We introduce a new ioctl, START_AT, and 3 new snd_pcm_fast_ops_t members.
The ioctl takes a struct snd_start_at, which holds the required operation, and corresponding arguments (which can be input and output).
The START_AT ioctol supports SET, CANCEL, and STATUS operations. STATUS returns the current time.
struct snd_start_at packing, ioctl invocation, and unpacking is implemented in pcm_hw.c.
Signed-off-by: Tim Cussins timcussins@eml.cc
diff --git a/include/sound/asound.h b/include/sound/asound.h index 1f23cd6..ab7c05b 100644 --- a/include/sound/asound.h +++ b/include/sound/asound.h @@ -420,7 +420,10 @@ struct snd_pcm_status { snd_pcm_state_t suspended_state; /* suspended stream state */ __u32 reserved_alignment; /* must be filled with zero */ struct timespec audio_tstamp; /* from sample counter or wall clock */ - unsigned char reserved[56-sizeof(struct timespec)]; /* must be filled with zero */ + int start_at_pending; + int start_at_clock_type; + struct timespec start_at_start_time; + unsigned char reserved[48-2*(sizeof(struct timespec))]; /* must be filled with zero */ };
struct snd_pcm_mmap_status { @@ -472,6 +475,34 @@ enum { SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW, };
+enum { + SNDRV_PCM_STARTAT_OP_SET = 0, + SNDRV_PCM_STARTAT_OP_CANCEL, + SNDRV_PCM_STARTAT_OP_STATUS, + SNDRV_PCM_STARTAT_OP_LAST = SNDRV_PCM_STARTAT_OP_STATUS, +}; + +enum { + SNDRV_PCM_STARTAT_CLOCK_TYPE_GETTIMEOFDAY = 0, + SNDRV_PCM_STARTAT_CLOCK_TYPE_MONOTONIC, + SNDRV_PCM_STARTAT_CLOCK_TYPE_LINK, + SNDRV_PCM_STARTAT_CLOCK_TYPE_LAST = SNDRV_PCM_STARTAT_CLOCK_TYPE_LINK, +}; + +struct snd_start_at { + int op; /* startat operation to be performed */ + union { /* fields for setting a startat timer */ + struct { + int clock_type; /* clock type e.g. SNDRV_PCM_STARTAT_CLOCK_TYPE_GETTIMEOFDAY */ + struct timespec start_time; /* start time */ + } set; + struct { + int clock_type; /* clock type e.g. SNDRV_PCM_STARTAT_CLOCK_TYPE_GETTIMEOFDAY */ + struct timespec current_time; + } status; + } args; +}; + /* channel positions */ enum { SNDRV_CHMAP_UNKNOWN = 0, @@ -550,6 +581,8 @@ enum { #define SNDRV_PCM_IOCTL_READN_FRAMES _IOR('A', 0x53, struct snd_xfern) #define SNDRV_PCM_IOCTL_LINK _IOW('A', 0x60, int) #define SNDRV_PCM_IOCTL_UNLINK _IO('A', 0x61) +#define SNDRV_PCM_IOCTL_START_AT _IOW('A', 0x62, struct snd_start_at) +
/***************************************************************************** * * diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c index c34b766..07c3a2e 100644 --- a/src/pcm/pcm_hw.c +++ b/src/pcm/pcm_hw.c @@ -620,6 +620,67 @@ static int snd_pcm_hw_start(snd_pcm_t *pcm) return 0; }
+static int snd_pcm_hw_start_at(snd_pcm_t *pcm, snd_pcm_startat_clock_type_t clock_type, const snd_htimestamp_t *start_time) +{ + snd_pcm_hw_t *hw = pcm->private_data; + int err; + + struct snd_start_at start_at = { + .op = SNDRV_PCM_STARTAT_OP_SET, + .args.set = { + .clock_type = clock_type, + .start_time = *start_time, + } + }; + + if (ioctl(hw->fd, SNDRV_PCM_IOCTL_START_AT, &start_at) < 0) { + err = -errno; + SYSMSG("SNDRV_PCM_IOCTL_START_AT failed (%i)", err); + return err; + } + return 0; +} + +static int snd_pcm_hw_start_at_abort(snd_pcm_t *pcm) +{ + snd_pcm_hw_t *hw = pcm->private_data; + int err; + + struct snd_start_at start_at = { + .op = SNDRV_PCM_STARTAT_OP_CANCEL, + }; + + if (ioctl(hw->fd, SNDRV_PCM_IOCTL_START_AT, &start_at) < 0) { + err = -errno; + SYSMSG("SNDRV_PCM_IOCTL_START_AT failed (%i)", err); + return err; + } + return 0; +} + +static int snd_pcm_hw_start_at_gettime(snd_pcm_t *pcm, snd_pcm_startat_clock_type_t clock_type, snd_htimestamp_t *current_time) +{ + snd_pcm_hw_t *hw = pcm->private_data; + int err; + + struct snd_start_at start_at = { + .op = SNDRV_PCM_STARTAT_OP_STATUS, + .args.status = { + .clock_type = clock_type, + } + }; + + if (ioctl(hw->fd, SNDRV_PCM_IOCTL_START_AT, &start_at) < 0) { + err = -errno; + SYSMSG("SNDRV_PCM_IOCTL_START_AT failed (%i)", err); + return err; + } + + *current_time = start_at.args.status.current_time; + + return 0; +} + static int snd_pcm_hw_drop(snd_pcm_t *pcm) { snd_pcm_hw_t *hw = pcm->private_data; @@ -1336,6 +1397,9 @@ static const snd_pcm_fast_ops_t snd_pcm_hw_fast_ops = { .prepare = snd_pcm_hw_prepare, .reset = snd_pcm_hw_reset, .start = snd_pcm_hw_start, + .start_at = snd_pcm_hw_start_at, + .start_at_abort = snd_pcm_hw_start_at_abort, + .start_at_gettime = snd_pcm_hw_start_at_gettime, .drop = snd_pcm_hw_drop, .drain = snd_pcm_hw_drain, .pause = snd_pcm_hw_pause, diff --git a/src/pcm/pcm_local.h b/src/pcm/pcm_local.h index 394505f..0ea6b61 100644 --- a/src/pcm/pcm_local.h +++ b/src/pcm/pcm_local.h @@ -154,6 +154,9 @@ typedef struct { int (*prepare)(snd_pcm_t *pcm); int (*reset)(snd_pcm_t *pcm); int (*start)(snd_pcm_t *pcm); + int (*start_at)(snd_pcm_t *pcm, snd_pcm_startat_clock_type_t clock_type, const snd_htimestamp_t *start_time); + int (*start_at_abort)(snd_pcm_t *pcm); + int (*start_at_gettime)(snd_pcm_t *pcm, snd_pcm_startat_clock_type_t clock_type, snd_htimestamp_t *current_time); int (*drop)(snd_pcm_t *pcm); int (*drain)(snd_pcm_t *pcm); int (*pause)(snd_pcm_t *pcm, int enable);