libata: clean up xfermode / PATA timing related stuff

* s/ATA_BITS_(PIO|MWDMA|UDMA)/ATA_NR_\1_MODES/g

* Consistently use 0xff to indicate invalid transfer mode (0x00 is
  valid for PIO_SLOW).

* Make ata_xfer_mode2mask() return proper mode mask instead of just
  the highest bit.

* Sort ata_timing table in increasing xfermode order and update
  ata_timing_find_mode() accordingly.

This patch doesn't introduce any behavior change.

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

1 files changed, 12 insertions, 9 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 083dd77b120d..e2ed3bac8c5b 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -269,17 +269,20 @@ enum {
         /* encoding various smaller bitmaps into a single
          * unsigned int bitmap
          */
-        ATA_BITS_PIO            = 7,
-        ATA_BITS_MWDMA          = 5,
-        ATA_BITS_UDMA           = 8,
+        ATA_NR_PIO_MODES        = 7,
+        ATA_NR_MWDMA_MODES      = 5,
+        ATA_NR_UDMA_MODES       = 8,
 
         ATA_SHIFT_PIO           = 0,
-        ATA_SHIFT_MWDMA         = ATA_SHIFT_PIO + ATA_BITS_PIO,
-        ATA_SHIFT_UDMA          = ATA_SHIFT_MWDMA + ATA_BITS_MWDMA,
-
-        ATA_MASK_PIO            = ((1 << ATA_BITS_PIO) - 1) << ATA_SHIFT_PIO,
-        ATA_MASK_MWDMA          = ((1 << ATA_BITS_MWDMA) - 1) << ATA_SHIFT_MWDMA,
-        ATA_MASK_UDMA           = ((1 << ATA_BITS_UDMA) - 1) << ATA_SHIFT_UDMA,
+        ATA_SHIFT_MWDMA         = ATA_SHIFT_PIO + ATA_NR_PIO_MODES,
+        ATA_SHIFT_UDMA          = ATA_SHIFT_MWDMA + ATA_NR_MWDMA_MODES,
+
+        ATA_MASK_PIO            = ((1 << ATA_NR_PIO_MODES) - 1)
+                                        << ATA_SHIFT_PIO,
+        ATA_MASK_MWDMA          = ((1 << ATA_NR_MWDMA_MODES) - 1)
+                                        << ATA_SHIFT_MWDMA,
+        ATA_MASK_UDMA           = ((1 << ATA_NR_UDMA_MODES) - 1)
+                                        << ATA_SHIFT_UDMA,
 
         /* size of buffer to pad xfers ending on unaligned boundaries */
         ATA_DMA_PAD_SZ          = 4,