(drive->info));
+	drive->data += 8+sizeof(drive->info);
+
+	return SDok;
+}
+
+static int
+atastandby(Drive* drive, int period)
+{
+	Ctlr* ctlr;
+	int cmdport, done;
+
+	ctlr = drive->ctlr;
+	drive->command = Cstandby;
+	qlock(ctlr);
+
+	cmdport = ctlr->cmdport;
+	ilock(ctlr);
+	outb(cmdport+Count, period);
+	outb(cmdport+Dh, drive->dev);
+	ctlr->done = 0;
+	ctlr->curdrive = drive;
+	ctlr->command = Cstandby;	/* debugging */
+	outb(cmdport+Command, Cstandby);
+	iunlock(ctlr);
+
+	while(waserror())
+		;
+	tsleep(ctlr, atadone, ctlr, 60*1000);
+	poperror();
+
+	done = ctlr->done;
+	qunlock(ctlr);
+
+	if(!done || (drive->status & Err))
+		return atasetsense(drive, SDcheck, 4, 8, drive->error);
+	return SDok;
+}
+
+static void
+atanop(Drive* drive, int subcommand)
+{
+	Ctlr* ctlr;
+	int as, cmdport, ctlport, timeo;
+
+	/*
+	 * Attempt to abort a command by using NOP.
+	 * In response, the drive is supposed to set Abrt
+	 * in the Error register, set (Drdy|Err) in Status
+	 * and clear Bsy when done. However, some drives
+	 * (e.g. ATAPI Zip) just go Bsy then clear Status
+	 * when done, hence the timeout loop only on Bsy
+	 * and the forced setting of drive->error.
+	 */
+	ctlr = drive->ctlr;
+	cmdport = ctlr->cmdport;
+	outb(cmdport+Features, subcommand);
+	outb(cmdport+Dh, drive->dev);
+	ctlr->command = Cnop;		/* debugging */
+	outb(cmdport+Command, Cnop);
+
+	microdelay(1);
+	ctlport = ctlr->ctlport;
+	for(timeo = 0; timeo < 1000; timeo++){
+		as = inb(ctlport+As);
+		if(!(as & Bsy))
+			break;
+		microdelay(1);
+	}
+	drive->error |= Abrt;
+}
+
+static void
+ataabort(Drive* drive, int dolock)
+{
+	/*
+	 * If NOP is available (packet commands) use it otherwise
+	 * must try a software reset.
+	 */
+	if(dolock)
+		ilock(drive->ctlr);
+	if(drive->info[Icsfs] & Mnop)
+		atanop(drive, 0);
+	else{
+		atasrst(drive->ctlr->ctlport);
+		drive->error |= Abrt;
+	}
+	if(dolock)
+		iunlock(drive->ctlr);
+}
+
+static int
+atadmasetup(Drive* drive, int len)
+{
+	Prd *prd;
+	ulong pa;
+	Ctlr *ctlr;
+	int bmiba, bmisx, count, i, span;
+
+	ctlr = drive->ctlr;
+	pa = PCIWADDR(drive->data);
+	if(pa & 0x03)
+		return -1;
+
+	/*
+	 * Sometimes drives identify themselves as being DMA capable
+	 * although they are not on a busmastering controller.
+	 */
+	prd = ctlr->prdt;
+	if(prd == nil){
+		drive->dmactl = 0;
+		print("disabling dma: not on a busmastering controller\n");
+		return -1;
+	}
+
+	for(i = 0; len && i < Nprd; i++){
+		prd->pa = pa;
+		span = ROUNDUP(pa, ctlr->span);
+		if(span == pa)
+			span += ctlr->span;
+		count = span - pa;
+		if(count >= len){
+			prd->count = PrdEOT|len;
+			break;
+		}
+		prd->count = count;
+		len -= count;
+		pa += count;
+		prd++;
+	}
+	if(i == Nprd)
+		(prd-1)->count |= PrdEOT;
+
+	bmiba = ctlr->bmiba;
+	outl(bmiba+Bmidtpx, PCIWADDR(ctlr->prdt));
+	if(drive->write)
+		outb(ctlr->bmiba+Bmicx, 0);
+	else
+		outb(ctlr->bmiba+Bmicx, Rwcon);
+	bmisx = inb(bmiba+Bmisx);
+	outb(bmiba+Bmisx, bmisx|Ideints|Idedmae);
+
+	return 0;
+}
+
+static void
+atadmastart(Ctlr* ctlr, int write)
+{
+	if(write)
+		outb(ctlr->bmiba+Bmicx, Ssbm);
+	else
+		outb(ctlr->bmiba+Bmicx, Rwcon|Ssbm);
+}
+
+static int
+atadmastop(Ctlr* ctlr)
+{
+	int bmiba;
+
+	bmiba = ctlr->bmiba;
+	outb(bmiba+Bmicx, inb(bmiba+Bmicx) & ~Ssbm);
+
+	return inb(bmiba+Bmisx);
+}
+
+static void
+atadmainterrupt(Drive* drive, int count)
+{
+	Ctlr* ctlr;
+	int bmiba, bmisx;
+
+	ctlr = drive->ctlr;
+	bmiba = ctlr->bmiba;
+	bmisx = inb(bmiba+Bmisx);
+	switch(bmisx & (Ideints|Idedmae|Bmidea)){
+	case Bmidea:
+		/*
+		 * Data transfer still in progress, nothing to do
+		 * (this should never happen).
+		 */
+		return;
+
+	case Ideints:
+	case Ideints|Bmidea:
+		/*
+		 * Normal termination, tidy up.
