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

#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"io.h"
#include	"../port/error.h"

#include	"usb.h"

#define XPRINT if(debug)print
#define XXPRINT if(0)print

static int Chatty = 0;
static int debug = 0;

static	char	Estalled[] = "usb endpoint stalled";

/*
 * UHCI interface registers and bits
 */
enum
{
	/* i/o space */
	Cmd = 0,
	Status = 2,
	Usbintr = 4,
	Frnum = 6,
	Flbaseadd = 8,
	SOFMod = 0xC,
	Portsc0 = 0x10,
	Portsc1 = 0x12,

	/* port status */
	Suspend =	1<<12,
	PortReset =	1<<9,
	SlowDevice =	1<<8,
	ResumeDetect =	1<<6,
	PortChange =	1<<3,	/* write 1 to clear */
	PortEnable =	1<<2,
	StatusChange =	1<<1,	/* write 1 to clear */
	DevicePresent =	1<<0,

	NFRAME = 	1024,
	FRAMESIZE=	NFRAME*sizeof(ulong),	/* fixed by hardware; aligned to same */

	Vf =		1<<2,	/* TD only */
	IsQH =		1<<1,
	Terminate =	1<<0,

	/* TD.status */
	SPD =		1<<29,
	ErrLimit0 =	0<<27,
	ErrLimit1 =	1<<27,
	ErrLimit2 =	2<<27,
	ErrLimit3 =	3<<27,
	LowSpeed =	1<<26,
	IsoSelect =	1<<25,
	IOC =		1<<24,
	Active =	1<<23,
	Stalled =	1<<22,
	DataBufferErr =	1<<21,
	Babbling =	1<<20,
	NAKed =		1<<19,
	CRCorTimeout =	1<<18,
	BitstuffErr =	1<<17,
	AnyError = (Stalled | DataBufferErr | Babbling | NAKed | CRCorTimeout | BitstuffErr),

	/* TD.dev */
	IsDATA1 =	1<<19,

	/* TD.flags (software) */
	CancelTD=	1<<0,
	IsoClean=	1<<2,
};

static struct
{
	int	bit;
	char	*name;
}
portstatus[] =
{
	{ Suspend,		"suspend", },
	{ PortReset,		"reset", },
	{ SlowDevice,		"lowspeed", },
	{ ResumeDetect,		"resume", },
	{ PortChange,		"portchange", },
	{ PortEnable,		"enable", },
	{ StatusChange,		"statuschange", },
	{ DevicePresent,	"present", },
};

typedef struct Ctlr Ctlr;
typedef struct Endptx Endptx;
typedef struct QH QH;
typedef struct TD TD;

/*
 * software structures
 */
struct Ctlr
{
	Lock;	/* protects state shared with interrupt (eg, free list) */
	Ctlr*	next;
	Pcidev*	pcidev;
	int	active;

	int	io;
	ulong*	frames;	/* frame list */
	ulong*	frameld;	/* real time load on each of the frame list entries */
	QLock	resetl;	/* lock controller during USB reset */

	TD*	tdpool;
	TD*	freetd;
	QH*	qhpool;
	QH*	freeqh;

	QH*	ctlq;	/* queue for control i/o */
	QH*	bwsop;	/* empty bandwidth sop (to PIIX4 errata specifications) */
	QH*	bulkq;	/* queue for bulk i/o (points back to bandwidth sop) */
	QH*	recvq;	/* receive queues for bulk i/o */

	Udev*	ports[2];

	struct {
		Lock;
		Endpt*	f;
	} activends;

	long	usbints;	/* debugging */
	long	framenumber;
	long	frameptr;
	long	usbbogus;
};

