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-rw-r--r--drivers/scsi/libata-bmdma.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/scsi/libata-bmdma.c b/drivers/scsi/libata-bmdma.c
index a89e44b21f4d..999725ca8d09 100644
--- a/drivers/scsi/libata-bmdma.c
+++ b/drivers/scsi/libata-bmdma.c
@@ -700,5 +700,41 @@ err_out:
return rc;
}
+/**
+ * ata_pci_clear_simplex - attempt to kick device out of simplex
+ * @pdev: PCI device
+ *
+ * Some PCI ATA devices report simplex mode but in fact can be told to
+ * enter non simplex mode. This implements the neccessary logic to
+ * perform the task on such devices. Calling it on other devices will
+ * have -undefined- behaviour.
+ */
+
+int ata_pci_clear_simplex(struct pci_dev *pdev)
+{
+ unsigned long bmdma = pci_resource_start(pdev, 4);
+ u8 simplex;
+
+ if (bmdma == 0)
+ return -ENOENT;
+
+ simplex = inb(bmdma + 0x02);
+ outb(simplex & 0x60, bmdma + 0x02);
+ simplex = inb(bmdma + 0x02);
+ if (simplex & 0x80)
+ return -EOPNOTSUPP;
+ return 0;
+}
+
+unsigned long ata_pci_default_filter(const struct ata_port *ap, struct ata_device *adev, unsigned long xfer_mask)
+{
+ /* Filter out DMA modes if the device has been configured by
+ the BIOS as PIO only */
+
+ if (ap->ioaddr.bmdma_addr == 0)
+ xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
+ return xfer_mask;
+}
+
#endif /* CONFIG_PCI */