libata: add qc_fill_rtf port operation

On command completion, ata_qc_complete() directly called ops->tf_read
to fill qc->result_tf.  This patch adds ops->qc_fill_rtf to replace
hardcoded ops->tf_read usage.

ata_sff_qc_fill_rtf() which uses ops->tf_read to fill result_tf is
implemented and set in ata_base_port_ops and other ops tables which
don't inherit from ata_base_port_ops, so this patch doesn't introduce
any behavior change.

ops->qc_fill_rtf() is similar to ops->sff_tf_read() but can only be
called when a command finishes.  As some non-SFF controllers don't
have TF registers defined unless they're associated with in-flight
commands, this limited operation makes life easier for those drivers
and help lifting SFF assumptions from libata core layer.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 2b5a0b77e179..bb4200d42f0d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -715,6 +715,7 @@ struct ata_port_operations {
         int  (*check_atapi_dma)(struct ata_queued_cmd *qc);
         void (*qc_prep)(struct ata_queued_cmd *qc);
         unsigned int (*qc_issue)(struct ata_queued_cmd *qc);
+        bool (*qc_fill_rtf)(struct ata_queued_cmd *qc);
 
         /*
          * Configuration and exception handling
@@ -1385,6 +1386,7 @@ extern void ata_sff_irq_clear(struct ata_port *ap);
 extern int ata_sff_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
                             u8 status, int in_wq);
 extern unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc);
+extern bool ata_sff_qc_fill_rtf(struct ata_queued_cmd *qc);
 extern unsigned int ata_sff_host_intr(struct ata_port *ap,
                                       struct ata_queued_cmd *qc);
 extern irqreturn_t ata_sff_interrupt(int irq, void *dev_instance);