ALSA: fireworks: Add command/response functionality into hwdep interface

This commit adds two functionality for hwdep interface, adds two parameters for
this driver, add a node for proc interface.

To receive responses from devices, this driver already allocate own callback
into initial memory space in host controller. This means no one can allocate
its own callback to the address. So this driver must give a way for user
applications to receive responses.

This commit adds a functionality to receive responses via hwdep interface. The
application can receive responses to read from this interface. To achieve this,
this commit adds a buffer to queue responses. The default size of this buffer is
1024 bytes. This size can be changed to give preferrable size to
'resp_buf_size' parameter for this driver. The application should notice rest
of space in this buffer because this driver don't push responses when this
buffer has no space.

Additionaly, this commit adds a functionality to transmit commands via hwdep
interface. The application can transmit commands to write into this interface.
I note that the application can transmit one command at once, but can receive
as many responses as possible untill the user-buffer is full.

When using these interfaces, the application must keep maximum number of
sequence number in command within the number in firewire.h because this driver
uses this number to distinguish the response is against the command by the
application or this driver.

Usually responses against commands which the application transmits are pushed
into this buffer. But to enable 'resp_buf_debug' parameter for this driver, all
responses are pushed into the buffer. When using this mode, I reccomend to
expand the size of buffer.

Finally this commit adds a new node into proc interface to output status of the
buffer.

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

1 files changed, 115 insertions, 16 deletions

diff --git a/sound/firewire/fireworks/fireworks_hwdep.c b/sound/firewire/fireworks/fireworks_hwdep.c
index 1cf491dc39a3..6b50a6796d22 100644
--- a/sound/firewire/fireworks/fireworks_hwdep.c
+++ b/sound/firewire/fireworks/fireworks_hwdep.c
@@ -7,26 +7,101 @@
  */
 
 /*
- * This codes have three functionalities.
+ * This codes have five functionalities.
  *
  * 1.get information about firewire node
  * 2.get notification about starting/stopping stream
  * 3.lock/unlock streaming
+ * 4.transmit command of EFW transaction
+ * 5.receive response of EFW transaction
+ *
  */
 
 #include "fireworks.h"
 
 static long
-hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
+hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained,
+		    loff_t *offset)
+{
+	unsigned int length, till_end, type;
+	struct snd_efw_transaction *t;
+	long count = 0;
+
+	if (remained < sizeof(type) + sizeof(struct snd_efw_transaction))
+		return -ENOSPC;
+
+	/* data type is SNDRV_FIREWIRE_EVENT_EFW_RESPONSE */
+	type = SNDRV_FIREWIRE_EVENT_EFW_RESPONSE;
+	if (copy_to_user(buf, &type, sizeof(type)))
+		return -EFAULT;
+	remained -= sizeof(type);
+	buf += sizeof(type);
+
+	/* write into buffer as many responses as possible */
+	while (efw->resp_queues > 0) {
+		t = (struct snd_efw_transaction *)(efw->pull_ptr);
+		length = be32_to_cpu(t->length) * sizeof(__be32);
+
+		/* confirm enough space for this response */
+		if (remained < length)
+			break;
+
+		/* copy from ring buffer to user buffer */
+		while (length > 0) {
+			till_end = snd_efw_resp_buf_size -
+				(unsigned int)(efw->pull_ptr - efw->resp_buf);
+			till_end = min_t(unsigned int, length, till_end);
+
+			if (copy_to_user(buf, efw->pull_ptr, till_end))
+				return -EFAULT;
+
+			efw->pull_ptr += till_end;
+			if (efw->pull_ptr >= efw->resp_buf +
+					     snd_efw_resp_buf_size)
+				efw->pull_ptr = efw->resp_buf;
+
+			length -= till_end;
+			buf += till_end;
+			count += till_end;
+			remained -= till_end;
+		}
+
+		efw->resp_queues--;
+	}
+
+	return count;
+}
+
+static long
+hwdep_read_locked(struct snd_efw *efw, char __user *buf, long count,
+		  loff_t *offset)
+{
+	union snd_firewire_event event;
+
+	memset(&event, 0, sizeof(event));
+
+	event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+	event.lock_status.status = (efw->dev_lock_count > 0);
+	efw->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_efw *efw = hwdep->private_data;
 	DEFINE_WAIT(wait);
-	union snd_firewire_event event;
 
 	spin_lock_irq(&efw->lock);
 
-	while (!efw->dev_lock_changed) {
+	while ((!efw->dev_lock_changed) && (efw->resp_queues == 0)) {
 		prepare_to_wait(&efw->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
 		spin_unlock_irq(&efw->lock);
 		schedule();
@@ -36,20 +111,43 @@ hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
 		spin_lock_irq(&efw->lock);
 	}
 
-	memset(&event, 0, sizeof(event));
-	if (efw->dev_lock_changed) {
-		event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
-		event.lock_status.status = (efw->dev_lock_count > 0);
-		efw->dev_lock_changed = false;
-
-		count = min_t(long, count, sizeof(event.lock_status));
-	}
+	if (efw->dev_lock_changed)
+		count = hwdep_read_locked(efw, buf, count, offset);
+	else if (efw->resp_queues > 0)
+		count = hwdep_read_resp_buf(efw, buf, count, offset);
 
 	spin_unlock_irq(&efw->lock);
 
-	if (copy_to_user(buf, &event, count))
-		return -EFAULT;
+	return count;
+}
 
+static long
+hwdep_write(struct snd_hwdep *hwdep, const char __user *data, long count,
+	    loff_t *offset)
+{
+	struct snd_efw *efw = hwdep->private_data;
+	u32 seqnum;
+	u8 *buf;
+
+	if (count < sizeof(struct snd_efw_transaction) ||
+	    SND_EFW_RESPONSE_MAXIMUM_BYTES < count)
+		return -EINVAL;
+
+	buf = memdup_user(data, count);
+	if (IS_ERR(buf))
+		return PTR_ERR(data);
+
+	/* check seqnum is not for kernel-land */
+	seqnum = be32_to_cpu(((struct snd_efw_transaction *)buf)->seqnum);
+	if (seqnum > SND_EFW_TRANSACTION_USER_SEQNUM_MAX) {
+		count = -EINVAL;
+		goto end;
+	}
+
+	if (snd_efw_transaction_cmd(efw->unit, buf, count) < 0)
+		count = -EIO;
+end:
+	kfree(buf);
 	return count;
 }
 
@@ -62,13 +160,13 @@ hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)
 	poll_wait(file, &efw->hwdep_wait, wait);
 
 	spin_lock_irq(&efw->lock);
-	if (efw->dev_lock_changed)
+	if (efw->dev_lock_changed || (efw->resp_queues > 0))
 		events = POLLIN | POLLRDNORM;
 	else
 		events = 0;
 	spin_unlock_irq(&efw->lock);
 
-	return events;
+	return events | POLLOUT;
 }
 
 static int
@@ -174,6 +272,7 @@ hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
 
 static const struct snd_hwdep_ops hwdep_ops = {
 	.read		= hwdep_read,
+	.write		= hwdep_write,
 	.release	= hwdep_release,
 	.poll		= hwdep_poll,
 	.ioctl		= hwdep_ioctl,