+		 */
+		drive->data += count;
+		break;
+
+	default:
+		/*
+		 * What's left are error conditions (memory transfer
+		 * problem) and the device is not done but the PRD is
+		 * exhausted. For both cases must somehow tell the
+		 * drive to abort.
+		 */
+		ataabort(drive, 0);
+		break;
+	}
+	atadmastop(ctlr);
+	ctlr->done = 1;
+}
+
+static void
+atapktinterrupt(Drive* drive)
+{
+	Ctlr* ctlr;
+	int cmdport, len;
+
+	ctlr = drive->ctlr;
+	cmdport = ctlr->cmdport;
+	switch(inb(cmdport+Ir) & (/*Rel|*/Io|Cd)){
+	case Cd:
+		outss(cmdport+Data, drive->pktcmd, drive->pkt/2);
+		break;
+
+	case 0:
+		len = (inb(cmdport+Bytehi)<<8)|inb(cmdport+Bytelo);
+		if(drive->data+len > drive->limit){
+			atanop(drive, 0);
+			break;
+		}
+		outss(cmdport+Data, drive->data, len/2);
+		drive->data += len;
+		break;
+
+	case Io:
+		len = (inb(cmdport+Bytehi)<<8)|inb(cmdport+Bytelo);
+		if(drive->data+len > drive->limit){
+			atanop(drive, 0);
+			break;
+		}
+		inss(cmdport+Data, drive->data, len/2);
+		drive->data += len;
+		break;
+
+	case Io|Cd:
+		if(drive->pktdma)
+			atadmainterrupt(drive, drive->dlen);
+		else
+			ctlr->done = 1;
+		break;
+	}
+}
+
+static int
+atapktio(Drive* drive, uchar* cmd, int clen)
+{
+	Ctlr *ctlr;
+	int as, cmdport, ctlport, len, r, timeo;
+
+	if(cmd[0] == 0x5A && (cmd[2] & 0x3F) == 0)
+		return atamodesense(drive, cmd);
+
+	r = SDok;
+
+	drive->command = Cpkt;
+	memmove(drive->pktcmd, cmd, clen);
+	memset(drive->pktcmd+clen, 0, drive->pkt-clen);
+	drive->limit = drive->data+drive->dlen;
+
+	ctlr = drive->ctlr;
+	cmdport = ctlr->cmdport;
+	ctlport = ctlr->ctlport;
+
+	qlock(ctlr);
+
+	as = ataready(cmdport, ctlport, drive->dev, Bsy|Drq, Drdy, 107*1000);
+	/* used to test as&Chk as failure too, but some CD readers use that for media change */
+	if(as < 0){
+		qunlock(ctlr);
+		return -1;
+	}
+
+	ilock(ctlr);
+	if(drive->dlen && drive->dmactl && !atadmasetup(drive, drive->dlen))
+		drive->pktdma = Dma;
+	else
+		drive->pktdma = 0;
+
+	outb(cmdport+Features, drive->pktdma);
+	outb(cmdport+Count, 0);
+	outb(cmdport+Sector, 0);
+	len = 16*drive->secsize;
+	outb(cmdport+Bytelo, len);
+	outb(cmdport+Bytehi, len>>8);
+	outb(cmdport+Dh, drive->dev);
+	ctlr->done = 0;
+	ctlr->curdrive = drive;
+	ctlr->command = Cpkt;		/* debugging */
+	if(drive->pktdma)
+		atadmastart(ctlr, drive->write);
+	outb(cmdport+Command, Cpkt);
+
+	if((drive->info[Iconfig] & Mdrq) != 0x0020){
+		microdelay(1);
+		as = ataready(cmdport, ctlport, 0, Bsy, Drq|Chk, 4*1000);
+		if(as < 0 || (as & (Bsy|Chk))){
+			drive->status = as<0 ? 0 : as;
+			ctlr->curdrive = nil;
+			ctlr->done = 1;
+			r = SDtimeout;
+		}else
+			atapktinterrupt(drive);
+	}
+	iunlock(ctlr);
+
+	while(waserror())
+		;
+	if(!drive->pktdma)
+		sleep(ctlr, atadone, ctlr);
+	else for(timeo = 0; !ctlr->done; timeo++){
+		tsleep(ctlr, atadone, ctlr, 1000);
+		if(ctlr->done)
+			break;
+		ilock(ctlr);
+		atadmainterrupt(drive, 0);
+		if(!drive->error && timeo > 20){
+			ataabort(drive, 0);
+			atadmastop(ctlr);
+			drive->dmactl = 0;
+			drive->error |= Abrt;
+		}
+		if(drive->error){
+			drive->status |= Chk;
+			ctlr->curdrive = nil;
+		}
+		iunlock(ctlr);
+	}
+	poperror();
+
+	qunlock(ctlr);
+
+	if(drive->status & Chk)
+		r = SDcheck;
+
+	return r;
+}
+
+static uchar cmd48[256] = {
+	[Crs]	Crs48,
+	[Crd]	Crd48,
+	[Crdq]	Crdq48,
+	[Crsm]	Crsm48,
+	[Cws]	Cws48,
+	[Cwd]	Cwd48,
+	[Cwdq]	Cwdq48,
+	[Cwsm]	Cwsm48,
+};
+
+static int
+atageniostart(Drive* drive, uvlong lba)
+{
+	Ctlr *ctlr;
+	uchar cmd;
+	int as, c, cmdport, ctlport, h, len, s, use48;
+
+	use48 = 0;
+	if((drive->flags&Lba48always) || lba > Last28 || drive->count > 256){
+		if(!(drive->flags & Lba48))
+			return -1;
+		use48 = 1;
+		c = h = s = 0;
+	}
+	else if(drive->dev & Lba){
+		c = (lba>>8) & 0xFFFF;
+		h = (lba>>24) & 0x0F;
+		s = lba & 0xFF;
+	}
+	else{
+		c = lba/(drive->s*drive->h);
+		h = ((lba/drive->s) % drive->h);
+		s = (lba % drive->s) + 1;
+	}
+
+	ctlr = drive->ctlr;
+	cmdport = ctlr->cmdport;
+	ctlport = ctlr->ctlport;
+	if(ataready(cmdport, ctlport, drive->dev, Bsy|Drq, Drdy, 101*1000) < 0)
+		return -1;
+
+	ilock(ctlr);
