ether8139.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

	ctlr = edev->ctlr;
	qlock(&ctlr->alock);
	if(ctlr->alloc == nil){
		ctlr->rblen = 1<<((Rblen>>RblenSHIFT)+13);
		ctlr->alloc = mallocz(ctlr->rblen+16 + Ntd*Tdbsz + 32, 0);
		rtl8139init(edev);
	}
	qunlock(&ctlr->alock);
}

static void
rtl8139txstart(Ether* edev)
{
	Td *td;
	int size;
	Block *bp;
	Ctlr *ctlr;

	ctlr = edev->ctlr;
	while(ctlr->ntd < Ntd){
		bp = etheroq(edev);
		if(bp == nil)
			break;
		size = BLEN(bp);

		td = &ctlr->td[ctlr->tdh];
		if(((int)bp->rp) & 0x03){
			memmove(td->data, bp->rp, size);
			freeb(bp);
			csr32w(ctlr, td->tsad, PCIWADDR(td->data));
			ctlr->tunaligned++;
		}
		else{
			td->bp = bp;
			csr32w(ctlr, td->tsad, PCIWADDR(bp->rp));
			ctlr->taligned++;
		}
		csr32w(ctlr, td->tsd, (ctlr->etxth<<EtxthSHIFT)|size);

		ctlr->ntd++;
		ctlr->tdh = NEXT(ctlr->tdh, Ntd);
	}
}

static void
rtl8139transmit(Ether* edev)
{
	Ctlr *ctlr;

	ctlr = edev->ctlr;
	ilock(&ctlr->tlock);
	rtl8139txstart(edev);
	iunlock(&ctlr->tlock);
}

static void
rtl8139receive(Ether* edev)
{
	Block *bp;
	Ctlr *ctlr;
	ushort capr;
	uchar cr, *p;
	int l, length, status;

	ctlr = edev->ctlr;

	/*
	 * Capr is where the host is reading from,
	 * Cbr is where the NIC is currently writing.
	 */
	capr = (csr16r(ctlr, Capr)+16) % ctlr->rblen;
	while(!(csr8r(ctlr, Cr) & Bufe)){
		p = ctlr->rbstart+capr;

		/*
		 * Apparently the packet length may be 0xFFF0 if
		 * the NIC is still copying the packet into memory.
		 */
		length = (*(p+3)<<8)|*(p+2);
		if(length == 0xFFF0)
			break;
		status = (*(p+1)<<8)|*p;

		if(!(status & Rcok)){
#ifndef FS
			if(status & (Ise|Fae))
				edev->frames++;
			if(status & Crc)
				edev->crcs++;
			if(status & (Runt|Long))
				edev->buffs++;
#endif
			/*
			 * Reset the receiver.
			 * Also may have to restore the multicast list
			 * here too if it ever gets used.
			 */
			cr = csr8r(ctlr, Cr);
			csr8w(ctlr, Cr, cr & ~Re);
			csr32w(ctlr, Rbstart, PCIWADDR(ctlr->rbstart));
			csr8w(ctlr, Cr, cr);
			csr32w(ctlr, Rcr, ctlr->rcr);

			continue;
		}

		/*
		 * Receive Completed OK.
		 * Very simplistic; there are ways this could be done
		 * without copying, but the juice probably isn't worth
		 * the squeeze.
		 * The packet length includes a 4 byte CRC on the end.
		 */
		capr = (capr+4) % ctlr->rblen;
		p = ctlr->rbstart+capr;
		capr = (capr+length) % ctlr->rblen;

		if((bp = iallocb(length)) != nil){
			SETWPCNT(bp, 0);
			if(p+length >= ctlr->rbstart+ctlr->rblen){
				l = ctlr->rbstart+ctlr->rblen - p;
				memmove(ENDDATA(bp), p, l);
				INCRPTR(bp, l);
				length -= l;
				p = ctlr->rbstart;
			}
			if(length > 0){
				memmove(ENDDATA(bp), p, length);
				INCRPTR(bp, length);
			}
			INCRPTR(bp, -4);
			if (BLEN(bp) < 0) {
				print("rtl8139receive: input packet of negative length\n");
				SETWPCNT(bp, 0);
				freeb(bp);
			} else
				ETHERIQ(edev, bp, 1);
		}

		capr = ROUNDUP(capr, 4);
		csr16w(ctlr, Capr, capr-16);
	}
}

static void
rtl8139interrupt(Ureg*, void* arg)
{
	Td *td;
	Ctlr *ctlr;
	Ether *edev;
	int isr, msr, tsd;

	edev = arg;
	ctlr = edev->ctlr;

	while((isr = csr16r(ctlr, Isr)) != 0){
		csr16w(ctlr, Isr, isr);
		if(isr & (Fovw|PunLc|Rxovw|Rer|Rok)){
			rtl8139receive(edev);
			if(!(isr & Rok))
				ctlr->ierrs++;
			isr &= ~(Fovw|Rxovw|Rer|Rok);
		}

		if(isr & (Ter|Tok)){
			ilock(&ctlr->tlock);
			while(ctlr->ntd){
				td = &ctlr->td[ctlr->tdi];
				tsd = csr32r(ctlr, td->tsd);
				if(!(tsd & (Tabt|Tun|Tcok)))
					break;

				if(!(tsd & Tcok)){
					if(tsd & Tun){
						if(ctlr->etxth < ETHERMAXTU/32)
							ctlr->etxth++;
					}
#ifndef FS
					edev->oerrs++;
#endif
				}

				if(td->bp != nil){
					freeb(td->bp);
					td->bp = nil;
				}

				ctlr->ntd--;
				ctlr->tdi = NEXT(ctlr->tdi, Ntd);
			}
			rtl8139txstart(edev);
			iunlock(&ctlr->tlock);
			isr &= ~(Ter|Tok);
		}

		if(isr & PunLc){
			/*
			 * Maybe the link changed - do we care very much?
			 */
			msr = csr8r(ctlr, Msr);
			if(!(msr & Linkb)){
				if(!(msr & Speed10) && edev->mbps != 100){
					edev->mbps = 100;
					qsetlimit(edev->oq, 256*1024);
				}
				else if((msr & Speed10) && edev->mbps != 10){
					edev->mbps = 10;
					qsetlimit(edev->oq, 65*1024);
				}
			}
			isr &= ~(Clc|PunLc);
		}

