Optionally, incoming rawmidi bytes can be put inside a frame of type snd_rawmidi_framing_tstamp_t. The main current benefit is that can enable in-kernel timestamping of incoming bytes, and that timestamp is likely to be more precise than what userspace can offer.
Tstamp type framing requires a kernel >= 5.14 and a buffer size that is a multiple of sizeof(snd_rawmidi_framing_tstamp_t). It is only available on input streams.
Signed-off-by: David Henningsson coding@diwic.se --- include/rawmidi.h | 38 +++++++++++++++++ include/sound/uapi/asound.h | 30 +++++++++++++- src/rawmidi/rawmidi.c | 83 +++++++++++++++++++++++++++++++++++++ src/rawmidi/rawmidi_hw.c | 2 + src/rawmidi/rawmidi_local.h | 2 + 5 files changed, 153 insertions(+), 2 deletions(-)
diff --git a/include/rawmidi.h b/include/rawmidi.h index d88c932c..83210181 100644 --- a/include/rawmidi.h +++ b/include/rawmidi.h @@ -79,6 +79,39 @@ typedef enum _snd_rawmidi_type { SND_RAWMIDI_TYPE_VIRTUAL } snd_rawmidi_type_t;
+/** Type of clock used with rawmidi tstamp framing */ +typedef enum _snd_rawmidi_clock { + SND_RAWMIDI_CLOCK_NONE = 0, + SND_RAWMIDI_CLOCK_REALTIME = 1, + SND_RAWMIDI_CLOCK_MONOTONIC = 2, + SND_RAWMIDI_CLOCK_MONOTONIC_RAW = 3, +} snd_rawmidi_clock_t; + +/** Enable or disable rawmidi framing */ +typedef enum _snd_rawmidi_framing { + SND_RAWMIDI_FRAMING_NONE = 0, + SND_RAWMIDI_FRAMING_TSTAMP = 1, +} snd_rawmidi_framing_t; + +#define SND_RAWMIDI_FRAME_TYPE_DEFAULT 0 + +#define SND_RAWMIDI_FRAMING_DATA_LENGTH 16 + +/** Incoming RawMidi bytes is put inside this container if tstamp type framing is enabled. */ +typedef struct _snd_rawmidi_framing_tstamp { + /** + * For now, frame_type is always SND_RAWMIDI_FRAME_TYPE_DEFAULT. + * Midi 2.0 is expected to add new types here. + * Applications are expected to skip unknown frame types. + */ + __u8 frame_type; + __u8 length; /* number of valid bytes in data field */ + __u8 reserved[2]; + __u32 tv_nsec; /* nanoseconds */ + __u64 tv_sec; /* seconds */ + __u8 data[SND_RAWMIDI_FRAMING_DATA_LENGTH]; +} snd_rawmidi_framing_tstamp_t; + int snd_rawmidi_open(snd_rawmidi_t **in_rmidi, snd_rawmidi_t **out_rmidi, const char *name, int mode); int snd_rawmidi_open_lconf(snd_rawmidi_t **in_rmidi, snd_rawmidi_t **out_rmidi, @@ -126,6 +159,11 @@ int snd_rawmidi_params_set_avail_min(snd_rawmidi_t *rmidi, snd_rawmidi_params_t size_t snd_rawmidi_params_get_avail_min(const snd_rawmidi_params_t *params); int snd_rawmidi_params_set_no_active_sensing(snd_rawmidi_t *rmidi, snd_rawmidi_params_t *params, int val); int snd_rawmidi_params_get_no_active_sensing(const snd_rawmidi_params_t *params); +int snd_rawmidi_params_set_framing_type(const snd_rawmidi_t *rawmidi, snd_rawmidi_params_t *params, snd_rawmidi_framing_t val); +snd_rawmidi_framing_t snd_rawmidi_params_get_framing_type(const snd_rawmidi_params_t *params); +int snd_rawmidi_params_set_clock_type(const snd_rawmidi_t *rawmidi, snd_rawmidi_params_t *params, snd_rawmidi_clock_t val); +snd_rawmidi_clock_t snd_rawmidi_params_get_clock_type(const snd_rawmidi_params_t *params); + int snd_rawmidi_params(snd_rawmidi_t *rmidi, snd_rawmidi_params_t * params); int snd_rawmidi_params_current(snd_rawmidi_t *rmidi, snd_rawmidi_params_t *params); size_t snd_rawmidi_status_sizeof(void); diff --git a/include/sound/uapi/asound.h b/include/sound/uapi/asound.h index ec610c27..9fe3943f 100644 --- a/include/sound/uapi/asound.h +++ b/include/sound/uapi/asound.h @@ -702,7 +702,7 @@ enum { * Raw MIDI section - /dev/snd/midi?? */
-#define SNDRV_RAWMIDI_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 1) +#define SNDRV_RAWMIDI_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 2)