+	if(drive->dmactl && !atadmasetup(drive, drive->count*drive->secsize)){
+		if(drive->write)
+			drive->command = Cwd;
+		else
+			drive->command = Crd;
+	}
+	else if(drive->rwmctl){
+		drive->block = drive->rwm*drive->secsize;
+		if(drive->write)
+			drive->command = Cwsm;
+		else
+			drive->command = Crsm;
+	}
+	else{
+		drive->block = drive->secsize;
+		if(drive->write)
+			drive->command = Cws;
+		else
+			drive->command = Crs;
+	}
+	drive->limit = drive->data + drive->count*drive->secsize;
+	cmd = drive->command;
+	if(use48){
+		outb(cmdport+Count, drive->count>>8);
+		outb(cmdport+Count, drive->count);
+		outb(cmdport+Lbalo, lba>>24);
+		outb(cmdport+Lbalo, lba);
+		outb(cmdport+Lbamid, lba>>32);
+		outb(cmdport+Lbamid, lba>>8);
+		outb(cmdport+Lbahi, lba>>40);
+		outb(cmdport+Lbahi, lba>>16);
+		outb(cmdport+Dh, drive->dev|Lba);
+		cmd = cmd48[cmd];
+
+		if(DEBUG & Dbg48BIT)
+			print("using 48-bit commands\n");
+	}
+	else{
+		outb(cmdport+Count, drive->count);
+		outb(cmdport+Sector, s);
+		outb(cmdport+Cyllo, c);
+		outb(cmdport+Cylhi, c>>8);
+		outb(cmdport+Dh, drive->dev|h);
+	}
+	ctlr->done = 0;
+	ctlr->curdrive = drive;
+	ctlr->command = drive->command;	/* debugging */
+	outb(cmdport+Command, cmd);
+
+	switch(drive->command){
+	case Cws:
+	case Cwsm:
+		microdelay(1);
+		/* 10*1000 for flash ide drives - maybe detect them? */
+		as = ataready(cmdport, ctlport, 0, Bsy, Drq|Err, 10*1000);
+		if(as < 0 || (as & Err)){
+			iunlock(ctlr);
+			return -1;
+		}
+		len = drive->block;
+		if(drive->data+len > drive->limit)
+			len = drive->limit-drive->data;
+		outss(cmdport+Data, drive->data, len/2);
+		break;
+
+	case Crd:
+	case Cwd:
+		atadmastart(ctlr, drive->write);
+		break;
+	}
+	iunlock(ctlr);
+
+	return 0;
+}
+
+static int
+atagenioretry(Drive* drive)
+{
+	if(drive->dmactl){
+		drive->dmactl = 0;
+		print("atagenioretry: disabling dma\n");
+	}
+	else if(drive->rwmctl)
+		drive->rwmctl = 0;
+	else
+		return atasetsense(drive, SDcheck, 4, 8, drive->error);
+
+	return SDretry;
+}
+
+static int
+atagenio(Drive* drive, uchar* cmd, int clen)
+{
+	uchar *p;
+	Ctlr *ctlr;
+	vlong lba, len;
+	int count, maxio;
+
+	/*
+	 * Map SCSI commands into ATA commands for discs.
+	 * Fail any command with a LUN except INQUIRY which
+	 * will return 'logical unit not supported'.
+	 */
+	if((cmd[1]>>5) && cmd[0] != 0x12)
+		return atasetsense(drive, SDcheck, 0x05, 0x25, 0);
+
+	switch(cmd[0]){
+	default:
+		return atasetsense(drive, SDcheck, 0x05, 0x20, 0);
+
+	case 0x00:			/* test unit ready */
+		return SDok;
+
+	case 0x03:			/* request sense */
+		if(cmd[4] < sizeof(drive->sense))
+			len = cmd[4];
+		else
+			len = sizeof(drive->sense);
+		if(drive->data && drive->dlen >= len){
+			memmove(drive->data, drive->sense, len);
+			drive->data += len;
+		}
+		return SDok;
+
+	case 0x12:			/* inquiry */
+		if(cmd[4] < sizeof(drive->inquiry))
+			len = cmd[4];
+		else
+			len = sizeof(drive->inquiry);
+		if(drive->data && drive->dlen >= len){
+			memmove(drive->data, drive->inquiry, len);
+			drive->data += len;
+		}
+		return SDok;
+
+	case 0x1B:			/* start/stop unit */
+		/*
+		 * NOP for now, can use the power management feature
+		 * set later.
+		 */
+		return SDok;
+
+	case 0x25:			/* read capacity */
+		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
+			return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
+		if(drive->data == nil || drive->dlen < 8)
+			return atasetsense(drive, SDcheck, 0x05, 0x20, 1);
+		/*
+		 * Read capacity returns the LBA of the last sector.
+		 */
+		len = drive->sectors-1;
+		p = drive->data;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p++ = len;
+		len = drive->secsize;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p = len;
+		drive->data += 8;
+		return SDok;
+
+	case 0x9E:			/* long read capacity */
+		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
+			return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
+		if(drive->data == nil || drive->dlen < 8)
+			return atasetsense(drive, SDcheck, 0x05, 0x20, 1);
+		/*
+		 * Read capacity returns the LBA of the last sector.
