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/libata-core.c b/drivers/ata/libata-core.c
index 5f8f57a..79e3a8e 100644 (file)
--- 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 fbe6057..eb919c1 100644 (file)
--- 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 d7de7ba..e8a0d99 100644 (file)
--- 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 744beeb..0c4b271 100644 (file)
--- 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 e678af3..df64f24 100644 (file)
--- 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 cbab397..0278fd2 100644 (file)
--- 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);
        }

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 80233fd..225bfc5 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1429,6 +1429,28 @@ static inline unsigned long ata_deadline(unsigned long from_jiffies,
        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