IB/ipath: Test interrupts at driver startup

All too often, interrupts do not get enabled for our card due to BIOS
misconfiguration and other issues.  This patch checks for that
condition on startup and warns the user.  This patch is based on work
(check LID availability) by Robert Walsh.

Signed-off-by: Arthur Jones <arthur.jones@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ipath/ipath_kernel.h

@@ -297,6 +297,8 @@ struct ipath_devdata {
 	u32 ipath_lastport_piobuf;
 	/* is a stats timer active */
 	u32 ipath_stats_timer_active;
+	/* number of interrupts for this device -- saturates... */
+	u32 ipath_int_counter;
 	/* dwords sent read from counter */
 	u32 ipath_lastsword;
 	/* dwords received read from counter */
@@ -571,6 +573,9 @@ struct ipath_devdata {
 	u32 ipath_overrun_thresh_errs;
 	u32 ipath_lli_errs;
 
+	/* status check work */
+	struct delayed_work status_work;
+
 	/*
 	 * Not all devices managed by a driver instance are the same
 	 * type, so these fields must be per-device.