+		 */
+		len = drive->sectors-1;
+		p = drive->data;
+		*p++ = len>>56;
+		*p++ = len>>48;
+		*p++ = len>>40;
+		*p++ = len>>32;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p++ = len;
+		len = drive->secsize;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p = len;
+		drive->data += 12;
+		return SDok;
+
+	case 0x28:			/* read */
+	case 0x88:
+	case 0x2a:			/* write */
+	case 0x8a:
+		break;
+
+	case 0x5A:
+		return atamodesense(drive, cmd);
+	}
+
+	ctlr = drive->ctlr;
+	if(clen == 16){
+		/* ata commands only go to 48-bit lba */
+		if(cmd[2] || cmd[3])
+			return atasetsense(drive, SDcheck, 3, 0xc, 2);
+		lba = (uvlong)cmd[4]<<40 | (uvlong)cmd[5]<<32;
+		lba |= cmd[6]<<24 | cmd[7]<<16 | cmd[8]<<8 | cmd[9];
+		count = cmd[10]<<24 | cmd[11]<<16 | cmd[12]<<8 | cmd[13];
+	}else{
+		lba = cmd[2]<<24 | cmd[3]<<16 | cmd[4]<<8 | cmd[5];
+		count = cmd[7]<<8 | cmd[8];
+	}
+	if(drive->data == nil)
+		return SDok;
+	if(drive->dlen < count*drive->secsize)
+		count = drive->dlen/drive->secsize;
+	qlock(ctlr);
+	if(ctlr->maxio)
+		maxio = ctlr->maxio;
+	else if(drive->flags & Lba48)
+		maxio = 65536;
+	else
+		maxio = 256;
+	while(count){
+		if(count > maxio)
+			drive->count = maxio;
+		else
+			drive->count = count;
+		if(atageniostart(drive, lba)){
+			ilock(ctlr);
+			atanop(drive, 0);
+			iunlock(ctlr);
+			qunlock(ctlr);
+			return atagenioretry(drive);
+		}
+
+		while(waserror())
+			;
+		tsleep(ctlr, atadone, ctlr, 60*1000);
+		poperror();
+		if(!ctlr->done){
+			/*
+			 * What should the above timeout be? In
+			 * standby and sleep modes it could take as
+			 * long as 30 seconds for a drive to respond.
+			 * Very hard to get out of this cleanly.
+			 */
+			atadumpstate(drive, cmd, lba, count);
+			ataabort(drive, 1);
+			qunlock(ctlr);
+			return atagenioretry(drive);
+		}
+
+		if(drive->status & Err){
+			qunlock(ctlr);
+			return atasetsense(drive, SDcheck, 4, 8, drive->error);
+		}
+		count -= drive->count;
+		lba += drive->count;
+	}
+	qunlock(ctlr);
+
+	return SDok;
+}
+
+static int
+atario(SDreq* r)
+{
+	Ctlr *ctlr;
+	Drive *drive;
+	SDunit *unit;
+	uchar cmd10[10], *cmdp, *p;
+	int clen, reqstatus, status;
+
+	unit = r->unit;
+	if((ctlr = unit->dev->ctlr) == nil || ctlr->drive[unit->subno] == nil){
+		r->status = SDtimeout;
+		return SDtimeout;
+	}
+	drive = ctlr->drive[unit->subno];
+
+	/*
+	 * Most SCSI commands can be passed unchanged except for
+	 * the padding on the end. The few which require munging
+	 * are not used internally. Mode select/sense(6) could be
+	 * converted to the 10-byte form but it's not worth the
+	 * effort. Read/write(6) are easy.
+	 */
+	switch(r->cmd[0]){
+	case 0x08:			/* read */
+	case 0x0A:			/* write */
+		cmdp = cmd10;
+		memset(cmdp, 0, sizeof(cmd10));
+		cmdp[0] = r->cmd[0]|0x20;
+		cmdp[1] = r->cmd[1] & 0xE0;
+		cmdp[5] = r->cmd[3];
+		cmdp[4] = r->cmd[2];
+		cmdp[3] = r->cmd[1] & 0x0F;
+		cmdp[8] = r->cmd[4];
+		clen = sizeof(cmd10);
+		break;
+
+	default:
+		cmdp = r->cmd;
+		clen = r->clen;
+		break;
+	}
+
+	qlock(drive);
+retry:
+	drive->write = r->write;
+	drive->data = r->data;
+	drive->dlen = r->dlen;
+
+	drive->status = 0;
+	drive->error = 0;
+	if(drive->pkt)
+		status = atapktio(drive, cmdp, clen);
+	else
+		status = atagenio(drive, cmdp, clen);
+	if(status == SDretry){
+		if(DbgDEBUG)
+			print("%s: retry: dma %8.8uX rwm %4.4uX\n",
+				unit->name, drive->dmactl, drive->rwmctl);
+		goto retry;
+	}
+	if(status == SDok){
+		atasetsense(drive, SDok, 0, 0, 0);
+		if(drive->data){
+			p = r->data;
+			r->rlen = drive->data - p;
+		}
+		else
+			r->rlen = 0;
+	}
+	else if(status == SDcheck && !(r->flags & SDnosense)){
+		drive->write = 0;
+		memset(cmd10, 0, sizeof(cmd10));
+		cmd10[0] = 0x03;
+		cmd10[1] = r->lun<<5;
+		cmd10[4] = sizeof(r->sense)-1;
+		drive->data = r->sense;
+		drive->dlen = sizeof(r->sense)-1;
+		drive->status = 0;
+		drive->error = 0;
+		if(drive->pkt)
+			reqstatus = atapktio(drive, cmd10, 6);
+		else
+			reqstatus = atagenio(drive, cmd10, 6);
+		if(reqstatus == SDok){
+			r->flags |= SDvalidsense;
+			atasetsense(drive, SDok, 0, 0, 0);
+		}
+	}
+	qunlock(drive);
+	r->status = status;
+	if(status != SDok)
+		return status;
+
+	/*
+	 * Fix up any results.
