ether8390.c

著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是bell实验室开发的Unix后继者。

}

static void
receive(Ether* ether)
{
	Dp8390 *ctlr;
	uchar curr, *p;
	Hdr hdr;
	ulong count, data, len;
	RingBuf *ring;

	ctlr = ether->ctlr;
	for(curr = getcurr(ctlr); ctlr->nxtpkt != curr; curr = getcurr(ctlr)){
		data = ctlr->nxtpkt*Dp8390BufSz;
		if(ctlr->ram)
			memmove(&hdr, (void*)(ether->mem+data), sizeof(Hdr));
		else
			_dp8390read(ctlr, &hdr, data, sizeof(Hdr));

		/*
		 * Don't believe the upper byte count, work it
		 * out from the software next-page pointer and
		 * the current next-page pointer.
		 */
		if(hdr.next > ctlr->nxtpkt)
			len = hdr.next - ctlr->nxtpkt - 1;
		else
			len = (ctlr->pstop-ctlr->nxtpkt) + (hdr.next-ctlr->pstart) - 1;
		if(hdr.len0 > (Dp8390BufSz-sizeof(Hdr)))
			len--;

		len = ((len<<8)|hdr.len0)-4;

		/*
		 * Chip is badly scrogged, reinitialise the ring.
		 */
		if(hdr.next < ctlr->pstart || hdr.next >= ctlr->pstop
		  || len < 60 || len > sizeof(Etherpkt)){
			print("dp8390: H#%2.2ux#%2.2ux#%2.2ux#%2.2ux,%lud\n",
				hdr.status, hdr.next, hdr.len0, hdr.len1, len);
			regw(ctlr, Cr, Page0|RdABORT|Stp);
			ringinit(ctlr);
			regw(ctlr, Cr, Page0|RdABORT|Sta);

			return;
		}

		/*
		 * If it's a good packet read it in to the software buffer.
		 * If the packet wraps round the hardware ring, read it in
		 * two pieces.
		 */
		ring = &ether->rb[ether->ri];
		if((hdr.status & (Fo|Fae|Crce|Prxok)) == Prxok && ring->owner == Interface){
			p = ring->pkt;
			ring->len = len;
			data += sizeof(Hdr);

			if((data+len) >= ctlr->pstop*Dp8390BufSz){
				count = ctlr->pstop*Dp8390BufSz - data;
				if(ctlr->ram)
					memmove(p, (void*)(ether->mem+data), count);
				else
					_dp8390read(ctlr, p, data, count);
				p += count;
				data = ctlr->pstart*Dp8390BufSz;
				len -= count;
			}
			if(len){
				if(ctlr->ram)
					memmove(p, (void*)(ether->mem+data), len);
				else
					_dp8390read(ctlr, p, data, len);
			}

			/*
			 * Copy the packet to whoever wants it.
			 */
			ring->owner = Host;
			ether->ri = NEXT(ether->ri, ether->nrb);
		}

		/*
		 * Finished with this packet, update the
		 * hardware and software ring pointers.
		 */
		ctlr->nxtpkt = hdr.next;

		hdr.next--;
		if(hdr.next < ctlr->pstart)
			hdr.next = ctlr->pstop-1;
		regw(ctlr, Bnry, hdr.next);
	}
}

static void
txstart(Ether* ether)
{
	int len;
	Dp8390 *ctlr;
	RingBuf *ring;
	uchar minpkt[ETHERMINTU], *rp;

	ctlr = ether->ctlr;

	/*
	 * This routine is called both from the top level and from interrupt
	 * level and expects to be called with ctlr already locked.
	 */
	if(ether->tbusy)
		return;
	ring = &ether->tb[ether->ti];
	if(ring->owner != Interface)
		return;

	/*
	 * Make sure the packet is of minimum length;
	 * copy it to the card's memory by the appropriate means;
	 * start the transmission.
	 */
	len = ring->len;
	rp = ring->pkt;
	if(len < ETHERMINTU){
		rp = minpkt;
		memmove(rp, ring->pkt, len);
		memset(rp+len, 0, ETHERMINTU-len);
		len = ETHERMINTU;
	}

	if(ctlr->ram)
		memmove((void*)(ether->mem+ctlr->tstart*Dp8390BufSz), rp, len);
	else
		dp8390write(ctlr, ctlr->tstart*Dp8390BufSz, rp, len);

	regw(ctlr, Tbcr0, len & 0xFF);
	regw(ctlr, Tbcr1, (len>>8) & 0xFF);
	regw(ctlr, Cr, Page0|RdABORT|Txp|Sta);

	ether->tbusy = 1;
}

static void
transmit(Ether* ether)
{
	Dp8390 *ctlr;

	ctlr = ether->ctlr;

	ilock(ctlr);
	txstart(ether);
	iunlock(ctlr);
}

static void
overflow(Ether *ether)
{
	Dp8390 *ctlr;
	uchar txp;
	int resend;

	ctlr = ether->ctlr;