enum { SNDRV_RAWMIDI_STREAM_OUTPUT = 0, @@ -728,12 +728,38 @@ struct snd_rawmidi_info { unsigned char reserved[64]; /* reserved for future use */ };
+#define SNDRV_RAWMIDI_MODE_FRAMING_MASK (7<<0) +#define SNDRV_RAWMIDI_MODE_FRAMING_SHIFT 0 +#define SNDRV_RAWMIDI_MODE_FRAMING_NONE (0<<0) +#define SNDRV_RAWMIDI_MODE_FRAMING_TSTAMP (1<<0) +#define SNDRV_RAWMIDI_MODE_CLOCK_MASK (7<<3) +#define SNDRV_RAWMIDI_MODE_CLOCK_SHIFT 3 +#define SNDRV_RAWMIDI_MODE_CLOCK_NONE (0<<3) +#define SNDRV_RAWMIDI_MODE_CLOCK_REALTIME (1<<3) +#define SNDRV_RAWMIDI_MODE_CLOCK_MONOTONIC (2<<3) +#define SNDRV_RAWMIDI_MODE_CLOCK_MONOTONIC_RAW (3<<3) + +#define SNDRV_RAWMIDI_FRAMING_DATA_LENGTH 16 + +struct snd_rawmidi_framing_tstamp { + /* For now, frame_type is always 0. Midi 2.0 is expected to add new + * types here. Applications are expected to skip unknown frame types. + */ + __u8 frame_type; + __u8 length; /* number of valid bytes in data field */ + __u8 reserved[2]; + __u32 tv_nsec; /* nanoseconds */ + __u64 tv_sec; /* seconds */ + __u8 data[SNDRV_RAWMIDI_FRAMING_DATA_LENGTH]; +} __packed; + struct snd_rawmidi_params { int stream; size_t buffer_size; /* queue size in bytes */ size_t avail_min; /* minimum avail bytes for wakeup */ unsigned int no_active_sensing: 1; /* do not send active sensing byte in close() */ - unsigned char reserved[16]; /* reserved for future use */ + unsigned int mode; /* For input data only, frame incoming data */ + unsigned char reserved[12]; /* reserved for future use */ };
struct snd_rawmidi_status { diff --git a/src/rawmidi/rawmidi.c b/src/rawmidi/rawmidi.c index 55f44821..ae4b2600 100644 --- a/src/rawmidi/rawmidi.c +++ b/src/rawmidi/rawmidi.c @@ -118,6 +118,15 @@ hw:soundwave,1,2 hw:DEV=1,CARD=soundwave,SUBDEV=2 \endcode
+\section rawmidi_framing Framing of rawmidi data + +Optionally, incoming rawmidi bytes can be put inside a frame of type snd_rawmidi_framing_tstamp_t. +The main current benefit is that can enable in-kernel timestamping of incoming bytes, and that +timestamp is likely to be more precise than what userspace can offer. + +Tstamp type framing requires a kernel >= 5.14 and a buffer size that is a multiple of +sizeof(snd_rawmidi_framing_tstamp_t). It is only available on input streams. + \section rawmidi_examples Examples
The full featured examples with cross-links: @@ -154,6 +163,7 @@ static int snd_rawmidi_params_default(snd_rawmidi_t *rawmidi, snd_rawmidi_params params->buffer_size = page_size(); params->avail_min = 1; params->no_active_sensing = 1; + params->mode = 0; return 0; }
@@ -811,6 +821,77 @@ int snd_rawmidi_params_get_no_active_sensing(const snd_rawmidi_params_t *params) return params->no_active_sensing; }
+/** + * \brief enable or disable rawmidi framing + * \param rawmidi RawMidi handle + * \param params pointer to snd_rawmidi_params_t structure + * \param val type of rawmidi framing + * \return 0 on success, otherwise a negative error code. + * + * Notable error codes: + * -EINVAL - "val" is invalid + * -ENOTSUP - Kernel is too old to support framing. + * + */ +int snd_rawmidi_params_set_framing_type(const snd_rawmidi_t *rawmidi, snd_rawmidi_params_t *params, snd_rawmidi_framing_t val) +{ + assert(rawmidi && params); + if (val > SNDRV_RAWMIDI_MODE_FRAMING_MASK >> SNDRV_RAWMIDI_MODE_FRAMING_SHIFT) + return -EINVAL; + if (val != SNDRV_RAWMIDI_MODE_FRAMING_NONE && + (rawmidi->version < SNDRV_PROTOCOL_VERSION(2, 0, 2) || rawmidi->stream != SND_RAWMIDI_STREAM_INPUT)) + return -ENOTSUP; + params->mode = (params->mode & ~SNDRV_RAWMIDI_MODE_FRAMING_MASK) + (val << SNDRV_RAWMIDI_MODE_FRAMING_SHIFT); + return 