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>

6 files changed, 27 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 51876b93c1b7..3b822124e97e 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -74,6 +74,7 @@ const unsigned long sata_deb_timing_hotplug[]		= {  25,  500, 2000 };
 const unsigned long sata_deb_timing_long[]              = { 100, 2000, 5000 };
 
 const struct ata_port_operations ata_base_port_ops = {
+        .qc_fill_rtf            = ata_sff_qc_fill_rtf,
         .prereset               = ata_std_prereset,
         .postreset              = ata_std_postreset,
         .error_handler          = ata_std_error_handler,
@@ -4562,7 +4563,7 @@ static void fill_result_tf(struct ata_queued_cmd *qc)
         struct ata_port *ap = qc->ap;
 
         qc->result_tf.flags = qc->tf.flags;
-        ap->ops->sff_tf_read(ap, &qc->result_tf);
+        ap->ops->qc_fill_rtf(qc);
 }
 
 static void ata_verify_xfer(struct ata_queued_cmd *qc)
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);
diff --git a/drivers/ata/sata_sx4.c b/drivers/ata/sata_sx4.c
index 6107eff731f3..ec04b8d3c791 100644
--- a/drivers/ata/sata_sx4.c
+++ b/drivers/ata/sata_sx4.c
@@ -251,6 +251,7 @@ static struct ata_port_operations pdc_20621_ops = {
         .phy_reset              = pdc_20621_phy_reset,
         .qc_prep                = pdc20621_qc_prep,
         .qc_issue               = pdc20621_qc_issue,
+        .qc_fill_rtf            = ata_sff_qc_fill_rtf,
         .sff_data_xfer          = ata_sff_data_xfer,
         .eng_timeout            = pdc_eng_timeout,
         .sff_irq_clear          = pdc20621_irq_clear,
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 5bddae19d1fb..2ecd32991522 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -5280,6 +5280,7 @@ static struct ata_port_operations ipr_sata_ops = {
         .sff_tf_read = ipr_tf_read,
         .qc_prep = ata_noop_qc_prep,
         .qc_issue = ipr_qc_issue,
+        .qc_fill_rtf = ata_sff_qc_fill_rtf,
         .port_start = ata_sas_port_start,
         .port_stop = ata_sas_port_stop
 };
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index a1664b87927a..2ec255839dcd 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -356,6 +356,7 @@ static struct ata_port_operations sas_sata_ops = {
         .sff_tf_read            = sas_ata_tf_read,
         .qc_prep                = ata_noop_qc_prep,
         .qc_issue               = sas_ata_qc_issue,
+        .qc_fill_rtf            = ata_sff_qc_fill_rtf,
         .port_start             = ata_sas_port_start,
         .port_stop              = ata_sas_port_stop,
         .scr_read               = sas_ata_scr_read,
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);