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, 20 insertions, 0 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 5be8a6058dac..5ae813f54420 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -1408,6 +1408,25 @@ unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc)
 }
 
 /**
+ *      ata_sff_qc_fill_rtf - fill result TF using ->sff_tf_read
+ *      @qc: qc to fill result TF for
+ *
+ *      @qc is finished and result TF needs to be filled.  Fill it
+ *      using ->sff_tf_read.
+ *
+ *      LOCKING:
+ *      spin_lock_irqsave(host lock)
+ *
+ *      RETURNS:
+ *      true indicating that result TF is successfully filled.
+ */
+bool ata_sff_qc_fill_rtf(struct ata_queued_cmd *qc)
+{
+        qc->ap->ops->sff_tf_read(qc->ap, &qc->result_tf);
+        return true;
+}
+
+/**
  *      ata_sff_host_intr - Handle host interrupt for given (port, task)
  *      @ap: Port on which interrupt arrived (possibly...)
  *      @qc: Taskfile currently active in engine
@@ -2724,6 +2743,7 @@ EXPORT_SYMBOL_GPL(ata_sff_irq_on);
 EXPORT_SYMBOL_GPL(ata_sff_irq_clear);
 EXPORT_SYMBOL_GPL(ata_sff_hsm_move);
 EXPORT_SYMBOL_GPL(ata_sff_qc_issue);
+EXPORT_SYMBOL_GPL(ata_sff_qc_fill_rtf);
 EXPORT_SYMBOL_GPL(ata_sff_host_intr);
 EXPORT_SYMBOL_GPL(ata_sff_interrupt);
 EXPORT_SYMBOL_GPL(ata_sff_freeze);