beginnings of virtual playback channel support

instead of using two malloced arrays for storing channel lists, use an
slist.  convert the sndstat device to use sbufs and optionally provide more
detail about channel state.

vchans are software mixed playback channels.  they are not enabled by this
commit.  they use the feeder infrastructure to emulate normal playback
channels in a manner transparent to applications, whilst providing as many
channels are desired, especially suitable for devices with only one hardware
playback channel.  in the future they will provide additional features.

those wishing to test this functionality will need to add vchan.c to
sys/conf/files and use 'sysctl -w hw.snd.pcm0.vchans' to enable it.

blocksize and auto-rate selection are not yet supported.

1 files changed, 293 insertions, 145 deletions

diff --git a/sys/dev/sound/pcm/sound.c b/sys/dev/sound/pcm/sound.c
index a3039e3..7fb6951 100644
--- a/sys/dev/sound/pcm/sound.c
+++ b/sys/dev/sound/pcm/sound.c
@@ -28,12 +28,16 @@
  */
 
 #include <dev/sound/pcm/sound.h>
+#include <dev/sound/pcm/vchan.h>
 #include <sys/sysctl.h>
+#include <sys/sbuf.h>
 
-static dev_t 	status_dev = 0;
-static int 	status_isopen = 0;
-static int 	status_init(char *buf, int size);
-static int 	status_read(struct uio *buf);
+#include "feeder_if.h"
+
+#undef	SNDSTAT_VERBOSE
+
+static dev_t status_dev = 0;
+static int do_status(int action, struct uio *buf);
 
 static d_open_t sndopen;
 static d_close_t sndclose;
@@ -88,7 +92,7 @@ nomenclature:
 static devclass_t pcm_devclass;
 
 #ifdef USING_DEVFS
-int snd_unit;
+static int snd_unit;
 TUNABLE_INT_DECL("hw.snd.unit", 0, snd_unit);
 #endif
 
@@ -164,6 +168,36 @@ snd_setup_intr(device_t dev, struct resource *res, int flags, driver_intr_t hand
 	return bus_setup_intr(dev, res, flags, hand, param, cookiep);
 }
 
+struct pcm_channel *
+pcm_chnalloc(struct snddev_info *d, int direction)
+{
+	struct pcm_channel *c;
+    	struct snddev_channel *sce;
+
+	SLIST_FOREACH(sce, &d->channels, link) {
+		c = sce->channel;
+		if ((c->direction == direction) && !(c->flags & CHN_F_BUSY)) {
+			c->flags |= CHN_F_BUSY;
+			return c;
+		}
+	}
+	return NULL;
+}
+
+int
+pcm_chnfree(struct pcm_channel *c)
+{
+	c->flags &= ~CHN_F_BUSY;
+	return 0;
+}
+
+int
+pcm_chnref(struct pcm_channel *c, int ref)
+{
+	c->refcount += ref;
+	return c->refcount;
+}
+
 #ifdef USING_DEVFS
 static void
 pcm_makelinks(void *dummy)
@@ -171,6 +205,7 @@ pcm_makelinks(void *dummy)
 	int unit;
 	dev_t pdev;
 	static dev_t dsp = 0, dspW = 0, audio = 0, mixer = 0;
+    	struct snddev_info *d;
 
 	if (pcm_devclass == NULL || devfs_present == 0)
 		return;
@@ -194,7 +229,8 @@ pcm_makelinks(void *dummy)
 	unit = snd_unit;
 	if (unit < 0 || unit > devclass_get_maxunit(pcm_devclass))
 		return;
-	if (devclass_get_softc(pcm_devclass, unit) == NULL)
+	d = devclass_get_softc(pcm_devclass, unit);
+	if (d == NULL || d->chancount == 0)
 		return;
 
 	pdev = makedev(CDEV_MAJOR, PCMMKMINOR(unit, SND_DEV_DSP, 0));
@@ -224,32 +260,86 @@ SYSCTL_PROC(_hw_snd, OID_AUTO, unit, CTLTYPE_INT | CTLFLAG_RW,
             0, sizeof(int), sysctl_hw_sndunit, "I", "");
 #endif
 
