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, 156 insertions, 20 deletions

diff --git a/sound/firewire/fireworks/fireworks_transaction.c b/sound/firewire/fireworks/fireworks_transaction.c
index aac91d8485d5..81a65ebb5f71 100644
--- a/sound/firewire/fireworks/fireworks_transaction.c
+++ b/sound/firewire/fireworks/fireworks_transaction.c
@@ -38,6 +38,9 @@
 #define ERROR_DELAY_MS 5
 #define EFC_TIMEOUT_MS 125
 
+static DEFINE_SPINLOCK(instances_lock);
+static struct snd_efw *instances[SNDRV_CARDS] = SNDRV_DEFAULT_PTR;
+
 static DEFINE_SPINLOCK(transaction_queues_lock);
 static LIST_HEAD(transaction_queues);
 
@@ -57,6 +60,14 @@ struct transaction_queue {
 	wait_queue_head_t wait;
 };
 
+int snd_efw_transaction_cmd(struct fw_unit *unit,
+			    const void *cmd, unsigned int size)
+{
+	return snd_fw_transaction(unit, TCODE_WRITE_BLOCK_REQUEST,
+				  MEMORY_SPACE_EFW_COMMAND,
+				  (void *)cmd, size, 0);
+}
+
 int snd_efw_transaction_run(struct fw_unit *unit,
 			    const void *cmd, unsigned int cmd_size,
 			    void *resp, unsigned int resp_size)
@@ -78,9 +89,7 @@ int snd_efw_transaction_run(struct fw_unit *unit,
 
 	tries = 0;
 	do {
-		ret = snd_fw_transaction(unit, TCODE_WRITE_BLOCK_REQUEST,
-					 MEMORY_SPACE_EFW_COMMAND,
-					 (void *)cmd, cmd_size, 0);
+		ret = snd_efw_transaction_cmd(t.unit, (void *)cmd, cmd_size);
 		if (ret < 0)
 			break;
 
@@ -107,27 +116,92 @@ int snd_efw_transaction_run(struct fw_unit *unit,
 }
 
 static void
-efw_response(struct fw_card *card, struct fw_request *request,
-	     int tcode, int destination, int source,
-	     int generation, unsigned long long offset,
-	     void *data, size_t length, void *callback_data)
+copy_resp_to_buf(struct snd_efw *efw, void *data, size_t length, int *rcode)
 {
-	struct fw_device *device;
-	struct transaction_queue *t;
-	unsigned long flags;
-	int rcode;
-	u32 seqnum;
+	size_t capacity, till_end;
+	struct snd_efw_transaction *t;
 
-	rcode = RCODE_TYPE_ERROR;
-	if (length < sizeof(struct snd_efw_transaction)) {
-		rcode = RCODE_DATA_ERROR;
-		goto end;
-	} else if (offset != MEMORY_SPACE_EFW_RESPONSE) {
-		rcode = RCODE_ADDRESS_ERROR;
+	spin_lock_irq(&efw->lock);
+
+	t = (struct snd_efw_transaction *)data;
+	length = min_t(size_t, t->length * sizeof(t->length), length);
+
+	if (efw->push_ptr < efw->pull_ptr)
+		capacity = (unsigned int)(efw->pull_ptr - efw->push_ptr);
+	else
+		capacity = snd_efw_resp_buf_size -
+			   (unsigned int)(efw->push_ptr - efw->pull_ptr);
+
+	/* confirm enough space for this response */
+	if (capacity < length) {
+		*rcode = RCODE_CONFLICT_ERROR;
 		goto end;
 	}
 
