[libata] C/H/S support, for older devices

drivers/scsi/libata-core.c

@@ -52,6 +52,7 @@
 static unsigned int ata_busy_sleep (struct ata_port *ap,
 				    unsigned long tmout_pat,
 			    	    unsigned long tmout);
+static void ata_dev_init_params(struct ata_port *ap, struct ata_device *dev);
 static void ata_set_mode(struct ata_port *ap);
 static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev);
 static unsigned int ata_get_mode_mask(struct ata_port *ap, int shift);
@@ -1008,7 +1009,7 @@ static inline void ata_dump_id(struct ata_device *dev)
 static void ata_dev_identify(struct ata_port *ap, unsigned int device)
 {
 	struct ata_device *dev = &ap->device[device];
-	unsigned int i;
+	unsigned int major_version;
 	u16 tmp;
 	unsigned long xfer_modes;
 	u8 status;
@@ -1106,9 +1107,9 @@ retry:
 	 * common ATA, ATAPI feature tests
 	 */
 
-	/* we require LBA and DMA support (bits 8 & 9 of word 49) */
+	/* we require DMA support (bits 8 of word 49) */
-	if (!ata_id_has_dma(dev->id) || !ata_id_has_lba(dev->id)) {
+	if (!ata_id_has_dma(dev->id)) {
-		printk(KERN_DEBUG "ata%u: no dma/lba\n", ap->id);
+		printk(KERN_DEBUG "ata%u: no dma\n", ap->id);
 		goto err_out_nosup;
 	}
 
@@ -1128,32 +1129,69 @@ retry:
 		if (!ata_id_is_ata(dev->id))	/* sanity check */
 			goto err_out_nosup;
 
+		/* get major version */
 		tmp = dev->id[ATA_ID_MAJOR_VER];
-		for (i = 14; i >= 1; i--)
+		for (major_version = 14; major_version >= 1; major_version--)
-			if (tmp & (1 << i))
+			if (tmp & (1 << major_version))
 				break;
 
-		/* we require at least ATA-3 */
+		/*
-		if (i < 3) {
+		 * The exact sequence expected by certain pre-ATA4 drives is:
-			printk(KERN_DEBUG "ata%u: no ATA-3\n", ap->id);
+		 * SRST RESET
-			goto err_out_nosup;
+		 * IDENTIFY
-		}
+		 * INITIALIZE DEVICE PARAMETERS
+		 * anything else..
+		 * Some drives were very specific about that exact sequence.
+		 */
+		if (major_version < 4 || (!ata_id_has_lba(dev->id)))
+			ata_dev_init_params(ap, dev);
+
+		if (ata_id_has_lba(dev->id)) {
+			dev->flags |= ATA_DFLAG_LBA;
+
+			if (ata_id_has_lba48(dev->id)) {
+				dev->flags |= ATA_DFLAG_LBA48;
+				dev->n_sectors = ata_id_u64(dev->id, 100);
+			} else {
+				dev->n_sectors = ata_id_u32(dev->id, 60);
+			}
+
+			/* print device info to dmesg */
+			printk(KERN_INFO "ata%u: dev %u ATA-%d, max %s, %Lu sectors:%s\n",
+			       ap->id, device,
+			       major_version,
+			       ata_mode_string(xfer_modes),
+			       (unsigned long long)dev->n_sectors,
+			       dev->flags & ATA_DFLAG_LBA48 ? " LBA48" : " LBA");
+		} else { 
+			/* CHS */
+
+			/* Default translation */
+			dev->cylinders	= dev->id[1];
+			dev->heads	= dev->id[3];
+			dev->sectors	= dev->id[6];
+			dev->n_sectors	= dev->cylinders * dev->heads * dev->sectors;
+
+			if (ata_id_current_chs_valid(dev->id)) {
+				/* Current CHS translation is valid. */
+				dev->cylinders = dev->id[54];
+				dev->heads     = dev->id[55];
+				dev->sectors   = dev->id[56];
+				
+				dev->n_sectors = ata_id_u32(dev->id, 57);
+			}
+
+			/* print device info to dmesg */
+			printk(KERN_INFO "ata%u: dev %u ATA-%d, max %s, %Lu sectors: CHS %d/%d/%d\n",
+			       ap->id, device,
+			       major_version,
+			       ata_mode_string(xfer_modes),
+			       (unsigned long long)dev->n_sectors,
+			       (int)dev->cylinders, (int)dev->heads, (int)dev->sectors);
 
