[libata] ATAPI work - cdb len, new taskfile protocol, cleanups

* new helper atapi_cdb_len() in linux/ata.h, use it after
IDENTIFY PACKET DEVICE command completes
* add new taskfile protocol ATA_PROT_ATAPI_NODATA
* store scsi cdb in ata_queued_cmd.  This removes another dependence
on the scsi layer, and enables us to issue an internal REQUEST SENSE.
* store cdb len in ata_port
* new constant ATAPI_CDB_LEN for max cdb length
* move ATA taskfile and SCSI cdb near the top of ata_queued_cmd, for
better cacheline friendliness.

drivers/scsi/libata-core.c

@@ -1099,10 +1099,13 @@ static void ata_dev_identify(struct ata_port *ap, unsigned int device)
 		if (ata_id_is_ata(dev))		/* sanity check */
 			goto err_out_nosup;
 
-		/* see if 16-byte commands supported */
-		tmp = dev->id[0] & 0x3;
-		if (tmp == 1)
-			ap->host->max_cmd_len = 16;
+		rc = atapi_cdb_len(dev->id);
+		if ((rc < 12) || (rc > ATAPI_CDB_LEN)) {
+			printk(KERN_WARNING "ata%u: unsupported CDB len\n", ap->id);
+			goto err_out_nosup;
+		}
+		ap->cdb_len = (unsigned int) rc;
+		ap->host->max_cmd_len = (unsigned char) ap->cdb_len;
 
 		/* print device info to dmesg */
 		printk(KERN_INFO "ata%u: dev %u ATAPI, max %s\n",
@@ -2265,7 +2268,6 @@ static void ata_qc_timeout(struct ata_queued_cmd *qc)
 
 		/* fall through */
 
-	case ATA_PROT_NODATA:
 	default:
 		ata_altstatus(ap);
 		drv_stat = ata_chk_status(ap);
@@ -2520,6 +2522,11 @@ int ata_qc_issue_prot(struct ata_queued_cmd *qc)
 		queue_work(ata_wq, &ap->packet_task);
 		break;
 
+	case ATA_PROT_ATAPI_NODATA:
+		ata_tf_to_host_nolock(ap, &qc->tf);
+		queue_work(ata_wq, &ap->packet_task);
+		break;
+
 	case ATA_PROT_ATAPI_DMA:
 		ap->ops->tf_load(ap, &qc->tf);	 /* load tf registers */
 		ap->ops->bmdma_setup(qc);	    /* set up bmdma */
@@ -2685,6 +2692,7 @@ inline unsigned int ata_host_intr (struct ata_port *ap,
 
 		/* fall through */
 
+	case ATA_PROT_ATAPI_NODATA:
 	case ATA_PROT_NODATA:
 		/* check altstatus */
 		status = ata_altstatus(ap);
@@ -2795,19 +2803,20 @@ static void atapi_packet_task(void *_data)
 
 	/* make sure DRQ is set */
 	status = ata_chk_status(ap);
-	if ((status & ATA_DRQ) == 0)
+	if ((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ)
 		goto err_out;
 
 	/* send SCSI cdb */
 	DPRINTK("send cdb\n");
-	ata_data_xfer(ap, qc->scsicmd->cmnd, ap->host->max_cmd_len, 1);
+	assert(ap->cdb_len >= 12);
+	ata_data_xfer(ap, qc->cdb, ap->cdb_len, 1);
 
 	/* if we are DMA'ing, irq handler takes over from here */
 	if (qc->tf.protocol == ATA_PROT_ATAPI_DMA)
 		ap->ops->bmdma_start(qc);	    /* initiate bmdma */
 
 	/* non-data commands are also handled via irq */
-	else if (qc->scsicmd->sc_data_direction == SCSI_DATA_NONE) {
+	else if (qc->tf.protocol == ATA_PROT_ATAPI_NODATA) {
 		/* do nothing */
 	}
 

drivers/scsi/libata-scsi.c

@@ -1002,6 +1002,9 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 	struct scsi_cmnd *cmd = qc->scsicmd;
 	struct ata_device *dev = qc->dev;
 	int using_pio = (dev->flags & ATA_DFLAG_PIO);
+	int nodata = (cmd->sc_data_direction == SCSI_DATA_NONE);
+
+	memcpy(&qc->cdb, scsicmd, qc->ap->cdb_len);
 
 	qc->complete_fn = atapi_qc_complete;
 
