[libata] consolidate data transfer mode handling

The various ways you can send data to/from your ATA device is
known as the ATA taskfile protocol:  PIO single sector, PIO
multiple sector, DMA, DMA TCQ, DMA NCQ, ...

Prior to this change, the data direction (read/write) was encoded
implicitly into the ATA_PROT_xxx value itself.  This increased
complexity in some areas, and inhibited flexibility in others.

This change separates data direction from taskfile protocol, and also
moves the data direction flag (ATA_QCFLAG_WRITE) down to a lower
level (ATA_TFLAG_WRITE).

drivers/scsi/libata-core.c

@@ -444,8 +444,7 @@ static int ata_prot_to_cmd(int protocol, int lba48)
 	int rcmd = 0, wcmd = 0;
 
 	switch (protocol) {
-	case ATA_PROT_PIO_READ:
-	case ATA_PROT_PIO_WRITE:
+	case ATA_PROT_PIO:
 		if (lba48) {
 			rcmd = ATA_CMD_PIO_READ_EXT;
 			wcmd = ATA_CMD_PIO_WRITE_EXT;
@@ -455,8 +454,7 @@ static int ata_prot_to_cmd(int protocol, int lba48)
 		}
 		break;
 
-	case ATA_PROT_DMA_READ:
-	case ATA_PROT_DMA_WRITE:
+	case ATA_PROT_DMA:
 		if (lba48) {
 			rcmd = ATA_CMD_READ_EXT;
 			wcmd = ATA_CMD_WRITE_EXT;
@@ -479,13 +477,10 @@ static void ata_dev_set_protocol(struct ata_device *dev)
 	int lba48 = (dev->flags & ATA_DFLAG_LBA48);
 	int proto, cmd;
 
-	if (pio) {
-		proto = dev->r_protocol = ATA_PROT_PIO_READ;
-		dev->w_protocol = ATA_PROT_PIO_WRITE;
-	} else {
-		proto = dev->r_protocol = ATA_PROT_DMA_READ;
-		dev->w_protocol = ATA_PROT_DMA_WRITE;
-	}
+	if (pio)
+		proto = dev->xfer_protocol = ATA_PROT_PIO;
+	else
+		proto = dev->xfer_protocol = ATA_PROT_DMA;
 
 	cmd = ata_prot_to_cmd(proto, lba48);
 	if (cmd < 0)
@@ -899,7 +894,7 @@ static void ata_dev_identify(struct ata_port *ap, unsigned int device)
 retry:
 	ata_tf_init(ap, &tf, device);
 	tf.ctl |= ATA_NIEN;
-	tf.protocol = ATA_PROT_PIO_READ;
+	tf.protocol = ATA_PROT_PIO;
 
 	if (dev->class == ATA_DEV_ATA) {
 		tf.command = ATA_CMD_ID_ATA;
@@ -1803,7 +1798,7 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
 	sg_dma_address(sg) = dma_address;
 
 	DPRINTK("mapped buffer of %d bytes for %s\n", cmd->request_bufflen,
-		qc->flags & ATA_QCFLAG_WRITE ? "write" : "read");
+		qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
 
 	return 0;
 }
@@ -1904,8 +1899,7 @@ static void ata_pio_start (struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
 
-	assert((qc->tf.protocol == ATA_PROT_PIO_READ) ||
-	       (qc->tf.protocol == ATA_PROT_PIO_WRITE));
+	assert(qc->tf.protocol == ATA_PROT_PIO);
 
 	qc->flags |= ATA_QCFLAG_POLL;
 	qc->tf.ctl |= ATA_NIEN;	/* disable interrupts */
@@ -2025,12 +2019,12 @@ static void ata_pio_sector(struct ata_port *ap)
 		}
 
 	DPRINTK("data %s, drv_stat 0x%X\n",
-		qc->flags & ATA_QCFLAG_WRITE ? "write" : "read",
+		qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read",
 		status);
 
