>Number:         1824
>Category:       port-amiga
>Synopsis:       miscellanous cleanups and optimizations
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Thu Dec  7 19:35:00 1995
>Last-Modified:
>Originator:     Ignatios Souvatzis
>Organization:
	me, myself and I
>Release:        1.1
>Environment:
	
System: NetBSD beverly.rhein.de 1.1 NetBSD 1.1 (BEVERLY) #: Thu Dec 7 12:56:53 GMT 1995 is@beverly.rhein.de:/usr/src/sys/arch/amiga/compile/BEVERLY amiga


>Description:
	Miscellanous cleanups to make the file -Wall - proof; 
	some optimizations to 
	- avoid walking the mbuf chain just to get the total length (idea 
	by Charles M. Hannum, originally intended for if_arcsubr.c); 
	- make the interupt handling faster by not keeping the same information
	in different places, leading to lots of (hopefully NOP) sanity
	checks and by avoiding access to the slow hardware at a few places;
	all of which somehow slipped the cracks before the -1.1 release.
>How-To-Repeat:
	Look at the original code and wonder how NetBSD-ARCnet managed to 
	get this fast even without the patch.
>Fix:


Index: if_bah.c
===================================================================
RCS file: /monster/cvs/src/sys/arch/amiga/dev/if_bah.c,v
retrieving revision 1.1.1.3
diff -u -r1.1.1.3 if_bah.c
--- if_bah.c	1995/10/17 12:42:42	1.1.1.3
+++ if_bah.c	1995/12/06 22:02:01
@@ -37,8 +37,9 @@
 
 #define BAHASMCOPY /**/
 #define BAHSOFTCOPY /**/
-/* #define BAHTIMINGS /**/
-/* #define BAH_DEBUG 3 /**/
+#define BAHRETRANSMIT /**/
+/* #define BAHTIMINGS */
+/* #define BAH_DEBUG 3 */
 
 #include "bpfilter.h"
 
@@ -156,9 +157,7 @@
 	u_long	sc_reconcount_excessive; /* for the above */
 #define ARC_EXCESSIVE_RECONS 20
 #define ARC_EXCESSIVE_RECONS_REWARN 400
-	u_char	sc_bufstat[4];		/* use for packet no for rx */
 	u_char	sc_intmask;
-	u_char	sc_rx_packetno;
 	u_char	sc_rx_act;		/* 2..3 */
 	u_char	sc_tx_act;		/* 0..1 */
 	u_char	sc_rx_fillcount;
@@ -181,8 +180,8 @@
 void	bah_watchdog __P((int));
 void	movepout __P((u_char *from, u_char __volatile *to, int len));
 void	movepin __P((u_char __volatile *from, u_char *to, int len));
-void	bah_srint __P((struct bah_softc *sc, void *dummy));
-void	callstart __P((struct bah_softc *sc, void *dummy));
+void	bah_srint __P((void *vsc, void *dummy));
+void	callstart __P((void *vsc, void *dummy));
 
 #ifdef BAHTIMINGS
 int	clkread();
@@ -213,7 +212,7 @@
 	struct bah_softc *sc = (void *)self;
 	struct zbus_args *zap = aux;
 	struct ifnet *ifp = &sc->sc_arccom.ac_if;
-	int i, s, linkaddress;
+	int s, linkaddress;
 
 #if (defined(BAH_DEBUG) && (BAH_DEBUG > 2))
 	printf("\n%s: attach(0x%x, 0x%x, 0x%x)\n",
@@ -228,12 +227,12 @@
 
 	sc->sc_base->kick1 = 0x0;
 	sc->sc_base->kick2 = 0x0;
-	DELAY(120);
+	DELAY(200);
 
 	sc->sc_base->kick1 = 0xFF;
 	sc->sc_base->kick2 = 0xFF;
 	do {
-		DELAY(120);
+		DELAY(200);
 	} while (!(sc->sc_base->status & ARC_POR)); 
 
 	linkaddress = sc->sc_base->dipswitches;
@@ -282,7 +281,6 @@
 #if NBPFILTER > 0
 	bpfattach(&ifp->if_bpf, ifp, DLT_ARCNET, ARC_HDRLEN);
 #endif
-
 	/* under heavy load we need four of them: */
 	alloc_sicallback();
 	alloc_sicallback();
@@ -328,7 +326,7 @@
 	struct bah_softc *sc;
 {
 	struct ifnet *ifp;
-	int i, s, linkaddress;
+	int linkaddress;
 
 	ifp = &sc->sc_arccom.ac_if;
 
@@ -339,14 +337,14 @@
 
 	sc->sc_base->kick1 = 0;
 	sc->sc_base->kick2 = 0;
-	DELAY(120);
+	DELAY(200);
 
