audio: basic support for multi backend audio

Audio functions no longer access glob_audio_state, instead they get an
AudioState as a parameter.  This is required in order to support
multiple backends.

glob_audio_state is also gone, and replaced with a tailq so we can store
more than one states.

Signed-off-by: Kővágó, Zoltán <DirtY.iCE.hu@gmail.com>
Message-id: 67aef54f9e729a7160fe95c465351115e392164b.1566168923.git.DirtY.iCE.hu@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

audio/audio.c

@@ -87,7 +87,8 @@ audio_driver *audio_driver_lookup(const char *name)
     return NULL;
 }
 
-static AudioState glob_audio_state;
+static QTAILQ_HEAD(AudioStateHead, AudioState) audio_states =
+    QTAILQ_HEAD_INITIALIZER(audio_states);
 
 const struct mixeng_volume nominal_volume = {
     .mute = 0,
@@ -1238,11 +1239,14 @@ static void audio_run_capture (AudioState *s)
 
 void audio_run (const char *msg)
 {
-    AudioState *s = &glob_audio_state;
+    AudioState *s;
+
+    QTAILQ_FOREACH(s, &audio_states, list) {
+        audio_run_out(s);
+        audio_run_in(s);
+        audio_run_capture(s);
+    }
 
-    audio_run_out (s);
-    audio_run_in (s);
-    audio_run_capture (s);
 #ifdef DEBUG_POLL
     {
         static double prevtime;
@@ -1306,13 +1310,11 @@ bool audio_is_cleaning_up(void)
     return is_cleaning_up;
 }
 
-void audio_cleanup(void)
+static void free_audio_state(AudioState *s)
 {
-    AudioState *s = &glob_audio_state;
     HWVoiceOut *hwo, *hwon;
     HWVoiceIn *hwi, *hwin;
 
-    is_cleaning_up = true;
     QLIST_FOREACH_SAFE(hwo, &s->hw_head_out, entries, hwon) {
         SWVoiceCap *sc;
 
@@ -1349,6 +1351,17 @@ void audio_cleanup(void)
         qapi_free_Audiodev(s->dev);
         s->dev = NULL;
     }
+    g_free(s);
+}
+
+void audio_cleanup(void)
+{
+    is_cleaning_up = true;
+    while (!QTAILQ_EMPTY(&audio_states)) {
+        AudioState *s = QTAILQ_FIRST(&audio_states);
+        QTAILQ_REMOVE(&audio_states, s, list);
+        free_audio_state(s);
+    }
 }
 
 static const VMStateDescription vmstate_audio = {
@@ -1375,28 +1388,33 @@ static AudiodevListEntry *audiodev_find(
     return NULL;
 }
 
-static int audio_init(Audiodev *dev)
+/*
+ * if we have dev, this function was called because of an -audiodev argument =>
+ *   initialize a new state with it
+ * if dev == NULL => legacy implicit initialization, return the already created
+ *   state or create a new one
+ */
+static AudioState *audio_init(Audiodev *dev)
 {
+    static bool atexit_registered;
     size_t i;
     int done = 0;
     const char *drvname = NULL;
     VMChangeStateEntry *e;
-    AudioState *s = &glob_audio_state;
+    AudioState *s;
     struct audio_driver *driver;
     /* silence gcc warning about uninitialized variable */
     AudiodevListHead head = QSIMPLEQ_HEAD_INITIALIZER(head);
 
-    if (s->drv) {
-        if (dev) {
-            dolog("Cannot create more than one audio backend, sorry\n");
-            qapi_free_Audiodev(dev);
-        }
-        return -1;
-    }
-
     if (dev) {
         /* -audiodev option */
         drvname = AudiodevDriver_str(dev->driver);
+    } else if (!QTAILQ_EMPTY(&audio_states)) {
+        /*
+         * todo: check for -audiodev once we have normal audiodev selection
+         * support
+         */
+        return QTAILQ_FIRST(&audio_states);
     } else {
         /* legacy implicit initialization */
         head = audio_handle_legacy_opts();
@@ -1410,12 +1428,18 @@ static int audio_init(Audiodev *dev)
         dev = QSIMPLEQ_FIRST(&head)->dev;
         audio_validate_opts(dev, &error_abort);
     }
+
+    s = g_malloc0(sizeof(AudioState));
     s->dev = dev;
 
     QLIST_INIT (&s->hw_head_out);
     QLIST_INIT (&s->hw_head_in);
     QLIST_INIT (&s->cap_head);
-    atexit(audio_cleanup);
+    if (!atexit_registered) {
+        atexit(audio_cleanup);
+        atexit_registered = true;
+    }
+    QTAILQ_INSERT_TAIL(&audio_states, s, list);
 
     s->ts = timer_new_ns(QEMU_CLOCK_VIRTUAL, audio_timer, s);
 
@@ -1480,7 +1504,7 @@ static int audio_init(Audiodev *dev)
 
     QLIST_INIT (&s->card_head);
     vmstate_register (NULL, 0, &vmstate_audio, s);
-    return 0;
+    return s;
 }
 
 void audio_free_audiodev_list(AudiodevListHead *head)
@@ -1495,10 +1519,13 @@ void audio_free_audiodev_list(AudiodevListHead *head)
 
 void AUD_register_card (const char *name, QEMUSoundCard *card)
 {
-    audio_init(NULL);
+    if (!card->state) {
+        card->state = audio_init(NULL);
+    }
+
     card->name = g_strdup (name);
     memset (&card->entries, 0, sizeof (card->entries));
-    QLIST_INSERT_HEAD (&glob_audio_state.card_head, card, entries);
+    QLIST_INSERT_HEAD(&card->state->card_head, card, entries);
 }
 
 void AUD_remove_card (QEMUSoundCard *card)
@@ -1508,16 +1535,21 @@ void AUD_remove_card (QEMUSoundCard *card)
 }
 
