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, 9 insertions, 7 deletions

diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
index 5d943da042f7..0b58c4df6fd2 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -236,8 +236,8 @@ static void nv_ck804_host_stop(struct ata_host *host);
 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 u32 nv_scr_read (struct ata_port *ap, unsigned int sc_reg);
-static void nv_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val);
+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 void nv_nf2_freeze(struct ata_port *ap);
 static void nv_nf2_thaw(struct ata_port *ap);
@@ -1393,20 +1393,22 @@ static irqreturn_t nv_ck804_interrupt(int irq, void *dev_instance)
         return ret;
 }
 
-static u32 nv_scr_read (struct ata_port *ap, unsigned int sc_reg)
+static int nv_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val)
 {
         if (sc_reg > SCR_CONTROL)
-                return 0xffffffffU;
+                return -EINVAL;
 
-        return ioread32(ap->ioaddr.scr_addr + (sc_reg * 4));
+        *val = ioread32(ap->ioaddr.scr_addr + (sc_reg * 4));
+        return 0;
 }
 
-static void nv_scr_write (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)
 {
         if (sc_reg > SCR_CONTROL)
-                return;
+                return -EINVAL;
 
         iowrite32(val, ap->ioaddr.scr_addr + (sc_reg * 4));
+        return 0;
 }
 
 static void nv_nf2_freeze(struct ata_port *ap)