[alsa-devel] [PATCH 06/49] firewire-lib: Add support for MIDI capture/playback
Takashi Sakamoto
o-takashi at sakamocchi.jp
Fri Apr 25 15:44:47 CEST 2014
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: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
sound/firewire/amdtp.c | 53 ++++++++++++++++++++++++++++++++++++++++++--------
sound/firewire/amdtp.h | 43 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+), 8 deletions(-)
diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index be1aabc..a4553ec 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
@@ -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];
+
+ 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];
- for (i = 0; i < frames; ++i)
- buffer[s->pcm_channels + i * s->data_block_quadlets] =
- cpu_to_be32(0x80000000);
+ 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;
diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h
index c831aaa..098187d 100644
--- a/sound/firewire/amdtp.h
+++ b/sound/firewire/amdtp.h
@@ -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,
@@ -139,6 +153,17 @@ static inline bool amdtp_streaming_error(struct amdtp_stream *s)
}
/**
+ * 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
* @pcm: the PCM device to be started, or %NULL to stop the current device
@@ -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;
--
1.8.3.2
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