enic: fix rq disable

[cascardo/linux.git] / drivers / net / ethernet / cisco / enic / vnic_rq.c

diff --git a/drivers/net/ethernet/cisco/enic/vnic_rq.c b/drivers/net/ethernet/cisco/enic/vnic_rq.c
index e572a52..36bc2c7 100644 (file)
--- a/drivers/net/ethernet/cisco/enic/vnic_rq.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_rq.c
@@ -169,19 +169,28 @@ int vnic_rq_disable(struct vnic_rq *rq)
 {
        unsigned int wait;
        struct vnic_dev *vdev = rq->vdev;
+       int i;
 
-       iowrite32(0, &rq->ctrl->enable);
+       /* Due to a race condition with clearing RQ "mini-cache" in hw, we need
+        * to disable the RQ twice to guarantee that stale descriptors are not
+        * used when this RQ is re-enabled.
+        */
+       for (i = 0; i < 2; i++) {
+               iowrite32(0, &rq->ctrl->enable);
 
-       /* Wait for HW to ACK disable request */
-       for (wait = 0; wait < 1000; wait++) {
-               if (!(ioread32(&rq->ctrl->running)))
-                       return 0;
-               udelay(10);
-       }
+               /* Wait for HW to ACK disable request */
+               for (wait = 20000; wait > 0; wait--)
+                       if (!ioread32(&rq->ctrl->running))
+                               break;
+               if (!wait) {
+                       vdev_neterr(vdev, "Failed to disable RQ[%d]\n",
+                                   rq->index);
 
-       vdev_neterr(vdev, "Failed to disable RQ[%d]\n", rq->index);
+                       return -ETIMEDOUT;
+               }
+       }
 
-       return -ETIMEDOUT;
+       return 0;
 }
 
 void vnic_rq_clean(struct vnic_rq *rq,
@@ -212,6 +221,11 @@ void vnic_rq_clean(struct vnic_rq *rq,
                        [fetch_index % VNIC_RQ_BUF_BLK_ENTRIES(count)];
        iowrite32(fetch_index, &rq->ctrl->posted_index);
 
+       /* Anytime we write fetch_index, we need to re-write 0 to rq->enable
+        * to re-sync internal VIC state.
+        */
+       iowrite32(0, &rq->ctrl->enable);
+
        vnic_dev_clear_desc_ring(&rq->ring);
 }