ALSA: firewire-motu: handle transactions specific for MOTU FireWire models

All models of MOTU FireWire series can be controlled by write transaction
to addresses in a range from 0x'ffff'f0000'0b00 to 0x'ffff'f000'0cff.

The models support asynchronous notification. This notification has 32 bit
field data, and is transferred when status of clock changes. Meaning of
the value is not enough clear yet.

Drivers can register its address to receive the notification. Write
transaction to 0x'ffff'f000'0b04 registers higher 16 bits of the address.
Write transaction to 0x'ffff'f0000'0b08 registers the rest of bits. The
address includes node ID, thus it should be registered every time of bus
reset.

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

1 files changed, 117 insertions, 0 deletions

diff --git a/sound/firewire/motu/motu-transaction.c b/sound/firewire/motu/motu-transaction.c
new file mode 100644
index 000000000000..416dd9833896
--- /dev/null
+++ b/sound/firewire/motu/motu-transaction.c
@@ -0,0 +1,117 @@
+/*
+ * motu-transaction.c - a part of driver for MOTU FireWire series
+ *
+ * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+
+#include "motu.h"
+
+#define SND_MOTU_ADDR_BASE	0xfffff0000000ULL
+#define ASYNC_ADDR_HI  0x0b04
+#define ASYNC_ADDR_LO  0x0b08
+
+int snd_motu_transaction_read(struct snd_motu *motu, u32 offset, __be32 *reg,
+			      size_t size)
+{
+	int tcode;
+
+	if (size % sizeof(__be32) > 0 || size <= 0)
+		return -EINVAL;
+	if (size == sizeof(__be32))
+		tcode = TCODE_READ_QUADLET_REQUEST;
+	else
+		tcode = TCODE_READ_BLOCK_REQUEST;
+
+	return snd_fw_transaction(motu->unit, tcode,
+				  SND_MOTU_ADDR_BASE + offset, reg, size, 0);
+}
+
+int snd_motu_transaction_write(struct snd_motu *motu, u32 offset, __be32 *reg,
+			       size_t size)
+{
+	int tcode;
+
+	if (size % sizeof(__be32) > 0 || size <= 0)
+		return -EINVAL;
+	if (size == sizeof(__be32))
+		tcode = TCODE_WRITE_QUADLET_REQUEST;
+	else
+		tcode = TCODE_WRITE_BLOCK_REQUEST;
+
+	return snd_fw_transaction(motu->unit, tcode,
+				  SND_MOTU_ADDR_BASE + offset, reg, size, 0);
+}
+
+static void handle_message(struct fw_card *card, struct fw_request *request,
+			   int tcode, int destination, int source,
+			   int generation, unsigned long long offset,
+			   void *data, size_t length, void *callback_data)
+{
+	fw_send_response(card, request, RCODE_COMPLETE);
+}
+
+int snd_motu_transaction_reregister(struct snd_motu *motu)
+{
+	struct fw_device *device = fw_parent_device(motu->unit);
+	__be32 data;
+	int err;
+
+	if (motu->async_handler.callback_data == NULL)
+		return -EINVAL;
+
+	/* Register messaging address. Block transaction is not allowed. */
+	data = cpu_to_be32((device->card->node_id << 16) |
+			   (motu->async_handler.offset >> 32));
+	err = snd_motu_transaction_write(motu, ASYNC_ADDR_HI, &data,
+					 sizeof(data));
+	if (err < 0)
+		return err;
+
+	data = cpu_to_be32(motu->async_handler.offset);
+	return snd_motu_transaction_write(motu, ASYNC_ADDR_LO, &data,
+					  sizeof(data));
+}
+
+int snd_motu_transaction_register(struct snd_motu *motu)
+{
+	static const struct fw_address_region resp_register_region = {
+		.start	= 0xffffe0000000ull,
+		.end	= 0xffffe000ffffull,
+	};
+	int err;
+
+	/* Perhaps, 4 byte messages are transferred. */
+	motu->async_handler.length = 4;
+	motu->async_handler.address_callback = handle_message;
+	motu->async_handler.callback_data = motu;
+
+	err = fw_core_add_address_handler(&motu->async_handler,
+					  &resp_register_region);
+	if (err < 0)
+		return err;
+
+	err = snd_motu_transaction_reregister(motu);
+	if (err < 0) {
+		fw_core_remove_address_handler(&motu->async_handler);
+		motu->async_handler.address_callback = NULL;
+	}
+
+	return err;
+}
+
+void snd_motu_transaction_unregister(struct snd_motu *motu)
+{
+	__be32 data;
+
+	if (motu->async_handler.address_callback != NULL)
+		fw_core_remove_address_handler(&motu->async_handler);
+	motu->async_handler.address_callback = NULL;
+
+	/* Unregister the address. */
+	data = cpu_to_be32(0x00000000);
+	snd_motu_transaction_write(motu, ASYNC_ADDR_HI, &data, sizeof(data));
+	snd_motu_transaction_write(motu, ASYNC_ADDR_LO, &data, sizeof(data));
+}