ide: add ide_set_dma() helper (v2)

* add ide_set_dma() helper and make ide_hwif_t.ide_dma_check return
  -1 when DMA needs to be disabled (== need to call ->ide_dma_off_quietly)
   0 when DMA needs to be enabled  (== need to call ->ide_dma_on)
   1 when DMA setting shouldn't be changed
* fix IDE code to use ide_set_dma() instead if using ->ide_dma_check directly

v2:
* updated for scc_pata

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/ide/pci/alim15x3.c b/drivers/ide/pci/alim15x3.c
index 2baed4e04beb..4debd18d52f8 100644
--- a/drivers/ide/pci/alim15x3.c
+++ b/drivers/ide/pci/alim15x3.c
@@ -507,17 +507,15 @@ static int config_chipset_for_dma (ide_drive_t *drive)
  *
  *      Configure a drive for DMA operation. If DMA is not possible we
  *      drop the drive into PIO mode instead.
- *
- *      FIXME: exactly what are we trying to return here
  */
- 
+
 static int ali15x3_config_drive_for_dma(ide_drive_t *drive)
 {
         ide_hwif_t *hwif        = HWIF(drive);
         struct hd_driveid *id   = drive->id;
 
         if ((m5229_revision<=0x20) && (drive->media!=ide_disk))
-                return hwif->ide_dma_off_quietly(drive);
+                goto no_dma_set;
 
         drive->init_speed = 0;
 
@@ -552,9 +550,10 @@ try_dma_modes:
 ata_pio:
                 hwif->tuneproc(drive, 255);
 no_dma_set:
-                return hwif->ide_dma_off_quietly(drive);
+                return -1;
         }
-        return hwif->ide_dma_on(drive);
+
+        return 0;
 }
 
 /**