-		if (ata_id_has_lba48(dev->id)) {
-			dev->flags |= ATA_DFLAG_LBA48;
-			dev->n_sectors = ata_id_u64(dev->id, 100);
-		} else {
-			dev->n_sectors = ata_id_u32(dev->id, 60);
 		}
 
 		ap->host->max_cmd_len = 16;
-
-		/* print device info to dmesg */
-		printk(KERN_INFO "ata%u: dev %u ATA, max %s, %Lu sectors:%s\n",
-		       ap->id, device,
-		       ata_mode_string(xfer_modes),
-		       (unsigned long long)dev->n_sectors,
-		       dev->flags & ATA_DFLAG_LBA48 ? " lba48" : "");
 	}
 
 	/* ATAPI-specific feature tests */
@@ -1946,6 +1984,54 @@ static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
 	DPRINTK("EXIT\n");
 }
 
+/**
+ *	ata_dev_init_params - Issue INIT DEV PARAMS command
+ *	@ap: Port associated with device @dev
+ *	@dev: Device to which command will be sent
+ *
+ *	LOCKING:
+ */
+
+static void ata_dev_init_params(struct ata_port *ap, struct ata_device *dev)
+{
+	DECLARE_COMPLETION(wait);
+	struct ata_queued_cmd *qc;
+	int rc;
+	unsigned long flags;
+	u16 sectors = dev->id[6];
+	u16 heads   = dev->id[3];
+
+	/* Number of sectors per track 1-255. Number of heads 1-16 */
+	if (sectors < 1 || sectors > 255 || heads < 1 || heads > 16)
+		return;
+
+	/* set up init dev params taskfile */
+	DPRINTK("init dev params \n");
+
+	qc = ata_qc_new_init(ap, dev);
+	BUG_ON(qc == NULL);
+
+	qc->tf.command = ATA_CMD_INIT_DEV_PARAMS;
+	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	qc->tf.protocol = ATA_PROT_NODATA;
+	qc->tf.nsect = sectors;
+	qc->tf.device |= (heads - 1) & 0x0f; /* max head = num. of heads - 1 */
+
+	qc->waiting = &wait;
+	qc->complete_fn = ata_qc_complete_noop;
+
+	spin_lock_irqsave(&ap->host_set->lock, flags);
+	rc = ata_qc_issue(qc);
+	spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+	if (rc)
+		ata_port_disable(ap);
+	else
+		wait_for_completion(&wait);
+
+	DPRINTK("EXIT\n");
+}
+
 /**
  *	ata_sg_clean -
  *	@qc:
@@ -2736,8 +2822,12 @@ struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
 
 		ata_tf_init(ap, &qc->tf, dev->devno);
 
-		if (dev->flags & ATA_DFLAG_LBA48)
+		if (dev->flags & ATA_DFLAG_LBA) {
-			qc->tf.flags |= ATA_TFLAG_LBA48;
+			qc->tf.flags |= ATA_TFLAG_LBA;
+
+			if (dev->flags & ATA_DFLAG_LBA48)
+				qc->tf.flags |= ATA_TFLAG_LBA48;
+		}
 	}
 
 	return qc;

drivers/scsi/libata-scsi.c

@@ -435,78 +435,108 @@ static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 {
 	struct ata_taskfile *tf = &qc->tf;
+	struct ata_device *dev = qc->dev;
+	unsigned int lba   = tf->flags & ATA_TFLAG_LBA;
 	unsigned int lba48 = tf->flags & ATA_TFLAG_LBA48;
 	u64 dev_sectors = qc->dev->n_sectors;
-	u64 sect = 0;
+	u64 block = 0;
-	u32 n_sect = 0;
+	u32 n_block = 0;
 
