devtv.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

	dev = DEV(c->qid);
	switch (TYPE(c->qid)) {
	case Qdir:
		if (i == DEVDOTDOT) {
			mkqid(&qid, Qdir, 0, QTDIR);
			devdir(c, qid, "#V", 0, eve, 0555, dp);
			return 1;
		}

		if (i >= ntvs)
			return -1;
	
		mkqid(&qid, QID(i, Qsubdir), 0, QTDIR);
		snprint(up->genbuf, sizeof(up->genbuf), "tv%d", i);
		devdir(c, qid, up->genbuf, 0, eve, 0555, dp);
		return 1;

	case Qsubdir:
		if (i == DEVDOTDOT) {
			mkqid(&qid, QID(dev, Qdir), 0, QTDIR);
			snprint(up->genbuf, sizeof(up->genbuf), "tv%d", dev);
			devdir(c, qid, up->genbuf, 0, eve, 0555, dp);
			return 1;
		}
		
		return tv1gen(c, i + Qsubbase, dp);
	
	case Qvdata:
	case Qadata:
	case Qctl:
	case Qregs:
		return tv1gen(c, TYPE(c->qid), dp);

	default:
		return -1;
	}
}

static Walkqid *
tvwalk(Chan *c, Chan *nc, char **name, int nname)
{
	return devwalk(c, nc, name, nname, 0, 0, tvgen);
}

static int
tvstat(Chan *c, uchar *db, int n)
{
	return devstat(c, db, n, 0, 0, tvgen);
}

static Chan*
tvopen(Chan *c, int omode)
{
	if (omode != OREAD && 
		TYPE(c->qid) != Qctl && TYPE(c->qid) != Qvdata)
		error(Eperm);

	switch (TYPE(c->qid)) {
	case Qdir:
		return devopen(c, omode, nil, 0, tvgen);
	case Qadata:
		if (tvs[DEV(c->qid)].bt878 == nil)
			error(Enonexist);
		break;
	}

	c->mode = openmode(omode);
	c->flag |= COPEN;
	c->offset = 0;

	if (TYPE(c->qid) == Qadata)
		c->aux = nil;
	return c;
}

static void
tvclose(Chan *)
{}

static int
audioblock(void *)
{
	return 1;
}
	
static long
tvread(Chan *c, void *a, long n, vlong offset)
{
	static char regs[10 * K];
	static int regslen;
	Tv *tv;
	char *e, *p;
	uchar *src;

	USED(offset);

	switch(TYPE(c->qid)) {
	case Qdir:
	case Qsubdir:
		return devdirread(c, a, n, 0, 0, tvgen);

	case Qvdata: {
		int bpf, nb;

		tv = &tvs[DEV(c->qid)];
		bpf = ntsc_hactive * ntsc_vactive * getbitspp(tv) / 8;

		if (offset >= bpf) 
			return 0;

		nb = n;
		if (offset + nb > bpf)
			nb = bpf - offset;

		ilock(tv);
		if (tv->frames == nil || tv->lvframe >= tv->nframes ||
			tv->frames[tv->lvframe].fbase == nil) {
			iunlock(tv);
			return 0;
		}

		src = tv->frames[tv->lvframe].fbase;
		incref(&tv->fref);
		iunlock(tv);

		memmove(a, src + offset, nb);
		decref(&tv->fref);
		return nb;
	}

	case Qadata: {
		ulong uablock = (ulong)c->aux, bnum, tvablock;
		int boffs, nbytes;

		tv = &tvs[DEV(c->qid)];
		if (tv->bt878 == nil)
			error("#V: No audio device");
		if (tv->absize == 0)
			error("#V: audio not initialized");

		bnum = offset / tv->absize;
		boffs = offset % tv->absize;
		nbytes = tv->absize - boffs;

		incref(&tv->aref);
		while (1) {
			tvablock = tv->narblocks;	// Current tv block.

