Commit 83d8d72d authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: firewire-lib: Add support for MIDI capture/playback 



For capturing/playbacking MIDI messages, this commit adds one MIDI conformant
data channel. This data channel has multiplexed 8 MIDI data streams. So this
data channel can transfer messages from/to 8 MIDI ports.

And this commit allows to set PCM format even if AMDTP streams already start.
I suppose the case that PCM substreams are going to be joined into AMDTP
streams when AMDTP streams are already started for MIDI substreams. Each
driver must count how many PCM/MIDI substreams use AMDTP streams to stop
AMDTP streams.

There are differences between specifications about MIDI conformant data.

About the multiplexing, IEC 61883-6:2002, itself, has no information. It
describes labels and bytes for MIDI messages and refers to MMA/AMEI RP-027
for 'successfull implementation'. MMA/AMEI RP-027 describes 8 MPX-MIDI data
streams for one MIDI conformant data channel. IEC 61883-6:2005 adds
'sequence multiplexing' and apply this way and describe incompatibility
between 2002 and 2005.

So this commit applies IEC 61883-6:2005. When we find some devices compliant
to IEC 61883-6:2002, then this difference should be handles as device quirk
in additional work.

About the number of bytes in an MIDI conformant data, IEC 61883-6:2002 describe
0,1,2,3 bytes. MMA/AMEI RP-027 describes 'MIDI1.0-1x-SPEED', 'MIDI1.0-2x-SPEED',
'MIDI1.0-3x-SPEED' modes and the maximum bytes for each mode corresponds to 1,
2, 3 bytes. The 'MIDI1.0-2x/3x-SPEED' modes are accompanied with 'negotiation
procedure' and 'encapsulation details' but there is no specifications for them.

So this commit implements 'MIDI1.0-1x-SPEED' mode for playback, but allows
to pick up 1-3 bytes for capturing.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 2b3fc456

sound/firewire/amdtp.c

+45 −8
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/module.h>

#include <linux/slab.h>

#include <sound/pcm.h>

#include <sound/rawmidi.h>

#include "amdtp.h"



#define TICKS_PER_CYCLE		3072
@@ -123,9 +124,12 @@ void amdtp_stream_set_parameters(struct amdtp_stream *s, 
		[CIP_SFC_176400] = 176400,

		[CIP_SFC_192000] = 192000,

	};

	unsigned int sfc;

	unsigned int sfc, midi_channels;



	if (WARN_ON(amdtp_stream_running(s)))

	midi_channels = DIV_ROUND_UP(midi_ports, 8);



	if (WARN_ON(amdtp_stream_running(s)) ||

	    WARN_ON(midi_channels > AMDTP_MAX_CHANNELS_FOR_MIDI))

		return;



	for (sfc = 0; sfc < CIP_SFC_COUNT; ++sfc)
@@ -142,7 +146,7 @@ sfc_found: 
		pcm_channels *= 2;

	}

	s->sfc = sfc;

	s->data_block_quadlets = pcm_channels + DIV_ROUND_UP(midi_ports, 8);

	s->data_block_quadlets = pcm_channels + midi_channels;

	s->pcm_channels = pcm_channels;

	s->midi_ports = midi_ports;
@@ -200,7 +204,7 @@ static void amdtp_read_s32_dualwire(struct amdtp_stream *s, 
void amdtp_stream_set_pcm_format(struct amdtp_stream *s,

				 snd_pcm_format_t format)

{

	if (WARN_ON(amdtp_stream_running(s)))

	if (WARN_ON(amdtp_stream_pcm_running(s)))

		return;



	switch (format) {
@@ -507,11 +511,41 @@ static void amdtp_fill_pcm_silence(struct amdtp_stream *s, 
static void amdtp_fill_midi(struct amdtp_stream *s,

			    __be32 *buffer, unsigned int frames)

{

	unsigned int i;

	unsigned int f, port;

	u8 *b;



	for (f = 0; f < frames; f++) {

		buffer[s->pcm_channels + 1] = 0;

		b = (u8 *)&buffer[s->pcm_channels + 1];



	for (i = 0; i < frames; ++i)

		buffer[s->pcm_channels + i * s->data_block_quadlets] =

						cpu_to_be32(0x80000000);

		port = (s->data_block_counter + f) % 8;

		if ((s->midi[port] == NULL) ||

		    (snd_rawmidi_transmit(s->midi[port], b + 1, 1) <= 0))

			b[0] = 0x80;

		else

			b[0] = 0x81;



		buffer += s->data_block_quadlets;

