ALSA: bebob: Add hwdep interface

This interface is designed for mixer/control application. By using hwdep
interface, the 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>

7 files changed, 291 insertions, 7 deletions

diff --git a/sound/firewire/bebob/Makefile b/sound/firewire/bebob/Makefile
index 533718a5c1e5..78087772a022 100644
--- a/sound/firewire/bebob/Makefile
+++ b/sound/firewire/bebob/Makefile
@@ -1,4 +1,4 @@
 snd-bebob-objs := bebob_command.o bebob_stream.o bebob_proc.o bebob_midi.o \
-                  bebob_pcm.o \
+                  bebob_pcm.o bebob_hwdep.o \
                   bebob.o
 obj-m += snd-bebob.o
diff --git a/sound/firewire/bebob/bebob.c b/sound/firewire/bebob/bebob.c
index dbd12c360046..b7d70c2e4e87 100644
--- a/sound/firewire/bebob/bebob.c
+++ b/sound/firewire/bebob/bebob.c
@@ -153,6 +153,7 @@ bebob_probe(struct fw_unit *unit,
         bebob->unit = unit;
         mutex_init(&bebob->mutex);
         spin_lock_init(&bebob->lock);
+        init_waitqueue_head(&bebob->hwdep_wait);
 
         err = name_device(bebob, entry->vendor_id);
         if (err < 0)
@@ -175,6 +176,10 @@ bebob_probe(struct fw_unit *unit,
         if (err < 0)
                 goto error;
 
+        err = snd_bebob_create_hwdep_device(bebob);
+        if (err < 0)
+                goto error;
+
         err = snd_bebob_stream_init_duplex(bebob);
         if (err < 0)
                 goto error;
diff --git a/sound/firewire/bebob/bebob.h b/sound/firewire/bebob/bebob.h
index b41bb913bac5..e8a5e447ff17 100644
--- a/sound/firewire/bebob/bebob.h
+++ b/sound/firewire/bebob/bebob.h
@@ -24,6 +24,8 @@
 #include <sound/rawmidi.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
+#include <sound/firewire.h>
+#include <sound/hwdep.h>
 
 #include "../lib.h"
 #include "../fcp.h"
@@ -75,6 +77,11 @@ struct snd_bebob {
                 rx_stream_formations[SND_BEBOB_STRM_FMT_ENTRIES];
 
         int sync_input_plug;
+
+        /* for uapi */
+        int dev_lock_count;
+        bool dev_lock_changed;
+        wait_queue_head_t hwdep_wait;
 };
 
 static inline int
@@ -175,12 +182,18 @@ void snd_bebob_stream_stop_duplex(struct snd_bebob *bebob);
 void snd_bebob_stream_update_duplex(struct snd_bebob *bebob);
 void snd_bebob_stream_destroy_duplex(struct snd_bebob *bebob);
 
+void snd_bebob_stream_lock_changed(struct snd_bebob *bebob);
+int snd_bebob_stream_lock_try(struct snd_bebob *bebob);
+void snd_bebob_stream_lock_release(struct snd_bebob *bebob);
+
 void snd_bebob_proc_init(struct snd_bebob *bebob);
 
 int snd_bebob_create_midi_devices(struct snd_bebob *bebob);
 
 int snd_bebob_create_pcm_devices(struct snd_bebob *bebob);
 