+	 * Many ATAPI CD-ROMs ignore the LUN field completely and
+	 * return valid INQUIRY data. Patch the response to indicate
+	 * 'logical unit not supported' if the LUN is non-zero.
+	 */
+	switch(cmdp[0]){
+	case 0x12:			/* inquiry */
+		if((p = r->data) == nil)
+			break;
+		if((cmdp[1]>>5) && (!drive->pkt || (p[0] & 0x1F) == 0x05))
+			p[0] = 0x7F;
+		/*FALLTHROUGH*/
+	default:
+		break;
+	}
+
+	return SDok;
+}
+
+static void
+atainterrupt(Ureg*, void* arg)
+{
+	Ctlr *ctlr;
+	Drive *drive;
+	int cmdport, len, status;
+
+	ctlr = arg;
+
+	ilock(ctlr);
+	if(inb(ctlr->ctlport+As) & Bsy){
+		iunlock(ctlr);
+		if(DEBUG & DbgBsy)
+			print("IBsy+");
+		return;
+	}
+	cmdport = ctlr->cmdport;
+	status = inb(cmdport+Status);
+	if((drive = ctlr->curdrive) == nil){
+		iunlock(ctlr);
+		if((DEBUG & DbgINL) && ctlr->command != Cedd)
+			print("Inil%2.2uX+", ctlr->command);
+		return;
+	}
+
+	if(status & Err)
+		drive->error = inb(cmdport+Error);
+	else switch(drive->command){
+	default:
+		drive->error = Abrt;
+		break;
+
+	case Crs:
+	case Crsm:
+		if(!(status & Drq)){
+			drive->error = Abrt;
+			break;
+		}
+		len = drive->block;
+		if(drive->data+len > drive->limit)
+			len = drive->limit-drive->data;
+		inss(cmdport+Data, drive->data, len/2);
+		drive->data += len;
+		if(drive->data >= drive->limit)
+			ctlr->done = 1;
+		break;
+
+	case Cws:
+	case Cwsm:
+		len = drive->block;
+		if(drive->data+len > drive->limit)
+			len = drive->limit-drive->data;
+		drive->data += len;
+		if(drive->data >= drive->limit){
+			ctlr->done = 1;
+			break;
+		}
+		if(!(status & Drq)){
+			drive->error = Abrt;
+			break;
+		}
+		len = drive->block;
+		if(drive->data+len > drive->limit)
+			len = drive->limit-drive->data;
+		outss(cmdport+Data, drive->data, len/2);
+		break;
+
+	case Cpkt:
+		atapktinterrupt(drive);
+		break;
+
+	case Crd:
+	case Cwd:
+		atadmainterrupt(drive, drive->count*drive->secsize);
+		break;
+
+	case Cstandby:
+		ctlr->done = 1;
+		break;
+	}
+	iunlock(ctlr);
+
+	if(drive->error){
+		status |= Err;
+		ctlr->done = 1;
+	}
+
+	if(ctlr->done){
+		ctlr->curdrive = nil;
+		drive->status = status;
+		wakeup(ctlr);
+	}
+}
+
+static SDev*
+atapnp(void)
+{
+	Ctlr *ctlr;
+	Pcidev *p;
+	SDev *legacy[2], *sdev, *head, *tail;
+	int channel, ispc87415, maxio, pi, r, span;
+
+	legacy[0] = legacy[1] = head = tail = nil;
+	if(sdev = ataprobe(0x1F0, 0x3F4, IrqATA0)){
+		head = tail = sdev;
+		legacy[0] = sdev;
+	}
+	if(sdev = ataprobe(0x170, 0x374, IrqATA1)){
+		if(head != nil)
+			tail->next = sdev;
+		else
+			head = sdev;
+		tail = sdev;
+		legacy[1] = sdev;
+	}
+
+	p = nil;
+	while(p = pcimatch(p, 0, 0)){
+		/*
+		 * Look for devices with the correct class and sub-class
+		 * code and known device and vendor ID; add native-mode
+		 * channels to the list to be probed, save info for the
+		 * compatibility mode channels.
+		 * Note that the legacy devices should not be considered
+		 * PCI devices by the interrupt controller.
+		 * For both native and legacy, save info for busmastering
+		 * if capable.
+		 * Promise Ultra ATA/66 (PDC20262) appears to
+		 * 1) give a sub-class of 'other mass storage controller'
+		 *    instead of 'IDE controller', regardless of whether it's
+		 *    the only controller or not;
+		 * 2) put 0 in the programming interface byte (probably
+		 *    as a consequence of 1) above).
+		 * Sub-class code 0x04 is 'RAID controller', e.g. VIA VT8237.
+		 */
+		if(p->ccrb != 0x01)
+			continue;
+		if(p->ccru != 0x01 && p->ccru != 0x04 && p->ccru != 0x80)
+			continue;
+		pi = p->ccrp;
+		ispc87415 = 0;
+		maxio = 0;
+		span = BMspan;
+
+		switch((p->did<<16)|p->vid){
+		default:
+			continue;
+
+		case (0x0002<<16)|0x100B:	/* NS PC87415 */
+			/*
+			 * Disable interrupts on both channels until
+			 * after they are probed for drives.
