[PATCH] libata: new ->probe_reset operation

Add new ->probe_reset operation to ata_port_operations obsoleting
->phy_reset.  The main difference from ->phy_reset is that the new
operation is not allowed to manipulate libata internals directly.
It's not allowed to configure or disable the port or devices.  It can
only succeed or fail and classify attached devices into passed
@classes.

This change gives more control to higher level and eases sharing reset
methods with EH.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/scsi/libata-core.c

@@ -1485,7 +1485,24 @@ static int ata_bus_probe(struct ata_port *ap)
 {
 	unsigned int i, found = 0;
 
-	ap->ops->phy_reset(ap);
+	if (ap->ops->probe_reset) {
+		unsigned int classes[ATA_MAX_DEVICES];
+		int rc;
+
+		ata_port_probe(ap);
+
+		rc = ap->ops->probe_reset(ap, classes);
+		if (rc == 0) {
+			for (i = 0; i < ATA_MAX_DEVICES; i++)
+				ap->device[i].class = classes[i];
+		} else {
+			printk(KERN_ERR "ata%u: probe reset failed, "
+			       "disabling port\n", ap->id);
+			ata_port_disable(ap);
+		}
+	} else
+		ap->ops->phy_reset(ap);
+
 	if (ap->flags & ATA_FLAG_PORT_DISABLED)
 		goto err_out;
 

include/linux/libata.h

@@ -148,9 +148,9 @@ enum {
 	ATA_FLAG_PORT_DISABLED	= (1 << 2), /* port is disabled, ignore it */
 	ATA_FLAG_SATA		= (1 << 3),
 	ATA_FLAG_NO_LEGACY	= (1 << 4), /* no legacy mode check */
-	ATA_FLAG_SRST		= (1 << 5), /* use ATA SRST, not E.D.D. */
+	ATA_FLAG_SRST		= (1 << 5), /* (obsolete) use ATA SRST, not E.D.D. */
 	ATA_FLAG_MMIO		= (1 << 6), /* use MMIO, not PIO */
-	ATA_FLAG_SATA_RESET	= (1 << 7), /* use COMRESET */
+	ATA_FLAG_SATA_RESET	= (1 << 7), /* (obsolete) use COMRESET */
 	ATA_FLAG_PIO_DMA	= (1 << 8), /* PIO cmds via DMA */
 	ATA_FLAG_NOINTR		= (1 << 9), /* FIXME: Remove this once
 					     * proper HSM is in place. */
@@ -419,7 +419,9 @@ struct ata_port_operations {
 	u8   (*check_altstatus)(struct ata_port *ap);
 	void (*dev_select)(struct ata_port *ap, unsigned int device);
 
-	void (*phy_reset) (struct ata_port *ap);
+	void (*phy_reset) (struct ata_port *ap); /* obsolete */
+	int (*probe_reset) (struct ata_port *ap, unsigned int *classes);
+
 	void (*post_set_mode) (struct ata_port *ap);
 
 	int (*check_atapi_dma) (struct ata_queued_cmd *qc);