usbuhci.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

static void
canceltds(Ctlr *ctlr, QH *q, Endpt *e)
{
	TD *t;

	if(q != nil){
		ilock(ctlr);
		for(t = q->first; t != nil; t = t->next)
			if(t->ep == e)
				t->flags |= CancelTD;
		iunlock(ctlr);
		XPRINT("cancel:\n");
		dumpqh(q);
	}
}

static void
eptcancel(Ctlr *ctlr, Endpt *e)
{
	Endptx *x;

	if(e == nil)
		return;
	x = e->private;
	canceltds(ctlr, x->epq, e);
	canceltds(ctlr, ctlr->ctlq, e);
	canceltds(ctlr, ctlr->bulkq, e);
}

static void
eptactivate(Ctlr *ctlr, Endpt *e)
{
	ilock(&ctlr->activends);
	if(e->active == 0){
		XPRINT("activate 0x%p\n", e);
		e->active = 1;
		e->activef = ctlr->activends.f;
		ctlr->activends.f = e;
	}
	iunlock(&ctlr->activends);
}

static void
eptdeactivate(Ctlr *ctlr, Endpt *e)
{
	Endpt **l;

	/* could be O(1) but not worth it yet */
	ilock(&ctlr->activends);
	if(e->active){
		e->active = 0;
		XPRINT("deactivate 0x%p\n", e);
		for(l = &ctlr->activends.f; *l != e; l = &(*l)->activef)
			if(*l == nil){
				iunlock(&ctlr->activends);
				panic("usb eptdeactivate");
			}
		*l = e->activef;
	}
	iunlock(&ctlr->activends);
}

static void
queueqh(Ctlr *ctlr, QH *qh)
{
	QH *q;

	// See if it's already queued
	for (q = ctlr->recvq->next; q; q = q->hlink)
		if (q == qh)
			return;
	if ((qh->hlink = ctlr->recvq->next) == nil)
		qh->head = Terminate;
	else
		qh->head = PCIWADDR(ctlr->recvq->next) | IsQH;
	ctlr->recvq->next = qh;
	ctlr->recvq->entries = PCIWADDR(qh) | IsQH;
}

static QH*
qxmit(Ctlr *ctlr, Endpt *e, Block *b, int pid)
{
	TD *t;
	int n, vf;
	QH *qh;
	Endptx *x;

	x = e->private;
	if(b != nil){
		n = BLEN(b);
		t = alloctde(ctlr, e, pid, n);
		t->bp = b;
		t->buffer = PCIWADDR(b->rp);
	}else
		t = alloctde(ctlr, e, pid, 0);
	ilock(ctlr);
	e->ntd++;
	iunlock(ctlr);
	if(e->debug) pprint("QTD: %8.8lux n=%ld\n", t, b?BLEN(b): 0);
	vf = 0;
	if(e->x == 0){
		qh = ctlr->ctlq;
		vf = 0;
	}else if((qh = x->epq) == nil || e->mode != OWRITE){
		qh = ctlr->bulkq;
		vf = Vf;
	}
	queuetd(ctlr, qh, t, vf, "qxmit");
	return qh;
}

static QH*
qrcv(Ctlr *ctlr, Endpt *e)
{
	TD *t;
	Block *b;
	QH *qh;
	int vf;
	Endptx *x;

	x = e->private;
	t = alloctde(ctlr, e, TokIN, e->maxpkt);
	b = allocb(e->maxpkt);
	t->bp = b;
	t->buffer = PCIWADDR(b->wp);
	vf = 0;
	if(e->x == 0){
		qh = ctlr->ctlq;
	}else if((qh = x->epq) == nil || e->mode != OREAD){
		qh = ctlr->bulkq;
		vf = Vf;
	}
	queuetd(ctlr, qh, t, vf, "qrcv");
	return qh;
}

static int
usbsched(Ctlr *ctlr, int pollms, ulong load)
{
	int i, d, q;
	ulong best, worst;

	best = 1000000;
	q = -1;
	for (d = 0; d < pollms; d++){
		worst = 0;
		for (i = d; i < NFRAME; i++){
			if (ctlr->frameld[i] + load > worst)
				worst = ctlr->frameld[i] + load;
		}
		if (worst < best){
			best = worst;
			q = d;
		}
	}
	return q;
}

static int
schedendpt(Ctlr *ctlr, Endpt *e)
{
	TD *td;
	Endptx *x;
	uchar *bp;
	int i, id, ix, size, frnum;

	if(!e->iso || e->sched >= 0)
		return 0;

	if (e->active){
		return -1;
	}
	e->off = 0;
	e->sched = usbsched(ctlr, e->pollms, e->maxpkt);
	if(e->sched < 0)
		return -1;

