ALSA: firewire-tascam: add hwdep interface

This commit adds hwdep interface so as the other IEEE 1394 sound devices
has.

This interface is designed for mixer/control applications. By using this
interface, an application can get information about firewire node, can
lock/unlock kernel streaming and can get notification at starting/stopping
kernel streaming.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/uapi/sound/asound.h

@@ -101,9 +101,10 @@ enum {
 	SNDRV_HWDEP_IFACE_FW_BEBOB,	/* BridgeCo BeBoB based device */
 	SNDRV_HWDEP_IFACE_FW_OXFW,	/* Oxford OXFW970/971 based device */
 	SNDRV_HWDEP_IFACE_FW_DIGI00X,	/* Digidesign Digi 002/003 family */
+	SNDRV_HWDEP_IFACE_FW_TASCAM,	/* TASCAM FireWire series */
 
 	/* Don't forget to change the following: */
-	SNDRV_HWDEP_IFACE_LAST = SNDRV_HWDEP_IFACE_FW_DIGI00X
+	SNDRV_HWDEP_IFACE_LAST = SNDRV_HWDEP_IFACE_FW_TASCAM
 };
 
 struct snd_hwdep_info {

include/uapi/sound/firewire.h

@@ -64,6 +64,7 @@ union snd_firewire_event {
 #define SNDRV_FIREWIRE_TYPE_BEBOB	3
 #define SNDRV_FIREWIRE_TYPE_OXFW	4
 #define SNDRV_FIREWIRE_TYPE_DIGI00X	5
+#define SNDRV_FIREWIRE_TYPE_TASCAM	6
 /* RME, MOTU, ... */
 
 struct snd_firewire_get_info {

sound/firewire/Kconfig

@@ -138,6 +138,7 @@ config SND_FIREWIRE_DIGI00X
 config SND_FIREWIRE_TASCAM
 	tristate "TASCAM FireWire series support"
 	select SND_FIREWIRE_LIB
+	select SND_HWDEP
 	help
 	 Say Y here to include support for TASCAM.
 	  * FW-1884

sound/firewire/tascam/Makefile

@@ -1,3 +1,3 @@
 snd-firewire-tascam-objs := tascam-proc.o amdtp-tascam.o tascam-stream.o \
-			    tascam-pcm.o tascam.o
+			    tascam-pcm.o tascam-hwdep.o tascam.o
 obj-$(CONFIG_SND_FIREWIRE_TASCAM) += snd-firewire-tascam.o

