pata_scc.c: small fixes (Workaround for errata A308)

This patch fixes some issues of the previous patch:
- Use mode_filter() hook to limit ATAPI UDMA mode
- "data loss" warning message
- handling of udma_mask

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/pata_scc.c

@@ -238,12 +238,6 @@ static void scc_set_dmamode (struct ata_port *ap, struct ata_device *adev)
 	else
 		offset = 0;	/* 100MHz */
 
-	/* errata A308 workaround: limit ATAPI UDMA mode to UDMA4 */
-	if (adev->class == ATA_DEV_ATAPI && speed > XFER_UDMA_4) {
-		printk(KERN_INFO "%s: limit ATAPI UDMA to UDMA4\n", DRV_NAME);
-		speed = XFER_UDMA_4;
-	}
-
 	if (speed >= XFER_UDMA_0)
 		idx = speed - XFER_UDMA_0;
 	else
@@ -264,6 +258,17 @@ static void scc_set_dmamode (struct ata_port *ap, struct ata_device *adev)
 		 JCTSStbl[offset][idx] << 16 | JCENVTtbl[offset][idx]);
 }
 
+unsigned long scc_mode_filter(struct ata_device *adev, unsigned long mask)
+{
+	/* errata A308 workaround: limit ATAPI UDMA mode to UDMA4 */
+	if (adev->class == ATA_DEV_ATAPI &&
+	    (mask & (0xE0 << ATA_SHIFT_UDMA))) {
+		printk(KERN_INFO "%s: limit ATAPI UDMA to UDMA4\n", DRV_NAME);
+		mask &= ~(0xE0 << ATA_SHIFT_UDMA);
+	}
+	return ata_pci_default_filter(adev, mask);
+}
+
 /**
  *	scc_tf_load - send taskfile registers to host controller
  *	@ap: Port to which output is sent
@@ -741,7 +746,7 @@ static u8 scc_bmdma_status (struct ata_port *ap)
 		return host_stat;
 
 	/* errata A252,A308 workaround: Step4 */
-	if (ata_altstatus(ap) & ATA_ERR && int_status & INTSTS_INTRQ)
+	if ((ata_altstatus(ap) & ATA_ERR) && (int_status & INTSTS_INTRQ))
 		return (host_stat | ATA_DMA_INTR);
 
 	/* errata A308 workaround Step5 */
@@ -752,11 +757,11 @@ static u8 scc_bmdma_status (struct ata_port *ap)
 		if ((qc->tf.protocol == ATA_PROT_DMA &&
 		     qc->dev->xfer_mode > XFER_UDMA_4)) {
 			if (!(int_status & INTSTS_ACTEINT)) {
-				printk(KERN_WARNING "ata%u: data lost occurred. (ACTEINT==0, retry:%d)\n",
-				       ap->print_id, retry);
+				printk(KERN_WARNING "ata%u: operation failed (transfer data loss)\n",
+				       ap->print_id);
 				host_stat |= ATA_DMA_ERR;
 				if (retry++)
-					ap->udma_mask >>= 1;
+					ap->udma_mask &= ~(1 << qc->dev->xfer_mode);
 			} else
 				retry = 0;
 		}
@@ -1016,7 +1021,7 @@ static const struct ata_port_operations scc_pata_ops = {
 	.port_disable		= ata_port_disable,
 	.set_piomode		= scc_set_piomode,
 	.set_dmamode		= scc_set_dmamode,
-	.mode_filter		= ata_pci_default_filter,
+	.mode_filter		= scc_mode_filter,
 
 	.tf_load		= scc_tf_load,
 	.tf_read		= scc_tf_read,