#define	IN(x)		ins(ctlr->io+(x))
#define	OUT(x, v)	outs(ctlr->io+(x), (v))

static Ctlr* ctlrhead;
static Ctlr* ctlrtail;

struct Endptx
{
	QH*	epq;		/* queue of TDs for this endpoint */

	/* ISO related: */
	void*	tdalloc;
	void*	bpalloc;
	uchar*	bp0;		/* first block in array */
	TD*	td0;		/* first td in array */
	TD*	etd;		/* pointer into circular list of TDs for isochronous ept */
	TD*	xtd;		/* next td to be cleaned */
};

/*
 * UHCI hardware structures, aligned on 16-byte boundary
 */
struct TD
{
	ulong	link;
	ulong	status;	/* controller r/w */
	ulong	dev;
	ulong	buffer;

	/* software */
	ulong	flags;
	union{
		Block*	bp;	/* non-iso */
		ulong	offset;	/* iso */
	};
	Endpt*	ep;
	TD*	next;
};
#define	TFOL(p)	((TD*)KADDR((ulong)(p) & ~(0xF|PCIWINDOW)))

struct QH
{
	ulong	head;
	ulong	entries;	/* address of next TD or QH to process (updated by controller) */

	/* software */
	QH*	hlink;
	TD*	first;
	QH*	next;		/* free list */
	TD*	last;
	ulong	_d1;		/* fillers */
	ulong	_d2;
};
#define	QFOL(p)	((QH*)KADDR((ulong)(p) & ~(0xF|PCIWINDOW)))

static TD *
alloctd(Ctlr *ctlr)
{
	TD *t;

	ilock(ctlr);
	t = ctlr->freetd;
	if(t == nil)
		panic("alloctd");	/* TO DO */
	ctlr->freetd = t->next;
	t->next = nil;
	iunlock(ctlr);
	t->ep = nil;
	t->bp = nil;
	t->status = 0;
	t->link = Terminate;
	t->buffer = 0;
	t->flags = 0;
	return t;
}

static void
freetd(Ctlr *ctlr, TD *t)
{
	t->ep = nil;
	if(t->bp)
		freeb(t->bp);
	t->bp = nil;
	ilock(ctlr);
	t->buffer = 0xdeadbeef;
	t->next = ctlr->freetd;
	ctlr->freetd = t;
	iunlock(ctlr);
}

static void
dumpdata(Block *b, int n)
{
	int i;

	XPRINT("\tb %8.8lux[%d]: ", (ulong)b->rp, n);
	if(n > 16)
		n = 16;
	for(i=0; i<n; i++)
		XPRINT(" %2.2ux", b->rp[i]);
	XPRINT("\n");
}

static void
dumptd(TD *t, int follow)
{
	int i, n;
	char buf[20], *s;
	TD *t0;

	t0 = t;
	while(t){
		i = t->dev & 0xFF;
		if(i == TokOUT || i == TokSETUP)
			n = ((t->dev>>21) + 1) & 0x7FF;
		else if((t->status & Active) == 0)
			n = (t->status + 1) & 0x7FF;
		else
			n = 0;
		s = buf;
		if(t->status & Active)
			*s++ = 'A';
		if(t->status & Stalled)
			*s++ = 'S';
		if(t->status & DataBufferErr)
			*s++ = 'D';
		if(t->status & Babbling)
			*s++ = 'B';
		if(t->status & NAKed)
			*s++ = 'N';
		if(t->status & CRCorTimeout)
			*s++ = 'T';
		if(t->status & BitstuffErr)
			*s++ = 'b';
		if(t->status & LowSpeed)
			*s++ = 'L';
		*s = 0;
		XPRINT("td %8.8lux: ", t);
		XPRINT("l=%8.8lux s=%8.8lux d=%8.8lux b=%8.8lux %8.8lux f=%8.8lux\n",
			t->link, t->status, t->dev, t->buffer, t->bp?(ulong)t->bp->rp:0, t->flags);
		XPRINT("\ts=%s,ep=%ld,d=%ld,D=%ld\n",
			buf, (t->dev>>15)&0xF, (t->dev>>8)&0xFF, (t->dev>>19)&1);
		if(debug && t->bp && (t->flags & CancelTD) == 0)
			dumpdata(t->bp, n);
		if(!follow || t->link & Terminate || t->link & IsQH)
			break;
		t = TFOL(t->link);
		if(t == t0)
			break;	/* looped */
	}
}

