ALSA: firewire-motu: add hwdep interface

This commit adds hwdep interface so as the other sound drivers for units
on IEEE 1394 bus have.

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>

9 files changed, 285 insertions, 7 deletions

diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index be353a78c303..fd7b561af768 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -107,9 +107,10 @@ enum {
         SNDRV_HWDEP_IFACE_FW_DIGI00X,   /* Digidesign Digi 002/003 family */
         SNDRV_HWDEP_IFACE_FW_TASCAM,    /* TASCAM FireWire series */
         SNDRV_HWDEP_IFACE_LINE6,        /* Line6 USB processors */
+        SNDRV_HWDEP_IFACE_FW_MOTU,      /* MOTU FireWire series */
 
         /* Don't forget to change the following: */
-        SNDRV_HWDEP_IFACE_LAST = SNDRV_HWDEP_IFACE_LINE6
+        SNDRV_HWDEP_IFACE_LAST = SNDRV_HWDEP_IFACE_FW_MOTU
 };
 
 struct snd_hwdep_info {
diff --git a/include/uapi/sound/firewire.h b/include/uapi/sound/firewire.h
index db79a12fcc78..59c6d81f5364 100644
--- a/include/uapi/sound/firewire.h
+++ b/include/uapi/sound/firewire.h
@@ -65,7 +65,8 @@ union snd_firewire_event {
 #define SNDRV_FIREWIRE_TYPE_OXFW        4
 #define SNDRV_FIREWIRE_TYPE_DIGI00X     5
 #define SNDRV_FIREWIRE_TYPE_TASCAM      6
-/* RME, MOTU, ... */
+#define SNDRV_FIREWIRE_TYPE_MOTU        7
+/* RME... */
 