sound/firewire/tascam/tascam-hwdep.c

@@ -0,0 +1,201 @@
+/*
+ * tascam-hwdep.c - a part of driver for TASCAM FireWire series
+ *
+ * Copyright (c) 2015 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+/*
+ * This codes give three functionality.
+ *
+ * 1.get firewire node information
+ * 2.get notification about starting/stopping stream
+ * 3.lock/unlock stream
+ */
+
+#include "tascam.h"
+
+static long hwdep_read_locked(struct snd_tscm *tscm, char __user *buf,
+			      long count)
+{
+	union snd_firewire_event event;
+
+	memset(&event, 0, sizeof(event));
+
+	event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+	event.lock_status.status = (tscm->dev_lock_count > 0);
+	tscm->dev_lock_changed = false;
+
+	count = min_t(long, count, sizeof(event.lock_status));
+
+	if (copy_to_user(buf, &event, count))
+		return -EFAULT;
+
+	return count;
+}
+
+static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
+		       loff_t *offset)
+{
+	struct snd_tscm *tscm = hwdep->private_data;
+	DEFINE_WAIT(wait);
+	union snd_firewire_event event;
+
+	spin_lock_irq(&tscm->lock);
+
+	while (!tscm->dev_lock_changed) {
+		prepare_to_wait(&tscm->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
+		spin_unlock_irq(&tscm->lock);
+		schedule();
+		finish_wait(&tscm->hwdep_wait, &wait);
+		if (signal_pending(current))
+			return -ERESTARTSYS;
+		spin_lock_irq(&tscm->lock);
+	}
+
+	memset(&event, 0, sizeof(event));
+	count = hwdep_read_locked(tscm, buf, count);
+	spin_unlock_irq(&tscm->lock);
+
+	return count;
+}
+
+static unsigned int hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
+			       poll_table *wait)
+{
+	struct snd_tscm *tscm = hwdep->private_data;
+	unsigned int events;
+
+	poll_wait(file, &tscm->hwdep_wait, wait);
+
+	spin_lock_irq(&tscm->lock);
+	if (tscm->dev_lock_changed)
+		events = POLLIN | POLLRDNORM;
+	else
+		events = 0;
+	spin_unlock_irq(&tscm->lock);
+
+	return events;
+}
+
+static int hwdep_get_info(struct snd_tscm *tscm, void __user *arg)
+{
+	struct fw_device *dev = fw_parent_device(tscm->unit);
+	struct snd_firewire_get_info info;
+
+	memset(&info, 0, sizeof(info));
+	info.type = SNDRV_FIREWIRE_TYPE_TASCAM;
+	info.card = dev->card->index;
+	*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
+	*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
+	strlcpy(info.device_name, dev_name(&dev->device),
+		sizeof(info.device_name));
+
+	if (copy_to_user(arg, &info, sizeof(info)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int hwdep_lock(struct snd_tscm *tscm)
+{
+	int err;
+
+	spin_lock_irq(&tscm->lock);
+
+	if (tscm->dev_lock_count == 0) {
+		tscm->dev_lock_count = -1;
+		err = 0;
+	} else {
+		err = -EBUSY;
+	}
+
+	spin_unlock_irq(&tscm->lock);
+
+	return err;
+}
+
+static int hwdep_unlock(struct snd_tscm *tscm)
+{
+	int err;
+
+	spin_lock_irq(&tscm->lock);
+
+	if (tscm->dev_lock_count == -1) {
+		tscm->dev_lock_count = 0;
+		err = 0;
+	} else {
+		err = -EBADFD;
+	}
+
+	spin_unlock_irq(&tscm->lock);
+
+	return err;
+}
+
+static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
+{
+	struct snd_tscm *tscm = hwdep->private_data;
+
+	spin_lock_irq(&tscm->lock);
+	if (tscm->dev_lock_count == -1)
+		tscm->dev_lock_count = 0;
+	spin_unlock_irq(&tscm->lock);
+
+	return 0;
+}
+
+static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
+	    unsigned int cmd, unsigned long arg)
+{
+	struct snd_tscm *tscm = hwdep->private_data;
+
+	switch (cmd) {
+	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
+		return hwdep_get_info(tscm, (void __user *)arg);
+	case SNDRV_FIREWIRE_IOCTL_LOCK:
+		return hwdep_lock(tscm);
+	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
+		return hwdep_unlock(tscm);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
+			      unsigned int cmd, unsigned long arg)
+{
+	return hwdep_ioctl(hwdep, file, cmd,
+			   (unsigned long)compat_ptr(arg));
+}
+#else
+#define hwdep_compat_ioctl NULL
+#endif
+
+static const struct snd_hwdep_ops hwdep_ops = {
+	.read		= hwdep_read,
+	.release	= hwdep_release,
+	.poll		= hwdep_poll,
+	.ioctl		= hwdep_ioctl,
+	.ioctl_compat	= hwdep_compat_ioctl,
+};
+
+int snd_tscm_create_hwdep_device(struct snd_tscm *tscm)
+{
+	struct snd_hwdep *hwdep;
+	int err;
+
+	err = snd_hwdep_new(tscm->card, "Tascam", 0, &hwdep);
+	if (err < 0)
+		return err;
+
+	strcpy(hwdep->name, "Tascam");
+	hwdep->iface = SNDRV_HWDEP_IFACE_FW_TASCAM;
+	hwdep->ops = hwdep_ops;
+	hwdep->private_data = tscm;
+	hwdep->exclusive = true;
+
+	return err;
+}

sound/firewire/tascam/tascam-pcm.c

@@ -72,28 +72,39 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	unsigned int rate;
 	int err;
 
+	err = snd_tscm_stream_lock_try(tscm);
+	if (err < 0)
+		goto end;
+
 	err = pcm_init_hw_params(tscm, substream);
 	if (err < 0)
-		return err;
+		goto err_locked;
 
 	err = snd_tscm_stream_get_clock(tscm, &clock);
 	if (clock != SND_TSCM_CLOCK_INTERNAL ||
 	    amdtp_stream_pcm_running(&tscm->rx_stream) ||
 	    amdtp_stream_pcm_running(&tscm->tx_stream)) {
 		err = snd_tscm_stream_get_rate(tscm, &rate);
 		if (err < 0)
-			return err;
+			goto err_locked;
 		substream->runtime->hw.rate_min = rate;
 		substream->runtime->hw.rate_max = rate;
 	}
 
