IB/ipath: prevent hardware from being accessed during reset

The reset code now turns off the PRESENT flag during a reset, so that
other code won't attempt to access a device that's in mid-reset.

Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c
index 0bcb428041f3..8e3b95b2928b 100644
--- a/drivers/infiniband/hw/ipath/ipath_intr.c
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c
@@ -719,11 +719,24 @@ static void handle_rcv(struct ipath_devdata *dd, u32 istat)
 irqreturn_t ipath_intr(int irq, void *data, struct pt_regs *regs)
 {
         struct ipath_devdata *dd = data;
-        u32 istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
+        u32 istat;
         ipath_err_t estat = 0;
         static unsigned unexpected = 0;
         irqreturn_t ret;
 
+        if(!(dd->ipath_flags & IPATH_PRESENT)) {
+                /* this is mostly so we don't try to touch the chip while
+                 * it is being reset */
+                /*
+                 * This return value is perhaps odd, but we do not want the
+                 * interrupt core code to remove our interrupt handler
+                 * because we don't appear to be handling an interrupt
+                 * during a chip reset.
+                 */
+                return IRQ_HANDLED;
+        }
+
+        istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
         if (unlikely(!istat)) {
                 ipath_stats.sps_nullintr++;
                 ret = IRQ_NONE; /* not our interrupt, or already handled */