libata: backport ATA_FLAG_NO_SRST and ATA_FLAG_ASSUME_ATA

Differs from mainline, but the functionality is already there.

Backport ATA_FLAG_NO_SRST and ATA_FLAG_ASSUME_ATA.  These are
originally link flags (ATA_LFLAG_*) but link abstraction doesn't exist
on 2.6.23, so make it port flags.

This is for the following workaround for ASUS P5W DH Deluxe.

These new flags don't introduce any behavior change unless set and
nobody sets them yet.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/ata/libata-eh.c

@@ -1759,9 +1759,11 @@ static int ata_do_reset(struct ata_port *ap, ata_reset_fn_t reset,
 	return 0;
 }
 
-static int ata_eh_followup_srst_needed(int rc, int classify,
-				       const unsigned int *classes)
+static int ata_eh_followup_srst_needed(struct ata_port *ap, int rc,
+				int classify, const unsigned int *classes)
 {
+	if (ap->flags & ATA_FLAG_NO_SRST)
+		return 0;
 	if (rc == -EAGAIN)
 		return 1;
 	if (rc != 0)
@@ -1792,7 +1794,8 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
 	 */
 	action = ehc->i.action;
 	ehc->i.action &= ~ATA_EH_RESET_MASK;
-	if (softreset && (!hardreset || (!sata_set_spd_needed(ap) &&
+	if (softreset && (!hardreset || (!(ap->flags & ATA_FLAG_NO_SRST) &&
+					 !sata_set_spd_needed(ap) &&
 					 !(action & ATA_EH_HARDRESET))))
 		ehc->i.action |= ATA_EH_SOFTRESET;
 	else
@@ -1855,7 +1858,7 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
 	rc = ata_do_reset(ap, reset, classes, deadline);
 
 	if (reset == hardreset &&
-	    ata_eh_followup_srst_needed(rc, classify, classes)) {
+	    ata_eh_followup_srst_needed(ap, rc, classify, classes)) {
 		/* okay, let's do follow-up softreset */
 		reset = softreset;
 
@@ -1870,8 +1873,8 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
 		ata_eh_about_to_do(ap, NULL, ATA_EH_RESET_MASK);
 		rc = ata_do_reset(ap, reset, classes, deadline);
 
-		if (rc == 0 && classify &&
-		    classes[0] == ATA_DEV_UNKNOWN) {
+		if (rc == 0 && classify && classes[0] == ATA_DEV_UNKNOWN &&
+		    !(ap->flags & ATA_FLAG_ASSUME_ATA)) {
 			ata_port_printk(ap, KERN_ERR,
 					"classification failed\n");
 			rc = -EINVAL;
@@ -1879,6 +1882,10 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
 		}
 	}
 
+	/* if we skipped follow-up srst, clear rc */
+	if (rc == -EAGAIN)
+		rc = 0;
+
 	if (rc && try < ARRAY_SIZE(ata_eh_reset_timeouts)) {
 		unsigned long now = jiffies;
 
@@ -1906,8 +1913,17 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
 		/* After the reset, the device state is PIO 0 and the
 		 * controller state is undefined.  Record the mode.
 		 */
-		for (i = 0; i < ATA_MAX_DEVICES; i++)
-			ap->device[i].pio_mode = XFER_PIO_0;
+		for (i = 0; i < ata_port_max_devices(ap); i++) {
+			struct ata_device *dev = &ap->device[i];
+
+			dev->pio_mode = XFER_PIO_0;
+
+			if (ata_port_offline(ap))
+				continue;
+
+			if (ap->flags & ATA_FLAG_ASSUME_ATA)
+				classes[dev->devno] = ATA_DEV_ATA;
+		}
 
 		/* record current link speed */
 		if (sata_scr_read(ap, SCR_STATUS, &sstatus) == 0)

include/linux/libata.h

@@ -177,6 +177,8 @@ enum {
 	ATA_FLAG_IGN_SIMPLEX	= (1 << 15), /* ignore SIMPLEX */
 	ATA_FLAG_NO_IORDY	= (1 << 16), /* controller lacks iordy */
 	ATA_FLAG_ACPI_SATA	= (1 << 17), /* need native SATA ACPI layout */
+	ATA_FLAG_NO_SRST	= (1 << 18),
+	ATA_FLAG_ASSUME_ATA	= (1 << 19),
 
 	/* The following flag belongs to ap->pflags but is kept in
 	 * ap->flags because it's referenced in many LLDs and will be