 	snd_pcm_set_sync(substream);
-
+end:
+	return err;
+err_locked:
+	snd_tscm_stream_lock_release(tscm);
 	return err;
 }
 
 static int pcm_close(struct snd_pcm_substream *substream)
 {
+	struct snd_tscm *tscm = substream->private_data;
+
+	snd_tscm_stream_lock_release(tscm);
+
 	return 0;
 }
 

sound/firewire/tascam/tascam-stream.c

@@ -455,3 +455,42 @@ void snd_tscm_stream_stop_duplex(struct snd_tscm *tscm)
 	finish_session(tscm);
 	release_resources(tscm);
 }
+
+void snd_tscm_stream_lock_changed(struct snd_tscm *tscm)
+{
+	tscm->dev_lock_changed = true;
+	wake_up(&tscm->hwdep_wait);
+}
+
+int snd_tscm_stream_lock_try(struct snd_tscm *tscm)
+{
+	int err;
+
+	spin_lock_irq(&tscm->lock);
+
+	/* user land lock this */
+	if (tscm->dev_lock_count < 0) {
+		err = -EBUSY;
+		goto end;
+	}
+
+	/* this is the first time */
+	if (tscm->dev_lock_count++ == 0)
+		snd_tscm_stream_lock_changed(tscm);
+	err = 0;
+end:
+	spin_unlock_irq(&tscm->lock);
+	return err;
+}
+
+void snd_tscm_stream_lock_release(struct snd_tscm *tscm)
+{
+	spin_lock_irq(&tscm->lock);
+
+	if (WARN_ON(tscm->dev_lock_count <= 0))
+		goto end;
+	if (--tscm->dev_lock_count == 0)
+		snd_tscm_stream_lock_changed(tscm);
+end:
+	spin_unlock_irq(&tscm->lock);
+}

sound/firewire/tascam/tascam.c

@@ -110,6 +110,8 @@ static int snd_tscm_probe(struct fw_unit *unit,
 	tscm->spec = (const struct snd_tscm_spec *)entry->driver_data;
 
 	mutex_init(&tscm->mutex);
+	spin_lock_init(&tscm->lock);
+	init_waitqueue_head(&tscm->hwdep_wait);
 
 	err = check_name(tscm);
 	if (err < 0)
@@ -125,6 +127,10 @@ static int snd_tscm_probe(struct fw_unit *unit,
 	if (err < 0)
 		goto error;
 
+	err = snd_tscm_create_hwdep_device(tscm);
+	if (err < 0)
+		goto error;
+
 	err = snd_card_register(card);
 	if (err < 0)
 		goto error;

sound/firewire/tascam/tascam.h

@@ -23,6 +23,8 @@
 #include <sound/info.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
+#include <sound/firewire.h>
+#include <sound/hwdep.h>
 
 #include "../lib.h"
 #include "../amdtp-stream.h"
@@ -44,6 +46,7 @@ struct snd_tscm {
 	struct fw_unit *unit;
 
 	struct mutex mutex;
+	spinlock_t lock;
 
 	const struct snd_tscm_spec *spec;
 
@@ -52,6 +55,10 @@ struct snd_tscm {
 	struct amdtp_stream tx_stream;
 	struct amdtp_stream rx_stream;
 	unsigned int substreams_counter;
+
+	int dev_lock_count;
+	bool dev_lock_changed;
+	wait_queue_head_t hwdep_wait;
 };
 
 #define TSCM_ADDR_BASE			0xffff00000000ull
@@ -97,8 +104,14 @@ void snd_tscm_stream_destroy_duplex(struct snd_tscm *tscm);
 int snd_tscm_stream_start_duplex(struct snd_tscm *tscm, unsigned int rate);
 void snd_tscm_stream_stop_duplex(struct snd_tscm *tscm);
 
+void snd_tscm_stream_lock_changed(struct snd_tscm *tscm);
+int snd_tscm_stream_lock_try(struct snd_tscm *tscm);
+void snd_tscm_stream_lock_release(struct snd_tscm *tscm);
+
 void snd_tscm_proc_init(struct snd_tscm *tscm);
 
 int snd_tscm_create_pcm_devices(struct snd_tscm *tscm);
 
+int snd_tscm_create_hwdep_device(struct snd_tscm *tscm);
+
 #endif