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, 3 insertions, 5 deletions

diff --git a/drivers/ide/ppc/scc_pata.c b/drivers/ide/ppc/scc_pata.c
index 7e3e93caafd0..de64b022478b 100644
--- a/drivers/ide/ppc/scc_pata.c
+++ b/drivers/ide/ppc/scc_pata.c
@@ -371,15 +371,13 @@ static int scc_config_chipset_for_dma(ide_drive_t *drive)
 
 static int scc_config_drive_for_dma(ide_drive_t *drive)
 {
-        ide_hwif_t *hwif = HWIF(drive);
-
         if (ide_use_dma(drive) && scc_config_chipset_for_dma(drive))
-                return hwif->ide_dma_on(drive);
+                return 0;
 
         if (ide_use_fast_pio(drive))
-                hwif->tuneproc(drive, 4);
+                scc_tuneproc(drive, 4);
 
-        return hwif->ide_dma_off_quietly(drive);
+        return -1;
 }
 
 /**