		/*
		 * Only Serr|Timerbit should be left by now.
		 * Should anything be done to tidy up? TimerInt isn't
		 * used so that can be cleared. A PCI bus error is indicated
		 * by Serr, that's pretty serious; is there anyhing to do
		 * other than try to reinitialise the chip?
		 */
		if(isr != 0){
			iprint("rtl8139interrupt: imr %4.4ux isr %4.4ux\n",
				csr16r(ctlr, Imr), isr);
			if(isr & Timerbit)
				csr32w(ctlr, TimerInt, 0);
			if(isr & Serr)
				rtl8139init(edev);
		}
	}
}

static Ctlr*
rtl8139match(Ether* edev, int id)
{
	int port;
	Pcidev *p;
	Ctlr *ctlr;

	/*
	 * Any adapter matches if no edev->port is supplied,
	 * otherwise the ports must match.
	 */
	for(ctlr = ctlrhead; ctlr != nil; ctlr = ctlr->next){
		if(ctlr->active)
			continue;
		p = ctlr->pcidev;
		if(((p->did<<16)|p->vid) != id)
			continue;
		port = p->mem[0].bar & ~0x01;
		if(edev->port != 0 && edev->port != port)
			continue;

		if(ioalloc(port, p->mem[0].size, 0, "rtl8139") < 0){
			print("rtl8139: port 0x%ux in use\n", port);
			continue;
		}

		ctlr->port = port;
		if(rtl8139reset(ctlr))
			continue;
		pcisetbme(p);

		ctlr->active = 1;
		return ctlr;
	}
	return nil;
}

static struct {
	char*	name;
	int	id;
} rtl8139pci[] = {
	{ "rtl8139",	(0x8139<<16)|0x10EC, },	/* generic */
	{ "smc1211",	(0x1211<<16)|0x1113, },	/* SMC EZ-Card */
	{ "dfe-538tx",	(0x1300<<16)|0x1186, }, /* D-Link DFE-538TX */
	{ "dfe-560txd",	(0x1340<<16)|0x1186, }, /* D-Link DFE-560TXD */
	{ nil },
};

int
rtl8139pnp(Ether* edev)
{
	int i, id;
	Pcidev *p;
	Ctlr *ctlr;
	uchar ea[Eaddrlen];

	/*
	 * Make a list of all ethernet controllers
	 * if not already done.
	 */
	if(ctlrhead == nil){
		p = nil;
		while(p = pcimatch(p, 0, 0)){
#ifdef FS
			if(p->ccru != ((0x02<<8)|0x00))
#else
			if(p->ccrb != 0x02 || p->ccru != 0)
#endif
				continue;
			ctlr = malloc(sizeof(Ctlr));
			ctlr->pcidev = p;
			ctlr->id = (p->did<<16)|p->vid;

			if(ctlrhead != nil)
				ctlrtail->next = ctlr;
			else
				ctlrhead = ctlr;
			ctlrtail = ctlr;
		}
	}

	/*
	 * Is it an RTL8139 under a different name?
	 * Normally a search is made through all the found controllers
	 * for one which matches any of the known vid+did pairs.
	 * If a vid+did pair is specified a search is made for that
	 * specific controller only.
	 */
	id = 0;
	for(i = 0; i < edev->nopt; i++){
		if(cistrncmp(edev->opt[i], "id=", 3) == 0)
			id = strtol(&edev->opt[i][3], nil, 0);
	}

	ctlr = nil;
	if(id != 0)
		ctlr = rtl8139match(edev, id);
	else for(i = 0; rtl8139pci[i].name; i++){
		if((ctlr = rtl8139match(edev, rtl8139pci[i].id)) != nil)
			break;
	}
	if(ctlr == nil)
		return -1;

	edev->ctlr = ctlr;
	edev->port = ctlr->port;
	edev->irq = ctlr->pcidev->intl;
	edev->tbdf = ctlr->pcidev->tbdf;

	/*
	 * Check if the adapter's station address is to be overridden.
	 * If not, read it from the device and set in edev->ea.
	 */
	memset(ea, 0, Eaddrlen);
	if(memcmp(ea, edev->ea, Eaddrlen) == 0){
		i = csr32r(ctlr, Idr0);
		edev->ea[0] = i;
		edev->ea[1] = i>>8;
		edev->ea[2] = i>>16;
		edev->ea[3] = i>>24;
		i = csr32r(ctlr, Idr0+4);
		edev->ea[4] = i;
		edev->ea[5] = i>>8;
	}

	edev->attach = rtl8139attach;
	edev->transmit = rtl8139transmit;
	edev->interrupt = rtl8139interrupt;
#ifndef FS
	edev->ifstat = rtl8139ifstat;

	edev->arg = edev;
	edev->promiscuous = rtl8139promiscuous;
#endif

	/*
	 * This should be much more dynamic but will do for now.
	 */
	if((csr8r(ctlr, Msr) & (Speed10|Linkb)) == 0)
		edev->mbps = 100;

	return 0;
}

void
ether8139link(void)
{
	addethercard("rtl8139", rtl8139pnp);
}

void
ether8139bothlink(void)
{
	ether8139link();
}