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>

6 files changed, 11 insertions, 11 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 5f8f57a818f..79e3a8e7a84 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3288,7 +3288,7 @@ int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
                 dev->dma_mode = ata_xfer_mask2mode(dma_mask);
 
                 found = 1;
-                if (dev->dma_mode != 0xff)
+                if (ata_dma_enabled(dev))
                         used_dma = 1;
         }
         if (!found)
@@ -3313,7 +3313,7 @@ int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 
         /* step 3: set host DMA timings */
         ata_link_for_each_dev(dev, link) {
-                if (!ata_dev_enabled(dev) || dev->dma_mode == 0xff)
+                if (!ata_dev_enabled(dev) || !ata_dma_enabled(dev))
                         continue;
 
                 dev->xfer_mode = dev->dma_mode;
diff --git a/drivers/ata/pata_acpi.c b/drivers/ata/pata_acpi.c
index fbe60571155..eb919c16a03 100644
--- a/drivers/ata/pata_acpi.c
+++ b/drivers/ata/pata_acpi.c
@@ -181,7 +181,7 @@ static unsigned int pacpi_qc_issue(struct ata_queued_cmd *qc)
 
         if (adev != acpi->last) {
                 pacpi_set_piomode(ap, adev);
-                if (adev->dma_mode)
+                if (ata_dma_enabled(adev))
                         pacpi_set_dmamode(ap, adev);
                 acpi->last = adev;
         }
diff --git a/drivers/ata/pata_atiixp.c b/drivers/ata/pata_atiixp.c
index d7de7baf58a..e8a0d99d735 100644
--- a/drivers/ata/pata_atiixp.c
+++ b/drivers/ata/pata_atiixp.c
@@ -183,7 +183,7 @@ static void atiixp_bmdma_start(struct ata_queued_cmd *qc)
         u16 tmp16;
 
         pci_read_config_word(pdev, ATIIXP_IDE_UDMA_CONTROL, &tmp16);
-        if (adev->dma_mode >= XFER_UDMA_0)
+        if (ata_using_udma(adev))
                 tmp16 |= (1 << dn);
         else
                 tmp16 &= ~(1 << dn);
diff --git a/drivers/ata/pata_cs5530.c b/drivers/ata/pata_cs5530.c
index 744beebaaf4..0c4b271a9d5 100644
--- a/drivers/ata/pata_cs5530.c
+++ b/drivers/ata/pata_cs5530.c
@@ -149,10 +149,10 @@ static unsigned int cs5530_qc_issue(struct ata_queued_cmd *qc)
         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 */
                         cs5530_set_dmamode(ap, adev);
         }
diff --git a/drivers/ata/pata_oldpiix.c b/drivers/ata/pata_oldpiix.c
index e678af383d1..df64f244300 100644
--- a/drivers/ata/pata_oldpiix.c
+++ b/drivers/ata/pata_oldpiix.c
@@ -198,7 +198,7 @@ static unsigned int oldpiix_qc_issue(struct ata_queued_cmd *qc)
 
         if (adev != ap->private_data) {
                 oldpiix_set_piomode(ap, adev);
-                if (adev->dma_mode)
+                if (ata_dma_enabled(adev))
                         oldpiix_set_dmamode(ap, adev);
         }
         return ata_sff_qc_issue(qc);
diff --git a/drivers/ata/pata_sc1200.c b/drivers/ata/pata_sc1200.c
index cbab397e3db..0278fd2b8fb 100644
--- a/drivers/ata/pata_sc1200.c
+++ b/drivers/ata/pata_sc1200.c
@@ -167,10 +167,10 @@ static unsigned int sc1200_qc_issue(struct ata_queued_cmd *qc)
         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);
         }