-int
-pcm_addchan(device_t dev, int dir, kobj_class_t cls, void *devinfo)
+struct pcm_channel *
+pcm_chn_create(struct snddev_info *d, struct pcm_channel *parent, kobj_class_t cls, int dir, void *devinfo)
 {
-    	int unit = device_get_unit(dev), idx;
-    	struct snddev_info *d = device_get_softc(dev);
-	struct pcm_channel *chns, *ch;
+	struct pcm_channel *ch;
 	char *dirs;
-	int err;
-
-	dirs = ((dir == PCMDIR_PLAY)? "play" : "record");
-	chns = ((dir == PCMDIR_PLAY)? d->play : d->rec);
-	idx = ((dir == PCMDIR_PLAY)? d->playcount++ : d->reccount++);
+    	int err;
 
-	if (chns == NULL) {
-		device_printf(dev, "bad channel add (%s:%d)\n", dirs, idx);
-		return 1;
+	switch(dir) {
+	case PCMDIR_PLAY:
+		dirs = "play";
+		break;
+	case PCMDIR_REC:
+		dirs = "record";
+		break;
+	case PCMDIR_VIRTUAL:
+		dirs = "virtual";
+		dir = PCMDIR_PLAY;
+		break;
+	default:
+		return NULL;
 	}
-	ch = &chns[idx];
+
+	ch = malloc(sizeof(*ch), M_DEVBUF, M_WAITOK | M_ZERO);
+	if (!ch)
+		return NULL;
+
 	ch->methods = kobj_create(cls, M_DEVBUF, M_WAITOK);
-	ch->parent = d;
-	snprintf(ch->name, 32, "%s:%s:%d", device_get_nameunit(dev), dirs, idx);
+	if (!ch->methods) {
+		free(ch, M_DEVBUF);
+		return NULL;
+	}
+
+	ch->pid = -1;
+	ch->parentsnddev = d;
+	ch->parentchannel = parent;
+	snprintf(ch->name, 32, "%s:%d:%s", device_get_nameunit(d->dev), d->chancount, dirs);
+
 	err = chn_init(ch, devinfo, dir);
 	if (err) {
-		device_printf(dev, "chn_init() for (%s:%d) failed: err = %d\n", dirs, idx, err);
-		return 1;
+		device_printf(d->dev, "chn_init() for channel %d (%s) failed: err = %d\n", d->chancount, dirs, err);
+		kobj_delete(ch->methods, M_DEVBUF);
+		free(ch, M_DEVBUF);
+		return NULL;
+	}
+
+	return ch;
+}
+
+int
+pcm_chn_destroy(struct pcm_channel *ch)
+{
+	int err;
+
+	err = chn_kill(ch);
+	if (err) {
+		device_printf(ch->parentsnddev->dev, "chn_kill() for %s failed, err = %d\n", ch->name, err);
+		return err;
 	}
+
+	kobj_delete(ch->methods, M_DEVBUF);
+	free(ch, M_DEVBUF);
+
+	return 0;
+}
+
+int
+pcm_chn_add(struct snddev_info *d, struct pcm_channel *ch)
+{
+    	struct snddev_channel *sce;
+    	int unit = device_get_unit(d->dev);
+
+	sce = malloc(sizeof(*sce), M_DEVBUF, M_WAITOK | M_ZERO);
+	if (!sce) {
+		free(ch, M_DEVBUF);
+		return ENOMEM;
+	}
+
+	sce->channel = ch;
+	SLIST_INSERT_HEAD(&d->channels, sce, link);
+
 	make_dev(&snd_cdevsw, PCMMKMINOR(unit, SND_DEV_DSP, d->chancount),
 		 UID_ROOT, GID_WHEEL, 0666, "dsp%d.%d", unit, d->chancount);
 	make_dev(&snd_cdevsw, PCMMKMINOR(unit, SND_DEV_DSP16, d->chancount),
@@ -257,49 +347,79 @@ pcm_addchan(device_t dev, int dir, kobj_class_t cls, void *devinfo)
 	make_dev(&snd_cdevsw, PCMMKMINOR(unit, SND_DEV_AUDIO, d->chancount),
 		 UID_ROOT, GID_WHEEL, 0666, "audio%d.%d", unit, d->chancount);
 	/* XXX SND_DEV_NORESET? */
-	d->chancount++;
+
 #ifdef USING_DEVFS
-    	if (d->chancount == 1)
+    	if (d->chancount++ == 0)
 		pcm_makelinks(NULL);
 #endif
+
 	return 0;
 }
 
