[alsa-devel] [PATCH 06/17] firewire-lib: Add support for MIDI capture/playback
Takashi Sakamoto
o-takashi at sakamocchi.jp
Sat Nov 23 07:07:53 CET 2013
For capturing/playbacking MIDI message, this commit adds the functionality to
multiplex/demultiplex MIDI messages into AMDTP sream in IEC 61883-6. As a
result, the number of MIDI ports is limited by 16 ports, for my convinience.
And this commit allows to set PCM format even if AMDTP stream already starts.
I suppose the case that PCM data starts to be multiplexed/demultiplexed after
AMDTP stream is already started for MIDI. To distinguish whether PCM or MIDI
functionality starts AMDTP stream, this commit adds amdtp_stream_pcm_running()
and amdtp_stream_midi_running(). I think this is better than reference-counter.
IEC 61883-6 refers to AMEI/MMA RP-027 for implementation of MIDI conformant
data. This module implement 'MIDI1.0-1x-SPEED' mode. In the specification,
'MIDI1.0-2x/3x-SPEED' mode is defined with 'negotiation procedure' and
'encapsulation details'. But I cannot find specifications about them.
Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
sound/firewire/amdtp.c | 76 ++++++++++++++++++++++++++++++++++++++++++--------
sound/firewire/amdtp.h | 30 +++++++++++++++++++-
2 files changed, 94 insertions(+), 12 deletions(-)
diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index 456eb64..ebdaf76 100644
--- a/sound/firewire/amdtp.c
+++ b/sound/firewire/amdtp.c
@@ -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
@@ -122,9 +123,11 @@ 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)
@@ -143,7 +146,7 @@ sfc_found:
s->sfc = sfc;
s->data_block_quadlets = pcm_channels + DIV_ROUND_UP(midi_ports, 8);
s->pcm_channels = pcm_channels;
- s->midi_ports = midi_ports;
+ s->midi_channels = midi_channels;
s->syt_interval = amdtp_syt_intervals[sfc];
@@ -205,7 +208,7 @@ 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) {
@@ -566,11 +569,58 @@ 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 m, f, c, port;
+ int len;
+ u8 b[2];
+
+ for (f = 0; f < frames; f++) {
+ m = (s->data_block_counter + f) % 8;
+ for (c = 0; c < s->midi_channels; c++) {
+ b[0] = 0x80;
+ b[1] = 0x00;
+ len = 0;
+
+ port = c * 8 + m;
+ if ((s->midi[port] != NULL) &&
+ test_bit(port, &s->midi_triggered)) {
+ len = snd_rawmidi_transmit(s->midi[port],
+ b + 1, 1);
+ if (len <= 0)
+ b[1] = 0x00;
+ else
+ b[0] = 0x81;
+ }
+ buffer[s->pcm_channels + c] =
+ be32_to_cpu((b[0] << 24) | (b[1] << 16));
+ }
+ buffer += s->data_block_quadlets;
+ }
+}
- for (i = 0; i < frames; ++i)
- buffer[s->pcm_channels + i * s->data_block_quadlets] =
- cpu_to_be32(0x80000000);
+static void amdtp_pull_midi(struct amdtp_stream *s,
+ __be32 *buffer, unsigned int frames)
+{
+ unsigned int m, f, c, port;
+ int len;
+ u8 *b;
+
+ for (f = 0; f < frames; f++) {
+ m = (s->data_block_counter + f) % 8;
+ for (c = 0; c < s->midi_channels; c++) {
+ b = (u8 *)&buffer[s->pcm_channels + c];
+ if (b[0] < 0x81 || 0x83 < b[0])
+ continue;
+
+ port = c * 8 + m;
+ if ((s->midi[port] == NULL) ||
+ !test_bit(port, &s->midi_triggered))
+ continue;
+
+ len = b[0] - 0x80;
+ snd_rawmidi_receive(s->midi[port], b + 1, len);
+ }
+ buffer += s->data_block_quadlets;
+ }
}
static void check_pcm_pointer(struct amdtp_stream *s,
@@ -674,7 +724,7 @@ static void handle_out_packet(struct amdtp_stream *s, unsigned int cycle)
s->transfer_samples(s, pcm, buffer, data_blocks);
else
amdtp_fill_pcm_silence(s, buffer, data_blocks);
- if (s->midi_ports)
+ if (s->midi_channels)
amdtp_fill_midi(s, buffer, data_blocks);
s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
@@ -743,10 +793,14 @@ static void handle_in_packet(struct amdtp_stream *s,
buffer += 2;
pcm = ACCESS_ONCE(s->pcm);
- if (pcm) {
+ if (pcm)
s->transfer_samples(s, pcm, buffer, data_blocks);
+
+ if (s->midi_channels)
+ amdtp_pull_midi(s, buffer, data_blocks);
+
+ if (pcm)
check_pcm_pointer(s, pcm, data_blocks);
- }
}
static void out_stream_callback(struct fw_iso_context *context, u32 cycle,
diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h
index 6d7aa36..93489d8 100644
--- a/sound/firewire/amdtp.h
+++ b/sound/firewire/amdtp.h
@@ -44,9 +44,17 @@ enum cip_sfc {
#define AMDTP_OUT_PCM_FORMAT_BITS (SNDRV_PCM_FMTBIT_S16 | \
SNDRV_PCM_FMTBIT_S32)
+/*
+ * This module supports maximum 2 MIDI channels.
+ * Then AMDTP packets include maximum 16 MIDI streams multiplexed.
+ * This is for our convinience.
+ */
+#define AMDTP_MAX_CHANNELS_FOR_MIDI 2
+
struct fw_unit;
struct fw_iso_context;
struct snd_pcm_substream;
+struct snd_rawmidi_substream;
enum amdtp_stream_direction {
AMDTP_RECEIVE_STREAM = 0,
@@ -64,7 +72,7 @@ struct amdtp_stream {
bool dual_wire;
unsigned int data_block_quadlets;
unsigned int pcm_channels;
- unsigned int midi_ports;
+ unsigned int midi_channels;
void (*transfer_samples)(struct amdtp_stream *s,
struct snd_pcm_substream *pcm,
__be32 *buffer, unsigned int frames);
@@ -88,6 +96,9 @@ 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];
+ unsigned long midi_triggered;
};
int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
@@ -124,6 +135,12 @@ static inline bool amdtp_stream_running(struct amdtp_stream *s)
return !IS_ERR(s->context);
}
+void amdtp_stream_midi_add(struct amdtp_stream *s,
+ struct snd_rawmidi_substream *substream);
+void amdtp_stream_midi_remove(struct amdtp_stream *s,
+ struct snd_rawmidi_substream *substream);
+bool amdtp_stream_midi_running(struct amdtp_stream *s);
+
/**
* amdtp_stream_set_pcm - configure format of PCM samples
* @s: the AMDTP stream to be configured
@@ -151,6 +168,17 @@ static inline bool amdtp_streaming_error(struct amdtp_stream *s)
}
/**
+ * amdtp_stream_pcm_running - check PCM stream is running or not
+ * @s: the AMDTP stream
+ *
+ * If this function returns true, PCM stream in the stream is running.
+ */
+static inline bool amdtp_stream_pcm_running(struct amdtp_stream *s)
+{
+ return !IS_ERR_OR_NULL(s->pcm);
+}
+
+/**
* amdtp_stream_pcm_trigger - start/stop playback from a PCM device
* @s: the AMDTP stream
* @pcm: the PCM device to be started, or %NULL to stop the current device
--
1.8.3.2
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