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Message-Id: <50c1a92978c503051edfe64339441a0b53dd3fb4.1668828454.git.mforney@mforney.org>
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From: Michael Forney <mforney@mforney.org>
Date: Fri, 18 Nov 2022 20:35:33 +0000
To: 9front@9front.org
Subject: [9front] [PATCH 5/5] nusb/audio: add support for USB audio 2.0
Reply-To: 9front@9front.org
Precedence: bulk

USB audio 2.0 mandates the use of an interface association descriptor
to group together the interfaces that comprise an audio function, and
the AudioControl interface no longer lists the streams. So for 2.0
devices, find and use the IAD to enumerate the streams.

Additionally, we now need to locate the terminal associated with the
stream, and the clock for that terminal. This replaces the frequency
fields in the type I format type descriptor, and the sampling rate is
now set with a request directed at the clock entity in the control
interface, rather than the endpoint.
---
 sys/src/cmd/nusb/audio/audio.c | 258 +++++++++++++++++++++++++++++----
 1 file changed, 228 insertions(+), 30 deletions(-)

diff --git a/sys/src/cmd/nusb/audio/audio.c b/sys/src/cmd/nusb/audio/audio.c
index 2cd75f6361..195bd6bd5b 100644
--- a/sys/src/cmd/nusb/audio/audio.c
+++ b/sys/src/cmd/nusb/audio/audio.c
@@ -6,14 +6,17 @@
 #include "usb.h"
 
 enum {
-	Rgetcur	= 0x81,
-	Rgetmin	= 0x82,
-	Rgetmax	= 0x83,
-	Rgetres	= 0x84,
+	Paudio1 = 0x00,
+	Paudio2 = 0x20,
+
+	Csamfreq = 0x01,
+
+	/* audio 1 */
 	Rsetcur	= 0x01,
-	Rsetmin	= 0x02,
-	Rsetmax	= 0x03,
-	Rsetres	= 0x04,
+
+	/* audio 2 */
+	Rcur = 0x01,
+	Rrange = 0x02,
 };
 
 typedef struct Range Range;
@@ -31,9 +34,15 @@ struct Aconf
 	int	bps;	/* subslot size (bytes per sample) */
 	int	format;
 	int	channels;
-	int	controls;
+	int	terminal;
 	Range	*freq;
 	int	nfreq;
+
+	/* audio 1 */
+	int	controls;
+
+	/* audio 2 */
+	int	clock;
 };
 
 int audiodelay = 1764;	/* 40 ms */
@@ -64,6 +73,24 @@ findiface(Conf *conf, int class, int subclass, int id)
 	return nil;
 }
 
+Desc*
+findiad(Usbdev *u, int id, int csp)
+{
+	int i;
+	Desc *dd;
+	uchar *b;
+
+	for(i = 0; i < nelem(u->ddesc); i++){
+		dd = u->ddesc[i];
+		if(dd == nil || dd->data.bDescriptorType != 11 || dd->data.bLength != 8)
+			continue;
+		b = dd->data.bbytes;
+		if(b[0] == id && b[0]+b[1] <= Niface && csp == CSP(b[2], b[3], b[4]))
+			return dd;
+	}
+	return nil;
+}
+
 Desc*
 findacheader(Usbdev *u, Iface *ac)
 {
@@ -78,14 +105,70 @@ findacheader(Usbdev *u, Iface *ac)
 		if(dd->data.bLength < 8 || dd->data.bbytes[0] != 1)
 			continue;
 		b = dd->data.bbytes;
-		if(dd->data.bLength == 8+b[5])
+		switch(Proto(ac->csp)){
+		case Paudio1:
+			if(dd->data.bLength == 8+b[5])
+				return dd;
+			break;
+		case Paudio2:
+			if(dd->data.bLength == 9)
+				return dd;
+			break;
+		}
+	}
+	return nil;
+}
+
+Desc*
+findterminal(Usbdev *u, Iface *ac, int id)
+{
+	Desc *dd;
+	uchar *b;
+	int i;
+
+	for(i = 0; i < nelem(u->ddesc); i++){
+		dd = u->ddesc[i];
+		if(dd == nil || dd->iface != ac)
+			continue;
+		if(dd->data.bDescriptorType != 0x24 || dd->data.bLength < 4)
+			continue;
+		b = dd->data.bbytes;
+		if(b[1] != id)
+			continue;
+		/* check descriptor length according to type and proto */
+		switch(b[0]<<16 | dd->data.bLength<<8 | Proto(ac->csp)){
+		case 0x020C00|Paudio1:
+		case 0x030900|Paudio1:
+		case 0x021100|Paudio2:
+		case 0x030c00|Paudio2:
+			return dd;
+		}
+	}
+	return nil;
+}
+
+Desc*
+findclocksource(Usbdev *u, Iface *ac, int id)
+{
+	Desc *dd;
+	uchar *b;
+	int i;
+
+	for(i = 0; i < nelem(u->ddesc); i++){
+		dd = u->ddesc[i];
+		if(dd == nil || dd->iface != ac)
+			continue;
+		if(dd->data.bDescriptorType != 0x24 || dd->data.bLength != 8)
+			continue;
+		b = dd->data.bbytes;
+		if(b[0] == 0x0A && b[1] == id)
 			return dd;
 	}
 	return nil;
 }
 