-static int
-pcm_killchan(device_t dev, int dir)
+int
+pcm_chn_remove(struct snddev_info *d, struct pcm_channel *ch)
 {
-    	int unit = device_get_unit(dev), idx;
-    	struct snddev_info *d = device_get_softc(dev);
-	struct pcm_channel *chns, *ch;
-	char *dirs;
+    	struct snddev_channel *sce;
+    	int unit = device_get_unit(d->dev);
 	dev_t pdev;
 
-	dirs = ((dir == PCMDIR_PLAY)? "play" : "record");
-	chns = ((dir == PCMDIR_PLAY)? d->play : d->rec);
-	idx = ((dir == PCMDIR_PLAY)? --d->playcount : --d->reccount);
-
-	if (chns == NULL || idx < 0) {
-		device_printf(dev, "bad channel kill (%s:%d)\n", dirs, idx);
-		return 1;
-	}
-	ch = &chns[idx];
-	if (chn_kill(ch)) {
-		device_printf(dev, "chn_kill() for (%s:%d) failed\n", dirs, idx);
-		return 1;
+	SLIST_FOREACH(sce, &d->channels, link) {
+		if (sce->channel == ch)
+			goto gotit;
 	}
-	kobj_delete(ch->methods, M_DEVBUF);
-	ch->methods = NULL;
+	return EINVAL;
+gotit:
 	d->chancount--;
+	SLIST_REMOVE(&d->channels, sce, snddev_channel, link);
+	free(sce, M_DEVBUF);
+
+#ifdef USING_DEVFS
+    	if (d->chancount == 0)
+		pcm_makelinks(NULL);
+#endif
 	pdev = makedev(CDEV_MAJOR, PCMMKMINOR(unit, SND_DEV_DSP, d->chancount));
 	destroy_dev(pdev);
 	pdev = makedev(CDEV_MAJOR, PCMMKMINOR(unit, SND_DEV_DSP16, d->chancount));
 	destroy_dev(pdev);
 	pdev = makedev(CDEV_MAJOR, PCMMKMINOR(unit, SND_DEV_AUDIO, d->chancount));
 	destroy_dev(pdev);
+
 	return 0;
 }
 
 int
+pcm_addchan(device_t dev, int dir, kobj_class_t cls, void *devinfo)
+{
+    	struct snddev_info *d = device_get_softc(dev);
+	struct pcm_channel *ch;
+    	int err;
+
+	ch = pcm_chn_create(d, NULL, cls, dir, devinfo);
+	if (!ch) {
+		device_printf(d->dev, "pcm_chn_create(%s, %d, %p) failed\n", cls->name, dir, devinfo);
+		return ENODEV;
+	}
+	err = pcm_chn_add(d, ch);
+	if (err) {
+		device_printf(d->dev, "pcm_chn_add(%s) failed, err=%d\n", ch->name, err);
+		pcm_chn_destroy(ch);
+	}
+
+	return err;
+}
+
+static int
+pcm_killchan(device_t dev)
+{
+    	struct snddev_info *d = device_get_softc(dev);
+    	struct snddev_channel *sce;
+
+	sce = SLIST_FIRST(&d->channels);
+
+	return pcm_chn_remove(d, sce->channel);
+}
+
+int
 pcm_setstatus(device_t dev, char *str)
 {
     	struct snddev_info *d = device_get_softc(dev);
@@ -340,44 +460,27 @@ pcm_register(device_t dev, void *devinfo, int numplay, int numrec)
 		status_dev = make_dev(&snd_cdevsw, PCMMKMINOR(0, SND_DEV_STATUS, 0),
 			 UID_ROOT, GID_WHEEL, 0444, "sndstat");
 	}
+
 	make_dev(&snd_cdevsw, PCMMKMINOR(unit, SND_DEV_CTL, 0),
 		 UID_ROOT, GID_WHEEL, 0666, "mixer%d", unit);
+
 	d->dev = dev;
 	d->devinfo = devinfo;
-	d->chancount = d->playcount = d->reccount = 0;
+	d->chancount = 0;
 	d->maxchans = numplay + numrec;
-    	sz = (numplay + numrec) * sizeof(struct pcm_channel *);
+    	sz = d->maxchans * sizeof(struct pcm_channel *);
 