+			 * This must be called before interrupts are
+			 * enabled because the IRQ may be shared.
+			 */
+			ispc87415 = 1;
+			pcicfgw32(p, 0x40, 0x00000300);
+			break;
+		case (0x1000<<16)|0x1042:	/* PC-Tech RZ1000 */
+			/*
+			 * Turn off prefetch. Overkill, but cheap.
+			 */
+			r = pcicfgr32(p, 0x40);
+			r &= ~0x2000;
+			pcicfgw32(p, 0x40, r);
+			break;
+		case (0x4D38<<16)|0x105A:	/* Promise PDC20262 */
+		case (0x4D30<<16)|0x105A:	/* Promise PDC202xx */
+		case (0x4D68<<16)|0x105A:	/* Promise PDC20268 */
+		case (0x4D69<<16)|0x105A:	/* Promise Ultra/133 TX2 */
+		case (0x3373<<16)|0x105A:	/* Promise 20378 RAID */
+		case (0x3149<<16)|0x1106:	/* VIA VT8237 SATA/RAID */
+		case (0x3112<<16)|0x1095:	/* SiI 3112 SATA/RAID */
+			maxio = 15;
+			span = 8*1024;
+			/*FALLTHROUGH*/
+		case (0x0680<<16)|0x1095:	/* SiI 0680/680A PATA133 ATAPI/RAID */
+		case (0x3114<<16)|0x1095:	/* SiI 3114 SATA/RAID */
+			pi = 0x85;
+			break;
+		case (0x0004<<16)|0x1103:	/* HighPoint HPT366 */
+			pi = 0x85;
+			/*
+			 * Turn off fast interrupt prediction.
+			 */
+			if((r = pcicfgr8(p, 0x51)) & 0x80)
+				pcicfgw8(p, 0x51, r & ~0x80);
+			if((r = pcicfgr8(p, 0x55)) & 0x80)
+				pcicfgw8(p, 0x55, r & ~0x80);
+			break;
+		case (0x0640<<16)|0x1095:	/* CMD 640B */
+			/*
+			 * Bugfix code here...
+			 */
+			break;
+		case (0x7441<<16)|0x1022:	/* AMD 768 */
+			/*
+			 * Set:
+			 *	0x41	prefetch, postwrite;
+			 *	0x43	FIFO configuration 1/2 and 1/2;
+			 *	0x44	status register read retry;
+			 *	0x46	DMA read and end of sector flush.
+			 */
+			r = pcicfgr8(p, 0x41);
+			pcicfgw8(p, 0x41, r|0xF0);
+			r = pcicfgr8(p, 0x43);
+			pcicfgw8(p, 0x43, (r & 0x90)|0x2A);
+			r = pcicfgr8(p, 0x44);
+			pcicfgw8(p, 0x44, r|0x08);
+			r = pcicfgr8(p, 0x46);
+			pcicfgw8(p, 0x46, (r & 0x0C)|0xF0);
+			/*FALLTHROUGH*/
+		case (0x7401<<16)|0x1022:	/* AMD 755 Cobra */
+		case (0x7409<<16)|0x1022:	/* AMD 756 Viper */
+		case (0x7410<<16)|0x1022:	/* AMD 766 Viper Plus */
+		case (0x7469<<16)|0x1022:	/* AMD 3111 */
+			/*
+			 * This can probably be lumped in with the 768 above.
+			 */
+			/*FALLTHROUGH*/
+		case (0x209A<<16)|0x1022:	/* AMD CS5536 */
+		case (0x01BC<<16)|0x10DE:	/* nVidia nForce1 */
+		case (0x0065<<16)|0x10DE:	/* nVidia nForce2 */
+		case (0x0085<<16)|0x10DE:	/* nVidia nForce2 MCP */
+		case (0x00E3<<16)|0x10DE:	/* nVidia nForce2 250 SATA */
+		case (0x00D5<<16)|0x10DE:	/* nVidia nForce3 */
+		case (0x00E5<<16)|0x10DE:	/* nVidia nForce3 Pro */
+		case (0x00EE<<16)|0x10DE:	/* nVidia nForce3 250 SATA */
+		case (0x0035<<16)|0x10DE:	/* nVidia nForce3 MCP */
+		case (0x0053<<16)|0x10DE:	/* nVidia nForce4 */
+		case (0x0054<<16)|0x10DE:	/* nVidia nForce4 SATA */
+		case (0x0055<<16)|0x10DE:	/* nVidia nForce4 SATA */
+		case (0x0266<<16)|0x10DE:	/* nVidia nForce4 430 SATA */
+		case (0x0267<<16)|0x10DE:	/* nVidia nForce 55 MCP SATA */
+		case (0x03EC<<16)|0x10DE:	/* nVidia nForce 61 MCP SATA */
+		case (0x0448<<16)|0x10DE:	/* nVidia nForce 65 MCP SATA */
+		case (0x0560<<16)|0x10DE:	/* nVidia nForce 69 MCP SATA */
+			/*
+			 * Ditto, although it may have a different base
+			 * address for the registers (0x50?).