 	/* do the actual data transfer */
 	/* FIXME: mmio-ize */
-	if (qc->flags & ATA_QCFLAG_WRITE)
+	if (qc->tf.flags & ATA_TFLAG_WRITE)
 		outsl(ap->ioaddr.data_addr, buf, ATA_SECT_DWORDS);
 	else
 		insl(ap->ioaddr.data_addr, buf, ATA_SECT_DWORDS);
@@ -2095,8 +2089,7 @@ void ata_eng_timeout(struct ata_port *ap)
 	qc->scsidone = scsi_finish_command;
 
 	switch (qc->tf.protocol) {
-	case ATA_PROT_DMA_READ:
-	case ATA_PROT_DMA_WRITE:
+	case ATA_PROT_DMA:
 		if (ap->flags & ATA_FLAG_MMIO) {
 			void *mmio = (void *) ap->ioaddr.bmdma_addr;
 			host_stat = readb(mmio + ATA_DMA_STATUS);
@@ -2320,7 +2313,7 @@ int ata_qc_issue(struct ata_queued_cmd *qc)
 void ata_bmdma_start_mmio (struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
-	unsigned int rw = (qc->flags & ATA_QCFLAG_WRITE);
+	unsigned int rw = (qc->tf.flags & ATA_TFLAG_WRITE);
 	u8 host_stat, dmactl;
 	void *mmio = (void *) ap->ioaddr.bmdma_addr;
 
@@ -2369,7 +2362,7 @@ void ata_bmdma_start_mmio (struct ata_queued_cmd *qc)
 void ata_bmdma_start_pio (struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
-	unsigned int rw = (qc->flags & ATA_QCFLAG_WRITE);
+	unsigned int rw = (qc->tf.flags & ATA_TFLAG_WRITE);
 	u8 host_stat, dmactl;
 
 	/* load PRD table addr. */
@@ -2464,8 +2457,7 @@ inline unsigned int ata_host_intr (struct ata_port *ap,
 	unsigned int handled = 0;
 
 	switch (qc->tf.protocol) {
-	case ATA_PROT_DMA_READ:
-	case ATA_PROT_DMA_WRITE:
+	case ATA_PROT_DMA:
 		if (ap->flags & ATA_FLAG_MMIO) {
 			void *mmio = (void *) ap->ioaddr.bmdma_addr;
 			host_stat = readb(mmio + ATA_DMA_STATUS);

drivers/scsi/libata-scsi.c

@@ -102,7 +102,7 @@ void ata_to_sense_error(struct ata_queued_cmd *qc)
 	cmd->sense_buffer[7] = 14 - 8;	/* addnl. sense len. FIXME: correct? */
 
 	/* additional-sense-code[-qualifier] */
-	if ((qc->flags & ATA_QCFLAG_WRITE) == 0) {
+	if (cmd->sc_data_direction == SCSI_DATA_READ) {
 		cmd->sense_buffer[12] = 0x11; /* "unrecovered read error" */
 		cmd->sense_buffer[13] = 0x04;
 	} else {
@@ -179,17 +179,15 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd,
 	tf->hob_lbal = 0;
 	tf->hob_lbam = 0;
 	tf->hob_lbah = 0;
+	tf->protocol = qc->dev->xfer_protocol;
 
 	if (scsicmd[0] == READ_10 || scsicmd[0] == READ_6 ||
 	    scsicmd[0] == READ_16) {
 		tf->command = qc->dev->read_cmd;
-		tf->protocol = qc->dev->r_protocol;
-		qc->flags &= ~ATA_QCFLAG_WRITE;
 		VPRINTK("reading\n");
 	} else {
 		tf->command = qc->dev->write_cmd;
-		tf->protocol = qc->dev->w_protocol;
-		qc->flags |= ATA_QCFLAG_WRITE;
+		tf->flags |= ATA_TFLAG_WRITE;
 		VPRINTK("writing\n");
 	}
 
@@ -886,7 +884,7 @@ static void atapi_scsi_queuecmd(struct ata_port *ap, struct ata_device *dev,
 
