libata: Add H2D FIS "auxiliary" port flag

Add a new port flag, ATA_FLAG_FPDMA_AUX, used to indicate
support for transmission of the H2D FIS 'auxiliary' field.
Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/ahci.c

@@ -1288,6 +1288,14 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		 */
 		if (!(hpriv->flags & AHCI_HFLAG_NO_FPDMA_AA))
 			pi.flags |= ATA_FLAG_FPDMA_AA;
+
+		/*
+		 * All AHCI controllers should be forward-compatible
+		 * with the new auxiliary field. This code should be
+		 * conditionalized if any buggy AHCI controllers are
+		 * encountered.
+		 */
+		pi.flags |= ATA_FLAG_FPDMA_AUX;
 	}
 
 	if (hpriv->cap & HOST_CAP_PMP)

include/linux/libata.h

@@ -223,6 +223,7 @@ enum {
 	ATA_FLAG_ACPI_SATA	= (1 << 17), /* need native SATA ACPI layout */
 	ATA_FLAG_AN		= (1 << 18), /* controller supports AN */
 	ATA_FLAG_PMP		= (1 << 19), /* controller supports PMP */
+	ATA_FLAG_FPDMA_AUX	= (1 << 20), /* controller supports H2DFIS aux field */
 	ATA_FLAG_EM		= (1 << 21), /* driver supports enclosure
 					      * management */
 	ATA_FLAG_SW_ACTIVITY	= (1 << 22), /* driver supports sw activity