 	/* and restart it */
 	sc->sc_base->kick1 = 0xFF;
 	sc->sc_base->kick2 = 0xFF;
 
 	do {
-		DELAY(120);
+		DELAY(200);
 	} while (!(sc->sc_base->status & ARC_POR)); 
 
 	linkaddress = sc->sc_base->dipswitches;
@@ -382,12 +380,7 @@
 	/* start receiver */
 
 	sc->sc_intmask  |= ARC_RI;
-
-	sc->sc_bufstat[2] =
-	    sc->sc_bufstat[3] =
-	    sc->sc_rx_packetno = 
-	    sc->sc_rx_fillcount = 0;
-
+	sc->sc_rx_fillcount = 0;
 	sc->sc_rx_act = 2;
 
 	sc->sc_base->command = ARC_RXBC(2);
@@ -422,8 +415,6 @@
 bah_stop(sc)
 	struct bah_softc *sc;
 {
-	int s;
-	
 	/* Stop the interrupts */
 	sc->sc_base->status = 0;
 
@@ -534,7 +525,7 @@
 	struct bah_softc *sc;
 	struct mbuf *m,*mp;
 	__volatile u_char *bah_ram_ptr;
-	int i, len, tlen, offset, s, buffer;
+	int len, tlen, offset, s, buffer;
 #ifdef BAHTIMINGS
 	u_long copystart, lencopy, perbyte;
 #endif
@@ -575,10 +566,6 @@
 		bpf_mtap(ifp->if_bpf, m);
 #endif
 
-	/* we need the data length beforehand */
-	for (mp = m, tlen=0; mp; mp = mp->m_next)
-		tlen += mp->m_len;
-
 #ifdef BAH_DEBUG
 	m = m_pullup(m,3);	/* gcc does structure padding */
 	printf("%s: start: filling %ld from %ld to %ld type %ld\n",
@@ -599,29 +586,29 @@
 	bah_ram_ptr[1 * 2] = mtod(m, u_char *)[1];
 	m_adj(m, 2);
 		
-	/* correct total length for that */
-	tlen -= 2;
+	/* get total length left at this point */
+	tlen = m->m_pkthdr.len;
 	if (tlen < ARC_MIN_FORBID_LEN) {
 		offset = 256 - tlen;
 		bah_ram_ptr[2 * 2] = offset;
 	} else {
-		if (tlen <= ARC_MAX_FORBID_LEN) 
-			offset = 512 - 3 - tlen;
+		bah_ram_ptr[2 * 2] = 0;
+		if (tlen <= ARC_MAX_FORBID_LEN)
+			offset = 255;		/* !!! */
 		else {
 			if (tlen > ARC_MAX_LEN)
 				tlen = ARC_MAX_LEN;
 			offset = 512 - tlen;
 		}
-
-		bah_ram_ptr[2 * 2] = 0;
 		bah_ram_ptr[3 * 2] = offset;
+
 	}
 	bah_ram_ptr += offset * 2;
 
-	/* lets loop again through the mbuf chain */
+	/* lets loop through the mbuf chain */
 
 	for (mp = m; mp; mp = mp->m_next) {
-		if (len = mp->m_len) {		/* YAMS */
+		if ((len = mp->m_len)) {		/* YAMS */
 #ifdef BAHTIMINGS
 			lencopy = len;
 			copystart = clkread();
@@ -690,11 +677,12 @@
 }
 
 void 
-callstart(sc, dummy)
-	struct bah_softc *sc;
-	void *dummy;
+callstart(vsc, dummy)
+	void *vsc, *dummy;
 {
+	struct bah_softc *sc;
 
+	sc = (struct bah_softc *)vsc;
 	bah_start(&sc->sc_arccom.ac_if);
 }
 
@@ -764,11 +752,11 @@
  * get the stuff out of any filled buffer we find.
  */
 void
-bah_srint(sc, dummy)
-	struct bah_softc *sc;
-	void *dummy;
+bah_srint(vsc, dummy)
+	void *vsc, *dummy;
 {
-	int buffer, buffer1, len, len1, amount, offset, s, i, type;
+	struct bah_softc *sc;
+	int buffer, len, len1, amount, offset, s, i, type;
 	u_char __volatile *bah_ram_ptr;
 	struct mbuf *m, *dst, *head;
 	struct arc_header *ah;
@@ -776,31 +764,12 @@
 #ifdef BAHTIMINGS
 	u_long copystart, lencopy, perbyte;
 #endif
-
-	head = 0;
+	sc = (struct bah_softc *)vsc;
 	ifp = &sc->sc_arccom.ac_if;
+	head = 0;
 
 	s = splimp();
-	if (sc->sc_rx_fillcount <= 1)
-		buffer = sc->sc_rx_act ^ 1;
-	else {
-
-		i = ((unsigned)(sc->sc_bufstat[2] - sc->sc_bufstat[3])) % 256;
-		if (i < 64)
-			buffer = 3;
-		else if (i > 192)
-			buffer = 2;
-		else {
-			log(LOG_WARNING,
-			    "%s: rx srint: which is older, %ld or %ld?\nn",
-			    sc->sc_dev.dv_xname,
-			    sc->sc_bufstat[2], sc->sc_bufstat[3]);
-			log(LOG_WARNING, "%s: (filled %ld)\n",
-			    sc->sc_dev.dv_xname, sc->sc_rx_fillcount);
-			splx(s);
-			return;
-		}
-	}
+	buffer = sc->sc_rx_act ^ 1;
 	splx(s);
 
