ALSA: firewire-motu: add message parser for meter information in command DSP model

Some of MOTU models allows software to configure their DSP parameters by
command included in asynchronous transaction. The models multiplex messages
for hardware meters into isochronous packet as well as PCM frames. For
convenience, I call them as 'command DSP' model.

This patch adds message parser for them to gather hardware meter
information.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20211015080826.34847-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 160 insertions, 0 deletions

diff --git a/sound/firewire/motu/motu-command-dsp-message-parser.c b/sound/firewire/motu/motu-command-dsp-message-parser.c
new file mode 100644
index 000000000000..6716074f8bc1
--- /dev/null
+++ b/sound/firewire/motu/motu-command-dsp-message-parser.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// motu-command-dsp-message-parser.c - a part of driver for MOTU FireWire series
+//
+// Copyright (c) 2021 Takashi Sakamoto <o-takashi@sakamocchi.jp>
+
+// Below models allow software to configure their DSP function by command transferred in
+// asynchronous transaction:
+//  * 828 mk3 (FireWire only and Hybrid)
+//  * 896 mk3 (FireWire only and Hybrid)
+//  * Ultralite mk3 (FireWire only and Hybrid)
+//  * Traveler mk3
+//  * Track 16
+//
+// Isochronous packets from the above models includes messages to report state of hardware meter.
+
+#include "motu.h"
+
+enum msg_parser_state {
+	INITIALIZED,
+	FRAGMENT_DETECTED,
+	AVAILABLE,
+};
+
+struct msg_parser {
+	enum msg_parser_state state;
+	unsigned int interval;
+	unsigned int message_count;
+	unsigned int fragment_pos;
+	unsigned int value_index;
+	u64 value;
+	struct snd_firewire_motu_command_dsp_meter meter;
+};
+
+int snd_motu_command_dsp_message_parser_new(struct snd_motu *motu)
+{
+	struct msg_parser *parser;
+
+	parser = devm_kzalloc(&motu->card->card_dev, sizeof(*parser), GFP_KERNEL);
+	if (!parser)
+		return -ENOMEM;
+	motu->message_parser = parser;
+
+	return 0;
+}
+
+int snd_motu_command_dsp_message_parser_init(struct snd_motu *motu, enum cip_sfc sfc)
+{
+	struct msg_parser *parser = motu->message_parser;
+
+	parser->state = INITIALIZED;
+
+	// All of data blocks don't have messages with meaningful information.
+	switch (sfc) {
+	case CIP_SFC_176400:
+	case CIP_SFC_192000:
+		parser->interval = 4;
+		break;
+	case CIP_SFC_88200:
+	case CIP_SFC_96000:
+		parser->interval = 2;
+		break;
+	case CIP_SFC_32000:
+	case CIP_SFC_44100:
+	case CIP_SFC_48000:
+	default:
+		parser->interval = 1;
+		break;
+	}
+
+	return 0;
+}
+
+#define FRAGMENT_POS			6
+#define MIDI_BYTE_POS			7
+#define MIDI_FLAG_POS			8
+// One value of hardware meter consists of 4 messages.
+#define FRAGMENTS_PER_VALUE		4
+#define VALUES_AT_IMAGE_END		0xffffffffffffffff
+
+void snd_motu_command_dsp_message_parser_parse(struct snd_motu *motu, const struct pkt_desc *descs,
+					unsigned int desc_count, unsigned int data_block_quadlets)
+{
+	struct msg_parser *parser = motu->message_parser;
+	unsigned int interval = parser->interval;
+	int i;
+
+	for (i = 0; i < desc_count; ++i) {
+		const struct pkt_desc *desc = descs + i;
+		__be32 *buffer = desc->ctx_payload;
+		unsigned int data_blocks = desc->data_blocks;
+		int j;
+
+		for (j = 0; j < data_blocks; ++j) {
+			u8 *b = (u8 *)buffer;
+			buffer += data_block_quadlets;
+
+			switch (parser->state) {
+			case INITIALIZED:
+			{
+				u8 fragment = b[FRAGMENT_POS];
+
+				if (fragment > 0) {
+					parser->value = fragment;
+					parser->message_count = 1;
+					parser->state = FRAGMENT_DETECTED;
+				}
+				break;
+			}
+			case FRAGMENT_DETECTED:
+			{
+				if (parser->message_count % interval == 0) {
+					u8 fragment = b[FRAGMENT_POS];
+
+					parser->value >>= 8;
+					parser->value |= (u64)fragment << 56;
+
+					if (parser->value == VALUES_AT_IMAGE_END) {
+						parser->state = AVAILABLE;
+						parser->fragment_pos = 0;
+						parser->value_index = 0;
+						parser->message_count = 0;
+					}
+				}
+				++parser->message_count;
+				break;
+			}
+			case AVAILABLE:
+			default:
+			{
+				if (parser->message_count % interval == 0) {
+					u8 fragment = b[FRAGMENT_POS];
+
+					parser->value >>= 8;
+					parser->value |= (u64)fragment << 56;
+					++parser->fragment_pos;
+
+					if (parser->fragment_pos == 4) {
+						if (parser->value_index <
+						    SNDRV_FIREWIRE_MOTU_COMMAND_DSP_METER_COUNT) {
+							u32 val = (u32)(parser->value >> 32);
+							parser->meter.data[parser->value_index] = val;
+							++parser->value_index;
+						}
+						parser->fragment_pos = 0;
+					}
+
+					if (parser->value == VALUES_AT_IMAGE_END) {
+						parser->value_index = 0;
+						parser->fragment_pos = 0;
+						parser->message_count = 0;
+					}
+				}
+				++parser->message_count;
+				break;
+			}
+			}
+		}
+	}
+}