			if (uablock == 0)
				uablock = tvablock - 1;

			if (tvablock >= uablock + bnum + tv->narblocks)
				uablock = tvablock - 1 - bnum;

			if (uablock + bnum == tvablock) {
				sleep(tv, audioblock, nil);
				continue;
			}
			break;
		}

		print("uablock %ld, bnum %ld, boffs %d, nbytes %d, tvablock %ld\n",
				uablock, bnum, boffs, nbytes, tvablock);
		src = tv->abuf + ((uablock + bnum) % tv->nablocks) * tv->absize;
		print("copying from %.8ulX (abuf %.8ulX), nbytes %d (block %ld.%ld)\n", 
				src + boffs, tv->abuf, nbytes, uablock, bnum);

		memmove(a, src + boffs, nbytes);
		decref(&tv->aref);
		
		uablock += (boffs + nbytes) % tv->absize;
		c->aux = (void*)uablock;

		return nbytes;
	}

	case Qctl: {
		char str[128];

		tv = &tvs[DEV(c->qid)];
		snprint(str, sizeof str, "%dx%dx%d %s channel %d %s\n", 
				ntsc_hactive, ntsc_vactive, getbitspp(tv),
				getcolormode(tv->cfmt), tv->channel,
				tv->ainfo);
		return readstr(offset, a, strlen(str) + 1, str);
	}
		
	case Qregs:
		if (offset == 0) {
			Bt848 *bt848;
			int i;

			tv = &tvs[DEV(c->qid)];
			bt848 = tv->bt848;

			e = regs + sizeof(regs);
			p = regs;
			for (i = 0; i < 0x300 >> 2; i++)
				p = seprint(p, e, "%.3X %.8ulX\n", i << 2, ((ulong *)bt848)[i]);
			if (tv->bt878) {
				bt848 = tv->bt878;

				for (i = 0; i < 0x300 >> 2; i++)
					p = seprint(p, e, "%.3X %.8ulX\n", 
							i << 2, ((ulong *)bt848)[i]);
			}
			
			regslen = p - regs;
		}

		if (offset >= regslen) 
			return 0;
		if (offset + n > regslen)
			n = regslen - offset;

		return readstr(offset, a, n, &regs[offset]);

	default:
		n = 0;
		break;
	}
	return n;
}

static long
tvwrite(Chan *c, void *a, long n, vlong)
{
	Cmdbuf *cb;
	Cmdtab *ct;
	Tv *tv;

	tv = &tvs[DEV(c->qid)];
	switch(TYPE(c->qid)) {
	case Qctl:
		cb = parsecmd(a, n);
		if(waserror()){
			free(cb);
			nexterror();
		}
		ct = lookupcmd(cb, tvctlmsg, nelem(tvctlmsg));
		switch (ct->index) {
		case CMvstart:
			vstart(tv, (int)strtol(cb->f[1], (char **)nil, 0), 
					ntsc_hactive, ntsc_vactive, ntsc_hactive);
			break;

		case CMastart:
			astart(tv, cb->f[1], (uint)strtol(cb->f[2], (char **)nil, 0),
					(uint)strtol(cb->f[3], (char **)nil, 0),
					(uint)strtol(cb->f[4], (char **)nil, 0));
			break;

		case CMastop:
			astop(tv);
			break;

		case CMvgastart:
			vgastart(tv, strtoul(cb->f[1], (char **)nil, 0),
					(int)strtoul(cb->f[2], (char **)nil, 0));
			break;

		case CMvstop:
			vstop(tv);
			break;

		case CMchannel:
			frequency(tv, (int)strtol(cb->f[1], (char **)nil, 0), 
				(int)strtol(cb->f[2], (char **)nil, 0));
			break;

		case CMcolormode:
			colormode(tv, cb->f[1]);
			break;

		case CMvolume:
			if (!tv->msp)
				error("#V: No volume control");

			mspvolume(tv, 0, (int)strtol(cb->f[1], (char **)nil, 0), 
						(int)strtol(cb->f[2], (char **)nil, 0));
			break;

		case CMmute:
			if (!tv->msp)
				error("#V: No volume control");

			mspvolume(tv, 1, 0, 0);
			break;
		}
		poperror();
		free(cb);
		break;

	default:
		error(Eio);
	}
	return n;
}

Dev tvdevtab = {
	'V',
	"tv",

	devreset,
	tvinit,
	devshutdown,
	tvattach,
	tvwalk,
	tvstat,
	tvopen,
	devcreate,
	tvclose,
	tvread,
	devbread,
	tvwrite,
	devbwrite,
	devremove,
	devwstat,
};

static void
tvinterrupt(Ureg *, Tv *tv)
{
	Bt848 *bt848 = tv->bt848,
		*bt878 = tv->bt878;