 struct snd_firewire_get_info {
         unsigned int type; /* SNDRV_FIREWIRE_TYPE_xxx */
diff --git a/sound/firewire/motu/Makefile b/sound/firewire/motu/Makefile
index a512c1e0f49c..cc195d5a5a6e 100644
--- a/sound/firewire/motu/Makefile
+++ b/sound/firewire/motu/Makefile
@@ -1,3 +1,3 @@
 snd-firewire-motu-objs := motu.o amdtp-motu.o motu-transaction.o motu-stream.o \
-                          motu-proc.o motu-pcm.o motu-midi.o
+                          motu-proc.o motu-pcm.o motu-midi.o motu-hwdep.o
 obj-$(CONFIG_SND_FIREWIRE_MOTU) += snd-firewire-motu.o
diff --git a/sound/firewire/motu/motu-hwdep.c b/sound/firewire/motu/motu-hwdep.c
new file mode 100644
index 000000000000..e795a5219a21
--- /dev/null
+++ b/sound/firewire/motu/motu-hwdep.c
@@ -0,0 +1,192 @@
+/*
+ * motu-hwdep.c - a part of driver for MOTU FireWire series
+ *
+ * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+/*
+ * This codes have five functionalities.
+ *
+ * 1.get information about firewire node
+ * 2.get notification about starting/stopping stream
+ * 3.lock/unlock streaming
+ *
+ */
+
+#include "motu.h"
+
+static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
+                       loff_t *offset)
+{
+        struct snd_motu *motu = hwdep->private_data;
+        DEFINE_WAIT(wait);
+        union snd_firewire_event event;
+
+        spin_lock_irq(&motu->lock);
+
+        while (!motu->dev_lock_changed) {
+                prepare_to_wait(&motu->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
+                spin_unlock_irq(&motu->lock);
+                schedule();
+                finish_wait(&motu->hwdep_wait, &wait);
+                if (signal_pending(current))
+                        return -ERESTARTSYS;
+                spin_lock_irq(&motu->lock);
+        }
+
+        memset(&event, 0, sizeof(event));
+        if (motu->dev_lock_changed) {
+                event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+                event.lock_status.status = (motu->dev_lock_count > 0);
+                motu->dev_lock_changed = false;
+
+                count = min_t(long, count, sizeof(event.lock_status));
+        }
+
+        spin_unlock_irq(&motu->lock);
+
+        if (copy_to_user(buf, &event, count))
+                return -EFAULT;
+
+        return count;
+}
+
+static unsigned int hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
+                               poll_table *wait)
+{
+        struct snd_motu *motu = hwdep->private_data;
+        unsigned int events;
+
+        poll_wait(file, &motu->hwdep_wait, wait);
+
+        spin_lock_irq(&motu->lock);
+        if (motu->dev_lock_changed)
+                events = POLLIN | POLLRDNORM;
+        else
+                events = 0;
+        spin_unlock_irq(&motu->lock);
+
+        return events | POLLOUT;
+}
+
+static int hwdep_get_info(struct snd_motu *motu, void __user *arg)
+{
+        struct fw_device *dev = fw_parent_device(motu->unit);
+        struct snd_firewire_get_info info;
+
+        memset(&info, 0, sizeof(info));
+        info.type = SNDRV_FIREWIRE_TYPE_MOTU;
+        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_motu *motu)
+{
+        int err;
+
+        spin_lock_irq(&motu->lock);
+
+        if (motu->dev_lock_count == 0) {
+                motu->dev_lock_count = -1;
+                err = 0;
+        } else {
+                err = -EBUSY;
+        }
+
+        spin_unlock_irq(&motu->lock);
+
+        return err;
+}
+
+static int hwdep_unlock(struct snd_motu *motu)
+{
+        int err;
+
+        spin_lock_irq(&motu->lock);
+
+        if (motu->dev_lock_count == -1) {
+                motu->dev_lock_count = 0;
+                err = 0;
+        } else {
+                err = -EBADFD;
+        }
+
+        spin_unlock_irq(&motu->lock);
+
+        return err;
+}
+
+static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
+{
+        struct snd_motu *motu = hwdep->private_data;
+
+        spin_lock_irq(&motu->lock);
+        if (motu->dev_lock_count == -1)
+                motu->dev_lock_count = 0;
+        spin_unlock_irq(&motu->lock);
+
+        return 0;
+}
+
+static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
+            unsigned int cmd, unsigned long arg)
+{
+        struct snd_motu *motu = hwdep->private_data;
+
+        switch (cmd) {
+        case SNDRV_FIREWIRE_IOCTL_GET_INFO:
+                return hwdep_get_info(motu, (void __user *)arg);
+        case SNDRV_FIREWIRE_IOCTL_LOCK:
+                return hwdep_lock(motu);
+        case SNDRV_FIREWIRE_IOCTL_UNLOCK:
+                return hwdep_unlock(motu);
+        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
+
+int snd_motu_create_hwdep_device(struct snd_motu *motu)
+{
+        static const struct snd_hwdep_ops ops = {
+                .read           = hwdep_read,
+                .release        = hwdep_release,
+                .poll           = hwdep_poll,
+                .ioctl          = hwdep_ioctl,
+                .ioctl_compat   = hwdep_compat_ioctl,
+        };
+        struct snd_hwdep *hwdep;
+        int err;
+
+        err = snd_hwdep_new(motu->card, motu->card->driver, 0, &hwdep);
+        if (err < 0)
+                return err;
+
+        strcpy(hwdep->name, "MOTU");
+        hwdep->iface = SNDRV_HWDEP_IFACE_FW_MOTU;
+        hwdep->ops = ops;
+        hwdep->private_data = motu;
+        hwdep->exclusive = true;
+
+        return 0;
+}
diff --git a/sound/firewire/motu/motu-midi.c b/sound/firewire/motu/motu-midi.c
index f232f29589d0..e3acfcc53f4e 100644
--- a/sound/firewire/motu/motu-midi.c
+++ b/sound/firewire/motu/motu-midi.c
@@ -12,6 +12,10 @@ static int midi_capture_open(struct snd_rawmidi_substream *substream)
         struct snd_motu *motu = substream->rmidi->private_data;
         int err;
 
