Hi,

a friend of mine has been complaining about watchdog timeouts on RK3588.
I compared the driver with other ones that are stable, like dwqe(4), and
found a few differences in behaviour.  One thing I noticed is that the
DMA syncs on rge_encap() most certainly don't work correctly, because it
only syncs the *last* descriptor in the chain.

I think this diff should make sure all TX descs are synced.

Cheers,
Patrick

diff --git a/sys/dev/pci/if_rge.c b/sys/dev/pci/if_rge.c
index b9d42eedfda..0b6c5e14fab 100644
--- a/sys/dev/pci/if_rge.c
+++ b/sys/dev/pci/if_rge.c
@@ -480,24 +480,27 @@ rge_encap(struct rge_queues *q, struct mbuf *m, int idx)
 
 		if (cur == RGE_TX_LIST_CNT - 1)
 			cmdsts |= RGE_TDCMDSTS_EOR;
+		if (i == (txmap->dm_nsegs - 1))
+			cmdsts |= RGE_TDCMDSTS_EOF;
 
 		d->rge_cmdsts = htole32(cmdsts);
 
+		bus_dmamap_sync(sc->sc_dmat, q->q_tx.rge_tx_list_map,
+		    cur * sizeof(struct rge_tx_desc), sizeof(struct rge_tx_desc),
+		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
+
 		last = cur;
 		cmdsts = RGE_TDCMDSTS_OWN;
 		cur = RGE_NEXT_TX_DESC(cur);
 	}
 
-	/* Set EOF on the last descriptor. */
-	d->rge_cmdsts |= htole32(RGE_TDCMDSTS_EOF);
-
 	/* Transfer ownership of packet to the chip. */
 	d = &q->q_tx.rge_tx_list[idx];
 
 	d->rge_cmdsts |= htole32(RGE_TDCMDSTS_OWN);
 
 	bus_dmamap_sync(sc->sc_dmat, q->q_tx.rge_tx_list_map,
-	    cur * sizeof(struct rge_tx_desc), sizeof(struct rge_tx_desc),
+	    idx * sizeof(struct rge_tx_desc), sizeof(struct rge_tx_desc),
 	    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
 
 	/* Update info of TX queue and descriptors. */