+			 */
+			/*FALLTHROUGH*/
+		case (0x4376<<16)|0x1002:	/* ATI SB400 PATA */
+		case (0x4379<<16)|0x1002:	/* ATI SB400 SATA */
+		case (0x437a<<16)|0x1002:	/* ATI SB400 SATA */
+			break;
+		case (0x0211<<16)|0x1166:	/* ServerWorks IB6566 */
+			{
+				Pcidev *sb;
+
+				sb = pcimatch(nil, 0x1166, 0x0200);
+				if(sb == nil)
+					break;
+				r = pcicfgr32(sb, 0x64);
+				r &= ~0x2000;
+				pcicfgw32(sb, 0x64, r);
+			}
+			span = 32*1024;
+			break;
+		case (0x0502<<17)|0x100B:	/* NS SC1100/SCx200 */
+		case (0x5229<<16)|0x10B9:	/* ALi M1543 */
+		case (0x5288<<16)|0x10B9:	/* ALi M5288 SATA */
+		case (0x5513<<16)|0x1039:	/* SiS 962 */
+		case (0x0646<<16)|0x1095:	/* CMD 646 */
+		case (0x0571<<16)|0x1106:	/* VIA 82C686 */
+		case (0x2363<<16)|0x197b:	/* JMicron SATA */
+		case (0x1230<<16)|0x8086:	/* 82371FB (PIIX) */
+		case (0x7010<<16)|0x8086:	/* 82371SB (PIIX3) */
+		case (0x7111<<16)|0x8086:	/* 82371[AE]B (PIIX4[E]) */
+		case (0x2411<<16)|0x8086:	/* 82801AA (ICH) */
+		case (0x2421<<16)|0x8086:	/* 82801AB (ICH0) */
+		case (0x244A<<16)|0x8086:	/* 82801BA (ICH2, Mobile) */
+		case (0x244B<<16)|0x8086:	/* 82801BA (ICH2, High-End) */
+		case (0x248A<<16)|0x8086:	/* 82801CA (ICH3, Mobile) */
+		case (0x248B<<16)|0x8086:	/* 82801CA (ICH3, High-End) */
+		case (0x24CA<<16)|0x8086:	/* 82801DBM (ICH4, Mobile) */
+		case (0x24CB<<16)|0x8086:	/* 82801DB (ICH4, High-End) */
+		case (0x24DB<<16)|0x8086:	/* 82801EB (ICH5) */
+		case (0x25A3<<16)|0x8086:	/* 6300ESB (E7210) */
+		case (0x266F<<16)|0x8086:	/* 82801FB (ICH6) */
+		case (0x27DF<<16)|0x8086:	/* 82801G SATA (ICH7) */
+		case (0x27C0<<16)|0x8086:	/* 82801GB SATA AHCI (ICH7) */
+//		case (0x27C4<<16)|0x8086:	/* 82801GBM SATA (ICH7) */
+		case (0x27C5<<16)|0x8086:	/* 82801GBM SATA AHCI (ICH7) */
+		case (0x2920<<16)|0x8086:	/* 82801(IB)/IR/IH/IO SATA IDE (ICH9) */
+		case (0x3a20<<16)|0x8086:	/* 82801JI (ICH10) */
+		case (0x3a26<<16)|0x8086:	/* 82801JI (ICH10) */
+			break;
+		}
+
+		for(channel = 0; channel < 2; channel++){
+			if(pi & (1<<(2*channel))){
+				sdev = ataprobe(p->mem[0+2*channel].bar & ~0x01,
+						p->mem[1+2*channel].bar & ~0x01,
+						p->intl);
+				if(sdev == nil)
+					continue;
+
+				ctlr = sdev->ctlr;
+				if(ispc87415) {
+					ctlr->ienable = pc87415ienable;
+					print("pc87415disable: not yet implemented\n");
+				}
+
+				if(head != nil)
+					tail->next = sdev;
+				else
+					head = sdev;
+				tail = sdev;
+				ctlr->tbdf = p->tbdf;
+			}
+			else if((sdev = legacy[channel]) == nil)
+				continue;
+			else
+				ctlr = sdev->ctlr;
+
+			ctlr->pcidev = p;
+			ctlr->maxio = maxio;
+			ctlr->span = span;
+			if(!(pi & 0x80))
+				continue;
+			ctlr->bmiba = (p->mem[4].bar & ~0x01) + channel*8;
+		}
+	}
+
+if(0){
+	int port;
+	ISAConf isa;
+
+	/*
+	 * Hack for PCMCIA drives.
+	 * This will be tidied once we figure out how the whole
+	 * removeable device thing is going to work.
