IB/ipath: MAD performance sampling registers support

Add support for QLogic HCAs which have hardware performance sampling
registers for PortSamplesControl and PortSamplesResult MADs.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index 7bb0d08..a59c069 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -930,6 +930,15 @@
 		      (char __iomem *)dd->ipath_kregbase));
 }
 
+static inline void ipath_write_creg(const struct ipath_devdata *dd,
+				    ipath_creg regno, u64 value)
+{
+	if (dd->ipath_kregbase)
+		writeq(value, regno + (u64 __iomem *)
+		       (dd->ipath_cregbase +
+			(char __iomem *)dd->ipath_kregbase));
+}
+
 static inline void ipath_clear_rcvhdrtail(const struct ipath_portdata *pd)
 {
 	*((u64 *) pd->port_rcvhdrtail_kvaddr) = 0ULL;