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/include/linux/libata.h b/include/linux/libata.h
index 80233fd..225bfc5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1429,6 +1429,28 @@
return from_jiffies + msecs_to_jiffies(timeout_msecs);
}
+/* Don't open code these in drivers as there are traps. Firstly the range may
+ change in future hardware and specs, secondly 0xFF means 'no DMA' but is
+ > UDMA_0. Dyma ddreigiau */
+
+static inline int ata_using_mwdma(struct ata_device *adev)
+{
+ if (adev->dma_mode >= XFER_MW_DMA_0 && adev->dma_mode <= XFER_MW_DMA_4)
+ return 1;
+ return 0;
+}
+
+static inline int ata_using_udma(struct ata_device *adev)
+{
+ if (adev->dma_mode >= XFER_UDMA_0 && adev->dma_mode <= XFER_UDMA_7)
+ return 1;
+ return 0;
+}
+
+static inline int ata_dma_enabled(struct ata_device *adev)
+{
+ return (adev->dma_mode == 0xFF ? 0 : 1);
+}
/**************************************************************************
* PMP - drivers/ata/libata-pmp.c