	while (1) {
		ulong vstat, astat;
		uchar fnum;

		vstat = bt848->intstat;
		fnum = (vstat >> intstat_riscstatshift) & 0xf;
		vstat &= bt848->intmask;

		if (bt878)
			astat = bt878->intstat & bt878->intmask;
		else
			astat = 0;

		if (vstat == 0 && astat == 0)
			break;

		if (astat)
		print("vstat %.8luX, astat %.8luX\n", vstat, astat);

		bt848->intstat = vstat;
		if (bt878)
			bt878->intstat = astat;

		if ((vstat & intstat_fmtchg) == intstat_fmtchg) {
			iprint("int: fmtchg\n");
			vstat &= ~intstat_fmtchg;
		}

		if ((vstat & intstat_vpress) == intstat_vpress) {
//			iprint("int: vpress\n");
			vstat &= ~intstat_vpress;
		}
		
		if ((vstat & intstat_vsync) == intstat_vsync) {
			vstat &= ~intstat_vsync;
		}

		if ((vstat & intstat_scerr) == intstat_scerr) {
			iprint("int: scerr\n");
			bt848->gpiodmactl &= 
				~(gpiodmactl_riscenable|gpiodmactl_fifoenable);
			bt848->gpiodmactl |= gpiodmactl_fifoenable;
			bt848->gpiodmactl |= gpiodmactl_riscenable;
			vstat &= ~intstat_scerr;
		}

		if ((vstat & intstat_risci) == intstat_risci) {
			tv->lvframe = fnum;
			vstat &= ~intstat_risci;
		}
			
		if ((vstat & intstat_ocerr) == intstat_ocerr) {
			iprint("int: ocerr\n");
			vstat &= ~intstat_ocerr;
		}

		if ((vstat & intstat_fbus) == intstat_fbus) {
			iprint("int: fbus\n");
			vstat &= ~intstat_fbus;
		}

		if (vstat)
			iprint("int: (v) ignored interrupts %.8ulX\n", vstat);

		if ((astat & intstat_risci) == intstat_risci) {
			tv->narblocks++;
			if ((tv->narblocks % 100) == 0)
				print("a");
			wakeup(tv);
			astat &= ~intstat_risci;
		}

		if ((astat & intstat_fdsr) == intstat_fdsr) {
			iprint("int: (a) fdsr\n");
			bt848->gpiodmactl &= 
				~(gpiodmactl_acapenable | 
					gpiodmactl_riscenable | gpiodmactl_fifoenable);
			astat &= ~intstat_fdsr;
		}
			
		if (astat)
			iprint("int: (a) ignored interrupts %.8ulX\n", astat);
	}
}

static int
i2cread(Tv *tv, uchar off, uchar *v)
{	
	Bt848 *bt848 = tv->bt848;
	ulong intstat;
	int i;

	bt848->intstat	= intstat_i2cdone;
	bt848->i2c = (off << 24) | tv->i2ccmd;

	intstat = -1;
	for (i = 0; i != 1000; i++) {
		if ((intstat = bt848->intstat) & intstat_i2cdone)
			break;
		microdelay(1000);
	}

	if (i == 1000) {
		print("i2cread: timeout\n");
		return 0;
	}

	if ((intstat & intstat_i2crack) == 0)
		return 0;

	*v = bt848->i2c >> 8;
	return 1;
}

static int
i2cwrite(Tv *tv, uchar addr, uchar sub, uchar data, int both)
{
	Bt848 *bt848 = tv->bt848;
	ulong intstat, d;
	int i;

	bt848->intstat	= intstat_i2cdone;
	d = (addr << 24) | (sub << 16) | tv->i2ccmd;
	if (both)
		d |= (data << 8) | i2c_bt848w3b;
	bt848->i2c = d;

	intstat = 0;
	for (i = 0; i != 1000; i++) {
		if ((intstat = bt848->intstat) & intstat_i2cdone)
			break;
		microdelay(1000);
	}

	if (i == i2c_timeout) {
		print("i2cwrite: timeout\n");
		return 0;
	}

	if ((intstat & intstat_i2crack) == 0)
		return 0;

	return 1;
}

static ulong *
riscpacked(ulong pa, int fnum, int w, int h, int stride, ulong **lastjmp)
{
	ulong *p, *pbase;
	int i;

	pbase = p = (ulong *)malloc((h + 6) * 2 * sizeof(ulong));
	assert(p);

	assert(w <= 0x7FF);