+        err = snd_motu_stream_lock_try(motu);
+        if (err < 0)
+                return err;
+
         mutex_lock(&motu->mutex);
 
         motu->capture_substreams++;
@@ -19,6 +23,9 @@ static int midi_capture_open(struct snd_rawmidi_substream *substream)
 
         mutex_unlock(&motu->mutex);
 
+        if (err < 0)
+                snd_motu_stream_lock_release(motu);
+
         return err;
 }
 
@@ -27,6 +34,10 @@ static int midi_playback_open(struct snd_rawmidi_substream *substream)
         struct snd_motu *motu = substream->rmidi->private_data;
         int err;
 
+        err = snd_motu_stream_lock_try(motu);
+        if (err < 0)
+                return err;
+
         mutex_lock(&motu->mutex);
 
         motu->playback_substreams++;
@@ -34,6 +45,9 @@ static int midi_playback_open(struct snd_rawmidi_substream *substream)
 
         mutex_unlock(&motu->mutex);
 
+        if (err < 0)
+                snd_motu_stream_lock_release(motu);
+
         return err;
 }
 
@@ -48,6 +62,7 @@ static int midi_capture_close(struct snd_rawmidi_substream *substream)
 
         mutex_unlock(&motu->mutex);
 
+        snd_motu_stream_lock_release(motu);
         return 0;
 }
 
@@ -62,6 +77,7 @@ static int midi_playback_close(struct snd_rawmidi_substream *substream)
 
         mutex_unlock(&motu->mutex);
 
+        snd_motu_stream_lock_release(motu);
         return 0;
 }
 
diff --git a/sound/firewire/motu/motu-pcm.c b/sound/firewire/motu/motu-pcm.c
index a50bcd6f4a63..94558f3d218b 100644
--- a/sound/firewire/motu/motu-pcm.c
+++ b/sound/firewire/motu/motu-pcm.c
@@ -159,15 +159,19 @@ static int pcm_open(struct snd_pcm_substream *substream)
         unsigned int rate;
         int err;
 
+        err = snd_motu_stream_lock_try(motu);
+        if (err < 0)
+                return err;
+
         mutex_lock(&motu->mutex);
 
         err = protocol->cache_packet_formats(motu);
         if (err < 0)
-                return err;
+                goto err_locked;
 
         err = init_hw_info(motu, substream);
         if (err < 0)
-                return err;
+                goto err_locked;
 
         /*
          * When source of clock is not internal or any PCM streams are running,
@@ -175,13 +179,13 @@ static int pcm_open(struct snd_pcm_substream *substream)
          */
         err = protocol->get_clock_source(motu, &src);
         if (err < 0)
-                return err;
+                goto err_locked;
         if (src != SND_MOTU_CLOCK_SOURCE_INTERNAL ||
             amdtp_stream_pcm_running(&motu->tx_stream) ||
             amdtp_stream_pcm_running(&motu->rx_stream)) {
                 err = protocol->get_clock_rate(motu, &rate);
                 if (err < 0)
-                        return err;
+                        goto err_locked;
                 substream->runtime->hw.rate_min = rate;
                 substream->runtime->hw.rate_max = rate;
         }
@@ -191,10 +195,18 @@ static int pcm_open(struct snd_pcm_substream *substream)
         mutex_unlock(&motu->mutex);
 
         return err;
+err_locked:
+        mutex_unlock(&motu->mutex);
+        snd_motu_stream_lock_release(motu);
+        return err;
 }
 
 static int pcm_close(struct snd_pcm_substream *substream)
 {
+        struct snd_motu *motu = substream->private_data;
+
+        snd_motu_stream_lock_release(motu);
+
         return 0;
 }
 
