libata: make ->scr_read/write callbacks return error code

Convert ->scr_read/write callbacks to return error code to better
indicate failure.  This will help handling of SCR_NOTIFICATION.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/ata/sata_via.c b/drivers/ata/sata_via.c
index c4124475f754..86b7bfc17324 100644
--- a/drivers/ata/sata_via.c
+++ b/drivers/ata/sata_via.c
@@ -72,8 +72,8 @@ enum {
 };
 
 static int svia_init_one (struct pci_dev *pdev, const struct pci_device_id *ent);
-static u32 svia_scr_read (struct ata_port *ap, unsigned int sc_reg);
-static void svia_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val);
+static int svia_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
+static int svia_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
 static void svia_noop_freeze(struct ata_port *ap);
 static void vt6420_error_handler(struct ata_port *ap);
 static int vt6421_pata_cable_detect(struct ata_port *ap);
@@ -249,18 +249,20 @@ MODULE_LICENSE("GPL");
 MODULE_DEVICE_TABLE(pci, svia_pci_tbl);
 MODULE_VERSION(DRV_VERSION);
 
-static u32 svia_scr_read (struct ata_port *ap, unsigned int sc_reg)
+static int svia_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val)
 {
         if (sc_reg > SCR_CONTROL)
-                return 0xffffffffU;
-        return ioread32(ap->ioaddr.scr_addr + (4 * sc_reg));
+                return -EINVAL;
+        *val = ioread32(ap->ioaddr.scr_addr + (4 * sc_reg));
+        return 0;
 }
 
-static void svia_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val)
+static int svia_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val)
 {
         if (sc_reg > SCR_CONTROL)
-                return;
+                return -EINVAL;
         iowrite32(val, ap->ioaddr.scr_addr + (4 * sc_reg));
+        return 0;
 }
 
 static void svia_noop_freeze(struct ata_port *ap)
@@ -305,18 +307,19 @@ static int vt6420_prereset(struct ata_port *ap, unsigned long deadline)
 
         /* Resume phy.  This is the old SATA resume sequence */
         svia_scr_write(ap, SCR_CONTROL, 0x300);
-        svia_scr_read(ap, SCR_CONTROL); /* flush */
+        svia_scr_read(ap, SCR_CONTROL, &scontrol); /* flush */
 
         /* wait for phy to become ready, if necessary */
         do {
                 msleep(200);
-                if ((svia_scr_read(ap, SCR_STATUS) & 0xf) != 1)
+                svia_scr_read(ap, SCR_STATUS, &sstatus);
+                if ((sstatus & 0xf) != 1)
                         break;
         } while (time_before(jiffies, timeout));
 
         /* open code sata_print_link_status() */
-        sstatus = svia_scr_read(ap, SCR_STATUS);
-        scontrol = svia_scr_read(ap, SCR_CONTROL);
+        svia_scr_read(ap, SCR_STATUS, &sstatus);
+        svia_scr_read(ap, SCR_CONTROL, &scontrol);
 
         online = (sstatus & 0xf) == 0x3;
 
@@ -325,7 +328,7 @@ static int vt6420_prereset(struct ata_port *ap, unsigned long deadline)
                         online ? "up" : "down", sstatus, scontrol);
 
         /* SStatus is read one more time */
-        svia_scr_read(ap, SCR_STATUS);
+        svia_scr_read(ap, SCR_STATUS, &sstatus);
 
         if (!online) {
                 /* tell EH to bail */