 	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
 	if (cmd->sc_data_direction == SCSI_DATA_WRITE) {
-		qc->flags |= ATA_QCFLAG_WRITE;
+		qc->tf.flags |= ATA_TFLAG_WRITE;
 		DPRINTK("direction: write\n");
 	}
 

drivers/scsi/sata_promise.c

@@ -393,12 +393,11 @@ static inline unsigned int pdc_pkt_header(struct ata_taskfile *tf,
 	 * and seq id (byte 2)
 	 */
 	switch (tf->protocol) {
-	case ATA_PROT_DMA_READ:
-		buf32[0] = cpu_to_le32(PDC_PKT_READ);
-		break;
-
-	case ATA_PROT_DMA_WRITE:
-		buf32[0] = 0;
+	case ATA_PROT_DMA:
+		if (!(tf->flags & ATA_TFLAG_WRITE))
+			buf32[0] = cpu_to_le32(PDC_PKT_READ);
+		else
+			buf32[0] = 0;
 		break;
 
 	case ATA_PROT_NODATA:
@@ -557,7 +556,7 @@ static inline unsigned int pdc20621_ata_pkt(struct ata_taskfile *tf,
 	/*
 	 * Set up ATA packet
 	 */
-	if (tf->protocol == ATA_PROT_DMA_READ)
+	if ((tf->protocol == ATA_PROT_DMA) && (!(tf->flags & ATA_TFLAG_WRITE)))
 		buf[i++] = PDC_PKT_READ;
 	else if (tf->protocol == ATA_PROT_NODATA)
 		buf[i++] = PDC_PKT_NODATA;
@@ -609,7 +608,7 @@ static inline void pdc20621_host_pkt(struct ata_taskfile *tf, u8 *buf,
 	/*
 	 * Set up Host DMA packet
 	 */
-	if (tf->protocol == ATA_PROT_DMA_READ)
+	if ((tf->protocol == ATA_PROT_DMA) && (!(tf->flags & ATA_TFLAG_WRITE)))
 		tmp = PDC_PKT_READ;
 	else
 		tmp = 0;
@@ -771,7 +770,7 @@ static void pdc20621_dma_start(struct ata_queued_cmd *qc)
 	struct ata_host_set *host_set = ap->host_set;
 	unsigned int port_no = ap->port_no;
 	void *mmio = host_set->mmio_base;
-	unsigned int rw = (qc->flags & ATA_QCFLAG_WRITE);
+	unsigned int rw = (qc->tf.flags & ATA_TFLAG_WRITE);
 	u8 seq = (u8) (port_no + 1);
 	unsigned int doing_hdma = 0, port_ofs;
 
@@ -824,8 +823,9 @@ static inline unsigned int pdc20621_host_intr( struct ata_port *ap,
 
 	VPRINTK("ENTER\n");
 
-	switch (qc->tf.protocol) {
-	case ATA_PROT_DMA_READ:
+	if ((qc->tf.protocol == ATA_PROT_DMA) &&	/* read */
+	    (!(qc->tf.flags & ATA_TFLAG_WRITE))) {
+
 		/* step two - DMA from DIMM to host */
 		if (doing_hdma) {
 			VPRINTK("ata%u: read hdma, 0x%x 0x%x\n", ap->id,
@@ -846,9 +846,9 @@ static inline unsigned int pdc20621_host_intr( struct ata_port *ap,
 					   port_ofs + PDC_DIMM_HOST_PKT);
 		}
 		handled = 1;
-		break;
 
-	case ATA_PROT_DMA_WRITE:
+	} else if (qc->tf.protocol == ATA_PROT_DMA) {	/* write */
+
 		/* step one - DMA from host to DIMM */
 		if (doing_hdma) {
 			u8 seq = (u8) (port_no + 1);
@@ -871,21 +871,20 @@ static inline unsigned int pdc20621_host_intr( struct ata_port *ap,
 			pdc20621_pop_hdma(qc);
 		}
 		handled = 1;
-		break;
 
-	case ATA_PROT_NODATA:   /* command completion, but no data xfer */
+	/* command completion, but no data xfer */
+	} else if (qc->tf.protocol == ATA_PROT_NODATA) {
+
 		status = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 1000);
 		DPRINTK("BUS_NODATA (drv_stat 0x%X)\n", status);
 		ata_qc_complete(qc, status, 0);
 		handled = 1;
-		break;
 
