Implement ata_down_xfermask_limit(). This function manipulates
@dev->pio/mwdma/udma_mask such that the next lower transfer mode is
selected. This will be used by ata_bus_probe() rewrite and later by
EH speeding down.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 52 insertions(+), 0 deletions(-)
8360efb5b24dfe6b4cc63f00cec3648f14b105a0
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 061b0b6..5dee649 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -65,6 +65,8 @@ static unsigned int ata_dev_init_params(
struct ata_device *dev,
u16 heads,
u16 sectors);
+static int ata_down_xfermask_limit(struct ata_port *ap, struct ata_device *dev,
+ int force_pio0);
static int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev);
static unsigned int ata_dev_set_xfermode(struct ata_port *ap,
struct ata_device *dev);
@@ -1744,6 +1746,56 @@ int ata_timing_compute(struct ata_device
return 0;
}
+/**
+ * ata_down_xfermask_limit - adjust dev xfer masks downward
+ * @ap: Port associated with device @dev
+ * @dev: Device to adjust xfer masks
+ * @force_pio0: Force PIO0
+ *
+ * Adjust xfer masks of @dev downward. Note that this function
+ * does not apply the change. Invoking ata_set_mode() afterwards
+ * will apply the limit.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ * RETURNS:
+ * 0 on success, negative errno on failure
+ */
+static int ata_down_xfermask_limit(struct ata_port *ap, struct ata_device *dev,
+ int force_pio0)
+{
+ unsigned long xfer_mask;
+ int highbit;
+
+ xfer_mask = ata_pack_xfermask(dev->pio_mask, dev->mwdma_mask,
+ dev->udma_mask);
+
+ if (!xfer_mask)
+ goto fail;
+ /* don't gear down to MWDMA from UDMA, go directly to PIO */
+ if (xfer_mask & ATA_MASK_UDMA)
+ xfer_mask &= ~ATA_MASK_MWDMA;
+
+ highbit = fls(xfer_mask) - 1;
+ xfer_mask &= ~(1 << highbit);
+ if (force_pio0)
+ xfer_mask &= 1 << ATA_SHIFT_PIO;
+ if (!xfer_mask)
+ goto fail;
+
+ ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,
+ &dev->udma_mask);
+
+ printk(KERN_WARNING "ata%u: dev %u limiting speed to %s\n",
+ ap->id, dev->devno, ata_mode_string(xfer_mask));
+
+ return 0;
+
+ fail:
+ return -EINVAL;
+}
+
static int ata_dev_set_mode(struct ata_port *ap, struct ata_device *dev)
{
unsigned int err_mask;
--
1.2.4
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