ide: add ide_use_fast_pio() helper (v3)

* add ide_use_fast_pio() helper for use by host drivers

* add DMA capability and hwif->autodma checks to ide_use_dma()

  - au1xxx-ide/it8213/it821x drivers didn't check for (id->capability & 1)

    [ for the IT8211/2 in SMART mode this check shouldn't be made but since
      in it821x_fixups() we set DMA bit explicitly:

               if(strstr(id->model, "Integrated Technology Express")) {
                       /* In raid mode the ident block is slightly buggy
                          We need to set the bits so that the IDE layer knows
                          LBA28. LBA48 and DMA ar valid */
                       id->capability |= 3;            /* LBA28, DMA */

       we are better off using generic helper if we can ]

  - ide-cris driver didn't set ->autodma

    [ before the patch hwif->autodma was only checked in the chipset specific
      hwif->ide_dma_check implementations, for ide-cris it is cris_dma_check()
      function so there no behavior change here ]

v2:
* updated patch description (thanks to Alan Cox for the feedback)

v3:
* updated for scc_pata driver

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

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index 56efed6..941846c 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -680,6 +680,9 @@ int ide_use_dma(ide_drive_t *drive)
 	struct hd_driveid *id = drive->id;
 	ide_hwif_t *hwif = drive->hwif;
 
+	if ((id->capability & 1) == 0 || drive->autodma == 0)
+		return 0;
+
 	/* consult the list of known "bad" drives */
 	if (__ide_dma_bad_drive(drive))
 		return 0;