	}

}



static void amdtp_pull_midi(struct amdtp_stream *s,

			    __be32 *buffer, unsigned int frames)

{

	unsigned int f, port;

	int len;

	u8 *b;



	for (f = 0; f < frames; f++) {

		port = (s->data_block_counter + f) % 8;

		b = (u8 *)&buffer[s->pcm_channels + 1];



		len = b[0] - 0x80;

		if ((1 <= len) &&  (len <= 3) && (s->midi[port]))

			snd_rawmidi_receive(s->midi[port], b + 1, len);



		buffer += s->data_block_quadlets;

	}

}



static void update_pcm_pointers(struct amdtp_stream *s,
@@ -688,6 +722,9 @@ static void handle_in_packet(struct amdtp_stream *s, 
		pcm = ACCESS_ONCE(s->pcm);

		if (pcm)

			s->transfer_samples(s, pcm, buffer, data_blocks);



		if (s->midi_ports)

			amdtp_pull_midi(s, buffer, data_blocks);

	}



	s->data_block_counter = (data_block_counter + data_blocks) & 0xff;

sound/firewire/amdtp.h

+43 −0
Original line number Diff line number Diff line
@@ -46,9 +46,21 @@ enum cip_sfc { 
#define AMDTP_OUT_PCM_FORMAT_BITS	(SNDRV_PCM_FMTBIT_S16 | \

					 SNDRV_PCM_FMTBIT_S32)





/*

 * AMDTP packet can include channels for MIDI conformant data.

 * Each MIDI conformant data channel includes 8 MPX-MIDI data stream.

 * Each MPX-MIDI data stream includes one data stream from/to MIDI ports.

 *

 * This module supports maximum 1 MIDI conformant data channels.

 * Then this AMDTP packets can transfer maximum 8 MIDI data streams.

 */

#define AMDTP_MAX_CHANNELS_FOR_MIDI	1



struct fw_unit;

struct fw_iso_context;

struct snd_pcm_substream;

struct snd_rawmidi_substream;



enum amdtp_stream_direction {

	AMDTP_OUT_STREAM = 0,
@@ -90,6 +102,8 @@ struct amdtp_stream { 
	unsigned int pcm_buffer_pointer;

	unsigned int pcm_period_pointer;

	bool pointer_flush;



	struct snd_rawmidi_substream *midi[AMDTP_MAX_CHANNELS_FOR_MIDI * 8];

};



int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
@@ -138,6 +152,17 @@ static inline bool amdtp_streaming_error(struct amdtp_stream *s) 
	return s->packet_index < 0;

}



/**

 * amdtp_stream_pcm_running - check PCM substream is running or not

 * @s: the AMDTP stream

 *

 * If this function returns true, PCM substream in the AMDTP stream is running.

 */

static inline bool amdtp_stream_pcm_running(struct amdtp_stream *s)

{

	return !!s->pcm;

}



/**

 * amdtp_stream_pcm_trigger - start/stop playback from a PCM device

 * @s: the AMDTP stream
@@ -153,6 +178,24 @@ static inline void amdtp_stream_pcm_trigger(struct amdtp_stream *s, 
	ACCESS_ONCE(s->pcm) = pcm;

}



/**

 * amdtp_stream_midi_trigger - start/stop playback/capture with a MIDI device

 * @s: the AMDTP stream

 * @port: index of MIDI port

 * @midi: the MIDI device to be started, or %NULL to stop the current device

 *

 * Call this function on a running isochronous stream to enable the actual

 * transmission of MIDI data.  This function should be called from the MIDI

 * device's .trigger callback.

 */

static inline void amdtp_stream_midi_trigger(struct amdtp_stream *s,

					     unsigned int port,

					     struct snd_rawmidi_substream *midi)

{

	if (port < s->midi_ports)

		ACCESS_ONCE(s->midi[port]) = midi;

}



static inline bool cip_sfc_is_base_44100(enum cip_sfc sfc)

{

	return sfc & 1;

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