-        default:
-                ap->stats.idle_irq++;
-                break;
-        }
+	} else {
+		ap->stats.idle_irq++;
+	}
 
-        return handled;
+	return handled;
 }
 
 static irqreturn_t pdc20621_interrupt (int irq, void *dev_instance, struct pt_regs *regs)
@@ -1002,8 +1001,7 @@ static void pdc_eng_timeout(struct ata_port *ap)
 	qc->scsidone = scsi_finish_command;
 
 	switch (qc->tf.protocol) {
-	case ATA_PROT_DMA_READ:
-	case ATA_PROT_DMA_WRITE:
+	case ATA_PROT_DMA:
 		printk(KERN_ERR "ata%u: DMA timeout\n", ap->id);
 		ata_qc_complete(ata_qc_from_tag(ap, ap->active_tag),
 			        ata_wait_idle(ap) | ATA_ERR, 0);
@@ -1039,8 +1037,7 @@ static inline unsigned int pdc_host_intr( struct ata_port *ap,
 	unsigned int handled = 0;
 
 	switch (qc->tf.protocol) {
-	case ATA_PROT_DMA_READ:
-	case ATA_PROT_DMA_WRITE:
+	case ATA_PROT_DMA:
 		pdc_dma_complete(ap, qc);
 		handled = 1;
 		break;
@@ -1133,16 +1130,14 @@ static void pdc_dma_start(struct ata_queued_cmd *qc)
 
 static void pdc_tf_load_mmio(struct ata_port *ap, struct ata_taskfile *tf)
 {
-	if ((tf->protocol != ATA_PROT_DMA_READ) &&
-	    (tf->protocol != ATA_PROT_DMA_WRITE))
+	if (tf->protocol != ATA_PROT_DMA)
 		ata_tf_load_mmio(ap, tf);
 }
 
 
 static void pdc_exec_command_mmio(struct ata_port *ap, struct ata_taskfile *tf)
 {
-	if ((tf->protocol != ATA_PROT_DMA_READ) &&
-	    (tf->protocol != ATA_PROT_DMA_WRITE))
+	if (tf->protocol != ATA_PROT_DMA)
 		ata_exec_command_mmio(ap, tf);
 }
 

include/linux/ata.h

@@ -105,10 +105,8 @@ enum {
 	/* ATA taskfile protocols */
 	ATA_PROT_UNKNOWN	= 0,
 	ATA_PROT_NODATA		= 1,
-	ATA_PROT_PIO_READ	= 2,
-	ATA_PROT_PIO_WRITE	= 3,
-	ATA_PROT_DMA_READ	= 4,
-	ATA_PROT_DMA_WRITE	= 5,
+	ATA_PROT_PIO		= 2,
+	ATA_PROT_DMA		= 4,
 	ATA_PROT_ATAPI		= 6,
 	ATA_PROT_ATAPI_DMA	= 7,
 

include/linux/libata.h

@@ -108,11 +108,11 @@ enum {
 	ATA_FLAG_SATA_RESET	= (1 << 7), /* use COMRESET */
 
 	/* struct ata_taskfile flags */
-	ATA_TFLAG_LBA48		= (1 << 0),
+	ATA_TFLAG_LBA48		= (1 << 0), /* enable 48-bit LBA and "HOB" */
 	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_QCFLAG_WRITE	= (1 << 0), /* read==0, write==1 */
 	ATA_QCFLAG_ACTIVE	= (1 << 1), /* cmd not yet ack'd to scsi lyer */
 	ATA_QCFLAG_DMA		= (1 << 2), /* data delivered via DMA */
 	ATA_QCFLAG_ATAPI	= (1 << 3), /* is ATAPI packet command? */
@@ -295,8 +295,7 @@ struct ata_device {
 						 */
 
 	/* cache info about current transfer mode */
-	u8			r_protocol;	/* taskfile read protocol */
-	u8			w_protocol;	/* taskfile write protocol */
+	u8			xfer_protocol;	/* taskfile xfer protocol */
 	u8			read_cmd;	/* opcode to use on read */
 	u8			write_cmd;	/* opcode to use on write */
 };