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, 2 insertions, 1 deletions

diff --git a/drivers/ide/pci/ns87415.c b/drivers/ide/pci/ns87415.c
index 7f2090fac6cb..b310c4f51077 100644
--- a/drivers/ide/pci/ns87415.c
+++ b/drivers/ide/pci/ns87415.c
@@ -190,7 +190,8 @@ static int ns87415_ide_dma_setup(ide_drive_t *drive)
 static int ns87415_ide_dma_check (ide_drive_t *drive)
 {
         if (drive->media != ide_disk)
-                return HWIF(drive)->ide_dma_off_quietly(drive);
+                return -1;
+
         return __ide_dma_check(drive);
 }