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, 0 deletions

diff --git a/include/linux/ide.h b/include/linux/ide.h
index 579a8521de63..08f96e8a1902 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1278,6 +1278,7 @@ int __ide_dma_good_drive(ide_drive_t *);
 int ide_use_dma(ide_drive_t *);
 int __ide_dma_off(ide_drive_t *);
 void ide_dma_verbose(ide_drive_t *);
+int ide_set_dma(ide_drive_t *);
 ide_startstop_t ide_dma_intr(ide_drive_t *);
 
 #ifdef CONFIG_BLK_DEV_IDEDMA_PCI
@@ -1303,6 +1304,7 @@ extern int __ide_dma_timeout(ide_drive_t *);
 static inline int ide_use_dma(ide_drive_t *drive) { return 0; }
 static inline int __ide_dma_off(ide_drive_t *drive) { return 0; }
 static inline void ide_dma_verbose(ide_drive_t *drive) { ; }
+static inline int ide_set_dma(ide_drive_t *drive) { return 1; }
 #endif /* CONFIG_BLK_DEV_IDEDMA */
 
 #ifndef CONFIG_BLK_DEV_IDEDMA_PCI