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/ide.c b/drivers/ide/ide.c
index fbc6d39ace68..5585c01a9b7f 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1135,7 +1135,8 @@ static int set_using_dma (ide_drive_t *drive, int arg)
         if (HWIF(drive)->ide_dma_check == NULL)
                 return -EPERM;
         if (arg) {
-                if (HWIF(drive)->ide_dma_check(drive)) return -EIO;
+                if (ide_set_dma(drive))
+                        return -EIO;
                 if (HWIF(drive)->ide_dma_on(drive)) return -EIO;
         } else {
                 if (__ide_dma_off(drive))