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, 13 insertions, 10 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 210292cd8ad1..e044d6477a0f 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -216,8 +216,8 @@ struct ahci_port_priv {
         unsigned int            ncq_saw_sdb:1;
 };
 
-static u32 ahci_scr_read (struct ata_port *ap, unsigned int sc_reg);
-static void ahci_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val);
+static int ahci_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
+static int ahci_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
 static int ahci_init_one (struct pci_dev *pdev, const struct pci_device_id *ent);
 static unsigned int ahci_qc_issue(struct ata_queued_cmd *qc);
 static void ahci_irq_clear(struct ata_port *ap);
@@ -625,7 +625,7 @@ static void ahci_restore_initial_config(struct ata_host *host)
         (void) readl(mmio + HOST_PORTS_IMPL);   /* flush */
 }
 
-static u32 ahci_scr_read (struct ata_port *ap, unsigned int sc_reg_in)
+static int ahci_scr_read(struct ata_port *ap, unsigned int sc_reg_in, u32 *val)
 {
         unsigned int sc_reg;
 
@@ -635,15 +635,15 @@ static u32 ahci_scr_read (struct ata_port *ap, unsigned int sc_reg_in)
         case SCR_ERROR:         sc_reg = 2; break;
         case SCR_ACTIVE:        sc_reg = 3; break;
         default:
-                return 0xffffffffU;
+                return -EINVAL;
         }
 
-        return readl(ap->ioaddr.scr_addr + (sc_reg * 4));
+        *val = readl(ap->ioaddr.scr_addr + (sc_reg * 4));
+        return 0;
 }
 
 
-static void ahci_scr_write (struct ata_port *ap, unsigned int sc_reg_in,
-                               u32 val)
+static int ahci_scr_write(struct ata_port *ap, unsigned int sc_reg_in, u32 val)
 {
         unsigned int sc_reg;
 
@@ -653,10 +653,11 @@ static void ahci_scr_write (struct ata_port *ap, unsigned int sc_reg_in,
         case SCR_ERROR:         sc_reg = 2; break;
         case SCR_ACTIVE:        sc_reg = 3; break;
         default:
-                return;
+                return -EINVAL;
         }
 
         writel(val, ap->ioaddr.scr_addr + (sc_reg * 4));
+        return 0;
 }
 
 static void ahci_start_engine(struct ata_port *ap)
@@ -1133,6 +1134,7 @@ static int ahci_hardreset(struct ata_port *ap, unsigned int *class,
 static int ahci_vt8251_hardreset(struct ata_port *ap, unsigned int *class,
                                  unsigned long deadline)
 {
+        u32 serror;
         int rc;
 
         DPRINTK("ENTER\n");
@@ -1143,7 +1145,8 @@ static int ahci_vt8251_hardreset(struct ata_port *ap, unsigned int *class,
                                  deadline);
 
         /* vt8251 needs SError cleared for the port to operate */
-        ahci_scr_write(ap, SCR_ERROR, ahci_scr_read(ap, SCR_ERROR));
+        ahci_scr_read(ap, SCR_ERROR, &serror);
+        ahci_scr_write(ap, SCR_ERROR, serror);
 
         ahci_start_engine(ap);
 
@@ -1265,7 +1268,7 @@ static void ahci_error_intr(struct ata_port *ap, u32 irq_stat)
         ata_ehi_clear_desc(ehi);
 
         /* AHCI needs SError cleared; otherwise, it might lock up */
-        serror = ahci_scr_read(ap, SCR_ERROR);
+        ahci_scr_read(ap, SCR_ERROR, &serror);
         ahci_scr_write(ap, SCR_ERROR, serror);
 
         /* analyze @irq_stat */