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, 16 insertions, 9 deletions

diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 2a86dc4598d0..db6763758952 100644
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -115,8 +115,8 @@ static int sil_init_one (struct pci_dev *pdev, const struct pci_device_id *ent);
 static int sil_pci_device_resume(struct pci_dev *pdev);
 #endif
 static void sil_dev_config(struct ata_device *dev);
-static u32 sil_scr_read (struct ata_port *ap, unsigned int sc_reg);
-static void sil_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val);
+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_set_mode (struct ata_port *ap, struct ata_device **r_failed);
 static void sil_freeze(struct ata_port *ap);
 static void sil_thaw(struct ata_port *ap);
@@ -350,19 +350,26 @@ static inline void __iomem *sil_scr_addr(struct ata_port *ap, unsigned int sc_re
         return NULL;
 }
 
-static u32 sil_scr_read (struct ata_port *ap, unsigned int sc_reg)
+static int sil_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val)
 {
         void __iomem *mmio = sil_scr_addr(ap, sc_reg);
-        if (mmio)
-                return readl(mmio);
-        return 0xffffffffU;
+
+        if (mmio) {
+                *val = readl(mmio);
+                return 0;
+        }
+        return -EINVAL;
 }
 
-static void sil_scr_write (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)
 {
         void __iomem *mmio = sil_scr_addr(ap, sc_reg);
-        if (mmio)
+
+        if (mmio) {
                 writel(val, mmio);
+                return 0;
+        }
+        return -EINVAL;
 }
 
 static void sil_host_intr(struct ata_port *ap, u32 bmdma2)
@@ -378,7 +385,7 @@ static void sil_host_intr(struct ata_port *ap, u32 bmdma2)
                  * controllers continue to assert IRQ as long as
                  * SError bits are pending.  Clear SError immediately.
                  */
-                serror = sil_scr_read(ap, SCR_ERROR);
+                sil_scr_read(ap, SCR_ERROR, &serror);
                 sil_scr_write(ap, SCR_ERROR, serror);
 
                 /* Trigger hotplug and accumulate SError only if the