@@ -1013,18 +1016,18 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 
 	qc->tf.command = ATA_CMD_PACKET;
 
-	/* no data - interrupt-driven */
-	if (cmd->sc_data_direction == SCSI_DATA_NONE)
-		qc->tf.protocol = ATA_PROT_ATAPI;
-
-	/* PIO data xfer */
-	else if (using_pio) {
-		qc->tf.protocol = ATA_PROT_ATAPI;
+	/* no data, or PIO data xfer */
+	if (using_pio || nodata) {
+		if (nodata)
+			qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
+		else
+			qc->tf.protocol = ATA_PROT_ATAPI;
 		qc->tf.lbam = (8 * 1024) & 0xff;
 		qc->tf.lbah = (8 * 1024) >> 8;
+	}
 
 	/* DMA data xfer */
-	} else {
+	else {
 		qc->tf.protocol = ATA_PROT_ATAPI_DMA;
 		qc->tf.feature |= ATAPI_PKT_DMA;
 

include/linux/ata.h

@@ -147,6 +147,7 @@ enum {
 	ATAPI_PKT_DMA		= (1 << 0),
 	ATAPI_DMADIR		= (1 << 2),	/* ATAPI data dir:
 						   0=to device, 1=to host */
+	ATAPI_CDB_LEN		= 16,
 
 	/* cable types */
 	ATA_CBL_NONE		= 0,
@@ -176,7 +177,8 @@ enum ata_tf_protocols {
 	ATA_PROT_PIO,		/* PIO single sector */
 	ATA_PROT_PIO_MULT,	/* PIO multiple sector */
 	ATA_PROT_DMA,		/* DMA */
-	ATA_PROT_ATAPI,		/* packet command */
+	ATA_PROT_ATAPI,		/* packet command, PIO data xfer*/
+	ATA_PROT_ATAPI_NODATA,	/* packet command, no data */
 	ATA_PROT_ATAPI_DMA,	/* packet command with special DMA sauce */
 };
 
@@ -227,9 +229,20 @@ struct ata_taskfile {
 	  ((u64) dev->id[(n) + 1] << 16) |	\
 	  ((u64) dev->id[(n) + 0]) )
 
+static inline int atapi_cdb_len(u16 *dev_id)
+{
+	u16 tmp = dev_id[0] & 0x3;
+	switch (tmp) {
+	case 0:		return 12;
+	case 1:		return 16;
+	default:	return -1;
+	}
+}
+
 static inline int is_atapi_taskfile(struct ata_taskfile *tf)
 {
 	return (tf->protocol == ATA_PROT_ATAPI) ||
+	       (tf->protocol == ATA_PROT_ATAPI_NODATA) ||
 	       (tf->protocol == ATA_PROT_ATAPI_DMA);
 }
 

include/linux/libata.h

@@ -218,6 +218,9 @@ struct ata_queued_cmd {
 	struct scsi_cmnd	*scsicmd;
 	void			(*scsidone)(struct scsi_cmnd *);
 
+	struct ata_taskfile	tf;
+	u8			cdb[ATAPI_CDB_LEN];
+
 	unsigned long		flags;		/* ATA_QCFLAG_xxx */
 	unsigned int		tag;
 	unsigned int		n_elem;
@@ -229,7 +232,6 @@ struct ata_queued_cmd {
 	unsigned int		cursg;
 	unsigned int		cursg_ofs;
 
-	struct ata_taskfile	tf;
 	struct scatterlist	sgent;
 	void			*buf_virt;
 
@@ -285,6 +287,7 @@ struct ata_port {
 	unsigned int		mwdma_mask;
 	unsigned int		udma_mask;
 	unsigned int		cbl;	/* cable type; ATA_CBL_xxx */
+	unsigned int		cdb_len;
 
 	struct ata_device	device[ATA_MAX_DEVICES];