nusb: simple playback only audio driver

sys/src/cmd/nusb/audio/audio.c

@@ -0,0 +1,118 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include "usb.h"
+
+int audiofreq = 44100;
+int audiochan = 2;
+int audiores = 16;
+
+char validaltc[] = "";
+
+void
+parsedescr(Desc *dd)
+{
+	uchar *b;
+	int i;
+
+	if(dd == nil || dd->iface == nil || dd->altc == nil)
+		return;
+	b = (uchar*)&dd->data;
+	if(Subclass(dd->iface->csp) != 2 || b[1] != 0x24 || b[2] != 0x02)
+		return;
+	if(b[4] != audiochan)
+		return;
+	if(b[6] != audiores)
+		return;
+	if(b[7] == 0){
+		int minfreq, maxfreq;
+
+		minfreq = b[8] | b[9]<<8 | b[10]<<16;
+		maxfreq = b[11] | b[12]<<8 | b[13]<<16;
+		if(minfreq > audiofreq || maxfreq < audiofreq)
+			return;
+	} else {
+		int freq;
+
+		for(i=0; i<b[7]; i++){
+			freq = b[8+3*i] | b[9+3*i]<<8 | b[10+3*i]<<16;
+			if(freq == audiofreq)
+				break;
+		}
+		if(i == b[7])
+			return;
+	}
+	dd->altc->aux = validaltc;
+}
+
+void
+usage(void)
+{
+	fprint(2, "%s devid\n", argv0);
+	exits("usage");
+}
+
+void
+main(int argc, char *argv[])
+{
+	Dev *d, *ed;
+	Usbdev *ud;
+	uchar b[4];
+	Altc *a;
+	Ep *e;
+	int i;
+
+	ARGBEGIN {
+	} ARGEND;
+
+	if(argc == 0)
+		usage();
+
+	if((d = getdev(atoi(*argv))) == nil)
+		sysfatal("getdev: %r");
+	if(configdev(d) < 0)
+		sysfatal("configdev: %r");
+
+	ud = d->usb;
+
+	/* parse descriptors, mark valid altc */
+	for(i = 0; i < nelem(ud->ddesc); i++)
+		parsedescr(ud->ddesc[i]);
+
+	for(i = 0; i < nelem(ud->ep); i++){
+		e = ud->ep[i];
+		if(e && e->iface && e->iface->csp == CSP(Claudio, 2, 0) && e->dir == Eout)
+			goto Foundendp;
+	}
+	sysfatal("no endpoints found");
+	return;
+
+Foundendp:
+	for(i = 0; i < nelem(e->iface->altc); i++){
+		a = e->iface->altc[i];
+		if(a && a->aux == validaltc)
+			goto Foundaltc;
+	}
+	sysfatal("no altc found");
+
+Foundaltc:
+	if(usbcmd(d, Rh2d|Rstd|Riface, Rsetiface, i, e->iface->id, nil, 0) < 0)
+		sysfatal("usbcmd: set altc: %r");
+
+	b[0] = audiofreq;
+	b[1] = audiofreq >> 8;
+	b[2] = audiofreq >> 16;
+	if(usbcmd(d, Rh2d|Rclass|Rep, Rsetcur, 0x100, e->addr, b, 3) < 0)
+		fprint(2, "warning: set freq: %r");
+
+	if((ed = openep(d, e->id)) == nil)
+		sysfatal("openep: %r");
+	devctl(ed, "pollival %d", 1);
+	devctl(ed, "samplesz %d", audiochan*audiores/8);
+	devctl(ed, "hz %d", audiofreq);
+
+	/* rename endpoint to #u/audio */
+	devctl(ed, "name audio");
+
+	exits(0);
+}

sys/src/cmd/nusb/audio/mkfile

@@ -0,0 +1,18 @@
+</$objtype/mkfile
+
+TARG=audio
+OFILES=audio.$O
+HFILES=../lib/usb.h
+
+LIB=../lib/usb.a$O
+
+BIN=/$objtype/bin/nusb
+
+UPDATE=\
+	mkfile\
+	$HFILES\
+	${OFILES:%.$O=%.c}\
+
+</sys/src/cmd/mkone
+CFLAGS=-I../lib $CFLAGS
+