ALSA: firewire-tascam: notify events of change of state for userspace applications

In former commits, ALSA firewire-tascam driver queues events to notify change of state of control surface to userspace via ALSA hwdep interface. This commit implements actual notification of the events. The events are not governed by real time, thus no need to care underrun.

Takashi Sakamoto committed 7 years ago

Commit a8c0d131 parent afb8e2d3 files · +72 −2Browse files

Unified · Split

3 files

include/uapi/sound/firewire.h +7 −0
sound/firewire/tascam/amdtp-tascam.c +2 −0
sound/firewire/tascam/tascam-hwdep.c +63 −2

include/uapi/sound/firewire.h+7−0

 #define SNDRV_FIREWIRE_EVENT_EFW_RESPONSE	0x4e617475
 #define SNDRV_FIREWIRE_EVENT_DIGI00X_MESSAGE	0x746e736c
 #define SNDRV_FIREWIRE_EVENT_MOTU_NOTIFICATION	0x64776479
+#define SNDRV_FIREWIRE_EVENT_TASCAM_CONTROL	0x7473636d
 struct snd_firewire_event_common {
 	unsigned int type; /* SNDRV_FIREWIRE_EVENT_xxx */
 	__be32 after;
 };
+struct snd_firewire_event_tascam_control {
+	unsigned int type;
+	struct snd_firewire_tascam_change changes[0];
+};
 union snd_firewire_event {
 	struct snd_firewire_event_common            common;
 	struct snd_firewire_event_lock_status       lock_status;
 	struct snd_firewire_event_dice_notification dice_notification;
 	struct snd_firewire_event_efw_response      efw_response;
 	struct snd_firewire_event_digi00x_message   digi00x_message;
+	struct snd_firewire_event_tascam_control    tascam_control;
 	struct snd_firewire_event_motu_notification motu_notification;
 };

sound/firewire/tascam/amdtp-tascam.c+2−0

@@ -156,6 +156,8 @@ static void read_status_messages(struct amdtp_stream *s, · 155 unmodified lines
156	if (++tscm->push_pos >= SND_TSCM_QUEUE_COUNT)	156	if (++tscm->push_pos >= SND_TSCM_QUEUE_COUNT)
157	tscm->push_pos = 0;	157	tscm->push_pos = 0;
158	spin_unlock_irq(&tscm->lock);	158	spin_unlock_irq(&tscm->lock);
		159
		160	wake_up(&tscm->hwdep_wait);
159	}	161	}
160	}	162	}
161		163

sound/firewire/tascam/tascam-hwdep.c+63−2

@@ -35,6 +35,65 @@ static long tscm_hwdep_read_locked(struct snd_tscm tscm, char __user buf, · 34 unmodified lines
35	return count;	35	return count;
36	}	36	}
37		37
		38	static long tscm_hwdep_read_queue(struct snd_tscm tscm, char __user buf,
		39	long remained, loff_t *offset)
		40	{
		41	char __user *pos = buf;
		42	unsigned int type = SNDRV_FIREWIRE_EVENT_TASCAM_CONTROL;
		43	struct snd_firewire_tascam_change *entries = tscm->queue;
		44	long count;
		45
		46	// At least, one control event can be copied.
		47	if (remained < sizeof(type) + sizeof(*entries)) {
		48	spin_unlock_irq(&tscm->lock);
		49	return -EINVAL;
		50	}
		51
		52	// Copy the type field later.
		53	count = sizeof(type);
		54	remained -= sizeof(type);
		55	pos += sizeof(type);
		56
		57	while (true) {
		58	unsigned int head_pos;
		59	unsigned int tail_pos;
		60	unsigned int length;
		61
		62	if (tscm->pull_pos == tscm->push_pos)
		63	break;
		64	else if (tscm->pull_pos < tscm->push_pos)
		65	tail_pos = tscm->push_pos;
		66	else
		67	tail_pos = SND_TSCM_QUEUE_COUNT;
		68	head_pos = tscm->pull_pos;
		69
		70	length = (tail_pos - head_pos) * sizeof(*entries);
		71	if (remained < length)
		72	length = rounddown(remained, sizeof(*entries));
		73	if (length == 0)
		74	break;
		75
		76	spin_unlock_irq(&tscm->lock);
		77	if (copy_to_user(pos, &entries[head_pos], length))
		78	return -EFAULT;
		79
		80	spin_lock_irq(&tscm->lock);
		81
		82	tscm->pull_pos = tail_pos % SND_TSCM_QUEUE_COUNT;
		83
		84	count += length;
		85	remained -= length;
		86	pos += length;
		87	}
		88
		89	spin_unlock_irq(&tscm->lock);
		90
		91	if (copy_to_user(buf, &type, sizeof(type)))
		92	return -EFAULT;
		93
		94	return count;
		95	}
		96
38	static long hwdep_read(struct snd_hwdep hwdep, char __user buf, long count,	97	static long hwdep_read(struct snd_hwdep hwdep, char __user buf, long count,
39	loff_t *offset)	98	loff_t *offset)
40	{	99	{
@@ -43,7 +102,7 @@ static long hwdep_read(struct snd_hwdep hwdep, char __user buf, long count, · 2 unmodified lines
43		102
44	spin_lock_irq(&tscm->lock);	103	spin_lock_irq(&tscm->lock);
45		104
46	while (!tscm->dev_lock_changed) {	105	while (!tscm->dev_lock_changed && tscm->push_pos == tscm->pull_pos) {
47	prepare_to_wait(&tscm->hwdep_wait, &wait, TASK_INTERRUPTIBLE);	106	prepare_to_wait(&tscm->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
48	spin_unlock_irq(&tscm->lock);	107	spin_unlock_irq(&tscm->lock);
49	schedule();	108	schedule();
@@ -56,6 +115,8 @@ static long hwdep_read(struct snd_hwdep hwdep, char __user buf, long count, · 6 unmodified lines
56	// NOTE: The acquired lock should be released in callee side.	115	// NOTE: The acquired lock should be released in callee side.
57	if (tscm->dev_lock_changed) {	116	if (tscm->dev_lock_changed) {
58	count = tscm_hwdep_read_locked(tscm, buf, count, offset);	117	count = tscm_hwdep_read_locked(tscm, buf, count, offset);
		118	} else if (tscm->push_pos != tscm->pull_pos) {
		119	count = tscm_hwdep_read_queue(tscm, buf, count, offset);
59	} else {	120	} else {
60	spin_unlock_irq(&tscm->lock);	121	spin_unlock_irq(&tscm->lock);
61	count = 0;	122	count = 0;
@@ -73,7 +134,7 @@ static __poll_t hwdep_poll(struct snd_hwdep hwdep, struct file file, · 11 unmodified lines
73	poll_wait(file, &tscm->hwdep_wait, wait);	134	poll_wait(file, &tscm->hwdep_wait, wait);
74		135
75	spin_lock_irq(&tscm->lock);	136	spin_lock_irq(&tscm->lock);
76	if (tscm->dev_lock_changed)	137	if (tscm->dev_lock_changed \|\| tscm->push_pos != tscm->pull_pos)
77	events = EPOLLIN \| EPOLLRDNORM;	138	events = EPOLLIN \| EPOLLRDNORM;
78	else	139	else
79	events = 0;	140	events = 0;

ALSA: firewire-tascam: notify events of change of state for userspace applications

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