[PATCH] sata_sil24: implement NCQ support

Implement NCQ support.  Sil24 has 31 command slots and all of them are
used for NCQ command queueing.  libata guarantees that no other
command is in progress when it issues an internal command, so always
use tag 0 for internal commands.

Signed-off-by: Tejun Heo <htejun@gmail.com>

drivers/scsi/sata_sil24.c

@@ -216,6 +216,8 @@ enum {
 	SGE_DRD			= (1 << 29), /* discard data read (/dev/null)
 						data address ignored */
 
+	SIL24_MAX_CMDS		= 31,
+
 	/* board id */
 	BID_SIL3124		= 0,
 	BID_SIL3132		= 1,
@@ -223,7 +225,8 @@ enum {
 
 	/* host flags */
 	SIL24_COMMON_FLAGS	= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
-				  ATA_FLAG_MMIO | ATA_FLAG_PIO_DMA,
+				  ATA_FLAG_MMIO | ATA_FLAG_PIO_DMA |
+				  ATA_FLAG_NCQ,
 	SIL24_FLAG_PCIX_IRQ_WOC	= (1 << 24), /* IRQ loss errata on PCI-X */
 
 	IRQ_STAT_4PORTS		= 0xf,
@@ -355,7 +358,8 @@ static struct scsi_host_template sil24_sht = {
 	.name			= DRV_NAME,
 	.ioctl			= ata_scsi_ioctl,
 	.queuecommand		= ata_scsi_queuecmd,
-	.can_queue		= ATA_DEF_QUEUE,
+	.change_queue_depth	= ata_scsi_change_queue_depth,
+	.can_queue		= SIL24_MAX_CMDS,
 	.this_id		= ATA_SHT_THIS_ID,
 	.sg_tablesize		= LIBATA_MAX_PRD,
 	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,
@@ -437,6 +441,13 @@ static struct ata_port_info sil24_port_info[] = {
 	},
 };
 
+static int sil24_tag(int tag)
+{
+	if (unlikely(ata_tag_internal(tag)))
+		return 0;
+	return tag;
+}
+
 static void sil24_dev_config(struct ata_port *ap, struct ata_device *dev)
 {
 	void __iomem *port = (void __iomem *)ap->ioaddr.cmd_addr;
@@ -649,14 +660,17 @@ static void sil24_qc_prep(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
 	struct sil24_port_priv *pp = ap->private_data;
-	union sil24_cmd_block *cb = pp->cmd_block + qc->tag;
+	union sil24_cmd_block *cb;
 	struct sil24_prb *prb;
 	struct sil24_sge *sge;
 	u16 ctrl = 0;
 
+	cb = &pp->cmd_block[sil24_tag(qc->tag)];
+
 	switch (qc->tf.protocol) {
 	case ATA_PROT_PIO:
 	case ATA_PROT_DMA:
+	case ATA_PROT_NCQ:
 	case ATA_PROT_NODATA:
 		prb = &cb->ata.prb;
 		sge = cb->ata.sge;
@@ -694,12 +708,17 @@ static void sil24_qc_prep(struct ata_queued_cmd *qc)
 static unsigned int sil24_qc_issue(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
-	void __iomem *port = (void __iomem *)ap->ioaddr.cmd_addr;
 	struct sil24_port_priv *pp = ap->private_data;
-	dma_addr_t paddr = pp->cmd_block_dma + qc->tag * sizeof(*pp->cmd_block);
+	void __iomem *port = (void __iomem *)ap->ioaddr.cmd_addr;
+	unsigned int tag = sil24_tag(qc->tag);
+	dma_addr_t paddr;
+	void __iomem *activate;
 
-	writel((u32)paddr, port + PORT_CMD_ACTIVATE);
-	writel((u64)paddr >> 32, port + PORT_CMD_ACTIVATE + 4);
+	paddr = pp->cmd_block_dma + tag * sizeof(*pp->cmd_block);
+	activate = port + PORT_CMD_ACTIVATE + tag * 8;
+
+	writel((u32)paddr, activate);
+	writel((u64)paddr >> 32, activate + 4);
 
 	return 0;
 }
@@ -791,9 +810,6 @@ static void sil24_error_intr(struct ata_port *ap)
 		/* record error info */
 		qc = ata_qc_from_tag(ap, ap->active_tag);
 		if (qc) {
-			int tag = qc->tag;
-			if (unlikely(ata_tag_internal(tag)))
-				tag = 0;
 			sil24_update_tf(ap);
 			qc->err_mask |= err_mask;
 		} else
@@ -809,11 +825,17 @@ static void sil24_error_intr(struct ata_port *ap)
 		ata_port_abort(ap);
 }
 
+static void sil24_finish_qc(struct ata_queued_cmd *qc)
+{
+	if (qc->flags & ATA_QCFLAG_RESULT_TF)
+		sil24_update_tf(qc->ap);
+}
+
 static inline void sil24_host_intr(struct ata_port *ap)
 {
 	void __iomem *port = (void __iomem *)ap->ioaddr.cmd_addr;
-	struct ata_queued_cmd *qc;
-	u32 slot_stat;
+	u32 slot_stat, qc_active;
+	int rc;
 
 	slot_stat = readl(port + PORT_SLOT_STAT);
 
@@ -825,18 +847,22 @@ static inline void sil24_host_intr(struct ata_port *ap)
 	if (ap->flags & SIL24_FLAG_PCIX_IRQ_WOC)
 		writel(PORT_IRQ_COMPLETE, port + PORT_IRQ_STAT);
 
-	qc = ata_qc_from_tag(ap, ap->active_tag);
-	if (qc) {
-		if (qc->flags & ATA_QCFLAG_RESULT_TF)
-			sil24_update_tf(ap);
-		ata_qc_complete(qc);
+	qc_active = slot_stat & ~HOST_SSTAT_ATTN;
+	rc = ata_qc_complete_multiple(ap, qc_active, sil24_finish_qc);
+	if (rc > 0)
+		return;
+	if (rc < 0) {
+		struct ata_eh_info *ehi = &ap->eh_info;
+		ehi->err_mask |= AC_ERR_HSM;
+		ehi->action |= ATA_EH_SOFTRESET;
+		ata_port_freeze(ap);
 		return;
 	}
 
 	if (ata_ratelimit())
 		ata_port_printk(ap, KERN_INFO, "spurious interrupt "
-			"(slot_stat 0x%x active_tag %d)\n",
-			slot_stat, ap->active_tag);
+			"(slot_stat 0x%x active_tag %d sactive 0x%x)\n",
+			slot_stat, ap->active_tag, ap->sactive);
 }
 
 static irqreturn_t sil24_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
@@ -903,7 +929,7 @@ static void sil24_post_internal_cmd(struct ata_queued_cmd *qc)
 
 static inline void sil24_cblk_free(struct sil24_port_priv *pp, struct device *dev)
 {
-	const size_t cb_size = sizeof(*pp->cmd_block);
+	const size_t cb_size = sizeof(*pp->cmd_block) * SIL24_MAX_CMDS;
 
 	dma_free_coherent(dev, cb_size, pp->cmd_block, pp->cmd_block_dma);
 }
@@ -913,7 +939,7 @@ static int sil24_port_start(struct ata_port *ap)
 	struct device *dev = ap->host_set->dev;
 	struct sil24_port_priv *pp;
 	union sil24_cmd_block *cb;
-	size_t cb_size = sizeof(*cb);
+	size_t cb_size = sizeof(*cb) * SIL24_MAX_CMDS;
 	dma_addr_t cb_dma;
 	int rc = -ENOMEM;