usbaudioctl.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 <libc.h>
#include <thread.h>
#include "usb.h"
#include "usbaudio.h"
#include "usbaudioctl.h"

int endpt[2] =		{-1, -1};
int interface[2] =	{-1, -1};
int featureid[2] =	{-1, -1};
int selectorid[2] =	{-1, -1};
int mixerid[2] =	{-1, -1};
int curalt[2] =		{-1, -1};
int buttonendpt =	-1;

int id;
Device *ad;

Audiocontrol controls[2][Ncontrol] = {
	{
	[Speed_control] = {		"speed",	0, {0}, 0,	44100,	Undef},
	[Mute_control] = {		"mute",		0, {0}, 0,	0,	Undef},
	[Volume_control] = {		"volume",	0, {0}, 0,	0,	Undef},
	[Bass_control] = {		"bass",		0, {0}, 0,	0,	Undef},
	[Mid_control] = {		"mid",		0, {0}, 0,	0,	Undef},
	[Treble_control] = {		"treble",	0, {0}, 0,	0,	Undef},
	[Equalizer_control] = {		"equalizer",	0, {0}, 0,	0,	Undef},
	[Agc_control] = {		"agc",		0, {0}, 0,	0,	Undef},
	[Delay_control] = {		"delay",	0, {0}, 0,	0,	Undef},
	[Bassboost_control] = {		"bassboost",	0, {0}, 0,	0,	Undef},
	[Loudness_control] = {		"loudness",	0, {0}, 0,	0,	Undef},
	[Channel_control] = {		"channels",	0, {0}, 0,	2,	Undef},
	[Resolution_control] = {	"resolution",	0, {0}, 0,	16,	Undef},
//	[Selector_control] = {		"selector",	0, {0}, 0,	0,	Undef},
	}, {
	[Speed_control] = {		"speed",	0, {0}, 0,	44100,	Undef},
	[Mute_control] = {		"mute",		0, {0}, 0,	0,	Undef},
	[Volume_control] = {		"volume",	0, {0}, 0,	0,	Undef},
	[Bass_control] = {		"bass",		0, {0}, 0,	0,	Undef},
	[Mid_control] = {		"mid",		0, {0}, 0,	0,	Undef},
	[Treble_control] = {		"treble",	0, {0}, 0,	0,	Undef},
	[Equalizer_control] = {		"equalizer",	0, {0}, 0,	0,	Undef},
	[Agc_control] = {		"agc",		0, {0}, 0,	0,	Undef},
	[Delay_control] = {		"delay",	0, {0}, 0,	0,	Undef},
	[Bassboost_control] = {		"bassboost",	0, {0}, 0,	0,	Undef},
	[Loudness_control] = {		"loudness",	0, {0}, 0,	0,	Undef},
	[Channel_control] = {		"channels",	0, {0}, 0,	2,	Undef},
	[Resolution_control] = {	"resolution",	0, {0}, 0,	16,	Undef},
//	[Selector_control] = {		"selector",	0, {0}, 0,	0,	Undef},
	}
};

int
setaudioalt(int rec, Audiocontrol *c, int control)
{
	if (debug & Dbgcontrol)
		fprint(2, "setcontrol %s: Set alt %d\n", c->name, control);
	curalt[rec] = control;
	if (setupcmd(ad->ep[0], RH2D|Rstandard|Rinterface, SET_INTERFACE, control, interface[rec], nil, 0) < 0){
		if (debug & Dbgcontrol) fprint(2, "setcontrol: setupcmd %s failed\n", c->name);
			return -1;
	}
	return control;
}

int
findalt(int rec, int nchan, int res, int speed)
{
	Endpt *ep;
	Audioalt *a;
	Dalt *da;
	int i, j, k, retval;

