From b9a17c6ce4dc2cd4860ca4990edb40effe0824a9 Mon Sep 17 00:00:00 2001
From: Pyun YongHyeon <yongari@FreeBSD.org>
Date: Wed, 17 Jul 2013 01:24:23 +0000
Subject: [PATCH]  o TxD ring requires 8 bytes alignment to work so change
 alignment    constraint to 8. Previously it may have triggered watchdog   
 timeouts.  o Check whether interrupt is ours or not.  o Enable interrupts
 before attemping to transmit queued packets.    This will slightly improve TX
 performance.  o No need to clear IFF_DRV_OACTIVE in a loop. AE_FLAG_TXAVAIL
 is    used to know whether there are enough available TxD ring space.  o
 Added missing bus_dmamap_sync(9) in ae_rx_intr() and rearranged    code to
 avoid unncessary register access.  o Make sure to clear TxD, TxS, RxD rings
 in driver initialization.    Otherwise some data in these rings could be
 interpreted as    'updated' which in turn will advance internally maintained 
   pointers and can trigger watchdog timeouts.

PR:	kern/180382
---
 sys/dev/ae/if_ae.c | 50 +++++++++++++++++++++++++++-------------------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/sys/dev/ae/if_ae.c b/sys/dev/ae/if_ae.c
index e49b92689ff..306a2963b4f 100644
--- a/sys/dev/ae/if_ae.c
+++ b/sys/dev/ae/if_ae.c
@@ -585,6 +585,9 @@ ae_init_locked(ae_softc_t *sc)
 	val = eaddr[0] << 8 | eaddr[1];
 	AE_WRITE_4(sc, AE_EADDR1_REG, val);
 
+	bzero(sc->rxd_base_dma, AE_RXD_COUNT_DEFAULT * 1536 + 120);
+	bzero(sc->txd_base, AE_TXD_BUFSIZE_DEFAULT);
+	bzero(sc->txs_base, AE_TXS_COUNT_DEFAULT * 4);
 	/*
 	 * Set ring buffers base addresses.
 	 */
@@ -1115,7 +1118,7 @@ ae_alloc_rings(ae_softc_t *sc)
 	 * Create DMA tag for TxD.
 	 */
 	error = bus_dma_tag_create(sc->dma_parent_tag,
-	    4, 0, BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
+	    8, 0, BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
 	    NULL, NULL, AE_TXD_BUFSIZE_DEFAULT, 1,
 	    AE_TXD_BUFSIZE_DEFAULT, 0, NULL, NULL,
 	    &sc->dma_txd_tag);
@@ -1128,7 +1131,7 @@ ae_alloc_rings(ae_softc_t *sc)
 	 * Create DMA tag for TxS.
 	 */
 	error = bus_dma_tag_create(sc->dma_parent_tag,
-	    4, 0, BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
+	    8, 0, BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
 	    NULL, NULL, AE_TXS_COUNT_DEFAULT * 4, 1,
 	    AE_TXS_COUNT_DEFAULT * 4, 0, NULL, NULL,
 	    &sc->dma_txs_tag);
@@ -1761,6 +1764,10 @@ ae_int_task(void *arg, int pending)
 	ifp = sc->ifp;
 
 	val = AE_READ_4(sc, AE_ISR_REG);	/* Read interrupt status. */
+	if (val == 0) {
+		AE_UNLOCK(sc);
+		return;
+	}
 
 	/*
 	 * Clear interrupts and disable them.
@@ -1783,12 +1790,16 @@ ae_int_task(void *arg, int pending)
 			ae_tx_intr(sc);
 		if ((val & AE_ISR_RX_EVENT) != 0)
 			ae_rx_intr(sc);
-	}
+		/*
+		 * Re-enable interrupts.
+		 */
+		AE_WRITE_4(sc, AE_ISR_REG, 0);
 
-	/*
-	 * Re-enable interrupts.
-	 */
-	AE_WRITE_4(sc, AE_ISR_REG, 0);
+		if ((sc->flags & AE_FLAG_TXAVAIL) != 0) {
+			if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
+				ae_start_locked(ifp);
+		}
+	}
 
 	AE_UNLOCK(sc);
 }
@@ -1849,10 +1860,10 @@ ae_tx_intr(ae_softc_t *sc)
 			ifp->if_oerrors++;
 
 		sc->tx_inproc--;
-
-		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
 	}
 
+	if ((sc->flags & AE_FLAG_TXAVAIL) != 0)
+		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
 	if (sc->tx_inproc < 0) {
 		if_printf(ifp, "Received stray Tx interrupt(s).\n");
 		sc->tx_inproc = 0;
@@ -1860,11 +1871,6 @@ ae_tx_intr(ae_softc_t *sc)
 
 	if (sc->tx_inproc == 0)
 		sc->wd_timer = 0;	/* Unarm watchdog. */
-	
-	if ((sc->flags & AE_FLAG_TXAVAIL) != 0) {
-		if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
-			ae_start_locked(ifp);
-	}
 
 	/*
 	 * Syncronize DMA buffers.
@@ -1923,7 +1929,7 @@ ae_rx_intr(ae_softc_t *sc)
 	ae_rxd_t *rxd;
 	struct ifnet *ifp;
 	uint16_t flags;
-	int error;
+	int count, error;
 
 	KASSERT(sc != NULL, ("[ae, %d]: sc is NULL!", __LINE__));
 
@@ -1937,7 +1943,7 @@ ae_rx_intr(ae_softc_t *sc)
 	bus_dmamap_sync(sc->dma_rxd_tag, sc->dma_rxd_map,
 	    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
 
-	for (;;) {
+	for (count = 0;; count++) {
 		rxd = (ae_rxd_t *)(sc->rxd_base + sc->rxd_cur);
 		flags = le16toh(rxd->flags);
 		if ((flags & AE_RXD_UPDATE) == 0)
@@ -1964,10 +1970,14 @@ ae_rx_intr(ae_softc_t *sc)
 		}
 	}
 
-	/*
-	 * Update Rx index.
-	 */
-	AE_WRITE_2(sc, AE_MB_RXD_IDX_REG, sc->rxd_cur);
+	if (count > 0) {
+		bus_dmamap_sync(sc->dma_rxd_tag, sc->dma_rxd_map,
+		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
+		/*
+		 * Update Rx index.
+		 */
+		AE_WRITE_2(sc, AE_MB_RXD_IDX_REG, sc->rxd_cur);
+	}
 }
 
 static void