static TD *
alloctde(Ctlr *ctlr, Endpt *e, int pid, int n)
{
	TD *t;
	int tog, id;

	t = alloctd(ctlr);
	id = (e->x<<7)|(e->dev->x&0x7F);
	tog = 0;
	if((pid == TokOUT && e->wdata01) || (pid == TokIN && e->rdata01))
		tog = IsDATA1;
	t->ep = e;
	t->status = ErrLimit3 | Active | IOC;	/* or put IOC only on last? */
	if(e->dev->ls)
		t->status |= LowSpeed;
	t->dev = ((n-1)<<21) | ((id&0x7FF)<<8) | pid | tog;
	return t;
}

static QH *
allocqh(Ctlr *ctlr)
{
	QH *qh;

	ilock(ctlr);
	qh = ctlr->freeqh;
	if(qh == nil)
		panic("allocqh");	/* TO DO */
	ctlr->freeqh = qh->next;
	qh->next = nil;
	iunlock(ctlr);
	qh->head = Terminate;
	qh->entries = Terminate;
	qh->hlink = nil;
	qh->first = nil;
	qh->last = nil;
	return qh;
}

static void
freeqh(Ctlr *ctlr, QH *qh)
{
	ilock(ctlr);
	qh->next = ctlr->freeqh;
	ctlr->freeqh = qh;
	iunlock(ctlr);
}

static void
dumpqh(QH *q)
{
	int i;
	QH *q0;

	q0 = q;
	for(i = 0; q != nil && i < 10; i++){
		XPRINT("qh %8.8lux: %8.8lux %8.8lux\n", q, q->head, q->entries);
		if((q->entries & (IsQH|Terminate)) == 0)
			dumptd(TFOL(q->entries), 1);
		if(q->head & Terminate)
			break;
		if((q->head & IsQH) == 0){
			XPRINT("head:");
			dumptd(TFOL(q->head), 1);
			break;
		}
		q = QFOL(q->head);
		if(q == q0)
			break;	/* looped */
	}
}

static void
queuetd(Ctlr *ctlr, QH *q, TD *t, int vf, char *why)
{
	TD *lt;

	for(lt = t; lt->next != nil; lt = lt->next)
		lt->link = PCIWADDR(lt->next) | vf;
	lt->link = Terminate;
	ilock(ctlr);
	XPRINT("queuetd %s: t=%p lt=%p q=%p first=%p last=%p entries=%.8lux\n",
		why, t, lt, q, q->first, q->last, q->entries);
	if(q->first != nil){
		q->last->link = PCIWADDR(t) | vf;
		q->last->next = t;
	}else{
		q->first = t;
		q->entries = PCIWADDR(t);
	}
	q->last = lt;
	XPRINT("	t=%p q=%p first=%p last=%p entries=%.8lux\n",
		t, q, q->first, q->last, q->entries);
	dumpqh(q);
	iunlock(ctlr);
}

static void
cleantd(Ctlr *ctlr, TD *t, int discard)
{
	Block *b;
	int n, err;

