libata: make SCR access ops per-link

Logically, SCR access ops should take @link; however, there was no
compelling reason to convert all SCR access ops when adding @link
abstraction as there's one-to-one mapping between a port and a non-PMP
link.  However, that assumption won't hold anymore with the scheduled
addition of slave link.

Make SCR access ops per-link.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 88bf421..031d7b7 100644
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -115,8 +115,8 @@
 static int sil_pci_device_resume(struct pci_dev *pdev);
 #endif
 static void sil_dev_config(struct ata_device *dev);
-static int sil_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
-static int sil_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
+static int sil_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
+static int sil_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
 static int sil_set_mode(struct ata_link *link, struct ata_device **r_failed);
 static void sil_freeze(struct ata_port *ap);
 static void sil_thaw(struct ata_port *ap);
@@ -317,9 +317,9 @@
 	return NULL;
 }
 
-static int sil_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val)
+static int sil_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val)
 {
-	void __iomem *mmio = sil_scr_addr(ap, sc_reg);
+	void __iomem *mmio = sil_scr_addr(link->ap, sc_reg);
 
 	if (mmio) {
 		*val = readl(mmio);
@@ -328,9 +328,9 @@
 	return -EINVAL;
 }
 
-static int sil_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val)
+static int sil_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
 {
-	void __iomem *mmio = sil_scr_addr(ap, sc_reg);
+	void __iomem *mmio = sil_scr_addr(link->ap, sc_reg);
 
 	if (mmio) {
 		writel(val, mmio);
@@ -352,8 +352,8 @@
 		 * controllers continue to assert IRQ as long as
 		 * SError bits are pending.  Clear SError immediately.
 		 */
-		sil_scr_read(ap, SCR_ERROR, &serror);
-		sil_scr_write(ap, SCR_ERROR, serror);
+		sil_scr_read(&ap->link, SCR_ERROR, &serror);
+		sil_scr_write(&ap->link, SCR_ERROR, serror);
 
 		/* Sometimes spurious interrupts occur, double check
 		 * it's PHYRDY CHG.