[PATCH 12/14] libata-hp-prep: implement ata_noop_check_status()

[Tejun Heo <htejun@gmail.com>]

As with ops->tf_read, ops->check_status() and ops->check_altstatus()
don't make sense for controllers without single TF image.  As
->check_status() and ->check_altstatus() are deeply integrated into
libata core layer, implement ata_noop_check_status() as a temporary
measure.  This function always returns ATA_DRDY without doing
anything.

In the long term, these IO ops should be made optional and removed
from top level ata_port_operations such that driver implementing
high-level behavior don't have to bother with these.

---

 drivers/scsi/libata-core.c |   19 +++++++++++++++++++
 include/linux/libata.h     |    1 +
 2 files changed, 20 insertions(+), 0 deletions(-)

f404e622e1961647f77ef0d4bf7869e1e1dec70c
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 6d86479..2500854 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -702,6 +702,24 @@ static u64 ata_id_n_sectors(const u16 *i
 }
 
 /**
+ *	ata_noop_check_status - Fake device status reg
+ *	@ap: target port
+ *
+ *	This function performs no actual function and always returns
+ *	ATA_DRDY.
+ *
+ *	May be used as the check_status/altstatus() entry in
+ *	ata_port_operations.
+ *
+ *	LOCKING:
+ *	caller.
+ */
+u8 ata_noop_check_status(struct ata_port *ap)
+{
+	return ATA_DRDY;
+}
+
+/**
  *	ata_noop_dev_select - Select device 0/1 on ATA bus
  *	@ap: ATA channel to manipulate
  *	@device: ATA device (numbered from zero) to select
@@ -5768,6 +5786,7 @@ EXPORT_SYMBOL_GPL(ata_qc_issue_prot);
 EXPORT_SYMBOL_GPL(ata_tf_load);
 EXPORT_SYMBOL_GPL(ata_tf_read);
 EXPORT_SYMBOL_GPL(ata_noop_dev_select);
+EXPORT_SYMBOL_GPL(ata_noop_check_status);
 EXPORT_SYMBOL_GPL(ata_std_dev_select);
 EXPORT_SYMBOL_GPL(ata_tf_to_fis);
 EXPORT_SYMBOL_GPL(ata_tf_from_fis);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 5c843a8..ac8e58c 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -666,6 +666,7 @@ extern void ata_tf_load(struct ata_port 
 extern void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf);
 extern void ata_tf_to_fis(const struct ata_taskfile *tf, u8 *fis, u8 pmp);
 extern void ata_tf_from_fis(const u8 *fis, struct ata_taskfile *tf);
+extern u8 ata_noop_check_status(struct ata_port *ap);
 extern void ata_noop_dev_select (struct ata_port *ap, unsigned int device);
 extern void ata_std_dev_select (struct ata_port *ap, unsigned int device);
 extern u8 ata_check_status(struct ata_port *ap);
-- 
1.2.4