	XPRINT("cleanTD: %8.8lux %8.8lux %8.8lux %8.8lux\n", t->link, t->status, t->dev, t->buffer);
	if(t->ep != nil && t->ep->debug)
		dumptd(t, 0);
	if(t->status & Active)
		panic("cleantd Active");
	err = t->status & (AnyError&~NAKed);
	/* TO DO: on t->status&AnyError, q->entries will not have advanced */
	if (err) {
		XPRINT("cleanTD: Error %8.8lux %8.8lux %8.8lux %8.8lux\n", t->link, t->status, t->dev, t->buffer);
//		print("cleanTD: Error %8.8lux %8.8lux %8.8lux %8.8lux\n", t->link, t->status, t->dev, t->buffer);
	}
	switch(t->dev&0xFF){
	case TokIN:
		if(discard || (t->flags & CancelTD) || t->ep == nil || t->ep->x!=0&&err){
			if(t->ep != nil){
				if(err != 0)
					t->ep->err = err==Stalled? Estalled: Eio;
				wakeup(&t->ep->rr);	/* in case anyone cares */
			}
			break;
		}
		b = t->bp;
		n = (t->status + 1) & 0x7FF;
		if(n > b->lim - b->wp)
			n = 0;
		b->wp += n;
		if(Chatty)
			dumpdata(b, n);
		t->bp = nil;
		t->ep->nbytes += n;
		t->ep->nblocks++;
		qpass(t->ep->rq, b);	/* TO DO: flow control */
		wakeup(&t->ep->rr);	/* TO DO */
		break;
	case TokSETUP:
		XPRINT("cleanTD: TokSETUP %lux\n", &t->ep);
		/* don't really need to wakeup: subsequent IN or OUT gives status */
		if(t->ep != nil) {
			wakeup(&t->ep->wr);	/* TO DO */
			XPRINT("cleanTD: wakeup %lux\n", &t->ep->wr);
		}
		break;
	case TokOUT:
		/* TO DO: mark it done somewhere */
		XPRINT("cleanTD: TokOut %lux\n", &t->ep);
		if(t->ep != nil){
			if(t->bp){
				n = BLEN(t->bp);
				t->ep->nbytes += n;
				t->ep->nblocks++;
			}
			if(t->ep->x!=0 && err != 0)
				t->ep->err = err==Stalled? Estalled: Eio;
			if(--t->ep->ntd < 0)
				panic("cleantd ntd");
			wakeup(&t->ep->wr);	/* TO DO */
			XPRINT("cleanTD: wakeup %lux\n", &t->ep->wr);
		}
		break;
	}
	freetd(ctlr, t);
}

static void
cleanq(Ctlr *ctlr, QH *q, int discard, int vf)
{
	TD *t, *tp;

	ilock(ctlr);
	tp = nil;
	for(t = q->first; t != nil;){
		XPRINT("cleanq: %8.8lux %8.8lux %8.8lux %8.8lux %8.8lux %8.8lux\n", t->link, t->status, t->dev, t->buffer, t->flags, t->next);
		if(t->status & Active){
			if(t->status & NAKed){
				t->status = (t->status & ~NAKed) | IOC;	/* ensure interrupt next frame */
				tp = t;
				t = t->next;
				continue;
			}
			if(t->flags & CancelTD){
				XPRINT("cancelTD: %8.8lux\n", (ulong)t);
				t->status = (t->status & ~Active) | IOC;	/* ensure interrupt next frame */
				tp = t;
				t = t->next;
				continue;
			}
			tp = t;
			t = t->next;
			continue;
		}
		t->status &= ~IOC;
		if (tp == nil) {
			q->first = t->next;
			if(q->first != nil)
				q->entries = PCIWADDR(q->first);
			else
				q->entries = Terminate;
		} else {
			tp->next = t->next;
			if (t->next != nil)
				tp->link = PCIWADDR(t->next) | vf;
			else
				tp->link = Terminate;
		}
		if (q->last == t)
			q->last = tp;
		iunlock(ctlr);
		cleantd(ctlr, t, discard);
		ilock(ctlr);
		if (tp)
			t = tp->next;
		else
			t = q->first;
		XPRINT("t = %8.8lux\n", t);
		dumpqh(q);
	}
	if(q->first && q->entries != PCIWADDR(q->first)){
		ctlr->usbbogus++;
		q->entries = PCIWADDR(q->first);
	}
	iunlock(ctlr);
}