-	seqnum = be32_to_cpu(((struct snd_efw_transaction *)data)->seqnum);
+	/* copy to ring buffer */
+	while (length > 0) {
+		till_end = snd_efw_resp_buf_size -
+			   (unsigned int)(efw->push_ptr - efw->resp_buf);
+		till_end = min_t(unsigned int, length, till_end);
+
+		memcpy(efw->push_ptr, data, till_end);
+
+		efw->push_ptr += till_end;
+		if (efw->push_ptr >= efw->resp_buf + snd_efw_resp_buf_size)
+			efw->push_ptr = efw->resp_buf;
+
+		length -= till_end;
+		data += till_end;
+	}
+
+	/* for hwdep */
+	efw->resp_queues++;
+	wake_up(&efw->hwdep_wait);
+
+	*rcode = RCODE_COMPLETE;
+end:
+	spin_unlock_irq(&efw->lock);
+}
+
+static void
+handle_resp_for_user(struct fw_card *card, int generation, int source,
+		     void *data, size_t length, int *rcode)
+{
+	struct fw_device *device;
+	struct snd_efw *efw;
+	unsigned int i;
+
+	spin_lock_irq(&instances_lock);
+
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		efw = instances[i];
+		if (efw == NULL)
+			continue;
+		device = fw_parent_device(efw->unit);
+		if ((device->card != card) ||
+		    (device->generation != generation))
+			continue;
+		smp_rmb();	/* node id vs. generation */
+		if (device->node_id != source)
+			continue;
+
+		break;
+	}
+	if (i == SNDRV_CARDS)
+		goto end;
+
+	copy_resp_to_buf(efw, data, length, rcode);
+end:
+	spin_unlock_irq(&instances_lock);
+}
+
+static void
+handle_resp_for_kernel(struct fw_card *card, int generation, int source,
+		       void *data, size_t length, int *rcode, u32 seqnum)
+{
+	struct fw_device *device;
+	struct transaction_queue *t;
+	unsigned long flags;
 
 	spin_lock_irqsave(&transaction_queues_lock, flags);
 	list_for_each_entry(t, &transaction_queues, list) {
@@ -144,14 +218,76 @@ efw_response(struct fw_card *card, struct fw_request *request,
 			t->size = min_t(unsigned int, length, t->size);
 			memcpy(t->buf, data, t->size);
 			wake_up(&t->wait);
-			rcode = RCODE_COMPLETE;
+			*rcode = RCODE_COMPLETE;
 		}
 	}
 	spin_unlock_irqrestore(&transaction_queues_lock, flags);
+}
+
+static void
+efw_response(struct fw_card *card, struct fw_request *request,
+	     int tcode, int destination, int source,
+	     int generation, unsigned long long offset,
+	     void *data, size_t length, void *callback_data)
+{
+	int rcode, dummy;
+	u32 seqnum;
+
+	rcode = RCODE_TYPE_ERROR;
+	if (length < sizeof(struct snd_efw_transaction)) {
+		rcode = RCODE_DATA_ERROR;
+		goto end;
+	} else if (offset != MEMORY_SPACE_EFW_RESPONSE) {
+		rcode = RCODE_ADDRESS_ERROR;
+		goto end;
+	}
+
+	seqnum = be32_to_cpu(((struct snd_efw_transaction *)data)->seqnum);
+	if (seqnum > SND_EFW_TRANSACTION_USER_SEQNUM_MAX + 1) {
+		handle_resp_for_kernel(card, generation, source,
+				       data, length, &rcode, seqnum);
+		if (snd_efw_resp_buf_debug)
+			handle_resp_for_user(card, generation, source,
+					     data, length, &dummy);
+	} else {
+		handle_resp_for_user(card, generation, source,
+				     data, length, &rcode);
+	}
 end:
 	fw_send_response(card, request, rcode);
 }
 
+void snd_efw_transaction_add_instance(struct snd_efw *efw)
+{
+	unsigned int i;
+
+	spin_lock_irq(&instances_lock);
+
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (instances[i] != NULL)
+			continue;
+		instances[i] = efw;
+		break;
+	}
+
+	spin_unlock_irq(&instances_lock);
+}
+
+void snd_efw_transaction_remove_instance(struct snd_efw *efw)
+{
+	unsigned int i;
+
+	spin_lock_irq(&instances_lock);
+
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (instances[i] != efw)
+			continue;
+		instances[i] = NULL;
+	}
+
+	spin_unlock_irq(&instances_lock);
+}
+
 void snd_efw_transaction_bus_reset(struct fw_unit *unit)
 {
 	struct transaction_queue *t;