 	/* Allocate header mbuf */
@@ -906,12 +875,12 @@
 	
 cleanup:
 
-	if (head == NULL)
+	if (head != NULL)
 		m_freem(head);
 
 	s = splimp();
 
-	if (--sc->sc_rx_fillcount == 1) {
+	if (--sc->sc_rx_fillcount == 2 - 1) {
 
 		/* was off, restart it on buffer just emptied */
 		sc->sc_rx_act = buffer;
@@ -930,28 +899,41 @@
 }
 
 __inline static void
-bah_tint(sc)
+bah_tint(sc, isr)
 	struct bah_softc *sc;
+	int isr;
 {
+	struct ifnet *ifp;
+
 	int buffer;
-	u_char __volatile *bah_ram_ptr;
-	int isr;
+#ifdef BAHTIMINGS
 	int clknow;
+#endif
 
+	ifp = &(sc->sc_arccom.ac_if);
 	buffer = sc->sc_tx_act;
-	isr = sc->sc_base->status;
 
 	/*
-	 * XXX insert retransmit code etc. here; and dont forget
-	 * to not retransmit if this is a timeout int.
-	 * For now just: 
+	 * retransmit code:  
+	 * Normal situtations first for fast path:
+	 * If acknowledgement received ok or broadcast, we're ok.
+	 * else if 
 	 */ 
 
-	if (!(isr & ARC_TMA) && !(sc->sc_broadcast[buffer]))
-		sc->sc_arccom.ac_if.if_oerrors++;
-	else
+	if (isr & ARC_TMA || sc->sc_broadcast[buffer])
 		sc->sc_arccom.ac_if.if_opackets++;
-
+#ifdef BAHRETRANSMIT
+	else if (ifp->if_flags & IFF_LINK2 && ifp->if_timer > 0 
+	    && --sc->sc_retransmits[buffer] > 0) {
+		/* retransmit same buffer */
+		sc->sc_base->command = ARC_TX(buffer);
+		return;
+	}
+#endif
+	else
+		ifp->if_oerrors++;
+		
+		
 #ifdef BAHTIMINGS
 	clknow = clkread();
 
@@ -963,7 +945,7 @@
 #endif
 
 	/* We know we can accept another buffer at this point. */
-	sc->sc_arccom.ac_if.if_flags &= ~IFF_OACTIVE;
+	ifp->if_flags &= ~IFF_OACTIVE;
 
 	if (--sc->sc_tx_fillcount > 0) {
 
@@ -981,7 +963,7 @@
 		 */
 		sc->sc_base->command = ARC_TX(buffer);
 		/* init watchdog timer */
-		sc->sc_arccom.ac_if.if_timer = ARCTIMEOUT;
+		ifp->if_timer = ARCTIMEOUT;
 
 #ifdef BAHTIMINGS
 		bcopy((caddr_t)&time,
@@ -1000,7 +982,7 @@
 		sc->sc_intmask &= ~ARC_TA;
 		sc->sc_base->status = sc->sc_intmask;
 		/* ... and watchdog timer */
-		sc->sc_arccom.ac_if.if_timer = 0;
+		ifp->if_timer = 0;
 
 #ifdef BAH_DEBUG
 		printf("%s: tint: no more buffers to send, status 0x%02x\n",
@@ -1026,7 +1008,6 @@
 {
 	u_char isr, maskedisr;
 	int buffer;
-	int unit;
 	u_long newsec;
 
 	isr = sc->sc_base->status;
@@ -1095,9 +1076,6 @@
 #endif
 	
 		buffer = sc->sc_rx_act;
-		sc->sc_rx_packetno = (sc->sc_rx_packetno+1)%256;
-		sc->sc_bufstat[buffer] = sc->sc_rx_packetno;
-
 		if (++sc->sc_rx_fillcount > 1) {
 			sc->sc_intmask &= ~ARC_RI;
 			sc->sc_base->status = sc->sc_intmask;
@@ -1130,7 +1108,7 @@
 	}
 
 	if (maskedisr & ARC_TA) 
-		bah_tint(sc);
+		bah_tint(sc, isr);
 
 	return (1);
 }
@@ -1166,8 +1144,6 @@
 #ifdef INET
 		case AF_INET:
 			bah_init(sc);
-			sc->sc_arccom.ac_ipaddr = IA_SIN(ifa)->sin_addr;
-			/*arpwhohas(&sc->sc_arccom, &IA_SIN(ifa)->sin_addr);*/
 			break;
 #endif
 		default:
>Audit-Trail:
>Unformatted: