[alsa-devel] [PATCH] [22/29] ALSA: dice: get rate-dependent parameters

[Clemens Ladisch]

In preparation for sample rate selection support, read the stream
parameters that might change when running at different sample rates.

Signed-off-by: Clemens Ladisch <clemens at ladisch.de>
---
 sound/firewire/dice.c |   92 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 90 insertions(+), 2 deletions(-)

diff --git a/sound/firewire/dice.c b/sound/firewire/dice.c
index 49b47ba..e6bba6d 100644
--- a/sound/firewire/dice.c
+++ b/sound/firewire/dice.c
@@ -6,10 +6,12 @@
  */

 #include <linux/compat.h>
+#include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/firewire.h>
 #include <linux/firewire-constants.h>
+#include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/mutex.h>
@@ -37,11 +39,14 @@ struct dice {
 	unsigned int global_offset;
 	unsigned int rx_offset;
 	unsigned int clock_caps;
+	unsigned int rx_channels[3];
+	unsigned int rx_midi_ports[3];
 	struct fw_address_handler notification_handler;
 	int owner_generation;
 	int dev_lock_count; /* > 0 driver, < 0 userspace */
 	bool dev_lock_changed;
 	bool global_enabled;
+	struct completion clock_accepted;
 	wait_queue_head_t hwdep_wait;
 	u32 notification_bits;
 	struct fw_iso_resources resources;
@@ -53,15 +58,23 @@ MODULE_AUTHOR("Clemens Ladisch <clemens at ladisch.de>");
 MODULE_LICENSE("GPL v2");

 static const unsigned int dice_rates[] = {
+	/* mode 0 */
 	[0] =  32000,
 	[1] =  44100,
 	[2] =  48000,
+	/* mode 1 */
 	[3] =  88200,
 	[4] =  96000,
+	/* mode 2 */
 	[5] = 176400,
 	[6] = 192000,
 };

+static unsigned int rate_index_to_mode(unsigned int rate_index)
+{
+	return ((int)rate_index - 1) / 2;
+}
+
 static void dice_lock_changed(struct dice *dice)
 {
 	dice->dev_lock_changed = true;
@@ -264,6 +277,7 @@ static void dice_notification(struct fw_card *card, struct fw_request *request,
 			      void *data, size_t length, void *callback_data)
 {
 	struct dice *dice = callback_data;
+	u32 bits;
 	unsigned long flags;

 	if (tcode != TCODE_WRITE_QUADLET_REQUEST) {
@@ -274,10 +288,17 @@ static void dice_notification(struct fw_card *card, struct fw_request *request,
 		fw_send_response(card, request, RCODE_ADDRESS_ERROR);
 		return;
 	}
+
+	bits = be32_to_cpup(data);
+
 	spin_lock_irqsave(&dice->lock, flags);
-	dice->notification_bits |= be32_to_cpup(data);
+	dice->notification_bits |= bits;
 	spin_unlock_irqrestore(&dice->lock, flags);
+
 	fw_send_response(card, request, RCODE_COMPLETE);
+
+	if (bits & NOTIFY_CLOCK_ACCEPTED)
+		complete(&dice->clock_accepted);
 	wake_up(&dice->hwdep_wait);
 }

@@ -457,6 +478,26 @@ static void dice_stream_stop(struct dice *dice)
 	fw_iso_resources_free(&dice->resources);
 }

+static int dice_change_rate(struct dice *dice, unsigned int clock_rate)
+{
+	__be32 value;
+	int err;
+
+	INIT_COMPLETION(dice->clock_accepted);
+
+	value = cpu_to_be32(clock_rate | CLOCK_SOURCE_ARX1);
+	err = snd_fw_transaction(dice->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 global_address(dice, GLOBAL_CLOCK_SELECT),
+				 &value, 4, 0);
+	if (err < 0)
+		return err;
+
+	wait_for_completion_timeout(&dice->clock_accepted,
+				    msecs_to_jiffies(100));
+
+	return 0;
+}
+
 static int dice_hw_params(struct snd_pcm_substream *substream,
 			  struct snd_pcm_hw_params *hw_params)
 {
@@ -831,11 +872,51 @@ static int dice_interface_check(struct fw_unit *unit)
 	return 0;
 }

+static int highest_supported_mode_rate(struct dice *dice, unsigned int mode)
+{
+	int i;
+
+	for (i = ARRAY_SIZE(dice_rates) - 1; i >= 0; --i)
+		if ((dice->clock_caps & (1 << i)) &&
+		    rate_index_to_mode(i) == mode)
+			return i;
+
+	return -1;
+}
+
+static int dice_read_mode_params(struct dice *dice, unsigned int mode)
+{
+	__be32 values[2];
+	int rate_index, err;
+
+	rate_index = highest_supported_mode_rate(dice, mode);
+	if (rate_index < 0) {
+		dice->rx_channels[mode] = 0;
+		dice->rx_midi_ports[mode] = 0;
+		return 0;
+	}
+
+	err = dice_change_rate(dice, rate_index << CLOCK_RATE_SHIFT);
+	if (err < 0)
+		return err;
+
+	err = snd_fw_transaction(dice->unit, TCODE_READ_BLOCK_REQUEST,
+				 rx_address(dice, RX_NUMBER_AUDIO),
+				 values, 2 * 4, 0);
+	if (err < 0)
+		return err;
+
+	dice->rx_channels[mode]   = be32_to_cpu(values[0]);
+	dice->rx_midi_ports[mode] = be32_to_cpu(values[1]);
+
+	return 0;
+}
+
 static int dice_read_params(struct dice *dice)
 {
 	__be32 pointers[6];
 	__be32 value;
-	int err;
+	int mode, err;

 	err = snd_fw_transaction(dice->unit, TCODE_READ_BLOCK_REQUEST,
 				 DICE_PRIVATE_SPACE,
@@ -863,6 +944,12 @@ static int dice_read_params(struct dice *dice)
 				   CLOCK_CAP_SOURCE_INTERNAL;
 	}

+	for (mode = 2; mode >= 0; --mode) {
+		err = dice_read_mode_params(dice, mode);
+		if (err < 0)
+			return err;
+	}
+
 	return 0;
 }

@@ -922,6 +1009,7 @@ static int dice_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
 	spin_lock_init(&dice->lock);
 	mutex_init(&dice->mutex);
 	dice->unit = unit;
+	init_completion(&dice->clock_accepted);
 	init_waitqueue_head(&dice->hwdep_wait);

 	dice->notification_handler.length = 4;