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, 21 insertions, 0 deletions

diff --git a/sound/firewire/fireworks/fireworks.c b/sound/firewire/fireworks/fireworks.c
index f8d06f5..a354d26 100644
--- a/sound/firewire/fireworks/fireworks.c
+++ b/sound/firewire/fireworks/fireworks.c
@@ -24,6 +24,8 @@ MODULE_LICENSE("GPL v2");
 static int index[SNDRV_CARDS]	= SNDRV_DEFAULT_IDX;
 static char *id[SNDRV_CARDS]	= SNDRV_DEFAULT_STR;
 static bool enable[SNDRV_CARDS]	= SNDRV_DEFAULT_ENABLE_PNP;
+unsigned int snd_efw_resp_buf_size	= 1024;
+bool snd_efw_resp_buf_debug		= false;
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "card index");
@@ -31,6 +33,11 @@ module_param_array(id, charp, NULL, 0444);
 MODULE_PARM_DESC(id, "ID string");
 module_param_array(enable, bool, NULL, 0444);
 MODULE_PARM_DESC(enable, "enable Fireworks sound card");
+module_param_named(resp_buf_size, snd_efw_resp_buf_size, uint, 0444);
+MODULE_PARM_DESC(resp_buf_size,
+		 "response buffer size (max 4096, default 1024)");
+module_param_named(resp_buf_debug, snd_efw_resp_buf_debug, bool, 0444);
+MODULE_PARM_DESC(resp_buf_debug, "store all responses to buffer");
 
 static DEFINE_MUTEX(devices_mutex);
 static DECLARE_BITMAP(devices_used, SNDRV_CARDS);
@@ -182,6 +189,7 @@ efw_card_free(struct snd_card *card)
 	}
 
 	mutex_destroy(&efw->mutex);
+	kfree(efw->resp_buf);
 }
 
 static int
@@ -219,6 +227,17 @@ efw_probe(struct fw_unit *unit,
 	spin_lock_init(&efw->lock);
 	init_waitqueue_head(&efw->hwdep_wait);
 
+	/* prepare response buffer */
+	snd_efw_resp_buf_size = clamp(snd_efw_resp_buf_size,
+				      SND_EFW_RESPONSE_MAXIMUM_BYTES, 4096U);
+	efw->resp_buf = kzalloc(snd_efw_resp_buf_size, GFP_KERNEL);
+	if (efw->resp_buf == NULL) {
+		err = -ENOMEM;
+		goto error;
+	}
+	efw->pull_ptr = efw->push_ptr = efw->resp_buf;
+	snd_efw_transaction_add_instance(efw);
+
 	err = get_hardware_info(efw);
 	if (err < 0)
 		goto error;
@@ -256,6 +275,7 @@ end:
 	mutex_unlock(&devices_mutex);
 	return err;
 error:
+	snd_efw_transaction_remove_instance(efw);
 	mutex_unlock(&devices_mutex);
 	snd_card_free(card);
 	return err;
@@ -274,6 +294,7 @@ static void efw_remove(struct fw_unit *unit)
 	struct snd_efw *efw = dev_get_drvdata(&unit->device);
 
 	snd_efw_stream_destroy_duplex(efw);
+	snd_efw_transaction_remove_instance(efw);
 
 	snd_card_disconnect(efw->card);
 	snd_card_free_when_closed(efw->card);