 	if (sz > 0) {
-		d->aplay = (struct pcm_channel **)malloc(sz, M_DEVBUF, M_NOWAIT);
-    		if (!d->aplay) goto no;
-    		bzero(d->aplay, sz);
-
-    		d->arec = (struct pcm_channel **)malloc(sz, M_DEVBUF, M_NOWAIT);
-    		if (!d->arec) goto no;
-    		bzero(d->arec, sz);
-
-    		sz = (numplay + numrec) * sizeof(int);
-		d->ref = (int *)malloc(sz, M_DEVBUF, M_NOWAIT);
-    		if (!d->ref) goto no;
-    		bzero(d->ref, sz);
-	}
+		d->aplay = (struct pcm_channel **)malloc(sz, M_DEVBUF, M_WAITOK | M_ZERO);
+    		d->arec = (struct pcm_channel **)malloc(sz, M_DEVBUF, M_WAITOK | M_ZERO);
+    		if (!d->arec || !d->aplay) goto no;
 
-	if (numplay > 0) {
-    		d->play = (struct pcm_channel *)malloc(numplay * sizeof(struct pcm_channel),
-						M_DEVBUF, M_NOWAIT);
-    		if (!d->play) goto no;
-    		bzero(d->play, numplay * sizeof(struct pcm_channel));
-	} else
-		d->play = NULL;
-
-	if (numrec > 0) {
-	  	d->rec = (struct pcm_channel *)malloc(numrec * sizeof(struct pcm_channel),
-				       	M_DEVBUF, M_NOWAIT);
-    		if (!d->rec) goto no;
-    		bzero(d->rec, numrec * sizeof(struct pcm_channel));
-	} else
-		d->rec = NULL;
+		if (numplay == 0 || numrec == 0)
+			d->flags |= SD_F_SIMPLEX;
+
+		d->fakechan = fkchan_setup(dev);
+		chn_init(d->fakechan, NULL, 0);
+	}
 
 #ifdef SND_DYNSYSCTL
 	sysctl_ctx_init(&d->sysctl_tree);
@@ -389,36 +492,29 @@ pcm_register(device_t dev, void *devinfo, int numplay, int numrec)
 		goto no;
 	}
 #endif
-
-	if (numplay == 0 || numrec == 0)
-		d->flags |= SD_F_SIMPLEX;
-
-	d->fakechan = fkchan_setup(dev);
-	chn_init(d->fakechan, NULL, 0);
-
+#if 0
+	vchan_initsys(d);
+#endif
     	return 0;
 no:
 	if (d->aplay) free(d->aplay, M_DEVBUF);
-	if (d->play) free(d->play, M_DEVBUF);
 	if (d->arec) free(d->arec, M_DEVBUF);
-	if (d->rec) free(d->rec, M_DEVBUF);
-	if (d->ref) free(d->ref, M_DEVBUF);
 	return ENXIO;
 }
 
 int
 pcm_unregister(device_t dev)
 {
-    	int r, i, unit = device_get_unit(dev);
+    	int unit = device_get_unit(dev);
     	struct snddev_info *d = device_get_softc(dev);
+    	struct snddev_channel *sce;
 	dev_t pdev;
 
-	r = 0;
-	for (i = 0; i < d->chancount; i++)
-		if (d->ref[i]) r = EBUSY;
-	if (r) {
-		device_printf(dev, "unregister: channel busy");
-		return r;
+	SLIST_FOREACH(sce, &d->channels, link) {
+		if (sce->channel->refcount > 0) {
+			device_printf(dev, "unregister: channel busy");
+			return EBUSY;
+		}
 	}
 	if (mixer_isbusy(d->mixer)) {
 		device_printf(dev, "unregister: mixer busy");
@@ -434,23 +530,15 @@ pcm_unregister(device_t dev)
 	destroy_dev(pdev);
 	mixer_uninit(dev);
 