	*p++ = riscsync | riscsync_resync | riscsync_vre;
	*p++ = 0;

	*p++ = riscsync | riscsync_fm1;
	*p++ = 0;

	for (i = 0; i != h / 2; i++) {
		*p++ = riscwrite | w | riscwrite_sol | riscwrite_eol;
		*p++ = pa + i * 2 * stride;
	}

	*p++ = riscsync | riscsync_resync | riscsync_vro;
	*p++ = 0;

	*p++ = riscsync | riscsync_fm1;
	*p++ = 0;

	for (i = 0; i != h / 2; i++) {
		*p++ = riscwrite | w | riscwrite_sol | riscwrite_eol;
		*p++ = pa + (i * 2 + 1) * stride;
	}

	// reset status.  you really need two instructions ;-(.
	*p++ = riscjmp | (0xf << risclabelshift_reset); 	
	*p++ = PADDR(p);
	*p++ = riscjmp | riscirq | (fnum << risclabelshift_set);
	*lastjmp = p;

	return pbase;
}

static ulong *
riscplanar411(ulong pa, int fnum, int w, int h, ulong **lastjmp)
{
	ulong *p, *pbase, Cw, Yw, Ch;
	uchar *Ybase, *Cbbase, *Crbase;
	int i, bitspp;

	bitspp = 6;
	assert(w * bitspp / 8 <= 0x7FF);
	pbase = p = (ulong *)malloc((h + 6) * 5 * sizeof(ulong));
	assert(p);

	Yw = w;
	Ybase = (uchar *)pa;
	Cw = w >> 1;
	Ch = h >> 1;
	Cbbase = Ybase + Yw * h;
	Crbase = Cbbase + Cw * Ch;
 
	*p++ = riscsync | riscsync_resync | riscsync_vre;
	*p++ = 0;

	*p++ = riscsync | riscsync_fm3;
	*p++ = 0;

	for (i = 0; i != h / 2; i++) {
		*p++ = riscwrite123 | Yw | riscwrite_sol | riscwrite_eol;
		*p++ = (Cw << 16) | Cw;	
		*p++ = (ulong)(Ybase + i * 2 * Yw);
		*p++ = (ulong)(Cbbase + i * Cw);		// Do not interlace
		*p++ = (ulong)(Crbase + i * Cw);
	}

	*p++ = riscsync | riscsync_resync | riscsync_vro;
	*p++ = 0;

	*p++ = riscsync | riscsync_fm3;
	*p++ = 0;

	for (i = 0; i != h / 2; i++) {
		*p++ = riscwrite1s23 | Yw | riscwrite_sol | riscwrite_eol;
		*p++ = (Cw << 16) | Cw;	
		*p++ = (ulong)(Ybase + (i * 2 + 1) * Yw);
	}

	// reset status.  you really need two instructions ;-(.
	*p++ = riscjmp | (0xf << risclabelshift_reset); 	
	*p++ = PADDR(p);
	*p++ = riscjmp | riscirq | (fnum << risclabelshift_set);
	*lastjmp = p;

	return pbase;
}

static ulong *
riscplanar422(ulong pa, int fnum, int w, int h, ulong **lastjmp)
{
	ulong *p, *pbase, Cw, Yw;
	uchar *Ybase, *Cbbase, *Crbase;
	int i, bpp;

	bpp = 2;
	assert(w * bpp <= 0x7FF);
	pbase = p = (ulong *)malloc((h + 6) * 5 * sizeof(ulong));
	assert(p);

	Yw = w;
	Ybase = (uchar *)pa;
	Cw = w >> 1;
	Cbbase = Ybase + Yw * h;
	Crbase = Cbbase + Cw * h;

	*p++ = riscsync | riscsync_resync | riscsync_vre;
	*p++ = 0;

	*p++ = riscsync | riscsync_fm3;
	*p++ = 0;

	for (i = 0; i != h / 2; i++) {
		*p++ = riscwrite123 | Yw | riscwrite_sol | riscwrite_eol;
		*p++ = (Cw << 16) | Cw;	
		*p++ = (ulong)(Ybase + i * 2 * Yw);
		*p++ = (ulong)(Cbbase + i * 2 * Cw);
		*p++ = (ulong)(Crbase + i * 2 * Cw);
	}