+int snd_bebob_create_hwdep_device(struct snd_bebob *bebob);
+
 #define SND_BEBOB_DEV_ENTRY(vendor, model) \
 { \
         .match_flags    = IEEE1394_MATCH_VENDOR_ID | \
diff --git a/sound/firewire/bebob/bebob_hwdep.c b/sound/firewire/bebob/bebob_hwdep.c
new file mode 100644
index 000000000000..ce731f4d8b4f
--- /dev/null
+++ b/sound/firewire/bebob/bebob_hwdep.c
@@ -0,0 +1,199 @@
+/*
+ * bebob_hwdep.c - a part of driver for BeBoB based devices
+ *
+ * Copyright (c) 2013-2014 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+/*
+ * This codes give three functionality.
+ *
+ * 1.get firewire node infomation
+ * 2.get notification about starting/stopping stream
+ * 3.lock/unlock stream
+ */
+
+#include "bebob.h"
+
+static long
+hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
+           loff_t *offset)
+{
+        struct snd_bebob *bebob = hwdep->private_data;
+        DEFINE_WAIT(wait);
+        union snd_firewire_event event;
+
+        spin_lock_irq(&bebob->lock);
+
+        while (!bebob->dev_lock_changed) {
+                prepare_to_wait(&bebob->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
+                spin_unlock_irq(&bebob->lock);
+                schedule();
+                finish_wait(&bebob->hwdep_wait, &wait);
+                if (signal_pending(current))
+                        return -ERESTARTSYS;
+                spin_lock_irq(&bebob->lock);
+        }
+
+        memset(&event, 0, sizeof(event));
+        if (bebob->dev_lock_changed) {
+                event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+                event.lock_status.status = (bebob->dev_lock_count > 0);
+                bebob->dev_lock_changed = false;
+
+                count = min_t(long, count, sizeof(event.lock_status));
+        }
+
+        spin_unlock_irq(&bebob->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_bebob *bebob = hwdep->private_data;
+        unsigned int events;
+
+        poll_wait(file, &bebob->hwdep_wait, wait);
+
+        spin_lock_irq(&bebob->lock);
+        if (bebob->dev_lock_changed)
+                events = POLLIN | POLLRDNORM;
+        else
+                events = 0;
+        spin_unlock_irq(&bebob->lock);
+
+        return events;
+}
+
+static int
+hwdep_get_info(struct snd_bebob *bebob, void __user *arg)
+{
+        struct fw_device *dev = fw_parent_device(bebob->unit);
+        struct snd_firewire_get_info info;
+
+        memset(&info, 0, sizeof(info));
+        info.type = SNDRV_FIREWIRE_TYPE_BEBOB;
+        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_bebob *bebob)
+{
+        int err;
+
+        spin_lock_irq(&bebob->lock);
+
+        if (bebob->dev_lock_count == 0) {
+                bebob->dev_lock_count = -1;
+                err = 0;
+        } else {
+                err = -EBUSY;
+        }
+
+        spin_unlock_irq(&bebob->lock);
+
+        return err;
+}
+
+static int
+hwdep_unlock(struct snd_bebob *bebob)
+{
+        int err;
+
+        spin_lock_irq(&bebob->lock);
+
+        if (bebob->dev_lock_count == -1) {
+                bebob->dev_lock_count = 0;
+                err = 0;
+        } else {
+                err = -EBADFD;
+        }
+
+        spin_unlock_irq(&bebob->lock);
+
+        return err;
+}
+
+static int
+hwdep_release(struct snd_hwdep *hwdep, struct file *file)
+{
+        struct snd_bebob *bebob = hwdep->private_data;
+
+        spin_lock_irq(&bebob->lock);
+        if (bebob->dev_lock_count == -1)
+                bebob->dev_lock_count = 0;
+        spin_unlock_irq(&bebob->lock);
+
+        return 0;
+}
+
+static int
+hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
+            unsigned int cmd, unsigned long arg)
+{
+        struct snd_bebob *bebob = hwdep->private_data;
+
+        switch (cmd) {
+        case SNDRV_FIREWIRE_IOCTL_GET_INFO:
+                return hwdep_get_info(bebob, (void __user *)arg);
+        case SNDRV_FIREWIRE_IOCTL_LOCK:
+                return hwdep_lock(bebob);
+        case SNDRV_FIREWIRE_IOCTL_UNLOCK:
+                return hwdep_unlock(bebob);
+        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_bebob_create_hwdep_device(struct snd_bebob *bebob)
+{
+        struct snd_hwdep *hwdep;
+        int err;
+
+        err = snd_hwdep_new(bebob->card, "BeBoB", 0, &hwdep);
+        if (err < 0)
+                goto end;
+        strcpy(hwdep->name, "BeBoB");
+        hwdep->iface = SNDRV_HWDEP_IFACE_FW_BEBOB;
+        hwdep->ops = hwdep_ops;
+        hwdep->private_data = bebob;
+        hwdep->exclusive = true;
+end:
+        return err;
+}
+
diff --git a/sound/firewire/bebob/bebob_midi.c b/sound/firewire/bebob/bebob_midi.c
index 120a61b90c59..c04cea2c19a6 100644
--- a/sound/firewire/bebob/bebob_midi.c
+++ b/sound/firewire/bebob/bebob_midi.c
@@ -11,17 +11,35 @@
 static int midi_capture_open(struct snd_rawmidi_substream *substream)
 {
         struct snd_bebob *bebob = substream->rmidi->private_data;
+        int err;
+
+        err = snd_bebob_stream_lock_try(bebob);
+        if (err < 0)
+                goto end;
 
         atomic_inc(&bebob->capture_substreams);
-        return snd_bebob_stream_start_duplex(bebob, 0);
+        err = snd_bebob_stream_start_duplex(bebob, 0);
+        if (err < 0)
+                snd_bebob_stream_lock_release(bebob);
+end:
+        return err;
 }
 