-	while (d->playcount > 0)
-		pcm_killchan(dev, PCMDIR_PLAY);
-	while (d->reccount > 0)
-		pcm_killchan(dev, PCMDIR_REC);
+	while (d->chancount > 0)
+		pcm_killchan(dev);
 
 	if (d->aplay) free(d->aplay, M_DEVBUF);
-	if (d->play) free(d->play, M_DEVBUF);
 	if (d->arec) free(d->arec, M_DEVBUF);
-	if (d->rec) free(d->rec, M_DEVBUF);
-	if (d->ref) free(d->ref, M_DEVBUF);
 
 	chn_kill(d->fakechan);
 	fkchan_kill(d->fakechan);
 
-#ifdef USING_DEVFS
-	pcm_makelinks(NULL);
-#endif
 	return 0;
 }
 
@@ -506,9 +594,7 @@ sndopen(dev_t i_dev, int flags, int mode, struct proc *p)
 
     	switch(dev) {
     	case SND_DEV_STATUS:
-		if (status_isopen) return EBUSY;
-		status_isopen = 1;
-		return 0;
+		return do_status(0, NULL);
 
     	case SND_DEV_CTL:
 		return d? mixer_busy(d->mixer, 1) : ENXIO;
@@ -517,7 +603,7 @@ sndopen(dev_t i_dev, int flags, int mode, struct proc *p)
     	case SND_DEV_DSP:
     	case SND_DEV_DSP16:
 	case SND_DEV_NORESET:
-		return d? dsp_open(d, chan, flags, dev) : ENXIO;
+		return d? dsp_open(d, chan, flags, dev, p->p_pid) : ENXIO;
 
     	default:
     		return ENXIO;
@@ -534,9 +620,7 @@ sndclose(dev_t i_dev, int flags, int mode, struct proc *p)
 
     	switch(dev) { /* only those for which close makes sense */
     	case SND_DEV_STATUS:
-		if (!status_isopen) return EBADF;
-		status_isopen = 0;
-		return 0;
+		return do_status(1, NULL);
 
     	case SND_DEV_CTL:
 		return d? mixer_busy(d->mixer, 0) : ENXIO;
@@ -560,7 +644,7 @@ sndread(dev_t i_dev, struct uio *buf, int flag)
 
     	switch(dev) {
     	case SND_DEV_STATUS:
-		return status_isopen? status_read(buf) : EBADF;
+		return do_status(2, buf);
 
     	case SND_DEV_AUDIO:
     	case SND_DEV_DSP:
@@ -675,52 +759,116 @@ sndmmap(dev_t i_dev, vm_offset_t offset, int nprot)
 }
 
 static int
-status_init(char *buf, int size)
+status_init(struct sbuf *s)
 {
-    	int             i;
-    	device_t	    dev;
-    	struct snddev_info     *d;
+    	int i, pc, rc, vc;
+    	device_t dev;
+    	struct snddev_info *d;
+    	struct snddev_channel *sce;
+	struct pcm_channel *c;
+	struct pcm_feeder *f;
 
-    	snprintf(buf, size, "FreeBSD Audio Driver (newpcm) %s %s\n"
-		 "Installed devices:\n", __DATE__, __TIME__);
+	sbuf_printf(s, "FreeBSD Audio Driver (newpcm) %s %s\nInstalled devices:\n",
+		 	__DATE__, __TIME__);
 
