Commit aed713bf authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: fireface: add helper function to parse MIDI messages transmitted by Fireface 400 



This is minor code refactoring to add helper function to parse MIDI message
bytes in quadlet message.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230112120954.500692-4-o-takashi@sakamocchi.jp


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 4bdcb8d2

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

+20 −27
Original line number Diff line number Diff line
@@ -534,6 +534,22 @@ static void ff400_finish_session(struct snd_ff *ff) 
			   FF400_ISOC_COMM_STOP, &reg, sizeof(reg), 0);

}



static void parse_midi_msg(struct snd_ff *ff, u32 quad, unsigned int port)

{

	struct snd_rawmidi_substream *substream = READ_ONCE(ff->tx_midi_substreams[port]);



	if (substream != NULL) {

		u8 byte = (quad >> (16 * port)) & 0x000000ff;



		snd_rawmidi_receive(substream, &byte, 1);

	}

}



#define FF400_MSG_FLAG_IS_MIDI_PORT_0		0x00000100

#define  FF400_MSG_MASK_MIDI_PORT_0		0x000000ff

#define FF400_MSG_FLAG_IS_MIDI_PORT_1		0x01000000

#define  FF400_MSG_MASK_MIDI_PORT_1		0x00ff0000



// For Fireface 400, lower 4 bytes of destination address is configured by bit

// flag in quadlet register (little endian) at 0x'0000'801'0051c. Drivers can

// select one of 4 options:
@@ -560,34 +576,11 @@ static void ff400_handle_msg(struct snd_ff *ff, unsigned int offset, const __le3 


	for (i = 0; i < length / 4; i++) {

		u32 quad = le32_to_cpu(buf[i]);

		u8 byte;

		unsigned int index;

		struct snd_rawmidi_substream *substream;



		/* Message in first port. */

		/*

		 * This value may represent the index of this unit when the same

		 * units are on the same IEEE 1394 bus. This driver doesn't use

		 * it.

		 */

		index = (quad >> 8) & 0xff;

		if (index > 0) {

			substream = READ_ONCE(ff->tx_midi_substreams[0]);

			if (substream != NULL) {

				byte = quad & 0xff;

				snd_rawmidi_receive(substream, &byte, 1);

			}

		}



		/* Message in second port. */

		index = (quad >> 24) & 0xff;

		if (index > 0) {

			substream = READ_ONCE(ff->tx_midi_substreams[1]);

			if (substream != NULL) {

				byte = (quad >> 16) & 0xff;

				snd_rawmidi_receive(substream, &byte, 1);

			}

		}

		if (quad & FF400_MSG_FLAG_IS_MIDI_PORT_0)

			parse_midi_msg(ff, quad, 0);

		else if (quad & FF400_MSG_FLAG_IS_MIDI_PORT_1)

			parse_midi_msg(ff, quad, 1);

	}

}