+	 */
+	memset(&isa, 0, sizeof(isa));
+	isa.port = 0x180;		/* change this for your machine */
+	isa.irq = 11;			/* change this for your machine */
+
+	port = isa.port+0x0C;
+	channel = pcmspecial("MK2001MPL", &isa);
+	if(channel == -1)
+		channel = pcmspecial("SunDisk", &isa);
+	if(channel == -1){
+		isa.irq = 10;
+		channel = pcmspecial("CF", &isa);
+	}
+	if(channel == -1){
+		isa.irq = 10;
+		channel = pcmspecial("OLYMPUS", &isa);
+	}
+	if(channel == -1){
+		port = isa.port+0x204;
+		channel = pcmspecial("ATA/ATAPI", &isa);
+	}
+	if(channel >= 0 && (sdev = ataprobe(isa.port, port, isa.irq)) != nil){
+		if(head != nil)
+			tail->next = sdev;
+		else
+			head = sdev;
+	}
+}
+	return head;
+}
+
+static SDev*
+atalegacy(int port, int irq)
+{
+	return ataprobe(port, port+0x204, irq);
+}
+
+static int
+ataenable(SDev* sdev)
+{
+	Ctlr *ctlr;
+	char name[32];
+
+	ctlr = sdev->ctlr;
+
+	if(ctlr->bmiba){
+#define ALIGN	(4 * 1024)
+		if(ctlr->pcidev != nil)
+			pcisetbme(ctlr->pcidev);
+		ctlr->prdt = mallocalign(Nprd*sizeof(Prd), 4, 0, 4*1024);
+	}
+	snprint(name, sizeof(name), "%s (%s)", sdev->name, sdev->ifc->name);
+	intrenable(ctlr->irq, atainterrupt, ctlr, ctlr->tbdf, name);
+	outb(ctlr->ctlport+Dc, 0);
+	if(ctlr->ienable)
+		ctlr->ienable(ctlr);
+
+	return 1;
+}
+
+static int
+atadisable(SDev *sdev)
+{
+	Ctlr *ctlr;
+	char name[32];
+
+	ctlr = sdev->ctlr;
+	outb(ctlr->ctlport+Dc, Nien);		/* disable interrupts */
+	if (ctlr->idisable)
+		ctlr->idisable(ctlr);
+	snprint(name, sizeof(name), "%s (%s)", sdev->name, sdev->ifc->name);
+	intrdisable(ctlr->irq, atainterrupt, ctlr, ctlr->tbdf, name);
+	if (ctlr->bmiba) {
+		if (ctlr->pcidev)
+			pciclrbme(ctlr->pcidev);
+		free(ctlr->prdt);
+	}
+	return 0;
+}
+
+static int
+atarctl(SDunit* unit, char* p, int l)
+{
+	int n;
+	Ctlr *ctlr;
+	Drive *drive;
+
+	if((ctlr = unit->dev->ctlr) == nil || ctlr->drive[unit->subno] == nil)
+		return 0;
+	drive = ctlr->drive[unit->subno];
+
+	qlock(drive);
+	n = snprint(p, l, "config %4.4uX capabilities %4.4uX",
+		drive->info[Iconfig], drive->info[Icapabilities]);
+	if(drive->dma)
+		n += snprint(p+n, l-n, " dma %8.8uX dmactl %8.8uX",
+			drive->dma, drive->dmactl);
+	if(drive->rwm)
+		n += snprint(p+n, l-n, " rwm %ud rwmctl %ud",
+			drive->rwm, drive->rwmctl);
+	if(drive->flags&Lba48)
+		n += snprint(p+n, l-n, " lba48always %s",
+			(drive->flags&Lba48always) ? "on" : "off");
+	n += snprint(p+n, l-n, "\n");
+	if(drive->sectors){
+		n += snprint(p+n, l-n, "geometry %lld %d",
+			drive->sectors, drive->secsize);
+		if(drive->pkt == 0)
+			n += snprint(p+n, l-n, " %d %d %d",
+				drive->c, drive->h, drive->s);
+		n += snprint(p+n, l-n, "\n");
+	}
+	qunlock(drive);
+
+	return n;
+}
+
+static int
+atawctl(SDunit* unit, Cmdbuf* cb)
+{
+	int period;
+	Ctlr *ctlr;
+	Drive *drive;
+
+	if((ctlr = unit->dev->ctlr) == nil || ctlr->drive[unit->subno] == nil)
+		return 0;
+	drive = ctlr->drive[unit->subno];
+
+	qlock(drive);
+	if(waserror()){
+		qunlock(drive);
+		nexterror();
+	}
+
+	/*
+	 * Dma and rwm control is passive at the moment,
+	 * i.e. it is assumed that the hardware is set up
+	 * correctly already either by the BIOS or when
+	 * the drive was initially identified.
+	 */
+	if(strcmp(cb->f[0], "dma") == 0){
+		if(cb->nf != 2 || drive->dma == 0)
+			error(Ebadctl);
+		if(strcmp(cb->f[1], "on") == 0)
+			drive->dmactl = drive->dma;
+		else if(strcmp(cb->f[1], "off") == 0)
+			drive->dmactl = 0;
+		else
+			error(Ebadctl);
+	}
+	else if(strcmp(cb->f[0], "rwm") == 0){
+		if(cb->nf != 2 || drive->rwm == 0)
+			error(Ebadctl);
+		if(strcmp(cb->f[1], "on") == 0)
+			drive->rwmctl = drive->rwm;
+		else if(strcmp(cb->f[1], "off") == 0)
+			drive->rwmctl = 0;
+		else
+			error(Ebadctl);
+	}
+	else if(strcmp(cb->f[0], "standby") == 0){
+		switch(cb->nf){
+		default:
+			error(Ebadctl);
+		case 2:
+			period = strtol(cb->f[1], 0, 0);
+			if(period && (period < 30 || period > 240*5))
+				error(Ebadctl);
+			period /= 5;
+			break;
+		}
+		if(atastandby(drive, period) != SDok)
+			error(Ebadctl);
+	}
+	else if(strcmp(cb->f[0], "lba48always") == 0){
+		if(cb->nf != 2 || !(drive->flags&Lba48))
+			error(Ebadctl);
+		if(strcmp(cb->f[1], "on") == 0)
+			drive->flags |= Lba48always;
+		else if(strcmp(cb->f[1], "off") == 0)
+			drive->flags &= ~Lba48always;
+		else
+			error(Ebadctl);
+	}
+	else
+		error(Ebadctl);
+	qunlock(drive);
+	poperror();
+
+	return 0;
+}
+
+SDifc sdataifc = {
+	"ata",				/* name */
+
+	atapnp,				/* pnp */
+	atalegacy,			/* legacy */
+	ataenable,			/* enable */
+	atadisable,			/* disable */
+
+	scsiverify,			/* verify */
+	scsionline,			/* online */
+	atario,				/* rio */
+	atarctl,			/* rctl */
+	atawctl,			/* wctl */
+
+	scsibio,			/* bio */
+	ataprobew,			/* probe */
+	ataclear,			/* clear */
+	atastat,			/* rtopctl */
+	nil,				/* wtopctl */
+};