bge: Limit BCM5701 B5 to 32-bit mode

This is a workaround for a bug which causes data corruption in
combination with certain bridges.

Obtained-from: FreeBSD 185812

diff --git a/sys/dev/netif/bge/if_bge.c b/sys/dev/netif/bge/if_bge.c
index 9f58abb..6f44e62 100644 (file)
--- a/sys/dev/netif/bge/if_bge.c
+++ b/sys/dev/netif/bge/if_bge.c
@@ -1296,6 +1296,16 @@ bge_chipinit(struct bge_softc *sc)
            BGE_MODECTL_TX_NO_PHDR_CSUM);
 
        /*
+        * BCM5701 B5 have a bug causing data corruption when using
+        * 64-bit DMA reads, which can be terminated early and then
+        * completed later as 32-bit accesses, in combination with
+        * certain bridges.
+        */
+       if (sc->bge_asicrev == BGE_ASICREV_BCM5701 &&
+           sc->bge_chipid == BGE_CHIPID_BCM5701_B5)
+               BGE_SETBIT(sc, BGE_MODE_CTL, BGE_MODECTL_FORCE_PCI32);
+
+       /*
         * Disable memory write invalidate.  Apparently it is not supported
         * properly by these devices.
         */