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author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2014-04-25 17:44:47 +0400 |
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committer | Takashi Iwai <tiwai@suse.de> | 2014-05-26 16:12:44 +0400 |
commit | 83d8d72dffa87a6dcecce229617273be62ec5bc0 (patch) | |
tree | 3eb795a28972593f9da2d4f81c05e538553551cb /sound/firewire/amdtp.h | |
parent | 2b3fc456febf540cd9bbf4c8cb4fba0dd0648df3 (diff) | |
download | linux-83d8d72dffa87a6dcecce229617273be62ec5bc0.tar.xz |
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: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire/amdtp.h')
-rw-r--r-- | sound/firewire/amdtp.h | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h index c831aaa2a811..098187d4b499 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; |