[PATCH] libata: implement ata_down_xfermask_limit()
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 to improve ata_bus_probe() failure
handling and later by EH.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 3ddfbe1..68fa64d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -65,6 +65,8 @@
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_down_sata_spd_limit(struct ata_port *ap);
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,
@@ -1859,6 +1861,56 @@
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;