[alsa-devel] [PATCH 14/17] ALSA: oxfw: copy handlers of asynchronous transaction for MIDI playback

[Takashi Sakamoto]

This commit copies some functions of asynchronous transactions for MIDI
playback, to merge scs1x module. The features of payload in asynchronous
transaction are the same as captured MIDI messages.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/firewire/oxfw/oxfw-scs1x.c | 161 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)

diff --git a/sound/firewire/oxfw/oxfw-scs1x.c b/sound/firewire/oxfw/oxfw-scs1x.c
index 807009f..94477a5 100644
--- a/sound/firewire/oxfw/oxfw-scs1x.c
+++ b/sound/firewire/oxfw/oxfw-scs1x.c
@@ -18,6 +18,20 @@ struct fw_scs1x {
 	struct fw_address_handler hss_handler;
 	u8 input_escape_count;
 	struct snd_rawmidi_substream *input;
+
+	/* For MIDI playback. */
+	struct snd_rawmidi_substream *output;
+	bool output_idle;
+	u8 output_status;
+	u8 output_bytes;
+	bool output_escaped;
+	bool output_escape_high_nibble;
+	struct tasklet_struct tasklet;
+	wait_queue_head_t idle_wait;
+	u8 buffer[HSS1394_MAX_PACKET_SIZE];
+	bool transaction_running;
+	struct fw_transaction transaction;
+	struct fw_device *fw_dev;
 };
 
 static const u8 sysex_escape_prefix[] = {
@@ -106,6 +120,148 @@ end:
 	fw_send_response(card, request, rcode);
 }
 
+static void scs_write_callback(struct fw_card *card, int rcode,
+			       void *data, size_t length, void *callback_data)
+{
+	struct fw_scs1x *scs = callback_data;
+
+	if (rcode == RCODE_GENERATION)
+		;	/* TODO: retry this packet */
+
+	scs->transaction_running = false;
+	tasklet_schedule(&scs->tasklet);
+}
+
+static bool is_valid_running_status(u8 status)
+{
+	return status >= 0x80 && status <= 0xef;
+}
+
+static bool is_one_byte_cmd(u8 status)
+{
+	return status == 0xf6 ||
+	       status >= 0xf8;
+}
+
+static bool is_two_bytes_cmd(u8 status)
+{
+	return (status >= 0xc0 && status <= 0xdf) ||
+	       status == 0xf1 ||
+	       status == 0xf3;
+}
+
+static bool is_three_bytes_cmd(u8 status)
+{
+	return (status >= 0x80 && status <= 0xbf) ||
+	       (status >= 0xe0 && status <= 0xef) ||
+	       status == 0xf2;
+}
+
+static bool is_invalid_cmd(u8 status)
+{
+	return status == 0xf4 ||
+	       status == 0xf5 ||
+	       status == 0xf9 ||
+	       status == 0xfd;
+}
+
+static void scs_output_tasklet(unsigned long data)
+{
+	struct fw_scs1x *scs = (struct fw_scs1x *)data;
+	struct snd_rawmidi_substream *stream;
+	unsigned int i;
+	u8 byte;
+	int generation;
+
+	if (scs->transaction_running)
+		return;
+
+	stream = ACCESS_ONCE(scs->output);
+	if (!stream) {
+		scs->output_idle = true;
+		wake_up(&scs->idle_wait);
+		return;
+	}
+
+	i = scs->output_bytes;
+	for (;;) {
+		if (snd_rawmidi_transmit(stream, &byte, 1) != 1) {
+			scs->output_bytes = i;
+			scs->output_idle = true;
+			wake_up(&scs->idle_wait);
+			return;
+		}
+		/*
+		 * Convert from real MIDI to what I think the device expects (no
+		 * running status, one command per packet, unescaped SysExs).
+		 */
+		if (scs->output_escaped && byte < 0x80) {
+			if (scs->output_escape_high_nibble) {
+				if (i < HSS1394_MAX_PACKET_SIZE) {
+					scs->buffer[i] = byte << 4;
+					scs->output_escape_high_nibble = false;
+				}
+			} else {
+				scs->buffer[i++] |= byte & 0x0f;
+				scs->output_escape_high_nibble = true;
+			}
+		} else if (byte < 0x80) {
+			if (i == 1) {
+				if (!is_valid_running_status(
+							scs->output_status))
+					continue;
+				scs->buffer[0] = HSS1394_TAG_USER_DATA;
+				scs->buffer[i++] = scs->output_status;
+			}
+			scs->buffer[i++] = byte;
+			if ((i == 3 && is_two_bytes_cmd(scs->output_status)) ||
+			    (i == 4 && is_three_bytes_cmd(scs->output_status)))
+				break;
+			if (i == 1 + ARRAY_SIZE(sysex_escape_prefix) &&
+			    !memcmp(scs->buffer + 1, sysex_escape_prefix,
+				    ARRAY_SIZE(sysex_escape_prefix))) {
+				scs->output_escaped = true;
+				scs->output_escape_high_nibble = true;
+				i = 0;
+			}
+			if (i >= HSS1394_MAX_PACKET_SIZE)
+				i = 1;
+		} else if (byte == 0xf7) {
+			if (scs->output_escaped) {
+				if (i >= 1 && scs->output_escape_high_nibble &&
+				    scs->buffer[0] !=
+						HSS1394_TAG_CHANGE_ADDRESS)
+					break;
+			} else {
+				if (i > 1 && scs->output_status == 0xf0) {
+					scs->buffer[i++] = 0xf7;
+					break;
+				}
+			}
+			i = 1;
+			scs->output_escaped = false;
+		} else if (!is_invalid_cmd(byte) && byte < 0xf8) {
+			i = 1;
+			scs->buffer[0] = HSS1394_TAG_USER_DATA;
+			scs->buffer[i++] = byte;
+			scs->output_status = byte;
+			scs->output_escaped = false;
+			if (is_one_byte_cmd(byte))
+				break;
+		}
+	}
+	scs->output_bytes = 1;
+	scs->output_escaped = false;
+
+	scs->transaction_running = true;
+	generation = scs->fw_dev->generation;
+	smp_rmb(); /* node_id vs. generation */
+	fw_send_request(scs->fw_dev->card, &scs->transaction,
+			TCODE_WRITE_BLOCK_REQUEST, scs->fw_dev->node_id,
+			generation, scs->fw_dev->max_speed, HSS1394_ADDRESS,
+			scs->buffer, i, scs_write_callback, scs);
+}
+
 static int midi_capture_open(struct snd_rawmidi_substream *stream)
 {
 	struct fw_scs1x *scs = stream->rmidi->private_data;
@@ -169,6 +325,7 @@ int snd_oxfw_scs1x_add(struct snd_oxfw *oxfw)
 	scs = kzalloc(sizeof(struct fw_scs1x), GFP_KERNEL);
 	if (scs == NULL)
 		return -ENOMEM;
+	scs->fw_dev = fw_parent_device(oxfw->unit);
 	oxfw->spec = scs;
 
 	/* Allocate own handler for imcoming asynchronous transaction. */
@@ -198,6 +355,10 @@ int snd_oxfw_scs1x_add(struct snd_oxfw *oxfw)
 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
 			    &midi_capture_ops);
 
+	tasklet_init(&scs->tasklet, scs_output_tasklet, (unsigned long)scs);
+	init_waitqueue_head(&scs->idle_wait);
+	scs->output_idle = true;
+
 	return 0;
 err_allocated:
 	fw_core_remove_address_handler(&scs->hss_handler);
-- 
2.5.0