[PATCH/RFC 3/4] CHS: support overriding the ata_rwcmd_protocol() function (resend)

[Albert Lee <albertcc@tw.ibm.com>]

(Resend for the tab problem)
Patch 3/4:
   support overriding the ata_rwcmd_protocol() function for some VIA
adapters per Alan's advice.

For your review, thanks.

Albert
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>

=======

--- ch2/include/linux/libata.h	2005-10-05 18:11:12.000000000 +0800
+++ ch3/include/linux/libata.h	2005-10-05 18:11:51.000000000 +0800
@@ -353,6 +353,8 @@ struct ata_port_operations {
  	void (*phy_reset) (struct ata_port *ap);
  	void (*post_set_mode) (struct ata_port *ap);

+	/* workaround host adapter limitations */
+	void (*rwcmd_protocol) (struct ata_queued_cmd *qc);
  	int (*check_atapi_dma) (struct ata_queued_cmd *qc);

  	void (*bmdma_setup) (struct ata_queued_cmd *qc);
--- ch2/drivers/scsi/libata-core.c	2005-10-05 18:11:12.000000000 +0800
+++ ch3/drivers/scsi/libata-core.c	2005-10-05 18:11:51.000000000 +0800
@@ -677,7 +677,14 @@ static void ata_qc_rwcmd_protocol(struct
   */
  void ata_rwcmd_protocol(struct ata_queued_cmd *qc)
  {
-	ata_qc_rwcmd_protocol(qc);
+	/* give LLD a chance to override
+	 * ex. for some VIA adapters, LLD have to use
+	 *     PIO commands if LBA48 + DMA is seen.
+	 */
+	if (qc->ap->ops->rwcmd_protocol)
+		qc->ap->ops->rwcmd_protocol(qc);
+	else
+		ata_qc_rwcmd_protocol(qc);
  }

  static const char * xfer_mode_str[] = {