pci.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

		 * the maximum as it's not known how many buses are behind
		 * this one; the final value is set on the way back up.
		 */
		sbn = pcicfgr8(p, PciSBN);
		ubn = pcicfgr8(p, PciUBN);

		if(sbn == 0 || ubn == 0) {
			sbn = maxubn+1;
			/*
			 * Make sure memory, I/O and master enables are
			 * off, set the primary, secondary and subordinate
			 * bus numbers and clear the secondary status before
			 * attempting to scan the secondary bus.
			 *
			 * Initialisation of the bridge should be done here.
			 */
			pcicfgw32(p, PciPCR, 0xFFFF0000);
			l = (MaxUBN<<16)|(sbn<<8)|bno;
			pcicfgw32(p, PciPBN, l);
			pcicfgw16(p, PciSPSR, 0xFFFF);
			maxubn = pcilscan(sbn, &p->bridge);
			l = (maxubn<<16)|(sbn<<8)|bno;

			pcicfgw32(p, PciPBN, l);
		}
		else {
			maxubn = ubn;
			pcilscan(sbn, &p->bridge);
		}
	}

	return maxubn;
}

int
pciscan(int bno, Pcidev **list)
{
	int ubn;

	qlock(&pcicfginitlock);
	ubn = pcilscan(bno, list);
	qunlock(&pcicfginitlock);
	return ubn;
}

static void
pcicfginit(void)
{
	char *p;
	int bno;
	Pcidev **list;
	ulong mema, ioa;

	qlock(&pcicfginitlock);
	if(pcicfgmode != -1)
		goto out;

	/*
	 * Try to determine which PCI configuration mode is implemented.
	 * Mode2 uses a byte at 0xCF8 and another at 0xCFA; Mode1 uses
	 * a DWORD at 0xCF8 and another at 0xCFC and will pass through
	 * any non-DWORD accesses as normal I/O cycles. There shouldn't be
	 * a device behind these addresses so if Mode2 accesses fail try
	 * for Mode1 (which is preferred, Mode2 is deprecated).
	 */
	outb(PciCSE, 0);
	if(inb(PciCSE) == 0){
		pcicfgmode = 2;
		pcimaxdno = 15;
	}
	else {
		outl(PciADDR, 0);
		if(inl(PciADDR) == 0){
			pcicfgmode = 1;
			pcimaxdno = 31;
		}
	}
	
	if(pcicfgmode < 0)
		goto out;

	fmtinstall('T', tbdffmt);

	if(p = getconf("*pcimaxbno"))
		pcimaxbno = strtoul(p, 0, 0);
	if(p = getconf("*pcimaxdno"))
		pcimaxdno = strtoul(p, 0, 0);

	list = &pciroot;
	for(bno = 0; bno <= pcimaxbno; bno++) {
		int sbno = bno;
		bno = pcilscan(bno, list);

		while(*list)
			list = &(*list)->link;

		if (sbno == 0) {
			Pcidev *pci;

			/*
			  * If we have found a PCI-to-Cardbus bridge, make sure
			  * it has no valid mappings anymore.  
			  */
			pci = pciroot;
			while (pci) {
				if (pci->ccrb == 6 && pci->ccru == 7) {
					ushort bcr;

					/* reset the cardbus */
					bcr = pcicfgr16(pci, PciBCR);
					pcicfgw16(pci, PciBCR, 0x40 | bcr);
					delay(50);
				}
				pci = pci->link;
			}
		}
	}

	if(pciroot == nil)
		goto out;

	/*
	 * Work out how big the top bus is
	 */
	mema = 0;
	ioa = 0;
	pcibusmap(pciroot, &mema, &ioa, 0);

	DBG("Sizes: mem=%8.8lux size=%8.8lux io=%8.8lux\n",
		mema, pcimask(mema), ioa);

