import packblock fix from richard / bls

Reference: /n/atom/patch/applied/bcmetherusbpack
Date: Sun Jan  3 03:19:10 CET 2016
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/bcm/etherusb.c	Sun Jan  3 03:18:57 2016
+++ /sys/src/9/bcm/etherusb.c	Sun Jan  3 03:18:58 2016
@@ -125,7 +125,7 @@
 static int
 unpackasix(Ether *edev, Block *b)
 {
-	ulong hd;
+	u32int hd;
 	int m;
 	uchar *wp;
 
@@ -198,10 +198,10 @@
 
 	n = BLEN(b) & 0xFFFF;
 	n |= ~n << 16;
-	padblock(b, 4);
+	b = padblock(b, 4);
 	PUT4(b->rp, n);
 	if(BLEN(b) % ctlr->maxpkt == 0){
-		padblock(b, -4);
+		b = padblock(b, -4);
 		PUT4(b->wp, 0xFFFF0000);
 		b->wp += 4;
 	}
@@ -214,7 +214,7 @@
 	int n;
 
 	n = BLEN(b) & 0x7FF;
-	padblock(b, 8);
+	b = padblock(b, 8);
 	PUT4(b->rp, n | SmscTxfirst | SmscTxlast);
 	PUT4(b->rp+4, n);
 	transmit(ctlr, b);
@@ -263,6 +263,8 @@
 	Chan *inchan, *outchan;
 	char *buf;
 	uint bufsize, maxpkt;
+	uchar ea[Eaddrlen];
+	static char nullea[Eaddrlen];
 
 	qlock(ctlr);
 	inchan = outchan = nil;
@@ -288,9 +290,13 @@
 	inchan = namec(cb->f[2], Aopen, OREAD, 0);
 	outchan = namec(cb->f[3], Aopen, OWRITE, 0);
 	assert(inchan != nil && outchan != nil);
-	if(parsemac(ctlr->edev->ea, cb->f[4], Eaddrlen) != Eaddrlen)
+	if(parsemac(ea, cb->f[4], Eaddrlen) != Eaddrlen)
 		cmderror(cb, "bad etheraddr");
-	memmove(ctlr->edev->addr, ctlr->edev->ea, Eaddrlen);
+	if(memcmp(ctlr->edev->ea, nullea, Eaddrlen) == 0)
+		memmove(ctlr->edev->ea, ea, Eaddrlen);
+	else if(memcmp(ctlr->edev->ea, ea, Eaddrlen) != 0)
+		cmderror(cb, "wrong ether address");
+	memmove(ctlr->edev->addr, ea, Eaddrlen);
 	print("\netherusb %s: %E\n", udev->name, ctlr->edev->addr);
 	ctlr->buf = buf;
 	ctlr->inchan = inchan;
@@ -412,6 +418,11 @@
 	ctlr->edev = edev;
 }
 
+static void
+etherusbshutdown(Ether*)
+{
+}
+
 static int
 etherusbpnp(Ether* edev)
 {
@@ -425,6 +436,7 @@
 	edev->transmit = etherusbtransmit;
 	edev->ifstat = etherusbifstat;
 	edev->ctl = etherusbctl;
+	edev->shutdown = etherusbshutdown;
 	return 0;
 }