 	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
 	tf->protocol = ATA_PROT_NODATA;
-	tf->device |= ATA_LBA;
 
 	if (scsicmd[0] == VERIFY) {
-		sect |= ((u64)scsicmd[2]) << 24;
+		block |= ((u64)scsicmd[2]) << 24;
-		sect |= ((u64)scsicmd[3]) << 16;
+		block |= ((u64)scsicmd[3]) << 16;
-		sect |= ((u64)scsicmd[4]) << 8;
+		block |= ((u64)scsicmd[4]) << 8;
-		sect |= ((u64)scsicmd[5]);
+		block |= ((u64)scsicmd[5]);
 
-		n_sect |= ((u32)scsicmd[7]) << 8;
+		n_block |= ((u32)scsicmd[7]) << 8;
-		n_sect |= ((u32)scsicmd[8]);
+		n_block |= ((u32)scsicmd[8]);
 	}
 
 	else if (scsicmd[0] == VERIFY_16) {
-		sect |= ((u64)scsicmd[2]) << 56;
+		block |= ((u64)scsicmd[2]) << 56;
-		sect |= ((u64)scsicmd[3]) << 48;
+		block |= ((u64)scsicmd[3]) << 48;
-		sect |= ((u64)scsicmd[4]) << 40;
+		block |= ((u64)scsicmd[4]) << 40;
-		sect |= ((u64)scsicmd[5]) << 32;
+		block |= ((u64)scsicmd[5]) << 32;
-		sect |= ((u64)scsicmd[6]) << 24;
+		block |= ((u64)scsicmd[6]) << 24;
-		sect |= ((u64)scsicmd[7]) << 16;
+		block |= ((u64)scsicmd[7]) << 16;
-		sect |= ((u64)scsicmd[8]) << 8;
+		block |= ((u64)scsicmd[8]) << 8;
-		sect |= ((u64)scsicmd[9]);
+		block |= ((u64)scsicmd[9]);
 
-		n_sect |= ((u32)scsicmd[10]) << 24;
+		n_block |= ((u32)scsicmd[10]) << 24;
-		n_sect |= ((u32)scsicmd[11]) << 16;
+		n_block |= ((u32)scsicmd[11]) << 16;
-		n_sect |= ((u32)scsicmd[12]) << 8;
+		n_block |= ((u32)scsicmd[12]) << 8;
-		n_sect |= ((u32)scsicmd[13]);
+		n_block |= ((u32)scsicmd[13]);
 	}
 
 	else
 		return 1;
 
-	if (!n_sect)
+	if (!n_block)
 		return 1;
-	if (sect >= dev_sectors)
+	if (block >= dev_sectors)
 		return 1;
-	if ((sect + n_sect) > dev_sectors)
+	if ((block + n_block) > dev_sectors)
 		return 1;
 	if (lba48) {
-		if (n_sect > (64 * 1024))
+		if (n_block > (64 * 1024))
 			return 1;
 	} else {
-		if (n_sect > 256)
+		if (n_block > 256)
 			return 1;
 	}
 
-	if (lba48) {
+	if (lba) {
-		tf->command = ATA_CMD_VERIFY_EXT;
+		if (lba48) {
+			tf->command = ATA_CMD_VERIFY_EXT;
 
-		tf->hob_nsect = (n_sect >> 8) & 0xff;
+			tf->hob_nsect = (n_block >> 8) & 0xff;
 
-		tf->hob_lbah = (sect >> 40) & 0xff;
+			tf->hob_lbah = (block >> 40) & 0xff;
-		tf->hob_lbam = (sect >> 32) & 0xff;
+			tf->hob_lbam = (block >> 32) & 0xff;
-		tf->hob_lbal = (sect >> 24) & 0xff;
+			tf->hob_lbal = (block >> 24) & 0xff;
+		} else {
+			tf->command = ATA_CMD_VERIFY;
+
+			tf->device |= (block >> 24) & 0xf;
+		}
+
+		tf->nsect = n_block & 0xff;
+
+		tf->lbah = (block >> 16) & 0xff;
+		tf->lbam = (block >> 8) & 0xff;
+		tf->lbal = block & 0xff;
+
+		tf->device |= ATA_LBA;
 	} else {
+		/* CHS */
+		u32 sect, head, cyl, track;
+
+		/* Convert LBA to CHS */
+		track = (u32)block / dev->sectors;
+		cyl   = track / dev->heads;
+		head  = track % dev->heads;
+		sect  = (u32)block % dev->sectors + 1;
+
+		DPRINTK("block[%u] track[%u] cyl[%u] head[%u] sect[%u] \n", (u32)block, track, cyl, head, sect);
+		
+		/* Check whether the converted CHS can fit. 
+		   Cylinder: 0-65535 
+		   Head: 0-15
+		   Sector: 1-255*/
+		if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect)) 
+			return 1;
+		
 		tf->command = ATA_CMD_VERIFY;
-
+		tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
-		tf->device |= (sect >> 24) & 0xf;
+		tf->lbal = sect;
+		tf->lbam = cyl;
+		tf->lbah = cyl >> 8;
+		tf->device |= head;
 	}
 
-	tf->nsect = n_sect & 0xff;
-
-	tf->lbah = (sect >> 16) & 0xff;
-	tf->lbam = (sect >> 8) & 0xff;
-	tf->lbal = sect & 0xff;
-
 	return 0;
 }
 
@@ -533,11 +563,14 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 {
 	struct ata_taskfile *tf = &qc->tf;
+	struct ata_device *dev = qc->dev;
+	unsigned int lba   = tf->flags & ATA_TFLAG_LBA;
 	unsigned int lba48 = tf->flags & ATA_TFLAG_LBA48;
+	u64 block = 0;
+	u32 n_block = 0;
 
 	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
 	tf->protocol = qc->dev->xfer_protocol;
-	tf->device |= ATA_LBA;
 
 	if (scsicmd[0] == READ_10 || scsicmd[0] == READ_6 ||
 	    scsicmd[0] == READ_16) {
@@ -547,80 +580,111 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 		tf->flags |= ATA_TFLAG_WRITE;
 	}
 
+	/* Calculate the SCSI LBA and transfer length. */
 	if (scsicmd[0] == READ_10 || scsicmd[0] == WRITE_10) {
-		if (lba48) {
+		block |= ((u64)scsicmd[2]) << 24;
-			tf->hob_nsect = scsicmd[7];
+		block |= ((u64)scsicmd[3]) << 16;
-			tf->hob_lbal = scsicmd[2];
+		block |= ((u64)scsicmd[4]) << 8;
+		block |= ((u64)scsicmd[5]);
 
-			qc->nsect = ((unsigned int)scsicmd[7] << 8) |
+		n_block |= ((u32)scsicmd[7]) << 8;
-					scsicmd[8];
+		n_block |= ((u32)scsicmd[8]);
-		} else {
-			/* if we don't support LBA48 addressing, the request
-			 * -may- be too large. */
-			if ((scsicmd[2] & 0xf0) || scsicmd[7])
-				return 1;
-
-			/* stores LBA27:24 in lower 4 bits of device reg */
-			tf->device |= scsicmd[2];
-
-			qc->nsect = scsicmd[8];
-		}
-
-		tf->nsect = scsicmd[8];
-		tf->lbal = scsicmd[5];
-		tf->lbam = scsicmd[4];
-		tf->lbah = scsicmd[3];
 
 		VPRINTK("ten-byte command\n");
-		return 0;
+	} else if (scsicmd[0] == READ_6 || scsicmd[0] == WRITE_6) {
-	}
+		block |= ((u64)scsicmd[2]) << 8;
-
+		block |= ((u64)scsicmd[3]);
-	if (scsicmd[0] == READ_6 || scsicmd[0] == WRITE_6) {
+		n_block |= ((u32)scsicmd[4]);
-		qc->nsect = tf->nsect = scsicmd[4];
+	
-		tf->lbal = scsicmd[3];
-		tf->lbam = scsicmd[2];
-		tf->lbah = scsicmd[1] & 0x1f; /* mask out reserved bits */
-
 		VPRINTK("six-byte command\n");
-		return 0;
+	} else if (scsicmd[0] == READ_16 || scsicmd[0] == WRITE_16) {
-	}
+		block |= ((u64)scsicmd[2]) << 56;
+		block |= ((u64)scsicmd[3]) << 48;
+		block |= ((u64)scsicmd[4]) << 40;
+		block |= ((u64)scsicmd[5]) << 32;
+		block |= ((u64)scsicmd[6]) << 24;
+		block |= ((u64)scsicmd[7]) << 16;
+		block |= ((u64)scsicmd[8]) << 8;
+		block |= ((u64)scsicmd[9]);
 