 void
-parseasdesc(Desc *dd, Aconf *c)
+parseasdesc1(Desc *dd, Aconf *c)
 {
 	uchar *b;
 	Range *f;
@@ -101,6 +184,7 @@ parseasdesc(Desc *dd, Aconf *c)
 	case 0x2401:	/* CS_INTERFACE, AS_GENERAL */
 		if(dd->data.bLength != 7)
 			return;
+		c->terminal = b[1];
 		c->format = GET2(&b[3]);
 		break;
 
@@ -129,12 +213,82 @@ parseasdesc(Desc *dd, Aconf *c)
 }
 
 void
-parsestream(Dev *d, int id)
+parseasdesc2(Desc *dd, Aconf *c)
+{
+	uchar *b;
+
+	b = dd->data.bbytes;
+	switch(dd->data.bDescriptorType<<8 | b[0]){
+	case 0x2401:	/* CS_INTERFACE, AS_GENERAL */
+		if(dd->data.bLength != 16 || b[3] != 1)
+			return;
+		c->terminal = b[1];
+		c->format = GET4(&b[4]);
+		c->channels = b[8];
+		break;
+
+	case 0x2402:	/* CS_INTERFACE, FORMAT_TYPE */
+		if(dd->data.bLength != 6 || b[1] != 1)
+			return;
+		c->bps = b[2];
+		c->bits = b[3];
+		break;
+	}
+}
+
+int
+setclock(Dev *d, Iface *ac, Aconf *c, int speed)
+{
+	uchar b[4];
+	int index;
+
+	switch(Proto(ac->csp)){
+	case Paudio1:
+		if((c->controls & 1) == 0)
+			break;
+		b[0] = speed;
+		b[1] = speed >> 8;
+		b[2] = speed >> 16;
+		index = c->ep->id & Epmax;
+		if(c->ep->dir == Ein)
+			index |= 0x80;
+		return usbcmd(d, Rh2d|Rclass|Rep, Rsetcur, Csamfreq<<8, index, b, 3);
+	case Paudio2:
+		PUT4(b, speed);
+		index = c->clock<<8 | ac->id;
+		return usbcmd(d, Rh2d|Rclass|Riface, Rcur, Csamfreq<<8, index, b, 4);
+	}
+	return 0;
+}
+
+int
+getclockrange(Dev *d, Iface *ac, Aconf *c)
+{
+	uchar b[2 + 32*12];
+	int i, n, rc;
+
+	rc = usbcmd(d, Rd2h|Rclass|Riface, Rrange, Csamfreq<<8, c->clock<<8 | ac->id, b, sizeof(b));
+	if(rc < 0)
+		return -1;
+	if(rc < 2 || rc < 2 + (n = GET2(b))*12){
+		werrstr("invalid response");
+		return -1;
+	}
+	c->freq = emallocz(n, sizeof(Range));
+	c->nfreq = n;
+	for(i = 0; i < n; i++)
+		c->freq[i] = (Range){GET4(&b[2 + i*12]), GET4(&b[6 + i*12])};
+	return 0;
+}
+
+void
+parsestream(Dev *d, Iface *ac, int id)
 {
 	Iface *as;
 	Desc *dd;
 	Ep *e;
 	Aconf *c;
+	uchar *b;
 	int i;
 