diff --git a/sound/firewire/motu/motu-stream.c b/sound/firewire/motu/motu-stream.c
index 911d3487f775..bd458029099e 100644
--- a/sound/firewire/motu/motu-stream.c
+++ b/sound/firewire/motu/motu-stream.c
@@ -341,3 +341,41 @@ void snd_motu_stream_destroy_duplex(struct snd_motu *motu)
         motu->playback_substreams = 0;
         motu->capture_substreams = 0;
 }
+
+static void motu_lock_changed(struct snd_motu *motu)
+{
+        motu->dev_lock_changed = true;
+        wake_up(&motu->hwdep_wait);
+}
+
+int snd_motu_stream_lock_try(struct snd_motu *motu)
+{
+        int err;
+
+        spin_lock_irq(&motu->lock);
+
+        if (motu->dev_lock_count < 0) {
+                err = -EBUSY;
+                goto out;
+        }
+
+        if (motu->dev_lock_count++ == 0)
+                motu_lock_changed(motu);
+        err = 0;
+out:
+        spin_unlock_irq(&motu->lock);
+        return err;
+}
+
+void snd_motu_stream_lock_release(struct snd_motu *motu)
+{
+        spin_lock_irq(&motu->lock);
+
+        if (WARN_ON(motu->dev_lock_count <= 0))
+                goto out;
+
+        if (--motu->dev_lock_count == 0)
+                motu_lock_changed(motu);
+out:
+        spin_unlock_irq(&motu->lock);
+}
diff --git a/sound/firewire/motu/motu.c b/sound/firewire/motu/motu.c
index d4da1377fa50..619554b9dbef 100644
--- a/sound/firewire/motu/motu.c
+++ b/sound/firewire/motu/motu.c
@@ -109,6 +109,10 @@ static void do_registration(struct work_struct *work)
                         goto error;
         }
 
+        err = snd_motu_create_hwdep_device(motu);
+        if (err < 0)
+                goto error;
+
         err = snd_card_register(motu->card);
         if (err < 0)
                 goto error;
@@ -145,6 +149,7 @@ static int motu_probe(struct fw_unit *unit,
 
         mutex_init(&motu->mutex);
         spin_lock_init(&motu->lock);
+        init_waitqueue_head(&motu->hwdep_wait);
 
         /* Allocate and register this sound card later. */
         INIT_DEFERRABLE_WORK(&motu->dwork, do_registration);
diff --git a/sound/firewire/motu/motu.h b/sound/firewire/motu/motu.h
index 338b35193001..7b1d85f29b49 100644
--- a/sound/firewire/motu/motu.h
+++ b/sound/firewire/motu/motu.h
@@ -16,12 +16,16 @@
 #include <linux/mod_devicetable.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/sched/signal.h>
 
 #include <sound/control.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/info.h>
 #include <sound/rawmidi.h>
+#include <sound/firewire.h>
+#include <sound/hwdep.h>
 
 #include "../lib.h"
 #include "../amdtp-stream.h"
@@ -62,6 +66,11 @@ struct snd_motu {
         /* For notification. */
         struct fw_address_handler async_handler;
         u32 msg;
+
+        /* For uapi */
+        int dev_lock_count;
+        bool dev_lock_changed;
+        wait_queue_head_t hwdep_wait;
 };
 
 enum snd_motu_spec_flags {
@@ -136,10 +145,14 @@ int snd_motu_stream_init_duplex(struct snd_motu *motu);
 void snd_motu_stream_destroy_duplex(struct snd_motu *motu);
 int snd_motu_stream_start_duplex(struct snd_motu *motu, unsigned int rate);
 void snd_motu_stream_stop_duplex(struct snd_motu *motu);
+int snd_motu_stream_lock_try(struct snd_motu *motu);
+void snd_motu_stream_lock_release(struct snd_motu *motu);
 
 void snd_motu_proc_init(struct snd_motu *motu);
 
 int snd_motu_create_pcm_devices(struct snd_motu *motu);
 
 int snd_motu_create_midi_devices(struct snd_motu *motu);
+
+int snd_motu_create_hwdep_device(struct snd_motu *motu);
 #endif