[iwn] Perform BUS_DMASYNC_PREREAD when initializing RX buffer

BUS_DMASYNC_PREREAD is required when setting up RX buffer, otherwise
data provided by card can be overwritten by data evicted from cache

Also use proper tag when setting up RX descriptor

Reviewed by:	adrian, avos, ivadasz
Differential Revision:	https://reviews.freebsd.org/D8717

diff --git a/sys/dev/iwn/if_iwn.c b/sys/dev/iwn/if_iwn.c
index b2107ae9fc5f02b60647a3eabf27df1ed4e3b3c6..f5d298bd8640169a2223b05b31833f883a1c412a 100644 (file)
--- a/sys/dev/iwn/if_iwn.c
+++ b/sys/dev/iwn/if_iwn.c
@@ -1910,6 +1910,9 @@ iwn_alloc_rx_ring(struct iwn_softc *sc, struct iwn_rx_ring *ring)
                        goto fail;
                }
 
+               bus_dmamap_sync(ring->data_dmat, data->map,
+                   BUS_DMASYNC_PREREAD);
+
                /* Set physical address of RX buffer (256-byte aligned). */
                ring->desc[i] = htole32(paddr >> 8);
        }
@@ -3040,14 +3043,19 @@ iwn_rx_done(struct iwn_softc *sc, struct iwn_rx_desc *desc,
                if (error != 0 && error != EFBIG) {
                        panic("%s: could not load old RX mbuf", __func__);
                }
+               bus_dmamap_sync(ring->data_dmat, data->map,
+                   BUS_DMASYNC_PREREAD);
                /* Physical address may have changed. */
                ring->desc[ring->cur] = htole32(paddr >> 8);
-               bus_dmamap_sync(ring->data_dmat, ring->desc_dma.map,
+               bus_dmamap_sync(ring->desc_dma.tag, ring->desc_dma.map,
                    BUS_DMASYNC_PREWRITE);
                counter_u64_add(ic->ic_ierrors, 1);
                return;
        }
 
+       bus_dmamap_sync(ring->data_dmat, data->map,
+           BUS_DMASYNC_PREREAD);
+
        m = data->m;
        data->m = m1;
        /* Update RX descriptor. */