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Date:      Mon, 28 Mar 2011 00:14:56 +0000 (UTC)
From:      Pyun YongHyeon <yongari@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org
Subject:   svn commit: r220084 - stable/7/sys/dev/dc
Message-ID:  <201103280014.p2S0Eu5w074008@svn.freebsd.org>
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Author: yongari
Date: Mon Mar 28 00:14:56 2011
New Revision: 220084
URL: http://svn.freebsd.org/changeset/base/220084

Log:
  MFC r219701:
    Remove too expensive bus_dmamap_sync(9) call in dc_rx_resync().
    With this change, driver may not notice updated descriptor status
    change when bounce buffers are active. However, rxeof() in next run
    will handle the synchronization.
  
    Change dc_rxeof() a bit to return the number of processed frames in
    RX descriptor ring. Previously it returned the number of frames
    that were successfully passed to upper stack which in turn means it
    ignored frames that were discarded due to errors. The number of
    processed frames in RX descriptor ring is used to detect whether
    driver is out of sync with controller's current descriptor pointer.
    Returning number of processed frames reduces unnecessary (probably
    wrong) re-synchronization.
  
    Reviewed by:	marius

Modified:
  stable/7/sys/dev/dc/if_dc.c
Directory Properties:
  stable/7/sys/   (props changed)
  stable/7/sys/cddl/contrib/opensolaris/   (props changed)
  stable/7/sys/contrib/dev/acpica/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)

Modified: stable/7/sys/dev/dc/if_dc.c
==============================================================================
--- stable/7/sys/dev/dc/if_dc.c	Mon Mar 28 00:13:41 2011	(r220083)
+++ stable/7/sys/dev/dc/if_dc.c	Mon Mar 28 00:14:56 2011	(r220084)
@@ -238,7 +238,7 @@ static int dc_newbuf(struct dc_softc *, 
 static int dc_encap(struct dc_softc *, struct mbuf **);
 static void dc_pnic_rx_bug_war(struct dc_softc *, int);
 static int dc_rx_resync(struct dc_softc *);
-static void dc_rxeof(struct dc_softc *);
+static int dc_rxeof(struct dc_softc *);
 static void dc_txeof(struct dc_softc *);
 static void dc_tick(void *);
 static void dc_tx_underrun(struct dc_softc *);
@@ -2791,8 +2791,6 @@ dc_rx_resync(struct dc_softc *sc)
 	pos = sc->dc_cdata.dc_rx_prod;
 
 	for (i = 0; i < DC_RX_LIST_CNT; i++) {
-		bus_dmamap_sync(sc->dc_rx_ltag, sc->dc_rx_lmap,
-		    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
 		cur_rx = &sc->dc_ldata.dc_rx_list[pos];
 		if (!(le32toh(cur_rx->dc_status) & DC_RXSTAT_OWN))
 			break;
@@ -2829,18 +2827,19 @@ dc_discard_rxbuf(struct dc_softc *sc, in
  * A frame has been uploaded: pass the resulting mbuf chain up to
  * the higher level protocols.
  */
-static void
+static int
 dc_rxeof(struct dc_softc *sc)
 {
 	struct mbuf *m;
 	struct ifnet *ifp;
 	struct dc_desc *cur_rx;
-	int i, total_len;
+	int i, total_len, rx_npkts;
 	uint32_t rxstat;
 
 	DC_LOCK_ASSERT(sc);
 
 	ifp = sc->dc_ifp;
+	rx_npkts = 0;
 
 	bus_dmamap_sync(sc->dc_rx_ltag, sc->dc_rx_lmap, BUS_DMASYNC_POSTREAD |
 	    BUS_DMASYNC_POSTWRITE);
@@ -2862,6 +2861,7 @@ dc_rxeof(struct dc_softc *sc)
 		bus_dmamap_sync(sc->dc_rx_mtag, sc->dc_cdata.dc_rx_map[i],
 		    BUS_DMASYNC_POSTREAD);
 		total_len = DC_RXBYTES(rxstat);
+		rx_npkts++;
 
 		if (sc->dc_flags & DC_PNIC_RX_BUG_WAR) {
 			if ((rxstat & DC_WHOLEFRAME) != DC_WHOLEFRAME) {
@@ -2896,7 +2896,7 @@ dc_rxeof(struct dc_softc *sc)
 				else {
 					ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
 					dc_init_locked(sc);
-					return;
+					return (rx_npkts);
 				}
 			}
 		}
@@ -2942,6 +2942,7 @@ dc_rxeof(struct dc_softc *sc)
 	}
 
 	sc->dc_cdata.dc_rx_prod = i;
+	return (rx_npkts);
 }
 
 /*
@@ -3259,7 +3260,7 @@ dc_intr(void *arg)
 	struct dc_softc *sc;
 	struct ifnet *ifp;
 	uint32_t r, status;
-	int curpkts, n;
+	int n;
 
 	sc = arg;
 
@@ -3289,9 +3290,7 @@ dc_intr(void *arg)
 		CSR_WRITE_4(sc, DC_ISR, status);
 
 		if (status & DC_ISR_RX_OK) {
-			curpkts = ifp->if_ipackets;
-			dc_rxeof(sc);
-			if (curpkts == ifp->if_ipackets) {
+			if (dc_rxeof(sc) == 0) {
 				while (dc_rx_resync(sc))
 					dc_rxeof(sc);
 			}
@@ -3315,9 +3314,7 @@ dc_intr(void *arg)
 		    || (status & DC_ISR_RX_NOBUF)) {
 			r = CSR_READ_4(sc, DC_FRAMESDISCARDED);
 			ifp->if_ierrors += (r & 0xffff) + ((r >> 17) & 0x7ff);
-			curpkts = ifp->if_ipackets;
-			dc_rxeof(sc);
-			if (curpkts == ifp->if_ipackets) {
+			if (dc_rxeof(sc) == 0) {
 				while (dc_rx_resync(sc))
 					dc_rxeof(sc);
 			}

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