	x = e->private;
	if (x->tdalloc || x->bpalloc)
		panic("usb: tdalloc/bpalloc");
	x->tdalloc = mallocz(0x10 + NFRAME*sizeof(TD), 1);
	x->bpalloc = mallocz(0x10 + e->maxpkt*NFRAME/e->pollms, 1);
	x->td0 = (TD*)(((ulong)x->tdalloc + 0xf) & ~0xf);
	x->bp0 = (uchar *)(((ulong)x->bpalloc + 0xf) & ~0xf);
	frnum = (IN(Frnum) + 1) & 0x3ff;
	frnum = (frnum & ~(e->pollms - 1)) + e->sched;
	x->xtd = &x->td0[(frnum+8)&0x3ff];	/* Next td to finish */
	x->etd = nil;
	e->remain = 0;
	e->nbytes = 0;
	td = x->td0;
	for(i = e->sched; i < NFRAME; i += e->pollms){
		bp = x->bp0 + e->maxpkt*i/e->pollms;
		td->buffer = PCIWADDR(bp);
		td->ep = e;
		td->next = &td[1];
		ctlr->frameld[i] += e->maxpkt;
		td++;
	}
	td[-1].next = x->td0;
	for(i = e->sched; i < NFRAME; i += e->pollms){
		ix = (frnum+i) & 0x3ff;
		td = &x->td0[ix];

		id = (e->x<<7)|(e->dev->x&0x7F);
		if (e->mode == OREAD)
			/* enable receive on this entry */
			td->dev = ((e->maxpkt-1)<<21) | ((id&0x7FF)<<8) | TokIN;
		else{
			size = (e->hz + e->remain)*e->pollms/1000;
			e->remain = (e->hz + e->remain)*e->pollms%1000;
			size *= e->samplesz;
			td->dev = ((size-1)<<21) | ((id&0x7FF)<<8) | TokOUT;
		}
		td->status = ErrLimit1 | Active | IsoSelect | IOC;
		td->link = ctlr->frames[ix];
		td->flags |= IsoClean;
		ctlr->frames[ix] = PCIWADDR(td);
	}
	return 0;
}

static void
unschedendpt(Ctlr *ctlr, Endpt *e)
{
	int q;
	TD *td;
	Endptx *x;
	ulong *addr;

	if(!e->iso || e->sched < 0)
		return;

	x = e->private;
	if (x->tdalloc == nil)
		panic("tdalloc");
	for (q = e->sched; q < NFRAME; q += e->pollms){
		td = x->td0++;
		addr = &ctlr->frames[q];
		while(*addr != PADDR(td)) {
			if(*addr & IsQH)
				panic("usb: TD expected");
			addr = &TFOL(*addr)->link;
		}
		*addr = td->link;
		ctlr->frameld[q] -= e->maxpkt;
	}
	free(x->tdalloc);
	free(x->bpalloc);
	x->tdalloc = nil;
	x->bpalloc = nil;
	x->etd = nil;
	x->td0 = nil;
	e->sched = -1;
}

static void
epalloc(Usbhost *uh, Endpt *e)
{
	Endptx *x;

	x = malloc(sizeof(Endptx));
	e->private = x;
	x->epq = allocqh(uh->ctlr);
	if(x->epq == nil)
		panic("devendptx");
}

static void
epfree(Usbhost *uh, Endpt *e)
{
	Ctlr *ctlr;
	Endptx *x;

	ctlr = uh->ctlr;
	x = e->private;
	if(x->epq != nil)
		freeqh(ctlr, x->epq);
}

static void
epopen(Usbhost *uh, Endpt *e)
{
	Ctlr *ctlr;

	ctlr = uh->ctlr;
	if(e->iso && e->active)
		error("already open");
	if(schedendpt(ctlr, e) < 0){
		if(e->active)
			error("cannot schedule USB endpoint, active");
		else
			error("cannot schedule USB endpoint");
	}
	eptactivate(ctlr, e);
}

static void
epclose(Usbhost *uh, Endpt *e)
{
	Ctlr *ctlr;

	ctlr = uh->ctlr;
	eptdeactivate(ctlr, e);
	unschedendpt(ctlr, e);
}

static void
epmode(Usbhost *uh, Endpt *e)
{
	Ctlr *ctlr;
	Endptx *x;

	ctlr = uh->ctlr;
	x = e->private;
	if(e->iso) {
		if(x->epq != nil) {
			freeqh(ctlr, x->epq);
			x->epq = nil;
		}
	}
	else {
		/* Each bulk device gets a queue head hanging off the
		 * bulk queue head
		 */
		if(x->epq == nil) {
			x->epq = allocqh(ctlr);
			if(x->epq == nil)
				panic("epbulk: allocqh");
		}
		queueqh(ctlr, x->epq);
	}
}

static	int	ioport[] = {-1, Portsc0, Portsc1};

static void
portreset(Usbhost *uh, int port)
{
	int i, p;
	Ctlr *ctlr;

	ctlr = uh->ctlr;
	if(port != 1 && port != 2)
		error(Ebadarg);