	/*
	 * Align the windows and map it
	 */
	ioa = 0x1000;
	mema = 0;

	pcilog("Mask sizes: mem=%lux io=%lux\n", mema, ioa);

	pcibusmap(pciroot, &mema, &ioa, 1);
	DBG("Sizes2: mem=%lux io=%lux\n", mema, ioa);

out:
	qunlock(&pcicfginitlock);
}

static int
pcicfgrw8(int tbdf, int rno, int data, int read)
{
	int o, type, x;

	if(pcicfgmode == -1)
		pcicfginit();

	if(BUSBNO(tbdf))
		type = 0x01;
	else
		type = 0x00;
	x = -1;
	if(BUSDNO(tbdf) > pcimaxdno)
		return x;

	lock(&pcicfglock);
	switch(pcicfgmode){

	case 1:
		o = rno & 0x03;
		rno &= ~0x03;
		outl(PciADDR, 0x80000000|BUSBDF(tbdf)|rno|type);
		if(read)
			x = inb(PciDATA+o);
		else
			outb(PciDATA+o, data);
		outl(PciADDR, 0);
		break;

	case 2:
		outb(PciCSE, 0x80|(BUSFNO(tbdf)<<1));
		outb(PciFORWARD, BUSBNO(tbdf));
		if(read)
			x = inb((0xC000|(BUSDNO(tbdf)<<8)) + rno);
		else
			outb((0xC000|(BUSDNO(tbdf)<<8)) + rno, data);
		outb(PciCSE, 0);
		break;
	}
	unlock(&pcicfglock);

	return x;
}

int
pcicfgr8(Pcidev* pcidev, int rno)
{
	return pcicfgrw8(pcidev->tbdf, rno, 0, 1);
}

void
pcicfgw8(Pcidev* pcidev, int rno, int data)
{
	pcicfgrw8(pcidev->tbdf, rno, data, 0);
}

static int
pcicfgrw16(int tbdf, int rno, int data, int read)
{
	int o, type, x;

	if(pcicfgmode == -1)
		pcicfginit();

	if(BUSBNO(tbdf))
		type = 0x01;
	else
		type = 0x00;
	x = -1;
	if(BUSDNO(tbdf) > pcimaxdno)
		return x;

	lock(&pcicfglock);
	switch(pcicfgmode){

	case 1:
		o = rno & 0x02;
		rno &= ~0x03;
		outl(PciADDR, 0x80000000|BUSBDF(tbdf)|rno|type);
		if(read)
			x = ins(PciDATA+o);
		else
			outs(PciDATA+o, data);
		outl(PciADDR, 0);
		break;

	case 2:
		outb(PciCSE, 0x80|(BUSFNO(tbdf)<<1));
		outb(PciFORWARD, BUSBNO(tbdf));
		if(read)
			x = ins((0xC000|(BUSDNO(tbdf)<<8)) + rno);
		else
			outs((0xC000|(BUSDNO(tbdf)<<8)) + rno, data);
		outb(PciCSE, 0);
		break;
	}
	unlock(&pcicfglock);

	return x;
}

int
pcicfgr16(Pcidev* pcidev, int rno)
{
	return pcicfgrw16(pcidev->tbdf, rno, 0, 1);
}

void
pcicfgw16(Pcidev* pcidev, int rno, int data)
{
	pcicfgrw16(pcidev->tbdf, rno, data, 0);
}

static int
pcicfgrw32(int tbdf, int rno, int data, int read)
{
	int type, x;

	if(pcicfgmode == -1)
		pcicfginit();

	if(BUSBNO(tbdf))
		type = 0x01;
	else
		type = 0x00;
	x = -1;
	if(BUSDNO(tbdf) > pcimaxdno)
		return x;

	lock(&pcicfglock);
	switch(pcicfgmode){

	case 1:
		rno &= ~0x03;
		outl(PciADDR, 0x80000000|BUSBDF(tbdf)|rno|type);
		if(read)
			x = inl(PciDATA);
		else
			outl(PciDATA, data);
		outl(PciADDR, 0);
		break;

	case 2:
		outb(PciCSE, 0x80|(BUSFNO(tbdf)<<1));
		outb(PciFORWARD, BUSBNO(tbdf));
		if(read)
			x = inl((0xC000|(BUSDNO(tbdf)<<8)) + rno);
		else
			outl((0xC000|(BUSDNO(tbdf)<<8)) + rno, data);
		outb(PciCSE, 0);
		break;
	}
	unlock(&pcicfglock);

	return x;
}

int
pcicfgr32(Pcidev* pcidev, int rno)
{
	return pcicfgrw32(pcidev->tbdf, rno, 0, 1);
}

void
pcicfgw32(Pcidev* pcidev, int rno, int data)
{
	pcicfgrw32(pcidev->tbdf, rno, data, 0);
}