	retval = -1;
	controls[rec][Channel_control].min = 1000000;
	controls[rec][Channel_control].max = 0;
	controls[rec][Channel_control].step = Undef;
	controls[rec][Resolution_control].min = 1000000;
	controls[rec][Resolution_control].max = 0;
	controls[rec][Resolution_control].step = Undef;
	for (i = 0; i < Nendpt; i++) {
		if ((ep = ad->ep[i]) == nil)
			continue;
		if(ep->csp != CSP(CL_AUDIO, 2, 0))
			continue;
		if (ep->iface == nil) {
			fprint(2, "\tno interface\n");
			return 0;
		}
		if ((rec == Play && (ep->addr &  0x80))
		|| (rec == Record && (ep->addr &  0x80) == 0))
			continue;
		for (j = 0; j < 16; j++) {
			if ((da = ep->iface->dalt[j]) == nil || (a = da->devspec) == nil)
				continue;
			if (a->nchan < controls[rec][Channel_control].min)
				controls[rec][Channel_control].min = a->nchan;
			if (a->nchan > controls[rec][Channel_control].max)
				controls[rec][Channel_control].max = a->nchan;
			if (a->res < controls[rec][Resolution_control].min)
				controls[rec][Resolution_control].min = a->res;
			if (a->res > controls[rec][Resolution_control].max)
				controls[rec][Resolution_control].max = a->res;
			controls[rec][Channel_control].settable = 1;
			controls[rec][Channel_control].readable = 1;
			controls[rec][Resolution_control].settable = 1;
			controls[rec][Resolution_control].readable = 1;
			controls[rec][Speed_control].settable = 1;
			controls[rec][Speed_control].readable = 1;
			if (a->nchan == nchan && a->res == res){
				if(speed == Undef)
					retval = j;
				else if(a->caps & (has_discfreq|onefreq)){
					for(k = 0; k < nelem(a->freqs); k++){
						if(a->freqs[k] == speed){
							retval = j;
							break;
						}
					}
				} else {
					if(speed >= a->minfreq && speed <= a->maxfreq)
						retval = j;
				}
			}
		}
	}
	if ((debug & Dbgcontrol) && retval < 0){
		fprint(2, "findalt(%d, %d, %d, %d) failed\n", rec, nchan, res, speed);
	}
	return retval;
}

int
setspeed(int rec, int speed)
{
	int ps, n, no, dist, i;
	Audioalt *a;
	Dalt *da;
	Endpt *ep;
	char cmdbuf[32];
	uchar buf[3];

	if (curalt[rec] < 0){
		fprint(2, "Must set channels and resolution before speed\n");
		return Undef;
	}
	if (endpt[rec] < 0)
		sysfatal("endpt[%s] not set\n", rec?"Record":"Playback");
	ep = ad->ep[endpt[rec]];
	if (ep->iface == nil)
		sysfatal("no interface");
	if (curalt[rec] < 0)
		sysfatal("curalt[%s] not set\n", rec?"Record":"Playback");
	da = ep->iface->dalt[curalt[rec]];
	a = da->devspec;
	if (a->caps & onefreq){
		if (debug & Dbgcontrol)
			fprint(2, "setspeed %d: onefreq\n", speed);
		speed = a->freqs[0];		/* speed not settable, but packet size must still be set */
	}else if (a->caps & has_contfreq){
		if (debug & Dbgcontrol)
			fprint(2, "setspeed %d: contfreq\n", speed);
		if (speed < a->minfreq)
			speed = a->minfreq;
		else if (speed > a->maxfreq)
			speed = a->maxfreq;
		if (debug & Dbgcontrol)
			fprint(2, "Setting continuously variable %s speed to %d\n",
				rec?"record":"playback", speed);
	}else if (a->caps & has_discfreq){
		if (debug & Dbgcontrol)
			fprint(2, "setspeed %d: discfreq\n", speed);
		dist = 1000000;
		no = -1;
		for (i = 0; a->freqs[i] > 0; i++)
			if (abs(a->freqs[i] - speed) < dist){
				dist = abs(a->freqs[i] - speed);
				no = i;
			}
		if (no == -1){
			if (debug & Dbgcontrol)
				fprint(2, "no = -1\n");
			return Undef;
		}
		speed = a->freqs[no];
		if (debug & Dbgcontrol)
			fprint(2, "Setting discreetly variable %s speed to %d\n",
				rec?"record":"playback", speed);
	}else{
		if (debug & Dbgcontrol)
			fprint(2, "can't happen\n?");
		return Undef;
	}
	if (a->caps & has_setspeed){
		if (debug & Dbgcontrol)
			fprint(2, "Setting %s speed to %d Hz;", rec?"record":"playback", speed);
		buf[0] = speed;
		buf[1] = speed >> 8;
		buf[2] = speed >> 16;
		if(setupcmd(ad->ep[0], RH2D|Rclass|Rendpt, SET_CUR, sampling_freq_control<<8, endpt[rec], buf, 3) < 0){
			fprint(2, "Error in setupcmd\n");
			return Undef;
		}
		if (setupreq(ad->ep[0], RD2H|Rclass|Rendpt, GET_CUR, sampling_freq_control<<8, endpt[rec], 3) < 0){
			fprint(2, "Error in setupreq\n");
			return Undef;
		}
		n = setupreply(ad->ep[0], buf, 3);
		if (n != 3)
			fprint(2, "Error in setupreply: %d\n", n);
		else if (buf[2]){
			if (debug & Dbgcontrol)
				fprint(2, "Speed out of bounds %d (0x%x)\n",
					buf[0] | buf[1] << 8 | buf[2] << 16,
					buf[0] | buf[1] << 8 | buf[2] << 16);
		}else
			speed = buf[0] | buf[1] << 8 | buf[2] << 16;
		if (debug & Dbgcontrol)
			fprint(2, " speed now %d Hz;", speed);
	}
	ps = ((speed * da->interval + 999) / 1000)
		* controls[rec][Channel_control].value[0]
		* controls[rec][Resolution_control].value[0]/8;
	if(ps > ep->maxpkt){
		fprint(2, "packet size %d > maximum packet size %d\n",
			ps, ep->maxpkt);
		return Undef;
	}
	if (debug & Dbgcontrol)
		fprint(2, "Configuring %s endpoint for %d Hz\n",
				rec?"record":"playback", speed);
	sprint(cmdbuf, "ep %d %d %c %ld %d", endpt[rec], da->interval, rec?'r':'w', 
		controls[rec][Channel_control].value[0]*controls[rec][Resolution_control].value[0]/8,
		speed);
	if (write(ad->ctl, cmdbuf, strlen(cmdbuf)) != strlen(cmdbuf)){
		fprint(2, "writing %s to #U/usb/%d/ctl: %r\n", cmdbuf, id);
		return Undef;
	}
	if (debug & Dbgcontrol) fprint(2, "sent `%s' to /dev/usb/%d/ctl\n", cmdbuf, id);
	return speed;
}