	/* should check that device not being configured on other port? */
	p = ioport[port];
	qlock(&ctlr->resetl);
	if(waserror()){
		qunlock(&ctlr->resetl);
		nexterror();
	}
	XPRINT("r: %x\n", IN(p));
	ilock(ctlr);
	OUT(p, PortReset);
	delay(12);	/* BUG */
	XPRINT("r2: %x\n", IN(p));
	OUT(p, IN(p) & ~PortReset);
	XPRINT("r3: %x\n", IN(p));
	OUT(p, IN(p) | PortEnable);
	microdelay(64);
	for(i=0; i<1000 && (IN(p) & PortEnable) == 0; i++)
		;
	XPRINT("r': %x %d\n", IN(p), i);
	OUT(p, (IN(p) & ~PortReset)|PortEnable);
	iunlock(ctlr);
	poperror();
	qunlock(&ctlr->resetl);
}

static void
portenable(Usbhost *uh, int port, int on)
{
	int w, p;
	Ctlr *ctlr;

	ctlr = uh->ctlr;
	if(port != 1 && port != 2)
		error(Ebadarg);

	/* should check that device not being configured on other port? */
	p = ioport[port];
	qlock(&ctlr->resetl);
	if(waserror()){
		qunlock(&ctlr->resetl);
		nexterror();
	}
	ilock(ctlr);
	w = IN(p);
	if(on)
		w |= PortEnable;
	else
		w &= ~PortEnable;
	OUT(p, w);
	microdelay(64);
	iunlock(ctlr);
	XPRINT("e: %x\n", IN(p));
	poperror();
	qunlock(&ctlr->resetl);
}

static void
portinfo(Usbhost *uh, char *s, char *se)
{
	int x, i, j;
	Ctlr *ctlr;

	ctlr = uh->ctlr;
	for(i = 1; i <= 2; i++) {
		ilock(ctlr);
		x = IN(ioport[i]);
		if((x & (PortChange|StatusChange)) != 0)
			OUT(ioport[i], x);
		iunlock(ctlr);
		s = seprint(s, se, "%d %ux", i, x);
		for(j = 0; j < nelem(portstatus); j++) {
			if((x & portstatus[j].bit) != 0)
				s = seprint(s, se, " %s", portstatus[j].name);
		}
		s = seprint(s, se, "\n");
	}
}

static void
cleaniso(Endpt *e, int frnum)
{
	TD *td;
	int id, n, i;
	Endptx *x;
	uchar *bp;

	x = e->private;
	td = x->xtd;
	if (td->status & Active)
		return;
	id = (e->x<<7)|(e->dev->x&0x7F);
	do {
		if (td->status & AnyError)
			XPRINT("usbisoerror 0x%lux\n", td->status);
		n = (td->status + 1) & 0x3ff;
		e->nbytes += n;
		if ((td->flags & IsoClean) == 0)
			e->nblocks++;
		if (e->mode == OREAD){
			e->buffered += n;
			e->poffset += (td->status + 1) & 0x3ff;
			td->offset = e->poffset;
			td->dev = ((e->maxpkt -1)<<21) | ((id&0x7FF)<<8) | TokIN;
			e->toffset = td->offset;
		}else{
			if ((td->flags & IsoClean) == 0){
				e->buffered -= n;
				if (e->buffered < 0){
//					print("e->buffered %d?\n", e->buffered);
					e->buffered = 0;
				}
			}
			e->toffset = td->offset;
			n = (e->hz + e->remain)*e->pollms/1000;
			e->remain = (e->hz + e->remain)*e->pollms%1000;
			n *= e->samplesz;
			td->dev = ((n -1)<<21) | ((id&0x7FF)<<8) | TokOUT;
			td->offset = e->poffset;
			e->poffset += n;
		}
		td = td->next;
		if (x->xtd == td){
			XPRINT("@");
			break;
		}
	} while ((td->status & Active) == 0);
	e->time = todget(nil);
	x->xtd = td;
	for (n = 2; n < 4; n++){
		i = ((frnum + n)&0x3ff);
		td = x->td0 + i;
		bp = x->bp0 + e->maxpkt*i/e->pollms;
		if (td->status & Active)
			continue;

		if (e->mode == OWRITE){
			if (td == x->etd) {
				XPRINT("*");
				memset(bp+e->off, 0, e->maxpkt-e->off);
				if (e->off == 0)
					td->flags |= IsoClean;
				else
					e->buffered += (((td->dev>>21) +1) & 0x3ff) - e->off;
				x->etd = nil;
			}else if ((td->flags & IsoClean) == 0){
				XPRINT("-");
				memset(bp, 0, e->maxpkt);
				td->flags |= IsoClean;
			}
		} else {
			/* Unread bytes are now lost */
			e->buffered -= (td->status + 1) & 0x3ff;
		}
		td->status = ErrLimit1 | Active | IsoSelect | IOC;
	}
	wakeup(&e->wr);
}

static void
interrupt(Ureg*, void *a)
{
	QH *q;
	Ctlr *ctlr;
	Endpt *e;
	Endptx *x;
	int s, frnum;
	Usbhost *uh;