libata: Fix a large collection of DMA mode mismatches
Dave Müller sent a diff for the pata_oldpiix that highlighted a problem
where a lot of the ATA drivers assume dma_mode == 0 means "no DMA" while
the core code uses 0xFF.
This turns out to have other consequences such as code doing >= XFER_UDMA_0
also catching 0xFF as UDMAlots. Fortunately it doesn't generally affect
set_dma_mode, although some drivers call back into their own set mode code
from other points.
Having been through the drivers I've added helpers for using_udma/using_mwdma
dma_enabled so that people don't open code ranges that may change (eg if UDMA8
appears somewhere)
Thanks to David for the initial bits
[and added fix for pata_oldpiix from and signed-off-by Dave Mueller
<dave.mueller@gmx.ch> -jg]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/pata_sc1200.c b/drivers/ata/pata_sc1200.c
index cbab397..0278fd2 100644
--- a/drivers/ata/pata_sc1200.c
+++ b/drivers/ata/pata_sc1200.c
@@ -167,10 +167,10 @@
struct ata_device *prev = ap->private_data;
/* See if the DMA settings could be wrong */
- if (adev->dma_mode != 0 && adev != prev && prev != NULL) {
+ if (ata_dma_enabled(adev) && adev != prev && prev != NULL) {
/* Maybe, but do the channels match MWDMA/UDMA ? */
- if ((adev->dma_mode >= XFER_UDMA_0 && prev->dma_mode < XFER_UDMA_0) ||
- (adev->dma_mode < XFER_UDMA_0 && prev->dma_mode >= XFER_UDMA_0))
+ if ((ata_using_udma(adev) && !ata_using_udma(prev)) ||
+ (ata_using_udma(prev) && !ata_using_udma(adev)))
/* Switch the mode bits */
sc1200_set_dmamode(ap, adev);
}