libata-sff: ata_sff_irq_clear() is BMDMA specific

ata_sff_irq_clear() is BMDMA specific.  Rename it to
ata_bmdma_irq_clear(), move it to ata_bmdma_port_ops and make
->sff_irq_clear() optional.

Note: ata_bmdma_irq_clear() is actually only needed by ata_piix and
      possibly by sata_sil.  This should be moved to respective low
      level drivers later.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-sff.c

@@ -63,7 +63,6 @@ const struct ata_port_operations ata_sff_port_ops = {
 	.sff_tf_read		= ata_sff_tf_read,
 	.sff_exec_command	= ata_sff_exec_command,
 	.sff_data_xfer		= ata_sff_data_xfer,
-	.sff_irq_clear		= ata_sff_irq_clear,
 	.sff_drain_fifo		= ata_sff_drain_fifo,
 
 	.lost_interrupt		= ata_sff_lost_interrupt,
@@ -395,32 +394,11 @@ void ata_sff_irq_on(struct ata_port *ap)
 		ata_sff_set_devctl(ap, ap->ctl);
 	ata_wait_idle(ap);
 
-	ap->ops->sff_irq_clear(ap);
+	if (ap->ops->sff_irq_clear)
+		ap->ops->sff_irq_clear(ap);
 }
 EXPORT_SYMBOL_GPL(ata_sff_irq_on);
 
-/**
- *	ata_sff_irq_clear - Clear PCI IDE BMDMA interrupt.
- *	@ap: Port associated with this ATA transaction.
- *
- *	Clear interrupt and error flags in DMA status register.
- *
- *	May be used as the irq_clear() entry in ata_port_operations.
- *
- *	LOCKING:
- *	spin_lock_irqsave(host lock)
- */
-void ata_sff_irq_clear(struct ata_port *ap)
-{
-	void __iomem *mmio = ap->ioaddr.bmdma_addr;
-
-	if (!mmio)
-		return;
-
-	iowrite8(ioread8(mmio + ATA_DMA_STATUS), mmio + ATA_DMA_STATUS);
-}
-EXPORT_SYMBOL_GPL(ata_sff_irq_clear);
-
 /**
  *	ata_sff_tf_load - send taskfile registers to host controller
  *	@ap: Port to which output is sent
@@ -1572,7 +1550,8 @@ unsigned int ata_sff_host_intr(struct ata_port *ap,
 	}
 
 	/* clear irq events */
-	ap->ops->sff_irq_clear(ap);
+	if (ap->ops->sff_irq_clear)
+		ap->ops->sff_irq_clear(ap);
 
 	ata_sff_hsm_move(ap, qc, status, 0);
 
@@ -1588,7 +1567,8 @@ idle_irq:
 #ifdef ATA_IRQ_TRAP
 	if ((ap->stats.idle_irq % 1000) == 0) {
 		ap->ops->sff_check_status(ap);
-		ap->ops->sff_irq_clear(ap);
+		if (ap->ops->sff_irq_clear)
+			ap->ops->sff_irq_clear(ap);
 		ata_port_printk(ap, KERN_WARNING, "irq trap\n");
 		return 1;
 	}
@@ -1658,7 +1638,8 @@ retry:
 
 			if (idle & (1 << i)) {
 				ap->ops->sff_check_status(ap);
-				ap->ops->sff_irq_clear(ap);
+				if (ap->ops->sff_irq_clear)
+					ap->ops->sff_irq_clear(ap);
 			} else {
 				/* clear INTRQ and check if BUSY cleared */
 				if (!(ap->ops->sff_check_status(ap) & ATA_BUSY))
@@ -1744,7 +1725,8 @@ void ata_sff_freeze(struct ata_port *ap)
 	 */
 	ap->ops->sff_check_status(ap);
 
-	ap->ops->sff_irq_clear(ap);
+	if (ap->ops->sff_irq_clear)
+		ap->ops->sff_irq_clear(ap);
 }
 EXPORT_SYMBOL_GPL(ata_sff_freeze);
 
@@ -1761,7 +1743,8 @@ void ata_sff_thaw(struct ata_port *ap)
 {
 	/* clear & re-enable interrupts */
 	ap->ops->sff_check_status(ap);
-	ap->ops->sff_irq_clear(ap);
+	if (ap->ops->sff_irq_clear)
+		ap->ops->sff_irq_clear(ap);
 	ata_sff_irq_on(ap);
 }
 EXPORT_SYMBOL_GPL(ata_sff_thaw);
@@ -2580,6 +2563,7 @@ const struct ata_port_operations ata_bmdma_port_ops = {
 	.qc_prep		= ata_bmdma_qc_prep,
 	.qc_issue		= ata_bmdma_qc_issue,
 
+	.sff_irq_clear		= ata_bmdma_irq_clear,
 	.bmdma_setup		= ata_bmdma_setup,
 	.bmdma_start		= ata_bmdma_start,
 	.bmdma_stop		= ata_bmdma_stop,
@@ -2848,7 +2832,8 @@ void ata_bmdma_error_handler(struct ata_port *ap)
 		/* if we're gonna thaw, make sure IRQ is clear */
 		if (thaw) {
 			ap->ops->sff_check_status(ap);
-			ap->ops->sff_irq_clear(ap);
+			if (ap->ops->sff_irq_clear)
+				ap->ops->sff_irq_clear(ap);
 		}
 	}
 
@@ -2881,6 +2866,28 @@ void ata_bmdma_post_internal_cmd(struct ata_queued_cmd *qc)
 }
 EXPORT_SYMBOL_GPL(ata_bmdma_post_internal_cmd);
 
+/**
+ *	ata_bmdma_irq_clear - Clear PCI IDE BMDMA interrupt.
+ *	@ap: Port associated with this ATA transaction.
+ *
+ *	Clear interrupt and error flags in DMA status register.
+ *
+ *	May be used as the irq_clear() entry in ata_port_operations.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host lock)
+ */
+void ata_bmdma_irq_clear(struct ata_port *ap)
+{
+	void __iomem *mmio = ap->ioaddr.bmdma_addr;
+
+	if (!mmio)
+		return;
+
+	iowrite8(ioread8(mmio + ATA_DMA_STATUS), mmio + ATA_DMA_STATUS);
+}
+EXPORT_SYMBOL_GPL(ata_bmdma_irq_clear);
+
 /**
  *	ata_bmdma_setup - Set up PCI IDE BMDMA transaction
  *	@qc: Info associated with this ATA transaction.