long
getspeed(int rec, int which)
{
	int i, n;
	Audioalt *a;
	Dalt *da;
	Endpt *ep;
	uchar buf[3];

	if (curalt[rec] < 0){
		fprint(2, "Must set channels and resolution before getspeed\n");
		return Undef;
	}
	if (endpt[rec] < 0)
		sysfatal("endpt[%s] not set\n", rec?"Record":"Playback");
	if(debug & Dbgcontrol)
		fprint(2, "getspeed: curalt[%d] == %d\n", rec, endpt[rec]);
	ep = ad->ep[endpt[rec]];
	if (ep->iface == nil)
		sysfatal("no interface");
	if (curalt[rec] < 0)
		sysfatal("curalt[%s] not set\n", rec?"Record":"Playback");
	da = ep->iface->dalt[curalt[rec]];
	a = da->devspec;
	if (a->caps & onefreq){
		if(debug & Dbgcontrol)
			fprint(2, "getspeed: onefreq\n");
		if (which == GET_RES)
			return Undef;
		return a->freqs[0];		/* speed not settable */
	}
	if (a->caps & has_setspeed){
		if(debug & Dbgcontrol)
			fprint(2, "getspeed: has_setspeed, ask\n");
		if (setupreq(ad->ep[0], RD2H|Rclass|Rendpt, which, sampling_freq_control<<8, endpt[rec], 3) < 0)
			return Undef;
		n = setupreply(ad->ep[0], buf, 3);
		if(n == 3){
			if(buf[2]){
				if (debug & Dbgcontrol)
					fprint(2, "Speed out of bounds\n");
				if ((a->caps & has_discfreq) && (buf[0] | buf[1] << 8) < 8)
					return a->freqs[buf[0] | buf[1] << 8];
			}
			return buf[0] | buf[1] << 8 | buf[2] << 16;
		}
		if(debug & Dbgcontrol)
			fprint(2, "getspeed: n = %d\n", n);
	}
	if (a->caps & has_contfreq){
		if(debug & Dbgcontrol)
			fprint(2, "getspeed: has_contfreq\n");
		if (which == GET_CUR)
			return controls[rec][Speed_control].value[0];
		if (which == GET_MIN)
			return a->minfreq;
		if (which == GET_MAX)
			return a->maxfreq;
		if (which == GET_RES)
			return 1;
	}
	if (a->caps & has_discfreq){
		if(debug & Dbgcontrol)
			fprint(2, "getspeed: has_discfreq\n");
		if (which == GET_CUR)
			return controls[rec][Speed_control].value[0];
		if (which == GET_MIN)
			return a->freqs[0];
		for (i = 0; i < 8 && a->freqs[i] > 0; i++)
			;
		if (which == GET_MAX)
			return a->freqs[i-1];
		if (which == GET_RES)
			return Undef;
	}
	if (debug & Dbgcontrol)
		fprint(2, "can't happen\n?");
	return Undef;
}

int
setcontrol(int rec, char *name, long *value)
{
	int i, ctl, m;
	byte buf[3];
	int type, req, control, index, count;
	Audiocontrol *c;

	c = nil;
	for (ctl = 0; ctl < Ncontrol; ctl++){
		c = &controls[rec][ctl];
		if (strcmp(name, c->name) == 0)
			break;
	}
	if (ctl == Ncontrol){
		if (debug & Dbgcontrol) fprint(2, "setcontrol: control not found\n");
		return -1;
	}
	if (c->settable == 0) {
		if (debug & Dbgcontrol) fprint(2, "setcontrol: control %d.%d not settable\n", rec, ctl);
		if (c->chans){
			for (i = 0; i < 8; i++)
				if ((c->chans & 1 << i) && c->value[i] != value[i])