	/*
	 * The following procedure is taken from the DP8390[12D] datasheet,
	 * it seems pretty adamant that this is what has to be done.
	 */
	txp = regr(ctlr, Cr) & Txp;
	regw(ctlr, Cr, Page0|RdABORT|Stp);
	delay(2);
	regw(ctlr, Rbcr0, 0);
	regw(ctlr, Rbcr1, 0);

	resend = 0;
	if(txp && (regr(ctlr, Isr) & (Txe|Ptx)) == 0)
		resend = 1;

	regw(ctlr, Tcr, LpbkNIC);
	regw(ctlr, Cr, Page0|RdABORT|Sta);
	receive(ether);
	regw(ctlr, Isr, Ovw);
	regw(ctlr, Tcr, LpbkNORMAL);

	if(resend)
		regw(ctlr, Cr, Page0|RdABORT|Txp|Sta);
}

static void
interrupt(Ureg*, void* arg)
{
	Ether *ether;
	Dp8390 *ctlr;
	RingBuf *ring;
	uchar isr, r;

	ether = arg;
	ctlr = ether->ctlr;

	/*
	 * While there is something of interest,
	 * clear all the interrupts and process.
	 */
	ilock(ctlr);
	regw(ctlr, Imr, 0x00);
	while(isr = (regr(ctlr, Isr) & (Cnt|Ovw|Txe|Rxe|Ptx|Prx))){
		if(isr & Ovw){
			overflow(ether);
			regw(ctlr, Isr, Ovw);
		}

		/*
		 * Packets have been received.
		 * Take a spin round the ring.
		 */
		if(isr & (Rxe|Prx)){
			receive(ether);
			regw(ctlr, Isr, Rxe|Prx);
		}

		/*
		 * A packet completed transmission, successfully or
		 * not. Start transmission on the next buffered packet,
		 * and wake the output routine.
		 */
		if(isr & (Txe|Ptx)){
			r = regr(ctlr, Tsr);
			if((isr & Txe) && (r & (Cdh|Fu|Crs|Abt))){
				print("dp8390: Tsr#%2.2ux|", r);
			}

			regw(ctlr, Isr, Txe|Ptx);

			ring = &ether->tb[ether->ti];
			ring->owner = Host;
			ether->ti = NEXT(ether->ti, ether->ntb);
			ether->tbusy = 0;
			txstart(ether);
		}

		if(isr & Cnt){
			regr(ctlr, Cntr0);
			regr(ctlr, Cntr1);
			regr(ctlr, Cntr2);
			regw(ctlr, Isr, Cnt);
		}
	}
	regw(ctlr, Imr, Cnt|Ovw|Txe|Rxe|Ptx|Prx);
	iunlock(ctlr);
}

static void
attach(Ether* ether)
{
	Dp8390 *ctlr;
	uchar r;

	ctlr = ether->ctlr;

	/*
	 * Enable the chip for transmit/receive.
	 * The init routine leaves the chip in monitor
	 * mode. Clear the missed-packet counter, it
	 * increments while in monitor mode.
	 * Sometimes there's an interrupt pending at this
	 * point but there's nothing in the Isr, so
	 * any pending interrupts are cleared and the
	 * mask of acceptable interrupts is enabled here.
	 */
	r = Ab;
	ilock(ctlr);
	regw(ctlr, Isr, 0xFF);
	regw(ctlr, Imr, Cnt|Ovw|Txe|Rxe|Ptx|Prx);
	regw(ctlr, Rcr, r);
	r = regr(ctlr, Cntr2);
	regw(ctlr, Tcr, LpbkNORMAL);
	iunlock(ctlr);
	USED(r);
}

static void
detach(Ether* ether)
{
	int timo;
	Dp8390 *ctlr;

	/*
	 * Stop the chip. Set the Stp bit and wait for the chip
	 * to finish whatever was on its tiny mind before it sets
	 * the Rst bit.
	 * The timeout is needed because there may not be a real
	 * chip there if this is called when probing for a device
	 * at boot.
	 */
	ctlr = ether->ctlr;
	regw(ctlr, Cr, Page0|RdABORT|Stp);
	regw(ctlr, Rbcr0, 0);
	regw(ctlr, Rbcr1, 0);
	for(timo = 10000; (regr(ctlr, Isr) & Rst) == 0 && timo; timo--)
			;
}

int
dp8390reset(Ether* ether)
{
	Dp8390 *ctlr;

	ctlr = ether->ctlr;

	/*
	 * This is the initialisation procedure described
	 * as 'mandatory' in the datasheet, with references
	 * to the 3C503 technical reference manual.
	 */ 
	detach(ether);
	if(ctlr->width != 1)
		regw(ctlr, Dcr, Ft4WORD|Ls|Wts);
	else
		regw(ctlr, Dcr, Ft4WORD|Ls);

	regw(ctlr, Rbcr0, 0);
	regw(ctlr, Rbcr1, 0);

	regw(ctlr, Tcr, LpbkNIC);
	regw(ctlr, Rcr, Mon);

	/*
	 * Init the ring hardware and software ring pointers.
	 * Can't initialise ethernet address as it may not be
	 * known yet.
	 */
	ringinit(ctlr);
	regw(ctlr, Tpsr, ctlr->tstart);

	/*
	 * Clear any pending interrupts and mask then all off.
	 */
	regw(ctlr, Isr, 0xFF);
	regw(ctlr, Imr, 0);

	/*
	 * Leave the chip initialised,
	 * but in monitor mode.
	 */
	regw(ctlr, Cr, Page0|RdABORT|Sta);

	/*
	 * Set up the software configuration.
	 */
	ether->attach = attach;
	ether->transmit = transmit;
	ether->interrupt = interrupt;
	ether->detach = detach;

	return 0;
}