diff --git a/drivers/ata/sata_sx4.c b/drivers/ata/sata_sx4.c
index 1ce98af..eb05a3c 100644
--- a/drivers/ata/sata_sx4.c
+++ b/drivers/ata/sata_sx4.c
@@ -687,8 +687,11 @@
 static unsigned int pdc20621_qc_issue(struct ata_queued_cmd *qc)
 {
 	switch (qc->tf.protocol) {
-	case ATA_PROT_DMA:
 	case ATA_PROT_NODATA:
+		if (qc->tf.flags & ATA_TFLAG_POLLING)
+			break;
+		/*FALLTHROUGH*/
+	case ATA_PROT_DMA:
 		pdc20621_packet_start(qc);
 		return 0;
 
@@ -787,12 +790,7 @@
 
 static void pdc20621_irq_clear(struct ata_port *ap)
 {
-	struct ata_host *host = ap->host;
-	void __iomem *mmio = host->iomap[PDC_MMIO_BAR];
-
-	mmio += PDC_CHIP0_OFS;
-
-	readl(mmio + PDC_20621_SEQMASK);
+	ioread8(ap->ioaddr.status_addr);
 }
 
 static irqreturn_t pdc20621_interrupt(int irq, void *dev_instance)
@@ -877,14 +875,12 @@
 static void pdc_thaw(struct ata_port *ap)
 {
 	void __iomem *mmio = ap->ioaddr.cmd_addr;
-	void __iomem *mmio_base;
 	u32 tmp;
 
 	/* FIXME: start HDMA engine, if zero ATA engines running */
 
-	/* reading SEQ mask register clears IRQ */
-	mmio_base = ap->host->iomap[PDC_MMIO_BAR] + PDC_CHIP0_OFS;
-	readl(mmio_base + PDC_20621_SEQMASK);
+	/* clear IRQ */
+	ioread8(ap->ioaddr.status_addr);
 
 	/* turn IRQ back on */
 	tmp = readl(mmio + PDC_CTLSTAT);
@@ -974,7 +970,7 @@
 static void pdc_tf_load_mmio(struct ata_port *ap, const struct ata_taskfile *tf)
 {
 	WARN_ON(tf->protocol == ATA_PROT_DMA ||
-		tf->protocol == ATA_PROT_NODATA);
+		tf->protocol == ATAPI_PROT_DMA);
 	ata_sff_tf_load(ap, tf);
 }
 
@@ -982,7 +978,7 @@
 static void pdc_exec_command_mmio(struct ata_port *ap, const struct ata_taskfile *tf)
 {
 	WARN_ON(tf->protocol == ATA_PROT_DMA ||
-		tf->protocol == ATA_PROT_NODATA);
+		tf->protocol == ATAPI_PROT_DMA);
 	ata_sff_exec_command(ap, tf);
 }