ALSA: fireface: rename protocol layer for former models

In a series of Fireface, later model supports different protocol
from former models.

This commit is a preparation to support both of protocols.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/fireface/ff-protocol-former.c

@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+// ff-protocol-former.c - a part of driver for RME Fireface series
+//
+// Copyright (c) 2019 Takashi Sakamoto
+//
+// Licensed under the terms of the GNU General Public License, version 2.
+
+#include <linux/delay.h>
+
+#include "ff.h"
+
+#define FF800_STF		0x0000fc88f000
+#define FF800_RX_PACKET_FORMAT	0x0000fc88f004
+#define FF800_ALLOC_TX_STREAM	0x0000fc88f008
+#define FF800_ISOC_COMM_START	0x0000fc88f00c
+#define   FF800_TX_S800_FLAG	0x00000800
+#define FF800_ISOC_COMM_STOP	0x0000fc88f010
+
+#define FF800_TX_PACKET_ISOC_CH	0x0000801c0008
+
+static int allocate_rx_resources(struct snd_ff *ff)
+{
+	u32 data;
+	__le32 reg;
+	int err;
+
+	// Controllers should allocate isochronous resources for rx stream.
+	err = fw_iso_resources_allocate(&ff->rx_resources,
+				amdtp_stream_get_max_payload(&ff->rx_stream),
+				fw_parent_device(ff->unit)->max_speed);
+	if (err < 0)
+		return err;
+
+	// Set isochronous channel and the number of quadlets of rx packets.
+	data = ff->rx_stream.data_block_quadlets << 3;
+	data = (data << 8) | ff->rx_resources.channel;
+	reg = cpu_to_le32(data);
+	return snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				FF800_RX_PACKET_FORMAT, &reg, sizeof(reg), 0);
+}
+
+static int allocate_tx_resources(struct snd_ff *ff)
+{
+	__le32 reg;
+	unsigned int count;
+	unsigned int tx_isoc_channel;
+	int err;
+
+	reg = cpu_to_le32(ff->tx_stream.data_block_quadlets);
+	err = snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 FF800_ALLOC_TX_STREAM, &reg, sizeof(reg), 0);
+	if (err < 0)
+		return err;
+
+	// Wait till the format of tx packet is available.
+	count = 0;
+	while (count++ < 10) {
+		u32 data;
+		err = snd_fw_transaction(ff->unit, TCODE_READ_QUADLET_REQUEST,
+				FF800_TX_PACKET_ISOC_CH, &reg, sizeof(reg), 0);
+		if (err < 0)
+			return err;
+
+		data = le32_to_cpu(reg);
+		if (data != 0xffffffff) {
+			tx_isoc_channel = data;
+			break;
+		}
+
+		msleep(50);
+	}
+	if (count >= 10)
+		return -ETIMEDOUT;
+
+	// NOTE: this is a makeshift to start OHCI 1394 IR context in the
+	// channel. On the other hand, 'struct fw_iso_resources.allocated' is
+	// not true and it's not deallocated at stop.
+	ff->tx_resources.channel = tx_isoc_channel;
+
+	return 0;
+}
+
+static int ff800_begin_session(struct snd_ff *ff, unsigned int rate)
+{
+	__le32 reg;
+	int err;
+
+	reg = cpu_to_le32(rate);
+	err = snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 FF800_STF, &reg, sizeof(reg), 0);
+	if (err < 0)
+		return err;
+
+	// If starting isochronous communication immediately, change of STF has
+	// no effect. In this case, the communication runs based on former STF.
+	// Let's sleep for a bit.
+	msleep(100);
+
+	err = allocate_rx_resources(ff);
+	if (err < 0)
+		return err;
+
+	err = allocate_tx_resources(ff);
+	if (err < 0)
+		return err;
+
+	reg = cpu_to_le32(0x80000000);
+	reg |= cpu_to_le32(ff->tx_stream.data_block_quadlets);
+	if (fw_parent_device(ff->unit)->max_speed == SCODE_800)
+		reg |= cpu_to_le32(FF800_TX_S800_FLAG);
+	return snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 FF800_ISOC_COMM_START, &reg, sizeof(reg), 0);
+}
+
+static void ff800_finish_session(struct snd_ff *ff)
+{
+	__le32 reg;
+
+	reg = cpu_to_le32(0x80000000);
+	snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+			   FF800_ISOC_COMM_STOP, &reg, sizeof(reg), 0);
+}
+
+static void ff800_handle_midi_msg(struct snd_ff *ff, __le32 *buf, size_t length)
+{
+	int i;
+
+	for (i = 0; i < length / 4; i++) {
+		u8 byte = le32_to_cpu(buf[i]) & 0xff;
+		struct snd_rawmidi_substream *substream;
+
+		substream = READ_ONCE(ff->tx_midi_substreams[0]);
+		if (substream)
+			snd_rawmidi_receive(substream, &byte, 1);
+	}
+}
+
+const struct snd_ff_protocol snd_ff_protocol_ff800 = {
+	.handle_midi_msg	= ff800_handle_midi_msg,
+	.begin_session		= ff800_begin_session,
+	.finish_session		= ff800_finish_session,
+};