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, 6 insertions, 3 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 52c85af7fe99..7b61562cdd40 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1276,7 +1276,7 @@ static int ata_eh_speed_down(struct ata_device *dev, int is_io,
                 return ATA_EH_HARDRESET;
 
         /* lower transfer mode */
-        if (ata_down_xfermask_limit(dev, 0) == 0)
+        if (ata_down_xfermask_limit(dev, ATA_DNXFER_ANY) == 0)
                 return ATA_EH_SOFTRESET;
 
         ata_dev_printk(dev, KERN_ERR,
@@ -1965,6 +1965,7 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
         struct ata_eh_context *ehc = &ap->eh_context;
         struct ata_device *dev;
         int down_xfermask, i, rc;
+        int dnxfer_sel;
 
         DPRINTK("ENTER\n");
 
@@ -2064,8 +2065,10 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                 sata_down_spd_limit(ap);
         default:
                 ehc->tries[dev->devno]--;
-                if (down_xfermask &&
-                    ata_down_xfermask_limit(dev, ehc->tries[dev->devno] == 1))
+                dnxfer_sel = ATA_DNXFER_ANY;
+                if (ehc->tries[dev->devno] == 1)
+                        dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
+                if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
                         ehc->tries[dev->devno] = 0;
         }