 
-CaptureVoiceOut *AUD_add_capture (
+CaptureVoiceOut *AUD_add_capture(
+    AudioState *s,
     struct audsettings *as,
     struct audio_capture_ops *ops,
     void *cb_opaque
     )
 {
-    AudioState *s = &glob_audio_state;
     CaptureVoiceOut *cap;
     struct capture_callback *cb;
 
+    if (!s) {
+        /* todo: remove when we have normal audiodev selection support */
+        s = audio_init(NULL);
+    }
+
     if (audio_validate_settings (as)) {
         dolog ("Invalid settings were passed when trying to add capture\n");
         audio_print_settings (as);
@@ -1807,3 +1839,25 @@ int audio_buffer_bytes(AudiodevPerDirectionOptions *pdo,
     return audio_buffer_samples(pdo, as, def_usecs) *
         audioformat_bytes_per_sample(as->fmt);
 }
+
+AudioState *audio_state_by_name(const char *name)
+{
+    AudioState *s;
+    QTAILQ_FOREACH(s, &audio_states, list) {
+        assert(s->dev);
+        if (strcmp(name, s->dev->id) == 0) {
+            return s;
+        }
+    }
+    return NULL;
+}
+
+const char *audio_get_id(QEMUSoundCard *card)
+{
+    if (card->state) {
+        assert(card->state->dev);
+        return card->state->dev->id;
+    } else {
+        return "";
+    }
+}

audio/audio.h

@@ -78,8 +78,10 @@ typedef struct SWVoiceOut SWVoiceOut;
 typedef struct CaptureVoiceOut CaptureVoiceOut;
 typedef struct SWVoiceIn SWVoiceIn;
 
+typedef struct AudioState AudioState;
 typedef struct QEMUSoundCard {
     char *name;
+    AudioState *state;
     QLIST_ENTRY (QEMUSoundCard) entries;
 } QEMUSoundCard;
 
@@ -92,7 +94,8 @@ void AUD_log (const char *cap, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
 
 void AUD_register_card (const char *name, QEMUSoundCard *card);
 void AUD_remove_card (QEMUSoundCard *card);
-CaptureVoiceOut *AUD_add_capture (
+CaptureVoiceOut *AUD_add_capture(
+    AudioState *s,
     struct audsettings *as,
     struct audio_capture_ops *ops,
     void *opaque
@@ -160,8 +163,8 @@ static inline void *advance (void *p, int incr)
 #define audio_MAX(a, b) ((a)<(b)?(b):(a))
 #endif
 
-int wav_start_capture (CaptureState *s, const char *path, int freq,
+int wav_start_capture(AudioState *state, CaptureState *s, const char *path,
-                       int bits, int nchannels);
+                      int freq, int bits, int nchannels);
 
 bool audio_is_cleaning_up(void);
 void audio_cleanup(void);
@@ -175,4 +178,7 @@ void audio_parse_option(const char *opt);
 void audio_init_audiodevs(void);
 void audio_legacy_help(void);
 
+AudioState *audio_state_by_name(const char *name);
+const char *audio_get_id(QEMUSoundCard *card);
+
 #endif /* QEMU_AUDIO_H */

audio/audio_int.h

@@ -196,6 +196,8 @@ typedef struct AudioState {
 
     bool timer_running;
     uint64_t timer_last;
+
+    QTAILQ_ENTRY(AudioState) list;
 } AudioState;
 
 extern const struct mixeng_volume nominal_volume;

audio/audio_template.h

@@ -428,7 +428,7 @@ SW *glue (AUD_open_, TYPE) (
     struct audsettings *as
     )
 {
-    AudioState *s = &glob_audio_state;
+    AudioState *s = card->state;
     AudiodevPerDirectionOptions *pdo = glue(audio_get_pdo_, TYPE)(s->dev);
 
     if (audio_bug(__func__, !card || !name || !callback_fn || !as)) {

audio/wavcapture.c

@@ -104,8 +104,8 @@ static struct capture_ops wav_capture_ops = {
     .info = wav_capture_info
 };
 
-int wav_start_capture (CaptureState *s, const char *path, int freq,
+int wav_start_capture(AudioState *state, CaptureState *s, const char *path,
-                       int bits, int nchannels)
+                      int freq, int bits, int nchannels)
 {
     WAVState *wav;
     uint8_t hdr[] = {
@@ -170,7 +170,7 @@ int wav_start_capture (CaptureState *s, const char *path, int freq,
         goto error_free;
     }
 
-    cap = AUD_add_capture (&as, &ops, wav);
+    cap = AUD_add_capture(state, &as, &ops, wav);
     if (!cap) {
         error_report("Failed to add audio capture");
         goto error_free;

monitor/misc.c

@@ -1156,7 +1156,7 @@ static void hmp_wavcapture(Monitor *mon, const QDict *qdict)
     bits = has_bits ? bits : 16;
     nchannels = has_channels ? nchannels : 2;
 
-    if (wav_start_capture (s, path, freq, bits, nchannels)) {
+    if (wav_start_capture(NULL, s, path, freq, bits, nchannels)) {
         monitor_printf(mon, "Failed to add wave capture\n");
         g_free (s);
         return;

ui/vnc.c

@@ -1224,7 +1224,7 @@ static void audio_add(VncState *vs)
     ops.destroy = audio_capture_destroy;
     ops.capture = audio_capture;
 
-    vs->audio_cap = AUD_add_capture(&vs->as, &ops, vs);
+    vs->audio_cap = AUD_add_capture(NULL, &vs->as, &ops, vs);
     if (!vs->audio_cap) {
         error_report("Failed to add audio capture");
     }