libata: improve ata_down_xfermask_limit()

Make ata_down_xfermask_limit() accept @sel instead of @force_pio0.
@sel selects how the xfermask limit will be adjusted.  The following
selectors are defined.

* ATA_DNXFER_PIO	: only speed down PIO
* ATA_DNXFER_DMA	: only speed down DMA, don't cause transfer mode change
* ATA_DNXFER_40C	: apply 40c cable limit
* ATA_DNXFER_FORCE_PIO	: force PIO
* ATA_DNXFER_FORCE_PIO0	: force PIO0 (same as original with @force_pio0 == 1)
* ATA_DNXFER_ANY	: same as original with @force_pio0 == 0

Currently, only ANY and FORCE_PIO0 are used to maintain the original
behavior.  Other selectors will be used later to improve EH speed down
sequence.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 0ad7781d72a3..8533de67d87e 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -41,6 +41,16 @@ struct ata_scsi_args {
 enum {
         /* flags for ata_dev_read_id() */
         ATA_READID_POSTRESET    = (1 << 0), /* reading ID after reset */
+
+        /* selector for ata_down_xfermask_limit() */
+        ATA_DNXFER_PIO          = 0,    /* speed down PIO */
+        ATA_DNXFER_DMA          = 1,    /* speed down DMA */
+        ATA_DNXFER_40C          = 2,    /* apply 40c cable limit */
+        ATA_DNXFER_FORCE_PIO    = 3,    /* force PIO */
+        ATA_DNXFER_FORCE_PIO0   = 4,    /* force PIO0 */
+        ATA_DNXFER_ANY          = 5,    /* speed down any */
+
+        ATA_DNXFER_QUIET        = (1 << 31),
 };
 
 extern struct workqueue_struct *ata_aux_wq;
@@ -69,7 +79,7 @@ extern int ata_dev_revalidate(struct ata_device *dev, unsigned int flags);
 extern int ata_dev_configure(struct ata_device *dev);
 extern int sata_down_spd_limit(struct ata_port *ap);
 extern int sata_set_spd_needed(struct ata_port *ap);
-extern int ata_down_xfermask_limit(struct ata_device *dev, int force_pio0);
+extern int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel);
 extern int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev);
 extern void ata_sg_clean(struct ata_queued_cmd *qc);
 extern void ata_qc_free(struct ata_queued_cmd *qc);