 	/* find AS interface */
@@ -154,6 +308,7 @@ parsestream(Dev *d, int id)
 			}
 		}
 		if(c->ep == nil){
+		Skip:
 			free(c);
 			as->aux = nil;
 			continue;
@@ -164,13 +319,48 @@ parsestream(Dev *d, int id)
 			dd = d->usb->ddesc[i];
 			if(dd == nil || dd->iface != as)
 				continue;
-			parseasdesc(dd, c);
+			switch(Proto(ac->csp)){
+			case Paudio1:
+				parseasdesc1(dd, c);
+				break;
+			case Paudio2:
+				parseasdesc2(dd, c);
+				break;
+			}
+		}
+
+		if(Proto(ac->csp) == Paudio1)
+			continue;
+
+		dd = findterminal(d->usb, ac, c->terminal);
+		if(dd == nil)
+			goto Skip;
+		b = dd->data.bbytes;
+		switch(b[0]){
+		case 0x02:	/* INPUT_TERMINAL */
+			c->clock = b[5];
+			break;
+		case 0x03:	/* OUTPUT_TERMINAL */
+			c->clock = b[6];
+			break;
+		}
+
+		dd = findclocksource(d->usb, ac, c->clock);
+		if(dd == nil)
+			goto Skip;
+		b = dd->data.bbytes;
+		/* check that clock has rw frequency control */
+		if((b[3] & 3) != 3)
+			goto Skip;
+		if(getclockrange(d, ac, c) != 0){
+			fprint(2, "getclockrange %d: %r", c->clock);
+			goto Skip;
 		}
 	}
 }
 
 Dev*
-setupep(Dev *d, Ep *e, int speed)
+setupep(Dev *d, Iface *ac, Ep *e, int speed)
 {
 	int dir = e->dir;
 	Aconf *c;
@@ -192,15 +382,9 @@ setupep(Dev *d, Ep *e, int speed)
 Foundaltc:
 	if(setalt(d, e->iface) < 0)
 		return nil;
-
-	if(c->controls & 1){
-		uchar b[4];
-
-		b[0] = speed;
-		b[1] = speed >> 8;
-		b[2] = speed >> 16;
-		if(usbcmd(d, Rh2d|Rclass|Rep, Rsetcur, 0x100, (e->dir==Ein?0x80:0)|(e->id&Epmax), b, 3) < 0)
-			fprint(2, "warning: set freq: %r\n");
+	if(setclock(d, ac, c, speed) < 0){
+		werrstr("setclock: %r");
+		return nil;
 	}
 
 	if((d = openep(d, e)) == nil){
@@ -246,13 +430,13 @@ fswrite(Req *r)
 
 		speed = atoi(f[1]);
 Setup:
-		if((d = setupep(audiodev, audioepout, speed)) == nil){
+		if((d = setupep(audiodev, audiocontrol, audioepout, speed)) == nil){
 			responderror(r);
 			return;
 		}
 		closedev(d);
 		if(audioepin != nil)
-			if(d = setupep(audiodev, audioepin, speed))
+			if(d = setupep(audiodev, audiocontrol, audioepin, speed))
 				closedev(d);
 		audiofreq = speed;
 	} else if(strcmp(f[0], "delay") == 0){
@@ -286,6 +470,7 @@ main(int argc, char *argv[])
 	Iface *ac;
 	Aconf *c;
 	Ep *e;
+	uchar *b;
 	int i;
 
 	ARGBEGIN {
@@ -310,11 +495,24 @@ main(int argc, char *argv[])
 		sysfatal("no audio control interface");
 	audiocontrol = ac;
 
-	dd = findacheader(d->usb, ac);
-	if(dd == nil)
-		sysfatal("no audio control header");
-	for(i = 6; i < dd->data.bLength-2; i++)
-		parsestream(d, dd->data.bbytes[i]);
+	switch(Proto(ac->csp)){
+	case Paudio1:
+		dd = findacheader(d->usb, ac);
+		if(dd == nil)
+			sysfatal("no audio control header");
+		b = dd->data.bbytes;
+		for(i = 6; i < dd->data.bLength-2; i++)
+			parsestream(d, ac, b[i]);
+		break;
+	case Paudio2:
+		dd = findiad(d->usb, ac->id, CSP(Claudio, 0, Paudio2));
+		if(dd == nil)
+			sysfatal("no audio function");
+		b = dd->data.bbytes;
+		for(i = b[0]+1; i < b[0]+b[1]; i++)
+			parsestream(d, ac, i);
+		break;
+	}
 
 	for(i = 0; i < nelem(d->usb->ep); i++){
 		for(e = d->usb->ep[i]; e != nil; e = e->next){
@@ -336,7 +534,7 @@ main(int argc, char *argv[])
 			audioepout = e;
 			break;
 		}
-		if((ed = setupep(audiodev, e, audiofreq)) == nil){
+		if((ed = setupep(d, ac, e, audiofreq)) == nil){
 			fprint(2, "setupep: %r\n");
 
 			if(e == audioepin)
-- 
2.37.3