0; +} + +/** + * \brief get current framing type + * \param params pointer to snd_rawmidi_params_t structure + * \return the current type (0 = no framing, 1 = tstamp type framing) + */ +snd_rawmidi_framing_t snd_rawmidi_params_get_framing_type(const snd_rawmidi_params_t *params) +{ + assert(params); + return (params->mode & SNDRV_RAWMIDI_MODE_FRAMING_MASK) >> SNDRV_RAWMIDI_MODE_FRAMING_SHIFT; +} + +/** + * \brief sets clock type for tstamp type framing + * \param rawmidi RawMidi handle + * \param params pointer to snd_rawmidi_params_t structure + * \param val one of the SND_RAWMIDI_CLOCK_* constants + * \return 0 on success, otherwise a negative error code. + * + * Notable error codes: + * -EINVAL - "val" is invalid + * -ENOTSUP - Kernel is too old to support framing. + * + */ +int snd_rawmidi_params_set_clock_type(const snd_rawmidi_t *rawmidi, snd_rawmidi_params_t *params, snd_rawmidi_clock_t val) +{ + assert(rawmidi && params); + if (val > SNDRV_RAWMIDI_MODE_CLOCK_MASK >> SNDRV_RAWMIDI_MODE_CLOCK_SHIFT) + return -EINVAL; + if (val != SNDRV_RAWMIDI_MODE_CLOCK_NONE && + (rawmidi->version < SNDRV_PROTOCOL_VERSION(2, 0, 2) || rawmidi->stream != SND_RAWMIDI_STREAM_INPUT)) + return -ENOTSUP; + params->mode = (params->mode & ~SNDRV_RAWMIDI_MODE_CLOCK_MASK) + (val << SNDRV_RAWMIDI_MODE_CLOCK_SHIFT); + return 0; +} + +/** + * \brief get current clock type (for tstamp type framing) + * \param params pointer to snd_rawmidi_params_t structure + * \return the current clock type (one of the SND_RAWMIDI_CLOCK_* constants) + */ +snd_rawmidi_clock_t snd_rawmidi_params_get_clock_type(const snd_rawmidi_params_t *params) +{ + assert(params); + return (params->mode & SNDRV_RAWMIDI_MODE_CLOCK_MASK) >> SNDRV_RAWMIDI_MODE_CLOCK_SHIFT; +} + + /** * \brief set parameters about rawmidi stream * \param rawmidi RawMidi handle @@ -828,6 +909,7 @@ int snd_rawmidi_params(snd_rawmidi_t *rawmidi, snd_rawmidi_params_t * params) rawmidi->buffer_size = params->buffer_size; rawmidi->avail_min = params->avail_min; rawmidi->no_active_sensing = params->no_active_sensing; + rawmidi->params_mode = rawmidi->version < SNDRV_PROTOCOL_VERSION(2, 0, 2) ? 0 : params->mode; return 0; }
@@ -844,6 +926,7 @@ int snd_rawmidi_params_current(snd_rawmidi_t *rawmidi, snd_rawmidi_params_t *par params->buffer_size = rawmidi->buffer_size; params->avail_min = rawmidi->avail_min; params->no_active_sensing = rawmidi->no_active_sensing; + params->mode = rawmidi->params_mode; return 0; }
diff --git a/src/rawmidi/rawmidi_hw.c b/src/rawmidi/rawmidi_hw.c index 99927d75..6bfbc1f3 100644 --- a/src/rawmidi/rawmidi_hw.c +++ b/src/rawmidi/rawmidi_hw.c @@ -285,6 +285,7 @@ int snd_rawmidi_hw_open(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp, rmidi->poll_fd = fd; rmidi->ops = &snd_rawmidi_hw_ops; rmidi->private_data = hw; + rmidi->version = ver; hw->open++; *inputp = rmidi; } @@ -300,6 +301,7 @@ int snd_rawmidi_hw_open(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp, rmidi->poll_fd = fd; rmidi->ops = &snd_rawmidi_hw_ops; rmidi->private_data = hw; + rmidi->version = ver; hw->open++; *outputp = rmidi; } diff --git a/src/rawmidi/rawmidi_local.h b/src/rawmidi/rawmidi_local.h index 721e1ec9..c4068d7c 100644 --- a/src/rawmidi/rawmidi_local.h +++ b/src/rawmidi/rawmidi_local.h @@ -42,12 +42,14 @@ struct _snd_rawmidi { snd_rawmidi_type_t type; snd_rawmidi_stream_t stream; int mode; + int version; int poll_fd; const snd_rawmidi_ops_t *ops; void *private_data; size_t buffer_size; size_t avail_min; unsigned int no_active_sensing: 1; + int params_mode; };
int snd_rawmidi_hw_open(snd_rawmidi_t **input, snd_rawmidi_t **output,