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_nv.c b/drivers/ata/sata_nv.c
index 1e1f3f3..88fd4ae 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -302,8 +302,8 @@
 static irqreturn_t nv_generic_interrupt(int irq, void *dev_instance);
 static irqreturn_t nv_nf2_interrupt(int irq, void *dev_instance);
 static irqreturn_t nv_ck804_interrupt(int irq, void *dev_instance);
-static int nv_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
-static int nv_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
+static int nv_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
+static int nv_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
 
 static void nv_nf2_freeze(struct ata_port *ap);
 static void nv_nf2_thaw(struct ata_port *ap);
@@ -1492,21 +1492,21 @@
 	return ret;
 }
 
-static int nv_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val)
+static int nv_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val)
 {
 	if (sc_reg > SCR_CONTROL)
 		return -EINVAL;
 
-	*val = ioread32(ap->ioaddr.scr_addr + (sc_reg * 4));
+	*val = ioread32(link->ap->ioaddr.scr_addr + (sc_reg * 4));
 	return 0;
 }
 
-static int nv_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val)
+static int nv_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
 {
 	if (sc_reg > SCR_CONTROL)
 		return -EINVAL;
 
-	iowrite32(val, ap->ioaddr.scr_addr + (sc_reg * 4));
+	iowrite32(val, link->ap->ioaddr.scr_addr + (sc_reg * 4));
 	return 0;
 }
 
@@ -2184,9 +2184,9 @@
 	if (!pp->qc_active)
 		return;
 
-	if (ap->ops->scr_read(ap, SCR_ERROR, &serror))
+	if (ap->ops->scr_read(&ap->link, SCR_ERROR, &serror))
 		return;
-	ap->ops->scr_write(ap, SCR_ERROR, serror);
+	ap->ops->scr_write(&ap->link, SCR_ERROR, serror);
 
 	if (ata_stat & ATA_ERR) {
 		ata_ehi_clear_desc(ehi);