libata: implement and use ata_noop_irq_clear()

->irq_clear() is used to clear IRQ bit of a SFF controller and isn't
useful for drivers which don't use libata SFF HSM implementation.
However, it's a required callback and many drivers implement their own
noop version as placeholder.  This patch implements ata_noop_irq_clear
and use it to replace those custom placeholders.

Also, SFF drivers which don't support BMDMA don't need to use
ata_bmdma_irq_clear().  It becomes noop if BMDMA address isn't
initialized.  Convert them to use ata_noop_irq_clear().

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

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 9476a479691b..639298af583e 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -896,6 +896,7 @@ extern void ata_bmdma_start(struct ata_queued_cmd *qc);
 extern void ata_bmdma_stop(struct ata_queued_cmd *qc);
 extern u8   ata_bmdma_status(struct ata_port *ap);
 extern void ata_bmdma_irq_clear(struct ata_port *ap);
+extern void ata_noop_irq_clear(struct ata_port *ap);
 extern void ata_bmdma_freeze(struct ata_port *ap);
 extern void ata_bmdma_thaw(struct ata_port *ap);
 extern void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,