-	if (scsicmd[0] == READ_16 || scsicmd[0] == WRITE_16) {
+		n_block |= ((u32)scsicmd[10]) << 24;
-		/* rule out impossible LBAs and sector counts */
+		n_block |= ((u32)scsicmd[11]) << 16;
-		if (scsicmd[2] || scsicmd[3] || scsicmd[10] || scsicmd[11])
+		n_block |= ((u32)scsicmd[12]) << 8;
-			return 1;
+		n_block |= ((u32)scsicmd[13]);
-
-		if (lba48) {
-			tf->hob_nsect = scsicmd[12];
-			tf->hob_lbal = scsicmd[6];
-			tf->hob_lbam = scsicmd[5];
-			tf->hob_lbah = scsicmd[4];
-
-			qc->nsect = ((unsigned int)scsicmd[12] << 8) |
-					scsicmd[13];
-		} else {
-			/* once again, filter out impossible non-zero values */
-			if (scsicmd[4] || scsicmd[5] || scsicmd[12] ||
-			    (scsicmd[6] & 0xf0))
-				return 1;
-
-			/* stores LBA27:24 in lower 4 bits of device reg */
-			tf->device |= scsicmd[6];
-
-			qc->nsect = scsicmd[13];
-		}
-
-		tf->nsect = scsicmd[13];
-		tf->lbal = scsicmd[9];
-		tf->lbam = scsicmd[8];
-		tf->lbah = scsicmd[7];
 
 		VPRINTK("sixteen-byte command\n");
-		return 0;
+	} else {
+		DPRINTK("no-byte command\n");
+		return 1;
 	}
 
-	DPRINTK("no-byte command\n");
+	/* Check and compose ATA command */
-	return 1;
+	if (!n_block)
+		/* In ATA, sector count 0 means 256 or 65536 sectors, not 0 sectors. */
+		return 1;
+
+	if (lba) {
+		if (lba48) {
+			/* The request -may- be too large for LBA48. */
+			if ((block >> 48) || (n_block > 65536))
+				return 1;
+
+			tf->hob_nsect = (n_block >> 8) & 0xff;
+
+			tf->hob_lbah = (block >> 40) & 0xff;
+			tf->hob_lbam = (block >> 32) & 0xff;
+			tf->hob_lbal = (block >> 24) & 0xff;
+		} else { 
+			/* LBA28 */
+
+			/* The request -may- be too large for LBA28. */
+			if ((block >> 28) || (n_block > 256))
+				return 1;
+
+			tf->device |= (block >> 24) & 0xf;
+		}
+	
+		qc->nsect = n_block;
+		tf->nsect = n_block & 0xff;
+
+		tf->lbah = (block >> 16) & 0xff;
+		tf->lbam = (block >> 8) & 0xff;
+		tf->lbal = block & 0xff;
+
+		tf->device |= ATA_LBA;
+	} else { 
+		/* CHS */
+		u32 sect, head, cyl, track;
+
+		/* The request -may- be too large for CHS addressing. */
+		if ((block >> 28) || (n_block > 256))
+			return 1;
+			
+		/* Convert LBA to CHS */
+		track = (u32)block / dev->sectors;
+		cyl   = track / dev->heads;
+		head  = track % dev->heads;
+		sect  = (u32)block % dev->sectors + 1;
+
+		DPRINTK("block[%u] track[%u] cyl[%u] head[%u] sect[%u] \n", 
+			(u32)block, track, cyl, head, sect);
+		
+		/* Check whether the converted CHS can fit. 
+		   Cylinder: 0-65535 
+		   Head: 0-15
+		   Sector: 1-255*/
+		if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect)) 
+			return 1;
+		
+		qc->nsect = n_block;
+		tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
+		tf->lbal = sect;
+		tf->lbam = cyl;
+		tf->lbah = cyl >> 8;
+		tf->device |= head;
+	}
+
+	return 0;
 }
 
 static int ata_scsi_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
@@ -1167,10 +1231,20 @@ unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf,
 
 	VPRINTK("ENTER\n");
 
-	if (ata_id_has_lba48(args->id))
+	if (ata_id_has_lba(args->id)) {
-		n_sectors = ata_id_u64(args->id, 100);
+		if (ata_id_has_lba48(args->id))
-	else
+			n_sectors = ata_id_u64(args->id, 100);
-		n_sectors = ata_id_u32(args->id, 60);
+		else
+			n_sectors = ata_id_u32(args->id, 60);
+	} else {
+		/* CHS default translation */
+		n_sectors = args->id[1] * args->id[3] * args->id[6];
+
+		if (ata_id_current_chs_valid(args->id))
+			/* CHS current translation */
+			n_sectors = ata_id_u32(args->id, 57);
+	}
+
 	n_sectors--;		/* ATA TotalUserSectors - 1 */
 
 	tmp = n_sectors;	/* note: truncates, if lba48 */

include/linux/ata.h

@@ -125,6 +125,7 @@ enum {
 	ATA_CMD_PACKET		= 0xA0,
 	ATA_CMD_VERIFY		= 0x40,
 	ATA_CMD_VERIFY_EXT	= 0x42,
+	ATA_CMD_INIT_DEV_PARAMS	= 0x91,
 
 	/* SETFEATURES stuff */
 	SETFEATURES_XFER	= 0x03,
@@ -174,6 +175,7 @@ enum {
 	ATA_TFLAG_ISADDR	= (1 << 1), /* enable r/w to nsect/lba regs */
 	ATA_TFLAG_DEVICE	= (1 << 2), /* enable r/w to device reg */
 	ATA_TFLAG_WRITE		= (1 << 3), /* data dir: host->dev==1 (write) */
+	ATA_TFLAG_LBA		= (1 << 4), /* enable LBA */
 };
 
 enum ata_tf_protocols {
@@ -242,6 +244,18 @@ struct ata_taskfile {
 	  ((u64) (id)[(n) + 1] << 16) |	\
 	  ((u64) (id)[(n) + 0]) )
 
+static inline int ata_id_current_chs_valid(u16 *id)
+{
+	/* For ATA-1 devices, if the INITIALIZE DEVICE PARAMETERS command 
+	   has not been issued to the device then the values of 
+	   id[54] to id[56] are vendor specific. */
+	return (id[53] & 0x01) && /* Current translation valid */
+		id[54] &&  /* cylinders in current translation */
+		id[55] &&  /* heads in current translation */
+		id[55] <= 16 &&
+		id[56];    /* sectors in current translation */
+}
+
 static inline int atapi_cdb_len(u16 *dev_id)
 {
 	u16 tmp = dev_id[0] & 0x3;

include/linux/libata.h

@@ -95,6 +95,7 @@ enum {
 	ATA_DFLAG_LBA48		= (1 << 0), /* device supports LBA48 */
 	ATA_DFLAG_PIO		= (1 << 1), /* device currently in PIO mode */
 	ATA_DFLAG_LOCK_SECTORS	= (1 << 2), /* don't adjust max_sectors */
+	ATA_DFLAG_LBA		= (1 << 3), /* device supports LBA */
 
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */
@@ -278,6 +279,11 @@ struct ata_device {
 	u8			xfer_protocol;	/* taskfile xfer protocol */
 	u8			read_cmd;	/* opcode to use on read */
 	u8			write_cmd;	/* opcode to use on write */
+
+	/* for CHS addressing */
+	u16			cylinders;	/* Number of cylinders */
+	u16			heads;		/* Number of heads */
+	u16			sectors;	/* Number of sectors per track */
 };
 
 struct ata_port {