Pcidev*
pcimatch(Pcidev* prev, int vid, int did)
{
	if(pcicfgmode == -1)
		pcicfginit();

	if(prev == nil)
		prev = pcilist;
	else
		prev = prev->list;

	while(prev != nil){
		if((vid == 0 || prev->vid == vid)
		&& (did == 0 || prev->did == did))
			break;
		prev = prev->list;
	}
	return prev;
}

Pcidev*
pcimatchtbdf(int tbdf)
{
	Pcidev *pcidev;

	if(pcicfgmode == -1)
		pcicfginit();

	for(pcidev = pcilist; pcidev != nil; pcidev = pcidev->list) {
		if(pcidev->tbdf == tbdf)
			break;
	}
	return pcidev;
}

uchar
pciipin(Pcidev *pci, uchar pin)
{
	if (pci == nil)
		pci = pcilist;

	while (pci) {
		uchar intl;

		if (pcicfgr8(pci, PciINTP) == pin && pci->intl != 0 && pci->intl != 0xff)
			return pci->intl;

		if (pci->bridge && (intl = pciipin(pci->bridge, pin)) != 0)
			return intl;

		pci = pci->list;
	}
	return 0;
}

static void
pcilhinv(Pcidev* p)
{
	int i;
	Pcidev *t;

	if(p == nil) {
		putstrn(PCICONS.output, PCICONS.ptr);
		p = pciroot;
		print("bus dev type vid  did intl memory\n");
	}
	for(t = p; t != nil; t = t->link) {
		print("%d  %2d/%d %.2ux %.2ux %.2ux %.4ux %.4ux %3d  ",
			BUSBNO(t->tbdf), BUSDNO(t->tbdf), BUSFNO(t->tbdf),
			t->ccrb, t->ccru, t->ccrp, t->vid, t->did, t->intl);

		for(i = 0; i < nelem(p->mem); i++) {
			if(t->mem[i].size == 0)
				continue;
			print("%d:%.8lux %d ", i,
				t->mem[i].bar, t->mem[i].size);
		}
		if(t->ioa.bar || t->ioa.size)
			print("ioa:%.8lux %d ", t->ioa.bar, t->ioa.size);
		if(t->mema.bar || t->mema.size)
			print("mema:%.8lux %d ", t->mema.bar, t->mema.size);
		if(t->bridge)
			print("->%d", BUSBNO(t->bridge->tbdf));
		print("\n");
	}
	while(p != nil) {
		if(p->bridge != nil)
			pcilhinv(p->bridge);
		p = p->link;
	}	
}

void
pcihinv(Pcidev* p)
{
	if(pcicfgmode == -1)
		pcicfginit();
	qlock(&pcicfginitlock);
	pcilhinv(p);
	qunlock(&pcicfginitlock);
}

void
pcireset(void)
{
	Pcidev *p;
	int pcr;

	if(pcicfgmode == -1)
		pcicfginit();

	for(p = pcilist; p != nil; p = p->list){
		pcr = pcicfgr16(p, PciPCR);
		pcr &= ~0x0004;
		pcicfgw16(p, PciPCR, pcr);
	}
}

void
pcisetbme(Pcidev* p)
{
	int pcr;

	pcr = pcicfgr16(p, PciPCR);
	pcr |= MASen;
	pcicfgw16(p, PciPCR, pcr);
}

void
pciclrbme(Pcidev* p)
{
	int pcr;

	pcr = pcicfgr16(p, PciPCR);
	pcr &= ~MASen;
	pcicfgw16(p, PciPCR, pcr);
}