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Add workaround for infrequently encountered DMA engine limitation.

This commit is contained in:
jakllsch 2011-11-19 17:01:38 +00:00
parent a5b83a6434
commit dc0fd6acd4
1 changed files with 32 additions and 3 deletions
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35
sys/dev/marvell/if_mvgbe.c
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@ -1,4 +1,4 @@
/* $NetBSD: if_mvgbe.c,v 1.13 2011/09/06 19:38:23 rjs Exp $ */
/* $NetBSD: if_mvgbe.c,v 1.14 2011/11/19 17:01:38 jakllsch Exp $ */
/*
* Copyright (c) 2007, 2008 KIYOHARA Takashi
* All rights reserved.
@ -25,7 +25,7 @@
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_mvgbe.c,v 1.13 2011/09/06 19:38:23 rjs Exp $");
__KERNEL_RCSID(0, "$NetBSD: if_mvgbe.c,v 1.14 2011/11/19 17:01:38 jakllsch Exp $");
#include "rnd.h"
@ -1517,6 +1517,7 @@ mvgbe_encap(struct mvgbe_softc *sc, struct mbuf *m_head,
bus_dmamap_t txmap;
uint32_t first, current, last, cmdsts = 0;
int m_csumflags, i;
bool needs_defrag = false;
DPRINTFN(3, ("mvgbe_encap\n"));
@ -1535,6 +1536,16 @@ mvgbe_encap(struct mvgbe_softc *sc, struct mbuf *m_head,
*/
m_csumflags = m_head->m_pkthdr.csum_flags;
do_defrag:
if (__predict_false(needs_defrag == true)) {
/* A small unaligned segment was detected. */
struct mbuf *m_new;
m_new = m_defrag(m_head, M_DONTWAIT);
if (m_new == NULL)
return EFBIG;
m_head = m_new;
}
/*
* Start packing the mbufs in this chain into
* the fragment pointers. Stop when we run out
@ -1545,6 +1556,25 @@ mvgbe_encap(struct mvgbe_softc *sc, struct mbuf *m_head,
return ENOBUFS;
}
txseg = txmap->dm_segs;
if (__predict_true(needs_defrag == false)) {
/*
* Detect rarely encountered DMA limitation.
*/
for (i = 0; i < txmap->dm_nsegs; i++) {
if (((txseg[i].ds_addr & 7) != 0) &&
(txseg[i].ds_len <= 8) &&
(txseg[i].ds_len >= 1)
) {
txseg = NULL;
bus_dmamap_unload(sc->sc_dmat, txmap);
needs_defrag = true;
goto do_defrag;
}
}
}
/* Sync the DMA map. */
bus_dmamap_sync(sc->sc_dmat, txmap, 0, txmap->dm_mapsize,
BUS_DMASYNC_PREWRITE);
@ -1556,7 +1586,6 @@ mvgbe_encap(struct mvgbe_softc *sc, struct mbuf *m_head,
return ENOBUFS;
}
txseg = txmap->dm_segs;
DPRINTFN(2, ("mvgbe_encap: dm_nsegs=%d\n", txmap->dm_nsegs));