ALSA: firewire-motu: enable to read transaction cache via hwdep interface

MOTU FireWire series can transfer messages to registered address. These
messages are transferred for the status of internal clock synchronization
just after starting streams.

When the synchronization is stable, it's 0x01ffffff. Else, it's 0x05ffffff.

This commit adds a functionality for user space applications to receive
content of the message.

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

2 files changed, 28 insertions, 2 deletions

diff --git a/sound/firewire/motu/motu-hwdep.c b/sound/firewire/motu/motu-hwdep.c
index e795a5219a21..b87ccb69d597 100644
--- a/sound/firewire/motu/motu-hwdep.c
+++ b/sound/firewire/motu/motu-hwdep.c
@@ -26,7 +26,7 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
 
 	spin_lock_irq(&motu->lock);
 
-	while (!motu->dev_lock_changed) {
+	while (!motu->dev_lock_changed && motu->msg == 0) {
 		prepare_to_wait(&motu->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
 		spin_unlock_irq(&motu->lock);
 		schedule();
@@ -43,6 +43,12 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
 		motu->dev_lock_changed = false;
 
 		count = min_t(long, count, sizeof(event.lock_status));
+	} else {
+		event.motu_notification.type = SNDRV_FIREWIRE_EVENT_MOTU_NOTIFICATION;
+		event.motu_notification.message = motu->msg;
+		motu->msg = 0;
+
+		count = min_t(long, count, sizeof(event.motu_notification));
 	}
 
 	spin_unlock_irq(&motu->lock);
@@ -62,7 +68,7 @@ static unsigned int hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
 	poll_wait(file, &motu->hwdep_wait, wait);
 
 	spin_lock_irq(&motu->lock);
-	if (motu->dev_lock_changed)
+	if (motu->dev_lock_changed || motu->msg)
 		events = POLLIN | POLLRDNORM;
 	else
 		events = 0;
diff --git a/sound/firewire/motu/motu-transaction.c b/sound/firewire/motu/motu-transaction.c
index 416dd9833896..7fc30091e0de 100644
--- a/sound/firewire/motu/motu-transaction.c
+++ b/sound/firewire/motu/motu-transaction.c
@@ -50,7 +50,27 @@ static void handle_message(struct fw_card *card, struct fw_request *request,
 			   int generation, unsigned long long offset,
 			   void *data, size_t length, void *callback_data)
 {
+	struct snd_motu *motu = callback_data;
+	__be32 *buf = (__be32 *)data;
+	unsigned long flags;
+
+	if (tcode != TCODE_WRITE_QUADLET_REQUEST) {
+		fw_send_response(card, request, RCODE_COMPLETE);
+		return;
+	}
+
+	if (offset != motu->async_handler.offset || length != 4) {
+		fw_send_response(card, request, RCODE_ADDRESS_ERROR);
+		return;
+	}
+
+	spin_lock_irqsave(&motu->lock, flags);
+	motu->msg = be32_to_cpu(*buf);
+	spin_unlock_irqrestore(&motu->lock, flags);
+
 	fw_send_response(card, request, RCODE_COMPLETE);
+
+	wake_up(&motu->hwdep_wait);
 }
 
 int snd_motu_transaction_reregister(struct snd_motu *motu)