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_promise.c b/drivers/ata/sata_promise.c
index 030665b..750d8cd 100644
--- a/drivers/ata/sata_promise.c
+++ b/drivers/ata/sata_promise.c
@@ -137,8 +137,8 @@
 	dma_addr_t		pkt_dma;
 };
 
-static int pdc_sata_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
-static int pdc_sata_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
+static int pdc_sata_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
+static int pdc_sata_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
 static int pdc_ata_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
 static int pdc_common_port_start(struct ata_port *ap);
 static int pdc_sata_port_start(struct ata_port *ap);
@@ -386,19 +386,21 @@
 	return ATA_CBL_SATA;
 }
 
-static int pdc_sata_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val)
+static int pdc_sata_scr_read(struct ata_link *link,
+			     unsigned int sc_reg, u32 *val)
 {
 	if (sc_reg > SCR_CONTROL)
 		return -EINVAL;
-	*val = readl(ap->ioaddr.scr_addr + (sc_reg * 4));
+	*val = readl(link->ap->ioaddr.scr_addr + (sc_reg * 4));
 	return 0;
 }
 
-static int pdc_sata_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val)
+static int pdc_sata_scr_write(struct ata_link *link,
+			      unsigned int sc_reg, u32 val)
 {
 	if (sc_reg > SCR_CONTROL)
 		return -EINVAL;
-	writel(val, ap->ioaddr.scr_addr + (sc_reg * 4));
+	writel(val, link->ap->ioaddr.scr_addr + (sc_reg * 4));
 	return 0;
 }
 
@@ -731,7 +733,7 @@
 	if (sata_scr_valid(&ap->link)) {
 		u32 serror;
 
-		pdc_sata_scr_read(ap, SCR_ERROR, &serror);
+		pdc_sata_scr_read(&ap->link, SCR_ERROR, &serror);
 		ehi->serror |= serror;
 	}