ahci: Check and set 64-bit DMA mask for platform AHCI driver

The current platform AHCI driver does not set the dma_mask correctly
for 64-bit DMA capable AHCI controller. This patch checks the AHCI
capability bit and set the dma_mask and coherent_dma_mask accordingly.
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Suman Tripathi <stripathi@apm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/libahci_platform.c

@@ -364,6 +364,19 @@ int ahci_platform_init_host(struct platform_device *pdev,
 			ap->ops = &ata_dummy_port_ops;
 	}
 
+	if (hpriv->cap & HOST_CAP_64) {
+		rc = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64));
+		if (rc) {
+			rc = dma_coerce_mask_and_coherent(dev,
+							  DMA_BIT_MASK(32));
+			if (rc) {
+				dev_err(dev, "Failed to enable 64-bit DMA.\n");
+				return rc;
+			}
+			dev_warn(dev, "Enable 32-bit DMA instead of 64-bit.\n");
+		}
+	}
+
 	rc = ahci_reset_controller(host);
 	if (rc)
 		return rc;