	*p++ = riscsync | riscsync_resync | riscsync_vro;
	*p++ = 0;

	*p++ = riscsync | riscsync_fm3;
	*p++ = 0;

	for (i = 0; i != h / 2; i++) {
		*p++ = riscwrite123 | Yw | riscwrite_sol | riscwrite_eol;
		*p++ = (Cw << 16) | Cw;	
		*p++ = (ulong)(Ybase + (i * 2 + 1) * Yw);
		*p++ = (ulong)(Cbbase + (i * 2 + 1) * Cw);
		*p++ = (ulong)(Crbase + (i * 2 + 1) * Cw);
	}

	// reset status.  you really need two instructions ;-(.
	*p++ = riscjmp | (0xf << risclabelshift_reset); 	
	*p++ = PADDR(p);
	*p++ = riscjmp | riscirq | (fnum << risclabelshift_set);
	*lastjmp = p;

	return pbase;
}

static ulong *
riscaudio(ulong pa, int nblocks, int bsize)
{
	ulong *p, *pbase;
	int i;

	pbase = p = (ulong *)malloc((nblocks + 3) * 2 * sizeof(ulong));
	assert(p);

	*p++ = riscsync|riscsync_fm1;
	*p++ = 0;
	
	for (i = 0; i != nblocks; i++) {
		*p++ = riscwrite | riscwrite_sol | riscwrite_eol | bsize | riscirq |
				((i & 0xf) << risclabelshift_set) | 
				((~i & 0xf) << risclabelshift_reset);
		*p++ = pa + i * bsize;
	}

	*p++ = riscsync | riscsync_vro;
	*p++ = 0;
	*p++ = riscjmp;
	*p++ = PADDR(pbase);
	USED(p);

	return pbase;
}


static void
vactivate(Tv *tv, Frame *frames, int nframes)
{
	Bt848 *bt848 = tv->bt848;

	ilock(tv);
	if (tv->frames) {
		iunlock(tv);
		error(Einuse);
	}
	poperror();

	tv->frames = frames;
	tv->nframes = nframes;

	bt848->riscstrtadd = PADDR(tv->frames[0].fstart);
	bt848->capctl |= capctl_captureodd|capctl_captureeven;
	bt848->gpiodmactl |= gpiodmactl_fifoenable;
	bt848->gpiodmactl |= gpiodmactl_riscenable;
	
	iunlock(tv);
}

static void
vstart(Tv *tv, int nframes, int w, int h, int stride)
{
	Frame *frames;
	int bitspp, i, bpf;

	if (nframes >= 0x10)
		error(Ebadarg);

	bitspp = getbitspp(tv);
	bpf = w * h * bitspp / 8;

	// Add one as a spare.
	frames = (Frame *)malloc(nframes * sizeof(Frame));
	assert(frames);
	if (waserror()) {
		for (i = 0; i != nframes; i++)
			if (frames[i].fbase)
				free(frames[i].fbase);
		free(frames);
		nexterror();
	}
	memset(frames, 0, nframes * sizeof(Frame));

	for (i = 0; i != nframes; i++) {
		if ((frames[i].fbase = (uchar *)malloc(bpf)) == nil)
			error(Enomem);
		
		switch (tv->cfmt) {
		case colorfmt_YCbCr422:
			frames[i].fstart = riscplanar422(PADDR(frames[i].fbase), i, 
									 w, h, &frames[i].fjmp);
			break;
		case colorfmt_YCbCr411:
			frames[i].fstart = riscplanar411(PADDR(frames[i].fbase), i, 
									 w, h, &frames[i].fjmp);
			break;
		case colorfmt_rgb16:
			frames[i].fstart = riscpacked(PADDR(frames[i].fbase), i, 
								     w * bitspp / 8, h, stride * bitspp / 8, 
								     &frames[i].fjmp);
			break;
		default:
			panic("vstart: Unsupport colorformat\n");
		}
	}

	for (i = 0; i != nframes; i++)
		*frames[i].fjmp = 
			PADDR((i == nframes - 1)? frames[0].fstart: frames[i + 1].fstart);

	vactivate(tv, frames, nframes);
}

static void
astart(Tv *tv, char *input, uint rate, uint nab, uint nasz)
{
	Bt848 *bt878 = tv->bt878;
	ulong *arisc;
	int selector;