[src/trunk]: src/sys/dev/ic Turn off AWIN_GMAC_MAC_CONF_ACS, so that all rece...

[sekiya <sekiya%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/318b5421be9e
branches:  trunk
changeset: 368874:318b5421be9e
user:      sekiya <sekiya%NetBSD.org@localhost>
date:      Tue Aug 09 23:58:46 2022 +0000

description:
Turn off AWIN_GMAC_MAC_CONF_ACS, so that all received packets retain FCS
bytes.

ether_input() can now trust M_HASFCS to accurately represent the packet
contents.

Discussed on tech-net@

diffstat:

 sys/dev/ic/dwc_gmac.c |  30 +++---------------------------
 1 files changed, 3 insertions(+), 27 deletions(-)

diffs (66 lines):

diff -r 6724c4aadeea -r 318b5421be9e sys/dev/ic/dwc_gmac.c
--- a/sys/dev/ic/dwc_gmac.c     Tue Aug 09 20:05:14 2022 +0000
+++ b/sys/dev/ic/dwc_gmac.c     Tue Aug 09 23:58:46 2022 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: dwc_gmac.c,v 1.76 2022/08/05 21:03:43 sekiya Exp $ */
+/* $NetBSD: dwc_gmac.c,v 1.77 2022/08/09 23:58:46 sekiya Exp $ */
 
 /*-
  * Copyright (c) 2013, 2014 The NetBSD Foundation, Inc.
@@ -41,7 +41,7 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(1, "$NetBSD: dwc_gmac.c,v 1.76 2022/08/05 21:03:43 sekiya Exp $");
+__KERNEL_RCSID(1, "$NetBSD: dwc_gmac.c,v 1.77 2022/08/09 23:58:46 sekiya Exp $");
 
 /* #define     DWC_GMAC_DEBUG  1 */
 
@@ -803,7 +803,6 @@
        conf |= AWIN_GMAC_MAC_CONF_FRAMEBURST
            | AWIN_GMAC_MAC_CONF_DISABLERXOWN
            | AWIN_GMAC_MAC_CONF_DISABLEJABBER
-           | AWIN_GMAC_MAC_CONF_ACS
            | AWIN_GMAC_MAC_CONF_RXENABLE
            | AWIN_GMAC_MAC_CONF_TXENABLE;
        switch (IFM_SUBTYPE(mii->mii_media_active)) {
@@ -1229,8 +1228,6 @@
        struct mbuf *m, *mnew;
        int i, len, error;
 
-       uint16_t etype;
-
        mutex_enter(&sc->sc_rxq.r_mtx);
        for (i = sc->sc_rxq.r_cur; ; i = RX_NEXT(i)) {
                bus_dmamap_sync(sc->sc_dmat, sc->sc_dma_ring_map,
@@ -1313,29 +1310,8 @@
                /* finalize mbuf */
                m->m_pkthdr.len = m->m_len = len;
                m_set_rcvif(m, ifp);
-
-#define ETYPE_OFFSET 20
-               etype = (m->m_data[ETYPE_OFFSET] << 8) + m->m_data[ETYPE_OFFSET+1];
-
-               /*
-                * The hardware doesn't trim the four FCS bytes for us, so
-                * we need to trim it ourselves.
-                * Having the upper layer remove it by passing M_HASFCS breaks
-                * protocols that don't have FCS bytes at the end of the packet
-                * (AppleTalk, for example), so we do it here instead.
-                */
+               m->m_flags |= M_HASFCS;
 
-               switch (etype) {
-                       case ETHERTYPE_ATALK:
-                       case ETHERTYPE_AARP:
-                               /* No FCS removal needed */
-                               break;
-                       default:
-                               /* remove FCS */
-                               m_adj(m, -ETHER_CRC_LEN);
-                               break;
-               }
-       
                if_percpuq_enqueue(sc->sc_ipq, m);
 
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