From 863981e96738983919de841ec669e157e6bdaeb0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Sun, 11 Sep 2016 04:34:46 -0300
Subject: Linux-libre 4.7.1-gnu

---
 sound/firewire/tascam/tascam.c | 118 ++++++++++++++++++++++++++++-------------
 1 file changed, 82 insertions(+), 36 deletions(-)

(limited to 'sound/firewire/tascam/tascam.c')

diff --git a/sound/firewire/tascam/tascam.c b/sound/firewire/tascam/tascam.c
index e281c338e..9dc93a7eb 100644
--- a/sound/firewire/tascam/tascam.c
+++ b/sound/firewire/tascam/tascam.c
@@ -85,10 +85,8 @@ static int identify_model(struct snd_tscm *tscm)
 	return 0;
 }
 
-static void tscm_card_free(struct snd_card *card)
+static void tscm_free(struct snd_tscm *tscm)
 {
-	struct snd_tscm *tscm = card->private_data;
-
 	snd_tscm_transaction_unregister(tscm);
 	snd_tscm_stream_destroy_duplex(tscm);
 
@@ -97,44 +95,36 @@ static void tscm_card_free(struct snd_card *card)
 	mutex_destroy(&tscm->mutex);
 }
 
-static int snd_tscm_probe(struct fw_unit *unit,
-			   const struct ieee1394_device_id *entry)
+static void tscm_card_free(struct snd_card *card)
 {
-	struct snd_card *card;
-	struct snd_tscm *tscm;
+	tscm_free(card->private_data);
+}
+
+static void do_registration(struct work_struct *work)
+{
+	struct snd_tscm *tscm = container_of(work, struct snd_tscm, dwork.work);
 	int err;
 
-	/* create card */
-	err = snd_card_new(&unit->device, -1, NULL, THIS_MODULE,
-			   sizeof(struct snd_tscm), &card);
+	err = snd_card_new(&tscm->unit->device, -1, NULL, THIS_MODULE, 0,
+			   &tscm->card);
 	if (err < 0)
-		return err;
-	card->private_free = tscm_card_free;
-
-	/* initialize myself */
-	tscm = card->private_data;
-	tscm->card = card;
-	tscm->unit = fw_unit_get(unit);
-
-	mutex_init(&tscm->mutex);
-	spin_lock_init(&tscm->lock);
-	init_waitqueue_head(&tscm->hwdep_wait);
+		return;
 
 	err = identify_model(tscm);
 	if (err < 0)
 		goto error;
 
-	snd_tscm_proc_init(tscm);
-
-	err = snd_tscm_stream_init_duplex(tscm);
+	err = snd_tscm_transaction_register(tscm);
 	if (err < 0)
 		goto error;
 
-	err = snd_tscm_create_pcm_devices(tscm);
+	err = snd_tscm_stream_init_duplex(tscm);
 	if (err < 0)
 		goto error;
 
-	err = snd_tscm_transaction_register(tscm);
+	snd_tscm_proc_init(tscm);
+
+	err = snd_tscm_create_pcm_devices(tscm);
 	if (err < 0)
 		goto error;
 
@@ -146,35 +136,91 @@ static int snd_tscm_probe(struct fw_unit *unit,
 	if (err < 0)
 		goto error;
 
-	err = snd_card_register(card);
+	err = snd_card_register(tscm->card);
 	if (err < 0)
 		goto error;
 
-	dev_set_drvdata(&unit->device, tscm);
+	/*
+	 * After registered, tscm instance can be released corresponding to
+	 * releasing the sound card instance.
+	 */
+	tscm->card->private_free = tscm_card_free;
+	tscm->card->private_data = tscm;
+	tscm->registered = true;
 
-	return err;
+	return;
 error:
-	snd_card_free(card);
-	return err;
+	snd_tscm_transaction_unregister(tscm);
+	snd_tscm_stream_destroy_duplex(tscm);
+	snd_card_free(tscm->card);
+	dev_info(&tscm->unit->device,
+		 "Sound card registration failed: %d\n", err);
+}
+
+static int snd_tscm_probe(struct fw_unit *unit,
+			   const struct ieee1394_device_id *entry)
+{
+	struct snd_tscm *tscm;
+
+	/* Allocate this independent of sound card instance. */
+	tscm = kzalloc(sizeof(struct snd_tscm), GFP_KERNEL);
+	if (tscm == NULL)
+		return -ENOMEM;
+
+	/* initialize myself */
+	tscm->unit = fw_unit_get(unit);
+	dev_set_drvdata(&unit->device, tscm);
+
+	mutex_init(&tscm->mutex);
+	spin_lock_init(&tscm->lock);
+	init_waitqueue_head(&tscm->hwdep_wait);
+
+	/* Allocate and register this sound card later. */
+	INIT_DEFERRABLE_WORK(&tscm->dwork, do_registration);
+	snd_fw_schedule_registration(unit, &tscm->dwork);
+
+	return 0;
 }
 
 static void snd_tscm_update(struct fw_unit *unit)
 {
 	struct snd_tscm *tscm = dev_get_drvdata(&unit->device);
 
+	/* Postpone a workqueue for deferred registration. */
+	if (!tscm->registered)
+		snd_fw_schedule_registration(unit, &tscm->dwork);
+
 	snd_tscm_transaction_reregister(tscm);
 
-	mutex_lock(&tscm->mutex);
-	snd_tscm_stream_update_duplex(tscm);
-	mutex_unlock(&tscm->mutex);
+	/*
+	 * After registration, userspace can start packet streaming, then this
+	 * code block works fine.
+	 */
+	if (tscm->registered) {
+		mutex_lock(&tscm->mutex);
+		snd_tscm_stream_update_duplex(tscm);
+		mutex_unlock(&tscm->mutex);
+	}
 }
 
 static void snd_tscm_remove(struct fw_unit *unit)
 {
 	struct snd_tscm *tscm = dev_get_drvdata(&unit->device);
 
-	/* No need to wait for releasing card object in this context. */
-	snd_card_free_when_closed(tscm->card);
+	/*
+	 * Confirm to stop the work for registration before the sound card is
+	 * going to be released. The work is not scheduled again because bus
+	 * reset handler is not called anymore.
+	 */
+	cancel_delayed_work_sync(&tscm->dwork);
+
+	if (tscm->registered) {
+		/* No need to wait for releasing card object in this context. */
+		snd_card_free_when_closed(tscm->card);
+	} else {
+		/* Don't forget this case. */
+		tscm_free(tscm);
+	}
 }
 
 static const struct ieee1394_device_id snd_tscm_id_table[] = {
-- 
cgit v1.2.3-54-g00ecf