 static int midi_playback_open(struct snd_rawmidi_substream *substream)
 {
         struct snd_bebob *bebob = substream->rmidi->private_data;
+        int err;
+
+        err = snd_bebob_stream_lock_try(bebob);
+        if (err < 0)
+                goto end;
 
         atomic_inc(&bebob->playback_substreams);
-        return snd_bebob_stream_start_duplex(bebob, 0);
+        err = snd_bebob_stream_start_duplex(bebob, 0);
+        if (err < 0)
+                snd_bebob_stream_lock_release(bebob);
+end:
+        return err;
 }
 
 static int midi_capture_close(struct snd_rawmidi_substream *substream)
@@ -31,6 +49,7 @@ static int midi_capture_close(struct snd_rawmidi_substream *substream)
         atomic_dec(&bebob->capture_substreams);
         snd_bebob_stream_stop_duplex(bebob);
 
+        snd_bebob_stream_lock_release(bebob);
         return 0;
 }
 
@@ -41,6 +60,7 @@ static int midi_playback_close(struct snd_rawmidi_substream *substream)
         atomic_dec(&bebob->playback_substreams);
         snd_bebob_stream_stop_duplex(bebob);
 
+        snd_bebob_stream_lock_release(bebob);
         return 0;
 }
 
diff --git a/sound/firewire/bebob/bebob_pcm.c b/sound/firewire/bebob/bebob_pcm.c
index 7474309dad87..9d868171db4e 100644
--- a/sound/firewire/bebob/bebob_pcm.c
+++ b/sound/firewire/bebob/bebob_pcm.c
@@ -159,13 +159,17 @@ pcm_open(struct snd_pcm_substream *substream)
         bool internal;
         int err;
 
-        err = pcm_init_hw_params(bebob, substream);
+        err = snd_bebob_stream_lock_try(bebob);
         if (err < 0)
                 goto end;
 
+        err = pcm_init_hw_params(bebob, substream);
+        if (err < 0)
+                goto err_locked;
+
         err = snd_bebob_stream_check_internal_clock(bebob, &internal);
         if (err < 0)
-                goto end;
+                goto err_locked;
 
         /*
          * When source of clock is internal or any PCM stream are running,
@@ -178,7 +182,7 @@ pcm_open(struct snd_pcm_substream *substream)
                 if (err < 0) {
                         dev_err(&bebob->unit->device,
                                 "fail to get sampling rate: %d\n", err);
-                        goto end;
+                        goto err_locked;
                 }
 
                 substream->runtime->hw.rate_min = sampling_rate;
@@ -186,14 +190,18 @@ pcm_open(struct snd_pcm_substream *substream)
         }
 
         snd_pcm_set_sync(substream);
-
 end:
         return err;
+err_locked:
+        snd_bebob_stream_lock_release(bebob);
+        return err;
 }
 
 static int
 pcm_close(struct snd_pcm_substream *substream)
 {
+        struct snd_bebob *bebob = substream->private_data;
+        snd_bebob_stream_lock_release(bebob);
         return 0;
 }
 
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c
index 46b056c8f2a8..85b4fd661787 100644
--- a/sound/firewire/bebob/bebob_stream.c
+++ b/sound/firewire/bebob/bebob_stream.c
@@ -912,3 +912,42 @@ int snd_bebob_stream_discover(struct snd_bebob *bebob)
 end:
         return err;
 }
+
+void snd_bebob_stream_lock_changed(struct snd_bebob *bebob)
+{
+        bebob->dev_lock_changed = true;
+        wake_up(&bebob->hwdep_wait);
+}
+
+int snd_bebob_stream_lock_try(struct snd_bebob *bebob)
+{
+        int err;
+
+        spin_lock_irq(&bebob->lock);
+
+        /* user land lock this */
+        if (bebob->dev_lock_count < 0) {
+                err = -EBUSY;
+                goto end;
+        }
+
+        /* this is the first time */
+        if (bebob->dev_lock_count++ == 0)
+                snd_bebob_stream_lock_changed(bebob);
+        err = 0;
+end:
+        spin_unlock_irq(&bebob->lock);
+        return err;
+}
+
+void snd_bebob_stream_lock_release(struct snd_bebob *bebob)
+{
+        spin_lock_irq(&bebob->lock);
+
+        if (WARN_ON(bebob->dev_lock_count <= 0))
+                goto end;
+        if (--bebob->dev_lock_count == 0)
+                snd_bebob_stream_lock_changed(bebob);
+end:
+        spin_unlock_irq(&bebob->lock);
+}