libata: Support chips with 64K PRD quirk

Add ata_dumb_qc_prep and supporting logic so that a driver can just
specify it needs to be helped in this area. 64K entries are split
as with drivers/ide.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 8d3e391ab8d3..a3df64677ac3 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -116,6 +116,7 @@ static inline struct device *pci_dev_to_dev(struct pci_dev *pdev)
 enum {
         /* various global constants */
         LIBATA_MAX_PRD          = ATA_MAX_PRD / 2,
+        LIBATA_DUMB_MAX_PRD     = ATA_MAX_PRD / 4,      /* Worst case */
         ATA_MAX_PORTS           = 8,
         ATA_DEF_QUEUE           = 1,
         /* tag ATA_MAX_QUEUE - 1 is reserved for internal commands */
@@ -778,6 +779,7 @@ extern void ata_data_xfer(struct ata_device *adev, unsigned char *buf,
                           unsigned int buflen, int write_data);
 extern void ata_data_xfer_noirq(struct ata_device *adev, unsigned char *buf,
                                 unsigned int buflen, int write_data);
+extern void ata_dumb_qc_prep(struct ata_queued_cmd *qc);
 extern void ata_qc_prep(struct ata_queued_cmd *qc);
 extern void ata_noop_qc_prep(struct ata_queued_cmd *qc);
 extern unsigned int ata_qc_issue_prot(struct ata_queued_cmd *qc);