     	for (i = 0; i <= devclass_get_maxunit(pcm_devclass); i++) {
 		d = devclass_get_softc(pcm_devclass, i);
-		if (!d) continue;
+		if (!d)
+			continue;
 		dev = devclass_get_device(pcm_devclass, i);
-        	if (1) {
-			snprintf(buf + strlen(buf), size - strlen(buf),
-		            	"pcm%d: <%s> %s",
-		            	i, device_get_desc(dev), d->status);
-			if (d->chancount > 0)
-				snprintf(buf + strlen(buf), size - strlen(buf),
-				" (%dp/%dr channels%s)\n",
-			    	d->playcount, d->reccount,
-			    	(!(d->flags & SD_F_SIMPLEX))? " duplex" : "");
-			else
-				snprintf(buf + strlen(buf), size - strlen(buf),
-				" (mixer only)\n");
-		}
+		sbuf_printf(s, "pcm%d: <%s> %s", i, device_get_desc(dev), d->status);
+		if (d->chancount > 0) {
+			pc = rc = vc = 0;
+			SLIST_FOREACH(sce, &d->channels, link) {
+				c = sce->channel;
+				if (c->direction == PCMDIR_PLAY) {
+					if (c->flags & CHN_F_VIRTUAL)
+						vc++;
+					else
+						pc++;
+				} else
+					rc++;
+			}
+			sbuf_printf(s, " (%dp/%dr/%dv channels%s%s)\n", pc, rc, vc,
+					(d->flags & SD_F_SIMPLEX)? "" : " duplex",
+#ifdef USING_DEVFS
+					(i == snd_unit)? " default" : ""
+#else
+					""
+#endif
+					);
+#ifdef SNDSTAT_VERBOSE
+			SLIST_FOREACH(sce, &d->channels, link) {
+				c = sce->channel;
+				sbuf_printf(s, "\t%s[%s]: speed %d, format %08x, flags %08x",
+					c->parentchannel? c->parentchannel->name : "",
+					c->name, c->speed, c->format, c->flags);
+				if (c->pid != -1)
+					sbuf_printf(s, ", pid %d", c->pid);
+				sbuf_printf(s, "\n\t");
+				f = c->feeder;
+				while (f) {
+					sbuf_printf(s, "%s", f->class->name);
+					if (f->desc->type == FEEDER_FMT)
+						sbuf_printf(s, "(%08x <- %08x)", f->desc->out, f->desc->in);
+					if (f->desc->type == FEEDER_RATE)
+						sbuf_printf(s, "(%d <- %d)", FEEDER_GET(f, FEEDRATE_DST), FEEDER_GET(f, FEEDRATE_SRC));
+					if (f->desc->type == FEEDER_ROOT || f->desc->type == FEEDER_MIXER)
+						sbuf_printf(s, "(%08x)", f->desc->out);
+					if (f->source)
+						sbuf_printf(s, " <- ");
+					f = f->source;
+				}
+				sbuf_printf(s, "\n");
+			}
+#endif
+		} else
+			sbuf_printf(s, " (mixer only)\n");
     	}
-    	return strlen(buf);
+	sbuf_finish(s);
+    	return sbuf_len(s);
 }
 
 static int
-status_read(struct uio *buf)
+do_status(int action, struct uio *buf)
 {
-    	static char	status_buf[4096];
-    	static int 	bufptr = 0, buflen = 0;
-    	int l;
-
-    	if (status_isopen == 1) {
-		status_isopen++;
+	static struct sbuf s;
+    	static int bufptr = 0;
+	static int status_open = 0;
+    	int l, err;
+
+	switch(action) {
+	case 0: /* open */
+		if (status_open)
+			return EBUSY;
+		if (sbuf_new(&s, NULL, 4096, 0))
+			return ENXIO;
 		bufptr = 0;
-		buflen = status_init(status_buf, sizeof status_buf);
-    	}
+		err = (status_init(&s) > 0)? 0 : ENOMEM;
+		if (!err)
+			status_open = 1;
+		return err;
+
+	case 1: /* close */
+		if (!status_open)
+			return EBADF;
+		sbuf_delete(&s);
+		status_open = 0;
+		return 0;
+
+	case 2:
+		if (!status_open)
+			return EBADF;
+	    	l = min(buf->uio_resid, sbuf_len(&s) - bufptr);
+		err = (l > 0)? uiomove(sbuf_data(&s) + bufptr, l, buf) : 0;
+    		bufptr += l;
+    		return err;
+
+	case 3:
+		return status_open;
+	}
 
-    	l = min(buf->uio_resid, buflen - bufptr);
-    	bufptr += l;
-    	return (l > 0)? uiomove(status_buf + bufptr - l, l, buf) : 0;
+	return EBADF;
 }
 
 static int
@@ -731,7 +879,7 @@ sndpcm_modevent(module_t mod, int type, void *data)
 	case MOD_LOAD:
 		break;
 	case MOD_UNLOAD:
-		if (status_isopen)
+		if (do_status(3, NULL))
 			return EBUSY;
 		if (status_dev)
 			destroy_dev(status_dev);