Partial sync with FreeBSD, mostly bugfixes from Luigi Rizzo (ok jason@)

-Remove m_devget on non-STRICT_ALIGNMENT architectures, supposedly a 50-70%
 performance increase for peak packet forwarding on the Soekris 486/133 on fbsd

-Fix a bug in the driver -- under load, the receive unit could become
 idle and the driver would not detect the event, requiring userland
 to cycle the interface to bring it up again.

 The fix consists in adding SIS_IMR_RX_IDLE to the interrupt mask and
 add a command in sis_intr() to restart the receiver when this happens.

-While at it, make the test of status bits more efficient

-Slightly simplify the code to initialize the ring buffers

-Add VLAN support (Accept Long Packets)

2 files changed, 60 insertions, 45 deletions

diff --git a/sys/dev/pci/if_sis.c b/sys/dev/pci/if_sis.c
index 48650c37bd6..5b1cc530efd 100644
--- a/sys/dev/pci/if_sis.c
+++ b/sys/dev/pci/if_sis.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_sis.c,v 1.19 2001/11/06 19:53:19 miod Exp $ */
+/*	$OpenBSD: if_sis.c,v 1.20 2002/02/08 04:43:24 chris Exp $ */
 /*
  * Copyright (c) 1997, 1998, 1999
  *	Bill Paul <wpaul@ctr.columbia.edu>.  All rights reserved.
@@ -59,6 +59,7 @@
  */
 
 #include "bpfilter.h"
+#include "vlan.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -852,6 +853,10 @@ void sis_attach(parent, self, aux)
 	IFQ_SET_READY(&ifp->if_snd);
 	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
 
+#if NVLAN > 0
+	ifp->if_capabilities |= IFCAP_VLAN_MTU;
+#endif
+
 	sc->sc_mii.mii_ifp = ifp;
 	sc->sc_mii.mii_readreg = sis_miibus_readreg;
 	sc->sc_mii.mii_writereg = sis_miibus_writereg;
@@ -886,23 +891,17 @@ int sis_list_tx_init(sc)
 {
 	struct sis_list_data	*ld;
 	struct sis_ring_data	*cd;
-	int			i;
+	int			i, nexti;
 
 	cd = &sc->sis_cdata;
 	ld = sc->sis_ldata;
 
 	for (i = 0; i < SIS_TX_LIST_CNT; i++) {
-		if (i == (SIS_TX_LIST_CNT - 1)) {
-			ld->sis_tx_list[i].sis_nextdesc =
-			    &ld->sis_tx_list[0];
-			ld->sis_tx_list[i].sis_next =
-			    vtophys(&ld->sis_tx_list[0]);
-		} else {
-			ld->sis_tx_list[i].sis_nextdesc =
-			    &ld->sis_tx_list[i + 1];
-			ld->sis_tx_list[i].sis_next =
-			    vtophys(&ld->sis_tx_list[i + 1]);
-		}
+		nexti = (i == (SIS_TX_LIST_CNT - 1)) ? 0 : i+1;
+		ld->sis_tx_list[i].sis_nextdesc =
+		    &ld->sis_tx_list[nexti];
+		ld->sis_tx_list[i].sis_next =
+		    vtophys(&ld->sis_tx_list[nexti]);
 		ld->sis_tx_list[i].sis_mbuf = NULL;
 		ld->sis_tx_list[i].sis_ptr = 0;
 		ld->sis_tx_list[i].sis_ctl = 0;
@@ -924,7 +923,7 @@ int sis_list_rx_init(sc)
 {
 	struct sis_list_data	*ld;
 	struct sis_ring_data	*cd;
-	int			i;
+	int			i, nexti;
 
 	ld = sc->sis_ldata;
 	cd = &sc->sis_cdata;
@@ -932,17 +931,11 @@ int sis_list_rx_init(sc)
 	for (i = 0; i < SIS_RX_LIST_CNT; i++) {
 		if (sis_newbuf(sc, &ld->sis_rx_list[i], NULL) == ENOBUFS)
 			return(ENOBUFS);
-		if (i == (SIS_RX_LIST_CNT - 1)) {
-			ld->sis_rx_list[i].sis_nextdesc =
-			    &ld->sis_rx_list[0];
-			ld->sis_rx_list[i].sis_next =
-			    vtophys(&ld->sis_rx_list[0]);
-		} else {
-			ld->sis_rx_list[i].sis_nextdesc =
-			    &ld->sis_rx_list[i + 1];
-			ld->sis_rx_list[i].sis_next =
-			    vtophys(&ld->sis_rx_list[i + 1]);
-		}
+		nexti = (i == (SIS_RX_LIST_CNT - 1)) ? 0 : i+1;
+		ld->sis_rx_list[i].sis_nextdesc =
+		    &ld->sis_rx_list[nexti];
+		ld->sis_rx_list[i].sis_next =
+		    vtophys(&ld->sis_rx_list[nexti]);
 	}
 
 	cd->sis_rx_prod = 0;
@@ -1008,7 +1001,6 @@ void sis_rxeof(sc)
 	i = sc->sis_cdata.sis_rx_prod;
 
 	while(SIS_OWNDESC(&sc->sis_ldata->sis_rx_list[i])) {
-		struct mbuf		*m0 = NULL;
 
 		cur_rx = &sc->sis_ldata->sis_rx_list[i];
 		rxstat = cur_rx->sis_rxstat;
@@ -1032,15 +1024,33 @@ void sis_rxeof(sc)
 		}
 
 		/* No errors; receive the packet. */	
-		m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
-		    total_len + ETHER_ALIGN, 0, ifp, NULL);
-		sis_newbuf(sc, cur_rx, m);
-		if (m0 == NULL) {
-			ifp->if_ierrors++;
-			continue;
+#ifndef __STRICT_ALIGNMENT
+		/*
+		 * On some architectures, we do not have alignment problems,
+		 * so try to allocate a new buffer for the receive ring, and
+		 * pass up the one where the packet is already, saving the
+		 * expensive copy done in m_devget().
+		 * If we are on an architecture with alignment problems, or
+		 * if the allocation fails, then use m_devget and leave the
+		 * existing buffer in the receive ring.
+		 */
+		if (sis_newbuf(sc, cur_rx, NULL) == 0) {
+			m->m_pkthdr.rcvif = ifp;
+			m->m_pkthdr.len = m->m_len = total_len;
+		} else
+#endif
+		{
+			struct mbuf *m0;
+			m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
+			    total_len + ETHER_ALIGN, 0, ifp, NULL);
+			sis_newbuf(sc, cur_rx, m);
+			if (m0 == NULL) {
+				ifp->if_ierrors++;
+				continue;
+			}
+			m_adj(m0, ETHER_ALIGN);
+			m = m0;
 		}
-		m_adj(m0, ETHER_ALIGN);
-		m = m0;
 
 		ifp->if_ipackets++;
 
@@ -1189,20 +1199,21 @@ int sis_intr(arg)
 
 		claimed = 1;
 
-		if ((status & SIS_ISR_TX_DESC_OK) ||
-		    (status & SIS_ISR_TX_ERR) ||
-		    (status & SIS_ISR_TX_OK) ||
-		    (status & SIS_ISR_TX_IDLE))
+		if (status &
+		    (SIS_ISR_TX_DESC_OK | SIS_ISR_TX_ERR |
+		     SIS_ISR_TX_OK | SIS_ISR_TX_IDLE))
 			sis_txeof(sc);
 
-		if ((status & SIS_ISR_RX_DESC_OK) ||
-		    (status & SIS_ISR_RX_OK))
+		if (status &
+		    (SIS_ISR_RX_DESC_OK | SIS_ISR_RX_OK |
+		     SIS_ISR_RX_IDLE))
 			sis_rxeof(sc);
 
-		if ((status & SIS_ISR_RX_ERR) ||
-		    (status & SIS_ISR_RX_OFLOW)) {
+		if (status & (SIS_ISR_RX_ERR | SIS_ISR_RX_OFLOW))
 			sis_rxeoc(sc);
-		}
+
+		if (status & (SIS_ISR_RX_IDLE))
+			SIS_SETBIT(sc, SIS_CSR, SIS_CSR_RX_ENABLE);
 
 		if (status & SIS_ISR_SYSERR) {
 			sis_reset(sc);
@@ -1432,6 +1443,9 @@ void sis_init(xsc)
 	/* Set RX configuration */
 	CSR_WRITE_4(sc, SIS_RX_CFG, SIS_RXCFG);
 
+	/* Accept Long Packets for VLAN support */
+	SIS_SETBIT(sc, SIS_RX_CFG, SIS_RXCFG_RX_JABBER);
+
 	/* Set TX configuration */
 	if (IFM_SUBTYPE(mii->mii_media_active) == IFM_10_T)
 		CSR_WRITE_4(sc, SIS_TX_CFG, SIS_TXCFG_10);
diff --git a/sys/dev/pci/if_sisreg.h b/sys/dev/pci/if_sisreg.h
index 0f2f0310d32..3869bfdb1eb 100644
--- a/sys/dev/pci/if_sisreg.h
+++ b/sys/dev/pci/if_sisreg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_sisreg.h,v 1.7 2001/09/23 22:41:25 aaron Exp $ */
+/*	$OpenBSD: if_sisreg.h,v 1.8 2002/02/08 04:43:24 chris Exp $ */
 /*
  * Copyright (c) 1997, 1998, 1999
  *	Bill Paul <wpaul@ee.columbia.edu>.  All rights reserved.
@@ -187,6 +187,7 @@
 #define SIS_INTRS	\
 	(SIS_IMR_RX_OFLOW|SIS_IMR_TX_UFLOW|SIS_IMR_TX_OK|\
 	 SIS_IMR_TX_IDLE|SIS_IMR_RX_OK|SIS_IMR_RX_ERR|\
+	 SIS_IMR_RX_IDLE|\
 	 SIS_IMR_SYSERR)
 
 #define SIS_IER_INTRENB		0x00000001
@@ -307,7 +308,7 @@ struct sis_desc {
 
 #define SIS_LASTDESC(x)		(!((x)->sis_ctl & SIS_CMDSTS_MORE)))
 #define SIS_OWNDESC(x)		((x)->sis_ctl & SIS_CMDSTS_OWN)
-#define SIS_INC(x, y)		(x) = (x + 1) % y
+#define SIS_INC(x, y)		{ if (++(x) == y) x=0 ; }
 #define SIS_RXBYTES(x)		((x)->sis_ctl & SIS_CMDSTS_BUFLEN)
 
 #define SIS_RXSTAT_COLL		0x00010000